Magnesium passes through the placental circulation, thus treatment of maternal eclampsia with magnesium can result in neonatal hypermagnesemia. Decreased GI elimination and increased GI absorption of magnesium can be caused by intestinal hypomotility from any cause. GI medications that decrease motility, including narcotics and anticholinergics. Hypomotility disorders like bowel obstruction and chronic constipation. Tumor lysis syndrome can release massive amounts of intracellular magnesium.
Adrenal insufficiency can cause secondary hypermagnesemia.
Rhabdomyolysis, like tumor lysis syndrome, can lead to the release of significant amounts of intracellular magnesium. Milk-alkali syndrome is associated with hypermagnesemia. Hypothyroidism Hypoparathyroidism Neoplasm with skeletal muscle involvement Lithium intoxication can produce associated hypermagnesemia. Hyperkalemia and hypercalcemia often are present concurrently. BUN and creatinine Order renal function tests and calculate creatinine clearance to assess the ability of the kidney to excrete magnesium.