Image Quiz

This is an abdominal CT. What's the diagnosis? (Hint - focus on the white arrows).

 Source: Dr. J.G.Smirniotopoulos, continuingeducation@usuhs.mil

The answer to the image quiz from 1/21/12 is medullary nephrocalcinosis. This ultrasound image shows increased echogenicity of the renal medulla (the pyramids are normally hypoechoic to cortex). 

Medullary nephrocalcinosis has many causes. The most common causes are hyperparathyroidism, renal tubular acidosis, and medullary sponge kidney. Rarer causes of medullary nephrocalcinosis are papillary necrosis, hypercalcaemia, hypercalciuria, prematurity, and primary hyperoxaluria.

This patient had nephrocalcinosis due to Bartter’s Syndrome, a hereditary disorder of ion transporters.

What is the radiological abnormality and what is the differential diagnosis?

Source: Dr Laughlin Dawes. In Chapman S, Nakielny R. Eds., Aids to Radiological Differential Diagnosis. 4th edition. Saunders 2003