1. Perinephric Abscess Student Name: Jack Li Period: 3 Date: 7/22/09

2. History CC: “abdominal pain” HPI: 26 yo ♂ c/o worsening constipation x 2 wks, worsening constant/sharp R flank pain, BRBPR, 3x non- bloody emesis, Ø hematuria/dysuria, but + dark-colored urine and increased frequency, + fevers/chills PMH: acute hepatitis C, recent opioid dependence (IV heroin), PTSD, depression FHx: gout (father), recurrent kidney stones (uncle) SHx: prior smoker 10+ pack-yrs, hx EtOH, IVDU quit in march after suicide attempt, 1 sexual partner in last 1.5 yrs, lives in group home at VA Meds: suboxone, trazodone, venlafaxine Allergies: NKDA ROS: no weight change, CP, SOB, cough/wheeze, rash, headadches, or joint pain

3. Physical Exam and Labs Physical exam: –Vitals: T 99.6 HR 100 RR 18 BP 153/69 99% RA –Abdomen: R CVA tenderness, RUQ tenderness to palpation, voluntary guarding, no rebound tenderness, RLQ tenderness to palpation, no hepatosplenomegaly, normal bowel sounds –No other significant findings Labs: –WBC: 20.3 (87.9% neut.) –Hgb: 15.3 –Plts: 423 –Na 135, K 3.9, Cl 98, bicarb 24, BUN 15, Cr 0.8, Gluc 98 –protein 7.7, albumin 3.4 –AST/ALT/alk. phos: 18/27/143 –INR 1.5 –UA: - leuk. esterase/nitrite/blood, WBC 1-5

4. Findings Abdomen XR Moderate amount of feces within colon Otherwise unremarkable findings

5. Images

6. Findings Abdomen/Pelvis CT w/ contrast 3.1 x 4.6 cm geographic area of low attenuation associated the anterior aspect of the R lower pole of kidney contiguous extension along the lower pole to a fluid collection is located posteriorly coursing cephalad along the right lower pole, measuring 1.5 x 4.2 cm in greatest axial dimension marked inflammatory stranding within the right perinephric space and retroperitoneum, with fascial thickening

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10. Differential Diagnosis –Abscess/fluid collection –Cystic Masses Polycystic kidney disease Medullary sponge kidney nephronophthisis –Solid Masses Oncocytoma Angiomyolipoma Metanephric adenoma Chronic pyelonephritis Renal cell carcinoma

11. Diagnosis Perinephric Abscess

12. Pathophysiology: –Typically complications of UTIs –Gram negative enteric bacilli or polymicrobial –Can occur as part of hematological spread, usually due to S. aureus Clinical sxs: –Fever –Flank pain –Abdominal pain –Dysuria/frequency –+/- palpable mass Diagnosis: –Blood and urine cxs –Imaging – CT and/or ultrasound –Plain films not useful

13. CT Evaluation of morphology Findings may include enlargement of Gerota’s fascia, renal enlargement, parenchymatous inflammation, or lobar necrosis Advantages: More reliable diagnosis than USN Can be used to track abx therapy progression Guides management (>5cm = drainage) Disadvantages: Does not guide abx therapy Radiation exposure Expensive ($2000-$3000)

14. Other Imaging -Ultrasound -Can be used as interventional aid (i.e. for drainage) -Relatively inexpensive -14x higher risk of incorrect diagnosis if used alone -Plain films -Not used for diagnosis

15. Summary -Imaging for clinically suspected renal/perinephric abscess includes CT and USN -CT guides decision on intervention, antibiotic therapy Questions?

16. References Stojadinović M, Mićić S, Milovanović D. Ultrasonographic and computed tomography findings in renal suppurations: performance indicators and risks for diagnostic failure. Urol Int. 2008;80(4):389-97. Renal and perinephric abscess. UptoDate 2009. Dalla Palma L, Pozzi-Mucelli F, Ene V. Medical treatment of renal and perirenal abscesses: CT evaluation. Clin Radiol. 1999 Dec;54(12):792-7. Radiographic images obtained from VA CPRS/Stentor Cost information from Complete Guide to Medical Tests by H. Winter Griffin, MD