Irritable Bowel Syndrome (IBS) Dr. Mansour K. Alzahrani

Outlines Understand the hypothesis explain the pathphysiology of IBS. Common sign and symptoms Rome IV criteria of diagnosis Introduction to management of IBS

Definition Irritable bowel syndrome (IBS) is a chronic condition characterised by abdominal pain associated with bowel dysfunction.

Epidemiology Is it common? In US 10%-20% In UK 16.7% In china 5.7% In KSA 8.9%-9.2% Medical students 19.1 and 22.0% Female: Male 2:1

Etiology No specific endoscopic, biochemical, anatomic, microbiological, or histological findings in IBS that make the etiology clear. It is probably multi-factorial and evidence suggests motility, inflammatory, genetic, immune, psychological, and dietary components. Intestinal microbiota may play a role in functional bowel disease, including IBS. Stress and emotional tension frequently trigger bouts of IBS

Pathophysiology Altered GI motility: The myoelectric activity of the colon is composed of background slow waves with superimposed spike potentials. Colonic dysmotility in irritable bowel syndrome manifests as variations in slow-wave frequency and postprandial response of spike potentials.

Visceral hyperalgesia: Enhanced perception of normal motility and visceral pain characterizes irritable bowel syndrome. Patient with IBS feel pain at lower volumes.

Microscopic inflammation: Microscopic inflammation has been documented in some patients. infiltration of lymphocytes into the myenteric plexus Neuronal degeneration of the myenteric plexus was also present in some patients.

Alterations in the intestinal flora: Small bowel bacterial overgrowth has been heralded as a unifying mechanism for the symptoms of bloating and distention. The fecal microflora also differs among patients with irritable bowel syndrome versus controls in the patterns and the contents.

Psychopathology: Associations between psychiatric disturbances and irritable bowel syndrome pathogenesis are not clearly defined. Whether psychopathology incites the development of irritable bowel syndrome or vice versa remains unclear.

Classification 1. IBS with constipation (IBS-C): hard stools for ≥25% of bowel movements and loose for ≤25% of bowel movements. 2. IBS with diarrhoea (IBS-D): loose (mushy) ≥25% of bowel movements and hard stool for ≤25% of bowel movements. 3. Mixed IBS (IBS-M): hard stools for ≤25% and loose (mushy) or watery stools for ≤25% of bowel movements.

Diagnostic approach History : Risk factors Strong weak Physical or sexual abuse Age >50 Female gender Previous bacterial gastroenteritis weak Family and job stress

abdominal discomfort (common) alteration of bowel habits associated with pain (common) abdominal bloating or distension (common) normal examination of abdomen (common) passage of mucus with stool (uncommon)

Diagnostic tests Test Result FBC Normal, anemia suggests non-IBS disease Stool studies ( in diarrhea or bloating) normal., WBCs in stool or parasites suggest non-IBS disease Celiac disease antibodies ( diarrhea or weight loss) Negative, positive in celiac disease Abdominal X-ray ( bloating) Normal, abnormal in bowel obstruction Flexible sigmoidoscopy ( any patient >50) Normal, abnormal mucosa suggest IBD Colonoscopy ( if patient <50 or family hx of 1st degree relative >60 with colon cancer ) Normal, abnormal in IBD or neoplasm

Differential diagnosis: Crohn’s disease Ulcerative colitis Celiac disease Colon cancer Bowel infections

Diagnostic criteria Rome IV criteria: Recurrent abdominal pain or discomfort, on average at least 1 day per week in the last 3 months and associated with ≥2 of the following criteria: • Related to defecation • Associated with a change in frequency of stool • Associated with a change in form (appearance) of stool

Step-by-step treatment approach The main goal of treatment is to decrease the severity of the symptoms and improve quality of life. Pharmacological therapy is frequently used in IBS, good- quality evidence of efficacy is missing for most of the agents used.

Lifestyle and dietary modifications establish an effective therapeutic relationship provide education and reassurance. Initial treatments should be conservative, including discussion of lifestyle changes that may lessen stress. caffeine, lactose, or fructose, may need to be eliminated from the diet. Probiotics may also be considered (Bifidobacterium infantis) A diet low in FODMAPs has been shown to improve multiple symptoms including diarrhoea, flatus, bloating, and pain.

Pharmacological treatment Constipation Diarrhea Pain or bloating Fiber lopermide Antispasmodics (Dicyclomine or hyoscyamine) Laxetives Alosetron Peppermint oil lactulose Eluxadoline TCA or SSRI Linaclotide Cognitive behavior therapy

Summary Irritable bowel syndrome is a chronic condition characterised by abdominal pain associated with bowel dysfunction. The patient will typically have recurrent abdominal pain or discomfort that is associated with a change in stool frequency or form. The pain or discomfort may be relieved by defecation. It is important to determine whether there are any dietary associations.

Examination of the abdomen is usually unremarkable. There may be mild and poorly localized tenderness in the RLQ and/or LLQ. The diagnosis is based on the patient's history, and there are no specific diagnostic tests. If the patient has worrying symptoms or findings such as anaemia, weight loss, or fever, then these require more thorough investigation. Treatment should be individualised and is dependent on the patient's predominant symptoms

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