What is hypercalcemia?

Hypercalcemia refers to an abnormally high concentration of calcium in the blood. Calcium circulates through the bloodstream and is needed by the body for bone health and many other processes. Proper levels of calcium ensure optimum function of your nerves, muscles, digestive tract, kidneys and even your heart.

The calcium level in blood is normally controlled by vitamin D and hormones, such as parathyroid hormone (PTH), which act on the kidneys, the intestine and bone. Circulating concentrations of calcium are greater in children than in adults, and the diagnosis of hypercalcemia in younger patients requires the use of age-appropriate normal ranges. Hypercalcemia occurs less commonly in children than adults.

Symptoms of hypercalcemia

Whether someone with hypercalcemia will have symptoms is dependent upon the degree of hypercalcemia, the duration of the hypercalcemia and the age of the child.

Some of the most common symptoms include:

• Kidney pain (due to kidney stones)
• Bone pain
• Aches and pains
• Abdominal pain
• Nausea and vomiting
• Poor appetite
• Constipation
• Chronic fatigue/tiredness
• Excessive sleepiness
• Frequent urination
• Increased thirst
• Confusion
• Muscle weakness

When the serum calcium concentration is only slightly elevated, infants and children may not have symptoms or may have nonspecific symptoms, such as mild fatigue or constipation. For more severe cases, children may become very weak and irritable, may have nausea and loss of appetite, and may experience poor weight gain, but each child may experience symptoms differently.

Causes of hypercalcemia

Hypercalcemia has many different causes, both acquired and genetic. Acquired causes for hypercalcemia can be due to excessive vitamin D and calcium intake, low phosphorus levels, certain medications, the ketogenic diet, certain infections, and reduced activity (immobilization). Hypercalcemia can occur in very young infants due to excessive vitamin D action that occurs as a result of injury to skin or fat tissue or from genetic conditions. Hypercalcemia can also accompany other medical conditions, such as cancer. Genetic causes of hypercalcemia can be related to different abnormalities in vitamin D metabolism, PTH levels and how the body senses calcium.

Diagnosis of hypercalcemia

The diagnosis of hypercalcemia requires a simple blood test for measurement of the serum calcium level. In order to determine the cause of hypercalcemia, a child will need additional laboratory tests, including measurement of serum levels of phosphorus, PTH and vitamin D metabolites. In addition, evaluation of the urine is performed to measure calcium levels.

Hypercalcemia with increased PTH suggests a parathyroid cause, such as primary hyperparathyroidism. If this is suspected, imaging of the parathyroid glands may be done. Your child may also have skeletal X-rays and bone densitometry (DXA scan) to look for bone thinning and erosions that are sometimes associated with hyperparathyroidism. A kidney ultrasound can identify calcium deposits in the kidneys. Genetic testing may also be performed depending on the cause of hypercalcemia.