[A case of the milk-alkali syndrome with a small amount of milk and magnesium oxide ingestion--the contribution of sustained metabolic alkalosis induced by hypertonic dehydration].

We described a patient with the milk-alkali syndrome induced by the ingestion of small amount of milk (200 ml/day) and ice cream (145 g/day) and the administration of small dose of absorbable alkali (magnesium oxide 2.0 g/day) for the treatment of chronic constipation. The present case shows not only triads, i.e., hypercalcemia (s-Ca 14.3 mg/dl), metabolic alkalosis (s-HCO3- 37.4 mEq/L), and renal insufficiency (s-Cre 2.3 mg/dl) but also hypernatremia (s-Na 161 mEq/L) and hypertonic dehydration after the frequent episodes of elevated body temperature. The milk-alkali syndrome has been defined as the hypercalcemia with a metabolic alkalosis from a high amount of calcium intake and long term administration of absorbable alkali in any form, usually as calcium carbonate for the treatment of peptic ulcer. As the present case could be distinguished from any other cases previously reported with regard to the amount of calcium (0.4 g/day) and alkali (36 mEq/day) intake and the clinical situations that induced the syndrome, we compared the present case with the previous reports, calculating the amount of calcium and alkali intake from milk and absorbable alkali. After the introduction of the H2 blockers for peptic ulceration, the most cases with milk-alkali syndrome had provoked by the smaller amount of calcium than previously reported, which were associated with the treatment of relatively large amount of alkali (50-150 mEq/day), suggesting the role of sustained metabolic alkalosis for the development. In the present case the metabolic alkalosis induced by hypertonic dehydration and enhanced by absorbable alkali intake also could cause an increase of renal tubular reabsorption of calcium and a decrease of ionized calcium which might produce increased secretion of parathyroid hormone followed by vitamin D3 activation and increased Ca absorption from the gut. The metabolic alkalosis might be essential to the development of the milk-alkali syndrome without a high calcium and absorbable alkali intake.