What are the symptoms and treatment of pyelonephritis?

Symptoms and Treatment of Pyelonephritis

Pyelonephritis typically presents with fever (>38°C), chills, flank pain, nausea, vomiting, or tenderness at the costovertebral angle, with or without symptoms of cystitis. 1, 2

Clinical Presentation

• Systemic symptoms include high fever, malaise, vomiting, abdominal or flank pain, and tenderness 1
• Flank pain is nearly universal in adults, and its absence should raise suspicion of an alternative diagnosis 3
• Symptoms can range from a mild pyrexial illness to life-threatening sepsis 4
• Lower urinary tract symptoms (frequency, urgency, dysuria) may also be present but are variable 4
• Chills often accompany the fever, indicating bacteremia 1, 2

Diagnostic Approach

• Urinalysis, including assessment of white and red blood cells and nitrite, is recommended for routine diagnosis 1, 2
• The combination of leukocyte esterase and nitrite tests has a sensitivity of 75-84% and specificity of 82-98% for UTI, though negative results don't exclude pyelonephritis 5, 4
• Urine culture with antimicrobial susceptibility testing should be performed in all cases of pyelonephritis before initiating antibiotics 1, 2, 6
• Blood cultures should be reserved for patients with uncertain diagnosis, immunocompromised status, or suspected hematogenous infections 5
• Imaging is not necessary in uncomplicated cases with good response to treatment 6

Treatment Algorithm

Outpatient Management (for uncomplicated cases):

• Oral fluoroquinolones are first-line therapy if local resistance is <10%:
  • Ciprofloxacin 500-750 mg twice daily for 7 days 2
  • Levofloxacin 750 mg once daily for 5 days 2
• If local fluoroquinolone resistance exceeds 10%, give one dose of a long-acting parenteral antibiotic (e.g., ceftriaxone) followed by oral therapy 6
• Other oral options include extended-spectrum penicillins, amoxicillin-clavulanate, cephalosporins (though oral cephalosporins achieve lower blood concentrations than IV) 1, 5
• Standard treatment duration is 7-14 days 2, 5

Inpatient Management (for complicated cases):

• Indications for hospitalization:
  • Severe illness or sepsis
  • Persistent vomiting
  • Failed outpatient treatment
  • Extremes of age
  • Pregnancy (high risk of complications)
  • Suspected obstruction or complication 5, 6
• Parenteral treatment options:
  • Ciprofloxacin 400 mg twice daily 2
  • Levofloxacin 750 mg once daily 2
  • Cefotaxime 2 g three times daily 2
  • Ceftriaxone 1-2 g once daily 2
  • Cefepime 1-2 g twice daily 2
  • Aminoglycoside with or without ampicillin 5

Follow-up and Treatment Failure

• Most patients respond to appropriate management within 48-72 hours 6
• Urine culture should be repeated 1-2 weeks after completion of antibiotic therapy 5
• If no improvement after 48-72 hours, consider:
  • Repeat blood and urine cultures
  • Imaging studies (contrast-enhanced CT recommended)
  • Resistant organisms
  • Underlying anatomical/functional abnormalities
  • Immunosuppressed states 1, 5
• In cases of urinary tract obstruction, urgent decompression should be pursued 6

Complications

• Renal scarring is the most severe long-term sequela of pyelonephritis 1
• Can lead to accelerated nephrosclerosis, hypertension, and chronic renal failure, though long-term risk is now considered low 1
• Approximately 15% of children show evidence of renal scarring after first UTI episode 1
• In rare cases, chronic granulomatous interstitial nephritis can develop as a complication 7