What is Intestinal Pseudo-Obstruction?
Intestinal pseudo-obstruction is a condition where the intestines expand without any physical blockage. This causes signs and symptoms similar to a real bowel obstruction – including nausea, vomiting, a bloated abdomen, and severe constipation. These signs are evident through x-ray or CT scans. The condition can be either acute (short-term) or chronic (ongoing).
Acute colonic pseudo-obstruction, also known as Ogilvie syndrome, usually impacts the larger part of the intestine. The actual cause is still unclear, but it seems to involve a disruption in the control of the nervous system over the intestines. This condition is mostly observed in patients who have recently had surgery or are seriously ill. The first steps in managing it involve resting the bowel, sucking out stomach contents through a tube inserted into the nose (nasogastric decompression), administering fluids through a vein, and treating any underlying cause.
If these initial treatments do not work, options may include administering a drug called Neostigmine, or carrying out a procedure to relieve the pressure in the intestine. This could be achieved through a scope inserted down through the throat (endoscopic), through the skin (percutaneous), or via surgery.
Chronic intestinal pseudo-obstruction is a less common form of the condition. It tends to cause feelings of fullness after eating only a small amount, nausea, bloating, and a distended abdomen. The causes are usually infections, metabolic disorders, nerve problems, autoimmune disorders, or of unknown origin.
What Causes Intestinal Pseudo-Obstruction?
Acute intestinal pseudo-obstruction, a condition where the intestines behave as though there is a blockage but there’s actually none, has no known exact cause. But, some theories indicate that factors like reduced activity of the body’s ‘rest and digest’ response (parasympathetic activity), irregular controlling of stretching in the intestines, and lower numbers of nerve cells within the intestinal muscles may be involved. More specifically, lesser parasympathetic activity originating from a network of nerves called the sacral plexus might contribute to intestinal muscles becoming less active (colonic atony). There are also several possible contributors, such as decreased blood flow to the abdominal organs (splanchnic perfusion), certain medications, opiates, a shortness of potassium in the blood (hypokalemia), and the presence of high levels of urea in the blood (uremia).
Chronic intestinal pseudo-obstruction (CIPO), a long-term condition of the same disorder, is better understood. Diverse causes have been identified, including nerve disorders (neuropathies), muscle disorders (myopathies), or irregularities in certain cells within the intestinal wall (interstitial cells of Cajal). Various diseases that impair the pathway from nerves to muscles, like Hirschsprung disease, Parkinson’s, scleroderma, diabetes, Ehlers-Danlos syndrome, Fabry disease, and Chagas disease are also linked to CIPO. Most of the time, cases of CIPO randomly occur, but in rare instances, it can be genetic. Furthermore, some cancers and tumors, like small cell lung cancer, carcinoid tumors, and thymomas, have been linked to CIPO due to their production of an antibody attacking nerve cells (anti-Hu) which can cause inflammation and infiltration of the intestinal nervous system.
Risk Factors and Frequency for Intestinal Pseudo-Obstruction
Acute intestinal pseudo-obstruction is a condition that tends to affect men and people over 60 more often. It is reported to occur in about 100 out of every 100,000 hospital admissions each year. This condition is commonly found in patients who are in the hospital after undergoing surgery or suffering from a severe illness. Several factors have been linked to intestinal pseudo-obstruction, such as medication use, imbalances in the body’s metabolism, physical trauma, having a surgical procedure, and heart disease. It’s crucial to understand that this condition isn’t limited to a specific age group – it can develop in both children and adults.
However, a high number of patients with this condition also suffer from degenerative nerve and muscle disorders. Approximately 20% of patients receiving home parenteral nutrition – a treatment providing nutrients intravenously – have acute intestinal pseudo-obstruction. Unfortunately, in the United States, there are few studies giving detailed information about the condition. But in Japan, it shows a prevalence rate of 0.8 and 1.0 and an incidence rate of 0.21 and 0.24 per 100,000 adults for men and women, respectively.
Signs and Symptoms of Intestinal Pseudo-Obstruction
Intestinal pseudo-obstruction, also known as Chronic Intestinal Pseudo-obstruction (CIPO), is a medical condition that presents symptoms resembling blockage in the intestines. About 80% of people with this condition experience bloated or swollen stomach, a symptom known as abdominal distension. Other observed symptoms may include nausea, vomiting, feeling full too quickly (early satiety), constipation, and generalized abdominal pain. These symptoms could appear as a sudden flare-up, linger over a long period, or occur on and off. Patients may also show symptoms of a related neuromuscular disease.
