Dr. Firdous Jahan
Assistant Professor, Family Medicine Dept.
Aga Khan University Hospital, Karachi, Pakistan

Correspondence:
Email: firdous.jahan@aku.edu

IBS is a chronic, relapsing gastrointestinal problem, characterized by abdominal pain, bloating, and changes in bowel habit.(1) While the precise prevalence and incidence depends on the criteria used, all studies agree that it is a common disorder, affecting a substantial proportion of individuals in the general population and presenting frequently to general practitioners and to specialists.(2) IBS is troublesome, with a significant negative impact on quality of life and social functioning in many patients.(3,4) IBS generates significant health care costs. Approximately two thirds of IBS patients referred to secondary care show some form of psychological distress, most commonly anxiety. Diagnosing a patient who presents with abdominal pain and altered bowel habits can be challenging.(5) IBS also accounts for a significant number of visits to primary care physicians and is the second highest cause of absenteeism after the common cold. Approaches to managing IBS should be informed by psychological understanding, recognizing that the most important aspect of management is the relation between the patient and the physician.(6,7) Patients with IBS managed in primary care comprise the entire spectrum, from those with mild or ill defined symptoms to those with severe or persistent problems. The mind and body often combine to increase the misery of IBS patients.(8)

Normal motility, or movement, may not be present in the colon of a person who has IBS. It can be spasmodic or can even stop working temporarily. The lining of the colon, which is affected by the immune and nervous systems, regulates the flow of fluids in and out of the colon. When the contents inside the colon move too quickly, the colon loses its ability to absorb fluids. The result is too much fluid in the stool. In others, the movement inside the colon is too slow, which causes extra fluid to be absorbed. As a result, a person develops constipation. (9) A person's colon may respond strongly to stimuli such as certain foods or stress that would not bother most people. Small-bowel motor dysfunction with concomitant gastro paresis occurs more frequently in patients with IBS. Serotonin is a neurotransmitter, or chemical, that delivers messages from one part of the body to another. (10) People with IBS, however, have diminished receptor activity, causing abnormal levels of serotonin to exist in the GI tract. Stimulation of various chemo receptors and mechanoreceptors in the gut wall transmit signals via afferent neural pathways to the dorsal horn of the spinal cord and ultimately to the brain .(11,28)

IBS may be caused by a bacterial infection in the gastrointestinal tract. Studies show that people who have had gastroenteritis sometimes develop IBS, otherwise called post-infectious IBS. The development of irritable bowel syndrome following infectious enteritis has been suspected clinically based upon a history of an acute diarrheal illness preceding the onset of irritable bowel symptoms in some pathogens included Escherichia coli O157:H7 and Campylobacter jejuni.(13) In severe infection, disruption of mucosal nerves may lead to irritability development of idiopathic bile acid malabsorption and increase in entero endocrine cells, T lymphocytes, and gut permeability has been demonstrated following acute Campylobacter enteritis, these changes persist for more than one year. Antibiotics may develop diarrhea related to alteration in colonic flora which will lead to reduced disaccharidase activity resulting in malabsorption of dietary sugars. Occult inflammatory bowel disease may have developed following infection. Microbes such as Lactobacillus strains may regulate immune responses directly in the host. Selective deficiencies of intestinal lactobacilli and bifidobacteria have been described in patients with Crohn's disease and IBS.(12)

IBS is generally diagnosed on the basis of a complete medical history that includes a careful description of symptoms and a physical examination.(14) Relevant history includes change in frequency of bowel movements, a change in appearance of bowel movements, feelings of uncontrollable urgency to have a bowel movement, difficulty or inability to pass stool, mucus in the stool and bloating. The following have been associated with a worsening of IBS symptoms: large meals, bloating from gas in the colon, medicines ,wheat, rye, barley, chocolate, milk products, alcohol drinks, caffeine, such as coffee, tea, or colas, stress, conflict, or emotional upsets. Women with IBS may have more symptoms during their menstrual periods, suggesting that reproductive hormones can worsen IBS problems.(12) Drinking carbonated beverages, such as sodas, may result in gas and cause discomfort. Chewing gum and eating too quickly can lead to swallowing air, which also leads to gas.(15,16)

