Acute Pyelonephritis Lecture Notes

Definitions

Acute Pyelonephritis: Rapid onset inflammation of the kidney, typically due to bacterial infection.
- Pyelo-: Pelvis
- Neph-: Kidney
- -itis: Inflammation
Urinary Tract Infection (UTI): Infection of any part of the urinary tract.
- Upper UTI: Includes kidneys and ureters.
- Lower UTI: Includes bladder and urethra.

Ascending Infection: Most common cause; bacteria move from urethra and bladder up to the kidney.
- Risk Factors: Female sex, sexual intercourse, indwelling catheters, diabetes mellitus, urinary tract obstruction.
- Vesicoureteral Reflux (VUR): Urine flows backward up the urinary tract.
  - Caused by congenital defects or bladder outlet obstruction.
  - Leads to urinary stasis, facilitating bacterial colonization.
Common Organisms:
- Ascending: E. coli, Proteus species, Enterobacter species.
- Hematogenous Spread: Less common, linked to septicemia or infective endocarditis.
  - Organisms: Staphylococcus species, E. coli.

Typically affects one kidney (unilateral).
Bacteria adhere to renal epithelium, triggering inflammation.
Neutrophils infiltrate, causing:
- White blood cells in urine.
- Formation of white blood cell casts.
Systemic symptoms: Increased white blood cells (leukocytosis), fever, chills, nausea, vomiting, flank pain.
Distinguishing factor from lower UTI: Systemic symptoms.

Diagnosis: Presence of white blood cells and white blood cell casts in urine.
Treatment: Antibiotics and hydration.
- Potential complications: Renal abscess, chronic pyelonephritis, papillary necrosis.

Acute pyelonephritis is a bacterial infection of the upper urinary tract, often from a lower UTI, especially with VUR.
Symptoms include systemic ones like fever and flank pain, treated with antibiotics.
Recurrence can lead to chronic conditions affecting kidney function.

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