5th April 2024

Hypomagnesemia

This is defined as serum magnesium concentrations < 0.7 mmol/L and may be caused by malabsorption syndromes, including Coeliac and inflammatory bowel disease, chronic diarrhoea, short bowel syndrome and prolonged nasogastric suctioning. Other causes include:

• Protein calorie malnutrition – anorexia nervosa
• Parathyroid gland disorders – low magnesium suppresses PTH release and blunts the end organ response to PTH. The resulting hypocalcaemia is refractory to replacement until magnesium is replete. 
• Chronic alcohol excess
• Diabetes where poor glycaemic control results in glucose-induced diuresis
• Medications – proton pump inhibitors, diuretics, digoxin, calcineurin inhibitors, theophylline, cisplatin and some aminoglycosides
• Renal disorders resulting in reduced resorption – renal tubular acidosis, post obstructive diuresis, acute tubular necrosis
• Refeeding syndrome 
• Severe burns
• Acute pancreatitis