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Legionnaires Disease Clinical Presentation

  • Author: Burke A Cunha, MD; Chief Editor: Michael Stuart Bronze, MD  more...
 
Updated: Mar 30, 2016
 

History

Legionella pneumophila causes 2 distinct disease entities. Legionnaires disease (LD) is characterized by pneumonia. Pontiac fever is a short-term, milder illness than LD and is not characterized by pneumonia, instead manifesting as fever and myalgias that resolve without treatment.

The incubation period in LD ranges from 2-10 days. Patients who develop legionellae infection and who have been hospitalized continuously for 10 or more days before the onset of illness are classified as having definite nosocomial LD. Patients with laboratory-confirmed infection that develops 2-9 days after hospitalization are classified as having possible nosocomial LD. Nosocomial LD occurs in clusters.

Symptoms of LD can occur as follows:

  • Patients often experience a prodrome of 1-2 days of mild headache and myalgias, followed by high fever, and chills
  • Cough is present in 90% of cases; cough usually is nonproductive at first but may become productive as the disease progresses
  • Other pulmonary manifestations include dyspnea, pleuritic chest pain, and hemoptysis, which may be present in as many as one third of cases
  • Gastrointestinal symptoms include nausea, vomiting, diarrhea (watery, not bloody), abdominal pain, and anorexia
  • Neurologic symptoms include headache, lethargy, encephalopathy, altered mental status (the most common neurologic symptom), and rarely, focal symptoms
  • Musculoskeletal symptoms include myalgias
  • Nonpulmonary symptoms are prominent early in the disease
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Physical Examination

Manifestations of LD may include the following:

  • Headache
  • Mental status changes
  • Fever greater than 40°C, or 102°F (range, 38.8-40.5°C)
  • Relative bradycardia (excluding patients with pacemakers or arrhythmias or those receiving beta blockers, diltiazem, or verapamil)
  • Myocarditis
  • Prosthetic valve endocarditis
  • Tachypnea
  • Localized rales
  • Blood-streaked sputum
  • Extrapulmonary manifestations
  • Abdominal pain
  • Pancreatitis
  • Acute renal failure

A clinical point score, as shown in the table below, may be helpful in increasing the probability of correctly diagnosing LD and prompting specific/definitive LD testing.

Table 1. Legionnaires Disease: Six Clinical Predictors and Diagnostic Eliminators in Adults Admitted with Pneumonia a (Open Table in a new window)

Diagnostic PredictorsDiagnostic Eliminators
Clinical Predictors
  • Fever (>102°F)
Clinical Eliminators
  • Sore throat
  • Severe myalgias
Laboratory Predictors b
  • Highly elevated ESR (>90 mm/h) or CRP (>180 mg/L)
  • Highly elevated ferritin levels (>2 X normal)
  • Hypophosphatemia (on admission/early)
  • Highly elevated CPK (>2 X normal)
  • Microscopic hematuria (on admission)
Laboratory Eliminators
  • Leukopenia
  • Thrombocytopenia
  • Negative chest radiographic findings (no infiltrates)
Legionnaire disease very likely if >3 predictors presentLegionnaires disease very unlikely if <3 predictors or >3 diagnostic eliminators present
Abbreviations: CPK = creatinine phosphokinase test; CRP = C-reactive protein; ESR = erythrosedimentation rate.



a Pulmonary symptoms: shortness of breath, cough, and so forth with fever and a new focal/segmental infiltrate on chest radiograph.



b Otherwise unexplained. If finding is due to an existing disorder, it should not be used as a clinical predictor.



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Contributor Information and Disclosures
Author

Burke A Cunha, MD Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital

Burke A Cunha, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Michael Stuart Bronze, MD David Ross Boyd Professor and Chairman, Department of Medicine, Stewart G Wolf Endowed Chair in Internal Medicine, Department of Medicine, University of Oklahoma Health Science Center; Master of the American College of Physicians; Fellow, Infectious Diseases Society of America

Michael Stuart Bronze, MD is a member of the following medical societies: Alpha Omega Alpha, American Medical Association, Oklahoma State Medical Association, Southern Society for Clinical Investigation, Association of Professors of Medicine, American College of Physicians, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Additional Contributors

Frank C Smeeks, III, MD Specialty Medical Director of Emergency Medicine, Applied Medico Legal Solutions

Frank C Smeeks, III, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Association for Physician Leadership, American Medical Association, North Carolina Medical Society

Disclosure: Nothing to disclose.

Acknowledgements

Joseph F John Jr, MD, FACP, FIDSA, FSHEA Clinical Professor of Medicine, Molecular Genetics and Microbiology, Medical University of South Carolina College of Medicine; Associate Chief of Staff for Education, Ralph H Johnson Veterans Affairs Medical Center

Disclosure: Nothing to disclose.

Eric M Kardon, MD, FACEP Attending Emergency Physician, Georgia Emergency Medicine Specialists; Physician, Division of Emergency Medicine, Athens Regional Medical Center

Eric M Kardon, MD, FACEP is a member of the following medical societies: American College of Emergency Physicians

Disclosure: Nothing to disclose.

Fred A Lopez, MD Associate Professor and Vice Chair, Department of Medicine, Assistant Dean for Student Affairs, Louisiana State University School of Medicine

Fred A Lopez, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians-American Society of Internal Medicine, Infectious Diseases Society of America, and Louisiana State Medical Society

Disclosure: Nothing to disclose.

Scott Savage, DO Associate Clinical Faculty, Department of Emergency Medicine, Wright State University, Boonshoft School of Medicine

Disclosure: Nothing to disclose.

