Diffuse panbronchiolitis (DPB) or Asian panbronchiolitis is an idiopathic progressive inflammatory small airway obstructive lung disease.
There is striking predilection in east Asia (e.g. Japan, Korea, China). It tends to present in middle aged (~ 30-60-year-old) adults, often nonsmokers. There is a high prevalence rate in males with a M:F ratio of ~ 2:1.
It is most likely associated with infections such as H. influenza, P. aeruginosa, and type 1 human T-lymphotropic virus in genetically susceptible people.
Diffuse panbronchiolitis is characterised by centrilobular peribronchiolar infiltrates of acute and chronic inflammatory cells, which occur principally at the level of the respiratory bronchioles. There can be bronchiolar dilatation and intra-luminal inflammatory exudates.
Histologically, so called "DPB unit lesion" is comprised of foamy macrophages and lymphoid infiltrates.
Nonspecific and may show bilateral, diffuse, small nodular shadows with pulmonary hyperinflation.
A periphero-basilar predilection may be present. Features are generally non specific and include:
centrilobular opacities with branching lines (tree-in-bud pattern 4)
- basal predominant bronchiolectasis
- mosaic attenuation with expiratory air trapping
Treatment and prognosis
Often treated with long term low dose erythromycin. If untreated can be progressive even leading to death.
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