What is Large Bowel Obstruction?
Large bowel obstruction, or blockage of the large intestine, typically emerges as an urgent situation. The causes may result in different symptoms before the condition becomes severe. Patients may be extremely sick, have an infection (or sepsis), be severely dehydrated, and have a weakened heart and circulation. This is especially true if they have a functioning ileocecal valve – a gate between the small and the large intestine. If this valve is working properly, it can stop the large intestine from relieving pressure by emptying into the small intestine, causing a closed-loop obstruction, a dangerous build-up of pressure.
What Causes Large Bowel Obstruction?
The most frequent reason for large bowel blockage, or obstruction, is colorectal cancer. In other words, about 40% of the time colorectal cancers are discovered because they cause emergencies such as these large bowel blockages.
There are also non-cancerous reasons for large bowel blockage. These can include narrow segments of the bowel due to diverticular disease or inflammatory bowel diseases, and twists in the bowel, particularly in the sigmoid colon which is near the end of the bowel. Sometimes, the sigmoid colon can even get trapped in a type of abdominal wall hernia on the left side, called a left inguinal hernia.
An outside pressure causing a blockage can occur, frequently in the pelvic region, and is often due to gynecological cancers.
Risk Factors and Frequency for Large Bowel Obstruction
Colorectal cancer, a type of cancer that affects the lower part of the digestive system, usually becomes more common around the age of 50. However, in most developed parts of the world, the rate of new cases has recently stabilized and even started to decrease a little. The overall chance of someone developing colorectal cancer at any point in their life is around 6%.
However, it’s important to be aware that this type of cancer is starting to appear more frequently in people under the age of 50. These younger patients don’t usually fit the criteria for regular screening tests, so it’s possible that their cancer may not be detected until it is advanced or aggressive, and they find themselves needing emergency care.
Signs and Symptoms of Large Bowel Obstruction
How a person experiences blockage in the large intestine depends on what caused the blockage and where it’s located. Here are different situations:
- When the blockage is due to colorectal cancer, it typically happens on the left side of the large intestine. This could be because cancer in this area is common, and stool is typically solid here because the part of the intestine here is smaller. Symptoms might include changes in bowel movements, such as switching between diarrhea and constipation. This happens because only liquid stool can get past the blockage. Sometimes, these changes can go unnoticed for weeks or even months before the person seeks medical help. Other symptoms may include rectal bleeding and a bloated or uncomfortable belly. The person might also be unable to pass stool or gas. Some of these patients might have a family history of colorectal cancer.
- If the blockage occurs due to a twist in the sigmoid colon (known as sigmoid volvulus), symptoms usually appear suddenly. This is often seen in people who are not very active and are prone to constipation, such as nursing home residents or bedridden patients. The symptoms primarily include a bloated abdomen rather than changes in bowel movements.
- The level of discomfort or pain varies. Because the large intestine doesn’t contract as much as the small intestine, patients may not feel as much pain as they would with a small intestine blockage.
- Suppose a person has a non-functional gate (known as ileocecal valve) between the small and large intestine. In that case, they might rid their large intestine of gas, which then collects in the small intestine, causing vomiting. However, in a person with a functional gate, continued bloating of the blocked part of the intestine can lead to severe pain in the lower right part of the belly and possibly a rupture in the cecum, a pouch at the beginning of the large intestine.
- When examining the abdomen, the doctor might notice significant bloating, hollow sounds when they tap on the belly, and the patient wincing from pain as pressure is applied and released in areas where a rupture may happen.
- If the person already has a rupture, their belly would be extremely tender and painful to touch.
- A rectal examination usually reveals an empty rectum, indicating no stool present.
Testing for Large Bowel Obstruction
If your doctor suspects a bowel issue, they might order standard blood tests to check your overall health and the health of your kidneys. These tests will help them understand how best to treat you and whether they can use certain types of scans, such as a CT scan with contrast, to get a better look at what’s going on.
An abdominal x-ray can give your doctor a view of your colon. This x-ray can show symptoms like a blocked, stretched-out colon, little to no gas in the rectum, or a specific “coffee bean” pattern, which usually indicates a twisted colon.
If there’s a concern that you might have a colon tumor, your doctor might order a CT scan of your chest, stomach, and pelvis. This scan helps to determine how advanced the disease might be and what the treatment options are.
If your doctor needs to use a colonoscopy to evaluate your bowel, it’s important to know that you shouldn’t take oral bowel preparation if you have a bowel blockage. Instead, your doctor might give you an enema and use a colonoscope with minimal air to reach the blockage and get the tissue samples they need for a diagnosis.
Treatment Options for Large Bowel Obstruction
Before any surgery, it’s crucial to ensure the patient is stabilized with intravenous fluids and any imbalances in their body salts are corrected. If the patient has a specific type of valve dysfunction in their digestive system, a nasal tube may be used to relieve the pressure in their stomach.
In cases of intestinal blockage due to cancer, surgery is usually the best course of action. The specifics of the procedure depend on how advanced the cancer is. If the cancer has spread to other parts of the body, creating an artificial hole, or stoma, in the abdomen often becomes the preferred choice, as it allows quicker access to chemotherapy treatments.
For patients whose cancer hasn’t spread, the goal is usually to remove the cancer, repair any damage, and provide further treatment as necessary. In these cases, a temporary stoma or a procedure to prop open the blocked section of the colon can be done as a first step before full cancer removal. This approach gives patients an opportunity to fully recover from the initial procedure and return to eating normally before going through more extensive surgery. However, these decompression steps should only be attempted if the patient’s bowels have not lost blood supply or perforated, and should not be tried in patients who have signs of inflammation or infection of the membrane lining the abdomen.
When the obstruction in the colon risks rupturing, or there are signs of reduced blood supply or bacterial infection in the abdomen, emergency surgery is necessary. This typically involves removing the section of the colon that’s at risk of rupturing as well as the blockage itself.
What else can Large Bowel Obstruction be?
- Megacolon (severe enlargement of the colon)
- Diverticulitis (inflammation of small pouches in your colon)
- Small bowel obstruction (blockage in the small intestines)
- Abdominal hernia (when an organ pushes through an opening in the muscle or tissue that holds it in place)
Possible Complications When Diagnosed with Large Bowel Obstruction
- Rupture of the appendix
- Damage or death of bowel tissue
- Severe infection spreading in the body
- Changes in body’s salt balance
- Losing too much water from the body
- Potential death
