Histoplasmosis: An Unusual Cause of Adrenal Insufficiency

Adrenal insufficiency (AI), if not diagnosed in a timely manner, can lead to fatal outcomes. Here we describe an unusual case of AI secondary to disseminated histoplasmosis (DH) and the importance of being aware of the association of infections and AI.

A 56-year-old Hispanic man with untreated HIV infection presented for the evaluation of left upper jaw swelling and pain. A brain magnetic resonance imaging scan revealed a 4-cm soft-tissue mass in the left maxilla. Biopsy of the mass was consistent with histoplasmosis. He was also noted to have hyponatremia and hyperkalemia, which raised the suspicion of AI. Laboratory investigation showed a baseline cortisol level of 7 μg/dL (normal, 7-23 μg/dL) and adrenocorticotropic hormone level of 86 pg/mL (normal, 7-69 pg/mL). His 60-minute cortisol level after a 250-μg cosyntropin stimulation test was 9 μg/dL (normal, 7-23 μg/dL). Computed tomography of the chest incidentally noted bilateral adrenal enlargement. An adrenal biopsy was not pursued due to the high index of clinical suspicion of DH as the etiology of AI.

He was diagnosed with adrenal histoplasmosis because of the evidence of AI and bilateral adrenal enlargement in the setting of DH. He was started on glucocorticoid replacement for primary AI and continues to be on glucocorticoids even after 5 years of diagnosis. DH frequently involves the adrenal gland (80%) and can present as adrenal enlargement but does not always cause primary AI.

Our case demonstrates the importance of being vigilant about infections like histoplasmosis as a potential cause of AI. Delay in treatment in such cases could result in life-threatening consequences.