Medullary types:
central erosion of the papilla
ball-on-tee appearance
Papillary types:
lobster claw appearance
signet ring appearance
Calyceal blunting after papillary sloughing and epithelialisation
Case Discussion
Renal papillary necrosis is defined as coagulative necrosis of the renal papilla. The renal medulla and papilla are susceptible to ischaemic necrosis due to their blood supply and hypertonic environment.
Causes of renal papillary necrosis include diabetes mellitus, abuse of analgesics, non-steroidal anti-inflammatory drugs (NSAIDs), sickle cell anaemia, pyelonephritis, renal vein thrombosis, tuberculosis, and obstructive uropathy.