Summary
Definition
History and exam
Key diagnostic factors
- presence of risk factors
- abrupt onset of high fever
- flu-like illness
- severe headache
- cough
- inspiratory crackles, rhonchi, or wheezing
- hepatomegaly
Other diagnostic factors
- exanthemas
- pleuritic chest pain
- seizures
- coma
- chronic fatigue
- signs of endocarditis or vascular infection (persistent focalised infection)
- other signs of persistent focalised infection
- other signs of acute infection
Risk factors
- exposure to infected animals
- occupational exposure
- travel or residency in endemic areas
- male sex
- age 30 to 70 years
- immunosuppression
- pre-existing cardiac disease
- pre-existing vasculopathy
- pregnancy
Diagnostic investigations
1st investigations to order
- indirect immunofluorescence assay (IFA)
- polymerase chain reaction (PCR)
- FBC
- CRP
- LFTs
- activated partial thromboplastin time (aPTT)
- IgG anticardiolipin (aCL) antibodies
Investigations to consider
- cerebrospinal fluid cell count and differential
- cerebrospinal fluid protein
- cerebrospinal fluid glucose
- CXR
- transthoracic echocardiography (TTE)
- transoesophageal echocardiography (TOE)
- liver ultrasound
- abdominal CT scan or ultrasound
- chest CT
- brain CT
- 18F-fluorodeoxyglucose (FDG) PET/CT imaging
- lymph node biopsy
- immunohistochemistry
- fluorescence in situ hybridisation (FISH)
Treatment algorithm
acute infection, non-pregnant, no severe immunodeficiency: at low risk of persistent focalised infection
acute infection, non-pregnant, no severe immunodeficiency: at high risk of persistent focalised infection
acute infection, non-pregnant, with severe immunodeficiency
acute infection, pregnant
suspected or confirmed persistent focalised infection, with no severe immunodeficiency
suspected or confirmed persistent focalised infection, with severe immunodeficiency
Contributors
Authors
Stephen Gluckman, MD
Professor of Medicine
Medical Director, Penn Global Medicine
Hospital of the University of Pennsylvania
Penn International Medicine and Immunization Clinic; Penn Center for Primary Care
Philadelphia
PA
Disclosures
SG declares that he has no competing interests.
Acknowledgements
Professor Stephen Gluckman would like to gratefully acknowledge Dr Joshua Hartzell, Dr Matthieu Million, Professor Didier Raoult, and Dr Nilmarie Guzman, previous contributors to this topic.
Disclosures
MM and DR are authors of several references cited in this topic. JH and NG declare that they have no competing interests.
Peer reviewers
Jennifer McQuiston, DVM, MS, DACVPM
Epidemiology Team
Rickettsial Zoonoses Branch
National Center for Zoonotic Vectorborne and Enteric Diseases
Centers for Disease Control and Prevention
Atlanta
GA
Disclosures
JM declares that she has no competing interests.
Dimitrios Chatzidimitriou, MD, PhD
Clinical Microbiologist
National Influenza Center
Second Department of Microbiology
Aristotle University of Thessaloniki Medical School
Thessaloniki
Greece
Disclosures
DC declares that he has no competing interests.
Differentials
- Legionella infection
- Tularaemia
- Viral hepatitis
More DifferentialsGuidelines
- A guide to utilization of the microbiology laboratory for diagnosis of infectious diseases
- Health information for international travel: Q fever
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