Bronchiolitis obliterans organising pneumonia: a clinical and radiological review

The clinical presentation, course, and radiological spectrum of bronchiolitis obliterans organising pneumonia (BOOP) is still being characterised to aid differentiation from other causes of organising pneumonia.

To define the clinical presentation, response to therapy, and radiological spectrum of BOOP.

Fifteen cases of BOOP were retrospectively reviewed. The clinical presenting features, treatment and outcome of each patient were determined. Three independent readers and chest X-rays (CXRs) were blinded. CXRs were scored by a semi-quantitative method. Modal scores were calculated for type and profusion of opacification of each CXR.

The mean age of presentation was 64 years and the median duration of follow-up was 12.5 months. Thirteen patients received corticosteroid therapy. Outcome was varied. One patient had progressive loss of lung function, five had persisting symptoms with stable abnormal lung function, and nine were asymptomatic with near normal lung function. Five patients had a disease relapse. Symptoms length prior to presentation, duration and intensity of treatment were not associated with outcome (p = 0.23-0.9). Radiological opacities were alveolar in 73%, large localised infiltrates in 13%, nodular in 20% and mobile in 33% of CXR series. There was no relationship between overall profusion, type of CXR opacities and patient outcome, treatment duration or treatment intensity (p = 0.42-1.0).

The clinical spectrum of BOOP includes mild subacute, chronic progressive, and acute life threatening illness. Prognosis and response to treatment is variable. The diversity of radiological findings and clinical presentations should prompt consideration of the diagnosis in patients with undiagnosed respiratory tract symptoms and persisting or varying radiological abnormalities.