Legionellosis laboratory findings: Difference between revisions
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{{Legionellosis}} | {{Legionellosis}} | ||
{{CMG}} | {{CMG}} | ||
==Overview== | |||
Laboratory abnormalities in Legionnaries' disease include leukocytosis with relative lymphopenia, hyponatremia, hypophosphatemia, and elevated levels of AST/ALT, CPK, ESR, CRP, LDH, and ferritin. Urine antigen testing in the first-line diagnostic method. Culture of the lower respiratory secretion is the gold standard for detecting Legionnaires' disease. | |||
==Laboratory Findings== | ==Laboratory Findings== | ||
Laboratory findings of Legionnaires' disease include:<ref>{{Cite journal| doi = 10.1016/j.idc.2009.10.014| issn = 1557-9824| volume = 24| issue = 1| pages = 73–105| last = Cunha| first = Burke A.| title = Legionnaires' disease: clinical differentiation from typical and other atypical pneumonias| journal = Infectious Disease Clinics of North America| date = 2010-03| pmid = 20171547}}</ref> | |||
* | * Leukocytosis | ||
* | * Lymphopenia | ||
* | * Hyponatremia | ||
* | * Hypophosphatemia | ||
* Elevated AST and ALT | |||
* Elevated CPK | |||
* Elevated ESR and CRP | |||
* Elevated LDH | |||
* Elevated ferritin | |||
==Diagnostic Studies== | ==Diagnostic Studies== | ||
===Microscopy=== | |||
* | |||
Legionella pneumophila are small, Gram-negative coccabacilli which may be difficult to detect in specimens by Gram staining.<ref>{{cite book | last = Versalovic | first = James | title = Manual of clinical microbiology | publisher = ASM Press | location = Washington, DC | year = 2011 | isbn = 978-1555814632 }}</ref> The organism can also be detected by immunofluorescent microscopy with the use of direct fluorescent antibody. | |||
===Urine Antigen Test=== | |||
The detection of soluble antigens (a component of the cell wall lipopolysaccharide) in the urine is the first-line diagnostic technique. The method is most accurate for detecting Lp1 MAb 3/1 subtypes. Sensitivity ranges from 56–99% and is lower in nosocomial infection and immunocompromised hosts.<ref>{{Cite journal| issn = 0095-1137| volume = 41| issue = 2| pages = 838–840| last1 = Helbig| first1 = Jürgen H.| last2 = Uldum| first2 = Søren A.| last3 = Bernander| first3 = Sverker| last4 = Lück| first4 = Paul Christian| last5 = Wewalka| first5 = Günther| last6 = Abraham| first6 = Bill| last7 = Gaia| first7 = Valeria| last8 = Harrison| first8 = Timothy G.| title = Clinical utility of urinary antigen detection for diagnosis of community-acquired, travel-associated, and nosocomial legionnaires' disease| journal = Journal of Clinical Microbiology| date = 2003-02| pmid = 12574296| pmc = PMC149701}}</ref> Urine antigen test may also be positive for Pontiac fever. IDSA/ATS guidelines recommend urinary antigen test for the following patients:<ref>{{Cite journal| doi = 10.1086/511159| issn = 1537-6591| volume = 44 Suppl 2| pages = –27-72| last1 = Mandell| first1 = Lionel A.| last2 = Wunderink| first2 = Richard G.| last3 = Anzueto| first3 = Antonio| last4 = Bartlett| first4 = John G.| last5 = Campbell| first5 = G. Douglas| last6 = Dean| first6 = Nathan C.| last7 = Dowell| first7 = Scott F.| last8 = File| first8 = Thomas M.| last9 = Musher| first9 = Daniel M.| last10 = Niederman| first10 = Michael S.| last11 = Torres| first11 = Antonio| last12 = Whitney| first12 = Cynthia G.| last13 = Infectious Diseases Society of America| last14 = American Thoracic Society| title = Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults| journal = Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America| date = 2007-03-01| pmid = 17278083}}</ref> | |||
* Unresponsive to outpatient antibiotic therapy | |||
* Severe pneumonia especially requiring intensive care | |||
* Immunocompromised hosts | |||
* Alcoholism | |||
* Travelled within the past 2 week | |||
* Age > 50 years | |||
