IRRITABLE BOWEL SYNDROME (IBS)

Definition ◦ Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by abdominal pain or discomfort and altered bowel habits in the absence of detectable structural ( organic ) abnormalities.

Pathophysiology of IBS ◦ The pathogenesis of IBS is poorly understood, although roles of ◦ abnormal gut motor and sensory activity, central neural dysfunction, ◦ psychological disturbances, mucosal inflammation, stress, and ◦ luminal factors have been proposed.

Epidemiology ◦ ➢ IBS is the most common cause of gastrointestinal referral and accounts for frequent absenteeism from work and impaired quality of life. ◦ ➢ Young women are affected 2–3 times more often than men. ◦ The people most commonly affected are those aged ◦ 20–30 years

The traditional focus has been on alterations in: - Gastrointestinal motility - Visceral hypersensitivity More recent studies have considered the role of inflammation, alterations in fecal flora, and bacterial overgrowth being considered is the role of food sensitivity, Whether a genetic tendency is also being investigated.

GASTROINTESTINAL MOTOR ABNORMALITIES ◦ Although the symptoms of irritable bowel syndrome (IBS) have focused attention on colonic motility, no predominant pattern of motor activity has emerged as a marker for IBS. However, motor abnormalities of the gastrointestinal tract (GI) are detectable in some patients with IBS.

*Studies of colonic myoelectrical and motor activity under unstimulated conditions have not shown consistent abnormalities in IBS. In contrast, colonic motor abnormalities are more prominent under stimulated conditions in IBS. IBS patients may exhibit increased rectosigmoid motor activity for up to 3 h after eating. *Abnormalities observed include increased frequency and irregularity of luminal contractions,prolonged transit time in constipation-predominant IBS and an exaggerated motor response to cholecystokinin and meal ingestion in diarrhea- predominant IBS.

However, pharmacologic stimulation of gut motility in IBS patients has been reported to reduce gas retention and improve symptoms, suggesting that a motility disturbance underlies this complaint in some patients.

VISCERAL HYPERSENSITIVITY ◦ Visceral hypersensitivity (increased sensation in response to stimuli) is a frequent finding in irritable bowel syndrome (IBS) patients. Perception in the gastrointestinal (GI) tract results from stimulation of various receptors in the gut wall. These receptors transmit signals via afferent neural pathways to the dorsal horn of the spinal cord and ultimately to the brain.

PROPOSED MECHANISMS FOR VISCERAL HYPERSENSITIVITY

Clinical features

5 MAIN CLINICAL FEATURES FOR IBS : Long term disease (chronic). Abdominal pain or discomfort. Abdominal bloating. Alteration of bowel habits. Gas and flatulence.

ABDOMINAL PAIN It is the most common presentation of IBS. Abdominal pain in IBS is highly variable in intensity and location. It is frequently episodic and crampy. Pain is often exacerbated by eating or emotional stress and improved by passage of flatus or stools. While in females, they report worsening symptoms during the premenstrual and menstrual phases.

ALTERED BOWEL HABITS The most common pattern is constipation alternating with diarrhea. At first, constipation may be episodic, but eventually it becomes continuous and increasingly intractable to treatment with laxatives. Most patients also experience a sense of incomplete evacuation, thus leading to repeated attempts at defecation in a short time span. In other patients, diarrhea may be the predominant symptom. Diarrhea resulting from IBS usually consists of small volumes of loose stools.

Diarrhea -During the daytime, very unusual to occur during sleep (most often in the morning or after meals) -Extreme urgency -Feeling of incomplete emptying -Associated with mucus in ½ of patients Constipation -Stools are often hard -Pellet-shaped -Feeling of incomplete emptying

GAS AND FLATULENCE Patients with IBS frequently complain of abdominal distention and increased belching or flatulence, all of which they attribute to increased gas. Some patients with bloating may also experience visible distention with increase in abdominal girth. Both symptoms are more common among female patients.

NON-GASTROINTESTINAL SYMPTOMS GU symptoms : -Urinary urgency. -Polyuria. -Nocturia. -Incontinence. -Dysmenorrhoea. -Dyspareunia. -Poor libido.

Other symptoms : -Fatigue. -Back pain. -Bad breath, unpleasant tast in the mouth. -Poor sleeping. -Dyspepsia. -Heartburn. -Nausea. -Vomiting.

Physical examination

The patient with irritable bowel syndrome has an overall healthy appearance but may be tense or anxious. The patient may present with sigmoid tenderness or a palpable sigmoid cord.

SOME FACTORS THAT CAN TRIGGER ONSET OF IRRITABLE BOWEL SYMPTOMS Affective disorders, e.g. depression, anxiety. Psychological stress and trauma. Gastrointestinal infection. Antibiotic therapy. Sexual, physical, verbal abuse. Pelvic surgery. Eating disorders.

DIAGNOSIS

Criteria for making a diagnosis researchers have developed two sets of diagnostic criteria for IBS,, Both criteria are based on symptoms after other conditions have been ruled out. 1.Rome criteria 2.Manning criteria.

