questions 2

Renal Papillary Necrosis

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Topic updated on 07/23/17 11:54am

Snapshot
  • ring signA 60-year-old woman presents to the emergency room with fever, chills, sudden flank pain, and gross hematuria. She has a history of recurrent urinary tract infections. Urinalysis reveals pyuria, hematuria, proteinuria, and dead tissue. An intravenous urography is obtained, revealing a ring sign. She is immediately given hydration and appropriate antibiotics.
Introduction
  • Clinical definition
    • necrosis and sloughing of renal papillae
  • Epidemiology
    • incidence
      • 30-40% in those with sickle cell disease or trait
    • demographics
      • middle-aged adults
      • uncommon in children, except in those with sickle cell disease or trait
    • risk factors
      • sickle cell disease or trait
      • acute severe pyelonephritis
      • analgesics such as NSAIDs
        • one of the most common and preventable risk factors
        • phenacetin
      • diabetes mellitus
      • tubulointerstitial nephritis
      • kidney stones causing obstruction
      • indinavir (anti-retroviral drug)
      • congenital urinary tract obstructions such as posterior urethral valves
      • shock
  • Pathogenesis
    • in sickle cell disease or trait
      • increased blood viscocity in the renal medulla causes renal papillary infarcts
        • the renal medulla has a low oxygen tension resulting in red blood cell sickling
    • in analgesic use
      • NSAIDs inhibits prostaglandin synthesis
        • prostaglandins promote vasodilation
  • Prognosis
    • prognostic variable
      • negative
        • concomitant diabetes
        • older age
Presentation
  • History
    • may be chronic and asymptomatic or acute
    • gross blood in urine
    • may have history of recent infection or autoimmune flare
    • pyelonephritis
  • Symptoms
    • primary symptoms
      • fever and chills
      • sudden onset flank or abdominal pain
    • may be asymptomatic
  • Physical exam
    • tenderness to palpation in the flank or abdomen
Imaging
  • This clinical image of angiogram shows the string-of-beads appearance of fibromuscular dysplasia.Radiographs
    • indications
      • if obstruction such as kidney stones is suspected
      • not diagnostic
    • recommend views
      • kidneys, ureters, and bladder (KUB)
    • findings
      • hydronephrosis from obstruction
      • may visualize kidney stones
  • CT
    • indications
      • typically performed if patient presents with hematuria, even if renal papillary necrosis is suspected, as hematuria can indicate malignancy in the bladder
      • if renal obstruction is suspected
      • most accurate test
    • views
      • CT of abdomen and pelvis
    • findings
      • hydronephrosis
      • kidney stones
      • ring shadows in medullae
      • loss of papillae
  • Intravenous urography
    • indications
      • if CT scan is inconclusive and suspicious for renal papillary necrosis remains high
      • if there is no suspicion of obstruction but suspicion of renal papillary necrosis remains high
    • findings
      • shrinkage of renal papillae
      • ring shadow from desquamated papillae - “ring sign”
      • filling defect in renal pelvis
      • contrast-containing tiny cavities in papillae
Studies
  • Labs
    • serum creatinine
      • if there is a sudden rise in creatinine, consider renal papillary necrosis in patient with diabetes or chronic urinary obstruction
  • Urinalysis
    • best initial test and results may show
      • hematuria
      • pyuria
      • proteinuria
      • sloughed papillae
Differential
  • Nephrolithiasis         
    • kidney stone seen on imaging without evidence of renal papillary necrosis
  • Tubulointerstitial nephritis
    • often presents with rash, arthralgias, and eosinophilia in the urine

 

Treatment
  • Conservative
    • avoid analgesics or any other nephrotoxic medications
  • Medical
    • supportive care with fluid resuscitation
      • indications
        • for all patients
    • antibiotics
      • indications
        • if pyelonephritis is suspected
Complications
  • Chronic pyelonephritis
  • Sepsis


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Qbank (1 Questions)

TAG
(M2.RL.32) A 78-year-old male with a history of herpes zoster and debilitating osteoarthritis presents to general medical clinic with painless hematuria. He has significant deformity in multiple joints. He reports that his ankles are giving him the most trouble, and he is scheduled for ankle replacement in the coming months. However, he is quite concerned that his recent urinary symptoms may prevent him from going to surgery. Vital signs are stable. Physical is within normal limits. He has no groin pain, flank pain, or costovertebral angle tenderness. There is no blood at the urethral meatus. Urinary analysis reveals 2+ heme. Routine labs are drawn, and serum creatinine is 3.5. Which drug is most likely to result in these symptoms, and if a renal biopsy is taken, what would one expect to find? Topic Review Topic

1. Drug: naproxen; Biopsy: papillary necrosis and chronic tubulointerstitial nephritis
2. Drug: naproxen; Biopsy: segmental sclerosis and hyalinosis
3. Drug: naproxen; Biopsy: wire looping of capilaries
4. Drug: acyclovir; Biopsy: antibodies to the glomerular basement membrane
5. Drug: acyclovir; Biopsy: split basement membrane

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