A female resident of a skilled nursing facility in her late eighties is brought to the eme… — USMLE Step 2 CK

A female resident of a skilled nursing facility in her late eighties is brought to the emergency department for severe nausea, intractable vomiting, and failure to pass flatus or stool over the last 48 hours. Her medical history includes vascular dementia, coronary artery disease, and profound age-related muscle wasting. Vital signs on arrival demonstrate a temperature of 38.1°C (100.6°F), blood pressure of 102/65 mmHg, and heart rate of 115/min.

On examination, the patient is confused and appears deeply uncomfortable. The abdomen is markedly distended with high-pitched, tinkling bowel sounds on auscultation. Palpation of the abdomen elicits generalized tenderness, though there is no involuntary guarding or board-like rigidity. When the physician passively extends and internally rotates her right hip, the patient winces and clutches the medial aspect of her right thigh.

Laboratory analysis is notable for a leukocyte count of 16,800/mm³ and a serum lactate concentration of 4.1 mmol/L. A computed tomography scan of the abdomen and pelvis reveals multiple dilated loops of small bowel measuring up to 4.5 cm in diameter. A discrete transition point is visualized in the right true pelvis, where a segment of the distal ileum extends between the pectineus and external obturator muscles. The wall of this herniated loop is thickened, with surrounding inflammatory stranding.

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

Immediate surgical explorationAnswer
B
Nasogastric tube insertion and serial clinical evaluations
C
Administration of a water-soluble enteral contrast agent
D
Manual bedside reduction of the hernia
E
Broad-spectrum intravenous antimicrobial therapy and supportive care alone

Answer

Immediate surgical exploration

The correct answer is immediate surgical exploration. This patient presents with a small bowel obstruction (SBO) secondary to an incarcerated right obturator hernia, complicated by bowel strangulation. Obturator hernias occur when pelvic contents herniate through the obturator canal, a condition predominantly seen in elderly, multiparous, frail women with significant weight loss (loss of the protective preperitoneal fat pad). The classic clinical manifestation is the Howship-Romberg sign, which is characterized by pain along the medial aspect of the thigh extending to the knee, exacerbated by extension, internal rotation, or abduction of the hip due to compression of the obturator nerve. Furthermore, this patient exhibits systemic signs of profound bowel ischemia, including fever, tachycardia, marked leukocytosis, an elevated serum lactate, and bowel wall thickening on computed tomography. Strangulated SBO is an absolute indication for immediate operative intervention (exploratory laparotomy) to resect the ischemic bowel and repair the defect, regardless of the patient's age or frail baseline status. It is critical to recognize that the absence of classical peritoneal signs, such as board-like rigidity, does not rule out strangulation; these physical exam findings are frequently diminished, masked, or entirely absent in elderly, immunocompromised, or neurologically impaired patients.

Step-by-Step Solution

Identify the primary diagnosis based on the clinical presentation and imaging.

The patient has a small bowel obstruction secondary to a right obturator hernia.

Emesis, obstipation, and dilated bowel loops indicate obstruction. The Howship-Romberg sign (medial thigh pain elicited by hip extension and internal rotation) and CT findings of bowel herniating between the pectineus and external obturator muscles confirm the obturator hernia.

Assess the clinical and radiographic data for life-threatening complications.

The patient has signs of bowel strangulation and ischemia.

The presence of fever, tachycardia, marked leukocytosis, an elevated serum lactate level (4.1 mmol/L), and bowel wall thickening on CT strongly suggest that the incarcerated bowel segment is necrotic or ischemic.

Determine the optimal management strategy based on the complication status.

Emergent operative intervention is mandatory.

Strangulated bowel is a surgical emergency. The absence of classic peritonitis (e.g., board-like rigidity) is common in elderly or demented patients and should not delay immediate surgical exploration for resection of necrotic bowel and defect repair.

Key Concept

Strangulated Small Bowel Obstruction (Obturator Hernia)

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