Bronchitis laboratory tests: Difference between revisions

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{{CMG}}
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{{CMG}}{{AE}}{{MehdiP}}; {{NRM}}
{{Bronchitis}}
{{Bronchitis}}
==Overview==
==Overview==
'''Bronchitis''' is an [[inflammation]] of the [[bronchus|bronchi]] (medium-size airways) in the [[lung]]s. ''[[Acute bronchitis]]'' is usually caused by [[virus]]es or [[bacteria]] and may present as cough with sputum that last several days or weeks (10 days). Other symptoms like shortness of breath, chest discomfort, and sore throat can also be found. '''Chronic bronchitis''' is not necessarily caused by infection and is generally part of a syndrome called [[chronic obstructive pulmonary disease]] (COPD); it is defined clinically as a persistent [[cough]] that produces [[sputum]] (phlegm) and mucus, for at least three months in two consecutive years. In late stages, the disease may present with blue discoloration of body ([[cyanosis]]) and difficulty in breathing ([[dyspnea]]).
Diagnostic tests are rarely needed to confirm the diagnosis of [[acute bronchitis]]. In very specific conditions, serologic tests, viral cultures or sputum analyses may be performed. Generally, inflammatory markers, such as [[CRP|C-reactive protein]], rise during the course of acute bronchitis. [[Chronic bronchitis]] is diagnosed by definition, although there are some laboratory findings as the disease advances and causes complications.
 
==Laboratory Findings==
==Antigen testing and Serological markers==
===Acute Bronchitis===
Rapid antigen and serological tests have limited availability and are costly. However, it can be used to as an adjunct to diagnosis in certain conditions like:
Viral cultures, serologic assays, and sputum analyses may be performed when a potentially treatable infection is thought to be circulating or because of epidemiological purposes.<ref name="pmid17108344">{{cite journal |vauthors=Wenzel RP, Fowler AA |title=Clinical practice. Acute bronchitis |journal=N. Engl. J. Med. |volume=355 |issue=20 |pages=2125–30 |year=2006 |pmid=17108344 |doi=10.1056/NEJMcp061493 |url=}}</ref>
* The suspected organism is treatable
:'''Serologic assays'''
* A epidemic with the pathogen is suspected (influenza).
::[[Nasopharyngeal]] swab and aspirates to test for [[PCR]] are available but not widely used.<ref name="pmid17108344">{{cite journal |vauthors=Wenzel RP, Fowler AA |title=Clinical practice. Acute bronchitis |journal=N. Engl. J. Med. |volume=355 |issue=20 |pages=2125–30 |year=2006 |pmid=17108344 |doi=10.1056/NEJMcp061493 |url=}}</ref>
* Patient has typical presentation suggestive of pathogen. the infection is known to be circulating in the community, and the patient has suggestive symptoms or signs (e.g., testing for influenza during influenza season in patients with cough and fever)
:'''Procalcitonin'''
Other tests
::[[Procalcitonin]] level is helpful to distinguish bacterial from other causes of inflammation. During bacterial infections, the level of procalcitonin will rise over 0.25 mg/L and indicates prescription of antibiotics.<ref name="pmid19738090">{{cite journal |vauthors=Schuetz P, Christ-Crain M, Thomann R, Falconnier C, Wolbers M, Widmer I, Neidert S, Fricker T, Blum C, Schild U, Regez K, Schoenenberger R, Henzen C, Bregenzer T, Hoess C, Krause M, Bucher HC, Zimmerli W, Mueller B |title=Effect of procalcitonin-based guidelines vs standard guidelines on antibiotic use in lower respiratory tract infections: the ProHOSP randomized controlled trial |journal=JAMA |volume=302 |issue=10 |pages=1059–66 |year=2009 |pmid=19738090 |doi=10.1001/jama.2009.1297 |url=}}</ref><ref name="pmid18852401">{{cite journal |vauthors=Briel M, Schuetz P, Mueller B, Young J, Schild U, Nusbaumer C, Périat P, Bucher HC, Christ-Crain M |title=Procalcitonin-guided antibiotic use vs a standard approach for acute respiratory tract infections in primary care |journal=Arch. Intern. Med. |volume=168 |issue=18 |pages=2000–7; discussion 2007–8 |year=2008 |pmid=18852401 |doi=10.1001/archinte.168.18.2000 |url=}}</ref><ref name="pmid21460294">{{cite journal |vauthors=Gilbert DN |title=Procalcitonin as a biomarker in respiratory tract infection |journal=Clin. Infect. Dis. |volume=52 Suppl 4 |issue= |pages=S346–50 |year=2011 |pmid=21460294 |doi=10.1093/cid/cir050 |url=}}</ref>
* A sputum sample showing [[neutrophil granulocyte]]s (inflammatory white blood cells) and [[microbiological culture|culture]]
===Chronic Bronchitis===
* A [[blood test]] would indicate inflammation (as indicated by a raised [[white blood cell]] count and elevated [[C-reactive protein]]).
:'''Pulse Oximetry'''
* Damage caused by irritation of the airways leads to inflammation and leads to neutrophils being present
::* Although [[pulse oximetry]] is not as accurate in predicting the percent [[oxygen saturation]] as [[arterial blood gas]] analysis, it gives a quick estimate of patient status when considered with the clinical status.
* A [[chest X-ray]] that reveals hyperinflation; collapse and consolidation of lung areas would support a diagnosis of [[pneumonia]]. Some conditions that predispose to bronchitis may be indicated by chest radiography.
:'''Arterial Blood Gas (ABG)'''
::* [[Arterial blood gas|ABG]] may show changes of [[hypoxemia]] and [[hypercapnia]] depending on the severity of disease.
:'''Hematocrit'''
::* COPD patients may have hypoxemia due to the chronic underlying disease. This chronic hypoxemia may lead to [[polycythemia]].
::** [[Hematocrit]] > 55% in men or 50% in women is diagnostic of polycythemia.
:'''Culture'''
::* A [[sputum]] sample showing [[neutrophil granulocyte]]s and [[microbiological culture|culture]] showing pathogenic microorganisms such as [[Streptococcus|Streptococcus spp.]]
:'''Alpha 1 Antitrypsin Levels'''<ref name="pmid14522813">{{cite journal |vauthors= |title=American Thoracic Society/European Respiratory Society statement: standards for the diagnosis and management of individuals with alpha-1 antitrypsin deficiency |journal=Am. J. Respir. Crit. Care Med. |volume=168 |issue=7 |pages=818–900 |year=2003 |pmid=14522813 |doi=10.1164/rccm.168.7.818 |url=}}</ref>
::* Serum [[alpha 1 antitrypsin]] levels below the protective threshold value (i.e. 3-7 mmol/L) may lead to a severe form of [[emphysema]]
::* 95% cases are due to the severe variant the Z allele present in these patients.
::* Specific phenotyping, and [[genetic]] counseling is reserved for patients in whom serum levels are 7-11 mmol/L.