In addition, people with IBS frequently suffer from depression and anxiety, which can worsen symptoms. (17) Similarly, the symptoms associated with IBS can cause a person to feel depressed and anxious. Stress, feeling mentally or emotionally tense, troubled, angry, or overwhelmed, can stimulate colon spasms in people with IBS.(18) The colon has many nerves that connect it to the brain. Like the heart and the lungs, the colon is partly controlled by the autonomic nervous system, which responds to stress. These nerves control the normal contractions of the colon and cause abdominal discomfort at stressful times .(19)

Although psychiatric illness often coexists with IBS, a clear causal relationship has not been shown. IBS might be a precursor to psychiatric illness; anxiety, major depression, panic disorder, social phobia, somatization disorder, and dysthymia have been identified in more than 50 percent of patients with IBS. IBS is more common in patients who abuse alcohol and in patients who have experienced physical or sexual abuse.(12) Many patients with IBS had stressful life events, such as divorce or a death in the family, before they developed symptoms. IBS among patients with chronic fatigue syndrome, fibromyalgia, and temporomandibular joint pain syndrome are high.(20,21)
To date, no gold standard or marker for IBS exists. A cost-effective diagnostic approach that uses the fewest tests and invasive studies is most desirable. As in all illnesses, the most valuable initial tools are a detailed history and physical examination. If alarm symptoms that suggest an underlying organic disease are uncovered, further testing usually is considered.(22) Scoring methods, subgroup classifications, laboratory studies, endoscopy, and psychiatric assessment are available to help guide the diagnosis in patients who present with abdominal pain. Several scoring systems for diagnosing IBS have been proposed. These scoring systems, which still are being validated, are useful for research and can help guide the diagnostic evaluation. The Rome III Criteria are the current standard for this definition. (23)

The Rome diagnostic criteria of Irritable Bowel Syndrome always presumes the absence of a structural or biochemical explanation for the symptoms and is made only by a physician.
Irritable Bowel Syndrome can be diagnosed based on at least 12 weeks (which need not be consecutive) in the preceding 12 months, of abdominal discomfort or pain that has two out of three of these features:

1. Relieved with defecation; and/or
2. Onset associated with a change in frequency of stool; and/or
3. Onset associated with a change in form (appearance) of stool.

Symptoms that Cumulatively Support the Diagnosis of IBS:
Abnormal stool frequency (may be defined as greater than 3 bowel movements per day and less than 3 bowel movements per week);abnormal stool form (lumpy/hard or loose/watery stool); abnormal stool passage (straining, urgency, or feeling of incomplete evacuation); passage of mucus; bloating or feeling of abdominal distension.

Patient subgroups (constipation-predominant, diarrhea-predominant, and pain-predominant), can be clinically useful IBS-----D (diarrhea),IBS-----C (constipation), IBS-----M (mixed), IBS-----A (alternator).(12)

Red Flag symptoms which are NOT typical of IBS are pain that often awakens/interferes with sleep, diarrhea that often awakens/interferes with sleep, blood in stool (visible or occult), weight loss, fever, abnormal physical examination, anemia, chronic severe diarrhea and family history of colon cancer. Patients with alarm features should undergo the appropriate endoscopic, stool, and radiologic testing and referral to gastroenterologist.(24)

Many illnesses share some of the same symptoms as IBS. Some of these illnesses are serious and require aggressive evaluation and treatment. Differential diagnosis for patients who present with abdominal pain and altered bowel habits are celiac disease, colitis, Giardiasis, lactose/bile salt malabsorption, tropical sprue, small bowel bacterial over growth, carcinoma of the colon.(25)
Extra intestinal symptoms include impaired sexual function, dysmenorrhea, dyspareunia, and increased urinary frequency and urgency. They are also more likely to have hypertension, reactive airway disease, and rheumatologic syndromes, including fibromyalgia, non cardiac chest pain.(26,27)

Laboratory Tests: Most authors suggest that all symptomatic patients should have a complete blood cell count. Determination of the erythrocyte sedimentation rate, thyroid-stimulating hormone (TSH) level, and electrolyte levels. Fecal occult blood testing and the testing of stool for ova and parasites are useful in patients with diarrhea. Lactose-malabsorption studies have limited value except in patients with diarrhea-predominant symptoms. Second line investigations includes routine flexible sigmoidoscopy and biopsy, lactose breath hydrogen test, Endomyseal antibody, tissue Transglutaminase antibody.(12)

Management in Primary care:
A caring doctor-patient relationship is the first step in management.

