Digestion, health and nutrition: Dr. Anil Minocha, a gastroenterologist and nutritionist

IRRITABLE BOWEL SYNDROME

Irritable bowel syndrome (IBS) or spastic colon affects 10-20 percent population. It is likely that you or someone you know has irritable bowel syndrome. But what is this irritable bowel syndrome or spastic colon or IBS?

Irritable bowel syndrome

IBS is a symptom based diagnosis of unclear etiology. It should not be confused with diverticulosis or diverticultis. Irritable bowel syndrome is probably is not a single disease. More likely, IBS is comprised of multiple diseases, all lumped into one at the present time for lack of understanding its pathogenesis. Infantile colic is considered by many to be a variant of IBS in infants and kids.

Features of irritable bowel syndrome and Rome criteria

Irritable bowel syndrome is a functional disorder characterized by chronic (at least three months in the preceding one year) abdominal pain and a disturbance of bowel habit. The disturbed bowel habit of IBS may manifest as diarrhea, constipation or alternating diarrhea with constipation. Pain frequently improves with defecation. A waxing and waning pattern of symptoms is seen in most patients. The precise conglomeration of symptom complex is defined under ROME III criteria.

What causes irritable bowel syndrome?

The pathogenesis of irritable bowel syndrome remains an enigma and no single etiology fits all cases. IBS is predominantly seen in young females but can be seen in adults of any age and either sex. It is more prevalent among Caucasian Americans than African Americans. Motility disorder has been frequently implicated; however no consistent motility pattern can be demonstrated. Visceral hypersensitivity (pain with a stimulus not severe enough to cause pain in healthy subjects) is seen in many patients. Autonomic dysregulation has also been implicated. A dysfunction of 5-HT system is supected in many cases. Stress does not cause it but does tend to exacerbate symptoms. Food allergy or intolerance may be present in some cases.

Many patients attribute the onset of disease to a bout of flu-like illness e.g. viral gastroenteritis, travelers diarrhea. Low grade inflammation in the gut can be documented in many cases. Several authors claim small intestinal bacterial overgrowth to be the cause in most cases of IBS although these observations have not been confirmed by others.

IBS consensus

Overall, in the absence of clear cut cause, a bio-psychosocial model for pathogenesis for irritable bowel syndrome has been proposed. This model emphasizes the role of mind-body interactions with the environment. In this context, it should be noted that there is an increased prevelance of certain chronic pain disorders in IBS patients, e.g. functional dyspepsia, fibromyalgia, chronic fatigue syndrome, interstitial cystitis, chronic back pain etc.

Diagnostic strategy for irritable bowel syndrome

While the diagnosis of irritable bowel syndrome should be positive, physicians frequently perform studies to exclude any treatable cause. The work up for IBS should be individualized and may include complete blood count (CBC), routine chemistries and stool studies. Flexible sigmoidoscopy or colonoscopy may be performed depending upon age and risk for colon cancer and suspicion for alternative diagnosis like inflammatory bowel disease (Crohn's disease and ulcerative colitis). Celiac sprue should be excluded by antibody testing for anti-tissue transglutaminase antibody. The use of anti-gliadin antibody has largely been abandoned.  Anti-endomysial antibody testing is expensive and not cost-effective. Lactose hydrogen breath test may be done to exclude lactose intolerance. Small bowel bacterial overgrowth can be excluded by hydrogen breath test or cultures of small bowel aspirate.

Treatment of irritable bowel syndrome

The management of IBS patients follows a step-wise fashion and is largely symptom based. Realistic goals need to be established. Reassurance with a lot of hand-holding goes a long way in helping patient cope with the symptoms of IBS. Placebo response rate in irritable bowel syndrome may be as high as fifty percent.  High fiber diet and fluid are frequently prescribed as first line of treatment for IBS of all types. Patients with diarrhea may be helped by lactose-avoidance.

Over the counter laxatives or  prescription medication Zelnorm are used in cases with constipation predominant IBS. Of note, Zelnorm was withdrawn from US market on March 30, 2007 because of unacceptable side-effects.

