Nephrocalcinosis, once known as Albrights calcinosis after Fuller Albright, is a term originally used to describe deposition of calcium salts in the renal parenchyma due to hyperparathyroidism. The term nephrocalcinosis is used to describe the deposition of both calcium oxalate and calcium phosphate. It may cause acute kidney injury. It is now more commonly used to describe diffuse, fine, renal parenchymal calcification in radiology. It is caused by multiple different conditions and is determined progressive kidney dysfunction. These outlines eventually come together to form a dense mass. During its early stages, nephrocalcinosis is visible on x-ray, and appears as a fine granular mottling over the renal outlines. It is most commonly seen as an incidental finding with medullary sponge kidney on an abdominal x-ray. It may be severe enough to cause (as well as be caused by) renal tubular acidosis or even end stage kidney disease, due to disruption of the kidney tissue by the deposited calcium. Signs and symptoms
Though this condition is usually asymptomatic, if symptoms are present they are usually related to the causative process, (e.g. hypercalcemia). Some of the symptoms that can happen are blood in the urine, fever and chills, nausea and vomiting, severe pain in the belly area, flanks of the back, groin, or testicles. These include renal colic, polyuria and polydipsia:
Renal colic is usually caused by pre-existing nephrolithiasis, as may occur in patients with chronic hypercalciuria. Less commonly, it can result from calcified bodies moving into the calyceal system. Nocturia, polyuria, and polydipsia from reduced urinary concentrating capacity (i.e.
Calcium oxalate and calcium phosphate crystals form when the concentration of the reactants exceeds the limit. The deposits are collected in the inner medullary interstitium in the basement membranes of the thin limbs of the loop of Henle. The calcium phosphate plaques can enlarge into the surrounding interstitial tissue, or even rupture into the tubule lumen and can promote calcium oxalate stone formation. Diagnosis
Nephrocalcinosis is diagnosed for the most part by imaging techniques. The imagings used are ultrasound (US), abdominal plain film and CT imaging. Of the 3 techniques CT and US are the more preferred. Nephrocalcinosis is considered present if at least two radiologists make the diagnosis on US and/or CT. In some cases a renal biopsy is done instead if imaging is not enough to confirm nephrocalcinosis. Once the diagnosis is confirmed additional testing is needed to find the underlying cause because the underlying condition may require treatment for reasons independent of nephrocalcinosis. These additional tests will measure serum, electrolytes, calcium, and phosphate, and the urine pH. If no underlying cause can be found then urine collection should be done for 24 hours and measurements of the excretion of calcium, phosphate, oxalate, citrate, and creatinine are looked at. Stages of nephrocalcinosis
Chemical or Molecular nephrocalcinosis: Defined as a measurable increase in intracellular calcium concentrations, however, it is not visible through X-ray or microscopically. Microscopic nephrocalcinosis: Occurs when depositis are visible by light microscope by obtaining a tissue sample from a biopsy. However, this cannot be seen in an X-ray.