From the Guidelines
Hypomagnesemia in pediatric patients is primarily caused by inadequate intake, increased gastrointestinal losses, and increased renal losses, with factors such as malnourishment, chronic diarrhea, and certain medications like diuretics and aminoglycosides playing a significant role. According to the most recent and highest quality study available, 1, magnesium homeostasis is crucial in pediatric patients, and intakes and renal function play a critical role in maintaining normal magnesium levels. The study highlights that intestinal absorption rate is usually between 35 and 50%, and magnesium retention is usually around 0.08 mmol/kg/d in infants fed human milk and up to 0.15 mmol/kg/d in premature infants fed enriched preterm infant formulas.
Some of the key causes of hypomagnesemia in pediatric patients include:
- Inadequate intake, which can occur in malnourished children or those receiving prolonged parenteral nutrition without proper magnesium supplementation
- Increased gastrointestinal losses, common in conditions like chronic diarrhea, malabsorption syndromes, and short bowel syndrome
- Increased renal losses, resulting from medications such as loop and thiazide diuretics, aminoglycosides, and certain genetic disorders like Gitelman syndrome and Bartter syndrome
- Redistribution within the body, which can occur during refeeding syndrome, diabetic ketoacidosis treatment, and insulin administration, as well as in critical illness, burns, and pancreatitis, as mentioned in 1.
It is essential to address the underlying cause of hypomagnesemia and provide magnesium supplementation, typically with magnesium sulfate or magnesium oxide, with dosing based on severity and the child's age and weight, as suggested by 1. Additionally, the study emphasizes the importance of adapting magnesium intakes to postnatal blood concentrations in preterm infants exposed to maternal magnesium therapy, highlighting the need for careful monitoring and management of magnesium levels in pediatric patients.
From the FDA Drug Label
As a nutritional adjunct in hyperalimentation, the precise mechanism of action for magnesium is uncertain. Early symptoms of hypomagnesemia (less than 1. 5 mEq/L) may develop as early as three to four days or within weeks. The causes of hypomagnesemia in pediatrics are not directly stated in the provided drug label. Hypomagnesemia can lead to neurological effects, such as:
- Muscle irritability
- Clonic twitching
- Tremors It can also be associated with:
- Hypocalcemia
- Hypokalemia 2
From the Research
Causes of Hypomagnesemia in Pediatrics
- Inadequate magnesium intake
- Increased gastrointestinal or renal losses
- Redistribution from extracellular to intracellular space 3
- Genetic or acquired renal disorders, such as Barter syndrome and Gitelman syndrome, which can lead to renal magnesium wasting 3, 4
- Use of certain medications, including loop and thiazide diuretics, aminoglycosides, cisplatin, pentamidine, and foscarnet, which can cause renal magnesium wasting 3, 5, 6
- Gastrointestinal causes, such as protein-calorie malnutrition, chronic watery diarrhea, steatorrhea, short bowel syndrome, and bowel fistula 5
- Cellular redistribution of magnesium, which can occur in certain conditions, such as alcoholism and diabetes 5
Genetic Causes of Hypomagnesemia
- Familial renal magnesium wasting, which can be caused by mutations in several genes, including CLDN16, CLDN19, CASR, and CLCNKB 4
- Gitelman-like hypomagnesemias, which can be caused by mutations in genes such as SLC12A3, BSND, and KCNJ10 4
- Mitochondrial hypomagnesemias, which can be caused by mutations in genes such as SARS2 and MT-TI 4
- Other hypomagnesemias, which can be caused by mutations in genes such as TRPM6, CNMM2, and FAM111A 4