Constipating agents like Imodium and Lomotil may be needed in patients with diarrhea predominant IBS. Lotronex is useful for diarrhea-predominant IBS but has high risk for ischemic colitis. Its availability is limited and its use in IBS has largely been abandoned by most physicians in the US.  Its is not to be used for irritable bowel syndrome of constipation type. Antispasmodic agents e.g. Bentyl are frequently prescribed for abdominal pain associated with irritable bowel syndrome but provide only limited benefit at best.

Small bowel bacterial overgrowth is treated with antibiotics. Gluten-free diet helps patients with Celiac sprue.

Role of antidepressents in irritable bowel syndrome

Low dose tricyclic antidepressants (e.g. imipramine, desipramine) raise the pain threshold and are frequently prescribed to IBS patients not responding to above strategies; however their side-effects can be problematic.  Although frequently prescribed, there is less data about the use of newer antidepressant agents like SSRIs for management of IBS.

Several trials have documented positive impact of probiotics in IBS patients. Cognitive behavioral therapy, hypnosis, IBS classes, yoga, Chinese herbal medicine etc have  also been used successfully in irritable bowel syndrome. Limited data points to efficacy of melatonin (over-the-counter sleep-aid) in IBS.

Is melatonin useful in irritable bowel syndrome?

Irritable bowel syndrome continues to baffle the medical establishment because of lack of effective treatments. Now comes study suggesting that the naturally acting substance (melatonin) helps in ameliorating this vexing problem.

What is melatonin? It is a naturally occurring hormone in all living beings. It is synthesized in the brain (pineal gland), gastrointestinal system and retina from an amino acid tryptophan. In addition to its role in wake-sleep cycle, it is a powerful antioxidant, stimulator of immune system. It is sold over the counter as a natural sleep remedy.

Dr. Saha and colleagues from PGIMER in Chandigarh, India studied the role of melatonin in IBS patients. They published their findings in Journal of Clinical Gastroenterology (January 2007).

These investigators conducted a randomized controlled trial of the use of melatonin or placebo in 18 patients with IBS. They found that use of melatonin for 8 weeks significantly improved overall IBS score. The extracolonic IBS score was also significantly improved as compared with placebo. In addition, use of melatonin resulted in improvement in quality of life score to 43.63% as compared to 14.64% in placebo group.

Do you or someone you know has IBS? Do you find the currently available treatments effective? Have you ever used any natural remedies for anything including IBS?

Hypnosis for IBS: Does it work?

Irritable bowel syndrome (IBS) or spastic colon can be very difficult to treat in many patients. There is paucity of medications available, and many of the strategies used actually have not been shown to be of benefit. Hypnosis has been gaining a lot of attention lately for this vexing problem.

Dr. Roberts and colleagues from the University of Birmingham in United Kingdom conducted a randomized controlled trial to evaluate this hypnotherapy as a complementary therapy and published their data in the British Journal of General Practice (Feb 2006).

Patients with IBS who had failed conventional treatment were included in the study. Patients in the study group received five sessions of hypnotherapy in addition to their usual management. Usual and conventional treatment was administered to the control group.

These investigators found that after a period of 3 months, significantly greater improvements were seen in the intervention group. This included improvement in pain, diarrhea and overall symptom scores . Quality of life was not improved. While the improvement in symptoms was not maintained over long-term, the patients in study group were significantly less likely to require medication, and the majority felt that their condition had improved.

Do you or someone you know has IBS? What treatments have worked for you? What are your thoughts on hypnosis or other forms of complimentary and alternative medicine?

Gas, boating and distention in IBS

Pooling of gas within the digestive tract and difficulty moving it downstream to get rid of it has been implicated in production of bloating and abdominal discomfort including infantile colic. However, the part of bowel involved in intestinal gas retention has not been well defined.

Salvioli and colleagues from the University of Barcelona recently performed a study of small bowel reaction to infusion of fat into the intestine and published their findings in the American Journal of Gastroenterology (August 2006). These investigators studied six patients with irritable bowel syndrome and compared them to healthy controls.

The authors found that in patients with IBS, there is gas retention associated with abdominal distention and distress. They concluded that fat infusion into the bowel inhibits propulsion of gas in the small intestine via reflex inhibition of small bowel transit. This is not accompanied by any significant effects on the colon.

Based on these results and those of some other recent studies, it may be concluded that the origin of bloating and distention symptoms lies in the small intestine.

Do you or someone you know has gas problems? If so, what measures have you taken to feel better?