What is Hypercalciuria?

Hypercalciuria is a common disorder among children. The term means excess calcium in the urine. It may be secondary—that is, a side-effect of some other condition causing high levels of calcium in the bloodstream and/or urine—or it may be “idiopathic”—occurring on its own, with normal blood calcium levels.

Idiopathic Hypercalciuria is a common disorder seen in 3 to 6 percent of children. While it may occur at any age, even in newborns, it most often comes to light in children between 4 and 8 years old. Sometimes, it runs in families.

Excess calcium in the urinary tract causes problems because it tends to form salts that crystallize, causing pain or other urinary symptoms, depending upon the size and location of the crystals. Large ones are known as kidney stones.

Causes / Risk Factors Show

The digestive system, bones, kidneys and hormones (endocrine system) can all affect calcium levels in the urine, so there are many possible causes. In many cases, the direct cause is unknown.

Risk factors for Hypercalciuria include:

Family history of kidney stones
Diet high in sodium and protein
Taking medications such as furosemide (Lasix), corticosteroids, excessive vitamin D and methylxanthines, such as theophylline

Associated Conditions Show

Conditions that are commonly associated with Hypercalciuria include:

Genetic conditions such as Bartter syndrome, medullary sponge kidney (Cacchi–Ricci disease) and Dent disease
Immobilization, as with spinal cord injuries
Disorders of bone mineralization; osteoporosis
Hypervitaminosis D
Obesity
Anorexia/bulimia
Hypertension
Certain cancers, such as leukemia
Hypercalcemia (elevated blood calcium levels)
Hyperthyroidism, as from Graves disease
Hyperparathyroidism
Sarcoidosis

Signs and Symptoms of Hypercalciuria Show

Children with any of the following may have Hypercalciuria:

Blood in urine, either visible or microscopic
Urinary symptoms such as pain with urination, needing to go urgently or frequently, or bedwetting
Side, belly, or lower belly pain
Kidney stones
Repeated urinary tract infections (UTI)
Irritability (infants)

These signs and symptoms may occur at any age, but are often first seen in 4- to 8-year-olds.

How is Hypercalciuria Diagnosed? Show

Hypercalciuria can occur at any age and is mainly diagnosed by measuring calcium in the urine. The following tests may be performed:

24 hour urine test for calcium and other minerals (if the child’s age makes this impossible, a single urine sample will be tested)
Blood tests to rule out specific diseases that may be causing the hypercalciuria
Imaging studies, especially renal ultrasound which does not deliver any radiation (we are part of Image Gently, an alliance geared toward reducing children’s radiation exposure), to look for kidney abnormalities or stones

How is Hypercalciuria Treated? Show

Our treatment for hypercalciuria includes:

Addressing any secondary disease causing the hypercalciuria
Dietary modifications to increase fluid intake and lower sodium intake, with the help of a dietary specialist (however, to promote healthy bones and growth, we do not generally recommend restricting dietary calcium or protein)
If diet changes aren’t enough, medications to decrease calcium in the urine or prevent stone formation may be added
Periodically repeating 24 hour urine tests to check how well treatment is working

Prognosis / Long-term Outlook Show

Most often, with dietary modifications—and medication if needed—urine calcium can be lowered to the normal range, lowering the risk of kidney stones. Because idiopathic hypercalciuria is a congenital (existing from birth) tendency, these children will always need to be careful about their diets to diminish the risk of developing kidney stones and other associated problems.