Tropical eosinophilic lung

All filaria, but most commonly Brugia malayi, may cause radiological changes in the lungs. Clinically, there is almost always a high peripheral eosinophilia, often a dry cough and shortness of breath. Chest radiographs will show multiple small nodules throughout both lungs, indistinct in outline and seldom more than 5 mm in size (Fig. 41). Sometimes there are diffuse homogeneous patches of increased density, which are very difficult to define. These pulmonary abnormalities change frequently, even in a few days, and this is a useful diagnostic finding. The localised densities change in shape and in position and disappear with appropriate treatment. The problem is the differential diagnosis: schistosomiasis, ascariasis, paragonimiasis, and even strongyloidiasis will have to be excluded. Miliary tuberculosis may be a very similar picture, but there is seldom the rapid change in appearance. Most cases of tuberculosis will show hilar lymphadenopathy, and there is not likely to be peripheral eosinophilia.

In a few cases, pulmonary filariasis may leave coarse, localised residual interstitial fibrosis.

Philip E.S. Palmer, with Stanley P. Bohrer, Carlos Bruguera, Xing-Rong Chen, Mahmoud R. EImeligi, Hassen A. Gharbi, S.B. Lagundoye, M. W. Wachira