What are the treatment differences between pyelonephritis and acute cystitis?

Treatment Differences Between Pyelonephritis and Acute Cystitis

The key treatment difference between pyelonephritis and acute cystitis is that pyelonephritis requires longer treatment duration (7-14 days), always requires urine culture before starting therapy, and often needs initial parenteral antibiotics, while uncomplicated cystitis can be treated with short-course oral antibiotics (3-5 days) without routine urine culture. 1, 2

Diagnostic Distinctions

Acute Cystitis

• Lower urinary tract symptoms (dysuria, frequency, urgency)
• Generally normal physical exam except possible suprapubic tenderness
• Absence of fever, flank pain, or systemic symptoms
• Urinalysis showing pyuria (>10 leukocytes/mm³) and bacteriuria

Pyelonephritis

• Flank pain (nearly universal finding)
• Fever (though may be absent early)
• Systemic symptoms (nausea, vomiting, malaise)
• Same urinalysis findings as cystitis, but urine culture is mandatory 1, 3

Treatment Approach

Acute Uncomplicated Cystitis

First-line options (3-5 day regimens):

• Nitrofurantoin monohydrate/macrocrystals 100 mg twice daily for 5 days
• Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days (if local resistance <20%)
• Fosfomycin trometamol 3 g single dose (slightly lower efficacy)

Alternative options:

• β-lactams (amoxicillin-clavulanate, cefdinir, cefaclor, cefpodoxime-proxetil) for 3-7 days
• Fluoroquinolones should be reserved for cases where first-line agents cannot be used

Key points:

• Urine culture not routinely needed before treatment
• No follow-up urine testing needed if symptoms resolve
• Short-course therapy (3-5 days) is effective and preferred 1, 2

Acute Pyelonephritis

Outpatient treatment:

• Oral ciprofloxacin 500 mg twice daily for 7 days (if local fluoroquinolone resistance <10%)
• Extended-release ciprofloxacin 1000 mg daily for 7 days
• Levofloxacin 750 mg daily for 5 days

When fluoroquinolone resistance >10% or severe presentation:

• Initial dose of long-acting parenteral antibiotic (ceftriaxone 1g or aminoglycoside) followed by oral therapy

Inpatient treatment:

• Parenteral antibiotics until clinical improvement
• Options include fluoroquinolones, aminoglycosides, and cephalosporins

Key points:

• Urine culture with susceptibility testing mandatory in all cases
• Longer treatment duration (7-14 days)
• Follow-up evaluation if symptoms don't improve within 48-72 hours 1, 3

Special Considerations

Antibiotic Resistance

• Local resistance patterns should guide empiric therapy
• For pyelonephritis, if fluoroquinolone resistance exceeds 10%, initial parenteral dose of broad-spectrum antibiotic recommended
• For cystitis, avoid trimethoprim-sulfamethoxazole if local resistance exceeds 20% 1, 4

Treatment Failure

• For cystitis: If symptoms persist or recur within 2 weeks, obtain urine culture and consider 7-day treatment with alternative agent
• For pyelonephritis: If no improvement within 48-72 hours, imaging (usually CT) and repeat cultures are indicated 2, 3

High-Risk Populations

• Pregnant women with pyelonephritis require admission and initial parenteral therapy
• Patients with sepsis or risk for multidrug-resistant organisms need broader coverage
• Urinary tract obstruction with pyelonephritis requires urgent decompression 3

Common Pitfalls to Avoid

1. Using fluoroquinolones as first-line for uncomplicated cystitis
2. Failing to obtain urine culture before starting antibiotics for pyelonephritis
3. Using too short a treatment course for pyelonephritis
4. Not considering local resistance patterns when selecting empiric therapy
5. Missing concurrent urinary tract obstruction in pyelonephritis patients who don't improve

By understanding these key differences in approach, clinicians can appropriately manage both conditions while minimizing complications and antibiotic resistance.