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| | {| class="infobox" style="float:right;" |
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| | | [[File:Siren.gif|30px|link=Altered mental status resident survival guide]]|| <br> || <br> |
| | | [[Altered mental status resident survival guide|'''Resident'''<br>'''Survival'''<br>'''Guide''']] |
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| {{Altered mental status}} | | {{Altered mental status}} |
| {{CMG}}; {{AE}} {{PB}} | | {{CMG}}; {{AE}} {{PB}} |
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| [[Category:Emergency medicine]]
| | ==References== |
| | {{Reflist|2}} |
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| [[Category:Neurology]] | | [[Category:Neurology]] |
| | [[Category:Psychiatry]] |
| [[Category:Intensive care medicine]] | | [[Category:Intensive care medicine]] |
| [[Category:Up-To-Date]]
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| {{WikiDoc Help Menu}} | | {{WikiDoc Help Menu}} |
| {{WikiDoc Sources}} | | {{WikiDoc Sources}} |
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| An '''altered level of consciousness''' is any measure of arousal other than normal. Level of consciousness ('''LOC''') is a measure of a person's [[arousal|arousability]] and responsiveness to [[Stimulus (physiology)|stimuli]] from the environment.<ref name="Kandel00">
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| {{cite book |author=Kandel ER, Jessell, Thomas M.; Schwartz, James H. |title=Principles of neural science |publisher=McGraw-Hill |location=New York |year=2000 |pages=901 |isbn=0-8385-7701-6 |oclc= |doi= |accessdate=2008-07-03 |url = http://books.google.com/?id=yzEFK7Xc87YC&pg=PA901&dq=%22level+of+consciousness%22}}</ref> A mildly depressed level of [[consciousness]] or [[alertness]] may be classed as [[lethargy]]; someone in this state can be aroused with little difficulty.<ref name="Kandel00"/> People who are [[Obtundation|obtunded]] have a more depressed level of consciousness and cannot be fully aroused.<ref name="Kandel00"/><ref name="Porth07"/> Those who are not able to be aroused from a sleep-like state are said to be [[stupor]]ous.<ref name="Kandel00"/><ref name="Porth07"/> [[Coma]] is the inability to make any purposeful response.<ref name="Kandel00"/><ref name="Porth07"/> Scales such as the [[Glasgow coma scale]] have been designed to measure the level of consciousness.
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| An altered level of consciousness can result from a variety of factors, including alterations in the chemical environment of the brain (e.g. exposure to [[poison]]s or [[intoxicant]]s), insufficient [[oxygen]] or [[blood flow]] in the brain, and excessive [[intracranial pressure|pressure within the skull]]. <!--Level of consciousness may decline abruptly or slowly, or it may increase and decrease intermittently.<ref name="Dohert05"/>--> Prolonged unconsciousness is understood to be a sign of a [[medical emergency]].<ref name="Pollak02"/> A deficit in the level of consciousness suggests that both of the [[cerebral hemisphere]]s or the [[reticular activating system]] have been injured.<ref name="Porth071">Porth, p. 838</ref> A decreased level of consciousness correlates to increased morbidity ([[disability]]) and [[mortality rate|mortality]] (death).<ref name="Scheld041">Scheld ''et al.''. p. 530</ref> Thus it is a valuable measure of a patient's medical and neurological status. In fact, some sources consider level of consciousness to be one of the [[vital sign]]s.<ref name="Pollak02"/><ref name="Forgey99">
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| {{
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| cite book |author=Forgey WW |title=Wilderness Medicine, Beyond First Aid, 5th Edition |publisher=Globe Pequot |location=Guilford, Conn |year=1999 |pages =13 |isbn=0-7627-0490-X |oclc= |doi= |accessdate= 2008-07-04 |url = http://books.google.com/?id=UNwzDUy9AlsC&pg=PA13&dq=%22level+of+consciousness%22
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| }}
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| </ref>
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| ==Definition==
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| Scales and terms to classify the levels of consciousness differ, but in general, reduction in response to stimuli indicates an altered level of consciousness:
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| {| class="wikitable"
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| |+ '''Levels of consciousness'''
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| ! Level !! Summary (Kruse)<ref name="Porth07"/> !! Description
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| ! [[Conscious]]
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| | Normal
