From the Guidelines
Pyelonephritis is primarily caused by bacterial infections, most commonly Escherichia coli (E. coli), and the primary treatment involves antibiotics, with the specific regimen depending on severity, as recommended by the European Association of Urology guidelines 1.
Causes of Pyelonephritis
The infection typically occurs when bacteria overcome the urinary tract's natural defenses, with risk factors including:
- Female anatomy
- Sexual activity
- Urinary tract abnormalities
- Compromised immune systems
Treatment of Pyelonephritis
For uncomplicated cases, oral fluoroquinolones like ciprofloxacin (500mg twice daily for 7 days) or trimethoprim-sulfamethoxazole (160/800mg twice daily for 14 days) are typically effective 1. Severe or complicated cases require hospitalization and intravenous antibiotics such as ceftriaxone (1-2g daily) or ampicillin plus gentamicin, followed by oral antibiotics for a total 10-14 day course 1.
Additional Recommendations
Patients should increase fluid intake to help flush bacteria from the urinary system and take pain relievers like acetaminophen for fever and discomfort. Symptoms typically improve within 48-72 hours of starting antibiotics, but completing the full course is essential to prevent recurrence and antibiotic resistance 1. Key considerations in the management of pyelonephritis include prompt differentiation between uncomplicated and potentially obstructive pyelonephritis, as the latter can swiftly progress to urosepsis, and the use of imaging techniques such as ultrasound or MRI to evaluate the upper urinary tract and rule out urinary tract obstruction or renal stone disease 1.
From the Research
Causes of Pyelonephritis
- The primary cause of pyelonephritis is a bacterial infection, with Escherichia coli being the most prevalent uropathogen 2, 3, 4.
- Other common causes of pyelonephritis include Klebsiella pneumoniae, Proteus, and Staphylococcus saprophyticus 3, 4.
- The infection can occur through the ascent of bacteria from the lower urinary tract or through hematogenous spread 5.
Risk Factors
- Urinary catheterization is a significant risk factor for pyelonephritis, particularly for Klebsiella pneumoniae infections 4.
- Neurogenic bladder, obstructive uropathy, urinary tract stones, and bacteremia are also associated with an increased risk of pyelonephritis 4.
- Pregnancy is a significant risk factor for severe complications from pyelonephritis 5.
Treatment
- Antibiotic therapy is the primary treatment for pyelonephritis, with the choice of antibiotic depending on the causative organism and local resistance patterns 2, 5, 3.
- Fluoroquinolones and trimethoprim/sulfamethoxazole are effective oral antibiotics for most cases, but increasing resistance makes empiric use problematic 5.
- Parenteral antibiotic therapy is recommended for patients admitted to the hospital, particularly those with sepsis or risk of infection with a multidrug-resistant organism 5.
- The duration of treatment varies from 7 to 14 days, depending on the severity of the infection and the patient's response to treatment 3, 6.