Hypophosphatemia

Hypophosphatemia is a serum phosphate concentration <2.5 mg / dl (0.81 mmol / l). Causes are alcoholism, burns, hunger and the use of diuretics. The clinical symptoms are muscle weakness, respiratory failure, heart failure, seizures and coma. The diagnosis is made by determining the serum phosphate concentration. The therapy consists of a phosphate substitute.

(See also overview of disorders of phosphate concentration.)

Hypophosphatemia is a serum phosphate concentration <2.5 mg / dl (0.81 mmol / l). Causes are alcoholism, burns, hunger and the use of diuretics. The clinical symptoms are muscle weakness, respiratory failure, heart failure, seizures and coma. The diagnosis is made by determining the serum phosphate concentration. The therapy consists of a phosphate substitute. (See also overview of disorders of the phosphate concentration.) A hypophosphatemia occur in 2% of all hospitalized patients, but has in certain populations an increased prevalence (z. B. have up to 10% of all hospitalized alcoholic hypophosphatemia). Etiology Hypophosphatemia has a variety of causes; clinically relevant acute hypophosphatemia occurs in only a few clinical conditions, such as: In the recovery phase of diabetic ketoacidosis in acute alcoholism case of severe burns In total parenteral nutrition Upon return to normal diet after prolonged malnutrition In severe respiratory alkalosis Acute severe hypophosphatemia with a serum phosphate <1 mg / dl (<0.32 mmol / l) is usually caused by transcellular phosphate shifts in already existing chronic phosphate deficiency. Chronic hypophosphatemia is usually a result of reduced renal phosphate reabsorption. The causes include: increased parathyroid hormone levels, such as in primary and secondary hyperparathyroidism Other hormonal imbalances such. B. Cushing's syndrome and hypothyroidism vitamin D deficiency electrolyte imbalance such. B. hypomagnesemia and hypokalemia Theophyllinintoxikation Prolonged diuretics Severe chronic hypophosphatemia resulting from a prolonged negative phosphate balance. The causes include: chronic hunger states or malabsorption, often in patients with alcoholism, especially when combined with vomiting or severe diarrhea Prolonged intake of large amounts of phosphate-binding aluminum, usually in the form of antacids patients (with advanced chronic kidney disease in particular on dialysis ) often take a phosphate binder with meals to reduce the absorption of phosphate from food. The prolonged use of these binders can cause hypophosphatemia, especially in combination with greatly reduced food intake of phosphate. Symptoms and signs Although hypophosphatemia is usually asymptomatic, may occur in a severe, chronic lack anorexia, muscle weakness and osteomalacia. The same applies to serious neurological disorders such. As a progressive encephalopathy with convulsions, coma and death. The muscle weakness in severe hypophosphatemia can, especially in alcoholism, accompanied by rhabdomyolysis. The hematological symptoms of hypophosphatemia are hemolytic anemia, decreased oxygen release of hemoglobin and impairment of leucocytes and platelet function. Diagnostic serum phosphate levels Hypophosphatemia is diagnosed at a serum phosphate concentration <2.5 mg / dl (<0.81 mmol / l). Most causes of hypophosphatemia (z. B. diabetic ketoacidosis, burns, food structure) are obvious and easy to spot. When clinically indziert (z. B. suspicious liver or signs of liver cirrhosis in patients with suspected alcoholism), test can be performed to diagnose the cause. Treatment Treat the underlying disease Oral phosphate substitution Intravenous phosphate administration in serum phosphate <1 mg / dl (<0_32 mmol / l) or severe symptoms Oral Treatment In asymptomatic patients, even if the serum concentrations of phosphate are very low, the treatment of the underlying disease and oral substitution usually sufficient. Phosphate may p.o. in doses of up to 1 g are administered 3 times daily in the form of tablets consisting of sodium phosphate or potassium phosphate. Oral sodium phosphate or potassium phosphate can be poorly tolerated as it causes diarrhea. One liter of reduced fat or skim milk containing 1 g of phosphate, and is much better tolerated. Tackling the causes of hypophosphatemia may settling phosphate binding antacids, ending diuretics or correction of hypomagnesemia umfassen.Parenterale treatment Parenteral phosphate iv usually given. They should be applied in the following cases: If serum phosphate is <1 mg / dl (<0_32 mmol / l) rhabdomyolysis, hemolysis, or CNS symptoms are Oral substitution is not possible due to the underlying disease, the i.v. Administration of potassium phosphate (as buffered solution of K2HPO4 and KH2PO4) is considered safe when renal function is good. Parenteral potassium phosphate containing 93 mg (3 mmol) of phosphorus and 170 mg (4.4 mEq) of potassium per ml. The usual dose is 0.5 mmol phosphorus / kg (0.17 ml / kg) i.v. h over. 6 Patients with alcoholism may have a need of ? 1 g / day for parenteral nutrition. The additional intravenous phosphate transfer is stopped when oral intake is adequate. When patients have impaired renal function or serum potassium is> 4 mmol / l, should be used in general sodium phosphate preparations; these preparations contain 3 mmol / ml of phosphorus oxychloride and are therefore administered in the same dose. Serum calcium and -Phosphatkonzentrationen should be monitored during treatment, particularly when phosphate is administered intravenously or impaired renal function is known. In most cases, no more than 7 mg / kg (approximately 500 mg for an adult of 70 kg body weight) phosphate within 6 hours should be given. The emergence of hypocalcemia, hyperphosphatemia and metastatic calcification due to excessive calcium phosphate product can be prevented by a strict monitoring of therapy and avoiding faster infusion rates of phosphate. Summary Acute hypophosphatemia usually occurs in alcoholism, burns or starvation conditions. Acute severe hypophosphatemia can cause severe neuromuscular disorders, rhabdomyolysis, seizures, coma and death. Chronic hypophosphatemia, by hormonal disorders (such. As hyperparathyroidism, Cushing’s syndrome, hypothyroidism), chronic administration of diuretics or use of aluminum-containing antacids are caused in patients with chronic kidney disease. Hypophosphatemia is usually asymptomatic, but can cause in a severe deficiency anorexia, muscle weakness and osteomalacia. The underlying condition is treated, but some patients require oral, intravenous or rarely, phosphate substitution.

Health Life Media Team

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