Low phosphate levels in the blood (hypophosphatemia) are defined as blood phosphate concentrations of less than 2.5 mg/dL (0.81 mmol/L).
Treatment to increase phosphate levels consists of:
- Treatment of any underlying disorder that is causing low phosphate levels
- May include stopping phosphate-binding antacids or diuretics (never stop taking a prescribed medication without first talking to your doctor)
- Correcting low magnesium levels (hypomagnesemia)
- Oral phosphate replacement
- Can be given in doses up to about 1 g orally 3 times a day in tablets containing sodium phosphate or potassium phosphate
- Drinking one liter of low-fat or skim milk provides 1 g of phosphate and may be more acceptable for some patients since oral sodium phosphate or potassium phosphate may cause diarrhea
- Intravenous (IV) phosphate
- Given when blood phosphate level is less than 1 mg/dL (less than 0.32 mmol/L) or if symptoms are severe
What Are Symptoms of Hypophosphatemia?
Low phosphate levels in the blood (hypophosphatemia) often do not cause any symptoms.
In chronic or severe hypophosphatemia, symptoms may include:
- Loss of appetite
- Muscle weakness
- Softening of bones (osteomalacia)
- Respiratory failure
- Heart failure
- Progressive brain damage
- Muscle wasting (rhabdomyolysis)
- Hemolytic anemia
- Seizures
- Coma
What Causes Hypophosphatemia?
Low phosphate levels in the blood (hypophosphatemia) have numerous causes, such as:
- Recovery from diabetic ketoacidosis
- Alcohol use disorder
- Severe burns
- Receiving total parenteral nutrition (TPN)
- Refeeding after prolonged undernutrition
- Severe respiratory alkalosis
Chronic hypophosphatemia may be caused by:
- Hormonal disturbances
- Increased parathyroid hormone levels, such as primary and secondary hyperparathyroidism
- Cushing syndrome
- Hypothyroidism
- Vitamin D deficiency
- Electrolyte disorders
- Low magnesium levels (hypomagnesemia)
- Low potassium levels (hypokalemia)
- Long-term diuretic use
- Theophylline intoxication
Severe chronic hypophosphatemia may be cause by:
- Chronic starvation or difficulty digesting or absorbing nutrients from food (malabsorption)
- Frequently seen in patients with alcohol use disorder
- Long-term use of large amounts of phosphate-binding aluminum, usually in the form of antacids
- Patients with advanced chronic kidney disease (especially those on dialysis) often take phosphate binders which can lead to hypophosphatemia, especially when combined with decreased dietary intake of phosphate
How Is Hypophosphatemia Diagnosed?
Low phosphate levels in the blood (hypophosphatemia) are diagnosed with a blood test to check for blood phosphate concentration.
What Are Complications of Hypophosphatemia?
Complications of low phosphate levels in the blood (hypophosphatemia) depend on how severe and/or chronic the depletion is and may include:
- Seizures
- Delirium
- Coma
- Speech, vision, and hearing problems (focal neurologic findings)
- Heart failure
- Muscle wasting (rhabdomyolysis)
- Breakdown of red blood cells (acute hemolysis)
- White blood cell (leukocyte) dysfunction, which can increase susceptibility to infection
- Abnormal liver function tests
- Acute renal failure due to heart failure, rhabdomyolysis, and hemolysis
- Platelet dysfunction
- Glucose intolerance
- Metabolic acidosis
- Bone problems
- Rickets leading to short stature and significant bony deformities in children
- Softening of bones (osteomalacia) that can lead to severe bone pain and fractures in adults
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Reviewed on 11/17/2021
References
Image Source: iStock Images
https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hypophosphatemia
https://www.medscape.com/answers/242280-77043/what-are-the-possible-complications-of-hypophosphatemia
https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hypophosphatemia
https://www.medscape.com/answers/242280-77043/what-are-the-possible-complications-of-hypophosphatemia