What Is Hypophosphatemic Osteomalacia?

Phosphorus concentration in circulating blood is lower than normal. Present hemolysis, burnout, weakness, and convulsions. A class of phosphorus metabolism disorders, also known as hypophosphatemia.

Phosphorus concentration in circulating blood is lower than normal. Present hemolysis, burnout, weakness, and convulsions. A class of phosphorus metabolism disorders, also known as hypophosphatemia.

nickname

Hypophosphatemia

Visiting department

Endocrinology

Common causes

Due to fasting, long-term use of binders such as aluminum hydroxide, magnesium hydroxide or aluminum carbonate, glycolysis and alkalosis.

Common symptoms

Central nervous system symptoms such as paresthesia, dysarthria, tremor, etc.

Contagious

no

Hypophosphatemia I. Causes and common diseases:

The general diet contains sufficient phosphate. However, hypophosphatemia can occur in the following situations:

1. Fasting, especially in patients with intravenous hypertrophy, because glucose can increase the uptake of phosphate by cells, leading to hypophosphatemia.

2. Take a long-term combination of aluminum hydroxide, magnesium hydroxide or aluminum carbonate to inhibit the intestinal absorption of phosphate.

3. Glycolysis and alkalosis can quickly consume the concentration of phosphate in the cell, increase the intake of phosphate by the cell, and cause hypophosphatemia. After diabetic acidosis patients are treated with insulin, glycolysis increases and phosphates move into the cells.

4. Hyperparathyroidism, increased parathyroid hormone secretion, and increased urinary phosphate excretion.

5. Vitamin D deficiency reduces the absorption of intestinal phosphate.

6. In some renal tubular diseases, such as Fanconi's syndrome, urine phosphate excretion is significantly increased.

7. Alcoholism causes hypophosphatemia due to reduced diet, increased glycolysis, and treatment of gastritis with antacid binders.

8. Anti-Vitamin D rickets (familial hypophosphatemia), sexually linked dominant genetic diseases, impaired reabsorption of phosphorus in proximal tubules, and poor absorption of intestinal calcium.

Hypophosphatemia 2. Differential diagnosis:

The symptoms of hypophosphatemia are: Central nervous system symptoms, such as paresthesia, dysarthria, hyperreflexia, tremor, ataxia, and coma. Due to the decrease of 2,3-bisphosphoglycerate of red blood cells, the life span of red blood cells is shortened, and erythrocyte disease and hemolysis can be manifested. fatigue, muscle weakness, muscle pain, and even paralysis. Bone pain (due to osteomalacia), false fractures can be seen on X-ray films. Dysfunction of phagocytosis of leukocytes, prone to infection. Platelet dysfunction and decreased platelet aggregation ability.

The most common cause of hypophosphatemia is alkalosis (respiratory and metabolic). Generally, hypophosphatemia can be identified according to the following procedure: After eliminating the cause of alkalosis, the urine phosphate is determined. If the excretion of urinary phosphate is increased, the plasma calcium is measured. Increase in plasma calcium, consider primary hyperparathyroidism, ectopic parathyroid, malignant tumors; if plasma calcium is normal or decreased, consider secondary hyperparathyroidism, rickets or osteomalacia, Fan Ke Nissl syndrome, hypophosphatemic chondropathy. Decreased excretion of urinary phosphate should consider reduced phosphate intake in the diet, antacid therapy, and insulin therapy.

Hypophosphatemia III. Examination:

(1) X-ray examination of bone:

The X-ray image itself is a direct reflection of the absorption of X-rays by the tissue, and the amount of X-rays absorbed by the tissue under the same irradiation conditions depends on the density and thickness of the tissue. Therefore, when there is a comparison standard of bone absorption X-rays, the actual bone density of the examinee can be compared according to the results of the X-ray bone densitometer.

(B) urine test:

Urinary phosphorus increased, calcium and magnesium in urine were normal or slightly lower, and cAMP in urine was normal.

(Three) blood biochemical examination:

Blood phosphorus is low, usually 0.32 to 0.78 mmol / L (1 to 2.4 mg / dl). Blood calcium and magnesium are normal or slightly lower, and the product of blood calcium and phosphorus is below 30. Blood alkaline phosphatase is elevated during the active phase. Blood parathyroid hormone (PTH) is normal or slightly higher, and blood 1,25 (OH) 2D3 levels are also more normal, but there are also decreases.

Hypophosphatemia IV. Principles of treatment:

Hypophosphatemia can be corrected by intravenous fluid replacement and phosphate replacement. Commonly used phosphates are a mixture of potassium dihydrogen phosphate (KH ₂ PO ₄ ) and disodium hydrogen phosphate (Na ₂ HPO ₄ ). If hypercalcemia is concurrent, in order to prevent the formation of displacement calcification, the intravenous supply of phosphate should be reduced. In addition, intravenous phosphate supplementation can cause the following complications: hypocalcemia. Displacement of calcification. Iatrogenic hyperkalemia and hypernatremia (caused by phosphate supplementation). At the same time, the cause of hypophosphatemia should be treated.