Section: Colorectal Sub-section: Acute colorectal Curriculum: Curriculum, page 24
Definition
Non-mechanical distension of the colon due to transiently absent colonic motility.
Risk factors
- Elderly
- Frail
- Institutionalised
- Hospitalised for orthopaedic, gynaecological and abdominal operations
- Cardiac and infectious aetiologies.
Aetiology
- Thought to result from autonomic imbalance, particularly:
- ↓ Parasympathetic activity (esp. sacral outflow)
- ↑ Sympathetic inhibition
- Leads to suppression of colonic peristalsis → functional obstruction
- Triggers/Associated Conditions:
- Postoperative states (esp. pelvic/orthopaedic surgery)
- Trauma, severe infection, or sepsis
- Electrolyte disturbances – esp. hypokalemia, hypomagnesemia
- Medications – opioids, anticholinergics, calcium channel blockers
- Neurologic disease – Parkinson’s, MS, spinal cord injury
- Retroperitoneal pathology – may disrupt sacral nerves
Clinical
Abdominal distension, discomfort, nausea, vomiting and constipation
Investigations
- Xray shows significant dilatation of entire colon.
- Mechanical obstruction should be ruled out with CT with rectal contrast.
- Caecal diameter > 12 cm associated with higher rates of spontaneous perforation; mortality doubles when increases from 12 to 14 cm.
Management
Non-operative in absence of perforation or suspected ischaemia.
- Bowel rest, resuscitation, correction of electrolyte abnormalities
- Treat underlying cause. Check MSU.
- NG not necessary unless nausea/vomiting with small intestine and gastric distension.
- Medications inhibiting GI transit should be stopped: opiates, antidepressants, antipsychotics, calcium channel blockers, antidiarrhoeal agents, anticholinergics.
- Laxatives and enemas should also be avoided.
Medical
- Neostigmine can be considered
- Serious side-effects: bradycardia, bronchospasm, hypotension and asystole.
- Polyethylene glycol administered after initial resolution may increase sustained response after initial intervention.
Endoscopic
- Decompression can ease discomfort.
Surgical
- If all non-operative measures fail, surgical considered, however most high risk due to frailty and comorbidities. Default safe procedure is subtotal colectomy and end ileostomy.
- Decompressive ostomies do not prevent recurrence and increase morbidity and mortality.
- Poor surgical candidates can be considered for percutaneous tube caecostomy
- Issues: inadequate decompression, clogged tubing, retraction, dislodgement, skin erosion, abdominal wall infection, leakage, fistulisation, perforation and peritonitis.