Acute Colonic Pseudo-obstruction (ACPO), on the other hand, often develops in patients who are already in the hospital dealing with a severe illness or following surgery. Signs of a swollen stomach can become evident abruptly or days after. If patients start to display fever, severe abdominal pain, or signs of peritonitis (an inflammation of the inner layer of the abdomen), it may imply that the abdominal distension has led to reduced blood supply to the intestines (bowel ischemia) or a tear in the wall of the intestine (perforation).
Testing for Intestinal Pseudo-Obstruction
When someone has a condition called intestinal pseudo-obstruction, their abdomen often swells or distends. There are many reasons why someone might have a swollen belly, so doctors use imaging to understand what is happening.
An X-ray of the abdomen can show abnormalities in the bowel. The tell-tale sign of this condition is a colon that has expanded from the beginning part of the colon all the way to the part where it turns left or even further. But X-ray findings might not be enough to diagnose this condition.
An abdominal CT scan is often more informative than an X-ray. It allows the doctor to see if the bowel or colon is dilated. They can also ensure that there are no other issues causing the problem, such as blockages, hernias, narrowing, or growths. In the early stages of the disease, doctors can use other imaging tests such as giving a contrast substance for the patient to ingest or to inject before the imaging to rule out these other issues.
Laboratory tests can’t directly diagnose intestinal pseudo-obstruction, but there are some tests that your doctor may order to rule out other causes of belly pain. They may ask for tests to check your liver function and pancreas, count the cells in your blood the blood lactate (an acid that can build up in your body), and check for ischemia (decreased blood flow) or damage to the intestines. They might also test for vitamin and hormone levels, as well as signs of celiac disease and some infections that can affect the nerves inside the intestines. Antibodies — proteins that your immune system uses to fight disease — can also give a hint about this condition.
If the colon and rectum are distended or enlarged, this may suggest another serious condition called toxic megacolon. Your doctor might order a test of your stool to check for this. They will also check for low levels of potassium, magnesium, and calcium, which can occur with intestinal pseudo-obstruction, and replace these if needed.
When symptoms persist over time, your doctor might order more tests to find the cause. These can include upper endoscopy and colonoscopy to inspect the digestive system and locate any problem areas or blockages. If nothing unusual is found, a test called scintigraphy might be used. This involves swallowing tiny particles and getting a series of images to watch them move through the digestive system. Abnormal findings on this test could then lead to a manometry study, where pressure measurements are taken throughout the digestive tract to identify underlying issues and distinguish between muscle and nerve problems.
Because nerve disorders can cause problems with digestion, testing that examines the function of your nervous system could be used. For patients with severe digestion problems where the cause is already known, a biopsy, or tissue sample, might help identify abnormalities in the nerves in the intestines.
Treatment Options for Intestinal Pseudo-Obstruction
When someone has ACPO, which is a dilation or enlargement of the colon, the treatment usually involves reducing the size of the colon to prevent a lack of blood flow and rupture. For patients who are stable, initial management might involve repeated x-rays of the stomach area in order to monitor the size of the colon. During this time, it’s also important to address and treat any underlying causes of the condition. These might include abnormalities in the body’s salt levels, infections, or side effects from certain medications.
A nasogastric tube can be inserted through the nose and down to the stomach to help reduce the volume in the stomach and to prevent fluids from entering the lungs. Likewise, a rectal tube may be placed to help reduce the pressure in the colon. If there are still no improvements after 48-72 hours, a medication called neostigmine may be administered.
Neostigmine is a medication that helps to increase the levels of a chemical called acetylcholine in the body. This chemical is responsible for causing muscle contractions in the bowel, helping to move contents along more effectively. Due to the possibility of a slow heart rate as a side effect, patients need to be closely monitored when this medication is administered. The dose may need to be reduced for patients with certain heart conditions.
If medication isn’t successful, or isn’t suitable for the patient, colonoscopic decompression could be considered. This involves using a special type of tube, called a colonoscope, to suck out the air from the enlarged bowel. There also the option to put a decompression tube in the colon to prevent it from enlarging again.
If all the above measures fail, or if the patient’s condition continues to get worse, surgery may be the last option. This could involve placing a tube in a part of the body called the cecum to help it decompress, or surgically removing the affected section of the bowel. Any patient who develops peritonitis (inflammation of the abdomen lining) or becomes unstable because of a lack of blood to the bowel or a rupture could be evaluated for potential surgical removal of the affected bowel.