* In areas of an outbreak | |||
* Suspected healthcare-associated pneumonia | |||
===Polymerase Chain Reaction=== | |||
Nucleic acid amplification-based methods can be used to identify mip gene of Legionella in sputum, serum, and urine. Sensitivities range from 80–100% for lower respiratory tract secretion, 30–80% for serum, and 0–90% for urine samples.<ref>{{Cite journal| doi = 10.1007/s10096-011-1535-0| issn = 1435-4373| volume = 31| issue = 8| pages = 2017–2028| last1 = Mentasti| first1 = M.| last2 = Fry| first2 = N. K.| last3 = Afshar| first3 = B.| last4 = Palepou-Foxley| first4 = C.| last5 = Naik| first5 = F. C.| last6 = Harrison| first6 = T. G.| title = Application of Legionella pneumophila-specific quantitative real-time PCR combined with direct amplification and sequence-based typing in the diagnosis and epidemiological investigation of Legionnaires' disease| journal = European Journal of Clinical Microbiology & Infectious Diseases: Official Publication of the European Society of Clinical Microbiology| date = 2012-08| pmid = 22278293}}</ref><ref>{{cite book | last = Versalovic | first = James | title = Manual of clinical microbiology | publisher = ASM Press | location = Washington, DC | year = 2011 | isbn = 978-1555814632 }}</ref> | |||
===Serology test=== | |||
A 4-fold or greater rise in antibody titer between acute and convalescent sera may be diagnostic. However, seroconversion is not detectable until at least 3 weeks after infection and does not occur in up to a quarter of patients with culture-proven disease.<ref>{{Cite journal| doi = 10.1016/S0140-6736(15)60078-2| issn = 1474-547X| last1 = Cunha| first1 = Burke A.| last2 = Burillo| first2 = Almudena| last3 = Bouza| first3 = Emilio| title = Legionnaires' disease| journal = Lancet (London, England)| date = 2015-07-28| pmid = 26231463}}</ref> | |||
===Culture=== | |||
Culture of samples (e.g., expectorated sputum, endotracheal aspirates, pleural fluid, blood, or tissue) remains the gold standard for detecting Legionnaires' disease. Unlike serology and urine antigen testing, the yield of cultures is independent of serotype and may be positive in cases of non-''Legionella pneumophila'' species. The culture of non-respiratory samples is warranted when suspecting extrapulmonary infection. Buffered charcoal-yeast extract (BCYE) medium supplemented with 0.1% α-ketoglutaric acid is required for isolation and growth of Legionella.<ref>{{Cite journal| doi = 10.1016/S0140-6736(15)60078-2| issn = 1474-547X| last1 = Cunha| first1 = Burke A.| last2 = Burillo| first2 = Almudena| last3 = Bouza| first3 = Emilio| title = Legionnaires' disease| journal = Lancet (London, England)| date = 2015-07-28| pmid = 26231463}}</ref> | |||
==References== | ==References== | ||
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[[Category:Bacterial diseases]] | [[Category:Bacterial diseases]] | ||
[[Category:Medical disasters]] | [[Category:Medical disasters]] | ||
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Laboratory abnormalities in Legionnaries' disease include leukocytosis with relative lymphopenia, hyponatremia, hypophosphatemia, and elevated levels of AST/ALT, CPK, ESR, CRP, LDH, and ferritin. Urine antigen testing in the first-line diagnostic method. Culture of the lower respiratory secretion is the gold standard for detecting Legionnaires' disease.
Laboratory Findings
Laboratory findings of Legionnaires' disease include:[1]
- Leukocytosis
- Lymphopenia
- Hyponatremia
- Hypophosphatemia
- Elevated AST and ALT
- Elevated CPK
- Elevated ESR and CRP
- Elevated LDH
- Elevated ferritin
Diagnostic Studies
Microscopy
Legionella pneumophila are small, Gram-negative coccabacilli which may be difficult to detect in specimens by Gram staining.[2] The organism can also be detected by immunofluorescent microscopy with the use of direct fluorescent antibody.
