RCSI Irritable Bowel Syndrome Presentation PDF

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Irritable Bowel Syndrome Department of Medicine LEARNING OUTCOMES 1. Define irritable bowel syndrome 2. List the causes of irritable bowel synd...

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Irritable Bowel Syndrome Department of Medicine LEARNING OUTCOMES 1. Define irritable bowel syndrome 2. List the causes of irritable bowel syndrome 3. Describe how each cause leads to the development of IBS 4. Outline the common symptoms and signs in IBS 5. Develop a differential diagnosis for IBS 6. Outline the overarching principles of investigations and management in IBS LEARNING OUTCOME 1 Define irritable bowel syndrome IRRITABLE BOWEL SYNDROME (IBS) A chronic disorder of the gastrointestinal system characterised by recurrent abdominal pain and altered bowel habits. It can be associated with abdominal bloating and the pain is often relieved by defecation. This is a functional condition, so no organic or structural abnormality can be identified for the symptoms. It occurs in about 15% of the adult population and is the commonest cause for gastroenterology referral LEARNING OUTCOME 2 List the causes of irritable bowel syndrome IBS SUBTYPES AETIOLOGY The aetiology of IBS is unclear, but it is thought to be multi-factorial. Evidence suggests factors such as motility, visceral hypersensitivity, inflammatory, genetic, immune, psychological, and dietary components may play a role. LEARNING OUTCOME 3 Describe how each cause leads to the development of IBS PATHOPHYSIOLOGY Inflammatory or immune system involvement – IBS can sometimes occur in conjunction with inflammatory bowel disease and can sometimes develop after a bout of bacterial or parasitic gastroenteritis. Thus it is hypothesised that an inflammatory or immune component to IBS exists. – Some patients with IBS have been found to have increased gut wall T- lymphocytes and mast cells and increased plasma pro- inflammatory cytokines PATHOPHYSIOLOGY Motility – Motor abnormalities are observed in some patients with IBS. These include increased frequency and irregularity of bowel contractions and prolonged transit time in constipation- predominant IBS. Visceral Hypersensitivity – Studies show that patients with IBS have a heightened sensitivity to normal gut wall receptor stimulation. For example, they have an increased awareness of pain and bloating in response to bowel distension. PATHOPHYSIOLOGY Alteration in intestinal microflora – IBS appears to be associated with an imbalance and reduced diversity in the intestinal microbiome. – This is likely due to the actions of microflora on certain foods, particularly carbohydrates, and also their importance in epithelial barrier integrity and enteroendocrine signalling. Bacterial overgrowth – IBS is thought to be associated with increased numbers and/or types of bacteria in some patients, especially diarrhoea- predominant IBS. PATHOPHYSIOLOGY Genetic – Familial studies and studies on select gene polymorphisms, for example the serotonin transporter gene, suggest a genetic susceptibility in some patients with IBS. Psychological stress or abuse – Bouts of IBS are often triggered by states of stress and increased emotional tension. There is also and increased likelihood of IBS in patients with a history of physical or sexual abuse and PTSD. LEARNING OUTCOME 4 Outline the common symptoms and signs in IBS CLINICAL MANIFESTATIONS Symptoms Signs Chronic recurrent Rarely mucus in stools abdominal pain (cramping, Typically, will have a typically lower or mid- normal abdominal abdomen) examination (may have Constipation mild lower abdominal Diarrhoea tenderness) Bloating Abdominal distension Urgency of defaecation ABSENCE OF ANY RED FLAG SYMPTOMS LEARNING OUTCOME 5 Develop a differential diagnosis for IBS DIFFERENTIALS Crohn’s: – Abdominal cramps, diarrhoea, rectal bleeding, weight loss, fevers, fatigue, possible mass in RLQ on abdominal exam, oral ulcers Ulcerative colitis: – Bloody diarrhoea, abdominal pain, urgency, extra-intestional e.g. arthropathy, erythema nodosum etc. Coeliac disease: – Abdominal bloating, pain and diarrhoea precipitated by gluten consumption, unintentional weight loss and early osteoporosis due to malabsorption Colorectal cancer (CRC): – Unintentional weight loss, altered bowel habit, melena, hematochezia, nocturnal diarrhoea Infectious gastroenteritis (parasitic or bacterial) LEARNING OUTCOME 6 Outline the overarching principles of investigations and management in IBS DIAGNOSIS IBS should be suspected in patients with IBS symptoms particularly chronic abdominal pain and altered bowel habits (and bloating, abdominal distention, urgency). IBS is a clinical diagnosis and requires the fulfillment of symptom-based diagnostic criteria and exclusion of underlying organic disease.  