Severe Hyponatremia as an Early Manifestation of Peritransplant Abscess After Living Donor Kidney Transplantation: A Case Report.

Electrolyte abnormalities are common after kidney transplantation, but severe hyponatremia as an early sign of occult peritransplant infection is rare. A 68-year-old woman underwent living unrelated kidney transplantation and was discharged on postoperative day 4 with a drain in place. On postoperative day 8, she developed acute kidney injury and profound hyponatremia, with a serum sodium level of 109 mmol/L, despite only mild fatigue and no fever, abdominal pain, allograft tenderness, or wound symptoms. Sodium improved with hypertonic saline, nutritional support, and fluid restriction. On postoperative day 13, she developed fever; computed tomography revealed a 16-cm peritransplant abscess, and drainage grew Escherichia coli. This case highlights severe unexplained hyponatremia as a potential early manifestation of occult infectious or surgical complications after kidney transplantation.