Urine Antigen Test
The detection of soluble antigens (a component of the cell wall lipopolysaccharide) in the urine is the first-line diagnostic technique. The method is most accurate for detecting Lp1 MAb 3/1 subtypes. Sensitivity ranges from 56–99% and is lower in nosocomial infection and immunocompromised hosts.[3] Urine antigen test may also be positive for Pontiac fever. IDSA/ATS guidelines recommend urinary antigen test for the following patients:[4]
- Unresponsive to outpatient antibiotic therapy
- Severe pneumonia especially requiring intensive care
- Immunocompromised hosts
- Alcoholism
- Travelled within the past 2 week
- Age > 50 years
- In areas of an outbreak
- Suspected healthcare-associated pneumonia
Polymerase Chain Reaction
Nucleic acid amplification-based methods can be used to identify mip gene of Legionella in sputum, serum, and urine. Sensitivities range from 80–100% for lower respiratory tract secretion, 30–80% for serum, and 0–90% for urine samples.[5][6]
Serology test
A 4-fold or greater rise in antibody titer between acute and convalescent sera may be diagnostic. However, seroconversion is not detectable until at least 3 weeks after infection and does not occur in up to a quarter of patients with culture-proven disease.[7]
Culture
Culture of samples (e.g., expectorated sputum, endotracheal aspirates, pleural fluid, blood, or tissue) remains the gold standard for detecting Legionnaires' disease. Unlike serology and urine antigen testing, the yield of cultures is independent of serotype and may be positive in cases of non-Legionella pneumophila species. The culture of non-respiratory samples is warranted when suspecting extrapulmonary infection. Buffered charcoal-yeast extract (BCYE) medium supplemented with 0.1% α-ketoglutaric acid is required for isolation and growth of Legionella.[8]
References
- ↑ Cunha, Burke A. (2010-03). "Legionnaires' disease: clinical differentiation from typical and other atypical pneumonias". Infectious Disease Clinics of North America. 24 (1): 73–105. doi:10.1016/j.idc.2009.10.014. ISSN 1557-9824. PMID 20171547. Check date values in:
|date=(help) - ↑ Versalovic, James (2011). Manual of clinical microbiology. Washington, DC: ASM Press. ISBN 978-1555814632.
- ↑ Helbig, Jürgen H.; Uldum, Søren A.; Bernander, Sverker; Lück, Paul Christian; Wewalka, Günther; Abraham, Bill; Gaia, Valeria; Harrison, Timothy G. (2003-02). "Clinical utility of urinary antigen detection for diagnosis of community-acquired, travel-associated, and nosocomial legionnaires' disease". Journal of Clinical Microbiology. 41 (2): 838–840. ISSN 0095-1137. PMC 149701. PMID 12574296. Check date values in:
|date=(help) - ↑ Mandell, Lionel A.; Wunderink, Richard G.; Anzueto, Antonio; Bartlett, John G.; Campbell, G. Douglas; Dean, Nathan C.; Dowell, Scott F.; File, Thomas M.; Musher, Daniel M.; Niederman, Michael S.; Torres, Antonio; Whitney, Cynthia G.; Infectious Diseases Society of America; American Thoracic Society (2007-03-01). "Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults". Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America. 44 Suppl 2: –27-72. doi:10.1086/511159. ISSN 1537-6591. PMID 17278083.
- ↑ Mentasti, M.; Fry, N. K.; Afshar, B.; Palepou-Foxley, C.; Naik, F. C.; Harrison, T. G. (2012-08). "Application of Legionella pneumophila-specific quantitative real-time PCR combined with direct amplification and sequence-based typing in the diagnosis and epidemiological investigation of Legionnaires' disease". European Journal of Clinical Microbiology & Infectious Diseases: Official Publication of the European Society of Clinical Microbiology. 31 (8): 2017–2028. doi:10.1007/s10096-011-1535-0. ISSN 1435-4373. PMID 22278293. Check date values in:
|date=(help) - ↑ Versalovic, James (2011). Manual of clinical microbiology. Washington, DC: ASM Press. ISBN 978-1555814632.
- ↑ Cunha, Burke A.; Burillo, Almudena; Bouza, Emilio (2015-07-28). "Legionnaires' disease". Lancet (London, England). doi:10.1016/S0140-6736(15)60078-2. ISSN 1474-547X. PMID 26231463.
- ↑ Cunha, Burke A.; Burillo, Almudena; Bouza, Emilio (2015-07-28). "Legionnaires' disease". Lancet (London, England). doi:10.1016/S0140-6736(15)60078-2. ISSN 1474-547X. PMID 26231463.