a) What are the radiological features of colonic pseudo-obstruction / Ogilvie's syndrome? (20% marks)
b) List six conditions which are associated with colonic pseudo obstruction (20% marks)
c) Briefly outline your approach to management. (60% marks)
Plain films: - Identical to mechanical obstruction: dilated bowel loops: may have fluid levels CT demonstrates dilated large bowel without a clear transition point or obstructing lesion.
Trauma, especially fractures
Recent surgery, especially involving spinal anaesthesia
Severe medical illness, such as pneumonia, myocardial infarction, or heart failure
Chemotherapy (e.g., all-trans retinoic acid, methotrexate, vincristine)
Retroperitoneal pathology, such as malignancy or haemorrhage
Medication (e.g., narcotics, phenothiazine’s, calcium channel blockers, alpha-2-adrenergic agonists, epidural analgesics)
Initial management of acute colonic pseudo-obstruction consists of conservative therapy in patients without significant abdominal pain or signs of peritonitis and those who have one or more potential factors that are reversible.
Treat underlying disease, stop aggravating drugs, avoid laxatives, and keep NPO. NG tube – encourage mobility. Consider opiate reversal agents e.g. GI naloxone or SC Naltrexone
If fail or progress consider neostigmine: In patients with caecal diameter >12 cm (varies) or failure of 24 to 48 hours of conservative therapy. Up to 2 mg slow IV and repeat if needed. Lower doses may also be effective. Studies have shown high response rate with low rate of recurrence. Side effects include abdominal pain, hypersalivation, vomiting and bradycardia. Perforation may occur if there is unrecognised mechanical obstruction.
Colonoscopy decompression: Those patients who fail or who have contraindications to neostigmine. Technically difficult and perforation is a risk. No randomised trials.
Surgery: In the absence of a colonic perforation, cecostomy tube or a segmental or subtotal resection with primary anastomosis can be performed. In the patients with a colonic perforation, a total colectomy, ileostomy, and Hartmann procedure are performed to retain the option of future ileorectal anastomosis
Management plan poorly structured in many cases. Overall reasonably well answered.
Radiological features of colonic pseudo-obstruction:
For ileus and constipation in general, you would expect the following risk factors:
Modifiable ICU-related risk factors
Non-modifiable disease risk factors
Most of this comes from Saunders et al (2005). Options for management of colonic pseudo-obstruction can be divided into categories:
Pharmacological (pro-motility) management
Interventional (decompressive) management
Ogilvie, Heneage. "Large-intestine colic due to sympathetic deprivation." British Medical Journal 2.4579 (1948): 671.
Choi, Ji Soo, et al. "Colonic pseudoobstruction: CT findings." American Journal of Roentgenology 190.6 (2008): 1521-1526.
Saunders, M. D., and M. B. Kimmey. "Systematic review: acute colonic pseudo‐obstruction." Alimentary pharmacology & therapeutics 22.10 (2005): 917-925.
Wells, Cameron I., Gregory O’Grady, and Ian P. Bissett. "Acute colonic pseudo-obstruction: A systematic review of aetiology and mechanisms." World journal of gastroenterology23.30 (2017): 5634.