Hyperventilation: Difference between revisions

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{{Infobox_Disease |
__NOTOC__
  Name        = Hyperventilation |
{{Hyperventilation}}
  ICD10      = {{ICD10|R|06|4|r|00}} |
{{CMG}}; {{AE}} {{Vbe}}, {{IQ}}
  ICD9        = {{ICD9|786.01}} |_
 
}}
==Overview==
{{Infobox_Disease |
Hyperventilation is the state of rapid [[breath]]ing which results in the reduction in [[carbon dioxide]] levels (below normal) thereby leading to [[hypocapnia]].<ref name="02_calc">{{cite web | author=Kenneth Baillie and Alistair Simpson | title=Hyperventilation calculator | url=ttp://www.altitude.org/calculators/oxygencalculator/oxygencalculator.htm | publisher= Apex (Altitude Physiology EXpeditions) | accessdate=2006-08-10}} - Online interactive oxygen delivery calculator that mimicks hyperventilation</ref> During rapid breathing, the body loses more carbon dioxide (CO<sub>2</sub>) than it can produce resulting in net reduction of CO<sub>2</sub> levels. This state of rapid/faster breathing is most commonly seen in stress and anxiety and termed as [[hyperventilation syndrome]]. [[Kussmaul breathing]] is also a type of hyperventilation and done to reduce the [[acidity]] of body as seen in [[metabolic acidosis]]. Hyperventilation may also be voluntarily manifested following episodes of rapid deep breathing. The symptoms of hyperventilation are variable. Some patients are completely asymptomatic while others may present with minimal symptoms such as [[headache]] and [[numbness]] or [[tingling]] in the [[hands]], [[feet]], and [[lips]]. More severe symptoms include [[dizziness]], [[lightheadedness]], and [[fainting]]. Some patient also report having [[chest pain]] and [[slurred speech]] particularly when accompanied by the [[Valsalva maneuver]]. Voluntary deep breathing and induction of hyperventilation is a common practice among young individuals to attain focus and [[adrenaline]] rush. Other similar terms that are completely different from hyperventilation include [[Dyspnea|hyperpnea]] and [[Dyspnea|tachypnea]].
  Name        = Tachypnea |
 
  ICD10      = {{ICD10|R|06|0|r|00}} |
[[Dyspnea|Hyperpnea]] is commonly seen with exercise or any major physical activity as well as in response to hypoxic states. In these conditions the energy demand of the body either goes up or is not adequately met. To meet this energy deficit, the body increases the depth and rate of breathing which is known as [[hyperpnea]]. Other common examples of hyperpneic state include [[sepsis]], [[anemia]], and individuals living at high altitudes. [[Tachypnea]] is derived from a Greek word which means "rapid breathing". [[Tachypnea]] means rapid and shallow breathing and is also seen with exercise as a compensatory mechanism to increase the oxygen content of the body.
  ICD9        = {{ICD9|786.06}} |
 
}}
== Pathophysiology ==
{{SI}}
 
{{CMG}}
=== Physiology of breathing ===
The basic physiology of normal breathing is as follows:
* Under normal conditions, breathing is regulated by the [[central nervous system]] ([[CNS]]).


* The [[CNS]] regulates the depth and frequency of each breath to maintain normal levels of [[carbon dioxide]] (CO<sub>2</sub>) and [[oxygen]] (O<sub>2</sub>) in the [[blood]] and [[tissues]].
* The [[CNS]] measures the amount of CO<sub>2</sub> in the body to regulate the [[breathing]] process.
* As the CO<sub>2</sub> and O<sub>2</sub> gas exchange mechanism is simultaneous and continuous, any condition resulting in increased high [[carbon dioxide]] concentration primarily signals a low oxygen concentration.
* In addition, [[metabolism]] in the body uses O<sub>2</sub> and results in the production of CO<sub>2</sub> as a byproduct.


=== Hyperventilation ===
Under physiologic conditions, the volume of [[alveolar]] gas is in equilibrium with the [[arterial]] gas. <ref>{{cite book | last = Barrett | first = Kim | title = Ganong's review of medical physiology | publisher = McGraw-Hill Medical McGraw-Hill distributor |chapter = Chapter 34. Introduction to Pulmonary Structure and Mechanics | location = New York London | year = 2012 | isbn = 978-0071780032 }}</ref>
* With each breath approximately 10% of the [[alveolar]] gas is replaced with atmospheric air.
* The rate and depth of [[breathing]] determines the level of CO<sub>2</sub> in the body.
* A rapid and deep breath will lead to a better [[alveolar]] - atmospheric gas exchange leading to low CO<sub>2</sub> levels.
* It is to be noted that atmospheric air has 21% O2 content as compared to just 0.03% of CO<sub>2</sub> content.
* This results in low CO<sub>2</sub> content ([[hypocapnia]]) with each rapid and deep breath.


==Overview==
===Mechanism of Alkalosis===
In [[medicine]], '''hyperventilation''' (or '''overbreathing''') is the state of [[breath]]ing faster and/or deeper than necessary, thereby reducing the [[carbon dioxide]] concentration of the [[blood]] below normal.<ref name="02_calc">{{cite web | author=Kenneth Baillie and Alistair Simpson | title=Hyperventilation calculator | url=ttp://www.altitude.org/calculators/oxygencalculator/oxygencalculator.htm | publisher= Apex (Altitude Physiology EXpeditions) | accessdate=2006-08-10}} - Online interactive oxygen delivery calculator that mimicks hyperventilation</ref>
The mechanism of the development of [[alkalosis]] following hyperventilation is as follows:<ref name="Engelking2015">{{cite journal|last1=Engelking|first1=Larry R.|title=Respiratory Alkalosis|year=2015|pages=590–595|doi=10.1016/B978-0-12-391909-0.50091-8}}</ref>
*Majority of the CO<sub>2</sub> in human body is stored as [[carbonic acid]] and is a major factor in determining the pH of the body.
*Loss of CO<sub>2</sub> results in blood becoming more [[alkaline]] and increase in blood pH.
*In the normal individual, the resultant [[alkalosis]] would automatically be countered by reduced [[breathing]] except when the [[neural]] control is altered or disturbed.


This is in contrast to '''hyperpnea''', where the increased breathing is required to meet demand, as during and following exercise or when the body lacks [[oxygen]] ([[Hypoxia (medical)|hypoxia]]), for instance in high altitude or as a result of [[anaemia]]. Hyperpnea may also occur as a result of [[sepsis]], and is usually a sign of the beginning of refractory sepsis.
===Response of brain vasculature to hyperventilation and hypoventilation===
The response of [[vessels]] in the [[brain]] to hyperventilation and hypoventilation is as follows:<ref>{{cite journal |author=Stocchetti N, Maas AI, Chieregato A, van der Plas AA |title=Hyperventilation in head injury: a review |journal=Chest |volume=127 |issue=5 |pages=1812-27 |year=2005 |pmid=15888864 |doi=10.1378/chest.127.5.1812}}</ref><ref name="pmid15890697">{{cite journal| author=Ainslie PN, Ashmead JC, Ide K, Morgan BJ, Poulin MJ| title=Differential responses to CO2 and sympathetic stimulation in the cerebral and femoral circulations in humans. | journal=J Physiol | year= 2005 | volume= 566 | issue= Pt 2 | pages= 613-24 | pmid=15890697 | doi=10.1113/jphysiol.2005.087320 | pmc=1464750 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15890697  }} </ref><ref name="pmid21521758">{{cite journal| author=Battisti-Charbonney A, Fisher J, Duffin J| title=The cerebrovascular response to carbon dioxide in humans. | journal=J Physiol | year= 2011 | volume= 589 | issue= Pt 12 | pages= 3039-48 | pmid=21521758 | doi=10.1113/jphysiol.2011.206052 | pmc=3139085 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21521758  }} </ref>


Hyperventilation can, but does not necessarily cause symptoms such as [[numbness]] or [[tingling]] in the hands, feet and lips, [[lightheadedness]], [[dizziness]], [[headache]], [[chest pain]], slurred speech and sometimes [[fainting]], particularly when accompanied by the [[Valsalva maneuver]]. Sometimes hyperventilation is induced for these same effects. Hyperventilation can sometimes be self induced for moments of needed focus and [[adrenaline]].
*Conditions causing high CO<sub>2</sub> levels ([[hypercapnia]]) results in the body assuming that the O<sub>2</sub> levels are low.
*As a result, to increase the O<sub>2</sub> supply the [[blood vessels]] in the [[brain]] [[dilate]].


The related symptom '''tachypnea''' (or "tachypnoea") ([[Greek language|Greek]]: "rapid breathing") is characterized by rapid breathing and is not identical with hyperventilation - [[tachypnea]] may be necessary for a sufficient gas-exchange of the body, for example after exercise, in which case it is not hyperventilation.
*Alternatively, [[hypocapnia]] results in constriction of [[Brain|brain's]] [[blood vessels]] causing diminished blood flow leading to [[lightheadedness]].
*Thus, though it seems counterintuitive, breathing too much can result in a decrease in the oxygen supply to the [[brain]].
*Physicians often artificially induce hyperventilation after [[head injury]] to reduce the [[intracranial pressure]], although the treatment has potential risks.


