Milk Alkali Syndrome

Milk alkali syndrome is the triad of hypercalcaemia, metabolic alkalosis and renal impairment from excessive calcium and absorbable alkali intake.

• Resurgent with calcium carbonate use for osteoporosis, antacids, pregnancy heartburn (tums).
• Mechanisms: calcium load, alkalosis (increases tubular calcium reabsorption), volume depletion, vomiting, thiazides, ACE inhibitors and NSAIDs aggravate.
• Third commonest cause of hypercalcaemia in hospitalised patients.

• Nausea, vomiting, abdominal pain, polyuria, confusion, weakness, constipation.
• Hypercalcaemia complications: arrhythmia, short QT, nephrocalcinosis, pancreatitis.
• History of heavy calcium carbonate intake (often over 4 to 5 g elemental calcium daily).

• Hypercalcaemia with suppressed PTH (below 20 pg/mL), metabolic alkalosis, elevated creatinine, hypophosphataemia or normal, low or normal 1,25 vitamin D.
• Review of calcium, antacid, vitamin D and bicarbonate intake.
• Exclude hyperparathyroidism, malignancy (PTHrP), vitamin D toxicity, sarcoidosis, thiazide effect.
• Renal ultrasound for nephrocalcinosis.

• Stop calcium carbonate, vitamin D and alkali sources; stop thiazides, ACE inhibitors, NSAIDs.
• IV isotonic saline 200 to 300 mL/h (aim urine 100 to 150 mL/h) with loop diuretic only after volume repletion (furosemide 20 to 40 mg).
• Severe hypercalcaemia (over 14 mg/dL): add calcitonin 4 to 8 units/kg every 6 to 12 hours, bisphosphonates generally avoided in renal failure, dialysis for refractory cases.
• Treat alkalosis with saline and potassium replacement.
• Renal function usually recovers in days to weeks; some residual impairment.
• Use alternative therapy for osteoporosis; limit calcium intake to 1000 to 1200 mg total daily (diet plus supplements).
• Follow calcium, creatinine and bicarbonate weekly until normal.