MARKEDLY ELEVATED SERUM LACTATE-DEHYDROGENASE LEVELS ARE A CLUE TO THE DIAGNOSIS OF DISSEMINATED HISTOPLASMOSIS IN PATIENTS WITH AIDS

Disseminated histoplasmosis is a common late manifestation of AIDS, bu t the diagnosis may be unsuspected in some patients because the clinic al presentation of histoplasmosis may mimic other opportunistic infect ions. High serum lactate dehydrogenase (LDH) levels have been associat ed with disseminated histoplasmosis. We therefore evaluated whether ma rkedly increased LDH levels were useful for making a diagnosis of diss eminated histoplasmosis by comparing admission LDH levels for 15 patie nts with culture-proven disseminated histoplasmosis with those for 30 patients dth advanced AIDS who were admitted to the hospital for evalu ation of pulmonary infiltrates and fever. The mean admission LDH level in patients with disseminated histoplasmosis was 1,356 IU/L (range, 1 45-5,410 IU) whereas it was 332 (range, 77-832 IU) in the patients wit h other pulmonary processes. Admission LDH levels were >600 IU in 11 ( 73%) of the 15 patients with disseminated histoplasmosis vs, 3 (10%) o f controls (P <.001). We conclude that markedly elevated admission LDH levels may be a clinical clue to the diagnosis of disseminated histop lasmosis in patients with AIDS.