Hypomagnesemia

Hypomagnesium - the concentration of magnesium in the plasma is less than 1.4 meq / l (<0.7 mmol / l).

Possible reasons include insufficient intake and absorption of magnesium, increased excretion due to hypercalcemia or the administration of preparations of the furosemide type. Symptoms of hypomagnesemia are associated with concomitant hypokalemia and hypocalcemia, include lethargy, tremor, tetany, convulsions, arrhythmias. Treatment is to compensate for magnesium deficiency.

[1], [2], [3], [4]

Causes of the hypomagnesemia

• Alcoholism - Due to inadequate intake and excess renal excretion
• Gastrointestinal loss - Chronic diabetes, steatorrhea
• Related to pregnancy - Pre-eclampsia and eclampsia, lactation (increased demand for magnesium)
• Primary renal losses - Excessive magnesium excretion without obvious cause (Gitelman syndrome)
• Secondary renal losses - Loop and thiazide diuretics; hypercalcemia; after removal of the parathyroid tumor; diabetic ketoacidosis; hypersecretion of aldosterone, thyroid hormones, ADH; nephrotoxins (amphotericin B, cisplatin, cyclosporine, aminoglycosides)

[5], [6], [7], [8], [9]

Symptoms of the hypomagnesemia

The concentration of magnesium in the plasma, even in the determination of free ions, can be within normal limits, despite the reduction in magnesium stores in cells or bone tissue. The decrease in magnesium content is usually caused by insufficient intake, as well as by impaired renal delay or LC absorption.

Symptoms of hypomagnesemia are the following: anorexia, nausea, vomiting, lethargy, weakness, personality disorder, tetany (eg, positive symptoms of Trusso or Tail or spontaneous carpopedic spasm), tremor and muscle fascination. Neurological signs, especially tetany, correlate with the development of concomitant hypocalcemia and / or hypokalemia. Electromyography determines myopathic potentials, but they are also characteristic of hypocalcemia or hypokalemia. Severe hypomagnesemia can cause generalized tonic-clonic convulsions, especially in children.

[10], [11]

Diagnostics of the hypomagnesemia

Diagnosis is based on the determination of  the serum magnesium level of  less than 1.4 meq / l (less than 0.7 mmol / l). Severe hypomagnesemia is usually observed at a level of less than 1.0 meq / L (less than 0.5 mmol / L). Associated hypocalcemia and hypocalcemia are often observed in patients with steatorrhea, alcoholism or other causes of magnesium deficiency. There may be hypokalemia with increased renal secretion of potassium and metabolic alkalosis. Thus, unexplained hypocalcemia and hypokalemia suggest a likelihood of a decrease in magnesium levels.

[12], [13]

Treatment of the hypomagnesemia

With asymptomatic magnesium deficiency or persistent with a level of less than 1.0 meq / L (less than 0.5 mmol / L) treatment with magnesium salts (sulfate or chloride) is indicated. Patients with alcoholism are treated empirically. In such cases, a deficit of up to 12-24 mg / kg is possible. Patients with normal renal function need a twice-calculated amount of calculated deficiency, since about 50% of the consumed magnesium is excreted in the urine. The intake of magnesium gluconate 500-1000 mg orally 3 times a day for 3-4 days. Parenteral administration is given to patients with severe hypomagnesemia or inability to enter. For parenteral administration, a 10% magnesium sulfate solution (1 g / 10 ml) for intravenous administration and a 50% solution (1 g / 2 ml) for intramuscular administration are used. During treatment, plasma magnesium levels need to be monitored, especially with parenteral administration or in patients with renal insufficiency. Treatment is performed until the normal level of magnesium in the plasma is reached.

In severe hypomagnesemia with significant symptoms (eg, generalized convulsions, magnesium levels less than 1 meq / L), intravenous administration of 2-4 g of magnesium sulfate is carried out for 5-10 minutes. If convulsions continue, the administration can be repeated up to a total dose of 10 g for the next 6 hours. If cramps are stopped, an infusion of 10 g in 1 liter of a 5% dextrose solution within 24 hours can be made, followed by administration of up to 2.5 g every 12 hours to compensate for the deficiency of total magnesium reserves and to prevent subsequent reduction in magnesium levels in the plasma. If the magnesium level in the plasma is below 1 meq / l (less than 0.5 mmol / l), but the symptoms are not so severe, you can intravenously administer magnesium sulfate in a 5% dextrose solution at a rate of 1 g per hour for up to 10 hours. In less severe cases of hypomagnesemia, gradual reimbursement can be achieved by parenteral administration of small doses for 3-5 days before the normalization of the plasma magnesium level.