A 28-year-old woman comes to the outpatient clinic reporting a 4-day history of frequent, … — USMLE Step 2 CK

A $28$ -year-old woman comes to the outpatient clinic reporting a $4$ -day history of frequent, watery stools, accompanied by intermittent periumbilical cramps and mild nausea. She works as a veterinary technician and recently cleaned several reptile enclosures. She has no significant past medical history and takes no medications. Her temperature is $37.4^\circ \text{C}$ ( $99.3^\circ \text{F}$ ), blood pressure is $118/74 \text{ mmHg}$ , and pulse is $84/\text{min}$ . Physical examination shows moist mucous membranes and normal skin turgor. The abdomen is soft and non-tender with hyperactive bowel sounds. Laboratory studies show a leukocyte count of $7,800/\text{mm}^3$ . A stool culture returns positive for non-typhoidal \textit{Salmonella}. Which of the following is the most appropriate next step in management?

A
Intravenous ceftriaxone
B
Oral azithromycin
Observation and oral fluid replacementAnswer
D
Oral ciprofloxacin
E
Oral vancomycin

Answer

Observation and oral fluid replacement

The correct answer is observation and oral fluid replacement. This patient has a classic presentation of non-typhoidal Salmonella gastroenteritis, commonly associated with handling reptiles (e.g., turtles, lizards) or consuming undercooked poultry. In healthy, immunocompetent individuals aged

12

50

years with mild to moderate disease, the infection is self-limiting. Antibiotic therapy is contraindicated in this demographic because it does not significantly shorten the duration of symptoms and actually prolongs asymptomatic fecal shedding of the bacteria. Treatment should focus entirely on supportive care and maintaining hydration.

Step-by-Step Solution

Analyze the patient's clinical presentation and risk factors.

The patient has mild gastroenteritis likely contracted from reptile exposure, with normal vital signs, reassuring physical exam, and no underlying immunocompromising conditions.

Determining disease severity and host immunity status dictates whether antimicrobial intervention is necessary.

Evaluate the stool culture result in the context of the clinical picture.

The culture is positive for non-typhoidal Salmonella.

Specific pathogens have distinct management algorithms based on their natural disease course.

Apply infectious disease guidelines for non-typhoidal Salmonella.

Supportive care (observation and hydration) is selected.

In immunocompetent adults with non-severe disease, antibiotics do not significantly shorten the duration of symptoms and are known to prolong the asymptomatic carrier state (fecal shedding).

Key Concept

Management of acute non-typhoidal Salmonella gastroenteritis

Estimated Time:1m 15s

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