162
- An 8-year-old child was diagnosed to have chronic kidney disease (stage 3).
His calcium profile was normal, 25 (OH)D 5 ng/ml and iPTH 600 pg/ml.
Whether to treat this patient with calcitriol or cholecalciferol?
Patients with chronic kidney disease beyond stage three have impaired
1 α-hydroxylase activity; hence, calcium profile, 25(OH)D, and iPTH should be
monitored in these individuals. It is recommended that calcitriol therapy should
be initiated in these patients if iPTH is elevated more than CKD stage-specific
cutoffs despite 25 (OH)D >30 ng/ml or there is hypocalcemia. Hence, therapy
in the index patient should be cholecalciferol and not calcitriol. After adequate
supplementation with cholecalciferol and normalization of 25 (OH)D, serum
iPTH should be reassessed. If iPTH is still elevated above CKD stage specific
cutoffs, additional therapy with calcitriol is indicated. The CKD stage-specific
cutoffs for iPTH are summarized in the table given below.
Stage of CKD Target iPTH (pg/ml)
Stage 3 (eGFR 30–59 ml/min) 35–70
Stage 4 (eGFR 15–29 ml/min) 70–110
Stage 5 (eGFR <15 ml/min) 150–300- A patient with chronic kidney disease on maintenance hemodialysis was found
to be vitamin D deficient [ 25 (OH)D 10 ng/ml]. He was already receiving cal-
citriol therapy. Does this patient require calciferol supplementation?
The index patient with stage 5 CKD is on therapy with calcitriol, the active form
of vitamin D. He also has concurrent vitamin D deficiency. Despite calcitriol
therapy, the index patient should be treated with calciferol and 25(OH)D levels
should be normalized. Supplementation with calciferol normalizes 25(OH)D
levels and provides a substrate for extrarenal 1α-hydroxylase enzyme, thereby
reducing the requirement of calcitriol. Further, 25(OH)D is not only a precursor
for 1,25(OH) 2 D but also has effects independent of 1,25(OH) 2 D, which include
suppression of PTH and improvement in skeletal muscle function. In addition,
it has been shown that normalization of 25(OH)D levels in patients with CKD
on maintenance hemodialysis, who were on calcitriol therapy, results in
improvement in hemoglobin, reduction in doses of erythropoietin and sevelamer,
and has beneficial effects on left ventricular muscle index. - How to treat vitamin D-dependent rickets type 1 and 2?
Children with VDDR type 1 and 2 present in infancy with classical features of
rickets including growth retardation, bony deformities, dental abnormalities,
delayed milestones, and hypocalcemic seizures. Presence of alopecia and high
levels of 1,25(OH) 2 D suggest VDDR type 2. Calcitriol is the treatment of
choice for VDDR type 1, and the recommended dose is 1–3 μg/day in divided
doses, with good therapeutic response. The therapy in patients with VDDR type5 Rickets–Osteomalacia