In hypomagnesemia, the level of magnesium in blood is too low.
(See also Overview of Electrolytes and Overview of Magnesium's Role in the Body.)
Magnesium is one of the body's electrolytes, which are minerals that carry an electric charge when dissolved in body fluids such as blood, but the majority of magnesium in the body is uncharged and bound to proteins or stored in bone. Although blood contains very little magnesium, some is still necessary for normal nerve and muscle function and for development of bones and teeth. For healthy adults, the recommended daily intake of magnesium is 310 to 420 milligrams.
Causes of Hypomagnesemia
Usually, the magnesium level becomes low because people consume less (most often, because of starvation) or because the intestine cannot absorb nutrients normally (called malabsorption). But sometimes hypomagnesemia develops because the kidneys or intestine excrete too much magnesium.
Hypomagnesemia may also result from the following:
Consuming large amounts of alcohol (common), which reduces consumption of food (and thus magnesium) and increases excretion of magnesium
Protracted diarrhea (common), which increases magnesium excretion
High levels of aldosterone, vasopressin (antidiuretic hormone), or thyroid hormones, which increase magnesium excretion
Chronic use of a proton pump inhibitor (certain medications that reduce stomach acid)
Breastfeeding, which increases requirements for magnesium
Symptoms of Hypomagnesemia
Hypomagnesemia may cause nausea, vomiting, sleepiness, weakness, personality changes, muscle spasms, tremors, and loss of appetite. If severe, hypomagnesemia can cause seizures, especially in children.
Diagnosis of Hypomagnesemia
Measurement of the magnesium level in the blood
The diagnosis is usually based on blood tests indicating that the magnesium level is low. Hypocalcemia and hypokalemia also may be present.
Other tests may be needed to determine the cause of hypomagnesemia.
Treatment of Hypomagnesemia
Magnesium
Magnesium is given by mouth when the deficiency causes symptoms or persists. People with alcohol use disorder are usually given magnesium.
If a very low magnesium level is causing severe symptoms or if people cannot take magnesium by mouth, magnesium is given by injection into a muscle or vein.
When treating hypomagnesemia, doctors also must correct other electrolyte abnormalities, such as hypocalcemia and hypokalemia.
Underlying conditions that may cause hypomagnesemia are treated.
