Adrenal function & the pattern of glucocorticoid induced eosinopenia in tropical pulmonary eosinophilia

Plasma cortisol levels were estimated in 16 patients with tropical pulmonary eosinophilia (TPE; group A) by radioimmunoassay using 125I labelled cortisol. The cortisol levels showed diurnal variation, the mean levels were 10.22 +/- 4.5 micrograms/dl for the morning samples and 4.91 +/- 2 micrograms/dl for the night samples respectively and were within normal limits. Another six patients with TPE included in the study (group B) had an initial mean plasma cortisol level of 5.83 +/- 1.33 micrograms/dl. Half an hour after intramuscular administration of 250 micrograms of Synacthen (a synthetic glucocorticoid with corticotrophic activity), the mean cortisol level showed a significant rise up to 14.7 +/- 3.54 micrograms/dl (P < 0.01) thus indicating normal adrenocorticohypophysial functions in TPE. There was no significant alteration of total blood eosinophil counts before and after intramuscular Synacthen. An additional 6 patients with TPE (group C) who were given oral prednisolone 30 mg a day for 5 days which was subsequently tapered off in the next 5 days showed a spectacular mid-treatment fall in blood eosinophil levels with a post-treatment rise. In another 3 patients with TPE (group D) total blood eosinophil counts were estimated 4 h after intramuscular hydrocortisone and a prompt eosinopenic response was observed. This indicated that a dose related response to steroids in TPE is unlikely. The absence of eosinopenic response after Synacthen could have been due to the short (half an hour) interval when the eosinophil counts were repeated.