Diagnosis: Acute Uncomplicated Cystitis
This presentation of dysuria, suprapubic discomfort, and urinalysis showing hematuria with ketonuria is consistent with acute uncomplicated cystitis, and you should initiate empiric antibiotic therapy immediately without waiting for urine culture results in this otherwise healthy adult.
Clinical Diagnosis
The combination of dysuria and suprapubic pain has >90% accuracy for diagnosing UTI in women when vaginal discharge is absent, making this a clinical diagnosis that does not require laboratory confirmation before treatment. 1, 2
Hematuria accompanying acute UTI symptoms (dysuria, frequency, urgency, suprapubic pain) is a typical finding in uncomplicated cystitis and does not require imaging or urologic referral in patients <35 years without malignancy risk factors. 3
Ketonuria is not a marker of infection but rather reflects metabolic state (dehydration, fasting, or decreased oral intake due to discomfort); it does not change the diagnosis or management of UTI. 3
When to Order Urine Culture
Urine culture is NOT necessary for typical uncomplicated cystitis in healthy nonpregnant patients with classic symptoms and no risk factors for resistance. 4
Reserve urine culture for: recurrent UTI (≥2 episodes in 6 months or ≥3 in 12 months), treatment failure, history of resistant organisms, atypical presentation, pregnancy, or suspected pyelonephritis. 4, 5
In this straightforward presentation, empiric therapy without culture is appropriate and cost-effective. 4, 5
First-Line Antibiotic Selection
Preferred Option
- Nitrofurantoin 100 mg orally twice daily for 5–7 days is the preferred first-line agent because resistance rates remain <5%, urinary concentrations are high, and disruption of gut flora is minimal. 3, 5
Alternative Options
Fosfomycin 3 g as a single oral dose is an excellent alternative when adherence to a multi-day regimen is a concern. 3, 5
Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days may be used ONLY if local E. coli resistance is <20% and the patient has had no recent exposure to this drug class. 3, 5
Avoid as First-Line
- Fluoroquinolones (ciprofloxacin, levofloxacin) should be reserved for second-line therapy because of rising resistance, serious adverse effects (tendon rupture, peripheral neuropathy, QT prolongation), and substantial microbiome disruption. 3, 6
Red Flags Requiring Different Management
Signs of Pyelonephritis (Complicated UTI)
Fever >38.3°C (101°F), flank pain, costovertebral angle tenderness, nausea/vomiting, or inability to tolerate oral intake indicate upper tract involvement requiring 7–14 days of therapy and mandatory urine culture. 4, 7
If any systemic signs are present, obtain urine culture before starting antibiotics and consider fluoroquinolone therapy for 7–10 days. 3, 5
Risk Factors for Complicated UTI
- Male gender, pregnancy, diabetes, immunosuppression, catheter use, recent urologic instrumentation, or anatomical abnormalities convert this to a complicated UTI requiring culture and longer treatment duration (7–14 days). 4, 7
Follow-Up and Reassessment
Reassess clinical response within 48–72 hours; if symptoms persist or worsen, obtain urine culture and consider imaging to rule out obstruction, stones, or abscess. 3, 5
No routine follow-up urinalysis or culture is needed for uncomplicated cystitis that resolves clinically. 3, 5
If symptoms recur within 2 weeks with the same organism, obtain culture and prescribe a 7-day course of a different antibiotic, assuming resistance to the initial agent. 3, 8
Critical Pitfalls to Avoid
Do not delay treatment waiting for culture results in straightforward uncomplicated cystitis—empiric therapy is appropriate and effective. 4, 5
Do not prescribe nitrofurantoin for <5 days; courses shorter than 5 days have higher failure rates. 3, 5
Do not treat asymptomatic bacteriuria if discovered incidentally; it occurs in 15–50% of older adults and provides no benefit when treated. 4, 3
Hematuria that persists beyond 6 weeks after UTI treatment warrants urologic evaluation (CT urography, cystoscopy) to exclude malignancy or urolithiasis, especially in patients ≥35 years or with malignancy risk factors. 3