==Causes==
==Causes==
Following are the various causes of hyperventilation.
===Life-Threatening Causes===
===Life-Threatening Causes===
*[[Diabetic ketoacidosis]]
*[[Diabetic ketoacidosis]]
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===Common Causes===
===Common Causes===
*[[Acute altitude sickness]]
*[[Acute altitude sickness]]
*[[Anxiety]]
*[[Ascites]]
*[[Ascites]]
*[[Asthma]]  
*[[Asthma]]  
*[[Chronic obstructive pulmonary disease]]  
*[[Chronic obstructive pulmonary disease]]  
*[[Congestive heart failure]]
*[[Congestive heart failure]]
*[[Drugs]]- [[Amphetamine]], [[Aspirin]]
*[[Drugs]] such as:
**[[Amphetamine]]
**[[Aspirin]]
*[[Encephalitis]]  
*[[Encephalitis]]  
*[[Exercise]]
*[[Exercise]]
*[[Fever]]
*[[Fever]]
*[[Graves' disease]] and
*[[Graves' disease]]  
*[[Head injury]]  
*[[Head injury]]  
*[[Hyperthyroidism]]
*[[Hyperthyroidism]]
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*[[Pulmonary embolus]]
*[[Pulmonary embolus]]
*[[Pulmonary fibrosis]]
*[[Pulmonary fibrosis]]
*[[stress (medicine)|Stress]]
*[[Stroke]]
*[[Stroke]]


===Causes by Organ System===
===Causes by Organ System===
{|style="width:80%; height:100px" border="1"
{| style="width:80%; height:100px" border="1"
|style="height:100px"; style="width:25%" border="1" bgcolor="LightSteelBlue" |'''Cardiovascular'''
| style="width:25%" bgcolor="LightSteelBlue" ; border="1" |'''Cardiovascular'''
|style="height:100px"; style="width:75%" border="1" bgcolor="Beige" |[[Cheyne-Stokes respiration|Cheyne-stokes respirations]], [[congestive cardiac failure]],[[pulmonary embolism]], [[stroke]]
| style="width:75%" bgcolor="Beige" ; border="1" |[[Cheyne-Stokes respiration|Cheyne-stokes respirations]], [[congestive cardiac failure]], [[pulmonary embolism]], [[stroke]]
|-
|-
|bgcolor="LightSteelBlue"| '''Chemical/Poisoning'''
| bgcolor="LightSteelBlue" | '''Chemical/Poisoning'''
|bgcolor="Beige"| [[Ammonium chloride ]],[[camphor ]],[[glycol ether ]],[[Chemical pneumonitis|inhalation of irritants]],[[methanol ]],[[Salicylate poisoning]],
| bgcolor="Beige" | [[Ammonium chloride]], [[camphor ]] , [[glycol ether ]] , [[Chemical pneumonitis|inhalation of irritants]], [[methanol]], [[salicylate poisoning]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Dental'''
| '''Dental'''
|bgcolor="Beige"| No underlying causes
| bgcolor="Beige" | No underlying causes
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Dermatologic'''
| '''Dermatologic'''
|bgcolor="Beige"| No underlying causes
| bgcolor="Beige" | No underlying causes
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Drug Side Effect'''
| '''Drug Side Effect'''
|bgcolor="Beige"| [[Aminophylline]], [[aspirin]], [[Coffee|coffee abuse]], [[pralidoxime]], [[tiagabine]]
| bgcolor="Beige" | [[Aminophylline]], [[aspirin]], [[Coffee|coffee abuse]], [[pralidoxime]], [[tiagabine]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Ear Nose Throat'''
| '''Ear Nose Throat'''
|bgcolor="Beige"| No underlying causes
| bgcolor="Beige" | No underlying causes
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Endocrine'''
| '''Endocrine'''
|bgcolor="Beige"|[[Diabetic ketoacidosis]], [[renal disease]]  
| bgcolor="Beige" |[[Diabetic ketoacidosis]], [[renal disease]]  
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Environmental'''
| '''Environmental'''
|bgcolor="Beige"|[[Acute stress disorder]]
| bgcolor="Beige" |[[Acute stress disorder]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Gastroenterologic'''
| '''Gastroenterologic'''
|bgcolor="Beige"|[[Abdominal surgery]], [[acute liver failure]], [[Porphyria|acute porphyria]], [[Hepatic failure|end stage liver failure ]], [[Cirrhosis|hepatic cirrhosis]], [[Anal fistula|intestinal fistula]], [[pyloric stenosis]]
| bgcolor="Beige" |[[Abdominal surgery]], [[acute liver failure]], [[Porphyria|acute porphyria]], [[Hepatic failure|end stage liver failure]], [[Cirrhosis|hepatic cirrhosis]], [[Anal fistula|intestinal fistula]], [[pyloric stenosis]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Genetic'''
| '''Genetic'''
|bgcolor="Beige"|[[Porphyria|Acute porphyria]], [[Argininosuccinic aciduria|arginosuccinic aciduria]], [[Carbamoyl phosphate synthetase I deficiency|carbamoylphosphate synthetase 1 deficiency disease]], [[Renal tubular acidosis|carbonic anhydrase va deficiency]], [[Fructose bisphosphatase deficiency|hereditary fructose-1,6-bisphosphatase deficiency]], Pitt-hopkins syndrome
| bgcolor="Beige" |[[Porphyria|Acute porphyria]], [[Argininosuccinic aciduria|arginosuccinic aciduria]], [[Carbamoyl phosphate synthetase I deficiency|carbamoylphosphate synthetase 1 deficiency disease]], [[Renal tubular acidosis|carbonic anhydrase va deficiency]], [[Fructose bisphosphatase deficiency|hereditary fructose-1,6-bisphosphatase deficiency]], Pitt-hopkins syndrome
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Hematologic'''
| '''Hematologic'''
|bgcolor="Beige"|[[Porphyria|Acute porphyria]]
| bgcolor="Beige" |[[Porphyria|Acute porphyria]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Iatrogenic'''
| '''Iatrogenic'''
|bgcolor="Beige"| No underlying causes
| bgcolor="Beige" | No underlying causes
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Infectious Disease'''
| '''Infectious Disease'''
|bgcolor="Beige"|[[CNS infection]], [[fever]]
| bgcolor="Beige" |[[CNS infection]], [[fever]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Musculoskeletal/Orthopedic'''
| '''Musculoskeletal/Orthopedic'''
|bgcolor="Beige"|Hip cancer
| bgcolor="Beige" |Hip cancer
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Neurologic'''
| '''Neurologic'''
|bgcolor="Beige"|[[Altitude sickness|Altitude sickness, acute]], [[brain trauma]], [[central neurogenic hyperventilation]], [[cerebrovascular accident]], [[CNS infection]], [[cree leukoencephalopathy ]], damaged respiratory pathways, [[epilepsy]], [[West syndrome|epileptic encephalopathy, early infantile, 2]], [[head injury]], [[intracranial space-occupying lesion]], [[meningoencephalitis]], [[pain]], Pitt-hopkins syndrome, [[raised intracranial pressure]], [[stroke]], [[Neurocardiogenic syncope|Vasovagal attacks]]
| bgcolor="Beige" |[[Altitude sickness|Altitude sickness, acute]] [[brain trauma]], [[central neurogenic hyperventilation]], [[cerebrovascular accident]], [[CNS infection]], [[Cree leukoencephalopathy]], damaged respiratory pathways, [[epilepsy]], [[West syndrome|epileptic encephalopathy, early infantile, 2]]; [[head injury]], [[intracranial space-occupying lesion]], [[meningoencephalitis]], [[pain]], Pitt-Hopkins syndrome, [[raised intracranial pressure]], [[stroke]], [[Vasovagal Syncope|vasovagal attacks]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Nutritional/Metabolic'''
| '''Nutritional/Metabolic'''
|bgcolor="Beige"| [[Diabetic ketoacidosis]], [[Fructose bisphosphatase deficiency|hereditary fructose-1,6-bisphosphatase deficiency]], [[heat stroke]], [[lactic acidosis]]
| bgcolor="Beige" | [[Diabetic ketoacidosis]], [[Fructose bisphosphatase deficiency|hereditary fructose-1,6-bisphosphatase deficiency]], [[heat stroke]], [[lactic acidosis]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Obstetric/Gynecologic'''
| '''Obstetric/Gynecologic'''
|bgcolor="Beige"| No underlying causes
| bgcolor="Beige" | No underlying causes
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Oncologic'''
| '''Oncologic'''
|bgcolor="Beige"|[[Lung cancer|Bronchial neoplasm]], rib tumor
| bgcolor="Beige" |[[Lung cancer|Bronchial neoplasm]], rib tumor
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Ophthalmologic'''
| '''Ophthalmologic'''
|bgcolor="Beige"| No underlying causes
| bgcolor="Beige" | No underlying causes
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Overdose/Toxicity'''
| '''Overdose/Toxicity'''
|bgcolor="Beige"|[[Metformin|Biguanide intolerance]]
| bgcolor="Beige" |[[Metformin|Biguanide intolerance]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Psychiatric'''
| '''Psychiatric'''
|bgcolor="Beige"|[[Acute stress disorder ]], [[Panic attack|Adult panic-anxiety syndrome]], [[agoraphobia]], [[anxiety ]], [[Briquet syndrome|Briquet's syndrome]], [[combat stress reaction ]], [[cree leukoencephalopathy ]], [[Stress (medicine)|Crying or severe distress]], [[Da Costa's syndrome|Da costa syndrome]], [[depression]], [[distress]], [[Excited state|excitement]], [[fear]], [[functional disorders]], [[grief]], [[hypochondriasis]], [[hysteria]], [[malingering]], [[pain]], [[panic attack ]], [[phobia]], [[Stereotypic movement disorder|primary habit disorder]], Rett's syndrome, [[schizophrenia]], [[stress]], [[Emotion|strong emotions]]
| bgcolor="Beige" |[[Acute stress disorder]], [[Panic attack|adult panic-anxiety syndrome]], [[agoraphobia]], [[anxiety]], [[Briquet syndrome|Briquet's syndrome]], [[combat stress reaction]], [[Cree leukoencephalopathy]],[[Stress (medicine)|crying or severe distress]], [[Da Costa's syndrome|Da Costa syndrome]], [[depression]], [[distress]], [[Excited state|excitement]], [[fear]], [[functional disorders]], [[grief]], [[hypochondriasis]], [[hysteria]], [[malingering]], [[pain]], [[panic attack]], [[phobia]], [[Stereotypic movement disorder|primary habit disorder]], [[Rett syndrome|Rett's syndrome]], [[schizophrenia]], [[stress]], [[Emotion|strong emotions]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Pulmonary'''
| '''Pulmonary'''
|bgcolor="Beige"|[[Acute altitude sickness]], [[apneustic respirations]], [[asthma]], [[ataxic respiration]], [[biot's respiration]], [[central neurogenic hyperventilation]], [[Cheyne-Stokes respiration|Cheyne-stokes respirations]], damaged respiratory pathways, [[Idiopathic pulmonary fibrosis|diffuse pulmonary fibrosis]], [[emphysema ]], [[hypocapnia]],[[hyperventilation syndrome]], [[Chemical pneumonitis|inhalation of irritants]], [[Acute lung injury|lung damage]], [[metabolic acidosis ]], [[High frequency ventilation|persistent hypoxemia]], [[pleural effusion]], [[pneumonia]], [[pneumothorax]], [[pulmonary embolism]], [[pulmonary oedema]]
| bgcolor="Beige" |[[Acute altitude sickness]], [[apneustic respirations]], [[asthma]], [[ataxic respiration]], [[biot's respiration]], [[central neurogenic hyperventilation]], [[Cheyne-Stokes respiration|Cheyne-stokes respirations]], damaged respiratory pathways, [[Idiopathic pulmonary fibrosis|diffuse pulmonary fibrosis]], [[emphysema ]] , [[hyperventilation syndrome]], [[Chemical pneumonitis|inhalation of irritants]], [[Acute lung injury|lung damage]], [[metabolic acidosis]], [[High frequency ventilation|persistent hypoxemia]], [[pleural effusion]], [[pneumonia]], [[pneumothorax]], [[pulmonary embolism]], [[pulmonary oedema]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Renal/Electrolyte'''
| '''Renal/Electrolyte'''
|bgcolor="Beige"|[[Acid-base imbalance ]], [[metabolic acidosis ]], [[phaeochromocytoma]], [[renal disease]]
| bgcolor="Beige" |[[Acid-base imbalance]], [[metabolic acidosis]], [[phaeochromocytoma]], [[renal disease]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Rheumatology/Immunology/Allergy'''
| '''Rheumatology/Immunology/Allergy'''
|bgcolor="Beige"| [[Asthma]], [[Anaphylactoid reaction|pseudoallergic reactions]]
| bgcolor="Beige" | [[Asthma]], [[Anaphylactoid reaction|pseudoallergic reactions]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Sexual'''
| '''Sexual'''
|bgcolor="Beige"| No underlying causes
| bgcolor="Beige" | No underlying causes
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Trauma'''
| '''Trauma'''
|bgcolor="Beige"|[[Brain trauma]], [[head injury]], [[Acute lung injury|lung damage]], [[raised intracranial pressure]], [[Pneumothorax|sponatneous pneumothorax]], [[stroke]], surgical relocation of ureters in ileum or colon
| bgcolor="Beige" |[[Brain trauma]], [[head injury]], [[Acute lung injury|lung damage]], [[raised intracranial pressure]], [[Pneumothorax|sponatneous pneumothorax]], [[stroke]], surgical relocation of ureters in ileum or colon
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Urologic'''
| '''Urologic'''
|bgcolor="Beige"| [[Ureterostomy|Surgical relocation of ureters in ileum or colon]]
| bgcolor="Beige" | [[Ureterostomy|Surgical relocation of ureters in ileum or colon]]
|-
|-
|-bgcolor="LightSteelBlue"
|- bgcolor="LightSteelBlue"
| '''Miscellaneous'''
| '''Miscellaneous'''
|bgcolor="Beige"|[[Abdominal surgery]], adulation, [[childbirth]], [[fever]]
| bgcolor="Beige" |[[Abdominal surgery]], adulation, [[childbirth]], [[fever]]
|}
|}