In the case of chronic symptoms, medications like erythromycin and metoclopramide could help with digestion issues. However, these medications haven’t been proven to be effective for long-term treatment. Some new medications are currently being studied, which could help improve stomach emptying and provide relief of symptoms.
It’s also very important to carry out proper nutritional assessments for patients with CIPO. For patients who struggle to eat normally, strategies might include frequent small meals or high-calorie drinks. If these strategies aren’t successful, a feeding tube may be placed in the stomach or small intestine. In some severe cases, patients may need to receive their nutrition intravenously, or through a vein.
What else can Intestinal Pseudo-Obstruction be?
Mechanical obstructions in the bowels can cause the area before the obstruction to swell or dilate. These obstructions may be from trapped abdominal hernias, strictures, twists in the bowel known as volvulus, or masses. You can see a sort of “transition point” on medical images where the part of the bowel before the obstruction is enlarged, and the area after it is squeezed. If contrast fluid is given orally or through an enema, an abrupt ending at the obstruction point may be visible.
Toxic megacolon, another type of obstruction, can cause the abdomen to swell, observed both physically and through abdominal imaging. People with this condition often demonstrate systemic inflammatory response syndrome, or SIRS, symptoms that include fever, increased heart and breathing rates, and altered mental functions. More specific symptoms like abdominal pain and bloody diarrhea are common, too. Toxic megacolon usually occurs with conditions like ulcerative colitis but also other types of colitis, such as ischemic, infectious, or pseudomembranous. Surgical evaluation for a colectomy with end ileostomy might be required if the patient’s condition worsens.
Lastly, fecal impaction, or a hardened stool that is stuck in the rectum or lower colon, could cause these areas to dilate or stretch. It’s crucial for doctors to perform a physical exam using a finger to check for stool that may be stuck. In addition, the stool can be detected through radiographs or CT scans. Once the blockage is relieved, patient’s symptoms usually go away.
What to expect with Intestinal Pseudo-Obstruction
The death rate for adults with Chronic Intestinal Pseudo-obstruction (CIPO) is around 10%. About one-third of these patients will need to receive nutrition through an IV (intravenous injection), a process known as parenteral nutrition. But this method can come with its own complications, estimated to occur in 45% to 80% of cases.
In children, the death rates for CIPO vary from 10% to 40%, and the dependence on parenteral nutrition can be as high as 60% to 80%.
For Acute Colonic Pseudo-Obstruction (ACPO), the course of the illness depends on if there is a development of a lack of blood supply to the bowel (ischemia) or a hole in the bowel (perforation). These conditions happen in 3% to 15% of cases. The mortality rate with ischemic bowel or perforation is 40%, compared to 15% if there is no perforation.
Possible Complications When Diagnosed with Intestinal Pseudo-Obstruction
Not treating colonic distension, a condition associated with intestinal pseudo-obstruction, can lead to dangerous complications. These complications include bowel ischemia or perforation, conditions where blood flow to the bowel is cut off or a hole breaks through the bowel wall. These conditions require immediate surgery for treatment. Additionally, if it is not confirmed whether the patient’s condition is due to a mechanical obstruction, giving the patient neostigmine can cause disastrous results, like a hole in the bowel.
Key Points to understand about colonic distension treatment:
- If not treated, colonic distension due to intestinal pseudo-obstruction can lead to serious complications.
- These complications, such as bowel ischemia or perforation, often need immediate surgery.
- Neostigmine should only be administered once a mechanical obstruction has been ruled out to avoid the risk of causing a perforation in the bowel.
Preventing Intestinal Pseudo-Obstruction
Intestinal pseudo-obstruction, a condition that isn’t very common and has a range of unclear symptoms, can cause patients to experience unexplained stomach swelling and feelings of sickness. If you have persistent symptoms like these, it’s a good idea to discuss them with a gastroenterologist, a doctor specializing in digestive system disorders.
Changes in your lifestyle, a review of your diet, or visualization of your digestive tract using a special tool (endoscope) may all be part of the process to identify more common causes of these symptoms. If these causes are ruled out, then the possibility that you might have intestinal pseudo-obstruction can be explored further.
If you have sudden, severe stomach swelling and have a hard time eating or drinking, you should seek immediate medical attention at the emergency room. Certain urgent problems, like appendicitis (inflammation of appendix), bowel obstruction (blockage in the intestines), or incarcerated hernias (abdominal tissue gets stuck) need to be checked for and ruled out before starting treatment for intestinal pseudo-obstruction.
