At a Glance

The milk-alkali syndrome is an acquired condition with hypercalcemia and relative metabolic alkalosis. The disease classically occurs in patients drinking large amounts of milk and/or chronically taking high doses of calcium carbonate (either as antacid or calcium supplement) or sodium bicarbonate. With the shift toward histamine-2 receptor antagonists (e.g., ranitidine) and proton pump inhibitors for treatment of gastroesophageal reflux and peptic ulcer disease, use of antacids has declined.

However, the milk-alkali syndrome has had a recent resurgence in patients (especially post-menopausal women) taking high doses of calcium supplements to prevent osteoporosis. Consumption of milk and vitamin D supplements aggravates the syndrome. Milk-alkali syndrome is usually asymptomatic but may also present with signs and symptoms related to hypercalcemia, such as fatigue, weakness, mental changes, constipation, excessive urination, and renal stones.

What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?

The basic laboratory work-up includes serum calcium, parathyroid hormone (PTH), albumin, phosphorus, creatinine, blood urea nitrogen, thyroid function tests, and 25-hydroxyvitamin D. The combination of hypercalcemia and low PTH in the setting of a compatible history supports the diagnosis.

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Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications – OTC drugs or Herbals – that might affect the lab results?

Low serum albumin can complicate interpretation of serum calcium. In patients with hypoalbuminemia, corrected calcium should be calculated or, alternatively, an ionized calcium measured.

What Lab Results Are Absolutely Confirmatory?

There is no confirmatory test. Diagnosis is made by a combination of history and laboratory studies.

Additional Factors of Clinical Importance

Milk-alkali syndrome is rarely fatal but can lead to long-term complications if not diagnosed and managed properly.

Errors in Test Selection and Interpretation

The diagnosis of hypercalcemia is broad, and other causes of hypercalcemia should be ruled out before diagnosing milk-alkali syndrome. Incomplete laboratory work-up can miss other more common causes of hypercalcemia, such as elevated vitamin D, hyperthyroidism, and hyperparathyroidism.