What are the other Names for this Condition? (Also known as/Synonyms)

• Hypercalcemic Nephropathy

What is Nephrocalcinosis? (Definition/Background Information)

• Nephrocalcinosis is a disorder that occurs when too much calcium is deposited in the kidneys
• It commonly occurs in premature infants. Individuals may not have symptoms or may have symptoms related to the condition causing Nephrocalcinosis
• If kidney stones are present, symptoms may include blood in the urine, fever and chills, nausea and vomiting, and severe pain in the belly area, sides of the back (flank), groin, or testicles
• Later symptoms may be associated with chronic kidney failure. It may be caused by use of certain medications or supplements, infection, or any condition that leads to high levels of calcium in the blood or urine including hyperparathyroidism, renal tubular acidosis, Alport syndrome, Bartter syndrome, and a variety of other conditions
• Some of the underlying disorders that can cause Nephrocalcinosis are genetic, with the inheritance pattern depending on the specific disorder
• Treatment differs depending on the cause of Nephrocalcinosis and often aims to prevent more calcium from being deposited in the kidneys

(Source: Nephrocalcinosis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Nephrocalcinosis? (Age and Sex Distribution)

• Nephrocalcinosis is a rare, congenital disorder. The presentation of symptoms may occur at birth
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Nephrocalcinosis? (Predisposing Factors)

The risk factors for Nephrocalcinosis may include:

• Premature birth
• Presence of kidney stones
• Chronic kidney failure
• Sarcoidosis
• Infections
• Overuse of vitamin D supplements
• Osteoporosis
• Certain inherited conditions (such as multiple endocrine neoplasm type 1 and Bartter syndrome)

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Nephrocalcinosis? (Etiology)

Nephrocalcinosis may be caused by underlying disorders or conditions, medications or supplements, and infections. The causes may include:

• Primary hyperparathyroidism 
• Distal renal tubular acidosis (RTA)
• Hypervitaminosis-D (increased levels of vitamin D)
• Sarcoidosis 
• Phosphate supplementation
• Medullary sponge kidney
• Osteoporosis due to immobilization, menopause, aging, or steroids
• Primary (familial) hyperoxaluria, or secondary hyperoxaluria
• Chronic disorders such as Bartter syndrome, primary hyperaldosteronism, Liddle syndrome, and 11-beta hydroxylase deficiency
• Autosomal dominant hypophosphatemic rickets and X-linked hypophosphatemic conditions
• Premature birth 
• Use of certain medications such as acetazolamide
• Tuberculosis of the kidney
• Infections related to AIDS

Nephrocalcinosis itself is not inherited. However, the condition causing Nephrocalcinosis in an individual may be inherited. Some inherited conditions that may be associated with Nephrocalcinosis include:

• Multiple endocrine neoplasia type 1 (MEN1)
• Familial distal renal tubular acidosis
• Chronic granulomatous disease
• Primary hyperoxaluria
• Bartter syndrome
• Alport syndrome
• Primary hyperaldosteronism
• Liddle syndrome
• 11-beta hydroxylase deficiency
• Autosomal dominant hypophosphatemic rickets and X-linked hypophosphatemic conditions
• Williams syndrome 
• Beta thalassemia

(Source: Nephrocalcinosis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

What are the Signs and Symptoms of Nephrocalcinosis?

The signs and symptoms of Nephrocalcinosis may not be apparent during the early stages of the disorder. At this stage, the symptoms may pertain the pre-existing condition that caused Nephrocalcinosis.

People who also have kidney stones may have:

• Blood in the urine
• Fever and chills
• Nausea and vomiting
• Severe pain in the belly area, sides of the back (flank), groin, or testicles

(Source: Nephrocalcinosis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is Nephrocalcinosis Diagnosed?

Nephrocalcinosis is diagnosed on the basis of the following information:

• Complete physical examination
• Thorough medical history evaluation
• Assessment of signs and symptoms. These symptoms may include renal insufficiency and stones in the urinary tract
• Laboratory tests, including
  • Blood test for calcium, uric acid and parathyroid hormone levels, among others
  • Analysis of urine, to check for red blood cells and crystals
  • 24 hour urine collection test to check for levels of calcium and sodium, among others
• Imaging studies
  • Abdominal CT scan
  • Ultrasound of the kidney
• Biopsy studies, if necessary

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Nephrocalcinosis?

The complications of Nephrocalcinosis may include:

• Acute kidney failure
• Long-term (chronic) kidney failure
• Obstructive uropathy (acute or chronic, unilateral or bilateral)

How is Nephrocalcinosis Treated?

The treatment for Nephrocalcinosis aims to address the signs and symptoms of the disorder, as well as decrease the amount of calcium deposits in the kidneys. Treatment methods may include:

• Treatment of an underlying condition (if known) causing Nephrocalcinosis
• Hydration with normal saline to reverse elevated levels of calcium in blood
• Thiazide diuretics may be prescribed, if calcium deposit is visible in kidney tissue without magnification
• Restricting salt in the diet
• Potassium and magnesium supplementation
• Discontinuing any medication that may lead to calcium loss

How can Nephrocalcinosis be Prevented?

Nephrocalcinosis may be prevented by seeking treatment for pre-existing disorders that may cause the condition.

• In addition, an early diagnosis and prompt treatment may reverse calcium deposits in the kidney and prevent kidney damage
• Keeping oneself hydrated by drinking plenty of fluids may also help decrease stone formation in the urinary tract
• Active research is currently being performed to explore the possibilities for treatment and prevention of disorders such as Nephrocalcinosis
• Regular medical screening at periodic intervals with tests and physical examinations are recommended

What is the Prognosis of Nephrocalcinosis? (Outcomes/Resolutions)

• The prognosis of Nephrocalcinosis is dependent upon the severity of the signs and symptoms and associated complications, if any
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications
• With an early diagnosis and prompt treatment, it may be possible to prevent calcium deposits in the kidney. However, it may not be possible to remove the existing kidney deposits
• The prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Nephrocalcinosis:

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/