[Vitamin A poisoning revealed by hypercalcemia in a child with kidney failure]

Patients with chronic renal failure are at risk of vitamin A intoxication, a risk that must be evoked when unexplained hypercalcemia occurs.

An 8 year-old boy with Alagille syndrome and chronic renal failure was admitted because of general deterioration, and bone pain. Severe hypercalcemia (3.9 mmol/L) was present. Serum phosphate, parathyroid hormone and 25 OH D3 levels were normal; 1-25 (OH)2 D3 levels were undetectable. Hypercalcemia was attributed to vitamin A intoxication, due to the administration of a mean daily dose of 12000 IU of vitamin A for at least 2 years. The diagnosis was confirmed by high plasma levels of retinol (1475 micrograms/L). Hypercalcemia only partially responded to treatment with bisphosphonates, calcitonin and dialysis with low calcium dialysate. Serum vitamin A levels remained elevated one month after vitamin A withdrawal. The boy died two months after admission from atrioventricular block.

Vitamin A administration induces a high risk of intoxication in patients with chronic renal failure. Serum vitamin A concentrations are elevated in these patients, because of decreased renal metabolism of retinol, and vitamin A supplements must be avoided.