What is hypocalcemia?

Hypocalcemia is a condition in which there is too little calcium in the blood. Calcium is needed by the body to function properly. Calcium can affect nerves, muscles, digestive tract, kidneys and the way the heart functions.

The calcium level in blood is normally controlled by hormones, such as parathyroid hormone (PTH), and vitamin D, which then act on the kidneys, the intestine and bone. When the calcium level becomes too low, symptoms may develop.

Symptoms of hypocalcemia

Symptoms of hypocalcemia depend on the age of the child, how low the serum calcium level is and how quickly hypocalcemia has occurred.

The following are the most common symptoms of hypocalcemia. However, each child may experience symptoms differently. Symptoms may include:

• Irritability
• Muscle twitches
• Jitteriness
• Tremors
• Poor feeding
• Lethargy
• Seizures
• Difficulty breathing
• Difficult walking or using the hands

Hypocalcemia may not be obvious in newborn babies and may only be identified by laboratory tests. The spectrum of clinical features can range from few (if any) if hypocalcemia is mild to life-threatening related to seizures, if more severe. Children are more likely to have symptoms if calcium levels drop suddenly, and symptoms may lessen over time as the body becomes used to hypocalcemia.

What causes hypocalcemia?

Hypocalcemia has many different causes, both acquired and genetic. In infants, hypocalcemia is more common in premature and low birthweight babies because their parathyroid glands are less mature. It may also occur in babies who have a difficult birth or whose mothers have endocrine disorders, such as diabetes or elevated serum levels of calcium.

Hypocalcemia can result from vitamin D deficiency, calcium deficiency, abnormal levels of magnesium in the blood and certain medications. Hypocalcemia can also be caused by inadequate production of PTH levels (hypoparathyroidism), in which case it is accompanied by high levels of phosphorus in the blood. Hypoparathyroidism can occur by itself or can be part of a complex syndrome. Hypocalcemia can also occur in children with kidney problems.

Genetic causes of hypocalcemia can be related to different abnormalities in vitamin D metabolism, PTH production or action, and how the body senses calcium.

How is hypocalcemia diagnosed?

The diagnosis of hypocalcemia is based on demonstration of a low serum level of calcium using a blood test. Discovery of the underlying cause of hypocalcemia will require a comprehensive laboratory evaluation of levels of calcium, phosphorus, magnesium, PTH and vitamin D metabolites in the blood and levels of calcium in the urine.

Hypoparathyroidism is diagnosed when inappropriately low PTH levels are present with low calcium levels and high phosphorus levels. X-rays may be done to evaluate for bone disease. Your child may have an ultrasound of the kidneys to evaluate them for structural defects or damage or for calcium deposits. Genetic testing may also be done.

Treatment for hypocalcemia

The treatment of hypocalcemia depends on the severity and cause of the hypocalcemia. In mild cases, hypocalcemia may not require treatment, and it may go away on its own. Most patients require treatment with calcium and/or vitamin D, given by mouth.

For more severe presentations, intravenous (IV) calcium may need to be given to increase calcium levels and patients will require hospitalization. Your child will have frequent blood draws to check the level of calcium.

Outlook for children with hypocalcemia

The long-term treatment of hypocalcemia is based on the specific underlying cause.