OBLITERATIVE BRONCHIOLITIS WITH ATYPICAL FEATURES - CT SCAN AND NECROPSY FINDINGS

We describe the natural history of cryptogenic bronchiolitis obliteran s in a patient followed for 24 yrs with serial pulmonary function test s and radiology.Severe, progressive airway obstruction developed, with overinflation but preservation of KCO. There was progressive hypoxaem ia, which worserned on exertion; hypercapnoea was modest until late in the illness. Neither bronchodilators nor steroids were effective. The chest radiograph remained normal; CT showed irregular areas of low at tentuation peripherally throughout the lungs, with Hounsfield numbers typical of emphysema, but no bullae. Postmortem studies included histo logy and quantitative studies of a corrosion cast of one lung. They sh owed marked airway narrowing at all levels, with pruning of peripheral branches, mucus plugging, and some emphysema. The case illustrates th at cryptogenic bronchiolitis obliterans may be chronic and difficult t o distinguish clinically or by investigation from other forms of chron ic obstructive airways disease, particularly emphysema.