===Causes in Alphabetical Order===
===Causes in Alphabetical Order===
<code></code>{{columns-list|3|
{{columns-list|
*[[Abdominal surgery]]
*[[Abdominal surgery]]
*[[Acid-base imbalance]]
*[[Acid-base imbalance]]
Line 222: Line 248:
*[[Grief]]
*[[Grief]]
*[[Head injury]]
*[[Head injury]]
*[[Hypocapnia]]
*[[Hyperthermia|Heat stroke]]
*[[Hyperthermia|Heat stroke]]
*[[Cirrhosis|Hepatic cirrhosis]]
*[[Cirrhosis|Hepatic cirrhosis]]
Line 267: Line 292:
}}
}}


== Causes ==
== Differentiating Hyperventilation from other Diseases ==
[[stress (medicine)|Stress]] or [[anxiety]] commonly are causes of hyperventilation; this is known as [[hyperventilation syndrome]].
Various diseases that can cause hyperventilation may include diseases of [[Respiratory system|respiratory]], [[cardiovascular]], [[Endocrine system|endocrine]], [[central nervous system]], and [[Musculoskeletal system|musculoskeletal]] system. [[Pregnancy]], [[sepsis]], and [[hepatic failure]] are other conditions that may also result in hyperventilation. Given below is a differential diagnosis of diseases presenting with hyperventilation.


