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What Is Hypocalcemia?

Medically Reviewed by Dan Brennan, MD on June 21, 2021

Hypocalcemia is when you have too little calcium in your blood. Calcium is essential for your body to function normally. Your hormones control your blood calcium levels.

It can be challenging to know if you have hypocalcemia, as usually it is only discovered through medical tests. Nonetheless, it is essential to treat due to the health problems it can cause.

Hypocalcemia can be caused by certain genetic factors, or due to other deficiencies or conditions.

Causes of Hypocalcemia

Usually, hypocalcemia happens when large amounts of calcium are put out when you urinate, or too little calcium enters your blood from your bones. This could be caused by certain genetic factors, vitamin deficiencies, or other conditions.

Some of the reasons either these things can happen include:

  • Hypoparathyroidism. The parathyroids are located near the thyroid gland in the back of the neck. The parathyroids make a hormone called parathyroid hormone ( PTH), which regulates the amount of calcium in your body. Hypocalcemia is when you make lower levels of PTH than you need, which causes you to also make less calcium. 
  • Pseudohypoparathyroidism. This is a genetic disorder where your body cannot react to PTH. This disorder causes you to make too little calcium, which sends your body into hypocalcemia.
  • Being born without parathyroid glands. Some people are simply born without parathyroid glands. A condition like DiGeorge syndrome — which is when you are missing a part of chromosome 22 — can also cause you to have smaller than normal parathyroid glands.
  • Hypomagnesemia. This is when you have an abnormally low level of magnesium in the blood. Lower amounts of magnesium in your body reduce the abilities of the PTH.
  • Vitamin D Deficiency. Vitamin D is a steroid that helps to maintain normal calcium levels. Lower amounts of vitamin D make your body’s calcium absorption levels drop. This usually happens if you are malnourished or do have enough sun exposure in your life.
  • Kidney issues. Having any sort of renal failure or kidney disease constantly drains the levels of calcium in your blood.
  • Calcium deficiency. If you do not consume enough calcium or have disorders that interfere with your body’s ability to absorb calcium, this can cause hypocalcemia. 
  • Pancreatitis. This condition refers to when your pancreas becomes inflamed. New research has found that often, the body’s protective responses to pancreatitis cause hypocalcemia. 
  • Certain medications. Drugs like rifampin (an antibiotic), and phenytoin and phenobarbital (anti-seizure drugs) can cause this. Additionally, medicines that fight bone cancers and other bone issues are also linked with hypocalcemia. These drugs include alendronate, ibandronate, risedronate, and zoledronic acid. 

Symptoms

Some of the symptoms of hypocalcemia include: 

  • Twitching in your hands, face, and feet
  • Numbness
  • Tingling 
  • Depression 
  • Memory loss 
  • Scaly skin
  • Changes in the nails 
  • Rough hair texture
  • Cramps
  • Seizures
  • Abnormal heartbeats

Often, by simply treating hypocalcemia, these symptoms will immediately go away. However, hypocalcemia is usually caused by another condition, so you might experience additional symptoms. In that case, you will need to treat the first condition to treat your hypocalcemia.

Testing

The way to find out whether or not you have hypocalcemia is by taking a blood test. This test will be able to find out whether or not you have hypocalcemia. It can also help tell you whether or not it is caused by your kidneys or parathyroid.

If your blood test comes with a blood calcium level of fewer than 8.8 milligrams per decilitre (Mg/dL), that means that you have hypocalcemia. Sometimes you might need further testing to fully understand what is causing your hypocalcemia. 

Some of the additional tests could be an ultrasound of your kidneys or genetic testing. An ultrasound is when high-frequency sound waves make a picture of the inside of your body. This allows a doctor to see your organs and other body systems to see any possible problems or abnormalities. However, many different conditions can cause hypocalcemia, so it depends on your unique medical situation. 

Treatment

If you simply just have hypocalcemia, usually vitamin C or vitamin D supplementation is all you need to treat it and take away any symptoms. Usually, if symptoms of hypocalcemia spontaneously happen, your provider will give you intravenous (IV) supplementation. 

If your hypercalcemia is due to hyperparathyroidism, your provider might give you a synthetic version of HTP. 

After getting diagnosed with hypocalcemia, you will need to get regular testing after being treated. This will ensure your safety and make sure that your blood calcium levels do not get too low ever again. This is especially true for children. 

WebMD Medical Reference

Sources

SOURCES: 

Children’s Hospital of Philadelphia: “Hypocalcemia.”

Current rheumatology reports: “Vitamin D: more than just affecting calcium and bone.”

Johns Hopkins Medicine: “Hypoparathyroidism.”

Indian Journal of Critical Care Medicine: “Hypocalcemia in acute pancreatitis revisited.”

Mayo Clinic: "DiGeorge syndrome (22q11.2 deletion syndrome)," “Hypoparathyroidism,” "Ultrasound."

Merck Manual Consumer Version: “Hypocalcemia (Low Level of Calcium in the Blood).”

National Center for Advancing Translational Sciences: “Pseudohypoparathyroidism.”

UCLA Health: “Disorders of Calcium Balance.”

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