During an afternoon evaluation, the surgical team examines a 54-year-old woman who underwe… — USMLE Step 2 CK

During an afternoon evaluation, the surgical team examines a $54$ -year-old woman who underwent a laparoscopic Roux-en-Y gastric bypass $6$ days ago. The patient reports the recent onset of severe, unremitting left upper quadrant abdominal pain that radiates to her left shoulder. She has experienced significant nausea but no vomiting. Her temperature is $38.9^\circ\text{C}$ ( $102.0^\circ\text{F}$ ), blood pressure is $112/70\text{ mmHg}$ , pulse is $118/\text{min}$ , and respiratory rate is $22/\text{min}$ . Oxygen saturation is $96\%$ on room air. Physical examination reveals focal peritonitis in the left upper quadrant with voluntary guarding. The surgical incisions are well-approximated, clean, and dry. Bowel sounds are absent. A urinary catheter is in place, draining clear yellow urine. Which of the following is the most appropriate next step in the management of this patient?

Computed tomography of the abdomen with oral contrastAnswer
B
Urinalysis and urine culture
C
Empiric administration of broad-spectrum intravenous antibiotics
D
Chest radiography and incentive spirometry
E
Placement of a nasogastric tube and serial abdominal examinations

Answer

Computed tomography of the abdomen with oral contrast

The patient's clinical presentation of fever, tachycardia, and left upper quadrant pain radiating to the left shoulder (Kehr sign) on postoperative day

6

following a gastric bypass is highly suspicious for an anastomotic leak. The leaked gastrointestinal contents cause peritonitis and diaphragmatic irritation. In a hemodynamically stable patient, the most appropriate next step is imaging with a computed tomography (CT) scan of the abdomen using oral contrast to confirm the diagnosis, identify the location, and evaluate the size of the leak or associated abscess before proceeding to operative or percutaneous intervention.

Step-by-Step Solution

Analyze the timing of the fever and the patient's specific localized symptoms.

Fever on postoperative day 6 combined with tachycardia, left upper quadrant pain, and referred left shoulder pain.

Establishing the timeline and localizing signs narrows the differential diagnosis of postoperative fever away from early causes (like atelectasis) to later causes such as intra-abdominal abscess or anastomotic leak.

Identify the underlying anatomical structure affected.

The left shoulder pain indicates diaphragmatic irritation (Kehr sign), likely from fluid or gastrointestinal contents leaking from the gastrojejunal anastomosis.

Recognizing Kehr sign helps pinpoint the source of the peritonitis in a patient following gastric bypass surgery.

Determine the optimal diagnostic modality to confirm the clinical suspicion.

Select computed tomography (CT) with oral contrast.

Oral contrast will extravasate if a leak is present, confirming the diagnosis and identifying the exact location and extent of fluid collections to plan for intervention.

Key Concept

Diagnosis and management of postoperative anastomotic leak

Estimated Time:1m 15s

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