Hypermagnesemia is uncommon but may occur if certain risk factors are present. It occurs when delivery of magnesium is excessive and/or the ability to eliminate it is impaired.


Sources of magnesium:

(1) intravenous magnesium infusions

(2) magnesium salt cathartics

(3) magnesium salt antacids

(4) magnesium salt in dialysate (during dialysis)


Usual patients at risk:

(1) neonate or elderly

(2) acute or chronic renal insufficiency

(3) intestinal disorders, especially if excessive doses have been given to relieve constipation and/or obstruction

(4) laxative abuse (eating disorder, other)

(5) poisoned patient treated with multiple doses of magnesium salt cathartics, especially if catharsis does not occur because of decreased bowel motility or obstruction

(6) error in parenteral administration (wrong dose calculation, wrong ampule given)

(7) pregnant woman with eclampsia


Less frequent settings (Ellenhorn, page 1586):

(1) lithium therapy

(2) hypothyroidism

(3) viral hepatitis

(4) hyperparathyroidism

(5) pituitary dwarfism

(6) milk-alkali syndrome

(7) acute diabetic ketoacidosis or diabetic coma

(8) Addison's disease

(9) malignant neoplasms with skeletal involvement


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