ISSN: 1305-3876
Dil: Türkçe
Hakkında: Özel sayılar şeklinde yayınlanır.
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Hypophosphatemic States
Dr. Rıfat EMRALa
aEndokrinoloji ve Metabolizma Hastalıkları BD, Ankara Üniversitesi Tıp Fakültesi, ANKARA
Low serum phosphate concentrations are found in 5-10% of all hospitalized patients (2.5 mg/dl). A smaller percentage have found profound hypophosphatemia (<1 mg/dl). Major mechanisms by which hypophosphatemia can occur are, redistribution of phosphate from the extracellular fluid into cells, decreased intestinal absorption of phosphate and increased urinary phosphate excretion. The diagnosis of hypophosphatemia is often evident from the history. If, however, the diagnosis is not apparent, then measurement of urinary phosphate excretion should be helpful. If the function of kidney is normal and if it responds phosphate wasting normally, daily phosphate excretion should be less than 100 mg and the fractional excretion of phosphate should be well below 5% (normal value is 5 to 20%). At this point the differential diagnosis of hypophosphatemia includes cellular uptake and reduced net intestinal absorption. Urinary phosphate excretion above 100 mg/da yor a fractional excretion of phosphate above 5% is indicative of renal phosphate wasting. This could be due either to hyperparathyroidism or to a renal tubular defect. Symptoms of hypophosphatemia rarely occur unless the plasma phosphate concentration is less than 2 mg/dl. Moreover, the serious symptoms such as rhabdomyolysis are not seen until the plasma phosphate concentration falls below 1 mg/dl. For these reasons, most hypophosphatemic patients will not require therapy. Phosphate supplementation is indicated in patients who are symptomatic or who have a renal tubular defect leading to chronic phosphate wasting. Oral phosphate replacement is preferred with 2.5 t0 3.5 grams (80 to 110 mmol) being given per day in divided doses. In the symptomatic patients, if intravenous therapy is necessary, the dose should not exceed 2.5 mg/kg (0.08 mmol/kg) of body weight over 6 hours. The plasma phosphate concentration should be monitored every 6 hours and the patient switched to oral replacement when a level of 2 to 2.5 mg/dl (0.64 to 0.80 mmol/L) is reachedKeywords: Phosphate, hypophosphatemiaTurkiye Klinikleri J Surg Med Sci 2006, 2(7):64-67
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