l The presence of any of these warning signs may suggest an alternative diagnosis DIAGNOSIS (INVESTIGATIONS USED TO EXCLUDE OTHER PATHOLOGIES BASED ON SYMPTOMS AND RISK FACTORS) Blood tests FBC- should be normal in IBS, anaemia (CRC or malabsorption syndrome) or elevated WBC (Inflammatory bowel disease; IBD) suggests another aetiology ESR/CRP- should be normal, if elevated possible IBD or infectious aetiology Serology testing for coeliac disease- positive anti-tissue transglutaminase or IgA endomysial antibodies DIAGNOSIS Stool tests Faecal occult blood- may be positive in CRC or IBD Faecal calprotectin/faecal lactoferrin- elevated in IBD; calprotectin has superior clinical utility Stool test for bacteria and parasites DIAGNOSIS Imaging PFA: Plain film abdominal x-ray- distended bowel loops of bowel in obstruction CT abdomen/pelvis- may show complications of Crohn’s (abscess, strictures, adhesions etc.) or CRC Others OGD/colonoscopy- if IBD/Coeliac/CRC is suspected Histology: normal duodenal mucosa on left, coeliac on right- villous Colonoscopy: atrophy PFA: dilated small bowel ulceration/skip lesions in loops Crohn's MANAGEMENT (NON-PHARMACOLOGICAL 1 ST LINE)  Reassurance  Dietary modifications Avoidance of high FODMAP foods Avoidance of gas producing foods Insoluble fibre avoidance e.g. bran Gluten avoidance Lactose avoidance  Additional Cognitive behavioural therapy Hypnotherapy Acupuncture Yoga FODMAP FOODS Fermentable Oligosaccharides – few simple sugars linked together (fructans, galactans) Disaccharides – double sugar (lactose) Monosaccharides – single sugar (fructose) And Polyols – sugar alcohols (sorbitol, mannitol, isomalt, xylitol, glycerol) MANAGEMENT (PHARMACOLOGICAL) Abdominal pain and bloating Anti-spasmodics- mebeverine, dicyclomine, peppermint oil Antidepressants - TCAs e.g. amitriptyline, nortriptyline (IBS-D). Significant side-effects, not first line. Antibiotics- rifaximin Probiotics (not routinely recommended but associated with improved symptoms in some patients) MANAGEMENT (PHARMACOLOGICAL) Constipation (IBS-C) Soluble fibre- eg. psyllium/ispaghula Osmotic laxatives: Lactulose: MOA: non- absorbable synthetic sugar Colonic metabolism of sugars causes a laxative effect via an increase in intraluminal gas formation and osmolality which leads to a reduction in transit time. Increased uptake of ammonia by colonic bacteria which utilize the trapped colonic ammonia as a nitrogen source for protein synthesis. **Role in hepatic encephalopathy via reduction of ammonia** Side effects: Flatulence, abdominal pain, diarrhoea, nausea and vomiting. Macrogol: Polyethylene glycol (PEG) Forms hydrogen bonds with water molecules preventing their absorption, leading to more water in stool making it easier to pass. Associated with less flatulence and cramping than other osmotic laxatives Stimulant laxatives: eg Sennakot, Bisacodyl Irritate luminal nerves, stimulating colonic motility. Helps to stimulate movement of stool, but does not soften to the same degree as osmotics, therefore recommended to be used as an adjunct to stool softeners Caution: may contribute to bowel perforation in intestinal obstruction Secretagogues: lubiprostone, linaclotide, plecanatide, or tenapanor Increase fluid secretion and movement in the GIT MANAGEMENT (PHARMACOLOGICAL) Diarrhoea (IBS-D) Anti-diarrhoeal- loperamide (only once infectious cause out ruled!) Bile acid sequestrants- cholestyramine Opioid agonists/antagonists- e.g. eluxadoline (preferred opioid for pain control in IBS-D as has less constipating adverse effect)  1 2 3 4 5 6 7 8 A 32-year-old female presents to her primary care physician with complaints of recurrent abdominal pain, bloating, flatulence and constipation. She mentions that these symptoms have been occurring for the past six months and are often exacerbated by stress. The patient denies any significant weight loss or rectal bleeding. On physical examination, there 3 are no abnormal findings. The patient has no significant medical history, but she does mention a family history of gastrointestinal issues. PLANNING MANAGEMENT Which of the following is the most appropriate first step in treatment? A. Amitriptyline B. Lactulose C. Macrogol D. Sennakot E. Loperamide  1 2 3 4 5 6 7 8 A 32-year-old female presents to her primary care physician with complaints of recurrent abdominal pain, bloating, flatulence and constipation. She mentions that these symptoms have been occurring for the past six months and are often exacerbated by stress. The patient denies any significant weight loss or rectal bleeding. On physical examination, there 3 are no abnormal findings. The patient has no significant medical history, but she does mention a family history of gastrointestinal issues. PLANNING MANAGEMENT Which of the following is the most appropriate first step in treatment? A. Amitriptyline B. Lactulose C. Macrogol D. Sennakot E. Loperamide Answer: C​ Although answers A-D are correct, amitriptyline would not be a first choice agent due to significant side effects, sennakot is a stimulant laxative and should be used in conjunction with a stool softener, macrogol tends to cause less flatulence and cramping abdominal pain than lactulose, which are problematic symptoms for this lady.​ KEY POINTS IBS is the most common cause for gastroenterology referral It is characterised by chronic abdominal pain with altered bowel habit without an organic cause Its aetiology is unclear It is mainly a clinical diagnosis supported by investigations to rule out other differentials if clinically indicated Treatment is multimodal but mainly depends on dietary and lifestyle changes and symptomatic pharmacological management RESOURCES UpToDate - Pathophysiology of irritable bowel syndrome UpToDate - Clinical manifestations and diagnosis of irritable bowel sy ndrome in adults UpToDate - Treatment of irritable bowel syndrome in adults BMJ best practice- Irritable Bowel Syndrome https://www.ncbi.nlm.nih.gov/books/NBK536930/#:~:text =Mechanism%20of%20Action,-Lactulose%2C%20also% 20known&text=Lactulose%20reduces%20intestinal%20a mmonia%20production,transit%20time%20and%20intral uminal%20pH. https://pubmed.ncbi.nlm.nih.gov/30546252/#:~:text=Macr