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Difficulty: EasyInfectious Diseases

A 24-year-old woman presents to the university health clinic reporting two days of severe burning upon urination and a sensation of needing to urinate frequently. She denies any fever, chills, flank pain, nausea, or vaginal discharge. Her medical history is unremarkable, and she takes no daily medications other than an oral contraceptive pill. Vital signs include a temperature of 37.1°C (98.8°F), blood pressure of 118/76 mmHg, and a heart rate of 78/min. Physical examination reveals mild suprapubic tenderness but no costovertebral angle tenderness. A clean-catch urinalysis is positive for leukocyte esterase and nitrites, with >50 white blood cells per high-power field. A urine culture is pending. Which of the following is the most appropriate empiric pharmacotherapy for this patient?

  1. Oral nitrofurantoinAnswer
  2. B
    Oral ciprofloxacin
  3. C
    Intramuscular ceftriaxone
  4. D
    Oral moxifloxacin
  5. E
    Oral amoxicillin

Answer

Oral nitrofurantoin
This patient is presenting with acute uncomplicated cystitis, characterized by dysuria, urinary frequency, and suprapubic pain in the absence of systemic symptoms (fever, chills) or upper urinary tract signs (costovertebral angle tenderness). First-line empiric therapy for uncomplicated cystitis includes oral nitrofurantoin, trimethoprim-sulfamethoxazole (TMP-SMX), or a single dose of fosfomycin. Nitrofurantoin is an optimal choice because it concentrates highly in the lower urinary tract and maintains a very low prevalence of bacterial resistance among common uropathogens like Escherichia coli.

Step-by-Step Solution

1
Identify the clinical syndrome based on the patient's presentation.
The patient has dysuria, urinary frequency, suprapubic tenderness, and a positive urinalysis without fever or flank pain, establishing a diagnosis of acute uncomplicated cystitis.
Differentiating uncomplicated cystitis from complicated urinary tract infections or acute pyelonephritis is essential for selecting the appropriate antibiotic class and route.
2
Select the optimal empiric antibiotic therapy according to current stewardship guidelines.
Oral nitrofurantoin, trimethoprim-sulfamethoxazole, or fosfomycin are the preferred first-line agents.
These agents offer narrow, targeted coverage for common uropathogens (like E. coli) while minimizing collateral damage to the normal flora and preserving broad-spectrum antibiotics for severe infections.

Key Concept

Empiric treatment of acute uncomplicated cystitis and principles of antimicrobial stewardship.
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Topics

Infectious Diseases

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