1. Urinary Tract Infections & Tubulointerstitial Kidney Diseases
Course: IDPT 5005
School of Medicine, UCDHSC
Francisco G. La Rosa, MD
Associate Professor, Department of Pathology
University of Colorado Denver Health Sciences Programs, Denver, Colorado 80045

2. Urinary Tract

3. ANATOMY OF THE KIDNEY 1. Renal Vein 2. Renal Artery 3. Renal Calyx
4. Medullary Pyramid
5. Renal Cortex
6. Segmental Artery
7. Interlobar Artery
8. Arcuate Artery
9. Arcuate Vein
10. Interlobar Vein
11. Segmental Vein
12. Renal Column
13. Renal Papillae
(papillary or Bellini’s ducts)
14. Renal Pelvis
15. Ureter

4. Kidney: Normal Histology

5. Kidney: Normal Histology

6. Urinary Tract Infections
Common
Mostly confined to lower GU tract (cystitis)
May involve upper GU tract (pyelonephritis, calculi)
Chronic pyelonephritis
Associated with obstruction, VU-reflux
Chronic renal failure
Hypertension

7. Prevalence of bacteriuria in different age groups:

8. Urinary Tract Infections: Routes of Infection
Ascending infection – most common
E. coli (~70%) – uropathogenic strains
Proteus, Pseudomonas, Klebsiella, etc. (recurrent, hospital acquired)
Hematogenous
Debilitated patients
Kidney injury
S. aureus (catalase +), group A Strep, opportunistic (immunocompromised)
Clinical setting: septicemia, endocarditis

10. Urinary Tract Infections: Pathogenesis
Virulence Factors
Host Defenses

11. Urinary Tract Infections: Pathogenesis
Host Defenses
Virulence Factors
uropathogenic
Bacterial Adhesion: Pili (P or fimbria)
“O” Antigens (certain strains more resistant)
Endotoxin (↓ ureteric peristalsis)

12. “P” Pili

13. Cultured epithelial cells
Bacterial Adhesion
DAPI
4'-6-Diamidino-2-phenylindole
Cultured epithelial cells
+ E. coli
Fluorescein-labeled
“Anti-P” fimbria

14. “O” Antigens (certain strains
more resistant)

15. Urinary Tract Infections: Pathogenesis
Virulence Factors
Host Defenses
Mechanical (Hydrokinetic)
Chemical (Urine)
Immunological
Cellular

16. Urinary Tract Infections: Pathogenesis – Host Defense
Mechanical:
Bladder emptying/ urine flow
Ureteric peristalsis
Mucus
Chemical:
Prostatic secretions (antibacterial)
Urine osmolality, pH, Ammonia
Blood group Ag’s (P2<<P1)

17. Urinary Tract Infections: Pathogenesis – Host Defense
Immunological:
Ig A
Complement
Cellular:
PMNs
Sheding urothelial cells

18. Urinary Tract Infections: Pathogenesis – Predisposing Factors
Females > Males
Short urethra
Bacterial colonization
Urethral trauma (“honeymoon” cystitis)
Instrumentation
Decreased urine flow / urine stasis
Incomplete voiding
Urinary tract obstruction
Diverticulum
Neurogenic bladder
Calculi
Vesicoureteral reflux
Immune compromise
Kidney / UT disease
Pregnancy

19. Urinary Tract Infections: Clinical Manifestations
Symptoms
Covert bacteriuria
Symptomatic UTI:
Reflective of level of infection
Recurrent infection in males usually indicates UT disease
Early childhood:
symptoms nonspecific
Irritability, convulsions

22. Urinary Tract Infections: Complications
Recurrence
Acute pyelonephritis
Renal/perinephric abscess
Papillary necrosis (diabetes)
Staghorn calculi (Proteus)
Chronic pyelonephritis/renal scarring

23. Acute pyelonephritis

24. Acute pyelonephritis

25. Acute & Chronic Pyelonephritis

26. microabscesses

27. Necrotizing papillitis
Pyonephrosis

28. Staghorn calculus

29. Urinary Tract Infections: Chronic Pyelonephritis
Causes:
Urinary tract obstruction
Vesicoureteral reflux (VUR)

30. Urinary Tract Obstruction: Relationship with infection
Obstruction predisposes to infection
Obstruction interferes with eradication
Obstruction predisposes to recurrence
Obstruction + Infection
↑ pressure
inflammation
ischemia
direct injury
Chronic pyelonephritis

31. Causes of Urinary Tract Obstruction:
Intrinsic
Exophytic: tumors of UT
Calculi
Sloughed necrotic papillae
Blood clots
Stricture
Urethral valves
Extrinsic compression
Tumors (pelvic, retroperitoneal)
Retroperitoneal fibrosis
Hemorrhage
Iatrogenic
Functional
Neurologic disease DM
Idiopathic

32. Urinary Tract Obstruction: Consequences
Hydronephrosis
Infection
Acute
Recurrent / persistent
Chronic obstructive pyelonephritis
Renal failure
Hypertension

33. Urinary Tract Obstruction: Hydronephrosis

34. Urinary Tract Obstruction: Hydronephrosis

35. Vesicoureteral reflux (VUR)

36. Vesicoureteral reflux (VUR)
Primary
Congenital abnormality of VU anatomy
Common in infants
Decreases in freq & severity during childhood
Usually mild
Secondary
Congenital malformations
Neurogenic bladder (paraplegia, spina bifida)
Obstruction
Older children, adults

38. Normal
VUR

39. Vesicoureteral reflux (VUR)

40. Reflux Nephropathy: Chronic Non-obstructive Pyelonephritis
Severe, persistent reflux + infection
Allows organisms to access renal parenchyma
Renal scars directly over dilated calyces
More extensive at poles (compound vs. simple papillae)
Often unilateral or unequal bilateral

41. Typical coarse scars of chronic pyelonephritis associated with vesicoureteral reflux. The scars are usually polar and are associated with underlying blunted calyces.

42. Reflux Nephropathy

43. Reflux Nephropathy:

44. Reflux Nephropathy: Chronic Non-obstructive Pyelonephritis
Micro: Atrophy, “periglomerular fibrosis”
Focal Segmental Glomerulosclerosis) (?)
Chronic renal failure
Hypertension

46. Questions?

47. Disclaimer:
The images and texts presented in this slide show are solely for educational purposes and not intended for commercial or pecuniary benefit. The images have been obtained from Dr. La Rosa’s personal collection, from text books used during the teaching of this chapter, and from published articles and educational works. Reproduction of these images can be done only for educational use.
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