John Hunter Hospital, Newcastle, New South Wales
Background: Polyuria after renal transplantation especially with prevalent living donation is a common temporary phenomenon. Ongoing severe polyuria in previously anuric dialysis patients compounded by a small bladder capacity creates significant disruption to a recipient’s quality of life with persistent nocturia, urinary frequency and potential graft dysfunction due to hypovolaemia. Patients with long-term refractory polyuria have often required bilateral native nephrectomies but in the paediatric population the use of oral fludrocortisone has demonstrated short-term efficacy for the management of post-transplant tubulopathies.
Case Report: A 49 year old gentleman who received his second cadaveric renal transplant in 2016 on a background of known Alports’ syndrome had an initial urine output of 15.5 litres daily. His post-operative course was complicated by refractory hypertension, T cell-mediated rejection and massive pulmonary embolism. One week post-operatively this gentleman was still producing a daily urine volume of approximately 7.5 litres. He was discharged from hospital with a creatinine of 123 µmol/L in the context of having received supplemental intravenous fluids. Initial outpatient management was attempted oral consumption of fluids to match urine output volumes but this became increasingly difficult for the patient to maintain and ultimately some associated graft dysfunction ensued with a rise in creatinine to 241 µmol/L. Oral fludrocortisone was trialled to prevent inpatient admission for hydration and successfully reduced urine volumes to 3 to 4 litres daily. Unfortunately, persistent arterial hypertension and hypokalaemia ultimately warranted cessation of the drug but the polyuria had resolved by this stage.
Conclusions: Medical management of polyuria with oral fludrocortisone could be considered for selected patients with persistent polyuria post-renal transplantation, however, side effects of hypertension and hypokalaemia need to be closely monitored.