Hyperventilation can also be brought about voluntarily, by taking many deep breaths. Hyperventilation can also occur as a consequence of various [[lung]] diseases, head injury, coffee abuse<ref name="COAM">{{cite web | title = Caffeine overdose in an adolescent male | publisher = J Toxicol Clin Toxicol  | url = http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=3193494&query_hl=34&itool=pubmed_docsum|accessdate = 2006-08-14 }}</ref> or [[stroke]] ([[central neurogenic hyperventilation]], [[apneustic respirations]], [[ataxic respiration]], [[Cheyne-Stokes respirations]] or [[Biot's respiration]]).
<small>'''''Abbreviations:''''' '''ABG ('''[[arterial blood gas]]'''); ACE ('''[[Angiotensin-converting enzyme|angiotensin converting enzyme]]'''); βhCG ('''[[Human chorionic gonadotropin|beta human chorionic gonadotropin]]''');  BMP ('''[[basic metabolic panel]]'''); BNP ('''[[brain natriuretic peptide]]'''); CBC ('''[[Complete blood counts|complete blood count]]'''); COPD ('''[[Chronic obstructive pulmonary disease|chronic obstructive pulmonary disease''')''']]'''; CSF ('''[[cerebrospinal fluid]]'''); CXR ('''[[chest X-ray]]'''); CT ('''[[computed tomography]]'''); DLCO ('''[[DLCO|diffusing capacity of the lung for carbon monoxide]]'''); DOE ('''dyspnea on [[exercise]]'''); ECG ('''[[electrocardiogram]]'''); FEF ('''[[Spirometry|forced expiratory flow rate]]'''); FEV1 ('''[[forced expiratory volume]]'''); FT4 ('''[[free T4]]'''); FVC ('''[[forced vital capacity]]'''); HRCT ('''[[High Resolution CT|high resolution computed tomography]]'''); JVD ('''[[jugular vein distention]]''');''' '''LFTs ('''[[liver function tests]]'''); MCV ('''[[mean corpuscular volume]]''');  MEN ('''[[multiple endocrine neoplasia]]'''); MRI ('''[[magnetic resonance imaging]]'''); P2 ('''[[P2|pulmonic heart sound]]'''); Plt ('''[[platelet]]'''); PT ('''[[prothrombin time]]'''); RBC ('''[[red blood cell]]'''); RV ('''[[residual volume]]'''); SIADH ('''[[syndrome of inappropriate antidiuretic hormone]]'''); S3 (''' [[third heart sound]]'''); S4 ('''[[fourth heart sound]]'''); T3 ([[Triiodothyronine|(]]'''[[Triiodothyronine]]'''); TLC ('''[[total lung capacity]]'''); TSH ('''[[thyroid stimulating hormone]]'''); VC ('''[[vital capacity]]'''); VMA('''[[vanillylmandelic acid]])'''; Vt ('''[[tidal volume]]''');''' '''WBC ('''[[White blood cells|white blood cell]]''');'''</small>
{| class="wikitable" align="center" style="border: 0px; font-size: 90%; margin: 3px;"
! rowspan="3" style="background:#4479BA; color: #FFFFFF;" |Organ system
! rowspan="3" style="background:#4479BA; color: #FFFFFF;" |Diseases
! colspan="9" style="background:#4479BA; color: #FFFFFF;" |Clinical manifestations
! colspan="5" rowspan="2" style="background:#4479BA; color: #FFFFFF;" |Diagnosis
! rowspan="3" style="background:#4479BA; color: #FFFFFF;" |Other features
|-
! colspan="4" style="background:#4479BA; color: #FFFFFF;" |Symptoms
! colspan="5" style="background:#4479BA; color: #FFFFFF;" |Physical exam
|-
! style="background:#4479BA; color: #FFFFFF;" | Chest pain
! style="background:#4479BA; color: #FFFFFF;" | Dyspnea
! style="background:#4479BA; color: #FFFFFF;" | Fever
! style="background:#4479BA; color: #FFFFFF;" | Palpitations
! style="background:#4479BA; color: #FFFFFF;" | Cyanosis
! style="background:#4479BA; color: #FFFFFF;" | Tachypnea
! style="background:#4479BA; color: #FFFFFF;" | JVD
! style="background:#4479BA; color: #FFFFFF;" | Peripheral edema
! style="background:#4479BA; color: #FFFFFF;" | Auscultation
! style="background:#4479BA; color: #FFFFFF;" | ABGs
! style="background:#4479BA; color: #FFFFFF;" | Lab findings
! style="background:#4479BA; color: #FFFFFF;" | Imaging
! style="background:#4479BA; color: #FFFFFF;" | PFT
! style="background:#4479BA; color: #FFFFFF;" | Gold standard
|-
! rowspan="8" |[[Respiratory systems|Pulmonary system]]
![[Pneumothorax]]<ref name="pmid17621614">{{cite journal| author=Currie GP, Alluri R, Christie GL, Legge JS| title=Pneumothorax: an update. | journal=Postgrad Med J | year= 2007 | volume= 83 | issue= 981 | pages= 461-5 | pmid=17621614 | doi=10.1136/pgmj.2007.056978 | pmc=2600088 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17621614  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* [[Decreased breath sounds]]
| align="center" style="padding: 5px 5px; background: " | +/- [[Hypoxemia]]
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |[[X-ray|X- ray]] -
*[[Mediastinal|Mediastinal shift]]
*[[Deep sulcus sign]]
* [[Hydropneumothorax]]
[[CT-scans|CT-scan]] -
* bullae
| align="left" style="padding: 5px 5px; background: " |
* ↓[[Tidal volume|Vt]]
| align="left" style="padding: 5px 5px; background: " |
* [[CT-scans|CT-scan]]
| align="left" style="padding: 5px 5px; background: " |
*[[Hypoxia]]
*[[Hypercapnia]]
* Hyperresonance to [[percussion]]
* [[Vocal resonation|Vocal resonance]]
*[[Tactile fremitus]] decreased
|-
![[Pulmonary embolism]]<ref name="pmid23940438">{{cite journal| author=Bĕlohlávek J, Dytrych V, Linhart A| title=Pulmonary embolism, part I: Epidemiology, risk factors and risk stratification, pathophysiology, clinical presentation, diagnosis and nonthrombotic pulmonary embolism. | journal=Exp Clin Cardiol | year= 2013 | volume= 18 | issue= 2 | pages= 129-38 | pmid=23940438 | doi= | pmc=3718593 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23940438  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* [[S3]] or [[S4]] [[Gallop rhythm|gallop]]       
| align="center" style="padding: 5px 5px; background: " |[[Respiratory alkalosis]]
| align="left" style="padding: 5px 5px; background: " |
* ↑[[D-dimer]]                 
* ↑[[Troponin|Troponin levels]]
| align="left" style="padding: 5px 5px; background: " |
* [[Duplex Ultrasonography to Evaluate Asymptomatic Patients With Known or Suspected Carotid Stenosis|Duplex Ultrasonography]]
* [[Echocardiography]]
* [[Venography]]
* Ventilation-Perfusion Scanning
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* [[Pulmonary angiography|CT pulmonary angiography]]
| align="left" style="padding: 5px 5px; background: " |
* [[Hemoptysis]]
* History of [[venous thromboembolism]]<nowiki/>or [[coagulation]]<nowiki/>abnormalities
* History of Malignancy
|-
![[Pneumonia]]<ref name="pmid25165554">{{cite journal| author=Simonetti AF, Viasus D, Garcia-Vidal C, Carratalà J| title=Management of community-acquired pneumonia in older adults. | journal=Ther Adv Infect Dis | year= 2014 | volume= 2 | issue= 1 | pages= 3-16 | pmid=25165554 | doi=10.1177/2049936113518041 | pmc=4072047 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25165554  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
*[[Bronchial]] [[breath sounds]]
*[[Crepitations]]
*[[Bronchophony]]
*[[Egophony]]
*Whispering pectoriloquy
| align="center" style="padding: 5px 5px; background: " | +/- [[Hypoxemia]]
| align="left" style="padding: 5px 5px; background: " |
*↑[[WBC]]
*[[Serology]]([[Mycoplasma]], [[viruses]])
*[[Sputum]] [[Gram stain]] and [[Culture-bound syndrome|culture]]
*[[Blood culture]]
| align="left" style="padding: 5px 5px; background: " |
*[[Chest X-ray|CXR]]- [[Consolidation (medicine)|Lobar consolidation]], Air bronchogram;
*[[Atypical pneumonia]]: [[Interstitial lung disease|Diffuse interstitial infiltrates]]
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* Presence of [[lung]] infiltrates on [[Chest X-ray|CXR]]
* [[Blood culture|Blood cultures]]
| align="left" style="padding: 5px 5px; background: " |
* [[Altered mental status]]
* [[Tachycardia]]
* Rust-colored [[sputum]]
* Green [[sputum]]
* Red currant-jelly [[sputum]]
* [[Central cyanosis]]
|-
![[Chronic obstructive pulmonary disease|Exacerbation of asthma/COPD]]<ref name="pmid25177479">{{cite journal| author=Qureshi H, Sharafkhaneh A, Hanania NA| title=Chronic obstructive pulmonary disease exacerbations: latest evidence and clinical implications. | journal=Ther Adv Chronic Dis | year= 2014 | volume= 5 | issue= 5 | pages= 212-27 | pmid=25177479 | doi=10.1177/2040622314532862 | pmc=4131503 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25177479  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
*[[Decreased breath sounds]]
*[[Wheezing]]
*[[Crackles|Coarse crackles]]
| align="center" style="padding: 5px 5px; background: " | +/- [[Hypoxemia]]
| align="left" style="padding: 5px 5px; background: " |
*[[Complete blood count|CBC]] shows [[Hematocrit|↑hematocrit]]
*[[Sputum|Sputum evaluation]]
*[[Brain natriuretic peptide|BNP]]( to rule out [[heart failure]])
| align="left" style="padding: 5px 5px; background: " |
*[[Chest X-ray|CXR]] shows
*Hyperinflated lungs
*Flattening of the [[diaphragm]]
*Narrow heart shadow
*[[Cardiomegaly]]
| align="left" style="padding: 5px 5px; background: " |
*↑[[Total lung capacity|TLC]]
*↑[[Residual volume|RV]]
*↓[[Vital capacity]]
*↓[[DLCO|DLco]] ( [[Emphysema]])
*Normal [[DLCO|DLco]] ( [[Chronic bronchitis]])
| align="left" style="padding: 5px 5px; background: " |
*[[High Resolution CT|HRCT]] of the [[lung]]
| align="left" style="padding: 5px 5px; background: " |
*[[Productive cough]]
*[[Exercise intolerance]]
*[[Altered mental status]]
*Cor-pulmonale
*Hyperresonance on [[percussion]]
|-
![[Interstitial lung disease]]<ref name="pmid24552321">{{cite journal| author=Bohadana A, Izbicki G, Kraman SS| title=Fundamentals of lung auscultation. | journal=N Engl J Med | year= 2014 | volume= 370 | issue= 8 | pages= 744-51 | pmid=24552321 | doi=10.1056/NEJMra1302901 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24552321  }} </ref><ref name="pmid15928621">{{cite journal| author=Spicknall KE, Zirwas MJ, English JC| title=Clubbing: an update on diagnosis, differential diagnosis, pathophysiology, and clinical relevance. | journal=J Am Acad Dermatol | year= 2005 | volume= 52 | issue= 6 | pages= 1020-8 | pmid=15928621 | doi=10.1016/j.jaad.2005.01.006 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15928621  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* [[Crackles|Fine crackles]]
* Loud P2
| align="center" style="padding: 5px 5px; background: " | +/- [[Hypoxemia]]
| align="center" style="padding: 5px 5px; background: " |_
| align="left" style="padding: 5px 5px; background: " |
* [[Chest X-ray|CXR-]] Reticular infiltrates
* Honey combing
| align="left" style="padding: 5px 5px; background: " |
*↓[[FEV1]]
*↓[[FVC]]
*↓[[Total lung capacity|TLC]]
* ↓[[Residual volume|RV]]
*↓[[DLCO|DLco]]
*[[FEV1/FVC ratio|FEV1/FVC]] normal
| align="left" style="padding: 5px 5px; background: " |
* [[High Resolution CT|HRCT]] -more accurate than [[Chest X-ray|cxr]]
* Most accurate test is [[Skin biopsy|lung biopsy]]
| align="left" style="padding: 5px 5px; background: " |
*[[Physical examination]] shows [[clubbing]]
*[[Pulmonary compliance|Decreased pulmonary compliance]]
|-
![[Pulmonary shunt|Intrapulmonary shunt]]<ref name="pmid19335916">{{cite journal| author=Vodoz JF, Cottin V, Glérant JC, Derumeaux G, Khouatra C, Blanchet AS et al.| title=Right-to-left shunt with hypoxemia in pulmonary hypertension. | journal=BMC Cardiovasc Disord | year= 2009 | volume= 9 | issue=  | pages= 15 | pmid=19335916 | doi=10.1186/1471-2261-9-15 | pmc=2671488 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19335916  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* Diminished [[breath sounds]]
| align="center" style="padding: 5px 5px; background: " | +/- [[Hypoxemia]]
| align="left" style="padding: 5px 5px; background: " |
* [[Complete blood count|CBC]] shows [[anemia]] or [[polycythemia]]
| align="left" style="padding: 5px 5px; background: " |
* [[CXR]] and [[CT-scans|CT]] shows  a smooth [[nodule]] with a feeding [[artery]] and draining [[vein]]
| align="left" style="padding: 5px 5px; background: " |
* ↓[[Tidal volume|Vt]], ↑[[Residual volume|RV]] ([[physiological]])
| align="left" style="padding: 5px 5px; background: " |
*[[CT angiography|Pulmonary CT angiography]]
| align="left" style="padding: 5px 5px; background: " |
* [[Clubbing]]
* [[Chronic]] [[hypoxemia]]
|-
![[Upper airway obstruction]]<ref name="pmid26495798">{{cite journal| author=Darras KE, Roston AT, Yewchuk LK| title=Imaging Acute Airway Obstruction in Infants and Children. | journal=Radiographics | year= 2015 | volume= 35 | issue= 7 | pages= 2064-79 | pmid=26495798 | doi=10.1148/rg.2015150096 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26495798  }} </ref>
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -/+
| align="center" style="padding: 5px 5px; background: " | -/+
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -/+
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* [[Stridor|Inspiratory stridor]]
| align="center" style="padding: 5px 5px; background: " | +/- [[Hypoxemia]]
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
*Plain [[Radiography|radiograph]] of the [[neck]]
*[[Steeple sign|Steeple sign (Croup in pediatric population)]]
* Thumb sign ([[Epiglottitis]])
*[[CT]]
*[[MRI]]
| align="left" style="padding: 5px 5px; background: " |
* ↓[[Vital capacity|VC]]
| align="left" style="padding: 5px 5px; background: " |
* [[High Resolution CT|HRCT]]
* [[Bronchoscopy]]
| align="left" style="padding: 5px 5px; background: " |
* [[Hoarseness]]
* [[Accessory muscles of respiration|Accessory muscle use during respiration]]
* [[Retraction (kinesiology)|Chest retractions]]
|-
![[High altitude sickness]]<ref name="pmid12801752">{{cite journal| author=Basnyat B, Murdoch DR| title=High-altitude illness. | journal=Lancet | year= 2003 | volume= 361 | issue= 9373 | pages= 1967-74 | pmid=12801752 | doi=10.1016/S0140-6736(03)13591-X | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12801752  }} </ref><ref name="pmid18682459">{{cite journal| author=Schoene RB| title=Illnesses at high altitude. | journal=Chest | year= 2008 | volume= 134 | issue= 2 | pages= 402-416 | pmid=18682459 | doi=10.1378/chest.07-0561 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18682459  }} </ref><ref name="pmid19099331">{{cite journal| author=Stream JO, Grissom CK| title=Update on high-altitude pulmonary edema: pathogenesis, prevention, and treatment. | journal=Wilderness Environ Med | year= 2008 | volume= 19 | issue= 4 | pages= 293-303 | pmid=19099331 | doi=10.1580/07-WEME-REV-173.1 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19099331  }} </ref>
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +
| align="left" style="padding: 5px 5px; background: " |
* [[Crackles]]
| align="center" style="padding: 5px 5px; background: " |[[Respiratory alkalosis]]
| align="left" style="padding: 5px 5px; background: " |
*[[The electrocardiogram|EKG]]- Right sided heart strain
| align="left" style="padding: 5px 5px; background: " |
*[[Chest X-ray|CXR]]- Bilateral patchy infiltrates
*[[CT Scan|Brain Ct scan]]
| align="left" style="padding: 5px 5px; background: " |
* ↓[[FVC]]
| align="left" style="padding: 5px 5px; background: " |
* Test in a hypobaric chamber with and without supplemental O2-breathing
| align="left" style="padding: 5px 5px; background: " |
* [[Altered mental status]]
* [[Urinary bladder]] distention
*[[Pulmonary edema]]
*[[Epistaxis]]
*[[Headache]]
*[[Rapid pulse]]
|-
! rowspan="4" |[[Cardiovascular system]]
![[Acute coronary syndromes|Acute coronary syndrome]]<ref name="pmid18307844">{{cite journal| author=Bruyninckx R, Aertgeerts B, Bruyninckx P, Buntinx F| title=Signs and symptoms in diagnosing acute myocardial infarction and acute coronary syndrome: a diagnostic meta-analysis. | journal=Br J Gen Pract | year= 2008 | volume= 58 | issue= 547 | pages= 105-11 | pmid=18307844 | doi=10.3399/bjgp08X277014 | pmc=2233977 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18307844  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="left" style="padding: 5px 5px; background: " |
* [[S3]]
*[[Systolic murmurs|Systolic murmur]]
*[[Rales]]
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
*Elevated [[cardiac enzymes]]
* ↑[[Brain natriuretic peptide|BNP]]
* [[EKG]]
| align="left" style="padding: 5px 5px; background: " |
*[[Chest X-ray|CXR]] shows [[Cardiomegaly|(Cardiomegaly]], [[Pulmonary edema]])
*[[Echocardiography]]
*[[Myocardial perfusion scan|Myocardial perfusion imaging]]
*[[Coronary angiography|Cardiac angiography]]
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* Elevated [[Cardiac enzymes|<nowiki>[[Cardiac enzymes|cardiac biomarkers [Cardiac troponin I, cardiac troponin]]</nowiki>]]
** [[Coronary angiography]]
| align="left" style="padding: 5px 5px; background: " |
* [[Nausea and vomiting]
* [[Diaphoresis]]
* [[Presyncope]]
* [[Palpitation|Palpitations]]
* Lateral displacement of the [[apical impulse]]
|-
![[Heart failure]]<ref name="GagginJanuzzi2013">{{cite journal|last1=Gaggin|first1=Hanna K.|last2=Januzzi|first2=James L.|title=Biomarkers and diagnostics in heart failure|journal=Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease|volume=1832|issue=12|year=2013|pages=2442–2450|issn=09254439|doi=10.1016/j.bbadis.2012.12.014}}</ref>


