A 62-year-old man is evaluated in the emergency department for severe abdominal pain and r… — USMLE Step 2 CK

A $62$ -year-old man is evaluated in the emergency department for severe abdominal pain and recurrent vomiting. Over the past $48$ hours, he experienced crampy, intermittent periumbilical pain, but it abruptly changed to a severe, unremitting ache $4$ hours ago. His last bowel movement was $3$ days ago, and he has not passed flatus since the symptoms began. His surgical history is notable for an appendectomy via a lower midline incision $20$ years ago. Temperature is $38.9^\circ\text{C}$ ( $102.0^\circ\text{F}$ ), pulse is $124/\text{min}$ , respirations are $22/\text{min}$ , and blood pressure is $96/60\text{ mmHg}$ . Physical examination reveals a markedly distended abdomen. Bowel sounds are absent. There is diffuse rigidity, and severe focal tenderness with involuntary guarding is elicited in the mid-abdomen. Laboratory studies reveal a leukocyte count of $18,500/\text{mm}^3$ with $12\%$ bands. Venous blood gas shows a pH of $7.28$ and a bicarbonate level of $15\text{ mEq/L}$ . Which of the following is the most appropriate next step in management?

Urgent exploratory laparotomyAnswer
B
Insertion of a nasogastric tube and continuous suction
C
Computed tomography of the abdomen and pelvis with enteral contrast
D
Intravenous administration of broad-spectrum antibiotics and close observation
E
Water-soluble contrast enema study

Answer

Urgent exploratory laparotomy

The correct action is to perform an urgent exploratory laparotomy. This patient's presentation is highly concerning for a complicated small bowel obstruction (SBO) that has progressed to strangulation or ischemia. The classic triad of simple SBO includes colicky abdominal pain, vomiting, and obstipation. However, the abrupt transition to severe, unremitting pain, coupled with systemic toxicity (fever, tachycardia, marked leukocytosis with bandemia) and metabolic acidosis (low bicarbonate), strongly points to compromised bowel perfusion and necrosis. Furthermore, the presence of diffuse rigidity and guarding indicates peritonitis. In any patient with suspected SBO who develops an acute surgical abdomen or signs of bowel ischemia, immediate surgical exploration is required. Delaying surgery for conservative management or further imaging significantly increases morbidity and mortality.

Step-by-Step Solution

Analyze the primary clinical presentation.

The patient presents with crampy abdominal pain, vomiting, distension, and obstipation in the setting of prior abdominal surgery, which is classic for a small bowel obstruction (SBO) secondary to adhesions.

Identifying the baseline syndrome is required to evaluate the clinical trajectory and select the appropriate treatment algorithm.

Assess for warning signs of complicated disease.

The pain abruptly transitioned from intermittent to constant and severe. The patient also demonstrates systemic toxicity (fever, tachycardia, severe leukocytosis), metabolic acidosis (low bicarbonate), and peritonitis (rigidity, guarding).

Distinguishing between a simple SBO and a complicated, strangulated SBO dictates the urgency and modality of the intervention.

Determine the optimal intervention.

Because the patient exhibits clear evidence of bowel ischemia or perforation, nonoperative management must be abandoned in favor of immediate surgical exploration.

Delaying source control in the presence of an acute surgical abdomen dramatically increases mortality due to sepsis and progressive multiorgan failure.

Key Concept

Patients with a small bowel obstruction who develop clinical signs of strangulation or ischemia (e.g., continuous severe pain, fever, tachycardia, peritoneal signs, metabolic acidosis, marked leukocytosis) require immediate exploratory laparotomy, bypassing further diagnostic imaging or conservative management.

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