Genitourinary Radiology > Kidneys > Parenchymal > Small Kidney > Analgesic Nephropathy

Analgesic Nephropathy

Analgesic nephropathy is the result of chronic ingestion of large doses of NSAIDS, such as phenacetin, aspirin, or acetaminophen.

Findings include small, irregular kidneys; diffuse paillary necrosis; and medullary nephrocalcinosis (calcification of sloughed papilla).

Contast enhanced CT scan of both kidneys in excretory phase shows diffuse and bilaterally papillary necrosis. This is seen as small collections of contrast in the medullary pyramids (where no contrast should be because there should be normal medullary pyramid tissue) (arrows). However, with papillary necrosis, portions of the papilla slough into the collecting systemand the space is demonstrated on excretory images as tiny collections of contrast where none should be. This appearance is known as "golf ball on a tee". See illustration.

Diagram of normal (left) and abnormal (right) papilla.  On the left, a normal renal medulla sits in its respective calyx.  In the medullary pyramid with papillary necrosis, the is a portion of the medulla which has sloughed due to necrosis.  The absent tissue leaves a hole in the medullary that is filled with contrast on delayed contrast enhanced images.  This gives the so-called "golf ball on a tee" configuration.

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