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| | Assessment of LOC involves checking [[Orientation (mental)|orientation]]: people who are able promptly and spontaneously to state their name, location, and the date or time are said to be oriented to self, place, and time, or "oriented X3".<ref name="Kruse86">
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| {{
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| cite book |author=Kruse MJ |title=Nursing the Neurological and Neurotrauma Patient |publisher=Rowman & Allanheld |location=Totowa, N.J |year=1986 |pages= 57–58 |isbn=0-8476-7451-7 |oclc= |doi= |accessdate=
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| |url= http://books.google.com/?id=3BN3d2Ps8HAC&pg=PA57&dq=%22level+of+consciousness%22#PPA58,M1
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| }}
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| </ref> A normal [[sleep]] stage from which a person is easily awakened is also considered a normal level of consciousness.<ref name="Tindall90"/> "Clouding of consciousness" is a term for a mild alteration of consciousness with alterations in attention and wakefulness.<ref name="Tindall90"/>
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| ! [[Confused]]
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| |Disoriented; impaired thinking and responses
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| | People who do not respond quickly with information about their name, location, and the time are considered "obtuse" or "[[confusion|confused]]".<ref name="Kruse86"/> A confused person may be bewildered, disoriented, and have difficulty following instructions.<ref name="Tindall90"/> The person may have slow thinking and possible memory time loss. This could be caused by sleep deprivation, malnutrition, allergies, environmental pollution, drugs (prescription and nonprescription), and infection.
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| ![[Delirium|Delirious]]
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| |Disoriented; restlessness, hallucinations, sometimes delusions
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| |Some scales have "delirious" below this level, in which a person may be restless or agitated and exhibit a marked deficit in [[attention]].<ref name="Porth07"/>
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| ![[somnolence|Somnolent]]
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| | Sleepy
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| | A ''[[somnolence|somnolent]]''<!--obtunded--> person shows excessive [[drowsiness]] and responds to stimuli only with incoherent mumbles or disorganized movements.<ref name="Kruse86"/>
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| ![[Obtunded]]
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| |Decreased alertness; slowed psychomotor responses
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| | In ''[[obtundation]]'', a person has a decreased interest in their surroundings, slowed responses, and sleepiness.<ref name="Tindall90"/>
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| |-
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| ![[Stuporous]]
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| | Sleep-like state (not unconscious); little/no spontaneous activity
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| |People with an even lower level of consciousness, stupor, only respond by [[Facial expression|grimacing]] or drawing away from painful stimuli.<ref name="Kruse86"/>
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| ![[Coma]]tose
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| | Cannot be aroused; no response to stimuli
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| | Comatose people do not even make this response to stimuli, have no [[corneal reflex|corneal]] or [[gag reflex]], and they may have no [[pupillary response]] to light.<ref name="Kruse86"/>
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| |}
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| ===Glasgow Coma Scale===
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| {{Main|Glasgow Coma Scale}}
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| The most commonly used tool for measuring LOC objectively is the [[Glasgow Coma Scale]] (GCS). It has come into almost universal use for assessing people with [[Acquired brain injury|brain injury]],<ref name="Porth07">{{cite book |author=Porth C |title=Essentials of Pahtophysiology: Concepts of Altered Health States |publisher=Lippincott Williams & Wilkins |location=Hagerstown, MD |year=2007 |pages=835 |isbn=0-7817-7087-4 |oclc= |doi= |accessdate=2008-07-03 |url= http://books.google.com/?id=57RQC-3OPtUC&pg=PT858&dq=%22level+of+consciousness%22}}</ref> or an altered level of consciousness. Verbal, motor, and eye-opening responses to stimuli are measured, scored, and added into a final score on a scale of 3–15, with a lower score being a more decreased level of consciousness.
