Atypical pneumonia (non-COVID-19)

Last reviewed: 21 Apr 2022
Last updated: 03 Nov 2021

Summary

Definition

History and exam

Key diagnostic factors

  • age <50 years
  • persistent cough
  • dry cough
  • long duration of symptoms
More key diagnostic factors

Other diagnostic factors

  • recent community exposure
  • throat involvement
  • fever
  • headache
  • diarrhea
  • bullous myringitis
  • lung rales/crepitations
  • rash
Other diagnostic factors

Risk factors

  • close community settings
  • immunosuppression
  • cigarette smoking
  • chronic lung disease
  • travel
  • male sex
  • immunomodulating drugs
More risk factors

Diagnostic investigations

1st investigations to order

  • chest x-ray
  • WBC count
  • hemoglobin
  • LFTs
  • oxygen saturation in air
  • BUN level
  • real-time reverse transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2
More 1st investigations to order

Investigations to consider

  • urinary Legionella antigen
  • sputum culture for Legionella
  • molecular diagnosis of Mycoplasma pneumoniae or Chlamydophila pneumoniae
  • serology for atypical pathogens
  • nasopharyngeal viral cultures
More investigations to consider

Treatment algorithm

ACUTE

presumed atypical bacterial pneumonia: nonpregnant adult

presumed atypical bacterial pneumonia: pregnant or child

Contributors

Authors

Ran Nir-Paz, MD
Ran Nir-Paz

Associate Professor in Medicine

Department of Clinical Microbiology and Infectious Diseases

Hadassah Hebrew University Medical Center

Jerusalem

Israel

Disclosures

RNP declares that they have no competing interests.

Peer reviewers

Mark Woodhead, BSc, DM, FRCP

Honorary Senior Lecturer (University of Manchester)

Consultant in General & Respiratory Medicine

Department of Respiratory Medicine

Manchester Royal Infirmary

Manchester

UK

Disclosures

MW is an author of a reference cited in this topic.

Ethan Rubinstein, MD

H.E. Sellers Research Chair in Infectious Diseases

Head

Section of Adult Infectious Diseases

Department of Internal Medicine

Department of Medical Microbiology

University of Manitoba

Winnipeg

Canada

Disclosures

At the time of the peer review, Professor Rubinstein declared no competing interests. We were made aware that Professor Rubinstein is now deceased.

  • Differentials

    • Coronavirus disease 2019 (COVID-19)
    • Typical bacterial pneumonia
    • Viral pneumonia
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  • Guidelines

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    • The management of community-acquired pneumonia in infants and children older than 3 months of age
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    Community-acquired pneumonia severity index (PSI) for adults

    CURB-65 pneumonia severity score

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