Nephrocalcinosis (Nephrocalcinosis)

The article will have two parts:

1. Kidney calcification (Nephrocalcinosis)

2. Renal pyramidal/medullary calcification (Medullary nephrocalcinosis)

PART I: Nephrocalcinosis

Nephrocalcinosis (Nephrocalcinosis)formerly known as “Anderson-Carr kidney or Albright calcinosis”, involves the deposition of calcium salts in the renal parenchyma. Kidney calcification are divided into several categories, with different etiologies based on distribution:

  • Medullary nephrocalcinosis: 95% Cortical nephrocalcinosis: 5%
  • Partial calcification, combined renal cortex and medulla: rare

Note: Renal calcification is related to, but not the same as, kidney stones (nephrolithiasis).
Complications can happen:

  • Acute kidney failure
  • Chronic kidney failure
  • Kidney stones
  • Urinary tract obstruction (acute or chronic, unilateral or bilateral)

Clinical signs
Calcium nodules often break through the papillary epithelium into the pyelonephritis into urolithiasis and, therefore, symptoms may be due to:
Kidney pain
Urinary tract infections
Peeing stones

Macroscopic renal calcification is renal calcification that is visible without magnification, which is detected by radiography, ultrasound, or autopsy.
Macroscopic renal calcification should not be considered synonymous with urolithiasis as it represents metabolic disturbances and has broader complications.
Episodes of urinary tract infections may occur
Polyuria and excessive thirst may be prominent
Hypertension is less common
Microscopic pyuria is always found (Representing chronic inflammatory response to renal medullary calcification)
Distal tubular dysfunction is common with mild salt loss

PART II: Renal pyramidal/medullary calcification (Medullary nephrocalcinosis)

Image features: OLDSmall calcified nodules clustered in each renal pyramid.

Note: It is difficult to diagnose underlying kidney disease based on the morphology of the calcification, except in the following cases: Renal papillary necrosis due to overuse of analgesics because the entire papilla can become calcified, and Spongy kidney disease: is a disease with visible areas of calcification and uneven distribution.


Primary hyperparathyroidism is the most common cause of renal calcification in adults

Distal tubular acidosis is the second most common cause of renal pyramidal calcification

renal medullary spongiform disease, is a common cause of pyramidal calcification, in which calcium is located in the dilated collecting ducts rather than in the renal parenchyma.


A “mnemonic” way of memorizing common used to memorize The cause of renal pyramidal calcification to be: HAM HOP

H: hyperparathyroidism

A: acidosis ((renal tubule)

M: Spongiform renal disease

H: hypercalcemia / hypercalciuria

O: oxalosis

P: renal papillary necrosis

Prognosis: Depends mainly on the cause of the renal pyramidal calcification

The main long-term complication in patients with renal pyramidal calcification is renal failure


Case 1: Reference links:

Upper photo of conventional radiograph of abdomen and lower photo of coronal CT scan of abdomen both show amorphous, coarse calcifications throughout both expenses (white arrows) which corresponds the shape and position of the renal pyramids. The patient had renal tubular acidosis

-> TRANSLATION: The upper image of the unprepared abdominal radiograph and the lower image of the coronary plane abdominal computed tomography both show coarse, amorphous calcifications throughout both kidneys (white arrows) corresponding to their shape. and the position of the renal pyramid. The patient has a renal tubular acidosis.

Case 2: Reference link:

Increased echogenicity of the pyramid and renal calculi in the right kidney (Portuguese: “Rim Direito”).

Ultrasound demonstrates hyperechogenic foci with posterior acoustic shadowing consistently with renal calculus. The pyramids are diffusely echogenicbut without shadowing, suggestive of medullary nephrocalcinosis. Although nephrocalcinosis may eventually progress to involve most of the pyramid, acoustic shadowing is rarely seen even in this situation. Acoustic shadowing may be appreciated only in rare cases of extreme involvement of the pyramids or if there is the development of associated calculi in the adjacent calices, like in this case.

-> TRANSLATION: Increased echogenicity of the renal pyramid and nephrolithiasis in the right kidney (Portuguese: “Rim Direito”).

Ultrasound showed hyperechoic foci with posterior opacities consistent with nephrolithiasis. The renal pyramids have diffuse echo, but no shadow, suggesting renal pyramidal calcification. Although pyramidal calcifications may eventually progress to the extent that most of the pyramids are affected, shadowing is rarely seen even in this setting. Contrast shadow may be seen only in rare cases of multi-pyramidal involvement or if there is an associated associated renal stone development in the adjacent calyx, as in this case.

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Case 3: Reference link:

Dense echogenic shadows are seen mainly at tip of echogenic pyramids.

Case Discussion: The case shows features of nephrocalcinosis (also known as Anderson-Carr kidney).

-> TRANSLATION: Thick echogenic shadows are seen mainly at the apex of the echogenic renal pyramid.

Case Discussion: This case demonstrates features of renal calcification (also known as Anderson-Carr kidney).

Case 4: Reference links:

Medullary nephrocalcinosis. There are cloudlike calcifications seen bilaterally (white arrows), suggestive these calcifcations have formed within a solid organ or tumor. The calcifications conform to the distributionof therenal collecting systems.This is medullary nephrocalcinosis, a condition not synonymous with renal calculi because nephrocalcinosis signifies ametabolic derangement.This patient hadprimary hyperparathyroidism.

-> TRANSLATION: Renal pyramidal calcification. There are cloud-like calcifications seen on either side (white arrows), indicating that these calcifications have formed within a solid organ or tumor. The calcification follows the distribution of renal calyx system. This is pyramidal calcification, a condition that is not synonymous with kidney stones because pyramidal calcification presents metabolic disorder. This patient has primary hyperparathyroidism.

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BS. Vo Thi Thanh Huong

Reference source:

William Herring – Learning Radiology_ Recognizing the Basics-Elsevier (2016)

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