Irritable Bowel Syndrome

Question 1

Definition

Answer 1

A chronic, relapsing, and often lifelong disorder
Affects lower GI tract for at least 3 months
No discernable structural or biochemical cause = considered functional

Question 2

Epidemiology

Answer 2

Young adults = 20-30 years
- prevalence decreases with increasing age
Female

Question 3

Risk factors

Answer 3

Family history
GI infection/inflammation
Dietary factors - alcohol, caffeine, spicy, fatty foods
Psychosocial factors: anxiety, depression, PTSD, previous physical or sexual abuse
Drugs: antibiotics

Question 4

Aetiology

Answer 4

No organic cause
Things which can exacerbate are:
- Stress
- Microbial dysbiosis
- Having a high FODMAPS diet (high in short-chain cabs)
- Gastroenteritis
- Menstruation

Question 5

Pathophysiology

Answer 5

A mixture of group abdominal symptoms for which no organic cause can be found = functional bowel disorder:
- Disorder of intestinal motility: short chain carbs can act as solutes that draw in more water into lumen - wall stretchers = pain
- Enhanced visceral perception: hypersensitivity: sensory nerve endings have strong response to stimuli when bowel stretches after a meal = more pain
- Dysfunction of brain gut axis
- Microbial dysbiosis (imbalance)
Pain is often relieved by defecation
3 types:
- IBS - C
- IBS - D
- IBS - M

Question 6

Signs

Answer 6

Following symptoms for at least 6 months: (ABC)
Abdominal pain
Bloating
Change in bowel habit

Question 7

Diagnostic criteria

Answer 7

Abdominal pain/discomfort associated with 2+ of:
- Altered stool passage (straining, urgency, incomplete evacuation)
- relieved by defecation
- altered stool form
- altered bowel frequency, constipation then diarrhoea
- passage of mucus per rectum
- symptoms worse after eating
- abdominal bloating, distension, or hardness

Question 8

Symptoms

Answer 8

Abdominal distention
Mucus in rectum + stool
Worsening of symptoms after food

Question 9

IBS = multisystem disorder…

Answer 9

Painful periods
Bladder symptoms:
- frequency
- urgency
- nocturia
- incomplete emptying
Back pain
Joint hypermobility
Fatigue
Nausea

Question 10

Exacerbations

Answer 10

Stress
Menstruation
Gastroenteritis
Food

Question 11

Diagnosis

Answer 11

Diagnosis of exclusion
- FBC = anaemia = non IBS
- ESR + CRP = inflammation = non IBS
- Anti=tTG/EMA = coeliac disease
- Stool testing = faecal calprotectin = IBD not IBS
- Colonoscopy = IBD, colorectal cancer ruled out
- X - ray = rule out small and large bowel obstruction

Question 12

Treatment

Answer 12

FIRST LINE = Dietary modification
- regular meals
- fluids
- avoid caffeinated, alcoholic, fizzy drinks,
- avoid fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPS)
- avoid stress/anxiety/depression
SECOND LINE = (moderate IBS)
- pain/bloating = antispazmodics = mebevabine, buscopan, ranetidine
- constipation = bulk forming laxatives = fybogel (ispaghula husk), senna
- if severe constipation symptoms persist for atleast 12 months = LINACLOTIDE
- diarrhoea = loperamide
severe = TCA = amitriptyline