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| ===Others===
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| The [[AVPU]] scale is another means of measuring LOC: people are assessed to determine whether they are '''a'''lert, responsive to '''v'''erbal stimuli, responsive to '''p'''ainful stimuli, or '''u'''nresponsive.<ref name="Pollak02"/><ref name="Forgey99"/> To determine responsiveness to voice, a caregiver speaks to, or, failing that, yells at the person.<ref name="Pollak02"/> Responsiveness to pain is determined with a mild painful stimulus such as a pinch; moaning or withdrawal from the stimulus is considered a response to pain.<ref name="Pollak02"/> The ACDU scale, like AVPU, is easier to use than the GCS and produces similarly accurate results.<ref name="Posner07">{{cite book |author= Posner JB, Saper CB, Schiff ND, Plum F |title=Plum and Posner's Diagnosis of Stupor and Coma |publisher=Oxford University Press, USA |location= |year=2007 |pages=41 |isbn=0-19-532131-6 |oclc= |doi= |accessdate=}}</ref> Using ACDU, a patient is assessed for '''a'''lertness, '''c'''onfusion, '''d'''rowsiness, and '''u'''nresponsiveness.<ref name="Posner07"/>
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| The [[Grady Coma Scale]] classes people on a scale of I to V along a scale of confusion, stupor, deep stupor, [[abnormal posturing]], and coma.<ref name="Tindall90"/>
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| ==Differential diagnosis==
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| A lowered level of consciousness indicate a deficit in brain function.<ref name="Porth071" /> Level of consciousness can be lowered when the brain receives insufficient oxygen (as occurs in [[hypoxia (medical)|hypoxia]]); insufficient blood (as occurs in [[shock (circulatory)|shock]]); or has an alteration in the [[brain chemistry|brain's chemistry]].<ref name="Pollak02">{{cite book |author= Pollak AN, Gupton CL |title=Emergency Care and Transportation of the Sick and Injured |publisher=Jones and Bartlett |location=Boston |year=2002 |pages=140 |isbn=0-7637-1666-9 |oclc= |doi= |accessdate=2008-07-04 |url=http://books.google.com/?id=xAPuKkKA6FEC&pg=PT177&dq=%22level+of+consciousness%22}}</ref> [[Metabolic disorder]]s such as [[diabetes mellitus]] and [[uremia]] can alter consciousness.<ref name="Dohert05"/> [[hyponatremia|Hypo-]] or [[hypernatremia]] (decreased and elevated levels of [[sodium]], respectively) as well as [[dehydration]] can also produce an altered LOC.<ref name="Johnson98">
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| {{cite book |author=Johnson AF, Jacobson BH |title=Medical Speech-language Pathology: A Practitioner's Guide |publisher=Thieme |location=Stuttgart |year=1998 |pages=142 |isbn=0-86577-688-1 |oclc= |doi= |accessdate=2008-07-04 |url= http://books.google.com/?id=Vo5cPaOEG_4C&pg=PA142&vq=level+of+consciousness&dq=%22level+of+consciousness%22}}</ref> A [[pH]] outside of the range the brain can tolerate will also alter LOC.<ref name="Tindall90">{{cite book |author=Tindall SC |editor=Walker HK, Hall WD, Hurst JW |chapter= Level of consciousness |title= Clinical Methods: The History, Physical, and Laboratory Examinations|publisher=Butterworth Publishers |location=|year=1990 |pages= |isbn=|oclc=|doi= |accessdate=2008-07-04 |url= http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&partid=380}}</ref> Exposure to [[drug]]s (e.g. [[alcohol]]) or [[toxin]]s may also lower LOC,<ref name="Pollak02"/> as may a [[core temperature]] that is too high or too low ([[hyperthermia]] or [[hypothermia]]). Increases in [[intracranial pressure]] (the pressure within the skull) can also cause altered LOC. It can result from [[traumatic brain injury]] such as [[concussion]].<ref name="Dohert05"/> [[Stroke]] and [[intracranial hemorrhage]] are other causes.<ref name="Dohert05"/> [[Infection]]s of the [[central nervous system]] may also be associated with decreased LOC; for example, an altered LOC is the most common symptom of [[encephalitis]].<ref name="Scheld04">
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| {{cite book |author= Scheld WM, Whitley RJ, Marra CM |title=Infections of the Central Nervous System |publisher=Lippincott Williams & Wilkins |location=Hagerstown, MD |year=2004 |pages= 219|isbn=0-7817-4327-3 |oclc= |doi= |accessdate=2008-07-04 |url = http://books.google.com/?id=jjvFj6aQeMgC&pg=PA530&dq=%22level+of+consciousness%22#PPA530,M1}}</ref> [[Neoplasm]]s within the [[intracranial cavity]] can also affect consciousness,<ref name="Dohert05"/> as can [[epilepsy]] and [[Postictal state|post-seizure state]]s.<ref name="Tindall90"/> A decreased LOC can also result from a combination of factors.<ref name="Dohert05"/> | |
| A [[concussion]], which is a mild traumatic brain injury (MTBI) may result in decreased LOC.
