From the Guidelines
Hypomagnesemia is primarily caused by inadequate dietary intake, increased gastrointestinal losses, or excessive renal excretion of magnesium, with common causes including malnutrition, alcoholism, chronic diarrhea, malabsorption syndromes, and certain medications, as well as endocrine disorders and genetic conditions, as reported in the most recent study 1. The causes of hypomagnesemia can be categorized into several key areas, including:
- Dietary causes, such as malnutrition, alcoholism, and prolonged fasting
- Gastrointestinal losses, which occur through conditions like chronic diarrhea, malabsorption syndromes, inflammatory bowel disease, celiac disease, short bowel syndrome, and pancreatitis
- Medications, particularly loop and thiazide diuretics, proton pump inhibitors, certain antibiotics, immunosuppressants, and some chemotherapy agents
- Endocrine disorders, such as hyperaldosteronism, hyperthyroidism, and hyperparathyroidism, which can increase renal magnesium wasting
- Other causes, including diabetic ketoacidosis, severe burns, excessive sweating, pregnancy, lactation, and genetic disorders like Gitelman syndrome and Bartter syndrome Critically ill patients are especially vulnerable due to multiple risk factors, as noted in the study 1. It is essential to note that hypomagnesemia is clinically significant because magnesium is essential for numerous enzymatic reactions, neuromuscular function, and cardiac electrical stability, with deficiency potentially causing serious neurological and cardiovascular complications, as highlighted in the study 1. In terms of prevention and treatment, the study 1 suggests that modulating KRT fluid composition may represent the most appropriate therapeutic strategy to prevent KRT-related electrolytes derangements, including hypomagnesemia. The study 1 recommends correcting water and sodium depletion, using oral magnesium preparations, reducing excess lipid in the diet, and using oral 1-alpha cholecalciferol to prevent hypomagnesemia. Additionally, the study 1 emphasizes the importance of paying special attention to sodium, potassium, and magnesium balance in patients with a short bowel, and recommends using a glucose-saline replacement solution to maintain sodium balance. The study 1 suggests that rehydration to correct secondary hyperaldosteronism is the most important first step in managing hypomagnesemia, and recommends using magnesium oxide supplements, which contain more elemental magnesium than other salts.
From the FDA Drug Label
Magnesium Sulfate Injection, USP is suitable for replacement therapy in magnesium deficiency, especially in acute hypomagnesemia accompanied by signs of tetany similar to those observed in hypocalcemia. In total parenteral nutrition (TPN), magnesium sulfate may be added to the nutrient admixture to correct or prevent hypomagnesemia which can arise during the course of therapy. Early symptoms of hypomagnesemia (less than 1. 5 mEq/L) may develop as early as three to four days or within weeks. Hypocalcemia and hypokalemia often follow low serum levels of magnesium.
The causes of hypomagnesemia include:
- Magnesium deficiency
- Total parenteral nutrition (TPN), which can lead to hypomagnesemia during the course of therapy 2 No other direct causes of hypomagnesemia are mentioned in the provided drug labels. 2
From the Research
Causes of Hypomagnesemia
The causes of hypomagnesemia can be categorized into several groups, including:
- Inadequate magnesium intake 3, 4
- Increased gastrointestinal losses, such as chronic watery diarrhea, steatorrhea, short bowel syndrome, bowel fistula, and continuous nasogastric suctioning 4
- Increased renal losses, which can be caused by genetic or acquired renal disorders, such as Bartter's syndrome, Gitelman's syndrome, and renal transplantation 3, 4
- Redistribution of magnesium from extracellular to intracellular space 3
- Cellular redistribution of magnesium, which can occur in various conditions, including metabolic acidosis and insulin deficiency 4
- Use of certain therapeutic agents, such as loop and thiazide diuretics, aminoglycosides, cisplatin, pentamidine, and foscarnet, which can cause renal magnesium wasting and subsequent deficiency 4, 5
Specific Conditions Associated with Hypomagnesemia
Certain conditions are associated with an increased risk of hypomagnesemia, including:
- Alcoholism and diabetes, in which a combination of factors contributes to magnesium deficiency 4
- Thiazide diuretic use, which is associated with lower serum magnesium levels and an increased risk of hypomagnesemia 5
- Loop diuretic use, which is not associated with an increased risk of hypomagnesemia, but rather with higher serum magnesium levels 5
- Familial renal magnesium wasting, which is associated with hypercalciuria, nephrocalcinosis, and nephrolithiasis 3
- Gitelman syndrome, which is associated with hypokalemia, metabolic alkalosis, renal magnesium wasting, hypomagnesemia, and hypocalciuria 3
- Barter syndrome, which is associated with hypokalemia, metabolic alkalosis, renal magnesium wasting, hypomagnesemia, and hypercalciuria 3