Irritable bowel syndrome (GI) Flashcards
Define IBS.
Chronic condition characterised by abdominal pain associated with bowel dysfunction (e.g. change in stool frequency or form)
What is the pain in IBS often relieved by?
Defecation
What can IBS pain often be accompanied with?
Abdominal bloating
What demographic does IBS affect most?
- F>M (2:1)
- highest prevalence in people aged 20-39
What could be some contributory factors to IBS? (6)
- inflammatory/immune system involvement (histology can show subtle alterations to gut-homing T lymphocytes + increased mast cells)
- intestinal mucosa
- bacterial overgrowth, bile acid malabsorption
- gut hypersensitivity with enhanced perception of visceral type pain & dysregulation of brain-gut axis
- triggers can be environmental (e.g. stress and emotional tension) or luminal (e.g. certain foods, bacterial overgrowth or toxins, gut distension)
- precipitating dietary associations include caffeine, lactose-containing foods or fructose-containing foods
What are the clinical features of IBS? (7)
- abdominal pain (cramping pain in lower/mid-abdomen >6months, relieved by defecation)
- alteration of bowel habits associated with pain - diarrhoea, constipation or both
- abdominal bloating or distension (relieved with defecation)
- passage of mucus with stool
- urgency of defecation
- symptoms made worse by eating
- no nocturnal symptoms
What is abdominal examination like in IBS?
Normal - could have tenderness in RLQ/LLQ but no other abnormalities
What are the ABC of IBS?
- A - abdominal pain
- B - bloating
- C - change in bowel habit for >=6 months
What are some red flag symptoms for IBS? (4)
- weight loss
- anaemia
- PR bleeding
- late onset (>60)
What are some risk factors of IBS? (7)
- physical and sexual abuse
- PTSD
- age <50
- female sex
- previous enteric infection
- family history
- stress
What is the 1st-line investigation for IBS?
FBC - should be normal
If anaemia or raised WBC = not IBS
What bloods (other than FBC) can we consider for IBS? (2)
- CRP & ESR - rule out infection or inflammation (IBD)
- serologic tests: anti-TTG antibodies (exclude coeliac)
What imaging can we consider for IBS? (2)
- ultrasound - exclude gallstone disease
- flexible sigmoidoscopy/colonoscopy - rule out IBD
What special tests can be considered for IBS?
- faecal calprotectin - to exclude IBD (looks for inflammation - if low, IBD unlikely)
- faecal occult blood - normal in IBS, positive in IBD or colorectal cancer
- quantitative faecal immunochemical test (FIT): >=10mg of Hb/g indicates possible colorectal cancer
- stool sample - exclude dyspepsia associated with H. pylori
What is faecal calprotectin used for?
To distinguish between IBS and IBD - if raised it indicates inflammation in bowel –> IBD
What is the main differential for IBS and what are the different features may this have?
IBD (Crohn’s & UC)
- systemic symptoms - fever, fatigue
- blood in faeces
- raised faecal calprotectin
- raised serum CRP&ESR
What are some differentials for IBS?
- Crohn’s disease - fatigue, diarrhoea, abdo pain, fever, rectal bleeding, oral ulcers, perianal skin tags, fistulae, abscesses, palpable mass in ileocaecal area, no mass present on DRE, faecal occult blood +ve
- ulcerative colitis - bloody diarrhoea, Hx lower abdo pain, faecal urgency, erythema nodosum, acute arthropathy, Hx primary sclerosing cholangitis
- lymphocytic and collagenous colitis
- Coeliac disease - weight loss, early osteoporosis, iron deficiency anaemia, hypocalcaemia, elevated PT, anti-TTG antibodies
- colon cancer
- bowel infection (acute, Giardiasis = diarrhoea, nausea, bloating, steatorrhoea, stool exam)
- non-Coeliac gluten sensitivity (negative anti-TTG)
- bile acid malabsorption (bile acid binder can be used)
- small bowel bacterial overgrowth (bloating, diarrhoea, cramps, altered motility, hydrogen breath testing)
What kind of diagnosis is IBS?
Diagnosis of exclusion
What diagnostic criteria can help diagnose IBS?
Rome IV criteria:
Recurrent abdominal pain, on average at least 1 day per week in the last 3 months and associated with 2+ of the following:
- related to defecation
- associated with a change in frequency of stool
- associated with a change in form (appearance) of stool
What are the different Rome IV subtypes of IBS? (4)
- IBS with constipation (IBS-C): hard/lumpy>25%, loose/watery<25%
- IBS with diarrhoea (IBS-D): loose/watery>25%, hard/lumpy<25%
- mixed IBS (IBS-M): hard/lumpy<25%, loose/watery<25%
- unspecified IBS: insufficient abnormality of stool consistency to meet other criteria
What lifestyle changes are there for IBS?
- fibre (soluble fibre found in ispaghula, oat bran, barley, beans)
- probiotics - actimel, yogurts, supplements
- eliminate precipitating substances e.g. caffeine, lactose or fructose
- stress management
- education
- reassurance
What type of diet can IBS patients try?
Low FODMAP diet - Low Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols
What do we give if constipation-predominant IBS?
- laxative (polyethene glycol PEG)
- 2nd line: secretagogue (serotonin receptor partial agonist) e.g. lubiprostone, linaclotide, plecanatide, tenapanor
What do we give if diarrhoea-predominant IBS?
Antidiarrhoeal (loperamide is 1st line)
