Incomplete Distal Renal Tubular Acidosis in Hypomagnesemia-Dependent Hypocalcemia

Symptomatic hypocalcemia and hypomagnesemia, both responsive to replenishment of magnesium, occur in chronic alcoholism,1malabsorption,2experimentally induced magnesium deficiency,3primary magnesium deficiency,4and severe malnutrition.3,5The cause of hypocalcemia in these conditions is unknown. Postulated mechanisms include decreased secretion or defective synthesis of parathyroid hormone6,7or peripheral resistance to parathyroid hormone.4,8 I will describe two patients with hypocalcemia and hypomagnesemia who also had tetany, incomplete distal renal tubular acidosis, and increased concentrations of serum parathyroid hormone, all of which conditions responded to magnesium replenishment. PATIENT SUMMARIES Patient 1.— In 1954, a female patient developed diarrhea and abdominal pain. She was found to have regional enteritis, and a portion of small bowel was resected. In 1962, another portion of small bowel was resected because of acute intestinal obstruction. Two months later, the patient developed tetany and hypocalcemia and was treated with orally and intravenously