User:Gastro guy/ibs notes

Medical conditions that accompany IBS
Researchers have identified several medical conditions, or comorbidities, which appear with greater frequency in patients diagnosed with IBS.


 * Headache, Fibromyalgia, and Depression:A study of 97,593 individuals with IBS identified comorbidities as headache, fibromyalgia, and depression.  Fibromyalgia has also been identified in other studies as a co-morbidity of IBS.


 * Inflammatory Bowel Disease: Some researchers have suggested that IBS is a type of low-grade inflammatory bowel disease. Researchers have suggested that IBS and IBD are interrelated diseases, noting that patients with IBD experience IBS-like symptoms when their IBD is in remission.  A 3-year study found that patients diagnosed with IBS were 16.3 times more likely to develop IBD during the study period.  Serum markers associated with inflammation have also been found in patients with IBS (see Causes).


 * Endometriosis: One study has reported a statistically significant link between migraine headaches, IBS, and endometriosis.

IBS as a psychosomatic illness (1950- ~2000)


Most peptic ulcers are now treated with 1-2 weeks of antibiotic therapy, since it has been discovered that they are caused by a combination of a genetic trait in the patient and infection with the bacteria H. Pylori.

One of the first references to the concept of an "Irritable Bowel" appeared in the Rocky Mountain Medical Journal in 1950. The term was used to categorize patients who developed symptoms of diarrhea, abdominal pain, constipation, but where no well-recognized infective cause can could be found. Early theories suggested that the Irritable Bowel was caused by a somatic, or mental disorder. One paper from the 1980's investigated "learned illness behavior" in patients with IBS and peptic ulcers. Another study suggested that both IBS and peptic ulcer patients would benefit from 15 months of psychotherapy.

Additional publications suggesting the role of brain-gut "axis" appeared in the 1990's. A 1997 study published in Gut magazine described the "derailing of the brain-gut axis" in association with IBS.

Discovery of inflammation and secretory changes (1997- )
In the late 1990's and later, research publications began identifying specific biochemical changes present in tissue biopsies and serum samples from IBS patients, suggesting that the symptoms of IBS may have an organic rather than psychosomatic cause. These studies identified cytokines and secretory products in tissues taken from IBS patients. Cytokines are chemicals produced by the body to perform communication between cells. The cytokines identified in IBS patients are inflammatory cytokines which are associated with the body's immune response.


 * A 1997 study of blood samples from IBS patients published in the American Journal of Tropical Medicine and Hygiene found elevated levels antibodies to the protozoan Blastocystis.


 * A 2001 study published in Digestion from the International Medical University (Japan) showed that intestinal biopsies from patients with constipation predominant IBS secreted higher levels of serotonin in-vitro. Serotonin controls smooth muscle contraction in the body, and many other functions.  Serotonin is secreted by some gastrointestinal protozoa, causing diarrhea and elevated serum serotonin levels in humans.


 * A 2003 study of rectal biopsy tissue from IBS patients performed at the National University, Singapore and published in Gut magazine showed increased levels of cellular structures involved in the production of the inflammatory cytokine IL-1 Beta.


 * A 2007 study of blood samples from IBS patients performed at the University of Adelaide and published in Gastroenterology identified elevated levels of cytokines TNF-Alpha, IL-1, and IL-6 in patients with IBS.


 * A 2007 study of intestinal biopsies from IBS patients performed at the University of Calgary and published in the Journal of Clinical Investigation showed increased levels of protease secretion. Proteases are chemicals which split proteins into smaller molecules.  The human body uses them to digest proteins, and they are also used by infectious diseases to combat the host's immune system.

Identification of active infections (2003- )
Some researchers believe IBS may be caused by an active infection which has not yet been discovered. Many clinically significant gastrointestinal pathogens have been discovered in the last 50 years, and medical recognition has taken decades in some cases (see History of emerging infectious diseases). Most recently, a study has found that the antibiotic Rifaximin provides sustained relief for IBS patients.



Some physicians retain the view that no infectious cause exists, and suggest that IBS patients have too much bacteria in their intestines and the antibiotics reduce the amount of bacteria. This theory is known as SIBO (Small Intestinal Bacterial Overgrowth).

Protozoal Infections
Protozoa are single-celled organisms which can cause symptoms equivalent to IBS. Several researchers have focused on unrecognized protozoal infection as a cause of IBS because of this, and because some protozoal infections occur at a statistically significant rate in IBS patients. The two protozoa investigated have a high prevalence in industrialized countries, infect the bowel, but are recently emerged pathogens so little is known about them.

Blastocystis is a single-celled organism which has been reported to produce symptoms of abdominal pain, constipation and diarrhea in patients, along with headaches and depression. Researchers have noted that existing methods may fail to diagnose infection properly, and it may not respond to treatment with common antiprotozoals. The following reports have linked Blastocystis infection to IBS:


 * A study of IBS patients in the Middle East found 43% were infected with Blastocystis vs. 7% of healthy controls..
 * An additional study of IBS patients in the Middle East showed a "significantly increased" immune reaction in IBS patients to Blastocystis, even when the organism could not be identified in stool samples.
 * A European study compared Blastocystis infection rates in IBS patients to those of healthy controls and found a statistically significant infection rate in IBS patients.
 * Early reports from the US physicians in the 1980's suggested the presence of the organism was not relevant to the diagnostic process, and patients infected with Blastocystis could be diagnosed with IBS.



Since the 1980's, researchers have found multiple types of Blastocystis infect humans, and some types cause disease while others do not, possibly explaining conflicting reports of physicians. Three studies of experimental infection of animals with Blastocystis report fulfilling Koch's Postulates, a widely accepted criteria for establishing the ability of an organism to cause disease.

Dientamoeba fragilis is a single-celled organism which produces abdominal pain and diarrhea. Studies have reported a high incidence of infection in developed countries, and symptoms of patients resolve following antibiotic treatment. One study reported on a large group of patients with IBS-like symptoms who were found to be infected with Dientamoeba fragilis, and experienced resolution of symptoms following treatment. Researchers have noted that methods used clinically may reliably detect infection with Dientamoeba fragilis.