*read Schein's "common sense emergency abdominal surgery" for more info* **Small bowel** - adhesions - congenital malformations - hernias - [[Inflammatory Bowel Disease|Crohn's disease]] - [[Intussusception]] - tumours - superior mesenteric artery syndrome **Large bowel** - tumours (mostly sigmoid or rectum) - [[Sigmoid volvulus]] - faecal impaction - diverticulitis # imaging ## abdominal XR > - transverse lines (valvulae conniventes) go all the way across the diameter of the small bowel > - transverse lines (haustra) only go partly across the large bowel > - in general, loops of small bowel are central while large bowel is in the periphery ![[Pasted image 20240813155013.png]] a) small bowel obstruction. note valvulae conniventes crossing whole width of small bowel b) distal colon obstruction. note haustra crossing portion of bowel - abdominal XR is 75% sensitive, 50% specific SBO - gaseous distension of small bowel + no gas in the colon = complete SBO - gas distension of small bowel + minimal quantity of colonic gas = partial SBO - significant gas distension of both small bowel and colon = paralytic ileus - significant gas distension of colon + minimal distension of small bowel = colonic obstruction or pseudo-obstruction ## ultrasound in SBO - presence of dilated small bowel loops >25mm jejunum, >15mm ileum (generally just say >3.5cm) -- most sensitive and specific finding - prominent peristalsis distinguishes obstruction from ileus (unless late in obstruction when peristalsis may be absent) - pattern to-and-fro motion of bowel contents highly specific for SBO - *tanga sign* - presence of free fluid between bowel loops ![[Pasted image 20240813160205.png| dilated loop 3.5cm]] ![[Pasted image 20240813160319.png]] ![[Pasted image 20240813160530.png| tanga sign showing free fluid between loops of bowel; confers a poorer prognosis from high grade obstruction]] ## CT SBO - most sensitive and specific - determines cause of obstruction and transition point # management - IVF (often 2-3 fluid deficit) - decompression NGT - essential if perforation or ischaemia present - strongly indicated if vomiting - often only therapy required in SBO secondary to adhesions, as obstruction usually resolves once bowel is decompressed - usually of little benefit in partial obstruction or when symptoms are already resolving - sigmoidoscopy and rectal tube passage for [[Sigmoid volvulus]]