Tropical pulmonary eosinophilia (TPE) presents as an acute syndrome with dyspnea, fluffy infiltrates, and rounded opacities on the chest radiograph, reduced lung function, marked eosinophilia in the blood and lower respiratory tract, and high titers of specific IgE and IgG antifilarial antibodies. The standard therapy for TPE is a 3-wk course of diethylcarbamazine (DEC) following which there is almost always a marked improvement in all parameters. However, clinical observations suggest that the disease can persist despite DEC therapy and lead to chronic dyspnea with restrictive lung impairment. To evaluate the concept that DEC therapy is not completely 'curative' for TPE, but rather leaves most individuals with a mild, chronic form of TPE defined by persistent inflammation of the lower respiratory tract, we evaluated 23 individuals an average of 12 ± 2 months following a standard 3-wk course of diethylcarbamazine for acute TPE. In the majority there were mild, persistent symptoms referrable to the lung, chest x-ray abnormalities, blood eosinophilia, and elevated serum IgE and filarial specific IgG. On the average, lung function was consistent with the presence of chronic, mild interstitial lung disease. When the inflammatory cells from the lower respiratory tract were examined, there was a persistent eosinophilic alveolitis (TPE/post-DEC 1769 ± 376 eosinophils/μl epithelial lining fluid; normal subjects 256 ± 38, p < 0.02). Evaluation of the lower respiratory tract inflammatory cells recovered from the TPE/post-DEC-treated individuals demonstrated spontaneous release of exaggerated amounts of O-/2̇ and H2O2 compared to normal subjects (p < 0.05, both comparisons). Thus, following a standard 3-wk course of DEC therapy, most patients show improvement but not complete resolution of TPE, and many are left with chronic respiratory tract inflammation and a mild form of interstitial lung disease. Alternative antifilarial drugs or regimens of corticosteroids may be useful in treating this chronic form of TPE.
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine