Learning Radiology xray montage

Mycoplasma Pneumonia
Primary Atypical Pneumonia

  • Commonest cause of nonbacterial pneumonia

  • Mild course; lasts 2-3 weeks

  • Peak in autumn and winter

  • Common (1/3 of all pneumonias) in service personnel

  • Organism: Eaton agent=pleuropneumonia-like organism (PPLO) – probably a bacterium


  • One group has acute onset of fever, cough, chest pain associated with segmental pneumonia

  • Other group has 1-4 week history of lethargy and SOB and is usually associated with interstitial disease

  • May have bullous myringitis

  • Cultures take 3 months so 4X rise in cold agglutinins is used in diagnosis


  • Acute interstitial infiltrate in lower lobes radiating from hila (early)

  • Then alveolar infiltrates, usually unilateral and almost always segmental

  • Usually lower lobes

  • Small pleural effusion in 20%

  • Rare hilar adenopathy


  • Meningitis

  • Encephalitis

  • Stevens-Johnson syndrome (erythema multiforme, high fever, stomatitis and pneumonia)

  • Erythema nodosum