What is the recommended treatment for Pylonephritis?

Treatment of Pyelonephritis

For uncomplicated pyelonephritis in outpatients, initiate oral fluoroquinolone therapy with ciprofloxacin 500-750 mg twice daily for 7 days or levofloxacin 750 mg once daily for 5 days, provided local fluoroquinolone resistance is ≤10%. 1, 2

Initial Assessment and Risk Stratification

Immediately determine if the infection is complicated or obstructive, as obstructive pyelonephritis can rapidly progress to urosepsis and requires urgent intervention 1:

• Obtain urine culture and antimicrobial susceptibility testing before starting antibiotics in all cases 1, 2
• Perform urgent upper urinary tract imaging (ultrasound or CT) if frank hematuria is present, symptoms suggest obstruction, or the patient fails to improve within 48-72 hours 1
• Check for complications including urinary tract obstruction, renal abscess, stones, or structural abnormalities—particularly when hematuria is present 1

Outpatient Treatment Algorithm

For mild to moderate uncomplicated pyelonephritis without severe symptoms:

• First-line: Oral ciprofloxacin 500 mg twice daily for 7 days OR levofloxacin 750 mg once daily for 5 days 2, 3
• Consider a single initial IV dose of ceftriaxone 1g or aminoglycoside before starting oral therapy, especially if local fluoroquinolone resistance exceeds 10% 1, 2
• Alternative if fluoroquinolones cannot be used: Trimethoprim-sulfamethoxazole for 14 days, but only if the pathogen is known to be susceptible 1

Critical caveat: β-lactam antibiotics are less effective than fluoroquinolones for pyelonephritis and require longer treatment durations (10-14 days) 2. Never use amoxicillin or ampicillin empirically due to high resistance rates 2.

Inpatient Treatment Algorithm

Hospitalize patients with:

• Severe illness, sepsis, or hemodynamic instability 1
• Persistent vomiting preventing oral intake 4
• Complicated infections (obstruction, abscess, immunocompromised) 1, 2
• Frank hematuria suggesting complicated infection 1
• Failed outpatient treatment 4

Empiric IV therapy options 1:

• Ciprofloxacin 400 mg IV twice daily
• Levofloxacin 750 mg IV once daily
• Ceftriaxone 1-2 g IV once daily
• Cefotaxime 2 g IV three times daily
• Piperacillin/tazobactam 2.5-4.5 g IV three times daily
• Aminoglycoside (gentamicin 5 mg/kg once daily or amikacin 15 mg/kg once daily) with or without ampicillin

Switch to oral therapy when clinically improved, typically using equivalent oral fluoroquinolone dosing 3

Antimicrobial Resistance Considerations

Local resistance patterns must guide empiric therapy selection 1, 2:

• If fluoroquinolone resistance exceeds 10% locally, use initial parenteral broad-spectrum therapy (ceftriaxone or aminoglycoside) before oral fluoroquinolone 1
• Reserve carbapenems for multidrug-resistant organisms only 1
• Tailor therapy immediately once culture and susceptibility results are available 1

Treatment Duration

• Fluoroquinolones: 5-7 days 2
• Trimethoprim-sulfamethoxazole: 14 days 2
• β-lactam antibiotics: 10-14 days 2
• Complicated infections or frank hematuria: May require longer duration based on clinical response 1

Special Considerations for Complicated Cases

Frank hematuria indicates complicated UTI requiring more aggressive management 1:

• Suggests possible obstruction, stones, or structural abnormalities 1
• Requires urgent imaging to rule out surgical emergencies 1
• May necessitate longer treatment duration 1

Mixed urogenital flora often represents contamination, but true polymicrobial infections occur with urinary tract abnormalities, recent instrumentation, indwelling catheters, or immunocompromised status 2. Use broader-spectrum coverage until culture results clarify the situation 2.

Follow-Up

Repeat urine culture 1-2 weeks after completing antibiotic therapy to confirm eradication 4. If treatment fails, obtain repeat blood and urine cultures, consider imaging studies, and evaluate for resistant organisms, anatomic/functional abnormalities, or immunosuppression 4.