MCQ – 71133

A 69-year-old man with good past health complained of colicky abdominal pain, increasing abdominal distension, vomiting, and constipation. On general examination, he was afebrile, dehydrated and tachycardia. Abdominal examination showed a distended abdomen with visible peristalsis, and there was generalized abdominal tenderness but no mass could be palpated. Auscultation revealed tinkling and accentuated bowel sounds. There was no abdominal scar to indicate previous surgery. Laboratory investigations showed slightly elevated urea (probably related to dehydration) but were otherwise normal. A supine abdominal radiograph of this patient was performed. What can be the most probable diagnosis?

A.	Acute Appendicitis
B.	Small Bowel Obstruction
C.	Large Bowel Obstruction
D.	Peptic Ulcer

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Correct Answer � B Explanation

Ans:B.)Small Bowel Obstruction.

Image shows:

• Supine abdominal radiograph showing multiple dilated small bowel loops in small bowel obstruction.
• Note the concentric linear ‘bands’ running through the bowel wall: valvulae conniventes, and the LUQ location, suggest that these are dilated jejunal loops.

SMALL BOWEL OBSTRUCTION

• Central colicky abdominal pain is a classic presentation of small bowel obstruction. When the peristaltic waves hit an obstruction producing pain.
• The causes of SBO are myriad, but can be largely divided into mural lesions (e.g. tumor, stricture due to Crohn’s disease, irradiation), luminal (bezoar, gallstone, Ascaris lumbricoides bolus, intussusception) and extrinsic (adhesions, hernia, volvulus, abdominal malignancy)and the most likely etiology is adhesional.
• Examination-
• High-pitched bowel sounds are heard during the early stages of mechanical intestinal obstruction on auscultation.
• The presence of rebound tenderness indicates underlying peritoneal inflammation.
• Plain abdominal films are usually the primary investigation in suspected obstruction.
• Dilated loops of the small bowel are readily identified if they are gas-filled on the supine radiograph. The “string of beads sign”, caused by a line of gas bubbles trapped between the valvulae conniventes, is seen only when the very dilated small bowel is almost completely filled with fluid and is virtually diagnostic of SBO.

• On an AXR it is important to differentiate small bowel and large bowel dilatation.