Explaining the diagnosis should be followed by reassurance as there is no single etiology and patients visit the physician with recurring symptoms.(28)

Avoiding aggravating factors including certain drugs and diet.

The treatment plan is based on the nature and severity of the symptoms, the degree of functional impairment, and the presence of psychosocial factors .Because of its safety and low cost, a trial of fiber is reasonable; particularly in patients whose predominant symptom is constipation.(29)
At low dosages, tricyclic antidepressants (TCAs) and, potentially, selective serotonin reuptake inhibitors (SSRIs) have analgesic properties independent of their effect on mood. The anti cholinergic properties of TCAs may slow intestinal transit time, making them effective in the treatment of diarrhea. Fiber supplements or laxatives for constipation or medicines decrease diarrhea, such as loperamide .(12) An antispasmodic is commonly prescribed, which helps to control colon muscle spasms and reduce abdominal pain. However, both antispasmodics and antidepressants can worsen constipation. Medications affect people differently, and no one medication or combination of medications will work for everyone with IBS.(12,30)

Probiotics are live microbial food supplements or components of bacteria that alter the enteric micro flora. The most frequently used genera are Lactobacilli and Bifidobacteria. The potential mechanisms of their action include competitive bacterial interactions, production of antimicrobial metabolites, mucosal conditioning, and immune modulation.(31)

Peppermint leaves contain oils that have mild anesthetic properties, relieve nausea, and relax smooth muscle spasticity caused by histamine and cholinergic stimulation. The herb ginger has one component, gingerois, which functions as a serotonin 5-HT antagonist and enhances motility. Aloe Vera has been recommended for constipation-dominant IBS. Fennel has been recommended for IBS-related bloating.(32,33)

A variety of psychotherapies, including cognitive behavior therapy, hypnosis, and stress management/relaxation therapy, reduce abdominal pain and diarrhea.(34) Relaxation technique is the process, procedure, or activity that helps a person to relax, including autogenic training, biofeedback, deep breathing, meditation, progressive muscle relaxation, visualization, yoga and hypnosis.(35) Stress management is an important part of treatment for IBS. Frequent and regular meditation and relaxation, even if only for a few minutes a day, does four things that are helpful in a stress-reducing program: it trains the attention, increases control over thought processes, increases the ability to handle emotions and aids physical relaxation. Physical activity is a way of responding to stress which allows the discharge of the energy the body is anticipating. Physical activity can be taken in many ways, including activities such as walking, jogging or sport.(36)

Progressive muscle relaxation teaches patients to relax muscles through a two-step process, first deliberately apply tension to certain muscle groups, and then stop the tension and turn your attention to noticing how the muscles relax as the tension flows away. Cognitive therapy seeks to help the patient overcome difficulties by identifying and changing dysfunctional thinking, behavior, and emotional responses. Identified "problem cycle," and the efforts of the therapist and patient would be directed at working together to change it and also address the way the patient thinks and behaves in response to similar situations and by doing develop more flexible ways to think and respond .(37) The patient may then become more active, succeed and respond more adaptively more often, and further reduce or cope with his negative feelings.

The mind and body often combine to increase the misery of IBS patients. Psychological interventions including cognitive behavioral therapy, hypnotherapy and relaxation techniques are worth considering. A great majority of IBS patients can be managed well by Family Physicians .(37,38) Awareness of 'red flags' for referral to a specialist gastroenterologist is a must. If handled properly, stress can help improve performance, but too much stress without appropriate strategy to control it can be harmful for the mind and the body.(39,40) Given the limited benefits of pharmacologic therapy and the psychosocial issues involved, effective treatment of IBS requires a comprehensive, multifaceted approach.(41,42)