Pulmonary and gastric metastatic calcification due to milk-alkali syndrome: a case report

The incidence of metastatic calcification is influenced by high serum calcium and phosphate concentrations and local physicochemical conditions, such as pH. A high pH accelerates tissue calcification. Patients with milk-alkali syndrome typically present with renal failure, hypercalcemia, and metabolic alkalosis, which are caused by the ingestion of calcium and absorbable alkali. Among patients with impairment of renal function, milk-alkali syndrome is a major cause of hypercalcemia. Long-term use of furosemide will lead to hypokalemia, metabolic alkalosis, and eventually renal failure (i.e., pseudo-Bartter syndrome). Even if the level of calcium ingestion is relatively low, the renal failure caused by long-term furosemide use can readily lead to milk-alkali syndrome. We describe a case of a 45-year-old woman who was admitted with cough and dyspnea and presented with pulmonary and gastric metastatic calcification. She had been taking alfacalcidol and oral alkaline medications such as sodium bicarbonate and calcium carbonate as well as oral furosemide for a long time. The patient was found to have hypercalcemia, chronic renal failure, and metabolic alkalosis, so milk-alkali syndrome was diagnosed. Saline was administered and oral medications were discontinued. Serum creatinine levels subsequently decreased, but pulmonary metastatic calcification was not diminished. In this case, the milk-alkali syndrome that caused the severe metastatic calcification was exacerbated by multiple factors, including oral alkaline medications such as sodium bicarbonate and calcium carbonate. In addition, metabolic alkalosis and renal failure were affected by long-term furosemide use (i.e., pseudo-Bartter syndrome).