The ileocecal valve, also known as the iliocecal valve or Bauhin valve, is the junction between the last portion of the small intestine, known as the ileum, and the first portion of the large intestine, known as the cecum. It serves as a sphincter, that is, it allows the passage of content from the ileum to the cecum but hinders its return. When this valve becomes incompetent, whether it is always open or always closed, it brings significant health problems.
This structure regulates the passage of liquid content from the small intestine to the large intestine, helping in the digestion process. This is why when the individual does not work properly, symptoms such as gas, lower abdominal pain, constipation or diarrhea can occur.
By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See «Book» section below) Bartleby.com: Gray's Anatomy, Plate 1075, Public Domain, https://commons.wikimedia.org/w/index. php? curid = 567026
The ileocecal valve plays an important role in the nutrition process as it is the only place in the digestive system where vitamin B12 is absorbed and where bile acids are absorbed.
Histology
The small intestine has a special type of mucosa that favors its function of absorbing nutrients. It consists of a layer of finger-shaped villi that has a great absorption capacity.
By Louisa Howard, Katherine Connollly - Dartmouth Electron Microscope Facility - http://remf.dartmouth.edu/images/humanMicrovilliTEM/source/1.html, Public Domain, https://commons.wikimedia.org/w/index.php ? curid = 771225
In the iliocecal valve there is a sudden change in the cellular pattern of the small intestine towards another type of mucosa. This is due to the function of the iliocecal valve and its contact with the large intestine.
The microscopic difference between the ileum and the iliocecal valve is clear, since while the mucosa has villi in the ileum, mucus-producing cells are observed in the valve.
In addition to this, in the small intestine there is a circular muscular layer that works to move the contents towards the colon. However, at the level of the iliocecal valve, this muscle layer is thicker and stronger because the valve acts as a sphincter.
Features
The main function of the iliocecal valve is to guarantee the passage of content from the small intestine to the large intestine and prevent its return. In addition to this, it is the only area of the small intestine where vitamin B12 is absorbed and where bile salts are processed for the digestion of fats.
The iliocecal valve is the structure that identifies the end of the small intestine and the beginning of the large intestine. For this reason, its hole is used as a reference when performing colon study procedures, such as colonoscopy.
In colonoscopy, a flexible camera is inserted through the anus to observe and evaluate the condition of the colonic mucosa. The study is completed by reaching the initial portion of the colon, known as the cecum.
The way in which the doctor recognizes that the camera is located in the cecum is through the identification of the ileocecal valve. When possible, the colonoscopy chamber is insinuated into the iliocecal sphincter to assess the status of the valve.
Related diseases
The iliocecal valve can lose its mobility and remain open all the time or closed all the time, causing different symptoms and diseases.
As the muscle of the terminal ileum increases, the iliocecal valve remains closed. This causes a partial obstruction of the small intestine that can be overcome if the intestinal content achieves enough pressure to open it.
When the ileocecal valve is open all the time, there may be a return of colonic contents into the small intestine.
What this means is that the digested content, which is now ready to begin its journey through the colon, is returned to the small intestine through the open valve.
This makes digested food stay longer in the small intestine, facilitating the growth of colon bacteria in the small intestine. This state is known as "intestinal bacterial overgrowth."
Structures neighboring the ileocecal valve can become diseased and alter its function. This is the case of tumors of the cecal appendix, terminal ileum and cecum.
What happens is that when the tumor begins to grow, it can cause obstruction of the orifice of the ileocecal valve and this causes an obstruction at that level. When there is an obstruction, the contents cannot pass from the small to the large intestine.
Diagnosis
Iliocecal valve dysfunction is diagnosed through the patient's medical history, radiological and endoscopic examinations.
The individual with iliocecal valve dysfunction may present with very nonspecific gastrointestinal symptoms. For this reason, the clinical diagnosis must be made by ruling out other diseases.
By means of radiology we can observe the disposition of gases in the abdomen and recognize if there is an obstruction in the small intestine.
When this portion of the intestine is not working properly, the patient may have abdominal pain, gas, diarrhea or constipation, and bad breath.
Once other diagnoses are ruled out and it is concluded that the problem may be in the iliocecal valve, different special tests are indicated.
Endoscopy and manometry
Endoscopy is a type of invasive evaluation that allows you to see the lining of the colon with a flexible instrument called an endoscope, which has a camera.
Through the camera, the physician can view the entire mucosa of the colon up to the iliocecal orifice and insert the instrument to assess the condition of the valve mucosa. Through this examination, the presence of tumors that are obstructing the lumen of the iliocecal orifice can be observed.
Another test that is used to evaluate the good function of the iliocecal valve is manometry. This study allows to measure the pressure at the level of the sphincter, with a special instrument called a manometer.
If the pressure is increased or decreased, a malfunction of the sphincter musculature is occurring.
Treatment
The therapeutic approach to iliocecal dysfunction will depend on what is causing the problem.
When sphincter pressure is abnormal, treatment is conservative. An attempt is made to improve the problem from special diets and vitamin supplements that help the patient with the poor absorption of nutrients that may exist.
If the problem is a mass or tumor that is growing and obstructs the lumen or obstructs the function of the iliocecal valve, surgical treatment is chosen with resection of the tumor.
If the evaluation shows that the tumor is infiltrating the iliocecal valve, it must also be resected to ensure adequate passage of the intestinal content to the colonic.
References
- Shou-jiang Tang and Ruonan Wu, "Ilececum: A Comprehensive Review," Canadian Journal of Gastroenterology and Hepatology. Taken from: hindawi.com
- Miller, L. S; Vegesna, A. K; Sampath, A. M; Prabhu, S., Kotapati; SK, & Makipour; K. (2012). Ileocecal valve dysfunction in small intestinal bacterial overgrowth: a pilot study. World journal of gastroenterology, 18 (46), 6801–6808.
- Bassotti, G; Bologna, S; Ottaviani, L; Russo, M; Dore, MP (2015). Intestinal manometry: who needs it ?. Gastroenterology and hepatology from bed to bench, 8 (4), 246–252.
- Holmes, R; Hourihane, D. O; Booth, CC (1961). The mucosa of the small intestine. Postgraduate medical journal, 37 (434), 717–724.
- Rees, C; Neilson, L. (2015). Demonstrating that colonoscopy is high quality. Endoscopy international open. Taken from: ncbi.nlm.nih.gov