The immunosuppressive effect of corticosteroids is well known. In some circumstances prophylactic antibiotic therapy is routinely used to lower the risk of opportunistic infections in immunocompromised patients with exogenous hypercortisolemia. The incidence of opportunistic infection in endogenous hypercortisolemia in Cushings syndrome is 1117%, correlating with degree of hypercotisolemia. Only several case reports have been published about pneumocystis pneumonia in Cushings syndrome. Idea that pnemocystis pneumonia appears after decreasing hypercortisolemia with medical treatment is speculated. Two cases of severe pneumocystis pneumonia infection in severe Cushings syndrome are described. The first, 60 years old woman with hypertension and hypokalemic alkalosis, who presented with plasma cortisol 3150 nmol/l (normal <650), ACTH 250 pg/ml (normal <50) and free urinary cortisol 13 630 nmol/l/24 h (normal <270). Dexamethasone suppression test (0.5 mg, 6 hourly for 48 h) was not completed for bowel perforation (initially no symptoms) incidentally founded during CT of abdomen. But no plasma cortisol suppression was present even at first day of test. Pituitary MR was negative and inferior petrosal sinus sampling excluded pituitary dependent Cushing syndrome. Treatment with etomidate and ketoconazole was started with rapid drop of plasma cortisol (1222 nmol/l), but it was complicated with severe pneumocystis pneumonia and sepsis. Antibiotics were used with good response. As no source of ACTH production has been found the patient was subjected to bilateral epinephrectomy.
The second case was a 20 years old man with severe osteoporosis and respiratory failure with artificial ventilation in recent history. There was no suppression in plasma cortisol after dexamethasone test, central hypogonadism and pituitary adenoma on MRI. Treatment with ketoconazole and etomidate was also started before operation and depression in plasma cortisol was followed by severe pneumocystis pneumonia requiring artificial ventilation at ICU.
Both severe infections appeared soon after treatment inauguration. Trimethoprim/sulfamethoxazole prophylaxis seems to be reasonable during lowering plasma cortisol with steroidogenesis blocking drugs.