Following a transfer from a long-term care facility, an 82-year-old female patient is eval… — USMLE Step 2 CK

Following a transfer from a long-term care facility, an 82-year-old female patient is evaluated in the hospital for a two-day history of progressive somnolence. Her medical history is significant for advanced Alzheimer dementia and chronic urinary retention requiring an indwelling urethral catheter. Upon presentation, her blood pressure is $112/64\text{ mmHg}$ , heart rate is $96/\text{min}$ , and temperature is $36.9^\circ\text{C}$ ( $98.4^\circ\text{F}$ ). Physical examination reveals dry oral mucosa, diminished skin turgor, and no costovertebral angle tenderness. The patient is lethargic but arouses to voice. Laboratory evaluation reveals a serum sodium concentration of $159\text{ mEq/L}$ and a blood urea nitrogen level of $45\text{ mg/dL}$ . A urinalysis demonstrates cloudy, malodorous urine with positive leukocyte esterase, positive nitrites, and $45\text{ WBCs/hpf}$ . A urine culture is submitted, and she is started on intravenous fluid resuscitation.

By the third day of hospitalization, her serum sodium has corrected to $142\text{ mEq/L}$ , and her mental status has returned to her baseline of being pleasantly confused but conversational. She remains hemodynamically stable and afebrile. The admission urine culture now reports $>10^5\text{ CFU/mL}$ of *Escherichia coli* that is susceptible to all tested antimicrobial agents. Which of the following is the most appropriate next step in the management of this patient's urinary findings?

Observation without targeted antimicrobial therapyCevap
B
Initiate oral trimethoprim-sulfamethoxazole
C
Initiate intravenous ceftriaxone
D
Replace the indwelling catheter and initiate oral ciprofloxacin
E
Perform a renal and bladder ultrasound

Cevap

Observation without targeted antimicrobial therapy

The correct approach is observation without targeted antimicrobial therapy because this patient has asymptomatic bacteriuria. Patients with chronic indwelling urinary catheters almost universally develop bacteriuria and pyuria as a result of biofilm formation and bacterial colonization. A true catheter-associated urinary tract infection (CAUTI) requires both a positive urine culture and new systemic or localizing symptoms (e.g., fever, rigors, flank pain, or acute hematuria) that have no other identified cause. Although this patient initially presented with altered mental status, her delirium was clearly a result of severe hypernatremia and volume depletion, as evidenced by its complete resolution following intravenous hydration. The presence of cloudy, malodorous urine and pyuria are expected findings in catheter colonization and do not warrant antimicrobial therapy. Treating asymptomatic bacteriuria violates the core principles of antibiotic stewardship, as it does not improve clinical outcomes and inappropriately increases the risk of antimicrobial resistance, adverse drug effects, and *Clostridioides difficile* infection.

Adım Adım Çözüm

Identify the etiology of the patient's presenting symptoms.

The initial somnolence was driven by severe hypernatremia and volume depletion, which entirely resolved with intravenous hydration.

Mental status returned to baseline upon normalization of serum sodium, confirming the delirium was metabolic rather than infectious.

Evaluate the clinical significance of the urinalysis and culture results.

The patient has pyuria (

45\text{ WBCs/hpf}

) and bacteriuria (

>10^5\text{ CFU/mL}

of *E. coli*), but lacks any systemic or localizing signs of infection.

In a patient with a chronic indwelling catheter, pyuria and bacteriuria are expected findings of colonization. Without fever, flank pain, or unexplained systemic signs, this represents asymptomatic bacteriuria.

Select the appropriate evidence-based intervention.

Observation without targeted antimicrobial therapy is the indicated management.

Treating asymptomatic bacteriuria does not improve outcomes and increases the risk of adverse drug events and antibiotic resistance.

Anahtar Kavram

Asymptomatic bacteriuria in patients with chronic indwelling urinary catheters does not warrant screening or antimicrobial therapy, even in the presence of pyuria or malodorous urine.

Soru

Cevap

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