Hypophosphatemia (Low Level of Phosphate in the Blood)

ByJames L. Lewis III, MD, Brookwood Baptist Health and Saint Vincent’s Ascension Health, Birmingham

Reviewed/Revised Sep 2023

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In hypophosphatemia, the level of phosphate in blood is too low.

Symptoms|
Diagnosis|
Treatment|

Phosphate is one of the body's electrolytes, which are minerals that carry an electric charge when dissolved in body fluids such as blood, but the majority of phosphate in the body is uncharged.

Hypophosphatemia may be

Acute
Chronic

Acute hypophosphatemia

In acute hypophosphatemia, the phosphate level in blood suddenly falls dangerously low. Because the body uses large amounts of phosphate during recovery from certain disorders, acute hypophosphatemia may occur in people recovering from the following conditions:

Severe undernutrition (including starvation)
Diabetic ketoacidosis
Severe alcohol use disorder
Severe burns

This sudden drop in phosphate level may result in an abnormal heart rhythm and even death.

Chronic hypophosphatemia

In chronic hypophosphatemia, the phosphate level in blood becomes low over time. Chronic hypophosphatemia usually develops because too much phosphate is excreted. Causes include the following:

Hyperparathyroidism
Chronic diarrhea
Use of diuretics for a long time
Use of large amounts of aluminum-containing antacids for a long time
asthma)

Symptoms of Hypophosphatemia

Symptoms of hypophosphatemia occur only when the phosphate level in blood becomes very low. Muscle weakness develops, followed by stupor, coma, and death.

In mild chronic hypophosphatemia, the bones can weaken, resulting in bone pain and fractures. People may become weak and lose their appetite.

Diagnosis of Hypophosphatemia

Measurement of phosphate levels in the blood

Hypophosphatemia is diagnosed when blood tests show that the level of phosphate in the blood is low. Doctors do other tests to identify the cause if it is not readily apparent.

Treatment of Hypophosphatemia

Increase phosphate intake

Medications that reduce the phosphate level are stopped.

If hypophosphatemia is mild and causes no symptoms, drinking low-fat or skim milk, which provides a large amount of phosphate, may help. Or people can take phosphate by mouth, but doing so usually causes diarrhea.

If hypophosphatemia is very severe or if phosphate cannot be taken by mouth, phosphate may be given by vein (intravenously).

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