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| ==Pathophysiology==
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| Although the neural science behind alertness, wakefulness, and arousal are not fully known, the [[reticular formation]] is known to play a role in these.<ref name="Tindall90"/> The [[ascending reticular activating system]] is a postulated group of neural connections that receives sensory input and projects to the [[cerebral cortex]] through the [[midbrain]] and [[thalamus]] from the retucular formation.<ref name="Tindall90"/> Since this system is thought to modulate wakefulness and sleep, interference with it, such as injury, illness, or metabolic disturbances, could alter the level of consciousness.<ref name="Tindall90"/>
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| Normally, stupor and coma are produced by interference with the [[brain stem]], such as can be caused by a [[lesion]] or indirect effects, such as [[brain herniation]].<ref name="Tindall90"/> Mass lesions in the brain stem normally cause coma due to their effects on the reticular formation.<ref name="Tindall901">
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| {{ | |
| cite book |quote=Mass lesions within the brainstem produce coma by virtue of direct effects on the reticular formation |author=Tindall SC |editor=Walker HK, Hall WD, Hurst JW |chapter= Level of consciousness |title= Clinical Methods: The History, Physical, and Laboratory Examinations
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| |publisher=Butterworth Publishers |location=|year=1990 |pages= |isbn= |oclc= |doi= |accessdate=2008-07-04 |url= http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&partid=380
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| }} | |
| </ref> Mass [[lesion]]s that occur [[supratentorial|above]] the [[tentorium cerebelli]] (pictured) normally do not significantly alter the level of consciousness unless they are very large or affect both [[cerebral hemisphere]]s.<ref name="Tindall90"/>
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| ==Diagnostic approach==
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| Assessing LOC involves determining an individual's response to external stimuli.<ref name="Dohert05">
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| {{
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| cite book |author=von Koch CS, Hoff JT|chapter= Diagnosis and management of depressed states of consciousness |editor=Doherty GM |title=Current Surgical Diagnosis and Treatment |publisher=McGraw-Hill Medical |location= |year=2005 |pages= 863 |isbn=0-07-142315-X |oclc= |doi= |accessdate=2008-07-04 |url= http://books.google.com/?id=c3I-PFkMN2YC&pg=PA863&dq=%22level+of+consciousness%22
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| }}
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| </ref> Speed and accuracy of responses to questions and reactions to stimuli such as touch and pain are noted.<ref name="Dohert05"/> [[Reflex]]es, such as the [[coughing|cough]] and gag reflexes, are also means of judging LOC.<ref name="Dohert05"/> Once the level of consciousness is determined, clinicians seek clues for the cause of any alteration.<ref name="Tindall90"/> Usually the first tests in the ER are pulse oximetry to determine if there is hypoxia, serum glucose levels to rule out hypoglycemia. A urine drug screen may be sent. A CT head is very important to obtain to rule out bleed. In case, meningitis is suspected, a lumbar puncture must be performed. A serum TSH is an important test to order. In select groups consider vitamin B12 levels. Checking serum ammonia is not advised.{{Citation needed|date=August 2010}}
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| ==Treatment==
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| Treatment depends on the degree of decrease in consciousness and its underlying cause. Initial treatment often involves the administration of [[dextrose]] if the blood sugar is low as well as the administration of [[naloxone]] and [[thiamine]].
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| ==See also==
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| *[[Altered state of consciousness]]
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| *[[Disorders of consciousness]]
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| *[[Level of consciousness (esotericism)]]
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| ==References==
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| {{Reflist|2}}
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| {{Cognition, perception, emotional state and behaviour symptoms and signs}}
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| {{DEFAULTSORT:Altered Level Of Consciousness}}
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| [[Category:Neuroscience]]
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| [[Category:Neurological disorders]]
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| [[Category:Intensive care medicine]]
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| [[Category:Emergency medicine]]
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| [[Category:Central nervous system]]
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