Lastly, in the case of metabolic [[acidosis]], the body uses hyperventilation to counter the increased acidity of the blood; this is known as [[Kussmaul breathing]].
| align="center" style="padding: 5px 5px; background: " | +/-
 
| align="center" style="padding: 5px 5px; background: " | +
== Mechanism ==
| align="center" style="padding: 5px 5px; background: " | -
In normal breathing, both the depth and frequency of breaths is varied by the neural system primarily in order to maintain normal amounts of [[carbon dioxide]] but also to supply appropriate levels of [[oxygen]] to the body's tissues. This is mainly done by measuring the [[carbon dioxide]] content of the blood; normally, a high [[carbon dioxide]] concentration signals a low oxygen concentration, as we breathe in oxygen and breathe out carbon dioxide at the same time, and the body's cells use oxygen to burn fuel molecules to carbon dioxide.
| align="center" style="padding: 5px 5px; background: " | +/-
 
| align="center" style="padding: 5px 5px; background: " | +
The gases in the [[alveoli]] of the lungs are nearly in equilibrium with the gases in the [[blood]]. Normally, less than 10% of the gas in the alveoli is replaced each breath. Deeper or quicker breaths exchange more of the alveolar gas with air and have the net effect of drawing more [[carbon dioxide]] out of the body, since the carbon dioxide concentration in normal air is very low.
| align="center" style="padding: 5px 5px; background: " | +/-
 
| align="center" style="padding: 5px 5px; background: " | +
The resulting low concentration of [[carbon dioxide]] in the blood is known as [[hypocapnia]]. Since [[carbon dioxide]] is held in the blood mostly in the form of [[carbonic acid]], [[hypocapnia]] results in the blood becoming [[alkaline]], i.e. the blood [[pH value]] rises. (In the normal person, this [[alkalosis]] would automatically be countered by reduced breathing, but for various reasons this doesn't happen when the neural control is not present.)
| align="center" style="padding: 5px 5px; background: " | +
 
| align="left" style="padding: 5px 5px; background: " |
If carbon dioxide levels are high, the body assumes that oxygen levels are low, and accordingly the brain's blood vessels dilate, to assure sufficient blood flow and supply of oxygen. Conversely, low carbon dioxide levels (e.g. from hyperventilation) cause the brain's blood vessels to constrict, resulting in reduced blood flow to the brain and lightheadednessThus, though it seems counterintuitive, breathing too much can result in a decrease in the oxygen supply to the brain.  Doctors sometimes artificially induce hyperventilation after head injury to reduce the pressure in the skull, though the treatment has potential risks.<ref>{{cite journal |author=Stocchetti N, Maas AI, Chieregato A, van der Plas AA |title=Hyperventilation in head injury: a review |journal=Chest |volume=127 |issue=5 |pages=1812-27 |year=2005 |pmid=15888864 |doi=10.1378/chest.127.5.1812}}</ref>
* [[S4|S]]3
 
