1. Irritable Bowel Syndrome (IBS)
Gareth Paul Rogers
Irritable Bowel Syndrome (IBS)

2. Learning objectives Epidemiology
Aetiology
Pathogenesis
Signs and symptoms
Investigations
Diagnosis
Treatment
Prognosis
- the incidence and distribution of disease
- the causation or causative factors of disease
- the manner of development of disease

3. IBS is a common functional gut disorder with an unknown cause
IBS is a common functional gut disorder with an unknown cause. Symptoms vary and include abdominal pain, bloating, and bouts of diarrhoea and/or constipation. Symptoms tend to come and go. There is no cure for IBS, but symptoms can often be eased with treatment.
Definition

4. Epidemiology
Prevalence - up to 1 in 5 people in the UK will develop IBS.
Population:
Can affect patients of any age group.
Most common to develop in young adults (20-30 yrs old).
Marginally more common in women than in men (2:1).
Most common in developed nations.

5. Aetiology and pathogenesis
Currently the cause of IBS is unknown.
Working theories:
Over activity of the enteric nervous system.
Food group intolerances.
Abnormal colonization of gut flora- diarrhoea precedes onset of development in 30% of patients.
Oversensitivity to pain.
It is not known why this may occur. It may have something to do with overactivity of messages sent from the brain to the gut. Stress or emotional upset may play a role. About half of people with IBS can relate the start of symptoms to a stressful event in their life. Symptoms tend to become worse during times of stress or anxiety
However, this is thought to be only in a small number of cases.
IBS is not caused by an ongoing gut infection. However, in about some cases, the onset of symptoms seems to follow a bout of a gut infection with diarrhoea and being sick (vomiting), called gastroenteritis. So, perhaps a virus or other germ may sensitise or trigger the gut in some way to cause persisting symptoms of IBS.
People with IBS feel more pain when their gut is expanded (dilated) than those without IBS. They may have a lower threshold for experiencing pain from the guts

7. Investigations No specific investigation
Often investigations are used to exclude differential diagnosis- a diagnosis of exclusion. UC CD
CRC
Coeliac disease
Insufflation during rigid sigmoidoscopy- can induce symptoms but is not routinely performed.

8. Diagnosis ROME III Criteria

9. Treatment There is no cure for IBS.
Explanation, education and reassurance are key.
Avoid known triggers- food groups, stress etc.
Constipation:
Avoidance of insoluble fibre (bran).
Bisacodyl and sodium picosulfate.
Diarrhoea- bulking agent (miraLAX) + loperamide.
Colic/bloating- oral antispasmotics-OTC medication- avoid prescribing

10. Prognosis In 50% of patients symptoms resolve or improve after 1yr.
<5% of patients will experiencing a worsening on their symptoms.

11. Case Scenario: Common IBS Presentation
A 20-year-old woman
Presents with a long-term history of abdominal pain
Pain throughout course of almost entire life
Pain = relieved by defecation + relaxation ,
Worse during final exams
 Fecal leukocytes , RBC’S ,stool culture reveal NO abnormalities  
Colonoscopy revealed no underlying pathology
Notice she is generally an anxious individual
WATCH OUT FOR RED HERRINGS--- What if the patient came in with BLOOD on DEFECATION? WOULD YOU automatically assume it’s IBS just because of the stress component?

12. MCQ 1
According to ROME III criteria, for what length of time must symptom onset be for a diagnosis of IBS?
9 months
4 months
12 months
6 months
3 months
Symptoms must have been present for at least 3/7 for the past 3/12 with onset being >6/12

13. MCQ 2
Which of the following symptoms is not associated with IBS?
Urgency
Mucous on stool
Meleana
Backache
Low mood
Meleana- black tarry stools associated with digestion of blood- upper GI bleed.
1st and 2nd part of the duodenum – duodenal suspensory ligament- marks the boundary between forgut and midgut.

14. MCQ 3 Improvement with defecation
Which of the following is clinically diagnostic of IBS?
Improvement with defecation
Non flushable/pale stools
Blood mixed with stool
LIF pain
Rebound tenderness
Improvement with
defecation