Idiopathic severe elevation of serum alkaline phosphatase following adult renal transplantation: case reports.

Transient hyperphosphatasemia (TH) in infancy is a benign condition characterized by elevated alkaline phosphatase (ALP) levels severalfold the adult upper limits, occurring mainly in children under 5 years, without evidence of liver or bone disease, and a return to normal ALP levels by 4 months. Herein we have reported 3 cases of TH in adults following renal transplantation. The first case, a 47-year-old woman, blood group AB positive, had hypertensive renal disease. Five months after successful renal transplantation from a deceased donor she had a 50-fold increase in ALP. The second case, a 34-year-old man, blood group A positive, had renal failure due to IgA nephropathy. Nine weeks after a second renal transplant from a deceased donor a 25-fold increase in ALP was noted. The third case, a 45-year-old woman, blood group A positive, experienced renal failure 15 years earlier of unknown etiology. Thirteen years after her second renal transplant a 12-fold increase in ALP was observed during a routine follow-up. In all cases, the isolated ALP serum levels returned to normal limits within 12 weeks. Bone scans and abdominal ultrasounds during these periods were normal with no evidence of bone or liver disease. ALP isoenzyme electrophoresis revealed a pattern characteristic of TH of infancy and childhood. The 3 cases reported highlight the occurrence of benign TH in adults, with renal transplantation. However, liver disease, bone disease, and infection should be excluded first in these susceptible individuals on immunosuppression before establishing the diagnosis of TH.