Dyffuse panbronchiolitis (DPB), an important pulmonary disease entity, was first reported in 1969 in Japan as an entity distinct from bronchial asthma, chronic bronchitis, chronic pulmonary emphysema, bronchiectasis, and alveolitis. This disease is characterized by chronic inflammation localized predominantly in the region of the respiratory bronchioles with inflammatory cell infiltration; its pathogenesis remains unknown. Although not uncommon in Japan, the disease is rare elsewhere.
There have been recent reports, however, documented of two cases in white North American patients and of the first case in an Italian patient. The chief signs of this disease are chronic cough, pyomucous sputum, shortness of breath, wheezing, and hypoxemia. About three-quarters of these patients have associated chronic parasinusitis. Chest roentgenograms show bilateral fine nodular densities, together with hyperinflation of both lungs. Pulmonary function tests show a mixed ventilatory impairment consisting of slight restrictive and marked obstructive disturbance. The HLA-Bw54, found specifically in Japanese and Chinese people, is found more frequently in DPB cases than in healthy persons. Associated diseases include ulcerative colitis, allergic angitis and granulomatosis, and T cell leukemia review.
Reports of chronic respiratory bronchiolitis in adults are not uncommon. Mecklem et al in 1971 reported seven cases of chronic obstructive pulmonary disease of the small airways and proposed a new definition of “small airway disease” Homma et al reported that DPB patients had no evidence of a specific history of toxic gas inhalation, preceding pulmonary infection, or pathologic findings suggestive of chronic bronchitis, bronchiectasis, emphysema, or bronchial asthma.
Epler et al also suggested that an idiopathic form of bronchiolitis obliterans organizing pneumonia (BOOP) was a distinct clinical entity. The disease in patients with BOOP, however, was described as restrictive and not chronic. These lines of evidence suggest that DPB should be recognized as a disease entity, and should be differentiated from other more frequently observed obstructive pulmonary diseases.