What is the first step in diagnosing small bowel obstruction (SBO)?

• A. CT scan of the abdomen
• B. Abdominal ultrasound
• C. Abdominal X-ray
• D. Gastric endoscopy

Answer: (C)

The initial step in diagnosing small bowel obstruction (SBO) is typically an abdominal X-ray. This imaging modality is frequently utilized because it is readily available, quick to perform, and can effectively show the presence of air-fluid levels and distended bowel loops, which are key indicators of an obstruction.

Abdominal X-rays can help differentiate between complete and partial obstructions and provide a preliminary assessment of the cause, such as hernias or tumors. This information is crucial for determining the necessary subsequent steps in management or further imaging.

While CT scans offer more detailed imaging and can be very useful in complex cases of SBO, they are typically reserved for cases where the diagnosis is uncertain after an initial X-ray. Similarly, abdominal ultrasound can be beneficial, especially in children or pregnant women, but it is not the standard first-line investigation for adults. Gastric endoscopy is unrelated to diagnosing SBO, as it focuses on the upper gastrointestinal tract. Therefore, the abdominal X-ray remains the first appropriate choice in the diagnostic pathway for small bowel obstruction.