Renal Transplantation and Transplant-Related Urology
Core concepts
This domain tests the urological complications of transplantation and the work-up of the recipient and donor.
Pre-transplant: know the significance of HLA matching, crossmatching, and the causes of graft loss. Urological evaluation of the recipient includes bladder function (especially in neurogenic bladder or lower urinary tract reconstruction), and exclusion of active infection or malignancy.
Surgical anatomy: the transplant kidney is placed extraperitoneally in the iliac fossa with a short ureter anastomosed to the bladder. This short, denervated ureter is prone to stenosis and leak. Trap: forgetting that the transplanted kidney is denervated, so rejection and obstruction may present without typical pain.
Complications: vascular (renal artery thrombosis, stenosis), urological (ureteric stenosis, urine leak, lymphocoele, vesicoureteric reflux), and immunological (acute rejection, chronic allograft nephropathy). Know that a rising creatinine after transplantation should prompt imaging for obstruction and vascular causes before assuming rejection.
Immunosuppression: calcineurin inhibitors are nephrotoxic; know the common drug interactions and the infection risks (CMV, BK virus nephropathy). BK viraemia with rising creatinine is an examinable trap for rejection.
Post-transplant malignancy: skin cancer and post-transplant lymphoproliferative disorder.
Worked rule of thumb
A transplant recipient with a rising creatinine and a dilated graft collecting system: obstruction, not rejection - the trap answer is to increase immunosuppression, which would be wrong and harmful.
Exam traps
- Attributing all graft dysfunction to rejection.
- Forgetting that the graft is denervated.
- Missing BK virus nephropathy.
- Overlooking bladder dysfunction in the recipient work-up.