Since there’s been no identifiable cause to point out and laboratory tests are inconclusive, there are lots of theories that attempt to clarify the disruption within the body in individuals with IBS. Many of these hypotheses are based on abnormalities inside the transit system of the abdominal cavity through the remainder of the bowel (intestine, colon), hypersensitivity (notably to pain), and psychological variables.
The Case for Abnormal Movement
Various studies have been done which evaluate colon function in normal persons to people struggling with IBS. Some of those studies have revealed that there’s a variation in patients with IBS and people which don’t have IBS in the colon’s reaction to meals. These studies demonstrated a pattern of abnormal colonic movements in IBS sufferers more related to diarrhea. It’s indicated that electrical activity inside the intestines is abnormal, leading to abnormal stimulation of the colonic walls.
In the small intestine, unusual motion patterns, when slowed or delayed, trigger constipation in those more likely to obtain this kind (constipation-predominant IBS) and when the motions are accelerated, it causes diarrhea (diarrhea-predominant IBS).
The Case for Hyper-Responsiveness
Various other theories indicate that the disorder is in the muscles of small and large intestines themselves and that there’s a hyper-responsiveness to regular stimulus. So some folks believe the problem lies with unusual electrical activity and the others suggest the electrical activity inside the intestines is good, the problem lies with all the intestinal smooth muscles being hyper-responsive. People who think that smooth muscles are the issue point to other difficulties like bladder dysfunction, which is found in 50% of patients with IBS but not nearly as much in those without IBS (13%).
The Case for Hyper-Sensitivity
Some experts think the issue is with the hyper-sensitivity to pain some patients with IBS experience. Medical research have showed that inflating the colon close to the rectum stimulates pain at a lower threshold than regular patients. In other words, someone with IBS will feel pain sensations before an individual without IBS does. In addition, individuals with IBS describe dermatomal (or regional) distribution of pain. It is thought the hypersensitivity is a result of neurons (nerve cells) within the spinal cord which are hyper-excitable.
The Case for Psychiatric Issues
There’s lots of interaction between the mind and the intestines. There are lots of neurotransmitters within the mind and along the gut. These transmitters are significant in determining: 1) how food passes within the GI tract, 2) controlling pain, 3) controlling emotions, and 4) affirming immunity. If this axis (CNS-gut) doesn’t function correctly, the symptoms of IBS could be viewed.
Even though it is not proven that psychiatric difficulties cause IBS, it’s well-documented that IBS is discovered to become more common in individuals with psychiatric problems. These individuals have more relapses and worse illnesses. The psychiatric disorders commonly connected with IBS include major depression, anxiety disorders, stress disorders, and personality problems. These problems aren’t considered to cause IBS but instead change the individual’s view of their sickness.
Anxiety and stress often result in GI issues, and in fact 77% of patients diagnosed with a psychiatric Axis I disorder have disturbances with their gastrointestinal capabilities. In addition, it has been noted that individuals whom have a history of physical abuse or rape have increased prevalence of IBS. Study continues currently to determine if IBS leads to the psychiatric disturbance or if the psychiatric difficulties lead to IBS.