What is the best course of action for an elderly woman with a history of kidney stones, presenting with abrupt onset of urinary urgency, dysuria, and pruritus?

Management of Abrupt Urinary Urgency, Dysuria, and Pruritus in an Elderly Woman with Kidney Stone History

This elderly woman requires immediate antibiotic treatment for acute uncomplicated cystitis, with fosfomycin 3g single dose as the optimal first-line choice given her age, kidney stone history, and potential renal function concerns. 1

Diagnostic Confirmation

The combination of abrupt-onset dysuria, urgency, and irritation (pruritus/burning) meets the European Association of Urology's diagnostic criteria for prescribing antibiotics in elderly patients: recent-onset dysuria PLUS urinary frequency/urgency. 2, 1 These classic symptoms strongly indicate UTI regardless of dipstick results, which have only 20-70% specificity in elderly patients. 2, 1

Key diagnostic points:

• Dysuria with urgency and frequency constitutes sufficient evidence to initiate treatment without waiting for culture results 1, 3
• Negative dipstick results do NOT rule out UTI when typical symptoms are present in high-probability patients 1, 3
• Obtain urine culture before starting antibiotics to guide therapy if initial treatment fails 1, 4

First-Line Antibiotic Selection

Fosfomycin trometamol 3g single dose is the optimal choice for this patient because it:

• Maintains therapeutic urinary concentrations regardless of renal function (critical given her kidney stone history) 1
• Requires no dose adjustment for renal impairment 1
• Has low resistance rates and excellent safety profile in elderly patients 2, 1
• Offers convenient single-dose administration improving compliance 1

Alternative first-line options if fosfomycin unavailable:

• Nitrofurantoin (avoid if creatinine clearance <30-60 mL/min due to inadequate urinary concentrations and toxicity risk) 1, 4
• Trimethoprim-sulfamethoxazole for 3 days (only if local resistance <20% and renal function allows dose adjustment) 2, 1

Critical Pitfalls to Avoid

Do NOT use fluoroquinolones as first-line therapy in this elderly patient due to increased risk of tendon rupture, CNS effects, QT prolongation, and ecological concerns—reserve only if all other options exhausted. 2, 1, 4

Assess renal function immediately given her kidney stone history, as approximately 40% decline occurs by age 70, requiring dosage adjustments for renally-eliminated drugs. 1

Do NOT treat if she has asymptomatic bacteriuria (bacteriuria without these acute symptoms), which occurs in 40% of institutionalized elderly and causes no morbidity or mortality. 2, 1

Imaging Considerations

Evaluate the upper urinary tract with ultrasound to rule out urinary obstruction or active stone disease, particularly given her history of kidney stones, as this could represent complicated rather than uncomplicated UTI. 2 Prompt differentiation is crucial as obstructive pyelonephritis can rapidly progress to urosepsis. 2

Follow-Up and Monitoring

Monitor for clinical improvement within 48-72 hours:

• Decreased frequency, urgency, and dysuria should occur 4
• If symptoms persist or worsen, adjust therapy based on culture results 1, 4
• If fever, rigors, costovertebral angle tenderness, or confusion develop, this indicates progression to pyelonephritis or systemic infection requiring urgent reassessment 2, 5

Recheck renal function in 48-72 hours after initiating treatment to assess for any deterioration, especially important given her kidney stone history. 1