Rome criteria There are certain signs and symptoms,The most important are abdominal pain and discomfort lasting at least three days a month in the last three months, associated with two or more of following: improvement with defecation, altered frequency of stool or altered consistency of stool.

Manning criteria These criteria focus on pain relieved by defecation, having incomplete bowel movements, mucus in the stool and changes in stool consistency. The more symptoms present, the greater the likelihood of IBS.

There are Some red flag signs and symptoms that suggest a need for additional testing include: 1.New onset after age 50 2.Weight loss 3.Rectal bleeding 4.Fever 5.Nausea or recurrent vomiting 6.Abdominal pain, especially if it's not completely relieved by a bowel movement, or occurs at night 7.Diarrhea that is persistent or awakens you from sleep 8.Anemia related to low iron

Additional tests Imaging tests: 1.Flexible sigmoidoscopy 2.Colonoscopy, In some cases, especially if you are age 50 or older or have other signs of a potentially more serious condition, 3. X-ray (radiography). 4. Computerized tomography (CT) scan. 5.Lower GI series, In this test, doctors fill your large intestine with a liquid (barium) to make it easier to see any problems on the X-ray.

Laboratory tests: 1.Lactose intolerance test 2.Breath tests : Your doctor may perform a breath test to look for a condition called bacterial overgrowth, in which bacteria from the colon grow up into the small intestine, leading to bloating, abdominal discomfort and diarrhea. 3.Blood tests. 4.Stool tests.

TREATMENT

treatment focuses on the relief of symptoms so that you can live as normally as possible. In most cases, you can successfully control mild signs and symptoms of irritable bowel syndrome by Try to avoid foods that trigger your symptoms. Also try to get enough exercise, drink plenty of fluids and get enough sleep.

1. Dietary changes: Eliminating high-gas foods: If you have bothersome bloating or are passing considerable amounts of gas, doctor may suggest that you cut out such items as carbonated beverages, vegetables — especially cabbage, broccoli and cauliflower — and raw fruits. Eliminating gluten. Research shows that some people with IBS report improvement in diarrhea symptoms if they stop eating gluten (wheat, barley and rye).

Eliminating FODMAPs: Some people are sensitive to types of carbohydrates such as fructose, fructans, lactose and others, called FODMAPs (fermentable oligo-, di-, and monosaccharides and polyols). FODMAPs are found in certain grains, vegetables, fruits and dairy products.

2. Medications: Fiber supplements: Taking fiber supplements, such as psyllium (Metamucil) or methylcellulose (Citrucel), with fluids may help control constipation. Anti-diarrheal medications: Over-the-counter medications, such as loperamide (Imodium), can help control diarrhea. Some people will benefit from medications called bile acid binders, such as cholestyramine (Prevalite), colestipol (Colestid) or colesevelam (Welchol), but these can lead to bloating.

● Anticholinergic and antispasmodic medications: These medications, such as hyoscyamine (Levsin) and dicyclomine (Bentyl), can help relieve painful bowel spasms. They should also be used with caution among people with glaucoma. ●Antidepressant medications: If your symptoms include pain or depression, your doctor may recommend a tricyclic antidepressant or a selective serotonin reuptake inhibitor (SSRI). These medications help relieve depression as well as inhibit the activity of neurons that control the intestines.

Antibiotics ◦ Some people whose symptoms are due to an overgrowth of bacteria in their intestines may benefit from antibiotic treatment. ◦ Some people with symptoms of diarrhea have benefited from rifaximin (Xifaxan).

Medication specifically for IBS 1- Alosetron (Lotronex). Alosetron is designed to relax the colon and slow the movement of waste through the lower bowel. Alosetron can be prescribed only by doctors enrolled in a special program and is intended for severe cases of diarrhea-predominant IBS in women who haven't responded to other treatments. Alosetron is not approved for use by men. It has been linked to rare but important side effects, so it should only be considered when other treatments are not successful.

2- Lubiprostone (Amitiza). Lubiprostone works by increasing fluid secretion in your small intestine to help with the passage of stool. It is approved for women age 18 and older who have IBS with constipation. Its effectiveness in men is not proved, nor its long-term safety. Common side effects include nausea, diarrhea and abdominal pain. Lubiprostone is generally prescribed only for women with IBS and severe constipation for whom other treatments haven't been successful.

3.Lifestyle and home remedies 1.Experiment with fiber 2.Avoid problem foods 3.Eat at regular times 4.Take care with dairy products 5.Drink plenty of liquids 6.Exercise regularly

References 1- Davidson’s principles and practice of medicine, 21st edition: , Kumar and Clark's Clinical Medicine, 7th edition: , Harrison's Principles Of Internal Medicine, 18th edition: , overview 5- syndrome-beyond-the-basics

Done by : Nour Hamdan Jumana Al Rajabi Noujoud Al Jondi