A 54-year-old woman is brought to the emergency department due to severe, generalized abdo… — USMLE Step 2 CK

A $54$ -year-old woman is brought to the emergency department due to severe, generalized abdominal pain and persistent bilious vomiting for the past $12$ hours. She has not passed flatus or stool since yesterday. Her surgical history is significant for a total abdominal hysterectomy $5$ years ago. Temperature is $39.2^\circ\text{C}$ ( $102.6^\circ\text{F}$ ), blood pressure is $90/60\text{ mmHg}$ , and pulse is $122/\text{min}$ . Physical examination reveals a markedly distended abdomen with diffuse guarding, severe rebound tenderness, and absent bowel sounds. Laboratory studies show a leukocyte count of $22,000/\text{mm}^3$ and a serum lactate of $5.1\text{ mmol/L}$ . An upright abdominal radiograph shows multiple dilated loops of small bowel with air-fluid levels and no free air under the diaphragm. Which of the following is the most appropriate next step in management?

Urgent exploratory laparotomyAnswer
B
Nasogastric tube insertion and serial abdominal examinations
C
CT scan of the abdomen and pelvis with intravenous contrast
D
Intravenous administration of broad-spectrum antibiotics and clinical observation
E
Upper gastrointestinal series with small bowel follow-through

Answer

Urgent exploratory laparotomy

The correct answer is urgent exploratory laparotomy. This patient presents with the classic triad of small bowel obstruction (SBO): colicky abdominal pain, vomiting, and obstipation. Her prior hysterectomy makes adhesions the most likely etiology. Furthermore, she has definitive signs of a complicated (strangulated) obstruction, including fever, tachycardia, hypotension, elevated lactate, marked leukocytosis, and peritonitis (diffuse guarding and rebound tenderness). In the setting of an SBO with overt signs of bowel ischemia or peritonitis, the most appropriate next step is immediate surgical exploration to resect necrotic bowel and relieve the obstruction. Any delay for further imaging or conservative management significantly increases mortality.

Step-by-Step Solution

Identify the primary diagnosis based on the clinical presentation.

The patient has bilious vomiting, obstipation, abdominal distension, and air-fluid levels on radiograph, which are classic for a small bowel obstruction (SBO).

Recognizing the core pathology is necessary to direct further workup and management.

Assess the patient for complications of the primary diagnosis.

The patient exhibits fever, tachycardia, hypotension, lactic acidosis, leukocytosis, and diffuse peritonitis (guarding and rebound tenderness), indicating a complicated, likely strangulated, SBO.

Distinguishing between uncomplicated and complicated SBO is the main determinant of the treatment pathway.

Select the appropriate intervention based on the presence of complications.

Because the patient has peritonitis and is hemodynamically unstable, immediate surgical intervention via exploratory laparotomy is required over conservative measures or further diagnostic imaging.

Complicated SBO carries a high risk of bowel necrosis and perforation, making prompt surgical source control life-saving.

Key Concept

Management of Complicated Small Bowel Obstruction

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic