What is deposited in the kidney and where?
The deposits consist of calcium salts - phosphate or oxalate. By location, medullary nephrocalcinosis is distinguished, when calcium accumulates in the pyramids of the medulla, and the rarer cortical nephrocalcinosis, affecting the cortex. The medullary form is more common and is usually associated with metabolic disorders. Cortical is the result of severe inflammation or necrosis of the cortex. Deposits damage the tubules, causing the kidney to be less able to concentrate urine and maintain acid-base balance.
- Medullary - in pyramids, the most common option
- Cortical - in the cortex, after severe lesions
- Chemically most often calcium phosphate or oxalate
- Often associated with kidney stones
- The degree of severity is assessed by ultrasound and CT
Causes and risk factors
The most common group of causes are conditions with elevated levels of calcium in the blood and urine. These are primary hyperparathyroidism, excessive intake of vitamin D and calcium supplements, sarcoidosis, some tumors, prolonged immobility. The second group is renal tubular disorders, primarily distal renal tubular acidosis, in which the urine becomes insufficiently acidic. Separately, there are hereditary metabolic diseases, primary hyperoxaluria and the consequences of using certain drugs. In premature infants, nephrocalcinosis can occur during intensive care.
- Primary hyperparathyroidism
- Overdose of vitamin D and calcium supplements
- Distal renal tubular acidosis
- Sarcoidosis and other granulomatous diseases
- Primary hyperoxaluria and hereditary tubulopathies
- Prolonged immobilization, some diuretics and drugs
- Sponge bud
Symptoms
Nephrocalcinosis itself is painless, and complaints are usually related to either the underlying disease or complications. With high blood calcium, you may experience weakness, thirst, nausea, constipation, and bone pain. Tubular acidosis causes muscle weakness and growth retardation in children. If stones form in parallel, renal colic occurs. Over a long period of time, the ability to concentrate urine decreases: a person drinks a lot and urinates frequently, including at night.
- Most often - no complaints
- Thirst and excessive urination
- Weakness, nausea, constipation with high calcium
- Bone pain and muscle weakness
- Renal colic with stones
- Recurrent urinary tract infections
Survey
The deposits are clearly visible on ultrasound as increased brightness of the pyramids, and computed tomography without contrast clarifies the extent and at the same time identifies stones. Then the main part begins - the exchange examination. Blood calcium and phosphorus, parathyroid hormone, vitamin D, acid-base levels, as well as daily excretion of calcium, oxalates and citrate in the urine are determined. If hereditary forms are suspected, the examination is continued in a specialized center.
- Kidney ultrasound
- MSCT of the kidneys without contrast
- Total and ionized calcium, phosphorus
- Parathyroid hormone and vitamin D
- General urine analysis and urine pH
- Daily excretion of calcium and oxalates
- Creatinine and GFR calculation
Treatment and prevention
Already formed deposits, as a rule, do not resolve, so treatment is aimed at eliminating the cause and preventing new ones. In case of hyperparathyroidism, surgery on the parathyroid glands may be required; in case of tubular acidosis, citrate and bicarbonate preparations are prescribed; in case of excess vitamin D, it is discontinued. A universal measure for everyone is sufficient drinking regimen to dilute the urine. The diet is adjusted based on test results: you cannot thoughtlessly exclude calcium from the diet, this can increase the excretion of oxalates.
- Treatment of the underlying disease
- Stopping excess doses of vitamin D and calcium
- Citrate preparations for tubular acidosis as prescribed by a doctor
- Adequate fluid intake throughout the day
- Limiting salt and high-oxalate foods when indicated
- Monitoring ultrasound and analyzes over time
- Do not take dietary supplements with calcium and vitamin D without analysis