Tropical Eosinophilia — A Correlation of Clinical, Histopathologic and Lung Function Studies

¹ Bombay, India

One hundred ten cases of tropical eosinophilia were studied and followed-up for two to five years. Of these, 30 were subjected to an open lung biopsy. A correlation of clinical features, lung function and histopathology form the basis for this paper.

The natural history of this syndrome showed spontaneous remissions and relapses. Long-standing cases (11 of the 110 studied) progressed to increasingly crippling pulmonary fibrosis and pulmonary insufficiency; clinically, such cases had little or no resemblance to the commonly accepted symptom complex of tropical eosinophilia. Twelve per cent of patients with symptoms varying from three months to two years responded inadequately to diethylcarbamazine. Those resistant to diethylcarbamazine could not always be distinguished histopathologically from those who responded well. The significance of this in relation to the etiology of the syndrome is discussed.

Lung function studies (done in all 110 cases before and after therapy) were well correlated with the clinical features and histopathology. Lung functions showed: 1) "restrictive" lung lesion in most cases; 2) moderate airway obstruction plus a "restrictive" lesion in some; 3) impairment of diffusion in patients with long-standing disease; and 4) absence of significant pulmonary hypertension in the cases catheterized.