Hypomagnesemia is a lower-than-normal magnesium level in the blood. Low serum
levels of magnesium can be due to lack of sufficient intake or absorption (malnutri-
tion, vomiting, diarrhea, celiac disease, Crohn’s disease), excess excretion of mag-
nesium (renal loss, chronic alcohol intake, diuretic use, aminoglycoside antibiotics,
antineoplastics), or intracellular movement of magnesium (ascites, hyperglycemia,
insulin administration). The cell membranes become more excitable in the setting of
low magnesium levels. Patients may also have associated imbalances of potassium
and calcium.
PROGNOSIS
Correction of the magnesium level is necessary to return normal electrolyte bal-
ance to the patient. Correction or management of the underlying condition may be
necessary to correct the magnesium level. Nerve impulse transmission is increased
in patients with hypomagnesemia. As the magnesium level drops, the patient may
develop seizures or cardiac arrhythmias.
SIGNS AND SYMPTOMS
• Painful paresthesia (numbness and tingling)
• Hyperactive deep tendon reflexes—using a reflex hammer, strike tendon
at specific site to elicit response (patellar tendon, Achilles tendon, brachio-
radialis, bicep, or tricep)
• Muscle twitching
• Seizures due to irritability of nervous tissue in brain
• Confusion due to Central Nervous System (CNS) irritability
• Headaches
• Mood changes or irritability
• Decreased appetite, nausea, and constipation due to decreased gastrointestinal
motility
• Decreased bowel sounds and abdominal distention
• Arrhythmia, ectopic beats, ventricular arrhythmias
• Contraction of facial muscle after tapping facial nerve anterior to ear
(Chvostek’s sign) due to increased excitation of nerve and muscle cells if
concurrent hypocalcemia
• Carpal spasm after inflation of blood pressure cuff to upper arm—occludes
brachial artery and applies pressure to nerves (Trousseau’s sign) if concurrent
hypocalcemia
TREATMENT
• Administer magnesium sulfate intravenously to increase levels.
• Monitor deep tendon reflexes.
• Monitor cardiac rhythm.
• Increase magnesium in the patient’s diet.
• May need to correct calcium and potassium concurrently.
NURSING DIAGNOSES
• Impaired gas exchange
• Risk for injury
• Decreased cardiac output
NURSING INTERVENTION
• Monitor intake and output.
• Monitor vital signs for changes.
• Monitor cardiovascular status for changes in heart rhythm, pulse deficit.
• Explain to the patient:
• Eat whole grains, legumes, fish, and dark green leafy vegetables that are
high in magnesium.
• No laxatives.
