CENTRAL DIABETES INSIPIDUS UNMASKED AFTER KIDNEY TRANSPLANT: A CASE REPORT

Patients who undergo pituitary surgery are prone to develop Central Diabetes Insipidus (CDI) post-operatively on top of other expected hormonal deficiencies. CDI is characterized by decrease in release of antidiuretic hormone (ADH) and present clinically with polyuria, nocturia and polydipsia. However in patients with End Stage Renal Disease (ESRD) and on maintenance dialysis, CDI may be masked. To the best of our knowledge, there have only been 4 previous published study with regards unmasking of CDI post-kidney transplantation.

Here we report a case of a 62-year-old male with history of resection of a pit uit ary mac roadenoma and ESRD sec ondary t o Diabet ic Nephropat hy on maintenance dialysis admitted for living non-related kidney transplantation. Pre- transplantation, he was on maintenance desmopressin for CDI but when we developed ESRD, CDI was masked. His kidney transplant went uneventful.

Post-transplantation, he developed polyuria, increasing serum sodium levels, borderline high serum osmolality and low urine osmolality. In lieu of measuring plasma ADH levels, fluid restriction was done which resulted to increase sodium levels. A diagnosis of Diabetes Insipidus was made. He was started on oral desmopressin with noted improvement of symptoms. He was eventually discharged improved. On succeeding outpatient consults, patient’s daily urine output exceeded to 4L/day and his dose of desmopressin was increased to 100mcg twice daily. He remained clinically stable with average daily urine output of 3L/day, normal sodium levels and good renal allograft function.

Successful kidney transplantation leads to unmasking of pre-existing CDI, which when missed may lead to rapid dehydration and hypernatremia. This can be prevented by prompt institution of desmopressin therapy.