Pyelonephritis

Background

Definitions

• UTI = significant bacteriuria in presence of symptoms
  • Described by location: urethritis, cystitis, or pyelonephritis

Diagnosis

Clinical Features

• Pyelo = Cystitis sx AND fever/chills/nausea/vomiting
  • CVAT alone may be referred pain from cystitis
  • CVAT is only physical examination finding that increases likelihood of a UTI

Labs

• UA with clumps and/or high WBCs
  • Nitrite
    • Very high specificity (>90%) in confirming diagnosis of UTI
    • Low sensitivity (enterococcus, pseudomonas, acinetobacter are not detected)
• Urine culture

Blood cultures are NOT indicated (organisms in blood culture matched those in urine culture 97% of time)

Imaging

• Consider if any of the following:

1. History of Renal Stone
2. Poor response to antibiotics
3. Male
4. Elderly
5. Diabetic
6. Severely ill

Differential Diagnosis

Major

• Acute cystitis
• Infected kidney stone

Flank Pain

• Vascular
  • Abdominal aortic aneurysm
  • Renal artery embolism
  • Renal vein thrombosis
  • Aortic dissection
  • Mesenteric ischemia
• Renal
  • Pyelonephritis
  • Perinephric abscess
  • Perinephric hematoma
  • Papillary necrosis
  • Renal cell carcinoma
  • Obstructive uropathy
    • May or may not be due to nephrolithiasis
  • Renal infarction
  • Renal hemorrhage
• Ureter
  • Nephrolithiasis
  • Blood clot
  • Stricture
  • Tumor (primary or metastatic)
• Bladder
  • Tumor
  • Varicose vein
  • Cystitis
• GI
  • Biliary colic
  • Pancreatitis
  • Perforated peptic ulcer
  • Appendicitis (appendix may be pushed to RUQ in pregnancy)
  • Inguinal Hernia
  • Diverticulitis
  • Cancer
  • Bowel obstruction
• Gynecologic
  • Ectopic Pregnancy
  • PID/TOA
  • Ovarian cyst
  • Ovarian torsion
  • Endometriosis
  • Mittelschmerz or benign ovulatory pain
• GU
  • Testicular torsion
  • Epididymitis
• Other
  • Shingles
  • Lower lobe pneumonia
  • Retroperitoneal hematoma, abscess, or tumor
  • Epidural abscess
  • Epidural hematoma
  • Rib contusion/fracture

Dysuria

• Genitourinary infection
  • Acute cystitis ("UTI")
  • Pyelonephritis
  • Urethritis
  • Chronic cystitis
  • Infected nephrolithiasis
  • Prostatitis
  • Epididymitis
  • Renal abscess/perinephric abscess
  • Emphysematous pyelonephritis
• Nephrolithiasis
• Urethral issue
  • Urethritis
  • Urolithiasis
  • Urethral foreign body
  • Urethral diverticulum
  • Allergic reaction (contact dermatitis)
  • Chemical irritation
  • Urethral stricture or obstruction
  • Trauma to vagina, urethra, or bladder
• Gynecologic
  • Vaginitis/cervicitis
  • PID
  • Genital herpes
  • Pelvic organ prolapse
  • Fistula
  • Cystocele
• Other
  • Diverticulitis
  • Interstitial cystitis
  • Behavioral symptom without detectable pathology

Disposition

• Discharge
  • Consider if young, otherwise healthy, tolerating PO
• Admission
  • Consider if elderly, Renal Calculi, obstruction, recent hospitalization/instrumentation, DM

Complications

1. Acute bacterial nephritis
   1. CT shows ill-defined focal areas of decreased density
2. Renal/Perinephric Abscesses
   1. Sign/symptoms similar to pyelo (fever, CVAT, dysuria)
   2. Occurs in setting of ascending infection w/ obstructed pyelo
   3. Associated w/ DM and Renal Stones
   4. Also occurs due to bacteremia w/ hematogenous seeding (Staph)
3. Emphysematous pyelonephritis
   1. Rare gas-forming infection nearly always occurring in pts w/ DM and obstruction
      1. Pts appear toxic and septic; nephrectomy may be required

See Also

• Urinary tract infections
• Dysuria