An 8-Year-Old Boy with a History of Congenital Renal Dysplasia

An 8-year-old boy with a history of congenital renal dysplasia is admitted to the hospital for fatigue, nausea, and anorexia over the past few days.  He has been monitored since birth for renal dysfunction, which has worsened over the past few years.  His glomerular filtration rate is 30 mL/min, creatinine is 5.0 mg/dL, and blood urea nitrogen is 100 mg/dL.  On the second hospital day, the patient's glomerular filtration rate falls to 15 mL/min and he requires emergency dialysis.  The attending physician recommends renal allograft transplantation.  After consultation with the nephrologist, the mother says that they would prefer a living donor due to superior outcomes; an older son from her previous marriage has been identified as a match.  The patient's half-brother comes to the hospital for a pre-transplant evaluation.  He is an 18-year-old high school senior with a history of bipolar disorder treated with lithium in the past, and prior cocaine abuse with 2 years of sustained sobriety following residential substance abuse treatment.  He takes no medications.  The half-brother appears uninterested in the interview and frequently glances at his watch, but he perks up when discussing a new sports car that his mother has promised him following his donation procedure.  He has had a difficult time in school but will be graduating on time and going to college.  Which of the following represents a potential contraindication to the half-brother donating his kidney?

A) Donor's age
B) History of bipolar disorder
C) History of cocaine abuse
D) History of lithium treatment
E) Mother's promise to buy him a car