UT Radiology Knoxville GU Lecture Series

1. Renal
Infectious/Inflammato
ry Disease
Jud Gash, MD

2. Outline








Pyelonephritis
Renal Abscess
Emphasematous Pyelonephritis
Pyonephrosis
Xanthogranulomatous Pyelonephritis
TB
Renal Malakoplakia
Other Infection

3. Pyelonephritis

Predisposition

Most cases similar to lower UTI causes (esp intercourse)



About 20-30:1 cystitis to PN
Female, reflux, obstruction, stones, diabetes, stasis
(congenital anomalies, diverticula), pregnancy
Clinical


Gram negatives (E coli, Proteus, Pseudomonas, etc.)
Flank pain and tenderness, fever, N/V, signs of cystitis

4. Pyelonephritis

Imaging


Usually not necessary (uncomplicated PN)
Reasons to image
Uncertain diagnosis
 Severe symptoms
 Atypical clinical situation


men, unresolving, children, diabetics
Role out obstruction
 Evaluate source in recurrent pyelonephritis



May see incidentally
Note: imaging of PN/UTI in children whole separate
topic

5. Pyelonephritis

Pathophysiology

Ascending Infection


Adhesions and
Endotoxins
Ureteropyelitis



Pyelonephritis



Thickened, enhancing
Urothelium
Ureteral “ileus”
Access/spread via
papilla
Wedge shaped and
patchy
Rarely hematogeneous


Staph
Bilateral

6. Ultrasound

Role
Detect Complications



Pyonephrosis; abscess
Predisposing factors
Scarring




Imaging
Normal (75%?)
Enlargement
Loss of corticomedullary
junction
Decreased Echogenecity


Hyperechoic (hemorrhage)


Focal or diffuse
Focal
Hypoechoic area on Power
Doppler

7. Severe unilateral acute bacterial pyelonephritis
Craig W D et al. Radiographics 2008;28:255-276

8. Craig W D et al. Radiographics 2008;28:255-276

9. Pyelonephritis
Radiographics. 2000;20:215-243
Craig W D et al. Radiographics 2008;28:255-276

10. Pyelonephritis

CT

Noncontrast

Normal
Nephromegaly
 Perinephric stranding
 Loss of hyperdense pyramids
 Hyperdensities (hemorrhage)
 Thickening of urothelium
 Mild ureteral dilation
Contrast
 Wedges of hypoattenuation (edema, obstruction, and vasospasm)
 Dense on delayed
 Striations (focal, diffuse)
May be abnormal for days or weeks
Role







Diagnosis/alternative diagnosis
Acute complications
Underlying predispositions (CTU)

11. ED – flank pain (no stone seen)

12. Pyelonephritis

DDX





PN
Recent stone passage
Non-stone obstruction (clot,
fungus ball, iodinovir)
Acute vascular lesion (RA, RV
occlusion)
So, non-contrast findings
nonspecific.


Clinical exam/UA/hydro should
allow distinction
Consider contrast if unclear
RadioGraphics 2004;24:S11-S28

13. Craig W D et al. Radiographics 2008;28:255-276

14. Craig W D et al. Radiographics 2008;28:255-276

15. Pyelonephritis
RadioGraphics 2004;24:S11-S28

16. Pyelonephritis
Kawashima A - Infect Dis Clin North Am - 01-JUN-2003

17. Acute bacterial pyelonephritis caused by hematologic
seeding in a patient with Staphylococcus aureus
endocarditis
Craig W D et al. Radiographics 2008;28:255-276

18. Pyelonephritis – DDX (3 I’s)
Radiographics. 2000;20:215-243

19. Pyelonephritis

Focal Pyelonephritis
Replaces old terms (FLN,
ABN, etc.)
 May be pre-abscess state
 Now focal or diffuse
pyelonephritis
 Imaging


