A 42-year-old woman is brought to the emergency department due to a 6-hour history of acut… — USMLE Step 2 CK

A 42-year-old woman is brought to the emergency department due to a 6-hour history of acute-onset, severe, colicky periumbilical pain that radiates to her back. She also reports multiple episodes of bilious vomiting. Her medical history is significant for morbid obesity treated with a laparoscopic Roux-en-Y gastric bypass 4 years ago, after which she lost 45 kg (100 lb). Current medications include a multivitamin and calcium supplementation. Her temperature is 37.1°C (98.8°F), blood pressure is 105/65 mm Hg, pulse is 118/min, and respirations are 20/min. Physical examination reveals a non-distended, soft abdomen with moderate periumbilical tenderness. There is no rebound tenderness or involuntary guarding. Bowel sounds are hyperactive. Laboratory studies show a leukocyte count of 12,500/mm³ and serum lactate of 2.1 mmol/L. A CT scan of the abdomen and pelvis with intravenous contrast demonstrates a cluster of dilated small bowel segments in the left upper quadrant, stretching and engorgement of the mesenteric vessels, and a small amount of interloop free fluid. Which of the following is the most appropriate next step in management of this patient?

A
Diagnostic upper gastrointestinal endoscopy
B
Nasogastric tube decompression and intravenous fluids
Urgent surgical explorationCevap
D
Oral administration of water-soluble contrast
E
Intravenous broad-spectrum antibiotic therapy and observation

Cevap

Urgent surgical exploration is the most appropriate next step in management.

The correct action is urgent surgical exploration. This patient presents with a classic presentation of an internal hernia following a laparoscopic Roux-en-Y gastric bypass. During a gastric bypass, artificial mesenteric defects are created (e.g., Petersen's space, the mesojejunal defect). Weight loss subsequently decreases mesenteric fat, widening these defects and allowing small bowel loops to herniate through them. This creates a closed-loop obstruction, meaning the bowel is obstructed at two distinct points. This rapidly cuts off venous outflow and arterial supply, leading to ischemia and necrosis. Importantly, patients often lack classic peritoneal signs (guarding, rebound) early in the course because the strangulated bowel is located deep within the abdominal cavity or retroperitoneum. The presence of severe pain, tachycardia, mild lactic acidosis, and CT evidence of clustered loops and engorged vessels (suggesting impending vascular compromise) mandates immediate surgical exploration to reduce the hernia and resect any necrotic bowel.

Adım Adım Çözüm

Analyze the patient's surgical history and current symptoms.

The patient has a history of Roux-en-Y gastric bypass presenting with acute, severe, out-of-proportion abdominal pain and vomiting.

Recognizing the altered anatomy is critical because it predisposes patients to specific late complications, most notably internal hernias (e.g., through Petersen's space or the mesenteric defect).

Evaluate the objective findings (vitals, physical exam, labs, imaging).

Tachycardia, borderline elevated lactate, and CT showing clustered small bowel loops with engorged mesenteric vessels indicate a closed-loop small bowel obstruction.

A closed-loop obstruction involves a segment of bowel trapped at two points, rapidly compromising its vascular supply. Lack of peritonitis is a common pitfall, as ischemic bowel may be shielded deep in the retroperitoneum.

Determine the optimal management strategy.

Select immediate surgical exploration over conservative management.

Internal hernias post-gastric bypass carry a high mortality rate if strangulation occurs. Conservative measures like nasogastric tubes cannot reach the affected bowel segments, mandating urgent operative intervention.

Anahtar Kavram

Internal hernia is a life-threatening complication of Roux-en-Y gastric bypass that presents as a closed-loop small bowel obstruction. It requires high clinical suspicion and urgent surgical exploration, as conservative management is ineffective and delays definitive care.

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