What is Hyperphosphatemia

Hyperphosphatemia is the condition of having too much phosphate in your blood. Phosphate forms when a mineral called phosphorus binds with oxygen. Phosphate is important because it binds with calcium to form and support your teeth and bones.

However, if too much phosphate builds up in your blood, it binds to calcium in your blood and causes low calcium levels (hypocalcemia). Too much phosphate binding to calcium can also cause stones (calcifications) to build up in your body. This can damage your kidneys, heart, and blood vessels.

What are the causes?

The most common cause of this condition is kidney failure. A diseased kidney may not filter enough phosphate out of your blood. Other causes of hyperphosphatemia include:

• Taking in too much phosphate. This can happen from taking too many laxatives or using enemas that contain phosphate. It can also result from receiving too much phosphate in IV fluids.
• Increased absorption of phosphate. This can happen if you take too much vitamin D. Vitamin D causes more phosphate to be absorbed in the digestive tract.
• Conditions that release phosphate from inside the cells of the body (redistribution). This can happen from:
  • Severe muscle injury, such as a crushing injury, or any condition that causes muscle cells to break down quickly.
  • Cancer cells that die quickly.
  • Severe infection.
  • Poorly controlled diabetes.
• Low parathyroid hormone. This hormone stimulates excretion of phosphate in the kidney. If it gets too low, phosphate can start to build up in the blood.

What are the signs or symptoms?

In most cases, there are no symptoms of this condition. Symptoms can develop if the condition leads to hypocalcemia or calcifications, or if it occurs along with kidney failure.

• Signs of hypocalcemia include:
  • Muscle cramps or spasms.
  • Numbness and tingling around the mouth.
  • Abnormal heart rhythms.
  • Seizures.
• Signs of calcifications include:
  • Hard bumps (nodules) under the skin. The nodules may cause an itchy skin rash.
  • Joint pain.
• Signs and symptoms of kidney failure include:
  • Fatigue.
  • Shortness of breath.
  • Appetite loss.
  • Nausea and vomiting.

How is this diagnosed?

This condition may be diagnosed based on a blood test to check whether you have a high level of phosphate. Your health care provider may suspect this condition based on your symptoms and medical history, especially if you have kidney disease or another condition that can cause hyperphosphatemia. The condition is sometimes found during a routine blood test.

You may also have other tests, including:

• Blood tests for calcium, parathyroid hormone, and kidney function.
• Urine tests for phosphate.
• Imaging studies to look for calcifications in skin, blood vessels, kidneys, or the heart.
• A test to check for physical signs of hypocalcemia. These include increased reflexes and abnormal facial muscle contractions when tapping on the face (Chvostek’s sign).

How is this treated?

Hyperphosphatemia can be reversed if the underlying condition is found and treated. If there is no kidney failure, the condition may improve without treatment. If there are symptoms of kidney failure, treatment may include:

• IV fluids and medicines that increase urine flow (diuretics) to flush out the phosphate.
• Filtering phosphate out of the blood with a procedure called dialysis.
• Medicines that bind to phosphate to pull it out of the blood.
• Limiting phosphorus or phosphate in the diet.

Follow these instructions at home:

• Take over-the-counter and prescription medicines only as told by your health care provider.
• Follow instructions from your health care provider about eating or drinking restrictions.
• Check food labels for phosphate or phosphorus.
• You may need to work with a dietitian to lower the amount of phosphorus in your diet.
  • Foods that are low in phosphorus include fruits, vegetables, fresh or frozen meat, white rice, and white bread.
  • Foods that are high in phosphorus include beer, chocolate, milk, cheese, liver, and oysters. Phosphorus is also used as a food additive and in many bottled beverages.
• Drink enough fluid to keep your urine pale yellow.
• Do not take vitamin D or phosphorus supplements.
• Do not take laxatives or use enemas that contain phosphorus or phosphate.

Contact a health care provider if:

• You have signs of hypocalcemia.
• You have itchy bumps under your skin.
• You have joint pain.
• You have signs or symptoms of kidney failure.

Get help right away if:

• You have a seizure.
• You have chest pain.
• You have difficulty breathing.

Summary

• Hyperphosphatemia is the condition of having too much phosphate in your blood.
• Kidney failure is the most common cause of this condition.
• Most people do not have signs or symptoms of hyperphosphatemia unless it leads to another condition.
• Hyperphosphatemia can lead to hypocalcemia and calcifications in the body.
• Treatment for hyperphosphatemia may include IV fluids, filtering the blood with dialysis, medicine to bind phosphate, and limiting phosphorus in your diet.