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Difficulty: Very hardGastrointestinal and Abdominal Surgery

An emaciated 79-year-old woman is evaluated in the emergency department for intractable vomiting and generalized abdominal pain that has progressively worsened over the past 48 hours. She has a long-standing history of anorexia nervosa, and her current body mass index is 15.2 kg/m215.2\text{ kg/m}^2. Temperature is 38.4°C (101.1°F), blood pressure is 86/52 mmHg, pulse is 124/min, and respirations are 22/min. Physical examination reveals a distended abdomen with diffuse guarding and rebound tenderness. No masses are palpable in the bilateral groins or abdominal wall. During the examination, passive extension and medial rotation of her right hip elicits sudden, excruciating pain radiating down the anteromedial aspect of her right thigh. Laboratory studies show a leukocyte count of 16,800/mm316,800/\text{mm}^3 and a serum lactate of 4.9 mmol/L4.9\text{ mmol/L}. An upright abdominal radiograph demonstrates multiple dilated loops of small bowel with prominent air-fluid levels and a paucity of colonic gas. There is no free subdiaphragmatic air. Which of the following is the most appropriate next step in management?

  1. Immediate exploratory laparotomyAnswer
  2. B
    Nasogastric tube decompression and serial abdominal examinations
  3. C
    CT scan of the abdomen and pelvis with intravenous contrast
  4. D
    Right anterior inguinal exploration and tissue repair
  5. E
    Intravenous administration of broad-spectrum antibiotics and observation

Answer

The most appropriate next step is an immediate exploratory laparotomy due to the presence of a strangulated small bowel obstruction (obturator hernia) with peritonitis and hemodynamic instability.
The patient's presentation is highly suspicious for a strangulated small bowel obstruction caused by an incarcerated right obturator hernia. Emaciated elderly women are at the highest risk for this rare hernia due to the loss of the protective preperitoneal fat pad in the obturator canal. The pathognomonic Howship-Romberg sign (pain radiating down the medial thigh exacerbated by hip extension and medial rotation) occurs because the hernia sac compresses the obturator nerve against the pubic bone. Crucially, the presence of generalized peritonitis (guarding, rebound tenderness), hemodynamic instability, leukocytosis, and an elevated serum lactate strongly indicate advanced bowel ischemia and necrosis. The definitive treatment for a strangulated small bowel obstruction with peritonitis is an immediate exploratory laparotomy. This approach allows for reduction of the hernia, assessment of bowel viability, and resection of any necrotic segments. Proceeding directly to the operating room is imperative, as delaying for further imaging would be fatal in this unstable patient.

Step-by-Step Solution

1
Analyze the patient's acute presentation and radiographic findings.
The patient has a mechanical small bowel obstruction characterized by dilated small bowel loops, air-fluid levels, and intractable vomiting.
Identifying the primary syndrome directs the initial surgical triage pathway.
2
Interpret the specific physical exam maneuver and patient demographics.
Pain on passive extension and medial rotation of the hip radiating to the medial thigh is the Howship-Romberg sign. In an emaciated elderly woman, this indicates an incarcerated obturator hernia compressing the obturator nerve.
Obturator hernias are deep pelvic hernias not palpable externally, making specific nerve compression signs vital for clinical diagnosis.
3
Evaluate the patient's physiologic status to determine operative timing.
The presence of fever, tachycardia, hypotension, lactic acidosis, and diffuse peritonitis indicates advanced bowel strangulation and necrosis.
Strangulated bowel rapidly leads to systemic toxicity and requires immediate surgical source control.
4
Select the appropriate intervention based on stability.
Immediate exploratory laparotomy is chosen over further imaging (CT scan) or conservative measures due to the patient's unstable hemodynamics and surgical abdomen.
Delaying surgery for imaging in an unstable patient with a clear indication for exploration increases mortality.

Key Concept

Management of Strangulated Small Bowel Obstruction and Obturator Hernia
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Topics

Gastrointestinal and Abdominal Surgery

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