Acute colonic pseudo-obstruction

Acute colonic pseudo-obstruction (or “Ogilvie’s syndrome”) is an under-recognized disorder characterized by acute and extensive dilatation of the colon in the absence of an anatomic lesion obstructing the gastrointestinal tract.

The condition is uncommon, however it is vital to recognize as, untreated, it is potentially lethal.

It can be caused by a range of conditions, however post partum, post Caesarean section women are at particular risk.

The cecum, with its larger diameter, requires less pressure to increase in size and in wall tension, and hence is the most frequent site for perforation. The greater the dilation, the more likely perforation will be, especially ≥ 10 cm. 3

Acute colonic pseudo-obstruction (ACPO) should be considered in all women with symptoms of ileus after Caesarean Section, who present with progressive abdominal distension 2 – 12 days after caesarean section

History

Ogilvie syndrome is named for the British surgeon Sir William Heneage Ogilvie (1887-1971), who first described the condition in 1948.

Epidemiology

The true incidence of Ogilvie’s syndrome is unknown as many mild cases resolve spontaneously.

There is no reliable national or international data for its frequency.

In obstetric cases, caesarean section with spinal anaesthesia seems to be the most common operative procedure associated with this syndrome.

It has, however, also been reported after caesarean hysterectomy and vaginal births.

There is no data on predisposing factors.

Classification

Pseudo-obstruction syndromes can be divided into:

1. Acute (or “Ogilvie’s syndrome”)
   • In acute colonic pseudo-obstruction the colon may become massively dilated and if it is not decompressed, the patient risks perforation, peritonitis, and death.
2. Chronic forms

Physiology

Colonic motor and secretory functions are mediated by the autonomic nervous system.

The sympathetic nervous system arises from the spinal cord at the level of the thoracic and lumbar spinal cord.

Parasympathetic innervation of the colon is delivered from two sources:

• From the ascending colon to the splenic flexure parasympathetic innervation is supplied by the vagus nerve.
• Distal to the splenic flexure, parasympathetic innervation is via lumbar nerves from spinal segments S2 to S4.

Sympathetic innervation of the colon is via:

• The celiac plexus
• The mesenteric ganglia

In general, the parasympathetic nervous system increases gut motility and the sympathetic system decreases motility.

Abnormalities of the autonomic nervous system, characterized by sympathetic dysfunction, parasympathetic dysfunction, or a combination of both, have been used to explain the etiology of Acute colonic pseudo-obstruction (ACPO).

In contrast to Sir William Heneage Ogilvie’s initial theory of “sympathetic deprivation,” the benefit of neostigmine suggests that parasympathetic failure is more likely to be the etiology for Ogilvie’s syndrome.

Pathophysiology

Physiological ileus is an expected physiological consequence of abdominal surgery and has been defined as:

• Disruption of normal intestinal peristalsis that usually persists for 0 – 24 hours in the small intestine, 24 – 48 hours in the stomach, and up to 72 hours in the distal large colon.

This type of ileus generally resolves without serious sequelae.

A pathologic ileus is suspected when return of intestinal function is:

• Delayed
• Or symptoms develop

The aetiology of a small bowel ileus can differ from a large bowel ileus due to local neurological, hormonal and anatomical factors.

Causes

Patients with Ogilvie’s syndrome have underlying medical or surgical conditions that predispose them to the syndrome.

Pseudo-obstruction appears to related to an autonomic dysfunction with:

• Decreased parasympathetic activity
• And/or sympathetic stimulation

Obstetric related

Caesarean sections are thought to more significantly effect distal large bowel motility due to:

1. Minimal intraoperative small bowel handling
2. Disruption of the sacral plexus through spinal anaesthesia
3. Compression by the gravid uterus
4. Opioid use

Distal large bowel ileus causes proximal accumulation of gas and fluid, with the caecum being most at risk of over-distension and perforation.

This variant of ileus is known as Acute Colonic Pseudo-Obstruction or Ogilvie’s Syndrome and if unrecognized it is associated with significant morbidity.

Additionally, pregnancy itself predisposes to Ogilvie’s syndrome due to:

1. Prolonged gastrointestinal transit time in the third trimester
2. Increased progesterone levels
3. Reduced physical activity
4. Dietary changes such as iron supplementation

Non-obstetric related

Other non-obstetric causes include:

1. Abdominal/pelvic surgery
2. Trauma
3. Serious sepsis
4. Medications (opioids, anticholinergics, spinal anaesthetics)
5. Electrolyte disturbances
6. Diabetes
7. Renal failure

Complications

Despite no mechanical obstruction, complications include bowel necrosis and perforation (especially if caecal dilatation ≥ 10 cm), peritonitis, septic shock, and death.

Significant fluid losses can also occur into the distended bowel.

Clinical Features

Should be considered in women post-Caesarean Section with progressive abdominal distension 2–12 days post-op.

Signs and symptoms include:

• Vomiting
• Abdominal distension (hyper-resonant)
• Reduced flatus
• Abdominal pain or tenderness
• Altered bowel sounds
• Signs of perforation: fever, tachycardia, hypotension, peritonism

Investigations

Blood tests

• FBE
• U&Es/glucose
• CRP
• LFTs

Imaging

Plain Radiography:

• First-line; shows colonic dilation often confined to caecum/right colon.

CT Abdomen/Pelvis:

• Best for confirming diagnosis, measuring caecal diameter, ruling out perforation, or other differentials

Radiological Differential Diagnoses

• Adynamic ileus
• Mechanical obstruction
• Toxic megacolon
• Ischaemic colitis
• Sigmoid/caecal volvulus

Management

1. Conservative (if caecal diameter ≤ 10 cm and no perforation)

• Nil by mouth
• Nasogastric tube
• IV fluids
• Analgesia (minimise opioids)

2. Medical (if caecal diameter ≥ 10 cm or conservative fails after 24h)

• Neostigmine 2 mg IV over 3–5 mins (monitor for bradycardia)
• Repeat if needed

3. Decompression

• Colonoscopy with/without decompression tube
• Excludes mechanical obstruction

4. Surgical

• Laparotomy with resection for perforation or peritonitis
• Cecostomy for refractory cases

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References

FOAMed

• Farkas J. Acute colonic pseudo-obstruction (Oglivie’s syndrome). Emcrit

Publications

• Ogilvie H. Large-intestine colic due to sympathetic deprivation; a new clinical syndrome. Br Med J. 1948 Oct 9;2(4579):671-3.
• Wells CI, O’Grady G, Bissett IP. Acute colonic pseudo-obstruction: A systematic review of aetiology and mechanisms. World J Gastroenterol. 2017 Aug 14;23(30):5634-5644.
• E. Ford, M. Bozin, T. Cade,  J. McCormick, S. Shedda, A. Skandarajah. Consider Acute Colonic Pseudo-obstruction (Ogilvie’s Syndrome): A review of radiological investigations for symptoms of ileus post Caesarean Section. ePosters on Line – RCOG World Congress 2018 Singapore, March 21-24, 2018
• Dennis Wei Jian Gonga, Victor Jian Yuan Chin. Ogilvie’s Syndrome With Cecal Perforation Post Cesarean Section: A Case Report Clin Gynecol Obstet. 2018; 7(1): 23 – 25.
• Daniel J Bell, Gagandeep Singh; Colonic pseudo-obstruction, in Radiopedia
• Kimberley J. Norton-Olda, Nicola Yuenb, Mark P. Umstad. An Obstetric Perspective on Functional Bowel Obstruction After Cesarean Section: A Case Series. J Clin Gynecol Obstet. 2016;5(1):53-57