What is the likely diagnosis and treatment for an elderly woman with a history of kidney stones (nephrolithiasis) presenting with dysuria (burning during urination) and pruritus (itching) during urination, without systemic symptoms such as fever or chills?

Likely Diagnosis and Treatment

This elderly woman most likely has an uncomplicated lower urinary tract infection (cystitis), and should be treated with first-line antibiotics—specifically fosfomycin 3g single dose or nitrofurantoin for 5 days—after confirming she meets diagnostic criteria of dysuria plus at least one additional urinary symptom. 1

Diagnostic Approach

The diagnosis of UTI in elderly patients requires careful clinical assessment because atypical presentations are common. 2

Key diagnostic criteria from the European Association of Urology:

• Antibiotics should ONLY be prescribed if the patient has recent-onset dysuria PLUS at least one of the following: urinary frequency, urgency, new incontinence, systemic signs/symptoms, or costovertebral angle pain/tenderness 1
• This patient presents with dysuria (burning) and pruritus (itching), which together constitute localized urinary symptoms that meet treatment criteria 3
• The absence of fever, chills, and flank pain effectively rules out pyelonephritis or complicated upper tract infection 4

Important consideration regarding her kidney stone history:

• While nephrolithiasis can predispose to UTI through urinary stasis or obstruction, the absence of flank pain makes acute obstruction or infection stone unlikely 5
• Her presentation is consistent with uncomplicated lower UTI rather than stone-related complications 5

Critical Diagnostic Pitfall to Avoid

Do not rely solely on urine dipstick results in elderly patients. 1, 3

• Dipstick specificity is only 20-70% in the elderly 2
• In patients with high pretest probability based on symptoms (like this patient), negative dipstick results do NOT rule out UTI 3
• Classic symptoms of frequency, urgency, and dysuria strongly suggest infection regardless of dipstick results 6

Recommended First-Line Treatment

Obtain urine culture before initiating antibiotics to guide targeted therapy if initial treatment fails, particularly important in elderly patients with higher rates of resistant organisms. 1, 7

First-line antibiotic options (in order of preference):

1. Fosfomycin 3g single dose 1, 6

   • Optimal choice for elderly patients, especially those with any degree of renal impairment 1
   • Maintains therapeutic urinary concentrations regardless of renal function 1
   • No dose adjustment needed 1
   • Low resistance rates 6

2. Nitrofurantoin 100mg twice daily for 5 days 6, 7

   • Effective against most uropathogens with low resistance rates 6, 3
   • AVOID if creatinine clearance <30-60 mL/min due to inadequate urinary concentrations and increased toxicity risk 1

3. Trimethoprim-sulfamethoxazole (TMP-SMX) for 3 days 6, 7

   • Only if local resistance rates are <20% 1, 6
   • Requires dose adjustment based on renal function 1

Antibiotics to AVOID in elderly patients:

• Fluoroquinolones should be avoided unless all other options are exhausted due to increased risk of tendon rupture, CNS effects, QT prolongation, and adverse effects in elderly 1, 6
• Particularly avoid if used in the last 6 months or if local resistance >10% 1

Special Considerations for Elderly Patients

Assess renal function before prescribing:

• Renal function declines by approximately 40% by age 70 1
• Calculate creatinine clearance using Cockcroft-Gault equation to guide medication dosing 1
• This is particularly important given her history of kidney stones, which may affect renal function 5

Review for polypharmacy concerns:

• Check all current medications for potential drug interactions 1, 6
• Avoid coadministration of nephrotoxic drugs with UTI treatment 1

Monitor for clinical improvement:

• Reassess within 48-72 hours for decreased frequency, urgency, and dysuria 6
• Adjust treatment based on culture results if no improvement 6

What NOT to Do

Do NOT treat if this were asymptomatic bacteriuria:

• Asymptomatic bacteriuria occurs in 40% of institutionalized elderly and 15-50% of community-dwelling elderly women 1
• It causes neither morbidity nor increased mortality and should never be treated 1, 4
• Treatment only promotes antibiotic resistance without clinical benefit 8

Do NOT use phenazopyridine routinely for symptomatic relief:

• While it can provide relief for severe dysuria, the decline in renal function associated with advanced age must be considered 9
• If used, limit to 2 days maximum 1
• Patients should be warned about reddish-orange urine discoloration 9