What Is the Terminal Ileum?
The terminal ileum is part of the digestive system. The most distant portion of the small intestine, it aids in digestion by absorbing materials not previously digested by the jejunum, the middle portion of the small intestine. There are several medical conditions, such as Crohn's disease and certain types of cancer, that can have negative effects on it.
The first two portions of the small intestine are called the duodenum and the jejunum. This last portion of the intestine leads to a pouch known as the cecum, which connects the small intestine to the large intestine. A valve known as the ileocecal valve, or ICV, separates the terminal ileum from the cecum.
Materials that are not absorbed by the body by the time they leave the jejunum are precessed by the terminal ileum. This part of the small intestine is also responsible for the absorption of vitamin B-12. Bile salts produced by the liver are absorbed there as well.
There is actually nothing in the small intestine that would serve to separate the middle and last part of the small intestine. There are a few structural differences that allow a skilled professional to tell where one stops and the other begins, however. For instance, the jejunum is slightly darker in color, while there is a bit more fatty tissue located in the terminal ileum.
Crohn's disease is one of a number of medical conditions that produces problems in this area of the digestive system. This is an inflammatory bowel disease that currently has no cure. Treatment is aimed at reducing as many of the symptoms as possible, including nausea, weight loss, and diarrhea. Since Crohn's disease primarily affects this part of the intestine, vitamin B-12 absorption is often compromised and needs to be treated as well.
Lymphoma is a form of cancer affecting the lymphatic glands of the immune system. While this disease has many symptoms, those related to the terminal ileum include loss of appetite and significant weight loss. Chemotherapy or radiation treatments are sometimes necessary to combat aggressive forms of this disease. If tumors develop inside the small intestine, surgery to remove the tumor and repair any other damage may become necessary. Prognosis for this type of cancer is generally better than that involving other types, depending on the patient's overall health and response to treatment.
How Important Is the Terminal Ileum?
The terminal ileum may not be a common household topic, but its role is significant in our everyday lives. Many essential nutrients are absorbed in this area of our body, such as carbohydrates, B-12 vitamins, fatty acids, and amino acids- all necessary for sustenance and quality of life.
The ileum can also help keep the digestive process moving smoothly by releasing digestive hormones and controlling the flow of digested food. The cecum, or the valve dividing the small intestine from the large intestine, plays a significant role in the movement of waste through the body.
This area of the small intestine is prone to several diseases, including Crohn’s disease, parasitic disease, infectious disease, or even cancer. Due to the high-risk nature of this small intestine area, routine colonoscopy screenings often include a check of the terminal ileum and biopsies from the site if needed.
Crohn’s Disease and the Terminal Ileum
Crohn’s disease is a type of inflammatory bowel disease (IBD) that doctors can detect during a colonoscopy. It can affect any part of the gastrointestinal tract but is most commonly found in the ileum. Crohn’s Disease is a widespread chronic disease affecting an estimated 3 million Americans, causing inflammation or irritation of the intestine that may worsen with time.
The symptoms of Crohn’s disease can be hard to pin down, as most of the symptoms are common in other health problems, and people with Crohn’s are more likely to develop other chronic conditions. However, there are a few common symptoms associated with this disorder:
- Unexplained weight loss
- Nausea or vomiting
- Pain in abdomen
A diagnosis for Crohn’s disease typically involves an evaluation of medical and family history, a physical exam, blood testing, and a colonoscopy and/or diagnostic imaging. Once diagnosed, treatment usually consists of symptom relief and decreasing intestine inflammation. Crohn’s disease can also increase the risk of developing small bowel cancer.
Small Bowel Cancer and the Terminal Ileum
Cancers of the small intestine are rare, only accounting for about 2% of all gastrointestinal cancers. Even though they typically occur in the duodenum, there are a few types of cancer that can occur in the terminal ileum:
- Adenocarcinoma: The most common of small bowel cancers, it starts in the epithelial layer of the intestine.
- Lymphoma: This type of cancer starts in the intestine’s immune cells.
- Sarcoma: This cancer starts in the muscles and connective tissues of the intestine.
- Neuroendocrine tumors: The most common of the tumors found in the small intestine but are usually slow to progress.
Many symptoms of small bowel cancer can overlap with those of Crohn’s disease, so it can be challenging to differentiate between them without further testing. Some of the more unusual symptoms of small bowel cancer include dark black waste and the presence of a bowel obstruction.
Treatment depends largely on the type and location of cancer. Common treatments are chemotherapy, surgery, radiotherapy, or a combination of all three.
Is There Preventative Care for the Terminal Ileum?
Many diseases found in the terminal ileum are debilitating or chronic. It is essential to keep up with routine colonoscopies or appointments to prevent the disease from progressing and get the treatment required.
The CDC recommends having a colonoscopy at least every ten years once you reach 45 years old. You may have to undergo this procedure earlier or more often if you have an increased risk of cancer due to:
- Family history
- History of inflammatory bowel disease
- Genetic conditions such as Lynch Syndrome
Your physician may also recommend a colonoscopy earlier than recommended if you exhibit symptoms related to inflammatory bowel disease or cancer.
One of the best forms of preventative care is taking care of your body and living a healthy lifestyle. Studies suggest that obesity can make Crohn’s disease more severe and affect your body’s natural resilience to illness. A lack of physical activity or a low-fiber, high-fat diet can also increase your risk of developing small bowel cancer.
You can help to maintain your small intestine health by eating a diet high in fiber and low in both fat and processed foods, exercising regularly, and keeping your providers up to date on your symptoms and well-being.
@deany17 - I'm not a vegan myself, but I've discussed this with a friend of mine who is. (Many vegetarians eat eggs and/or dairy, and so could get B12 from that, whereas vegans don't consume any animal products.)
To be honest, I don't know how B12 reaches the parts of the body it needs from an injection. What I do know is that most vegans have no need of B12 injections. They get their B12 from nutritional yeast (yum), fortified breakfast cereals, fortified milk alternatives like soy milk, and vitamin tablets. There are plenty of ways to get B12 without eating animal products and without having shots.
I've heard that vegetarians often have inadequate intake of vitamin B12 because it is found in meat and animal protein foods, and that come get intramuscular injections of B12 are given to restore normal levels. But since it is an intramuscular injection, how is the B12 absorbed if it doesn't pass through the ileum? Does it just bypass the ileum and go to the liver for storage or does it enter the circulation, without the need for intrinsic factor, and reach the tissues that make blood cells?
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