# Renal Papillary Necrosis and Analgesic Nephropathy > Renal papillary necrosis and analgesic nephropathy for NEET-PG Medicine, with NSAID and diabetic causes, the ring sign and haematuria with sloughed papillae. - Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/renal-papillary-necrosis-and-analgesic-nephropathy - Exam / course: NEET-PG · Subject: Medicine - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-14 - Last updated: 2026-10-14 - Reference basis: Harrison's Principles of Internal Medicine; Brenner and Rector's The Kidney - How to cite: "Renal Papillary Necrosis and Analgesic Nephropathy", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/renal-papillary-necrosis-and-analgesic-nephropathy ## Direct answer Renal papillary necrosis is ischaemic necrosis of the renal papillae, the tips of the medullary pyramids, and analgesic nephropathy is its most important drug-related form. Diabetes mellitus, sickle cell disease and urinary tract obstruction are the other classic causes. Gross haematuria with loin pain is the usual presentation, and a ring-shaped papillary shadow on urography or CT supports the diagnosis. ## What you must remember - **Definition:** ischaemic necrosis of one or more renal papillae, which may slough into the urine and cause obstruction. - **Analgesic nephropathy:** chronic interstitial nephritis with papillary necrosis, most often from long-term combination analgesics containing NSAIDs, with risk tracking cumulative dose. - **Diabetes and sickle cell disease:** the two non-analgesic causes most often named in exams, both compromising medullary perfusion and oxygenation. - **Obstruction and infection:** urinary obstruction and acute pyelonephritis, especially in diabetics, add ischaemic and infective injury to the papillae. - **Ring sign:** a ring-shaped contrast outline around a necrotic papilla on excretory urography or CT, the classic radiological clue. - **Sloughed papillae:** necrotic papillary fragments in the urine can cause renal colic when they block the ureter and are a diagnostic clue in haematuria. - **Analgesic nephropathy triad:** papillary necrosis, chronic interstitial nephritis and urothelial tumours of the renal pelvis, ureter or bladder. ## A step-by-step approach from suspicion to diagnosis Papillary necrosis is easy to miss without a focused history. The steps below follow a patient presenting with haematuria or loin pain. 1. **Take a precise drug history.** Ask about years of daily analgesic use, including over-the-counter combinations and NSAIDs, because risk tracks cumulative dose. Also ask about diabetes control, sickle cell disease and obstruction from stones or prostatic enlargement. 2. **Recognise the clinical picture.** Loin pain, gross haematuria, sometimes with clots, and sterile pyuria are typical. Renal colic may occur when sloughed papillae block the ureter. 3. **Confirm on imaging.** Excretory urography or CT is the key test and can show a ring-shaped shadow around a necrotic papilla, along with calyceal clubbing or cavitation. Ultrasound is less sensitive and may miss early disease. 4. **Exclude mimics.** Renal tuberculosis also causes papillary necrosis with sterile pyuria, so urine acid-fast bacilli culture or PCR should be sent when suspicion persists. 5. **Screen for urothelial tumour.** Haematuria in a long-term analgesic user needs urological review. Cystoscopy and urine cytology or upper tract imaging are the usual steps, because urothelial carcinoma is the classic association. 6. **Treat the cause.** Stop the offending analgesic, achieve glycaemic control or relieve obstruction, and treat infection with culture-guided antibiotics. Early withdrawal of the drug gives the best chance of preserving function. ## Where the exam tries to catch you Questions on this topic usually turn on the cause, the sign or the association that follows. - **Trap:** choosing ultrasound as the key investigation. — **Correct:** excretory urography or CT showing the ring sign is the classic answer, since ultrasound can miss early papillary necrosis. - **Trap:** treating analgesic nephropathy as only a kidney-failure problem. — **Correct:** the classic exam association is urothelial carcinoma of the renal pelvis or bladder, so haematuria in such patients needs urological review. - **Trap:** listing NSAIDs as the only cause of papillary necrosis. — **Correct:** diabetes, sickle cell disease and obstruction are equally common exam answers and should be remembered as a set. ## Frequently asked questions ### Which imaging sign is classic for renal papillary necrosis? The classic sign is a ring-shaped shadow on excretory urography or CT, produced when contrast outlines a necrotic renal papilla. Papillary calcification and calyceal clubbing can also be seen on the same study. This ring sign is the answer most often expected in NEET-PG questions on renal papillary necrosis. ### Why is analgesic nephropathy linked to urothelial carcinoma? Analgesic nephropathy is classically associated with urothelial tumours of the renal pelvis, ureter and bladder, which is why it appears in a triad with interstitial nephritis and papillary necrosis. The exact mechanism is debated, but drug metabolites concentrated in the medulla and urine are thought to contribute. Haematuria in a long-term analgesic user therefore needs urological evaluation. ### Does diabetes mellitus cause renal papillary necrosis? Yes, diabetes mellitus is one of the classic causes of renal papillary necrosis. Diabetic papillary necrosis often coexists with urinary tract infection or acute pyelonephritis, and it can be bilateral. Good glycaemic control and early treatment of infection are part of managing the condition in diabetic patients. ### What is the main treatment for renal papillary necrosis? Treatment of renal papillary necrosis consists of withdrawing the offending drug, correcting the underlying cause such as poor glycaemic control, and relieving any urinary obstruction. Infection is treated with antibiotics guided by urine culture. Any chronic kidney disease that follows is managed as it would be in other causes of CKD. ### Which condition must be excluded when papillary necrosis presents with sterile pyuria? Renal tuberculosis is the key mimic to exclude when papillary necrosis presents with sterile pyuria. It also causes papillary necrosis, so urine acid-fast bacilli culture or PCR should be sent when suspicion persists. Missing it delays a treatment path quite different from analgesic injury.