| align="center" style="padding: 5px 5px; background: " |[[Respiratory alkalosis]]
The high pH value resulting from hyperventilation also reduces the level of available [[calcium]] ([[hypocalcemia]]), which affects the nerves and causes the numbness or tingling of the hands.
| align="left" style="padding: 5px 5px; background: " |
This occurs because alkalinisation of the plasma proteins (mainly albumin) increases their calcium affinity.
* [[Hyponatremia]]
* [[Hypoalbuminemia]]
* ↑ [[Brain natriuretic peptide|(BNP)]]
* [[EKG]] ( to know underlying cause)
| align="left" style="padding: 5px 5px; background: " |[[CXR]] shows
*↑[[Cardiothoracic ratio]]
*[[Pulmonary edema]]
*[[Cardiomegaly]]
*[[Pleural effusion]]
| align="left" style="padding: 5px 5px; background: " |
* ↓[[Tidal volume|Vt]]
| align="left" style="padding: 5px 5px; background: " |
*[[B-type natriuretic peptide|B-type natriuretic peptide (BNP)]] and [[N-terminal pro b-type natriuretic peptide|N-terminal proBNP (NT-proBNP)]]
| align="left" style="padding: 5px 5px; background: " |
*[[Dyspnea]]
*[[Orthopnea]]
*[[Paroxysmal nocturnal dyspnea]]
* [[Excessive sweating]]
* [[High blood pressure]]
*[[Hepatojugular reflux]]
|-
![[Dysrhythmias]]<ref name="pmid18307844">{{cite journal| author=Bruyninckx R, Aertgeerts B, Bruyninckx P, Buntinx F| title=Signs and symptoms in diagnosing acute myocardial infarction and acute coronary syndrome: a diagnostic meta-analysis. | journal=Br J Gen Pract | year= 2008 | volume= 58 | issue= 547 | pages= 105-11 | pmid=18307844 | doi=10.3399/bjgp08X277014 | pmc=2233977 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18307844  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* High [[pulse rate]]
| align="center" style="padding: 5px 5px; background: " |Normal
| align="left" style="padding: 5px 5px; background: " |
* Abnormal [[Basic metabolic panel|BMP]]
* [[Electrolyte disturbance|Electrolytes disturbances]]
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* [[ECG]]
| align="left" style="padding: 5px 5px; background: " |
* Caused by [[Cardiac|cardiac,]] [[psychiatric]], [[medications]], [[thyrotoxicosis]] and [[caffeine]] etc
|-
![[Shock]]<ref name="pmid26158402">{{cite journal| author=Churpek MM, Zadravecz FJ, Winslow C, Howell MD, Edelson DP| title=Incidence and Prognostic Value of the Systemic Inflammatory Response Syndrome and Organ Dysfunctions in Ward Patients. | journal=Am J Respir Crit Care Med | year= 2015 | volume= 192 | issue= 8 | pages= 958-64 | pmid=26158402 | doi=10.1164/rccm.201502-0275OC | pmc=4642209 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26158402  }} </ref><ref name="pmid11809551">{{cite journal| author=Kelly AM, Kyle E, McAlpine R| title=Venous pCO(2) and pH can be used to screen for significant hypercarbia in emergency patients with acute respiratory disease. | journal=J Emerg Med | year= 2002 | volume= 22 | issue= 1 | pages= 15-9 | pmid=11809551 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11809551  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="left" style="padding: 5px 5px; background: " |
* [[Stridor]]
* [[Wheezing]]
| align="center" style="padding: 5px 5px; background: " |Combined [[acid-base disorders]] are frequently encountered in different stages
| align="left" style="padding: 5px 5px; background: " |
* ↑[[WBC]]
| align="left" style="padding: 5px 5px; background: " |
* [[Chest X-ray|CXR]] (for finding the [[Cardiac|cardiac causes]])
| align="left" style="padding: 5px 5px; background: " |
* ↓[[Tidal volume|Vt]]
| align="left" style="padding: 5px 5px; background: " |
* Depends on the [[Causes|cause]] of [[shock]]
| align="left" style="padding: 5px 5px; background: " |
* [[Pulsus paradoxus]]
* [[Pulsus alternans]]
* [[Altered mental status]]
* [[Volume status#Volume depletion|Decreased skin turgor]]
|-
! rowspan="3" |[[Metabolic disorders|Metabolic/Systemic disorders]]
![[Diabetic ketoacidosis]]<ref name="pmid23547550">{{cite journal| author=Westerberg DP| title=Diabetic ketoacidosis: evaluation and treatment. | journal=Am Fam Physician | year= 2013 | volume= 87 | issue= 5 | pages= 337-46 | pmid=23547550 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23547550  }} </ref>
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* Scattered [[wheeze]]
* [[Kussmaul breathing|Kussmaul's respiration]]                 
| align="center" style="padding: 5px 5px; background: " |[[Metabolic acidosis]]
| align="left" style="padding: 5px 5px; background: " |
*↑[[WBC]] in [[septic shock]]
*[[Anion gap]] [[metabolic acidosis]]
*[[Serum]] [[ketones]]
*[[Urinary System|Urinary]] [[ketones]]
*[[Hyponatremia]]
*[[Hyperkalemia]]
*[[Hyperosmolality]]
* [[Increased bowel sounds|Increased]] [[blood]] [[glucose]]
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* [[Blood test]] ([[acidosis]], [[hyperglycemia]], [[ketonemia]])
| align="left" style="padding: 5px 5px; background: " |
*[[Vomiting]]
*[[Abdominal pain]]
*[[Weakness]]
*[[Confusion]]
*[[Kussumal's breathing]]
*[[Polydipsia]]
*[[Polyuria]]
|-
![[Hypocalcemia]]<ref name="pmid8325292">{{cite journal| author=Tohme JF, Bilezikian JP| title=Hypocalcemic emergencies. | journal=Endocrinol Metab Clin North Am | year= 1993 | volume= 22 | issue= 2 | pages= 363-75 | pmid=8325292 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8325292  }} </ref><ref name="pmid18535072">{{cite journal| author=Cooper MS, Gittoes NJ| title=Diagnosis and management of hypocalcaemia. | journal=BMJ | year= 2008 | volume= 336 | issue= 7656 | pages= 1298-302 | pmid=18535072 | doi=10.1136/bmj.39582.589433.BE | pmc=2413335 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18535072  }} </ref>
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* [[Wheezing]]
| align="center" style="padding: 5px 5px; background: " |[[Respiratory alkalosis]]
| align="left" style="padding: 5px 5px; background: " |
* ↓Serum ionized [[calcium]]
* [[Serum albumin|Abnormal serum Albumin level]]
* [[Electrolyte disturbance|Electrolytes disturbances]]
*Serum 25 -hydroxy Vitamin D
*Serum PTH ( Parathyroid hormone)
| align="left" style="padding: 5px 5px; background: " |
* [[ECG]] shows [[prolongation of the QT interval]]
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* Serum Ionized calcium
| align="left" style="padding: 5px 5px; background: " |
*  [[Tetany]]
* [[Trousseau's sign]]
* [[Chvostek's sign]]
* [[Seizures]]
|-
![[Hypoglycemia]]<ref name="pmid1797507">{{cite journal| author=Hepburn DA, Deary IJ, Frier BM, Patrick AW, Quinn JD, Fisher BM| title=Symptoms of acute insulin-induced hypoglycemia in humans with and without IDDM. Factor-analysis approach. | journal=Diabetes Care | year= 1991 | volume= 14 | issue= 11 | pages= 949-57 | pmid=1797507 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1797507  }} </ref><ref name="pmid8243825">{{cite journal| author=Towler DA, Havlin CE, Craft S, Cryer P| title=Mechanism of awareness of hypoglycemia. Perception of neurogenic (predominantly cholinergic) rather than neuroglycopenic symptoms. | journal=Diabetes | year= 1993 | volume= 42 | issue= 12 | pages= 1791-8 | pmid=8243825 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8243825  }} </ref>
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* [[Rales]], [[rhonchi]] or [[crackles]]
| align="center" style="padding: 5px 5px; background: " |Normal
| align="left" style="padding: 5px 5px; background: " |
* [[Insulin|Serum insulin levels]]
* ↓Serum glucose levels
* [[Oral glucose tolerance test]]
| align="left" style="padding: 5px 5px; background: " |
* [[Octreotide|Octreotide scanning]] localizes [[Insulinoma|insulinomas]]
* [[Computed tomography|CT scan]]
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* 72-hour supervised fasting test
| align="left" style="padding: 5px 5px; background: " |
* [[Autonomic nervous system|Neurogenic (autonomic) symptoms]]
* Neuroglycopenic [[symptoms]]
|-
! rowspan="2" |[[Endocrine system]]
![[Hyperthyroidism]]<ref name="pmid15963064">{{cite journal| author=Iglesias P, Acosta M, Sánchez R, Fernández-Reyes MJ, Mon C, Díez JJ| title=Ambulatory blood pressure monitoring in patients with hyperthyroidism before and after control of thyroid function. | journal=Clin Endocrinol (Oxf) | year= 2005 | volume= 63 | issue= 1 | pages= 66-72 | pmid=15963064 | doi=10.1111/j.1365-2265.2005.02301.x | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15963064 }} </ref><ref name="pmid7121544">{{cite journal| author=Forfar JC, Muir AL, Sawers SA, Toft AD| title=Abnormal left ventricular function in hyperthyroidism: evidence for a possible reversible cardiomyopathy. | journal=N Engl J Med | year= 1982 | volume= 307 | issue= 19 | pages= 1165-70 | pmid=7121544 | doi=10.1056/NEJM198211043071901 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=7121544  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* [[Systolic hypertension]] with [[wide pulse pressure]]
| align="center" style="padding: 5px 5px; background: " |Variable
| align="left" style="padding: 5px 5px; background: " |
* ↓[[TSH]]
* ↑[[Free T4|FT<sub>4</sub>]] and ↑[[Total T3|total T<sub>3</sub>]]
* [[Autoantibody|Autoantibody studies]]
| align="left" style="padding: 5px 5px; background: " |
*  Diffuse or nodular pattern of uptake on [[Radioactive iodine uptake|thyroid scanning]]
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* [[TSH|Serum TSH level]]
| align="left" style="padding: 5px 5px; background: " |
* [[Nervousness]]
* [[Anxiety]]
* [[Perspiration|Increased perspiration]]
* Heat intolerance
|-
![[Pheochromocytoma]]<ref name="pmid15328326">{{cite journal| author=Neumann HP, Pawlu C, Peczkowska M, Bausch B, McWhinney SR, Muresan M et al.| title=Distinct clinical features of paraganglioma syndromes associated with SDHB and SDHD gene mutations. | journal=JAMA | year= 2004 | volume= 292 | issue= 8 | pages= 943-51 | pmid=15328326 | doi=10.1001/jama.292.8.943 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15328326  }} </ref><ref name="pmid1787652">{{cite journal| author=Bravo EL| title=Pheochromocytoma: new concepts and future trends. | journal=Kidney Int | year= 1991 | volume= 40 | issue= 3 | pages= 544-56 | pmid=1787652 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1787652  }} </ref>
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* Asymmetric [[chest]] expansion
| align="center" style="padding: 5px 5px; background: " |Normal
| align="left" style="padding: 5px 5px; background: " |
* Elevated [[plasma]] and [[urinary]] [[Catecholamine|catecholamines]] and [[Metanephrine|metanephrines]]
* Elevated urinary [[vanillyl mandelic acid]]
| align="left" style="padding: 5px 5px; background: " |
* [[Radiological]] evaluation is done to locate site of the [[tumor]]
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* [[Urine catecholamines|24-hour urine test for metanephrines, catecholamines and VMA]]
| align="left" style="padding: 5px 5px; background: " |
* [[Multiple endocrine neoplasia type 1|MEN 1]] and [[Multiple endocrine neoplasia type 2|MEN 2 syndrome]]
|-
! rowspan="2" |[[CNS]]
![[Central nervous system tumors|Central nervous system tumor]]<ref name="pmid8414011">{{cite journal| author=Forsyth PA, Posner JB| title=Headaches in patients with brain tumors: a study of 111 patients. | journal=Neurology | year= 1993 | volume= 43 | issue= 9 | pages= 1678-83 | pmid=8414011 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8414011 }} </ref><ref name="pmid19673912">{{cite journal| author=Valentinis L, Tuniz F, Valent F, Mucchiut M, Little D, Skrap M et al.| title=Headache attributed to intracranial tumours: a prospective cohort study. | journal=Cephalalgia | year= 2010 | volume= 30 | issue= 4 | pages= 389-98 | pmid=19673912 | doi=10.1111/j.1468-2982.2009.01970.x | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19673912  }} </ref>
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="center" style="padding: 5px 5px; background: " |Variable based on tumor location
| align="left" style="padding: 5px 5px; background: " |
* [[CSF analysis]] can show cancerous cell
| align="left" style="padding: 5px 5px; background: " |
* [[Magnetic resonance imaging|Magnetic resonance imaging (MRI) with contrast]]
* [[CT scan]] is done in [[Emergency|emergencies]]
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* [[Magnetic resonance imaging|Contrast-enhanced magnetic resonance imaging (MRI)]]
| align="left" style="padding: 5px 5px; background: " |
* [[Headache]]
* [[Seizure|Seizures]]
* Focal deficits
|-
![[Anxiety|Anxiety/panic attacks]]<ref name="pmid16627512">{{cite journal| author=Taylor CB| title=Panic disorder. | journal=BMJ | year= 2006 | volume= 332 | issue= 7547 | pages= 951-5 | pmid=16627512 | doi=10.1136/bmj.332.7547.951 | pmc=1444835 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16627512  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="center" style="padding: 5px 5px; background: " |Normal
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* [[Clinical]] assessment
* [[Psychological|Psychological              interview]]
| align="left" style="padding: 5px 5px; background: " |
* [[Sweating]] [[Palpitation]]
* [[Anxiety|Severe anxiety]]
|-
! rowspan="3" |Others
![[Pregnancy]]<ref name="pmid28805596">{{cite journal| author=Lee SY, Chien DK, Huang CH, Shih SC, Lee WC, Chang WH| title=Dyspnea in pregnancy. | journal=Taiwan J Obstet Gynecol | year= 2017 | volume= 56 | issue= 4 | pages= 432-436 | pmid=28805596 | doi=10.1016/j.tjog.2017.04.035 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=28805596  }} </ref>
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="center" style="padding: 5px 5px; background: " |[[Respiratory alkalosis]]
| align="left" style="padding: 5px 5px; background: " |
* ↑[[WBC]]
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* ↓[[Tidal volume|Vt]], ↑[[Residual volume|RV]]
| align="left" style="padding: 5px 5px; background: " |
* [[Human chorionic gonadotropin|βhCG]]
| align="left" style="padding: 5px 5px; background: " |
* [[Periods|Missed period]]
* [[Hyperemesis gravidarum|Hyperemesis]]
|-
![[Hepatic failure]]<ref name="pmid8305063">{{cite journal| author=Lee WM| title=Acute liver failure. | journal=N Engl J Med | year= 1993 | volume= 329 | issue= 25 | pages= 1862-72 | pmid=8305063 | doi=10.1056/NEJM199312163292508 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8305063  }} </ref><ref name="pmid11500606">{{cite journal| author=Gill RQ, Sterling RK| title=Acute liver failure. | journal=J Clin Gastroenterol | year= 2001 | volume= 33 | issue= 3 | pages= 191-8 | pmid=11500606 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11500606  }} </ref>
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +
| align="left" style="padding: 5px 5px; background: " |
* [[Right ventricular]] [[Gallop rhythm|gallop]]
| align="center" style="padding: 5px 5px; background: " | +/- [[Respiratory alkalosis]]
| align="left" style="padding: 5px 5px; background: " |
* [[Liver function tests|Abnormal LFTs]]
* [[Prothrombin time|Abnormal PT time]]
* Abnormal serum [[ammonia]]
| align="left" style="padding: 5px 5px; background: " |
* [[Doppler ultrasonography]] can show [[ascites]], patency of [[hepatic artery]], [[hepatic vein]] and [[portal vein]]
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* [[Liver biopsy]]
| align="left" style="padding: 5px 5px; background: " |
* [[Jaundice]]
* [[Encephalopathy]]
|-
![[Sepsis]]<ref name="pmid27216810">{{cite journal| author=Askim Å, Mehl A, Paulsen J, DeWan AT, Vestrheim DF, Åsvold BO et al.| title=Epidemiology and outcome of sepsis in adult patients with Streptococcus pneumoniae infection in a Norwegian county 1993-2011: an observational study. | journal=BMC Infect Dis | year= 2016 | volume= 16 | issue=  | pages= 223 | pmid=27216810 | doi=10.1186/s12879-016-1553-8 | pmc=4877975 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=27216810  }} </ref>
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | +
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | +/-
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="center" style="padding: 5px 5px; background: " | -
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="center" style="padding: 5px 5px; background: " |Variable based on the sepsis phase
| align="left" style="padding: 5px 5px; background: " |
* [[WBC|↑WBC]], [[neutrophilia]]
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* Normal
| align="left" style="padding: 5px 5px; background: " |
* [[SIRS|SIRS criteria]]
| align="left" style="padding: 5px 5px; background: " |
* [[Chills]]
* [[Confusion]]
|}


