Perinephric AbscessPerinephric Abscess

Student Name: Jack LiPeriod: 3 Date: 7/22/09

HistoryHistory• 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

Physical Exam and LabsPhysical 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

FindingsFindings• Abdomen XR

• Moderate amount of feces within colon• Otherwise unremarkable findings

ImagesImages

FindingsFindings• 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

ImagesImages

ImagesImages

ImagesImages

Differential DiagnosisDifferential Diagnosis– Abscess/fluid collection– Cystic Masses

• Polycystic kidney disease• Medullary sponge kidney• nephronophthisis

– Solid Masses• Oncocytoma• Angiomyolipoma• Metanephric adenoma• Chronic pyelonephritis• Renal cell carcinoma

DiagnosisDiagnosis

Perinephric Abscess

Perinephric Abscess• 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

CTCT

• 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)

Other ImagingOther 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

SummarySummary- Imaging for clinically suspected

renal/perinephric abscess includes CT and USN

- CT guides decision on intervention, antibiotic therapy

Questions?

ReferencesReferences• 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