From the Guidelines
Pyelonephritis should be diagnosed and treated promptly with a combination of clinical assessment, laboratory tests, and imaging studies, with empiric oral antibiotics like fluoroquinolones or cephalosporins being the recommended initial treatment, as stated in the European Association of Urology guidelines 1. The diagnosis of pyelonephritis typically begins with evaluating symptoms such as flank pain, fever, nausea, and urinary symptoms, followed by urinalysis showing pyuria, bacteriuria, and positive leukocyte esterase. Urine culture identifies the causative organism and guides antibiotic therapy. Blood tests may reveal elevated white blood cell count and inflammatory markers.
Diagnostic Approach
- Urinalysis, including assessment of white and red blood cells and nitrite, is recommended for routine diagnosis 1.
- A urine culture and antimicrobial susceptibility testing should be performed in all cases of pyelonephritis.
- Evaluation of the upper urinary tract via ultrasound should be performed to rule out urinary tract obstruction or renal stone disease in patients with a history of urolithiasis, renal function disturbances or a high urine pH 1.
Treatment Approach
- For uncomplicated pyelonephritis, empiric oral antibiotics like ciprofloxacin (500 mg twice daily for 7 days) or levofloxacin (750 mg daily for 5-7 days) are recommended, as per the European Association of Urology guidelines 1.
- Hospitalization with intravenous antibiotics such as ceftriaxone (1-2 g daily) is necessary for severe cases, pregnant patients, or those with complications.
- Treatment should be adjusted based on culture results and continued for 7-14 days total.
- Patients should increase fluid intake, manage pain with acetaminophen or NSAIDs, and complete the full antibiotic course even if symptoms improve.
- Follow-up urinalysis after treatment completion is recommended to confirm resolution.
Key Considerations
- Prompt differentiation between uncomplicated and potentially obstructive pyelonephritis is crucial, as the latter can swiftly progress to urosepsis.
- The choice of antibiotic should be based on local resistance patterns and optimized, with fluoroquinolones and cephalosporins being the only antimicrobial agents that can be recommended for oral empiric treatment of uncomplicated pyelonephritis 1.
From the FDA Drug Label
Dosing and initial route of therapy (i.e., I.V. or oral) for complicated urinary tract infection or pyelonephritis should be determined by the severity of the infection. In the clinical trial, pediatric patients with moderate to severe infection were initiated on 6 to 10 mg/kg I. V. every 8 hours and allowed to switch to oral therapy (10 to 20 mg/kg every 12 hours), at the discretion of the physician.
The diagnostic and treatment approaches for pyelonephritis involve determining the severity of the infection and choosing the appropriate route of therapy (I.V. or oral) based on that severity.
- Key considerations:
- The initial dose for pediatric patients with moderate to severe infection is 6 to 10 mg/kg I.V. every 8 hours.
- Patients can be switched to oral therapy (10 to 20 mg/kg every 12 hours) at the discretion of the physician.
- The total duration of therapy for complicated urinary tract infection and pyelonephritis can range from 10 to 21 days, with a mean duration of 11 days.
- The decision to switch from I.V. to oral therapy should be based on the clinical judgment of the physician, taking into account the severity of the infection and the patient's response to treatment 2.
From the Research
Diagnostic Approaches for Pyelonephritis
- History and physical examination are the most useful tools for diagnosis, with most patients presenting with fever and flank pain 3
- A positive urinalysis confirms the diagnosis in patients with a compatible history and physical examination 3
- Urine culture should be obtained in all patients to guide antibiotic therapy if the patient does not respond to initial empiric antibiotic regimens 3
- Imaging, usually with contrast-enhanced computed tomography, is not necessary unless there is no improvement in the patient's symptoms or if there is symptom recurrence after initial improvement 3
Treatment Approaches for Pyelonephritis
- Outpatient treatment is appropriate for most patients, with oral fluoroquinolones recommended as initial outpatient therapy if the rate of fluoroquinolone resistance in the community is 10 percent or less 3
- Inpatient therapy is recommended for patients who have severe illness or in whom a complication is suspected 3
- Several antibiotic regimens can be used for inpatient treatment, including fluoroquinolones, aminoglycosides, and cephalosporins 3
- Acute pyelonephritis should be classified clinically at the time of presentation into either uncomplicated or complicated categories, with different treatment approaches for each category 4
- Patients with suspected complicated pyelonephritis require the standard assessment plus blood cultures and urinary tract imaging, preferably a computed tomography (CT) scan 4
Comparison of Antibiotic Regimens
- Ceftriaxone was more effective than levofloxacin in the treatment of acute pyelonephritis, based on microbiological response 5
- There were no statistically significant differences between the treatment groups in the rates of clinical cure 5
- Oral cephalosporins may be considered as an alternative to first-line agents for the treatment of acute pyelonephritis, with no significant difference in UTI recurrence rates between oral cephalosporins and first-line agents 6
- Failure of therapy for pyelonephritis occurred more often in the fluoroquinolone and trimethoprim-sulfamethoxazole group than in the cephalosporin group 7