
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
Ogilvie syndrome, also known as acute colonic pseudo-obstruction (ACPO), is a rare dilatation of the colon without evidence of mechanical obstruction.[1] The condition is named after William Heneage Ogilvie, who published the first report of colonic pseudo-obstruction in 1948.[2] ACPO can lead to massive dilatation of colonic segments—particularly the cecum, which is at increased risk of perforation and may be fatal.[1,3]
ACPO tends to occur in patients who are hospitalized and debilitated or who have recently undergone surgery,[3,4] particularly orthopedic, cardiothoracic, or spinal procedures.[5] Patients typically present with symptoms of bowel obstruction, such as abdominal distention, nausea, vomiting, constipation, and/or abdominal pain.[6]
The image above shows multiple skip lesions in the small intestine of a geriatric patient with nonocclusive mesenteric ischemia associated with Ogilvie syndrome.
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
The abdominal computed tomography (CT) scan shown is from an elderly patient with ACPO. The marked gaseous distention of the colonic loops with air-fluid levels is an expected finding on abdominal imaging.
What is the general prevalence of ACPO in the United States?
- 1 in 10
- 1 in 100
- 1 in 1,000
- 1 in 10,000
- 1 in 100,000
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
Answer: C. 1 in 1,000
There are an estimated 100 cases of ACPO per 100,000 hospital admissions.[7] A large-scale database study of the National Inpatient Sample found that the prevalence of ACPO was 0.098% in US patients discharged from 1998 to 2011 (see table above).[3] Rates of medical complications are about 45.7%, and those of procedural complications are around 15.9%; mortality is a reported 7.7%.[3]
The cecum and right ascending colon are most often involved in ACPO.[7] The top image shows the average diameter of the cecum, ascending colon, transverse colon, descending colon, rectosigmoid region, and rectum. The cecum is at high risk of perforation due to its large diameter (8.7 cm).
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
What underlying mechanism is best associated with ACPO?
- Failure of migration of neural crest cells
- Accumulation of ingested material in the colon
- Idiopathic
- Germline mutation
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
Answer: C. Idiopathic
The mechanism underlying ACPO remains poorly understood. However, the etiologies of other causes of colonic and gastrointestinal (GI) obstruction are well-defined in the literature.
The image above is a radiographic example of Hirschsprung disease, a congenital enlargement of the colon due to failure of the migration of neural crest cells.[8] Accumulation of ingested materials, known as bezoars, can cause GI obstruction from being indigestible.[9] Germline mutations in familial adenomatous polyposis are associated with an increased risk of colorectal carcinoma, which may present with obstructive symptoms.[10]
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
An 81-year-old male patient with a past medical history of Alzheimer dementia and chronic constipation is admitted for lack of bowel movements for the past 5 days. The patient lives at home with his daughter and her family. He uses a walker to ambulate. He denies fever, chills, recent weight loss, and bleeding from the rectum, but he admits to nausea and vomiting.
On physical examination, the patient's abdomen appears distended, and there is diffuse, low-intensity abdominal pain on palpation. Bowel sounds are diminished on auscultation. A CT scan of the abdomen showed diffuse colonic dilatation, including of the cecum. There is no evidence of mechanical obstruction. What is the most likely diagnosis?
- Ogilvie syndrome
- Hirschsprung disease
- Gastric bezoar
- Ulcerative colitis
- Inflammatory bowel disease
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
Answer: A. Ogilvie syndrome
This patient has ACPO. The abdominal radiograph shows the characteristic dilatation of the colon associated with this condition without evidence of a mechanical obstruction. Notably, the patient has nonspecific symptoms of ACPO such as abdominal pain and distention, nausea and vomiting, and a history of chronic constipation. The patient's electronic medical record was reviewed for all potentially contributory medical conditions; reconciliation of his medications was completed; and intravenous (IV) fluids were administered.[11]
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
This CT scan shows distention of the rectum without obvious signs of mechanical obstruction. These findings are consistent with pseudo-obstruction.
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
As noted, ACPO constitutes a dilatation of the colonic segments due to nonmechanical obstruction. In this setting, the cecum is particularly vulnerable to adverse events due to increased wall tension. The law of Laplace is used to describe the relationship between the pressure necessary to stretch the walls of a hollowed viscus, the tension in the wall of the viscus, and the radius.[12]
Which of the equations below best represents the law of Laplace?
- P = 2T / r
- P = 2T / r2
- P = T / 2r
- P * T = 2r
- P * T = r2
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
Answer: C. P = T / 2r
According to the law of Laplace, the pressure is equal to the tension divided by the diameter.[13]
In ACPO, dilatation of the cecum puts added pressure on the wall of the colon, increasing the risk of ischemia and perforation.[14] Classically, dilatation of the cecum larger than 10 cm is considered the threshold for heightened risk of adverse events such as colonic ischemia and perforation.[15] Distention of the cecum for longer than 6 days is also considered a risk factor.[16] If, after 7 days, no endoscopic decompression or surgical intervention is undertaken, mortality appears to increase five-fold.[7]
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
The patient shown has experienced abdominal distention for the last 24 hours. Imaging reveals the cecum is approximately 8 cm dilated.
What conservative pharmacotherapy is the best choice for colonic decompression in this patient?
- Methylnaltrexone
- Erythromycin
- Metoclopramide
- Prucalopride
- Neostigmine
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
Answer: E. Neostigmine
The patient can be administered 2.5 mg of IV neostigmine over a period of 3 minutes.[11] Neostigmine has been shown to be the most effective pharmacotherapy for acute decompression of the colon.[17] Other medications have demonstrated less efficacy as candidates for decompression.
Peripheral opioid receptor antagonists such as methylnaltrexone have been suggested as alternatives, but further research is warranted.[18] Erythromycin, a bowel motility agent, has shown limited effectiveness in ACPO, such as in the pediatric population[19]; similarly, metoclopramide, another prokinetic agent, has been suggested.[15] Prucalopride, a second-generation selective, high-affinity serotonin receptor partial agonist, has been used to treat refractory ACPO.[20]
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
In the case under discussion, the first dose of neostigmine was ineffective in decompressing the colon, after which additional doses were administered, also without improvement. Endoscopic decompression was then attempted and unsuccessful.
The patient appears pale and complains of severe abdominal pain, worse in the right lower quadrant. His abdomen appears more distended than it was yesterday, his temperature is 100.4°F (38°C), and he is tachycardic. A complete blood cell count shows leukocytosis.
Which of the following is the correct indication for surgical intervention?
- Failure of conservative treatment
- Ischemia
- Perforation
- Peritonitis
- All of the above
Ogilvie Syndrome (Acute Colonic Pseudo-obstruction): Early Recognition and Treatment Are Key
Answer: E. All of the above
Indications for surgical intervention include failure of conservative therapy, signs of ischemia, perforation, and peritonitis.[15] However, early studies have indicated mortality to be as high as 44% with surgery[6]; therefore, patients should be managed expeditiously and aggressively with conservative treatments and nonoperative management prior to proceeding to the operating room.[15]
Colonoscopic decompression has been shown to be successful in as many as 85% of patients with ACPO and can be repeated as many times as is necessary.[11] However, colonoscopy is contraindicated in the setting of perforation or peritonitis.[21] Note also that emergency cases, female sex, and comorbid metastatic cancer and chronic obstructive pulmonary disease have been identified as risk factors for unsuccessful colonoscopic decompression.
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