What is the treatment for pyelonephritis (infection of the kidney)?

Treatment of Pyelonephritis

Oral fluoroquinolones are the preferred first-line treatment for uncomplicated pyelonephritis in outpatients where local resistance rates are <10%, with options including ciprofloxacin 500-750 mg twice daily for 7 days or levofloxacin 750 mg once daily for 5 days. 1, 2

Initial Assessment and Diagnosis

• Always obtain urine culture and susceptibility testing before initiating therapy to guide definitive treatment 1, 2
• Consider hospitalization for patients with complicated infections, sepsis, persistent vomiting, failed outpatient treatment, extremes of age, and other high-risk conditions 1
• Local resistance patterns should guide empiric therapy choices 1, 2

Outpatient Treatment Options

First-Line Therapy

• Oral fluoroquinolones (where local resistance <10%):
  • Ciprofloxacin 500 mg twice daily for 7 days 1, 2
  • Ciprofloxacin 1000 mg extended-release for 7 days 2
  • Levofloxacin 750 mg once daily for 5 days (FDA-approved for acute pyelonephritis) 1, 2, 3

Alternative Options

• If fluoroquinolone resistance exceeds 10%, administer an initial one-time intravenous dose of a long-acting parenteral antimicrobial (such as ceftriaxone 1g) before starting oral therapy 1, 2
• Trimethoprim-sulfamethoxazole (160/800 mg twice daily for 14 days) only if the uropathogen is known to be susceptible 1, 2
• Oral β-lactams are considered less effective than fluoroquinolones for pyelonephritis, but can be used for 10-14 days if necessary (with an initial IV dose of a long-acting parenteral antimicrobial) 1

Inpatient Treatment Options

• Initial intravenous antimicrobial regimens include:
  • Fluoroquinolones 1, 2
  • Extended-spectrum cephalosporins (e.g., ceftriaxone) 1, 2
  • Extended-spectrum penicillins with or without aminoglycosides 2
  • Carbapenems (for suspected multidrug-resistant organisms) 1, 2
• Once the patient can tolerate oral intake, switch to appropriate oral therapy based on culture results 1

Treatment Duration

• Fluoroquinolones: 5-7 days (depending on the specific agent) 1, 2
• Trimethoprim-sulfamethoxazole: 14 days 1, 2
• β-lactams: 10-14 days 1, 2

Special Populations

Patients with Renal Impairment

• Dose adjustment is required for many antibiotics in moderate renal impairment (reduce standard dose by approximately 30-50%) 1
• Aminoglycosides should be used with caution in elderly patients with impaired renal function 1

Diabetic Patients

• Patients with diabetes are more vulnerable to complications from acute pyelonephritis, including renal abscesses and emphysematous pyelonephritis 1
• Up to 50% of diabetic patients may not present with typical flank tenderness, making diagnosis more challenging 1

Monitoring and Follow-up

• If the patient fails to improve within 48-72 hours, obtain imaging (preferably CT scan) to evaluate for complications 1, 4
• Consider repeat urine culture 1-2 weeks after completion of antibiotic therapy 5

Common Pitfalls to Avoid

• Failing to obtain urine cultures before initiating antibiotics 1, 2
• Not considering local resistance patterns when selecting empiric therapy 1, 2
• Using fluoroquinolones empirically in areas with >10% resistance without adding an initial dose of a parenteral agent 1, 2
• Using oral β-lactams as monotherapy without an initial parenteral dose 1
• Using agents like nitrofurantoin or oral fosfomycin for pyelonephritis (not recommended due to insufficient data regarding efficacy) 1
• Delaying appropriate antibiotic therapy, which can lead to complications including renal scarring, hypertension, and end-stage renal disease 1