Nephrocalcinosis is a kidney disorder in which there is an increased amount of calcium in the kidneys.

Nephrocalcinosis may be caused by a number of conditions:

• Excess excretion of calcium by the kidney
• Renal tubular acidosis
• Medullary sponge kidney
• Hypercalcemia (high calcium levels in the blood)
• Renal cortical necrosis
• Tuberculosis

Pieces of of calcium oxalate or calcium phosphate may break free from the kidney. The pieces (deposits) enter the kidney tubules and areas in between them. The deposits may result in reduced kidney function. Pieces of calcium may lead to the formation of stones (nephrolithiasis).

This condition is relatively common in premature infants, partly from intrinsic kidney calcium losses and partly from enhanced calcium excretion when they are given loop diuretics.

There are generally no early symptoms. Later symptoms related to nephrocalcinosis and associated disorders may include:

• Blood in the urine
• Blood in the vomit or stools
• Changes in mental status
  • Drowsy, lethargic, hard to arouse
  • Delirium or confusion
  • Coma
• Decrease in the force of the urinary stream, stream small and weak
• Decrease in sensation, especially the hands or feet
• Easy bruising or bleeding
• Feeling of incomplete emptying of the bladder
• Flank pain or back pain
• Generalized swelling and fluid retention
• Increased urine volume or urine output, decreased
• Increased urinary frequency or urgency
• Nausea, vomiting
• Need to urinate at night (nocturia)
• Painful urination (burning or stinging with urination)
• Seizures
• Urinary hesitancy (difficulty initiating the flow of urine)
• Urinary incontinence

An examination may indicate disorders that occur as a consequence of nephrocalcinosis. For example, it may be discovered when symptoms of renal insufficiency, kidney failure, obstructive uropathy, or urinary tract stones develop.

There may be signs of fluid overload, such as abnormal heart and lung sounds, if kidney function is poor.

Imaging tests can help diagnose this condition. Tests that may be done include:

• Abdominal CT scan
• Abdominal film

Other tests may be done to diagnose and determine the severity of associated disorders.