Focal mass-like lesion can
mimic tumor

20. Complications of Pyelonephritis

Acute

Abscess





Renal
Perinephric
Emphysematous PN
Pyonephrosis
Chronic



Scarring/Atrophy
XGP/malakoplakia
Papillary Necrosis

21. Abscess

Etiology
PN which proceeds to tissue necrosis and
liquefaction
 More likely with obstruction, diabetes (75% of all
abscesses), stone disease
 Normal kidneys or superinfect pre-existing lesions
(cysts, diverticula, RCC)
 Can spread to perinephric space


22. Abscess

Imaging

US


CT



Rounded, thick wall cystic
mass with debris
Rounded cystic lesion with
enhancing wall
Surrounding inflammatory
changes
Microabscesses

Small, often multiple areas
in the setting of PN
RadioGraphics 2004;24:S11-S28

23. Perinephric Abscess

Usually secondary
to pyonephrosis

Less commonly in
unobstructed PN
Kawashima A - Infect Dis Clin North Am - 01-JUN-2003

24. Emphysematous Pyelonephritis





Aggressive form of PN with necrosis, vascular
compromise and air production
Rare life threatening form urologic emergency
90% diabetics (poorly controlled)
Obstruction common (must exclude)
Adults


Rare, if ever, seen in pediatrics
Clinical presentation


Fever, flank pain, lethargy, renal failure, septic shock
Usually gram negatives, esp. E. Coli

25. Emphysematous Pyelonephritis

KUB



Gas collections
Renal Enlargement
Stones
Radiographics. 2002;22:543-561

26. Emphysematous Pyelonephritis

27. Emphysematous Pyelonephritis

28. Emphysematous Pyelonephritis

29. Emphysematous Pyelonephritis
Radiographics. 2002;22:543-561

30. Emphysematous Pyelonephritis

US
Hyperechoic dirty
shadowing
 DDX: nephrocalcinosis
and nephrolithiasis


31. Emphysematous Pyelonephritis
Radiographics. 2002;22:543-561

32. Emphysematous Pyelonephritis

CT
Parenchymal air – bubbles,
linear
 Severe inflammatory
changes
 Look for obstruction

Kawashima A - Infect Dis Clin North Am - 01-JUN-2003

33. Emphysematous Pyelonephritis

Treatment
Nephrectomy –
traditional gold
standard
 If more limited,
milder form –
percutaneous
drainage/relief of
obstruction and
antibiotics

Radiographics. 2002;22:543-561

34. Emphysemtous pyelitis



Gas in collecting
system
Same epidemiology
as EPN
Better prognosis

Relief of
obstruction/ABX

35. Emphysemtous pyelitis
Air In Collecting System



Emphysematous Pyelitis
Fistula
Iatrogenic
Radiology. 2001;218:647-650

36. Pyonephrosis


Obstructed, infected kidney
Cause of obstruction


Stones (rarely other: Conj UPJ, tumor)
Emergency
Urosepsis
 Renal destruction
 XGP (chronic)


Treatment

Drainage (perc neph/stent and antibiotics)

37. Pyonephrosis

US




Large, hypoechoic kidney
Hydronephrosis
Echogenic debris
Fluid – Fluid Level
Kawashima A - Infect Dis Clin North Am - 01-JUN-2003

38. Pyonephrosis – 4 cases

39. Pyonephrosis

CT



Findings of infection
Findings of obstruction
Hypedense/debris in collecting
system


Thick pelvic pelvic wall (2-5mm)



>30 hu (Note: 50%<15hu)
75% (Note: 10% of uninfected
obstruction)
Emphysematous pyelitis in 10%
Aspirate Urine

40. Chronic Pyelonephritis


Controversial
Pathophysiology
Findings
Renal Scarring
 Calyceal Clubbing
 At Renal Poles


DDX

Renal infarcts

41. Xanthogranulomatous Pyelonephritis
(XGP)


Disorder immune response in
setting of chronic infection, often
with obstruction and stones (ie
pyonephrosis)
Pathophysiology




