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What Is Hypophosphatemia?

Medically Reviewed by Dan Brennan, MD on June 20, 2021

Phosphorous is a mineral found in your bones that helps to keep your bones and body healthy. Normal blood phosphorous levels are between 2.5 to 4.5 mg/dL. Hypophosphatemia is a condition in which your blood has a low level of phosphorous. Low levels can cause a host of health challenges, including muscle weakness, respiratory or heart failure, seizures, or comas. The cause of hypophosphatemia is always from some other underlying issue. It is a severe condition, and you must treat the underlying issue to prevent some of the very severe repercussions of having hypophosphatemia. 

Causes of Hypophosphatemia

There are two different types of hypophosphatemia; acute and chronic. Both of their causes are different. Acute hypophosphatemia comes on very quickly, whereas chronic hypophosphatemia develops slowly over a long period of time. 

Acute Hypophosphatemia‌

Acute hypophosphatemia is usually the more severe and common type of hypophosphatemia seen in clinical settings. Its causes include:

  • Recovery from diabetic ketoacidosis. Diabetic ketoacidosis happens when someone mismanages their diabetes or might not realize they have it. It is a state that the body goes into when it is unable to produce enough insulin. Insulin is what helps your body break fat down and burn it as fuel. When you go into diabetic ketoacidosis, you have a buildup of acids in your bloodstream, leading to loss of consciousness or even death. 
  • Chronic Alcoholism. It is believed that over time, alcoholism hampers your kidney’s ability to absorb phosphorus fully. This is one of the most common causes of hypophosphatemia. Fifty percent of people who are hospitalized due to alcoholism develop hypophosphatemia within the first three days of their hospitalization. 
  • Burns. Phosphate is a source of intracellular energy, and when someone experiences a severe burn, their phosphate levels dip dangerously low. Therefore, patients must receive supplemental phosphate to stay healthy.
  • Respiratory alkalosis. This is a decreased amount of carbon dioxide pressure without increased bicarbonate. It usually happens when you hyperventilate or simply breathe in and out too quickly. Respiratory alkalosis causes acute hypophosphatemia because your cells naturally begin to shift around the phosphate stores in your bones. This cause of acute hypophosphatemia is different than the other causes because it will immediately return to normal once the hyperventilation stops. 

Chronic Hypophosphatemia‌

Typically, chronic hypophosphatemia is caused by issues with the kidneys and their ability to absorb phosphorus:

  • Malnutrition/semistarvation. Long-term starvation, malnutrition, and anorexia can deplete the body’s stores of phosphorous over time. Acute hypophosphatemia is especially common in hospital patients undergoing refeeding. Additional causes include chronic infections, Crohn’s disease, or malignant tumors.
  • Hyperparathyroidism. Glands located near the thyroid called parathyroids produce a hormone that signals to the body how much phosphorous it needs. Hyperparathyroidism causes the body to over excrete this hormone and give away far too much phosphorus than is necessary.
  • Hormonal conditions. Things like Cushing syndrome or hypothyroidism can impact the body in the same or similar ways as hyperparathyroidism. For example, they can cause the body to send abnormal levels of phosphorous into the bloodstream.
  • Vitamin D deficiency.Vitamin D deficiency impairs bone health and the bones’ ability to mineralize themselves.
  • Issues with electrolytes. Disorders like hypomagnesemia and hypokalemia that affect the body's ability to both generate and absorb electrolytes can also cause acute hypophosphatemia.
  • Diuretics and antacids. Long-term use of diuretics and antacids can significantly impact the kidney’s ability to absorb phosphorous.

Symptoms

As stated previously, hypophosphatemia is always caused by an underlying condition. However, often it is asymptomatic. Some of the tell-tale signs you might have hypophosphatemia, include: 

Most people with hypophosphatemia don’t immediately present as having hypophosphatemia. Healthcare providers need to pay attention to the patient’s medical history to detect hypophosphatemia.

Treatment

Hypophosphatemia affects the entire body, even on an intracellular level. If gone untreated, it can result in:

  • Bone diseases like rickets, osteopenia, osteoporosis, and osteomalacia
  • Altered mental states
  • Irritability 
  • Pins and needles feeling in the body
  • Numbness
  • Seizures
  • Coma
  • Heart failure
  • Lessened function of the diaphragm
  • Deficiency of white blood cells
  • Lessened immunity

Hypophosphatemia can even lead to death. That is why it is so important to treat it, even if the symptoms do not present very severely. Treating hypophosphatemia involves supplementing phosphorous in amounts that depend on the severity of your condition.

Mild cases should be treated with oral phosphorous supplementation of up to 80 mmol per day. More severe cases should be treated with up to .48 mmol/L intravenous supplementation. 

WebMD Medical Reference

Sources

SOURCES:

Advanced Studies in Medicine: “Hypophosphataemia in Respiratory Alkalosis.”

Annals of Burns and Fire Disasters: “Hypophosphataemia in Burns.”

Journal of Clinical Medicine: “Magnesium, Calcium, Potassium, Sodium, Phosphorus, Selenium, Zinc, and Chromium Levels in Alcohol Use Disorder: A Review.”

Mayo Clinic: “Diabetic Ketoacidosis,” “Hyperparathyroidism.”

Merck Manual: “Hypophosphatemia,” “Respiratory Alkalosis,” “Vitamin D Deficiency and Dependency.”

National Kidney Foundation: “Phosphorous and Your Diet.”

Postgraduate Medical Journal: “Hypophosphatemia in anorexia nervosa.”

StatPearls: “Hypophosphataemia.”

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