What are the symptoms and treatment options for Pyelonephritis (kidney infection)?

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Last updated: March 25, 2025 • View editorial policy

From the Guidelines

Pyelonephritis, a kidney infection, requires prompt medical attention and treatment with antibiotics such as ciprofloxacin (500mg twice daily) or levofloxacin (750mg once daily) for 7-5 days, respectively, depending on severity and local resistance patterns, as recommended by the European Association of Urology guidelines 1. The symptoms of pyelonephritis include high fever, severe pain, vomiting, and inability to keep fluids down. While waiting for medical care, it is essential to drink plenty of water (2-3 liters daily), take over-the-counter pain relievers like acetaminophen (up to 1000mg every 6 hours, not exceeding 4000mg daily), and apply a heating pad to the abdomen or back for comfort. Key considerations for treatment include:

  • The choice of antibiotic should be based on local resistance patterns and the severity of illness at presentation, as well as specific host factors such as allergies 2, 3.
  • Fluoroquinolone resistance should be less than 10% for empirical oral antimicrobial therapy, and an initial intravenous dose of a long-acting parenteral antimicrobial (e.g., ceftriaxone) should be administered if such agents are used empirically 1.
  • The duration of therapy should be 7-14 days, depending on the severity of the infection and the antibiotic used, with a 5-7 day regimen of a once-daily fluoroquinolone being effective for mild to moderate pyelonephritis 3. It is crucial to seek immediate medical attention if symptoms worsen or do not improve with treatment, and to complete the full antibiotic course even if symptoms improve to prevent complications and promote recovery 2, 3, 1.

From the Research

Symptoms of Pyelonephritis

  • Flank pain
  • Fever
  • Back pain/costovertebral angle tenderness
  • Dysuria
  • Frequency and/or urgency
  • Pyuria (presence of pus in the urine)

Treatment Options for Pyelonephritis

  • Outpatient oral antibiotic therapy with a fluoroquinolone (e.g. ciprofloxacin) or trimethoprim/sulfamethoxazole for mild uncomplicated pyelonephritis 4, 5, 6, 7
  • Injectable third-generation cephalosporins (e.g. ceftriaxone) for patients who require intravenous therapy 4, 5
  • Aminoglycosides as an alternative, but with caution due to potential serious side effects 4
  • Parenteral antibiotic therapy for patients admitted to the hospital, with consideration of antibiotics with activity against extended-spectrum beta-lactamase-producing organisms for those with sepsis or risk of infection with a multidrug-resistant organism 6
  • Treatment duration is typically 7-14 days, with urine culture repeated 1-2 weeks after completion of antibiotic therapy 5, 7

Considerations for Treatment

  • Local resistance patterns should be taken into account when selecting empirical antibiotic therapy 4, 6
  • Antimicrobial susceptibility testing should be performed to guide therapy 4, 5, 6
  • Patients with complicated infections, sepsis, or underlying anatomic/functional abnormalities may require alternative treatment approaches 5, 6
  • Pregnant patients with pyelonephritis should be admitted and treated initially with parenteral therapy due to increased risk of severe complications 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.