Acute Colonic Pseudo-Obstruction - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Acute colonic pseudo-obstruction, also known as Ogilvie syndrome or colonic pseudo-obstruction, was first discovered in 1948 by British surgeon Sir William Ogilvie. It is a rare acquired disorder characterized by abnormalities affecting the rhythmic muscular contractions and involuntary actions within the colon. The disorder causes the colon to act as if it is physically blocked (pseudo-obstruction), but in reality, there is no physical blockage. The problem lies in the colon's motor system, which stops moving food along, causing buildup inside the colon. Peristalsis movement passes food through the gastrointestinal tract in digestive organs with the coordination of muscles, nerves, and hormones.

The symptoms of acute colonic pseudo-obstruction are similar to other intestinal pseudo-obstructions, including nausea, vomiting, swelling of the abdominal region, abdominal bloating, and constipation. Additionally, some patients may experience loss of appetite, diarrhea, or gas buildup. The symptoms are similar to mechanical obstruction of the large intestine, but there is no physical obstruction; that is why it is known as pseudo-obstruction.

Mechanical obstructions include conditions such as tumors or scar tissues that can block the colon's passage. Ogilvie syndrome (acute colonic pseudo-obstruction) is always associated with an underlying disorder, trauma, or surgery (leading to scar tissue). The condition most commonly affects older adults with multiple health conditions or those who have undergone surgery or trauma. The treatment for acute colonic pseudo-obstruction can be conservative, but if left unrecognized or untreated, it can lead to serious life-threatening complications, including ischemia or perforation of the colon.

What Are the Causes of Acute Colonic Pseudo-Obstruction?

The exact cause behind Ogilvie syndrome or acute colonic pseudo-obstruction is not fully understood and remains controversial; however, the disorder often affects an individual with a current serious medical condition or who has undergone surgery. Some conditions and infections are recognized as the underlying causes of acute colonic pseudo-obstruction.

Three common conditions are associated with acute colonic pseudo-obstruction: infections, operative trauma, and heart diseases. Cardiovascular conditions like congestive heart failure or myocardial infarction (heart attack) can trigger the condition. Pneumonia and sepsis are also associated with acute colonic pseudo-obstruction or Ogilvie syndrome.

Surgeries associated with Ogilvie syndrome include abdominal surgery, orthopedic surgeries (particularly total hip replacement), neurological surgeries (including the brain and nervous system), and urologic and cardiac surgery. Additionally, cesarean deliveries (C-sections) have been known to trigger the syndrome.

Other diseases, such as pulmonary diseases, kidney diseases, respiratory failure, malignancy, metabolic disorders, and severe electrolyte imbalances, are also linked to the condition. Consumption of certain medications, such as anticholinergics, Amphetamines, steroids, opioids, antipsychotic medications, immunosuppressants, and spinal anesthesia, can also lead to acute colonic pseudo-obstruction.

The dysfunction is believed to stem from issues inside the autonomic nervous system, which is responsible for the colon's involuntary motor functions. This leads to disrupted peristalsis.

What Are the Symptoms Observed in Acute Colonic Pseudo-Obstruction?

Ogilvie syndrome symptoms vary from one patient to another. It can be severe and even life-threatening and tends to present itself in a hospitalized patient, most commonly after surgery.

Common symptoms of acute colonic pseudo-obstruction or Ogilvie syndrome are:

• Abdominal pain, bloating, nausea, vomiting, and swelling in the abdomen.
• Loss of appetite, bloating, gas, constipation, or diarrhea also may be observed.

Abdominal distension may take days to develop, but it can also arise rapidly within 24 hours following the development of the disease. Other symptoms include fever, an elevated white blood cell (WBC) count, and abdominal tenderness. The colon has been reported to dilate over 4.72 inches in some patients, which can heighten the risk of more serious complications such as ischemia and perforation.

In severe conditions, ischemia and perforation within the colon lead to spilling within the abdominal cavity. This results in fever, pain in the abdominal region, sepsis, and severe blood infection. The part that is most susceptible to perforation is the cecum of the large intestine.

Ischemia of the colon causes damage to the tissues and death of the large intestine area involved. In most cases where ischemia and perforation occur, peritonitis is inflammation of the peritoneum, which is the tissue that lines the inside of the abdominal wall.

Which Population Is Affected by Acute Colonic Pseudo-Obstruction?

Ogilvie syndrome or acute colonic pseudo-obstruction can affect both males and females, but the most affected population is males. It is more common in individuals aged 60 and above, particularly those with underlying health conditions and hospitalized for acute illnesses or surgeries.

How to Diagnose Acute Colonic Pseudo-Obstruction?

The diagnosis of acute colonic pseudo-obstruction or Ogilvie syndrome depends on the patient’s detailed history, observed symptoms, and various specialized tests. Healthcare providers often use radiology techniques with contrast agents to diagnose the condition, such as contrast-enhanced computed tomography (CT) scans, which may also have a therapeutic effect as a laxative.

An X-ray of the colon is done to rule out the presence of any mechanical obstruction. If the radiograph reveals an expanded or dilated colon or abnormal air-fluid levels in the small bowel, it indicates intestinal obstruction.

Computed tomography or a water-soluble enema should be performed to help rule out a mechanical obstruction in cases where gas and distension are not present throughout the colon. In cases of a water-soluble enema, dye is inserted into the large intestine through a soft and thin tube through the rectum, and X-rays are taken.

What Can Be the Treatment for Acute Colonic Pseudo-Obstruction?

Treatment of Ogilvie syndrome includes drugs, decompression, support therapy, and surgery. The type of treatment will be determined by the dilatation of the colon and the possible complications developed, including ischemia or perforation. Treatment relies on the disease's progression besides the present symptoms, bowel condition, and the patient's age.

Thus, in perforation and ischemia, surgery should be done immediately. In other conditions like acute colonic pseudo-obstruction due to cardiac diseases, etiological treatment first may be considered as an initial approach.

Supportive therapy for acute colonic pseudo-obstruction includes withholding oral food and fluid intake and administering intravenous fluids to maintain the balance of electrolytes and fluid in the body. Nasogastric suction is also conducted to restrict air ingestion and prevent further colon dilation. A long, thin tube is placed within the rectum, which makes it easy to pass air and stool.

Thus, research studies have proved that administering the drug Neostigmine to an acute colonic pseudo-obstruction patient will decompress the colon quickly. This is because Neostigmine acts as a catalyst for prolonging the activity time of acetylcholine, which plays a vital part in transmitting signals from the nerves to muscles.

Other simple exercises that the patients may also prove useful are ambulation or positional maneuvers, which help unknot stool. If there is no response within the first 72 hours of conservative treatment, then the interventions become more aggressive and include colonic decompression (which helps lower pressure in the colon, thus alleviating the tension) or surgery.

Conclusion

Acute colonic pseudo-obstruction, also known as Ogilvie's syndrome, is a functional obstruction of the large intestine without mechanical obstruction. Therefore, it stops the flow of food and waste in the forward direction of the colon. In addition to these, more severe manifestations include nausea, vomiting, abdominal distension, and chronic constipation. In worse cases, they may lead to ischemia, perforation, and infection that, untreated promptly, may prove fatal. Early detection followed by early intervention is important in preventing these potential complications.