Pyelonephritis

Background

Definitions

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

Genitourinary infection

"UTI" frequently refers specifically to acute cystitis, but may also be used as a general term for all urinary infections; use location-specific diagnosis.

• Acute cystitis ("UTI")
• Pyelonephritis
• Urethritis
• Chronic cystitis
• Infected nephrolithiasis
• Prostatitis
• Renal abscess/perinephric abscess
• Emphysematous pyelonephritis

Evaluation

Clinical Features

• Pyelo = Cystitis symptoms 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

• Urinalysis 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
  • AAA
  • Renal artery embolism
  • Renal vein thrombosis
  • Aortic dissection
  • Mesenteric ischemia
• Renal
  • Pyelonephritis
  • Papillary necrosis
  • Renal cell carcinoma
  • Renal infarct
  • Renal hemorrhage
• Ureter
  • Blood clot
  • Stricture
  • Tumor (primary or metastatic)
• Bladder
  • Tumor
  • Varicose vein
  • Cystitis
• GI
  • Biliary colic
  • Pancreatitis
  • Perforated peptic ulcer
  • Appendicitis - pyelonephritis is common misdiagnosis in pregnancy; appendix may be pushed to RUQ
  • Inguinal Hernia
  • Diverticulitis
  • Cancer
  • Bowel obstruction
• Gynecologic
  • Ectopic Pregnancy
  • PID/TOA
  • Ovarian cyst
  • Ovarian torsion
  • Endometriosis
• GU
  • Testicular torsion
  • Epididymitis
• Other
  • Shingles
  • Retroperitoneal hematoma/abscess/tumor
  • Epidural abscess
  • Epidural hematoma

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
  • Uterine/bladder/vaginal prolapse
  • Fistula
  • Cystocele
• Other
  • Diverticulitis
  • Behavioral symptom without detectable pathology

Management

Antibiotics

Treatment is targeted at E. coli, Enterococcus, Klebsiella, Proteus mirabilis, S. saprophyticus

Outpatient

Consider one dose of Ceftriaxone 1g IV or Gentamycin 7mg/kg IV if the regional susceptibility of TMP/SMX or Fluoroquinolones is <80%

• Ciprofloxacin 500mg BID x 7 days OR
• Cefpodoxime 200 mg BID x10-14 days OR
• Levofloxacin 750mg PO once x 7 days

Adult Inpatient Options

• Ciprofloxacin 400mg IV q12hr OR
• Ceftriaxone 1gm IV QD OR
• Cefotaxime 1-2gm IV q8hr OR
• Gentamicin 3mg/kg/day divided q8hr +/- ampicillin 1–2 gm q4hr OR
• Piperacillin/Tazobactam 3.375 gm IV q6hr OR
• Cefepime 2gm IV q8hr OR
• Imipenem 500mg IV q8hr

Pediatric Inpatient Options

• Ceftriaxone 75mg/kg IV once daily
• Cefotaxime 50mg/kg IV q8hrs
• Ampicillin 25mg/kg IV q6hrs + Gentamicin 2.5mg/kg IV q8hrs

Disposition

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

Disposition

• Admit all second trimester pregnant patients with OBGYN consult
• Urology consult during the inpatient admission for pediatric patients due to the risk for urologic scarring
• Consider advanced imaging to rule out abscess of urolithiasis if patient has failed 3 days of therapy

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 with obstructed pyelo
   3. Associated with DM and Renal Stones
   4. Also occurs due to bacteremia with hematogenous seeding (Staph)
3. Emphysematous pyelonephritis
   1. Rare gas-forming infection nearly always occurring in patients with DM and obstruction
      1. Patients appear toxic and septic; nephrectomy may be required

See Also

• Urinary tract infections
• Dysuria

References

Authors

Ross Donaldson, Yos Yachivev, Jordan Swartz, Neil Young, Daniel Ostermayer