Normocalcemic hyperparathyroidism associated with relatively low 1:25 vitamin D levels post-renal transplant can be successfully treated with oral calcitriol.
Since endogenous 1:25 vitamin D (1:25VD) is principally involved with involution of secondary hyperparathyroidism post-renal transplant we correlated 1:25VD levels with intact PTH in 82 random patients with a serum creatinine of < 2 mg/dl and with normal hepatic function. All patients studied were normocalcemic with normal phosphorus and received azathioprine, cyclosporin A and prednisone. Of considerable interest, of the 42 patients studied after 2 years post-transplant, there were 8 (19%) patients with intact PTH of more than twice the upper limit of normal (normal 10-65 pg/ml) and other 15 (36%) with PTH levels above normal. Secondly, in no patient did we see 1:25VD above normal (normal 15-60 pg/ml) despite levels of PTH of > 200 pg/ml. Of concern, 20% of 73 patients had 1:25VD deficiency (< 15 pg/ml). This may not have been previously appreciated because of the number of patients studied. Like previous investigators, we failed to understand why 1:25VD levels were relatively low. There was no correlation between 1:25VD and serum creatinine. Of 25 patients with a serum creatinine of 1.4 or less, there were 10 patients (40%) with 1:25VD of less than 20 pg/ml. Since persistently high PTH can contribute to bone demineralization, which is not uncommon post-transplant, we treated 8 patients with small doses of oral 1:25VD (rocaltrol). In less than 6 months PTH levels returned to normal in 7 of the 8 patients. The current studies clearly indicate that asymptomatic hyperparathyroidism is common even after 2 years post-renal transplant. Monitoring for PTH and 1:25VD will help prevent bone disease post-transplant now that rocaltrol is available.
Lobo
P I
PI
Transplant Service Department of Internal Medicine, University of Virginia School of Medicine, Charlottesville, USA.
Cortez
M S
MS
Stevenson
W
W
Pruett
T L
TL
D000293:Adolescent; D000328:Adult; D000368:Aged; D001379:Azathioprine / Q000627:therapeutic use; D002117:Calcitriol / Q000097:blood* / Q000172:deficiency / Q000627:therapeutic use*; D002118:Calcium / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D012080:Chronic Kidney Disease-Mineral and Bone Disorder / Q000517:prevention & control; D003404:Creatinine / Q000097:blood; D016572:Cyclosporine / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood* / Q000188:drug therapy*; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D016030:Kidney Transplantation / Q000009:adverse effects; D008099:Liver / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood; D011241:Prednisone / Q000627:therapeutic use
D005938:Glucocorticoids; D007166:Immunosuppressive Agents; D010281:Parathyroid Hormone; D010758:Phosphorus; D016572:Cyclosporine; D003404:Creatinine; D002117:Calcitriol; D001379:Azathioprine; D002118:Calcium; D011241:Prednisone