A 55-year-old woman is brought to the emergency department by her husband due to severe, d… — USMLE Step 2 CK

A $55$ -year-old woman is brought to the emergency department by her husband due to severe, diffuse abdominal pain and repetitive vomiting that began $24$ hours ago. She reports that she has not passed gas or had a bowel movement for the past $2$ days. Her medical history is significant for a total abdominal hysterectomy $6$ years ago. Upon arrival, she appears lethargic and is in acute distress. Her temperature is $39.2^{\circ}\text{C}$ ( $102.6^{\circ}\text{F}$ ), pulse is $130/\text{min}$ , respirations are $24/\text{min}$ , and blood pressure is $84/50\text{ mmHg}$ . Physical examination reveals a markedly distended abdomen. Palpation demonstrates diffuse rigidity, involuntary guarding, and severe rebound tenderness. Bowel sounds are absent. Laboratory studies show a leukocyte count of $18,500/\text{mm}^3$ with $85\%$ neutrophils. An upright abdominal radiograph shows 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 the management of this patient?

Immediate exploratory laparotomyAnswer
B
Placement of a nasogastric tube and serial abdominal examinations
C
Computed tomography scan of the abdomen with intravenous contrast
D
Initiation of intravenous broad-spectrum antibiotics and medical observation
E
Measurement of serum brain natriuretic peptide and echocardiography

Answer

The most appropriate next step is immediate exploratory laparotomy due to the presence of a strangulated small bowel obstruction complicated by peritonitis and shock.

The correct answer is immediate exploratory laparotomy. This patient presents with classic features of a small bowel obstruction (SBO), likely secondary to adhesions from her prior hysterectomy. While many cases of SBO can be managed conservatively with bowel rest and nasogastric decompression, this patient exhibits 'red flag' signs of strangulation and bowel ischemia. These include a high fever (

39.2^{\circ}\text{C}

), marked leukocytosis (

18,500/\text{mm}^3

), hemodynamic instability (blood pressure

84/50\text{ mmHg}

), and a rigid abdomen with severe rebound tenderness (peritonitis). When an acute surgical abdomen is clearly identified alongside systemic toxicity, the absolute next best step is prompt surgical exploration to resect necrotic tissue and relieve the obstruction. Delays in surgery dramatically increase morbidity and mortality.

Step-by-Step Solution

Identify the primary diagnosis based on the history and initial imaging.

The patient's history of prior abdominal surgery, absence of flatus, vomiting, and radiographic evidence of dilated loops with air-fluid levels confirm a small bowel obstruction.

Establishing the underlying anatomic problem is the first step in evaluating acute abdominal pain.

Assess for complications of the obstruction.

The physical examination shows diffuse rigidity and rebound tenderness. Vitals reveal fever, tachycardia, and hypotension, accompanied by profound leukocytosis.

These findings differentiate a simple, uncomplicated obstruction from a strangulated or ischemic bowel, which dictates the urgency of intervention.

Determine the appropriate clinical intervention.

The patient must be taken directly to the operating room for an immediate exploratory laparotomy.

Ischemic or necrotic bowel is a surgical emergency; delaying for conservative measures or advanced imaging significantly increases mortality.

Key Concept

Emergent surgical management is required for small bowel obstructions that present with signs of clinical deterioration, such as peritonitis, hemodynamic instability, or severe systemic inflammatory response.

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