Hyponatremia Reveals Hidden Peritransplant Abscess After Kidney Transplant

A 68-year-old woman who underwent living unrelated kidney transplantation developed severe hyponatremia (sodium 109 mmol/L) on postoperative day 8 with only mild symptoms. Sodium improved with hypertonic saline, nutrition, and fluid restriction. By postoperative day 13 she spiked a fever; CT revealed a large (16 cm) peritransplant abscess, with drainage growing Escherichia coli. This case suggests severe unexplained hyponatremia can be an early manifestation of occult infectious or surgical complications after kidney transplantation.