Ogilvie Syndrome or Acute Colonic Pseudo Obstruction

Ogilvie Syndrome

Also known as Acute Colonic Pseudo Obstruction, Ogilvie syndrome is a potentially fatal clinico-radiological conditon with features akin to large bowel obstruction without any mechanical obstruction. 

It is most commonly seen in elderly and usually unwell patients, with multiple probable or causative factors like electrolyte imbalances, diabetes mellitus, uremia (renal failure), recent surgery, medications (eg: Opioids) etc. Pathological analysis of resected specimens showed reduced intramural ganglion cells in most cases.

Even though there is no mechanical obstruction  this condition can lead to bowel gangrene and subsequent peritonitis, increasing the mortality risk. Therefore early identification of this entity and nasogastric suction, medical management (anticholinesterases), decompression by rectal tube, colonoscopic exsufflation is needed. Sometimes cecostomy under fluroscopic guidance and rarely cecectomy might be required.

Patients usually present with abdominal pain and distension with preserved bowel sounds on auscultation.

A plain abdominal radiograph usually shows dilated colonic loops (presence of haustra), more often the right colon and transverse colon, with relative lack of air fluid levels (which are more commonly seen with SBO). Rectal gas is usually seen in radiographs, indicating lack of mechanical obstruction.

CT is performed to rule out mechanical obstruction and to assess in detail the location, cause, length of obstruction, presence of vascular compromise, bowel wall thickening if any.

Ogilvie syndrome is characterized by dilated colonic loops, without any significant transition points in CT. An intermediate or gradual transition point may be seen close to the splenic flexure region. Bowel walls are not thickened. Small bowel loops are usually collapsed or non-dilated (In contrast adynamic ileus usually has dilated small bowel loops).

If the caecal diameter is <9cm, medical / conservative management  with anticholinesterases like neostigmine, nasogastric aspiration, rectal tube may suffice to relive the condition. CT enema can sometimes be therapeutic.

Caecal perforation risk is more with diameters >9cm, where a decompressive caecostomy may be required to prevent formation of gangrene and eventual perforation peritonitis.

Acute and chronic forms are recognized, with acute form being transient and associated with acute severe illness. Acute forms respond to neostigmine. Chronic forms rarely perforate, but are usually refractory, sometimes requiring subtotal colectomy for relief.

Differential considerations include Adynamic Ileus, Mechanical obstruction, pseudomembranous colitis, toxic megacolon, ischemic colitis and caecal / sigmoid volvulus.


Below is a case of Ogilvie syndrome in a 78yr old male with multiple co-morbidities and electrolyte imbalances, presenting with abdominal distension.

Here a gradual 'transition' point was seen in the proximal sigmoid colon.

The maximal caecal dimension in this case was 8.0cm (not shown).

 

The small bowel loops are seen collapsed. However in some cases of Ogilvie syndrome, due to incompetence of ileo-caecal valve, the distension can extend into the small bowel loops also.