A 68-year-old woman is evaluated in the hospital for new-onset, severe abdominal pain and … — USMLE Step 2 CK

A 68-year-old woman is evaluated in the hospital for new-onset, severe abdominal pain and distension. She was admitted four days ago for community-acquired pneumonia and has been receiving intravenous ceftriaxone and azithromycin. The patient has not had a bowel movement or passed flatus for the past 24 hours. Her medical history includes type 2 diabetes mellitus, hypertension, and an open total abdominal hysterectomy performed a decade ago. Temperature is $38.6^\circ\text{C}$ ( $101.5^\circ\text{F}$ ), blood pressure is $92/58 \text{ mm Hg}$ , and pulse is $118/\text{min}$ . Physical examination reveals a markedly distended abdomen with diffuse tympany. Palpation elicits severe diffuse tenderness with involuntary guarding and rebound tenderness. Bowel sounds are absent. Laboratory studies show a leukocyte count of $18,500/\text{mm}^3$ and a serum bicarbonate of $15 \text{ mEq/L}$ . A plain radiograph of the abdomen demonstrates multiple dilated loops of small bowel with air-fluid levels and a paucity of gas in the colon. Which of the following is the most appropriate next step in management?

Immediate exploratory laparotomyAnswer
B
Placement of a nasogastric tube and serial clinical observation
C
Abdominopelvic computed tomography with intravenous contrast
D
Intravenous administration of piperacillin-tazobactam and continuation of current care
E
Decompression with flexible sigmoidoscopy

Answer

Immediate exploratory laparotomy is required due to the clinical signs of a strangulated small bowel obstruction.

Exploratory laparotomy is the correct management because this patient presents with a small bowel obstruction complicated by clinical signs of strangulation and ischemia. These signs include peritonitis (involuntary guarding, rebound tenderness), hemodynamic instability, fever, marked leukocytosis, and metabolic acidosis (indicated by low serum bicarbonate). Immediate surgical intervention is necessary to relieve the obstruction and resect any nonviable bowel.

Step-by-Step Solution

Identify the primary pathology from the clinical presentation and radiographic findings.

The patient has a mechanical small bowel obstruction (SBO), likely secondary to adhesions from a prior hysterectomy, evidenced by vomiting, lack of flatus, and dilated small bowel loops on radiography.

Establishing the baseline diagnosis is essential before assessing for complications.

Evaluate for clinical signs of bowel compromise or ischemia.

The patient exhibits fever, tachycardia, hypotension, peritonitis (guarding, rebound tenderness), leukocytosis, and metabolic acidosis.

These specific 'red flag' findings distinguish a simple mechanical obstruction from a strangulated or ischemic obstruction.

Determine the appropriate intervention based on the patient's stability and the presence of complications.

Immediate exploratory laparotomy is indicated.

Strangulated SBO is a surgical emergency; delaying intervention for conservative management or further imaging leads to bowel necrosis, severe sepsis, and death.

Key Concept

Clinical diagnosis and emergency management of strangulated small bowel obstruction.

Estimated Time:1m 30s

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