Demetrius H. Bagley, MD, FACS
Kelly A. Healy, MD
BASICS
DESCRIPTION
• Renal papillary necrosis is ischemic necrosis of the papillae and occasionally the medullary pyramids.
• The clinical course may be acute and rapidly progressive or chronic
– Acute forms are symptomatic and may present with hydronephrosis, pyelonephritis, and hematuria
– Typically chronic forms are asymptomatic and discovered incidentally on radiographic studies
• Acute presenting symptoms include hematuria, flank or abdominal pain, and fever and chills
EPIDEMIOLOGY
Incidence
• Most cases occur after the 6th decade of life and papillary necrosis is uncommon in patients <40 yr
• Female > Male (1.1:1.0) (1)[B]
Prevalence
N/A
RISK FACTORS
• Include any condition causing ischemia that can predispose to the development of renal papillary necrosis. Many have >2 risk factors
• Diabetes mellitus
• Sickle cell trait or disease
• Analgesic abuse:
– Most commonly phenacetin and NSAIDs
• Antiretroviral treatment:
– Indinavir
• Urinary tract obstruction of any cause
• Pyelonephritis
• Systemic vasculitis
• Lupus nephritis
• Wegener granulomatosis
• Renal artery stenosis
• Systemic vasculitis
• Global ischemia:
– Shock, hypoxia, dehydration
Genetics
N/A
PATHOPHYSIOLOGY
• The renal papilla normally exists in the state of hypoxia because of the blood flow in the vasa recta which can be affected further with conditions that reduce blood flow
– Perfusion compromise in diabetes mellitus
– Diminution in blood flow because of sickling of blood cells (sickle cell disease)
– Infection that causes inflammation of the interstitium can lead to compression of the medullary vasculature
• Analgesic use causes COX inhibition and decreased prostaglandin production. This leads to decreased vascular perfusion, vasoconstriction and can cause ischemic necrosis
• Some medications can cause direct interstitial cell necrosis and decrease in prostaglandin production
• The necrotic, soft tissue can cause unilateral or bilateral ureteral obstruction
ASSOCIATED CONDITIONS
• Analgesic abuse
• Diabetes mellitus
• Pyelonephritis
• Sickle cell disease
• Urinary tract obstruction
GENERAL PREVENTION
• Treatment of underlying disorders including diabetes or sickle disease
• Avoidance of analgesic use
DIAGNOSIS
HISTORY
• May present with hematuria or obstruction with flank pain (2)
• With infection, fever, chills, dysuria, frequency, urgency, flank pain, and renal colic can occur
• Rarely, bilateral ureteral obstruction with necrotic tissue can present as acute oliguric renal failure
PHYSICAL EXAM
• Costovertebral angle tenderness
• Fever
DIAGNOSTIC TESTS & INTERPRETATION
Lab
• Urinalysis and urine culture:
– Proteinuria, pyuria, bacteriuria, and low urine-specific gravity
– Epithelial cells and casts may be present
• CBC may demonstrate leukocytosis
• Metabolic panel can demonstrate azotemia and elevated creatinine
Imaging
• CT has become the imaging modality of choice
• Contrast images show:
– Ring shadows in the medullae
– Contrast-filled clefts in the renal parenchyma
– Renal pelvic filling defects
• Excretory urography has historically been the gold standard for diagnosis
– Findings include shrinkage and irregularity of papilla defined by contrast materials as a ring shadow often in a triangular shape
– A calix without a papilla
– Filling defect in the renal pelvis or ureter
– Contrast containing rice-grain–sized cavities in the papilla
• Retrograde pyelogram:
– Useful in patients with azotemia, contrast sensitivity, or other situations where intravenous contrast is contraindicated
– Findings may reveal a club-shaped calyx or a filling defect in the ureter
Diagnostic Procedures/Surgery
Patient presenting with hematuria needs a full urologic workup even if papillary necrosis is confirmed.
