Renal papillary necrosis

Renal papillary necrosis is a form of nephropathy involving the necrosis of the renal papilla.[1] Lesions that characterize renal papillary necrosis come from an impairment of the blood supply and from subsequent ischemic necrosis that is diffuse.[2]

Renal papillary necrosis
Other namesRenal medullary necrosis[1]
Frontal section through the kidney
SpecialtyUrology, nephrology 
SymptomsBack pain, cloudy urine[1]
CausesDiabetic nephropathy, Kidney infection[1]
Diagnostic methodBlood and urine test[1]
TreatmentDepends on cause[1]

Signs and symptoms

Symptoms (and signs) consistent with renal papillary necrosis are:[1]

Causes

In terms of cause, almost any condition that involves ischemia can lead to renal papillary necrosis. A mnemonic for the causes of renal papillary necrosis is POSTCARDS: pyelonephritis, obstruction of the urogenital tract, sickle cell disease, tuberculosis, cirrhosis of the liver, analgesia/alcohol abuse, renal vein thrombosis, diabetes mellitus, and systemic vasculitis.[3] Often, a patient with renal papillary necrosis will have numerous conditions acting synergistically to bring about the disease.[4]

Analgesic nephropathy is a common cause of renal papillary necrosis. The risk is higher for phenacetin (which was withdrawn from market in the United States) and paracetamol (acetaminophen) compared to aspirin and other NSAIDs.

Pathophysiology

This condition is due to ischemia of the renal papillae, the portion of the kidney that collects urine from the nephron. The papillae are vulnerable to ischemia as they are supplied by small caliber arteries which are liable to obstruction. All of the underlying causes of papillary necrosis cause diminished flow through these arteries, either through direct mechanical obstruction (sickle cell), obstruction secondary to inflammation (vasculitides), or vasoconstriction (NSAIDs).[5] Papillary necrosis is more likely to develop when multiple of these underlying factors are present.[6] Ultimately, necrosis of the papillae results in sloughing into the lumen, causing hematuria. If the degree of necrosis is substantial post-renal failure may occur, though this is uncommon.[7]

Diagnosis
Cystoscope

Individuals with renal papillary necrosis due to excess use of analgesic have an elevated risk of epithelial tumors, hence a urine cytology exam is useful.[8] In terms of imaging this condition can be identified by retrograde pyelography (RGP).[9] The diagnosis of renal papillary necrosis is therefore done via:[10]

Treatment

Treatment of renal papillary necrosis is supportive, any obstruction (urethral) can be dealt with via stenting. This condition is not linked to a higher possibility of renal failure.[11] Control of infection is important, thus antimicrobial treatment is begun, so as to avert surgery (should the infection not respond).[12]

References
  1. "Renal Papillary Necrosis". Medline. NIH. Retrieved 15 October 2015.
  2. Jung, Dae Chul; Kim, Seung Hyup; Jung, Sung Il; Hwang, Sung Il; Kim, Sun Ho (November 2006). "Renal Papillary Necrosis: Review and Comparison of Findings at Multi–Detector Row CT and Intravenous Urography1". RadioGraphics. 26 (6): 1827–1836. doi:10.1148/rg.266065039. PMID 17102053.
  3. Kim, Seung Hyup (2011-11-19). Radiology Illustrated: Uroradiology. Springer Science & Business Media. p. 471. ISBN 9783642053221.
  4. Powell, Christopher. "Papillary Necrosis". Medscape Reference. Retrieved 10 Nov 2011.
  5. "Analgesic Nephropathy. Chronic kidney disease information. Patient | Patient". Patient. Retrieved 2015-10-15.
  6. Greenberg, Arthur; Cheung, Alfred K. (2005-01-01). Primer on Kidney Diseases. Elsevier Health Sciences. p. 387. ISBN 978-1416023128.
  7. Powell, Christopher (Jan 12, 2017). "Papillary Necrosis". Medscape.
  8. Wein, Alan J.; Kavoussi, Louis R.; Novick, Andrew C.; Partin, Alan W.; Peters, Craig A. (2011-09-28). Campbell-Walsh Urology. Elsevier Health Sciences. p. 269. ISBN 978-1455722983.
  9. Kim, Seung Hyup (2011-11-19). Radiology Illustrated: Uroradiology. Springer Science & Business Media. p. 472. ISBN 9783642053221.
  10. "Papillary Necrosis Workup: Laboratory Studies, Imaging Studies, Diagnostic Procedures". emedicine.medscape.com. Retrieved 2015-10-15.
  11. Schrier, Robert W. (2007-01-01). Diseases of the Kidney and Urinary Tract. Lippincott Williams & Wilkins. p. 2008. ISBN 9780781793070.
  12. Schlossberg, David (2015-04-23). Clinical Infectious Disease. Cambridge University Press. p. 438. ISBN 9781107038912.

Further reading
Classification
External resources
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