Syndrome of Inappropriate Antidiuretic Hormone Secretion Complicating Systemic Nocardiosis in a Renal Transplant Recipient: A Case Report.

Background: Infection by Nocardia species is an uncommon cause of severe clinical syndromes, particularly in immunocompromised patients, and solid-organ transplantation is the most common underlying condition. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) has been described thus far in lung and stem cell transplants with systemic nocardiosis.

Methods: We report the first case of SIADH in a female elderly renal transplant recipient diagnosed with systemic nocardiosis 2 years after transplantation. The SIADH was managed appropriately, and her immunosuppressive regimen remained unchanged but was adjusted at a lower level. The systemic Nocardia infection was successfully treated with intravenous administration of trimethoprim-sulfamethoxazole and imipenem for 2 weeks followed by oral trimethoprim-sulfamethoxazole for a total of 12 months.

Conclusions: The SIADH syndrome is a recognizable complication of Nocardia infection in renal transplant recipients. Prompt identification along with proper management and prolonged antimicrobial treatment are essential to improve patients' outcome.