Bellomo et al listed criteria for the diagnosis of cryptogenic organizing pneumonitis. The authors are from Monash Medical Centre in Melbourne, Australia.
Major criteria:
(1) pulmonary infiltrate on chest X-rays
(2) intraluminal organizing fibrosis of the distal airspaces as the dominant histologic feature, with or without bronchiolitis obliterans
(3) clinical and radiographic response to steroids
(4) exclusion of secondary causes
Secondary causes:
(1) toxic fume inhalation
(2) connective tissue disease
(3) infection with virus, bacteria or fungus
(4) eosinophilic pneumonia
(5) hypersensitivity pneumonitis
Minor criteria:
(1) subacute constitutional illness with dry cough
(2) restrictive pattern by spirometry AND reduced DLco
(3) hypoxemia
(4) inspiratory crackles
(5) elevated erythrocyte sedimentation rate (ESR) and white blood cell count
(6) absence of finger clubbing
(7) non-productive cough
The diagnosis of COP/BOOP requires:
(1) all 4 major criteria
(2) >= 3 minor criteria
where:
• Dry cough (minor 1) and non-productive cough (minor 7) seem to be the same thing.
• The findings are cryptogenic when no secondary cause is found, but many of the findings can be seen if any of the secondary causes are present.
