Ogilvie syndrome overview

# Overview
Ogilvie syndrome is defined as the obstruction of the colon with no mechanical reason and thereby, it is called pseudo-obstruction (not a true obstruction). The colonic pseduo-obstruction pathogenesis is thought to be due to impairement of the autonomic nervous system. The impairment includes the parasympathetic fibers of S2-S4 ending up with atonic colon and obstruction. However, in some cases the autonomic plexus in the colon is intact. The pseudo-obstruction is commonly caused by trauma, major surgeries, and myocardial infarction. Ogilvie syndrome must be differentiated from other causes of abdominal distention as volvulus and diverticulitis.The incidence of Ogilvie's syndrome is 100 per 100,000 individuals. Ogilvie's syndrome commonly affects patients more than 60 years and it is more prevelant int he men more than women. Common risk factors of Ogilvie's syndrome include having neurologic disorders, taking narcotic medications, and trauma. If left untreated, of patients with acute colonic pseudo-obstruction may progress to develop intestinal perforation which is life threatening complication. Common complications of Ogilvie's syndrome include colonic ischemia and intestinal perforation. Prognosis of Ogilvie syndrome depends on the underlying cause of pseudo-obstruction. Common symptoms of Ogilvie's syndrome include abdominal pain, abdominal distention, nausea, vomiting, and weight loss.The laboratory findings of colonic pseudo-obstruction may include leukocytosis due to the underlying disease not due to the pseudo-obstruction itself. Many patients with Ogilvie syndrome may have metabolic imbalance which include hypokalemia and hypocalcemia. On abdominal x-ray, Ogilvie syndrome is associtated with dilated bowel with air-filled colon and normal haustral markings. Abdominal CT scan is performed in suspected cases of colonic pseudo-obstruction to detect the site of the obstruction. Management of Ogilvie syndrome depends mainly on the supportive care measures which include include treatment of the underlying cause of the obstruction, terminating the concurrent medications that may cause intestinal dysmotility, and administration of intravenous fluids and saline. Neostigmine can be used for the medical treatment in unresponsive cases to the supportive care. Surgery is usually reserved for patients with either colonic ischemia, intestinal perforation, or sepsis. Surgical techniques include total colectomy, ileostomy, or Hartmann's procedure.

# Historical Perspective
Acute intestinal pseudo-obstruction was first reported by Dr. William Heneage Ogilvie in 1948 and the syndrome was named on him after that.

# Classification
Ogilvie's syndrome can be classified based on the duration of the disease into acute or chronic.

# Pathophysiology
The colonic pseudo-obstruction pathogenesis is believed to be due to impairment of the autonomic nervous system. The autonomic impairment may involve the parasympathetic fibers of S2-S4 which is responsible for innervation of the distal colon and may lead to atonic colon and proximal obstruction. In few cases, Ogilvie's syndrome (colonic pseudo-obstruction) may show atrophic myopathy with thinned colonic wall and intact myenteric plexus.

# Causes
Common causes of Ogilvie's syndrome include trauma, gynecological surgeries, major surgeries as hip replacement, and myocardial infarction. Other causes include causes of non mechanical bowel obstruction as acid base imbalance, acute pancreatitis, apoplexy, and cancers.

# Differentiating Hereditary pancreatitis from Other Diseases
Ogilvie syndrome (colonic pseudo-obstruction) must be differentiated from other diseases that cause abdominal distention and abdominal pain such as irritable bowel syndrome, volvulus and acute diverticulitis.

# Epidemiology and Demographics
The incidence of Ogilvie's syndrome is 100 per 100,000 individuals. Ogilvie's syndrome commonly affects patients more than 60years and it is more prevelant int he men more than women.

# Risk Factors
Common risk factors of Ogilvie's syndrome include having neurologic disorders, taking narcotic medications, and trauma. Other risk factors include systemic lupus erythematosus, alcoholism, and multiple myeloma.

# Screening
There is insufficient evidence to recommend routine screening for Ogilvie's syndrome.

# Natural History, Complications, and Prognosis
If left untreated, of patients with acute colonic pseudo-obstruction may progress to develop intestinal perforation which is life threatening complication. Common complications of Ogilvie's syndrome include colonic ischemia and intestinal perforation. Prognosis of Ogilvie syndrome depends on the underlying cause of pseudo-obstruction.

# Diagnosis

## History and Symptoms
Common symptoms of Ogilvie's syndrome include abdominal pain, abdominal distention, nausea, vomiting, and weight loss.

## Physical Examination

## Laboratory Findings
There are no specific diagnostic laboratory findings associated with Ogilvie's syndrome. The laboratory findings may include leukocytosis due to the underlying disease not due to the pseudo-obstruction itself. Many patients with Ogilvie syndrome may have metabolic imbalance which include hypokalemia and hypocalcemia.  Other laboratory tests that can be performed to exclude other causes include complete blood count, lactate levels, and thyroid hormone levels.

## X-ray
On abdominal x-ray, Ogilvie syndrome is associtated with dilated bowel with air-filled colon and normal haustral markings.

## Ultrasound
There are no ultrasound findings associated with acute colonic pseudoobstruction (Ogilvie's syndrome).

## CT scan
Abdominal CT scan is performed in suspected cases of colonic pseudo-obstruction to detect the site of the obstruction. Abdominal CT scan may show the presence of dilation of the large bowel without evidence of mechanical obstruction and the colonic dilation may extend to the rectum.

## MRI
There are no MRI findings associated with Ogilvie syndrome.

## Other Imaging Findings
There are no other imgaing findings associated with acute colonic pseudo-obstruction (Ogilvie's syndrome).

## Other Diagnostic Studies
There are no other diagnostic findings associated with acute colonic pseudo-obstruction (Ogilvie's syndrome).

# Treatment

## Medical Therapy
Supportive care is the first line of management of the colonic pseudo-obstruction. The supportive measures include treatment of the underlying cause of the obstruction, terminating the concurrent medications that may cause intestinal dysmotility, and administration of intravenous fluids and saline. Neostigmine can be used in the cases of pseudo-obstruction resistant to the supportive measures. Non-surgical techniques can be performed to decompress the obstruction and it includes colonoscopic decompression and percutaneous cecostomy.

## Surgery
Surgery is not the first-line treatment option for patients with Ogilvie syndrome. Surgery is usually reserved for patients with either colonic ischemia, intestinal perforation, or sepsis. Surgical techniques include total colectomy, ileostomy, or Hartmann procedure.

## Primary Prevention
Effective measures for the primary prevention of Ogilvie syndrome include supportive care measures as treatment of the underlying cause of the obstruction, terminating the concurrent medications that may cause intestinal dysmotility, and administration of intravenous fluids and saline.

## Secondary Prevention
The primary and secondary prevention strategies for Ogilvie syndrome are the same.