Magnesium deficiency
Introduction
Introduction to magnesium deficiency When magnesium is <0.75mmol/L, it is called magnesium deficiency, also called hypomagnesemia. Magnesium is one of the essential elements of the human body. The content of magnesium in the cations of the cells is second only to potassium. Magnesium is widely present in various tissues in the body, and participates in many biological processes, and has the function of maintaining muscle contractility and nerve stress. It can activate many enzymes in the body and promote energy metabolism. The normal concentration of serum magnesium is 0.801.20mmol/L, and its regulation is mainly completed by the kidney. The magnesium excretion of the kidney is similar to that of potassium. Even if the serum magnesium concentration is lowered, the magnesium excretion of the kidney does not stop. In many diseases, abnormalities in magnesium metabolism often occur. basic knowledge The proportion of sickness: 0.01% Susceptible people: no special people Mode of infection: non-infectious Complications: Epilepsy Arrhythmias
Cause
Cause of magnesium deficiency
Excessive loss of digestive tract and insufficient supplementation (45%):
Due to magnesium absorption in the small intestine and part of the colon, when severe diarrhea, steatorrhea, malabsorption, intestinal fistula, most small bowel resection, etc. can cause hypomagnesemia; in malnutrition, some diseases nutritional support solution in magnesium Insufficient, or even long-term use of magnesium-free solution.
Excessive kidney loss (20%):
Such as chronic pyelonephritis, renal tubular acidosis, acute renal failure, polyuria, or long-term use of loop diuretics, thiazide and osmotic diuretic, such as renal magnesium loss and hypomagnesemia.
Hyperthyroidism (8%):
Patients with hyperthyroidism often have low blood magnesium and negative nitrogen balance, and primary hyperparathyroidism can cause symptomatic magnesium deficiency.
Prevention
Magnesium deficiency prevention
Prevention of hypomagnesemia
Patients with hypomagnesemia may be given prophylactic doses of magnesium as early as possible. For example, patients who are treated with parenteral nutrition should be supplemented with magnesium. Patients who have long-term use of diuretics and have a poor diet should also be supplemented with magnesium. Regularly monitor the level of magnesium ions.
Complication
Magnesium deficiency complications Complications epilepsy arrhythmia
Common complications of this disease:
1. Memory loss.
2. Epileptic seizures.
3. Arrhythmia.
Hypomagnesemia is easy to be associated with hypokalemia and hypocalcemia. When low magnesium causes hand and foot convulsions, low calcium and low potassium are often concerned, so unexplained hypokalemia and hypocalcemia are found. No presence of hypomagnesemia. Hypokalemia is associated with low calcium, low magnesium, low calcium, often manifested as hand and foot spasm, and their symptoms can also be confused with each other. Attention should be paid to the supplement of appropriate calcium and magnesium while supplementing potassium.
Symptom
Symptoms of magnesium deficiency common symptoms nausea and unconsciousness hypokalemia irritability, irritability, nervousness, arrhythmia, anorexia, hypomagnesemia
Early magnesium deficiency often has anorexia, nausea, vomiting, weakness and apathy. Magnesium deficiency may have memory loss, nervousness, irritability, unconsciousness, irritability, movements of the hands and feet, and severe magnesium deficiency. There is an epileptic seizure, which is often accompanied by potassium deficiency and calcium deficiency due to magnesium deficiency, so it is difficult to determine which symptoms are caused by magnesium deficiency.
In addition, hypomagnesemia can cause arrhythmia, magnesium is essential for the activation of Na+ K+ ATPase, magnesium deficiency can cause potassium loss in cardiomyocytes, ECG can show prolongation of PR and QT interval, QRS wave widens, ST segment Decreased, T wave widened, low or inverted, occasionally U wave, confused with hypokalemia, or related to blood potassium, blood calcium changes.
Examine
Magnesium deficiency check
Determination of serum magnesium
Hypomagnesemia can be diagnosed when serum magnesium is <0.75mmol / L. However, it cannot be used as a reliable indicator of magnesium deficiency in the signal transduction of anti-cardiomyocytes. In addition, blood magnesium is also affected by pH proteins and a variety of factors.
2. Determination of urinary magnesium
If clinically estimated to have magnesium deficiency and normal blood magnesium, urine magnesium should be measured. Magnesium deficiency can be diagnosed when the 24h urinary magnesium output is less than 1.5mmol.
3. Determination of intracellular magnesium in tissues
The measurable red blood cell magnesium and the intramuscular magnesium ratio reflect the changes in magnesium in the body more accurately, but the examination method is complicated.
4. Intravenous magnesium load test
Inject 500 ml of sugar solution containing 30 mmol of magnesium sulfate in 12 h, collect 24 hours of urine, and measure the urinary magnesium output. If the input magnesium is >50%, the magnesium is retained in the body, and <30% retention can eliminate magnesium deficiency. . This test should not be used in patients with renal insufficiency or D-responders or respiratory insufficiency.
Diagnosis
Diagnosis and differential diagnosis of magnesium deficiency
diagnosis
Diagnosis can be based on the cause, symptoms and related tests.
Differential diagnosis
Intestinal malabsorption
The symptoms of primary disease are obviously easy to diagnose and often caused by comprehensive factors. In addition to low renal tubular blood magnesium, intestinal absorption disorders are often accompanied by hypokalemia and low calcium, low sodium, low chloride and low phosphorus and metabolic acidosis.
Parathyroid dysfunction
In patients with primary hyperparathyroidism, the magnesium retention function of the kidney is reduced due to hypercalcemia, so urinary magnesium is increased in the case of congestive heart failure with hypomagnesemia. Hypomagnesemia can also occur after removal of the parathyroid gland due to the deposition of magnesium on bone tissue. Therefore, urinary magnesium does not increase the latter, hypomagnesemia combined with low calcium, and low calcium occurs when hand and foot convulsions, magnesium supplementation is difficult to control if only calcium supplementation.
Congestive heart failure
Primary refractory ketosis
Increased aldosterone secretion and increased urinary magnesium excretion, leading to hypomagnesemia, the primary features are generally not difficult to diagnose.
Diabetic acidosis
Heart disease
Found in congestive heart failure chronic pulmonary heart disease, alcoholic cardiomyopathy, acute myocardial infarction and systemic surgery and after surgery
