Bilateral cortical nephrocalcinosis

• bilateral diffuse punctateThin rims of dystrophic calcification seen at the outer margins of the renal cortex with no evidence(tramline), which extend into the medullary spaces along the column of medullary calcificationBertin on the left side.
• no CT evidence of urolithiasis or back-pressure changes. 
• the revised bone window revealed no evidence of hyperparathyroidismclearly illustrates the calcifications. 

• the above described features are suggestive of bilateral cortical nephrocalcinosiswith the typical appearance of thin rims of dystrophic calcification which may be deposited at the inner and outer margins of the renal cortex as a result of a major vascular insult that produces cortical necrosis, or rarely, as a consequence of glomerulonephritis, hyperoxaluria, and Alport syndrome, with the development of cortical nephrocalcinosis.
• renal calcification can be found in the collecting system and is termed nephrolithiasis
• whenThe pattern of parenchymal calcification is found in the renal parenchyma itself, the term nephrocalcinosis is used
• nephrocalcinosis can be subdivided into medullary and cortical types
• cortical nephrocalcinosis is 20 times rarer than medullary nephrocalcinosis 
• three patterns of cortical calcifications have been described:
  • thin peripheral band of calcifications (most common)
  • said to resemble a tramline or railroadtracks or less likely two thin parallel calcified tracks
  • or multiple punctatepunctuate calcifications in a random distribution (least common)
  .

• there is ​no correlation between the pattern of calcification and a specific cause

• causes of cortical nephrocalcinosis can be remembered by the mnemonic:

​COAG

• C: corticalcortical necrosis

• O: oxalosis

• A: Alport syndrome

• G: (chronic) glomerulonephritis