Atypical pneumonia

Background

• Atypical bugs: chlamydia pneumoniae, legionella pneumophila, mycoplasma pneumoniae

Clinical Features

• Atypical presentation: more likely to have extra-pulmonary symptoms, i.e. arthralgias, fever, malaise, headache

Differential Diagnosis

Causes of Pneumonia

Bacteria

• Gram-positive
  • Streptococcus pneumoniae
  • Staphylococcus aureus
• Gram-negative
  • Haemophilus influenzae
  • Klebsiella pneumoniae
  • Escherichia coli
  • Pseudomonas aeruginosa
  • Moraxella catarrhalis
• Atypical pneumonia
  • Chlamydophila pneumoniae
  • Chlamydophila psittaci
  • Mycoplasma pneumoniae
  • Coxiella burnetti
  • Legionella pneumophila

Viral

• Common
  • Influenza
  • Respiratory syncytial virus
  • Parainfluenza
• Rarer
  • Adenovirus
  • Metapneumovirus
  • Severe acute respiratory syndrome (SARS)
  • Middle east respiratory syndrome coronavirus (MERS)
  • 2019-nCoV (COVID-19)
• Cause other diseases, but sometimes cause pneumonia
  • Herpes simplex virus
  • Varicella-zoster (VZV)
  • Measles
  • Rubella
  • Cytomegalovirus
  • Smallpox
  • Dengue

Fungal

• Histoplasmosis
• Coccidioidomycosis
• Blastomycosis
• Pneumocystis jirovecii pneumonia (PCP)
• Sporotrichosis
• Cryptococcosis
• Aspergillosis
• Candidiasis

Parasitic

• Ascariasis
• Schistosomiasis
• Toxoplasma gondii

Management

• Macrolide antibiotic, e.g. azithromycin

See Also

• Pneumonia