==References==
==References==
<references/>
<references />


== See also ==
== See also ==
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[[pt:Hiperventilação]]
[[pt:Hiperventilação]]
[[pl:Tachypnoe]]
[[pl:Tachypnoe]]


[[Category:Abnormal respiration]]
[[Category:Abnormal respiration]]

Latest revision as of 21:19, 10 January 2020

Dyspnea Microchapters

Overview

Pathophysiology

Causes

Differentiating Hyperventilation from other Diseases

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2], Iqra Qamar M.D.[3]

Overview

Hyperventilation is the state of rapid breathing which results in the reduction in carbon dioxide levels (below normal) thereby leading to hypocapnia.[1] During rapid breathing, the body loses more carbon dioxide (CO2) than it can produce resulting in net reduction of CO2 levels. This state of rapid/faster breathing is most commonly seen in stress and anxiety and termed as hyperventilation syndrome. Kussmaul breathing is also a type of hyperventilation and done to reduce the acidity of body as seen in metabolic acidosis. Hyperventilation may also be voluntarily manifested following episodes of rapid deep breathing. The symptoms of hyperventilation are variable. Some patients are completely asymptomatic while others may present with minimal symptoms such as headache and numbness or tingling in the hands, feet, and lips. More severe symptoms include dizziness, lightheadedness, and fainting. Some patient also report having chest pain and slurred speech particularly when accompanied by the Valsalva maneuver. Voluntary deep breathing and induction of hyperventilation is a common practice among young individuals to attain focus and adrenaline rush. Other similar terms that are completely different from hyperventilation include hyperpnea and tachypnea.

Hyperpnea is commonly seen with exercise or any major physical activity as well as in response to hypoxic states. In these conditions the energy demand of the body either goes up or is not adequately met. To meet this energy deficit, the body increases the depth and rate of breathing which is known as hyperpnea. Other common examples of hyperpneic state include sepsis, anemia, and individuals living at high altitudes. Tachypnea is derived from a Greek word which means "rapid breathing". Tachypnea means rapid and shallow breathing and is also seen with exercise as a compensatory mechanism to increase the oxygen content of the body.

Pathophysiology

Physiology of breathing

The basic physiology of normal breathing is as follows:

  • The CNS regulates the depth and frequency of each breath to maintain normal levels of carbon dioxide (CO2) and oxygen (O2) in the blood and tissues.
  • The CNS measures the amount of CO2 in the body to regulate the breathing process.
  • As the CO2 and O2 gas exchange mechanism is simultaneous and continuous, any condition resulting in increased high carbon dioxide concentration primarily signals a low oxygen concentration.
  • In addition, metabolism in the body uses O2 and results in the production of CO2 as a byproduct.

Hyperventilation

Under physiologic conditions, the volume of alveolar gas is in equilibrium with the arterial gas. [2]

  • With each breath approximately 10% of the alveolar gas is replaced with atmospheric air.
  • The rate and depth of breathing determines the level of CO2 in the body.
  • A rapid and deep breath will lead to a better alveolar - atmospheric gas exchange leading to low CO2 levels.
  • It is to be noted that atmospheric air has 21% O2 content as compared to just 0.03% of CO2 content.
  • This results in low CO2 content (hypocapnia) with each rapid and deep breath.

Mechanism of Alkalosis

The mechanism of the development of alkalosis following hyperventilation is as follows:[3]

  • Majority of the CO2 in human body is stored as carbonic acid and is a major factor in determining the pH of the body.
  • Loss of CO2 results in blood becoming more alkaline and increase in blood pH.
  • In the normal individual, the resultant alkalosis would automatically be countered by reduced breathing except when the neural control is altered or disturbed.

Response of brain vasculature to hyperventilation and hypoventilation

The response of vessels in the brain to hyperventilation and hypoventilation is as follows:[4][5][6]

  • Conditions causing high CO2 levels (hypercapnia) results in the body assuming that the O2 levels are low.
  • As a result, to increase the O2 supply the blood vessels in the brain dilate.

Causes

Following are the various causes of hyperventilation.

Life-Threatening Causes

Common Causes

Causes by Organ System

Cardiovascular Cheyne-stokes respirations, congestive cardiac failure, pulmonary embolism, stroke
Chemical/Poisoning Ammonium chloride, camphor , glycol ether , inhalation of irritants, methanol, salicylate poisoning
Dental No underlying causes
Dermatologic No underlying causes
Drug Side Effect Aminophylline, aspirin, coffee abuse, pralidoxime, tiagabine
Ear Nose Throat No underlying causes
Endocrine Diabetic ketoacidosis, renal disease
Environmental Acute stress disorder
Gastroenterologic Abdominal surgery, acute liver failure, acute porphyria, end stage liver failure, hepatic cirrhosis, intestinal fistula, pyloric stenosis
Genetic Acute porphyria, arginosuccinic aciduria, carbamoylphosphate synthetase 1 deficiency disease, carbonic anhydrase va deficiency, hereditary fructose-1,6-bisphosphatase deficiency, Pitt-hopkins syndrome
Hematologic Acute porphyria
Iatrogenic No underlying causes
Infectious Disease CNS infection, fever
Musculoskeletal/Orthopedic Hip cancer
Neurologic Altitude sickness, acute brain trauma, central neurogenic hyperventilation, cerebrovascular accident, CNS infection, Cree leukoencephalopathy, damaged respiratory pathways, epilepsy, epileptic encephalopathy, early infantile, 2; head injury, intracranial space-occupying lesion, meningoencephalitis, pain, Pitt-Hopkins syndrome, raised intracranial pressure, stroke, vasovagal attacks
Nutritional/Metabolic Diabetic ketoacidosis, hereditary fructose-1,6-bisphosphatase deficiency, heat stroke, lactic acidosis
Obstetric/Gynecologic No underlying causes
Oncologic Bronchial neoplasm, rib tumor
Ophthalmologic No underlying causes
Overdose/Toxicity Biguanide intolerance
Psychiatric Acute stress disorder, adult panic-anxiety syndrome, agoraphobia, anxiety, Briquet's syndrome, combat stress reaction, Cree leukoencephalopathy,crying or severe distress, Da Costa syndrome, depression, distress, excitement, fear, functional disorders, grief, hypochondriasis, hysteria, malingering, pain, panic attack, phobia, primary habit disorder, Rett's syndrome, schizophrenia, stress, strong emotions
Pulmonary Acute altitude sickness, apneustic respirations, asthma, ataxic respiration, biot's respiration, central neurogenic hyperventilation, Cheyne-stokes respirations, damaged respiratory pathways, diffuse pulmonary fibrosis, emphysema , hyperventilation syndrome, inhalation of irritants, lung damage, metabolic acidosis, persistent hypoxemia, pleural effusion, pneumonia, pneumothorax, pulmonary embolism, pulmonary oedema
Renal/Electrolyte Acid-base imbalance, metabolic acidosis, phaeochromocytoma, renal disease
Rheumatology/Immunology/Allergy Asthma, pseudoallergic reactions
Sexual No underlying causes
Trauma Brain trauma, head injury, lung damage, raised intracranial pressure, sponatneous pneumothorax, stroke, surgical relocation of ureters in ileum or colon
Urologic Surgical relocation of ureters in ileum or colon
Miscellaneous Abdominal surgery, adulation, childbirth, fever

Causes in Alphabetical Order

Differentiating Hyperventilation from other Diseases

Various diseases that can cause hyperventilation may include diseases of respiratory, cardiovascular, endocrine, central nervous system, and musculoskeletal system. Pregnancy, sepsis, and hepatic failure are other conditions that may also result in hyperventilation. Given below is a differential diagnosis of diseases presenting with hyperventilation.

Abbreviations: ABG (arterial blood gas); ACE (angiotensin converting enzyme); βhCG (beta human chorionic gonadotropin); BMP (basic metabolic panel); BNP (brain natriuretic peptide); CBC (complete blood count); COPD (chronic obstructive pulmonary disease); CSF (cerebrospinal fluid); CXR (chest X-ray); CT (computed tomography); DLCO (diffusing capacity of the lung for carbon monoxide); DOE (dyspnea on exercise); ECG (electrocardiogram); FEF (forced expiratory flow rate); FEV1 (forced expiratory volume); FT4 (free T4); FVC (forced vital capacity); HRCT (high resolution computed tomography); JVD (jugular vein distention); LFTs (liver function tests); MCV (mean corpuscular volume); MEN (multiple endocrine neoplasia); MRI (magnetic resonance imaging); P2 (pulmonic heart sound); Plt (platelet); PT (prothrombin time); RBC (red blood cell); RV (residual volume); SIADH (syndrome of inappropriate antidiuretic hormone); S3 ( third heart sound); S4 (fourth heart sound); T3 ((Triiodothyronine); TLC (total lung capacity); TSH (thyroid stimulating hormone); VC (vital capacity); VMA(vanillylmandelic acid); Vt (tidal volume); WBC (white blood cell);

Organ system Diseases Clinical manifestations Diagnosis Other features
Symptoms Physical exam
Chest pain Dyspnea Fever Palpitations Cyanosis Tachypnea JVD Peripheral edema Auscultation ABGs Lab findings Imaging PFT Gold standard
Pulmonary system Pneumothorax[7] + + +/- + +/- + - - +/- Hypoxemia - X- ray -

