INTESTINAL OBSTRUCTION

Interruption of the normal flow of intestinal content, due to mechanical obstruction (at small or large bowel level), or due to functional paralysis.

Causes

  • Small bowel mechanical obstruction: tumours, adhesions from previous surgeries or infections
  • Large bowel obstructions: tumours, volvolus, adhesions, inflammatory strictures (e.g. diverticulosis, etc.)

Clinical features

  • Small bowel obstruction: cramping abdominal pain, nausea, vomiting, abdominal distention. Due to the
    accumulation of fuids into the dilated intestinal loops, there is usually a varying degree of dehydration
  • Large bowel obstruction: bloating, abdominal pain, constipation, vomiting and nausea less frequent and
    mainly in proximal colon obstruction; signs of dehydration and shock come later.

Investigations

  • Abdominal X-ray (erect or left lateral decubitus, for airfluid level)

Differential diagnosis

  • Paralytic ileus (diffuse functional paralysis of small and large bowel due to drugs, biochemical abnormalities,
    abdominal infections etc)

MANAGEMENT

Pre-operative management

  • IV fluids (normal saline, Ringer’s Lactate)
    • To correct fluids deficit and replace ongoing losses plus maintenance fluids
    • Monitor haemodynamic status (pulse, blood pressure, skin turgor, level of consciousness,
      hydration of mucosae, urine output at least 0.5–1.0 ml/kg/hour)
    • It may take up to 6 hours to re-hydrate
    • If not responding to IV fluids, suspect septic shock
    • Insert urinary catheter to monitor urinary output
  • Nasogastric tube decompression
    • Pass NGT and connect with a drainage bag to empty the stomach in small bowel obstruction or
      when clinically indicated
    • Nil by mouth
  • Give appropriate antibiotics
    • Ceftriaxone 2 g IV once a day
    • Plus metronidazole 500 mg IV every 8 hours
  • If the patient is in severe colicky pain, administer pethidine 50-100 mg IV or IM
  • If surgery is indicated and the patient’s parameters are near normal after resuscitation,
    take the patient to the operating theatre for an appropriate surgical relief of the obstruction

Intra-operative fluid therapy

  • Blood loss, fluid aspirated from the gut and other fluid losses must be replaced
  • Maintenance fluid should be given: 5 ml/kg/hour Post-operative fluid therapy
  • Replace all fluid losses
  • Maintenance fluid
  • Use normal saline or Ringer’s lactate solution and 5% dextrose in the ratio 1:2 for the first 24-48
    hours post-operatively
  • Monitor for adequate rehydration

Post-operative antibiotics and analgesics

  • Continue with analgesics in the postoperative period. (Tramadol, pethidine, diclofenac,
    paracetamol; morphine may be used)
  • Continue with antibiotic treatment where clinically indicated (metronidazole +
    ceftriaxone +/- gentamycin)

In selective cases, non-operative treatment of intestinal obstruction (in particular small bowel
obstructions) can be tried

  • Indicated in appendicular mass, acute pyosalpingitis (PID), some patients with adheisions, pseudo obstruction, plastic peritonitis of TB, acute pancreatitis
  • Involves NGT decompression, intravenous fluid therapy and antibiotic therapy if indicated
  • Monitor clinical progression of obstruction using parameters of: abdominal pain, abdominal girth,
    amount and colour of NG aspirate, temperature, pulse
  • If no improvement after 72 hours or the NG content becomes fecolent, operate the patient