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Difficulty: HardGastrointestinal and Abdominal Surgery

A 42-year-old man is evaluated on the surgical ward due to a sudden deterioration in his clinical status. He was admitted 24 hours ago for a mechanical small bowel obstruction secondary to adhesions from an appendectomy performed 15 years ago. Initial management included bowel rest, intravenous fluid resuscitation, and nasogastric tube decompression, which produced 800 mL of bilious output. During the last two hours, his previously intermittent, crampy abdominal pain has transitioned into constant, excruciating pain that is unresponsive to intravenous analgesics.

Vital signs currently show a temperature of 38.7°C (101.7°F), blood pressure of 102/64 mm Hg, pulse of 122/min, and respirations of 22/min. Physical examination demonstrates a markedly distended abdomen with diffuse rigidity, involuntary guarding, and severe rebound tenderness. Bowel sounds, which were previously high-pitched, are now absent. A repeat basic metabolic panel reveals a serum bicarbonate of 15 mEq/L, decreased from 24 mEq/L on admission.

Which of the following is the most appropriate next step in the management of this patient?

  1. A
    Computed tomography of the abdomen and pelvis with intravenous contrast
  2. B
    Upper gastrointestinal series with water-soluble contrast
  3. Urgent exploratory laparotomyAnswer
  4. D
    Continued nasogastric decompression and addition of intravenous broad-spectrum antibiotics
  5. E
    Diagnostic laparoscopy

Answer

The most appropriate next step in management is an urgent exploratory laparotomy.
The correct answer is urgent exploratory laparotomy. This patient initially presented with an uncomplicated adhesive small bowel obstruction (SBO) and was appropriately managed with conservative measures. However, he has now developed cardinal signs of a complicated or strangulated SBO. The transition from intermittent, crampy pain to constant, severe pain is a classic indicator of bowel ischemia. Furthermore, the presence of fever, tachycardia, and diffuse peritonitis (rigidity, guarding, rebound tenderness) on examination, combined with a newly developed metabolic acidosis (evidenced by the low bicarbonate), strongly points to bowel necrosis or perforation. In any patient with an SBO who develops hemodynamic instability, peritonitis, or signs of ischemia, conservative management must be immediately discontinued, and an urgent exploratory laparotomy is required to prevent further sepsis and to resect nonviable bowel.

Step-by-Step Solution

1
Analyze the patient's change in clinical symptoms.
The patient's abdominal pain transitioned from intermittent and crampy to constant and excruciating.
This transition is a cardinal clinical symptom indicating compromised bowel perfusion and impending ischemia.
2
Evaluate the vital signs and physical examination findings.
The patient has a fever (38.7°C), tachycardia (122/min), and diffuse peritonitis indicated by rigidity, involuntary guarding, and severe rebound tenderness.
These findings confirm a transition from a simple obstruction to a complicated, strangulated obstruction with localized or generalized peritoneal inflammation.
3
Interpret the laboratory findings.
The serum bicarbonate level dropped significantly from 24 mEq/L to 15 mEq/L.
This decrease suggests the development of a new-onset anion gap metabolic acidosis, likely secondary to lactic acidosis from ischemic and necrotic bowel tissue.
4
Determine the most appropriate next step in management.
The patient must undergo an urgent exploratory laparotomy.
Conservative management and further imaging are strictly contraindicated once clinical signs of strangulation and peritonitis are present, as immediate surgical source control is required to prevent fatal sepsis.

Key Concept

Patients with a small bowel obstruction who develop signs of strangulation (e.g., constant pain, fever, peritonitis, metabolic acidosis) require immediate exploratory laparotomy, and further imaging or conservative management should be abandoned.
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Topics

Gastrointestinal and Abdominal Surgery

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