CT-scan -

  • bullae
Pulmonary embolism[8] +/- + +/- + +/- + +/- - Respiratory alkalosis
  • Normal
Pneumonia[9] +/- + + + +/- + - - +/- Hypoxemia
  • Normal
Exacerbation of asthma/COPD[10] +/- + +/- + + + - - +/- Hypoxemia
Interstitial lung disease[11][12] +/- + +/- + + + +/- - +/- Hypoxemia _
  • CXR- Reticular infiltrates
  • Honey combing
Intrapulmonary shunt[13] +/- + - - + +/- - - +/- Hypoxemia
Upper airway obstruction[14] - + - -/+ -/+ + -/+ - +/- Hypoxemia -
High altitude sickness[15][16][17] - + +/- + +/- + - + Respiratory alkalosis
  • EKG- Right sided heart strain
  • Test in a hypobaric chamber with and without supplemental O2-breathing
Cardiovascular system Acute coronary syndrome[18] + + - +/- +/- +/- +/- +/- - -
Heart failure[19] +/- + - +/- + +/- + + Respiratory alkalosis CXR shows
Dysrhythmias[18] +/- + - + - +/- - - Normal
  • Normal
  • Normal
Shock[20][21] +/- +/- +/- +/- +/- +/- +/- +/- Combined acid-base disorders are frequently encountered in different stages
Metabolic/Systemic disorders Diabetic ketoacidosis[22] - + +/- - - - - - Metabolic acidosis
  • Normal
  • Normal
Hypocalcemia[23][24] - + - + - +/- - - Respiratory alkalosis
  • Normal
  • Serum Ionized calcium
Hypoglycemia[25][26] - +/- - +/- - - - - Normal
  • Normal
  • 72-hour supervised fasting test
Endocrine system Hyperthyroidism[27][28] +/- + - +/- - +/- - - Variable
  • Normal
Pheochromocytoma[29][30] - + +/- + - +/- - -
  • Asymmetric chest expansion
Normal
  • Normal
CNS Central nervous system tumor[31][32] - +/- - - - +/- - -
  • Normal
Variable based on tumor location
  • Normal
Anxiety/panic attacks[33] +/- + - +/- - - - -
  • Normal
Normal
  • Normal
  • Normal
  • Normal
Others Pregnancy[34] +/- + - - - - - +/-
  • Normal
Respiratory alkalosis
  • Normal
Hepatic failure[35][36] - +/- +/- +/- +/- + + + +/- Respiratory alkalosis
  • Normal
Sepsis[37] - + +/- +/- - - - -
  • Normal
Variable based on the sepsis phase
  • Normal
  • Normal

References

  1. Kenneth Baillie and Alistair Simpson. [ttp://www.altitude.org/calculators/oxygencalculator/oxygencalculator.htm "Hyperventilation calculator"]. Apex (Altitude Physiology EXpeditions). Retrieved 2006-08-10. - Online interactive oxygen delivery calculator that mimicks hyperventilation
  2. Barrett, Kim (2012). "Chapter 34. Introduction to Pulmonary Structure and Mechanics". Ganong's review of medical physiology. New York London: McGraw-Hill Medical McGraw-Hill distributor. ISBN 978-0071780032.
  3. Engelking, Larry R. (2015). "Respiratory Alkalosis": 590–595. doi:10.1016/B978-0-12-391909-0.50091-8.
  4. Stocchetti N, Maas AI, Chieregato A, van der Plas AA (2005). "Hyperventilation in head injury: a review". Chest. 127 (5): 1812–27. doi:10.1378/chest.127.5.1812. PMID 15888864.
  5. Ainslie PN, Ashmead JC, Ide K, Morgan BJ, Poulin MJ (2005). "Differential responses to CO2 and sympathetic stimulation in the cerebral and femoral circulations in humans". J Physiol. 566 (Pt 2): 613–24. doi:10.1113/jphysiol.2005.087320. PMC 1464750. PMID 15890697.
  6. Battisti-Charbonney A, Fisher J, Duffin J (2011). "The cerebrovascular response to carbon dioxide in humans". J Physiol. 589 (Pt 12): 3039–48. doi:10.1113/jphysiol.2011.206052. PMC 3139085. PMID 21521758.
  7. Currie GP, Alluri R, Christie GL, Legge JS (2007). "Pneumothorax: an update". Postgrad Med J. 83 (981): 461–5. doi:10.1136/pgmj.2007.056978. PMC 2600088. PMID 17621614.
  8. Bĕlohlávek J, Dytrych V, Linhart A (2013). "Pulmonary embolism, part I: Epidemiology, risk factors and risk stratification, pathophysiology, clinical presentation, diagnosis and nonthrombotic pulmonary embolism". Exp Clin Cardiol. 18 (2): 129–38. PMC 3718593. PMID 23940438.
  9. Simonetti AF, Viasus D, Garcia-Vidal C, Carratalà J (2014). "Management of community-acquired pneumonia in older adults". Ther Adv Infect Dis. 2 (1): 3–16. doi:10.1177/2049936113518041. PMC 4072047. PMID 25165554.
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  13. Vodoz JF, Cottin V, Glérant JC, Derumeaux G, Khouatra C, Blanchet AS; et al. (2009). "Right-to-left shunt with hypoxemia in pulmonary hypertension". BMC Cardiovasc Disord. 9: 15. doi:10.1186/1471-2261-9-15. PMC 2671488. PMID 19335916.
  14. Darras KE, Roston AT, Yewchuk LK (2015). "Imaging Acute Airway Obstruction in Infants and Children". Radiographics. 35 (7): 2064–79. doi:10.1148/rg.2015150096. PMID 26495798.
  15. Basnyat B, Murdoch DR (2003). "High-altitude illness". Lancet. 361 (9373): 1967–74. doi:10.1016/S0140-6736(03)13591-X. PMID 12801752.
  16. Schoene RB (2008). "Illnesses at high altitude". Chest. 134 (2): 402–416. doi:10.1378/chest.07-0561. PMID 18682459.
  17. Stream JO, Grissom CK (2008). "Update on high-altitude pulmonary edema: pathogenesis, prevention, and treatment". Wilderness Environ Med. 19 (4): 293–303. doi:10.1580/07-WEME-REV-173.1. PMID 19099331.
  18. 18.0 18.1 Bruyninckx R, Aertgeerts B, Bruyninckx P, Buntinx F (2008). "Signs and symptoms in diagnosing acute myocardial infarction and acute coronary syndrome: a diagnostic meta-analysis". Br J Gen Pract. 58 (547): 105–11. doi:10.3399/bjgp08X277014. PMC 2233977. PMID 18307844.
  19. Gaggin, Hanna K.; Januzzi, James L. (2013). "Biomarkers and diagnostics in heart failure". Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. 1832 (12): 2442–2450. doi:10.1016/j.bbadis.2012.12.014. ISSN 0925-4439.
  20. Churpek MM, Zadravecz FJ, Winslow C, Howell MD, Edelson DP (2015). "Incidence and Prognostic Value of the Systemic Inflammatory Response Syndrome and Organ Dysfunctions in Ward Patients". Am J Respir Crit Care Med. 192 (8): 958–64. doi:10.1164/rccm.201502-0275OC. PMC 4642209. PMID 26158402.
  21. Kelly AM, Kyle E, McAlpine R (2002). "Venous pCO(2) and pH can be used to screen for significant hypercarbia in emergency patients with acute respiratory disease". J Emerg Med. 22 (1): 15–9. PMID 11809551.
  22. Westerberg DP (2013). "Diabetic ketoacidosis: evaluation and treatment". Am Fam Physician. 87 (5): 337–46. PMID 23547550.
  23. Tohme JF, Bilezikian JP (1993). "Hypocalcemic emergencies". Endocrinol Metab Clin North Am. 22 (2): 363–75. PMID 8325292.
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  25. Hepburn DA, Deary IJ, Frier BM, Patrick AW, Quinn JD, Fisher BM (1991). "Symptoms of acute insulin-induced hypoglycemia in humans with and without IDDM. Factor-analysis approach". Diabetes Care. 14 (11): 949–57. PMID 1797507.
  26. Towler DA, Havlin CE, Craft S, Cryer P (1993). "Mechanism of awareness of hypoglycemia. Perception of neurogenic (predominantly cholinergic) rather than neuroglycopenic symptoms". Diabetes. 42 (12): 1791–8. PMID 8243825.
  27. Iglesias P, Acosta M, Sánchez R, Fernández-Reyes MJ, Mon C, Díez JJ (2005). "Ambulatory blood pressure monitoring in patients with hyperthyroidism before and after control of thyroid function". Clin Endocrinol (Oxf). 63 (1): 66–72. doi:10.1111/j.1365-2265.2005.02301.x. PMID 15963064.
  28. Forfar JC, Muir AL, Sawers SA, Toft AD (1982). "Abnormal left ventricular function in hyperthyroidism: evidence for a possible reversible cardiomyopathy". N Engl J Med. 307 (19): 1165–70. doi:10.1056/NEJM198211043071901. PMID 7121544.
  29. Neumann HP, Pawlu C, Peczkowska M, Bausch B, McWhinney SR, Muresan M; et al. (2004). "Distinct clinical features of paraganglioma syndromes associated with SDHB and SDHD gene mutations". JAMA. 292 (8): 943–51. doi:10.1001/jama.292.8.943. PMID 15328326.
  30. Bravo EL (1991). "Pheochromocytoma: new concepts and future trends". Kidney Int. 40 (3): 544–56. PMID 1787652.
  31. Forsyth PA, Posner JB (1993). "Headaches in patients with brain tumors: a study of 111 patients". Neurology. 43 (9): 1678–83. PMID 8414011.
  32. Valentinis L, Tuniz F, Valent F, Mucchiut M, Little D, Skrap M; et al. (2010). "Headache attributed to intracranial tumours: a prospective cohort study". Cephalalgia. 30 (4): 389–98. doi:10.1111/j.1468-2982.2009.01970.x. PMID 19673912.
  33. Taylor CB (2006). "Panic disorder". BMJ. 332 (7547): 951–5. doi:10.1136/bmj.332.7547.951. PMC 1444835. PMID 16627512.
  34. Lee SY, Chien DK, Huang CH, Shih SC, Lee WC, Chang WH (2017). "Dyspnea in pregnancy". Taiwan J Obstet Gynecol. 56 (4): 432–436. doi:10.1016/j.tjog.2017.04.035. PMID 28805596.
  35. Lee WM (1993). "Acute liver failure". N Engl J Med. 329 (25): 1862–72. doi:10.1056/NEJM199312163292508. PMID 8305063.
  36. Gill RQ, Sterling RK (2001). "Acute liver failure". J Clin Gastroenterol. 33 (3): 191–8. PMID 11500606.
  37. Askim Å, Mehl A, Paulsen J, DeWan AT, Vestrheim DF, Åsvold BO; et al. (2016). "Epidemiology and outcome of sepsis in adult patients with Streptococcus pneumoniae infection in a Norwegian county 1993-2011: an observational study". BMC Infect Dis. 16: 223. doi:10.1186/s12879-016-1553-8. PMC 4877975. PMID 27216810.

See also

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