Postrenal Transplant Disseminated Cryptococcosis Presenting as a Syndrome of Inappropriate Antidiuretic Hormone Secretion - A Case

Cryptococcosis is the most common invasive fungal infection to involve the central nervous system in the posttransplant period. Cryptococcal meningitis, which constitutes disseminated cryptococcosis, can present with nonspecific signs and symptoms leading to a diagnostic challenge. There are case reports of cryptococcal meningitis presenting as a syndrome of inappropriate antidiuretic hormone secretion (SIADH). A 54-year-old male with autosomal dominant polycystic kidney disease was a live-related renal allograft recipient 1 year back and presented with complaints of generalized weakness and imbalance while walking. His serum sodium on admission was 117 mEq/L and investigations were suggestive of SIADH. He was given hypertonic saline and fluid restriction. However, he had a recurrence of symptomatic hyponatremia. He was evaluated for the cause of SIADH. Chest X-ray and computed tomography of the thorax revealed patchy consolidation. In view of persistent giddiness and imbalance, lumbar puncture was done and cerebrospinal fluid (CSF) analysis showed hypoglycorrhachia with elevated protein and cell counts. CSF cryptococcal antigen test was positive. He was thus diagnosed with disseminated cryptococcosis with meningitis and pulmonary involvement. He received amphotericin B deoxycholate for 4 weeks, followed by fluconazole. He improved symptomatically and serum sodium normalized thereafter. This is the first case of disseminated cryptococcosis presenting with SIADH in the postrenal transplant period with one prior case being reported after a liver transplant. This highlights the variable presentations of cryptococcosis and the need to evaluate the primary cause in posttransplant patients presenting with hyponatremia.