Which extrapulmonary findings suggest atypical community-acquired pneumonia (CAP)?

Updated: Oct 31, 2019
  • Author: Stephanie L Baer, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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Atypical community-acquired pneumonia (CAP) has classically been associated with more extrapulmonary manifestations than typical bacterial CAP. However, there can be considerable overlap in the clinical presentation of CAP due to various pathogens such that a definitive microbiologic diagnosis cannot be made based on signs and symptoms alone. Certain constellations of findings in the setting of appropriate historical clues may suggest an increased likelihood of a specific pathogen, thus warranting a targeted investigation for that organism. A detailed review of all potential extrapulmonary findings in CAP is beyond the scope of this article; however, some classic associations are included below:

M pneumoniae CAP is associated with the following findings: [48]

  • Headache, fever, malaise, sore throat in young adult with insidious onset of cough
  • Erythema multiforme major (Stevens-Johnson syndrome)
  • Cardiac conduction abnormalities
  • Hemolytic anemia and cold-agglutinin syndrome
  • Neurologic abnormalities, including aseptic meningitis or meningoencephalitis, Guillain-Barre syndrome, transverse myelitis
  • Epidemic outbreaks, eg, in schools or military barracks

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