II. Definitions
III. Causes
- Most Common
- Urinary Tract Infection Complication (75%)
- Staphylococcal Aureus Bacteremia
- Hematogenous spread
- In the pre-Antibiotic era, was the most common cause of Perinephric Abscess
- Less common source in developed countries
- Renal Trauma
- Regional contiguous infection spread
- Crohn's Disease
- Acute Cholecystitis
- Acute Appendicitis with rupture appendix
- Pelvic Inflammatory Disease
IV. Risk Factors
- Diabetes Mellitus
- Pregnancy
- Urinary Tract Infection
- Nephrolithiasis or Ureterolithiasis (found in 20% of cases)
- Vesicoureteral reflux
- Neurogenic Bladder
- Polycystic Kidney Disease
V. Symptoms
-
Fever (75%) and chills
- Fever often persists despite UTI infection management >4-5 days
- Flank Pain
-
Abdominal Pain
- Pain may be referred to inguinal region
- Frequently absent are Urinary Tract Infection symptoms
VI. Signs
-
Costovertebral Angle Tenderness (CVA Tenderness)
- Present in 75% of patients
VII. Labs
- Complete Blood Count
- Basic chemistry panel (e.g. chem8)
-
Urinalysis
- Normal urine does NOT exclude Perinephric Abscess
- Abscess may not communicate with collecting system
- Urine Culture
- Blood Cultures
- Consider ESR, C-RP
VIII. Imaging
-
CT Abdomen and Pelvis with contrast (preferred)
- Identifies abscess and contiguous involvement
- Excludes concurrent Ureterolithiasis
IX. Management
-
Antibiotics for 14-21 days
- Gram Negative Bacteria (most common in developed countries)
- See Acute Pyelonephritis
- Initial Antibiotics cover both urinary tract source and Staphylococcus aureus
- Staphylococcal Bacteremia (hematogenous seeding, less common)
- Coverage for MRSA with Vancomycin as indicated
- Standard MSSA coverage otherwise (e.g. Cefazolin, Nafcillin)
- Gram Negative Bacteria (most common in developed countries)
- Drainage
- Indicated in Perinephric Abscess >3 cm
- Drainage per local expert opinion for abscesses <3 cm (versus Antibiotics alone)
- Technique
- Percutaneous catheter (preferred)
- Surgical drainage (Urology)
- Indicated in Perinephric Abscess >3 cm
X. Prognosis
- Worse outcomes with Diabetes Mellitus, large abscess, advanced age, Renal Insufficiency
XI. Complications
- Septic Shock
- Fistula formation (e.g. Small Bowel)
- Renal Hemorrhage
- Contiguous spread (e.g. Pneumonia, peritoneal spread)
XII. References
- Lee (2008) Korean J Intern Med 23(3): 140-8
- Okafor (2019) Perinephric Abscess, StatPearls, NLM
- (2019) Sanford Guide, accessed on IOS, 10/11/2019