Bowel obstruction

Drip and suck, but know when to operate

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Causes

Small bowel: adhesions (most), hernias, tumours, Crohn’s, gallstone ileus, intussusception
Large bowel: colorectal cancer (most), volvulus, diverticular stricture
Pseudo-obstruction (Ogilvie’s) and ileus are functional

Colicky pain, vomiting (early in proximal SBO), distension, absolute constipation (early in LBO)
Tinkling bowel sounds; look for scars and hernias, do a rectal exam
Strangulation: constant pain, fever, tachycardia, peritonism, raised lactate

X-ray rule 3-6-9: small bowel over 3 cm, colon over 6 cm, caecum over 9 cm
Valvulae conniventes cross the whole small bowel; haustra do not cross the colon
CT with IV contrast: level, cause and signs of ischaemia or a closed loop
Sigmoid volvulus: “coffee bean” from the pelvis

IV fluids, NG tube, catheter and fluid balance, analgesia
Correct potassium and magnesium
Adhesional SBO without strangulation: conservative with a water-soluble contrast study (contrast in the colon within 24 h predicts resolution)
Operate for strangulation, closed loop, hernia, or failure to settle (about 48–72 h)
Sigmoid volvulus: flexible sigmoidoscopic decompression, then consider elective resection
Malignant LBO: resection (Hartmann’s or anastomosis) or a stent as a bridge

Closed-loop obstruction with a competent ileocaecal valve: caecal perforation risk (caecum over 12 cm)
Femoral hernia in an elderly woman
Ogilvie’s: exclude a mechanical cause with CT, stop opioids, correct electrolytes; neostigmine or colonoscopic decompression