==References==
==References==
{{Reflist|2}}
{{Reflist|2}}
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[[Category:Inflammations]]
[[Category:Pulmonology]]
[[Category:General practice]]

Latest revision as of 20:44, 29 July 2020

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2]; Nate Michalak, B.A.

Bronchitis Main page

Patient Information

Overview

Causes

Classification

Acute bronchitis
Chronic bronchitis

Differential Diagnosis

Overview

Diagnostic tests are rarely needed to confirm the diagnosis of acute bronchitis. In very specific conditions, serologic tests, viral cultures or sputum analyses may be performed. Generally, inflammatory markers, such as C-reactive protein, rise during the course of acute bronchitis. Chronic bronchitis is diagnosed by definition, although there are some laboratory findings as the disease advances and causes complications.

Laboratory Findings

Acute Bronchitis

Viral cultures, serologic assays, and sputum analyses may be performed when a potentially treatable infection is thought to be circulating or because of epidemiological purposes.[1]

Serologic assays
Nasopharyngeal swab and aspirates to test for PCR are available but not widely used.[1]
Procalcitonin
Procalcitonin level is helpful to distinguish bacterial from other causes of inflammation. During bacterial infections, the level of procalcitonin will rise over 0.25 mg/L and indicates prescription of antibiotics.[2][3][4]

Chronic Bronchitis

Pulse Oximetry
Arterial Blood Gas (ABG)
Hematocrit
  • COPD patients may have hypoxemia due to the chronic underlying disease. This chronic hypoxemia may lead to polycythemia.
    • Hematocrit > 55% in men or 50% in women is diagnostic of polycythemia.
Culture
Alpha 1 Antitrypsin Levels[5]
  • Serum alpha 1 antitrypsin levels below the protective threshold value (i.e. 3-7 mmol/L) may lead to a severe form of emphysema
  • 95% cases are due to the severe variant the Z allele present in these patients.
  • Specific phenotyping, and genetic counseling is reserved for patients in whom serum levels are 7-11 mmol/L.

References

  1. ↑ 1.0 1.1 Wenzel RP, Fowler AA (2006). "Clinical practice. Acute bronchitis". N. Engl. J. Med. 355 (20): 2125–30. doi:10.1056/NEJMcp061493. PMID 17108344.
  2. ↑ Schuetz P, Christ-Crain M, Thomann R, Falconnier C, Wolbers M, Widmer I, Neidert S, Fricker T, Blum C, Schild U, Regez K, Schoenenberger R, Henzen C, Bregenzer T, Hoess C, Krause M, Bucher HC, Zimmerli W, Mueller B (2009). "Effect of procalcitonin-based guidelines vs standard guidelines on antibiotic use in lower respiratory tract infections: the ProHOSP randomized controlled trial". JAMA. 302 (10): 1059–66. doi:10.1001/jama.2009.1297. PMID 19738090.
  3. ↑ Briel M, Schuetz P, Mueller B, Young J, Schild U, Nusbaumer C, Périat P, Bucher HC, Christ-Crain M (2008). "Procalcitonin-guided antibiotic use vs a standard approach for acute respiratory tract infections in primary care". Arch. Intern. Med. 168 (18): 2000–7, discussion 2007–8. doi:10.1001/archinte.168.18.2000. PMID 18852401.
  4. ↑ Gilbert DN (2011). "Procalcitonin as a biomarker in respiratory tract infection". Clin. Infect. Dis. 52 Suppl 4: S346–50. doi:10.1093/cid/cir050. PMID 21460294.
  5. ↑ "American Thoracic Society/European Respiratory Society statement: standards for the diagnosis and management of individuals with alpha-1 antitrypsin deficiency". Am. J. Respir. Crit. Care Med. 168 (7): 818–900. 2003. doi:10.1164/rccm.168.7.818. PMID 14522813.

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