Intestinal Obstruction — SAQ

Stem

A 58-year-old man who had an open cholecystectomy 15 years ago presents with 36 hours of colicky central abdominal pain, repeated vomiting, and increasing abdominal distension. He has not passed flatus or faeces for 24 hours. On examination: dehydrated, BP 100/70, pulse 110, abdomen distended with tinkling bowel sounds and no peritonism.

Questions

a) What is the most likely diagnosis and cause? (2 marks)

Diagnosis: Acute small bowel obstruction (SBO). Cause: Adhesions from previous open cholecystectomy (adhesions are the commonest cause of SBO, 60%). The absence of peritonism means no strangulation at present.

b) Describe four initial resuscitation measures. (4 marks)

1. NBM (nil by mouth).
2. NG tube (nasogastric) — decompress stomach, relieve vomiting, monitor output.
3. IV fluids — aggressive crystalloid resuscitation (Hartmann's or normal saline) to correct dehydration. Replace deficit + ongoing losses.
4. Urinary catheter — monitor urine output (target >0.5 mL/kg/hr). Also correct electrolytes (especially K+).

c) What investigation would confirm the diagnosis and identify the cause? (2 marks)

CT abdomen/pelvis with IV contrast — gold standard. Identifies the transition point (site of obstruction), cause (adhesions, hernia, tumour), and signs of strangulation (bowel wall thickening, mesenteric oedema, free fluid, pneumatosis intestinalis).

d) How would your management change if the patient developed constant severe pain, fever 38.5C, and a rigid abdomen? (2 marks)

These signs indicate STRANGULATION (bowel ischaemia). Management changes to EMERGENCY LAPAROTOMY — no further conservative trial. At laparotomy: adhesiolysis, assess bowel viability, resect non-viable segments, primary anastomosis or stoma.