Pathologic Findings
• The cortex features depressed areas of cortical atrophy (3)
• Papilla shows various stages of necrosis, desquamation, and sloughing
– Focal necrosis: Involves only the tip of the papilla
– Diffuse necrosis: The entire papilla and portions of the medulla are involved
• Microscopically, changes of papilla may be a patchy appearance or complete coagulative necrosis. Glomeruli are typically unchanged
DIFFERENTIAL DIAGNOSIS
• Acute tubular necrosis
• Nephrolithiasis
• Carcinoma of the ureter or bladder
• NSAID abuse and/or overuse
• Pyelonephritis
• Renal trauma
• TB
• Ureteral stricture disease
TREATMENT
GENERAL MEASURES
• Hydration, oral or intravenous
• Glycemic control, if diabetic
• Definition and treatment of sickle disease
MEDICATION
First Line
• Cessation of any associated/causative medications including analgesics
• Treatment of underlying cause of ischemia
• Broad-spectrum antibiotics, if associated with pyelonephritis
Second Line
N/A
SURGERY/OTHER PROCEDURES
• When a patient presents with acute urinary obstruction, drainage is indicated with percutaneous nephrostomy, ureteral stent placement, or endoscopic/ureteroscopic removal of obstructing sloughed tissue
• In the nonacute case, renal pelvic or ureteral filling defect can be electively evaluated with ureteroscopy
• Nephrectomy is rarely warranted
ADDITIONAL TREATMENT
Radiation Therapy
N/A
Additional Therapies
N/A
Complementary & Alternative Therapies
N/A
ONGOING CARE
PROGNOSIS
Depends on the basis for the ischemia, the compounding factors, and the amount of necrosis
COMPLICATIONS
• Infection may develop in the desquamated necrotic papilla
• Calculi can develop on the base of the sloughed papilla
• Obstruction can develop along the ureter from multiple sloughed papilla
FOLLOW-UP
Patient Monitoring
• Monitoring includes the kidney itself for further necrosis and for changes in function
• Causes of ischemia should be closely monitored
Patient Resources
http://www.scripps.org/articles/1151-renal-papillary-necrosis
REFERENCES
1. Vijayaraghavan SG, Kandasamy SV, Mylsamy A, et al. Sonographic features of necrosed renal papillae causing hydronephrosis. J Ultrasound Med. 2003;22(9):951–956.
2. Gordon M, Cervellione RM, Postlethwaite R, et al. Acute renal papillary necrosis with complete bilateral ureteral obstruction in a child. Urology. 2007;69:575e11–575e12.
4. Amuluru K, Erickson BA, Okotie O, et al. Bilateral ureteral obstruction from papillary necrosis secondary to household cleaner ingestion. Can J Urol. 2009;16(3):4701–4703.
ADDITIONAL READING
Chung DC, Kim SH, Jung SI, et al. Renal papillary necrosis: Review and comparison of findings at multi-detector row CT and intravenous urography. Radiographics. 2006;26:1827–1836.
See Also (Topic, Algorithm, Media)
• Diabetes Mellitus, Urologic Considerations
• Filling Defect, Upper Urinary Tract (Renal Pelvis and Ureter)
• Hematuria, Gross and Microscopic, Adult
• Nephropathy, Analgesic
• Papillary Necrosis, Renal Image 
• Sickle Cell Disease, Urologic Considerations
CODES
ICD9
• 584.7 Acute kidney failure with lesion of renal medullary [papillary] necrosis
• 590.80 Pyelonephritis, unspecified
• 591 Hydronephrosis
ICD10
• N12 Tubulo-interstitial nephritis, not spcf as acute or chronic
• N13.30 Unspecified hydronephrosis
• N17.2 Acute kidney failure with medullary necrosis
CLINICAL/SURGICAL PEARLS
Gross hematuria in a patient with sickle cell disease suggests papillary necrosis.