Hypophosphatemia is an abnormally low level of phosphate in the blood. It tends to develop in people with serious conditions like sepsis or diabetic ketoacidosis. It can also occur with alcohol use disorder.

Phosphate is an electrolyte that helps your body with energy production and nerve function. Phosphate also helps build strong bones and teeth. You get phosphate from foods like milk, eggs, and meat.

Most of the phosphate in your body is housed in your bones. A much smaller amount is found inside your cells.

Hypophosphatemia can have many causes but tends to be more common in critically ill patients. Research shows it may affect as many as 15% of people in intensive care and as many as 80% of people with alcohol use disorder, diabetic ketoacidosis, or sepsis.

Read on to learn more about this condition, what causes it, and how it’s diagnosed and treated.

The most common causes of hypophosphatemia are:

  • inadequate phosphate intake
  • increased excretion of phosphates from the body
  • shift of phosphate from outside of cells into the space within cells

Acute hypophosphatemia is caused by phosphate transfer between cells alongside long-term depletion of the mineral. Chronic hypophosphatemia happens when the kidneys are not able to absorb as much phosphate.

In non-familial cases, acute hypophosphatemia can be triggered by conditions such as:

Chronic hypophosphatemia can be triggered by:

  • hormonal imbalances like hyperparathyroidism or Cushing syndrome
  • low magnesium, potassium, or vitamin D
  • use of the asthma medication theophylline
  • taking diuretics and a number of other types of medications
  • chronic starvation
  • chronic consumption of phosphate-binding aluminum or magnesium in antacids

Any of these triggers are also considered risk factors for hypophosphatemia.

Hypophosphatemia can be acute or chronic. In addition, hypophosphatemia can also be genetic. Familial hypophosphatemia is a rare form of the disease that can also lead to bone disease rickets and a softening of the bones called osteomalacia.

Familial hypophosphatemia has the following subtypes:

  • X-linked familial hypophosphatemia (XLH): This type may be the most common, though still rare, with a prevalence of 1 per 20,000 cases. Other sources suggest an even lower prevalence.
  • Autosomal dominant hypophosphatemic rickets (ADHR): This also affects about 1 per 20,000 newborns.
  • Hereditary hypophosphatemic rickets with hypercalciuria (HHRH): This is also characterized by high levels of calcium in the urine and has the lowest prevalence of about 1 per 250,000.

Many people with mild hypophosphatemia don’t have symptoms. Symptoms may not appear until your phosphate levels drop very low.

When symptoms do occur, they can include:

  • muscle weakness
  • fatigue
  • bone fractures
  • bone pain
  • appetite loss
  • irritability
  • numbness
  • confusion
  • slowed growth and shorter than normal height in children
  • tooth decay or late baby teeth (in familial hypophosphatemia)

A diagnosis of hypophosphatemia usually begins with a blood test. You’re likely to be diagnosed if your blood. Phosphate concentration falls below 2.5 milligrams per deciliter (mg/dL) or 0.81 millimoles per liter (mmol/L).

In most cases, your doctor will be able to easily identify the cause of this condition. Problems with nutrition or diseases like diabetes are usually evident.

In some cases, your doctor may also refer you to a urine test to check how much phosphate is being excreted by your urine in 24 hours. If it’s less than 100 mg, you’re not excreting enough. If it’s more than 100 mg, it means your body is not processing the phosphate correctly.

Depending on your symptoms, you may need other testing, such as to check for liver cirrhosis from alcohol misuse.

If a medication caused this condition, you’ll need to stop taking the drug.

You can correct mild symptoms and prevent low phosphate in the future by adding more phosphate to your diet. Milk and other dairy foods are good sources of phosphate.

Or, you can take a phosphate supplement. If your vitamin D levels are low, you’ll also need to increase your intake of this vitamin.

If your hypophosphatemia is severe, you may need to get high doses of phosphate through a vein (IV). People with the familial form will need to take both phosphate and vitamin D supplements to protect their bones. They may also need dental sealants to protect their teeth from decay.

You need phosphate to maintain healthy bones. A lack of it can lead to bone weakness, fractures, and muscle damage. Very severe hypophosphatemia that isn’t treated can affect your breathing and can be life threatening.

Complications of hypophosphatemia include:

What is the main cause of hypophosphatemia?

Acute hypophosphatemia is caused by an imbalance between cells that leads to a short-term decrease in phosphate levels. Chronic hypophosphatemia occurs when the kidneys don’t absorb enough phosphate over time. This can be caused by many conditions and may also be genetic.

How do you fix hypophosphatemia?

To treat hypophosphatemia, you need to treat the underlying cause and replace your phosphate as needed.

Is hypophosphatemia life threatening?

When severe, hypophosphatemia to organ failure and death.

A mild case of hypophosphatemia usually improves if you add more phosphate to your diet or take a supplement. Severe cases will require IV phosphate treatment.

Your outlook depends on whether the condition that caused your low phosphate levels is treated. Once it has been treated, hypophosphatemia shouldn’t return.