A kidney disorder involving deposition of calcium and oxalate or phosphate in the renal tubules and interstitium (the areas between the tubules); this may result in reduced kidney function.

Causes, incidence, and risk factors

Nephrocalcinosis is caused by a number of conditions. These include:

excess excretion of calcium by the kidney

renal tubular acidosis

medullary sponge kidney

hypercalcemia

(high calcium levels in the blood)

renal

cortical

necrosis

tuberculosis

Fragments of calcium oxalate or

calcium phosphate may break free from the kidney and provide nuclei for formation of stones ( nephrolithiasis ). This may result in obstructive uropathy , possibly leading to eventual kidney failure if the obstructing stones are not passed in the urine or removed. Nephrocalcinosis may therefore be discovered when symptoms of renal insufficiency / renal failure , obstructive uropathy, or urinary tract stones develop. Nephrocalcinosis is relatively common in premature infants, partly from intrinsic kidney calcium losses and partly from enhanced calcium excretion when they are given loop diuretics.

Signs and tests

An examination is nonspecific for nephrocalcinosis but may indicate disorders that occur as a consequence of nephrocalcinosis. There may be signs of fluid overload, such as abnormal heart and lung sounds, if kidney function is poor.

An

abdominal film shows renal calcification.

An

abdominal CT scan shows nephrocalcinosis.

Other tests may be performed to diagnose and determine the extent of associated disorders.

Treatment

The goal of treatment is reduction of symptoms. The cause of the disorder must be treated. If the cause is type 1 renal tubular acidosis , Vitamin D , and calcium in diet should not be given to correct bone disorders associated with the condition because this will worsen nephrocalcinosis. Medications that enhance calcium excretion should be discontinued (CONSULT YOUR HEALTH CARE PROVIDER FIRST!) Conditions that result from the disorder should be treated in their usual manner.

Expectations (prognosis)

The outcome varies depending on the extent of complications and the cause of the disorder.

Complications

acute renal failure

chronic renal failure

kidney stones

obstructive uropathy

(

acute or chronic , unilateral or bilateral)

Calling your health care provider

Call your health care provider if symptoms indicate that disorders associated with nephrocalcinosis may be present. Emergency symptoms include suddenly decreased urine output , and decreased consciousness related to calcium levels and/or kidney failure.

Prevention

Prompt treatment of causative disorders, including renal tubular acidosis , may help prevent nephrocalcinosis.