Stone leads to obstruction
Caliectasis (peripelvic fibrosis limits
pelviectasis).
Infection leads to parenchymal
destruction and replacement with
lipid laden macrophages
Treatment

nephrectomy
Radiographics. 2000;20:215-243

42. Xanthogranulomatous Pyelonephritis
(XGP)

Key points

Middle age women with longstanding
infection/stones


DM in only 10%
Triad
Nonfunction
 Renal enlargement



Caliectasis with less pelviectasis, parenchymal loss
Stones (90%)

Staghorn, exploded

43. Xanthogranulomatous Pyelonephritis
(XGP)

KUB


“exploded” staghorn
with large renal
shadow
US
Caliectasis (massive)
with debris
 Stones

Kawashima A - Infect Dis Clin North Am - 01-JUN-2003

44. Xanthogranulomatous Pyelonephritis
(XGP)

CT


“Bear Claw”
Massive caliectasis (without
pelviectasis)



Not fluid though
Parenchyma enhances (not
function)
Stones
Kawashima A - Infect Dis Clin North Am - 01-JUN-2003

45. Xanthogranulomatous pyelonephritis
Craig W D et al. Radiographics 2008;28:255-276
©2008 by Radiological Society of North America

46. Xanthogranulomatous Pyelonephritis
(XGP)
Radiographics. 2000;20:215-243
Radiographics. 2000;20:215-243

47. Xanthogranulomatous Pyelonephritis
(XGP)

Other Findings




Extrarenal Extension
Nodes
Fistula
Segmental

48. Tuberculosis

Pathophysiology





Renal cortical
deposition occurs in
primary infection
Reactivation (one
kidney) in medulla
Descending process
Destruction, fibrosis,
calcification,
obstruction
Dx

Culture (sterile pyuria)

49. Tuberculosis

KUB
Diffuse or scattered
renal calcifications
(25%)
 Often small renal
shadow
 “putty kidney”

Kawashima A - Infect Dis Clin North Am - 01-JUN-2003

50. Tuberculosis

CTU (IVP)

Renal






Ureter





Moth eaten, fuzzy calyx with
papillary necrosis
Infundibular, pelvic fibrosis (purse
string pelvis)
Calyceal/pelvic obstruction
(hydrocalyx, phantom calyx)
Renal nonfunction
(autonephrectomy), scarring
calcification (putty kidney)
Note: renal changes mimic TCC
Ulcerations and irregularity;
sawtooth (early)
Multiple strictures; corkscrew
(later)
Short, strait, aperistaltic (latest)
Calcifications (DDX:
schistosomiasis)
Bladder involvement is very late
AJR 2005; 184:143-150

51. Renal Parenchyma Malakoplakia
(RPM)


Inflammatory condition to chronic E. coli infection
Disordered macrophage response to bacterial
phagocytosis


Entire GU tract can be affected



histologic hallmark is basophilic inclusions (MichaelisGutmann bodies) within large eosinophilic macrophages (von
Hansemann histiocytes)
Most commonly urothelial plaques (bladder esp.)
RPM occurs uncommonly
Usually middle age women with h/o chronic infection

Flank pain, fever

52. Renal Parenchyma Malakoplakia
(RPM)

Findings:
Bilateralor unilateral
 Focal, multifocal or
diffuse
 infiltrating masses
 Renal pelvis
involvement may
occur
 Calcifications
uncommon

Radiographics. 2000;20:215-243.)

53. Fungal Disease




Usually immunocompromised
(DM, steroids, HIV, etc.)
Candida most common
Any portion of urinary tract
Imaging


Changes of PN, abscess
Fungus ball in collecting system

Non-stone (echogenic) filling
defect

DDX: sloughed papilla, tcc, clot
Kawashima A - Infect Dis Clin North Am - 01-JUN-2003

54. Outline








Pyelonephritis
Renal Abscess
Emphasematous Pyelonephritis
Pyonephrosis
Xanthogranulomatous Pyelonephritis
TB
Renal Malakoplakia
Other Infection