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Hypermagnesemia
Classification & external resources

Magnesium
ICD-10	E83.4
ICD-9	275.2
DiseasesDB	6259
eMedicine	med/3383  emerg/262 ped/1080

Hypermagnesemia is an electrolyte disturbance in which there is an abnormally elevated level of magnesium in the blood. Usually this results in excess of magnesium in the body.

Hypermagnesemia occurs rarely because the kidney is very effective in excreting excess magnesium. It usually develops only in people with kidney failure who are given magnesium salts or who take drugs that contain magnesium (e.g. some antacids and laxatives). It is usually concurrent with hypercalcemia and/or hyperkalemia.

Contents 1 Metabolism 2 Symptoms 3 Causes 3.1 Predisposing conditions 4 Therapy

For a detailed description of magnesium homeostasis and metabolism see hypomagnesemia.

• Weakness, nausea and vomiting
• Hypotension
• Impaired breathing
• Arrhythmia and asystole, most prominent cardiac symptoms are due to conduction delays, since magnesium acts as physiologic calcium blocker.

Clinical consequences related to serumconcentration:

• 4.0 mEq/l hyporeflexia
• >5.0 mEq/l Prolonged atrioventricular conduction
• >10.0 mEq/l Complete heart block
• >13.0 mEq/l Cardiac arrest

Since magnesium is excreted through the kidneys renal failure can result in hypermagnesemia. The most important cause however is suppletion.

• Hemolysis, magnesium concentration in erythrocytes is approximately three times greater than in serum, therefore hemolysis can increase plasma magnesium. Hypermagnesemia is expected only in massive hemolysis.
• Renal insufficiency, excretion of magnesium becomes impaired when creatinine clearance falls below 30 ml/min. However, hypermagnesemia is not a prominent feature of renal insufficiency unless magnesium intake is increased.
• Other conditions that can predispose to mild hypermagnesemia are diabetic ketoacidosis, adrenal insufficiency, hyperparathyroidism and lithium intoxication.

Prevention of hypermagnesemia usually is possible. In mild cases, withdrawing magnesium suppletion is often sufficient. In more severe cases the following treatments are used:

• Intravenous calcium gluconate, because the actions of magnesium in neuromuscular and cardiac function are antagonized by calcium.

Definitive treatment of hypermagnesemia requires increasing renal magnesium excretion through:

• Intravenous diuretics, in the presence of normal renal function
• Dialysis, when kidney function is impaired and the patient is symptomatic from hypermagnesemia

v • d • e Metabolic pathology (E70-90)
Amino acid	Phenylketonuria - Alkaptonuria - Ochronosis - Tyrosinemia - Maple syrup urine disease - Propionic acidemia - Methylmalonic acidemia - Isovaleric acidemia - Primary carnitine deficiency - Cystinuria - Cystinosis - Hartnup disease - Homocystinuria - Citrullinemia - Hyperammonemia - Glutaric acidemia type 1
Carbohydrate	Lactose intolerance - Glycogen storage disease (type I, type II, type III, type IV, type V, type VI), Fructose intolerance, Galactosemia
Lipid	Lipid storage disorders Sphingolipidoses: Gangliosidosis - GM2 gangliosidoses (Sandhoff disease, Tay-Sachs disease) - GM1 gangliosidoses - Mucolipidosis type IV - Gaucher's disease - Niemann-Pick disease - Farber disease - Fabry's disease - Metachromatic leukodystrophy - Krabbe disease Neuronal ceroid lipofuscinosis (Batten disease) - Cerebrotendineous xanthomatosis - Cholesteryl ester storage disease (Wolman disease) Hyperlipidemia - Hypercholesterolemia - Familial hypercholesterolemia - Xanthoma - Combined hyperlipidemia - Lecithin cholesterol acyltransferase deficiency - Tangier disease - Abetalipoproteinemia
Mineral	Cu Wilson's disease/Menkes disease - Fe Haemochromatosis - Zn Acrodermatitis enteropathica - PO43− Hypophosphatemia/Hypophosphatasia - Mg2+ Hypermagnesemia/Hypomagnesemia - Ca2+ Hypercalcaemia/Hypocalcaemia/Disorders of calcium metabolism
Fluid, electrolyte and acid-base balance	Electrolyte disturbance - Na+ Hypernatremia/Hyponatremia - Acidosis (Metabolic, Respiratory, Lactic) - Alkalosis (Metabolic, Respiratory) - Mixed disorder of acid-base balance - H2O Dehydration/Hypervolemia - K+ Hypokalemia/Hyperkalemia - Cl− Hyperchloremia/Hypochloremia
Porphyrin and bilirubin	Acatalasia - Gilbert's syndrome - Crigler-Najjar syndrome - Dubin-Johnson syndrome - Rotor syndrome - Porphyria (Acute intermittent porphyria, Gunther's disease, Porphyria cutanea tarda, Erythropoietic protoporphyria, Hepatoerythropoietic porphyria, Hereditary coproporphyria, Variegate porphyria)
Glycosaminoglycan	Mucopolysaccharidosis - Hurler syndrome - Hunter syndrome - Sanfilippo syndrome - Morquio syndrome
Glycoprotein	I-cell disease - Pseudo-Hurler polydystrophy - Aspartylglucosaminuria - Fucosidosis - Alpha-mannosidosis - Sialidosis
Other	Alpha 1-antitrypsin deficiency - Cystic fibrosis - Familial Mediterranean fever - Lesch-Nyhan syndrome