Lynn E Sullivan, MD Assistant Professor of Medicine, Yale University School of Medicine

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

Jeter (Jay) Pritchard Taylor III, MD Compliance Officer, Attending Physician, Emergency Medicine Residency, Department of Emergency Medicine, Palmetto Health Richland, University of South Carolina School of Medicine; Medical Director, Department of Emergency Medicine, Palmetto Health Baptist

Jeter (Jay) Pritchard Taylor III, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

References
  1. Kozak-Muiznieks NA, Lucas CE, Brown E, Pondo T, Taylor TH Jr, Frace M, et al. Prevalence of sequence types among clinical and environmental isolates of Legionella pneumophila serogroup 1 in the United States from 1982 to 2012. J Clin Microbiol. 2014 Jan. 52(1):201-11. [Medline]. [Full Text].

  2. Nguyen TM, Ilef D, Jarraud S, Rouil L, Campese C, Che D. A community-wide outbreak of legionnaires disease linked to industrial cooling towers--how far can contaminated aerosols spread?. J Infect Dis. 2006 Jan 1. 193(1):102-11. [Medline].

  3. Woo AH, Goetz A, Yu VL. Transmission of Legionella by respiratory equipment and aerosol generating devices. Chest. 1992 Nov. 102(5):1586-90. [Medline].

  4. Brandsema PS, Euser SM, Karagiannis I, DEN Boer JW, VAN DER Hoek W. Summer increase of Legionnaires' disease 2010 in The Netherlands associated with weather conditions and implications for source finding. Epidemiol Infect. 2014 Jan 24. 1-12. [Medline].

  5. Halsby KD, Joseph CA, Lee JV, Wilkinson P. The relationship between meteorological variables and sporadic cases of Legionnaires' disease in residents of England and Wales. Epidemiol Infect. 2014 Jan 9. 1-8. [Medline].

  6. Cristino S, Legnani PP, Leoni E. Plan for the control of Legionella infections in long-term care facilities: Role of environmental monitoring. Int J Hyg Environ Health. 2011 Sep 16. [Medline].

  7. Lin YE, Stout JE, Yu VL. Controlling Legionella in hospital drinking water: an evidence-based review of disinfection methods. Infect Control Hosp Epidemiol. 2011 Feb. 32(2):166-73. [Medline].

  8. van Loenhout JA, van Tiel HH, van den Heuvel J, Vercoulen JH, Bor H, van der Velden K, et al. Serious long-term health consequences of Q-fever and Legionnaires' disease. J Infect. 2014 Jan 25. [Medline].

  9. Cunha BA. Hypophosphatemia: diagnostic significance in Legionnaires' disease. Am J Med. 2006 Jul. 119(7):e5-6. [Medline].

  10. Kashuba AD, Ballow CH. Legionella urinary antigen testing: potential impact on diagnosis and antibiotic therapy. Diagn Microbiol Infect Dis. 1996 Mar. 24(3):129-39. [Medline].

  11. Tan MJ, Tan JS, Hamor RH, File TM Jr, Breiman RF. The radiologic manifestations of Legionnaire's disease. The Ohio Community-Based Pneumonia Incidence Study Group. Chest. 2000 Feb. 117(2):398-403. [Medline].

  12. Mandell LA, Wunderink RG, Anzueto A, Bartlett JG, Campbell GD, Dean NC, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007 Mar 1. 44 Suppl 2:S27-72. [Medline].

  13. Cunha BA. Legionnaires' disease: clinical differentiation from typical and other atypical pneumonias. Infect Dis Clin North Am. 2010 Mar. 24 (1):73-105. [Medline].

  14. Cunha BA, Strollo S, Schoch P. Extremely elevated erythrocyte sedimentation rates (ESRs) in Legionnaires' disease. Eur J Clin Microbiol Infect Dis. 2010 Dec. 29 (12):1567-9. [Medline].

  15. Cunha BA. Highly elevated serum ferritin levels as a diagnostic marker for Legionella pneumonia. Clin Infect Dis. 2008 Jun 1. 46 (11):1789-91. [Medline].

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This electron micrograph depicts an amoeba, Hartmannella vermiformis (orange), as it entraps a Legionella pneumophila bacterium (green) with an extended pseudopod. After it is ingested, the bacterium can survive as a symbiont within what then becomes its protozoan host. The amoeba then becomes a so-called "Trojan horse," since, by harboring the pathogenic bacterium, the amoeba can afford it protection. In fact, in times of adverse environmental conditions, the amoeba can metamorphose into a cystic stage, enabling it, and its symbiotic resident, to withstand the environmental stress. Image courtesy of the Centers for Disease Control and Prevention and Dr. Barry S Fields.
Table 1. Legionnaires Disease: Six Clinical Predictors and Diagnostic Eliminators in Adults Admitted with Pneumonia a
Diagnostic PredictorsDiagnostic Eliminators
Clinical Predictors
  • Fever (>102°F)
Clinical Eliminators
  • Sore throat
  • Severe myalgias
Laboratory Predictors b
  • Highly elevated ESR (>90 mm/h) or CRP (>180 mg/L)
  • Highly elevated ferritin levels (>2 X normal)
  • Hypophosphatemia (on admission/early)
  • Highly elevated CPK (>2 X normal)
  • Microscopic hematuria (on admission)
Laboratory Eliminators
  • Leukopenia
  • Thrombocytopenia
  • Negative chest radiographic findings (no infiltrates)
Legionnaire disease very likely if >3 predictors presentLegionnaires disease very unlikely if <3 predictors or >3 diagnostic eliminators present
Abbreviations: CPK = creatinine phosphokinase test; CRP = C-reactive protein; ESR = erythrosedimentation rate.



a Pulmonary symptoms: shortness of breath, cough, and so forth with fever and a new focal/segmental infiltrate on chest radiograph.



b Otherwise unexplained. If finding is due to an existing disorder, it should not be used as a clinical predictor.



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