Epidemiology
- Incidence: 2000.00 cases per 100,000 person-years
- Peak incidence: 30-40 years
- Sex ratio: more common in males 2:1
| Condition | Relative incidence |
|---|---|
| Irritable bowel syndrome | 1 |
| Coeliac disease | 0.05 |
| Microscopic colitis | 0.01 |
| <1 | 1-5 | 6+ | 16+ | 30+ | 40+ | 50+ | 60+ | 70+ | 80+ |
Clinical features
The diagnosis of IBS should be considered if the patient has had the following for at least 6 months:
A positive diagnosis of IBS should be made if the patient has abdominal pain relieved by defecation or associated with altered bowel frequency stool form, in addition to 2 of the following 4 symptoms:
Features such as lethargy, nausea, backache and bladder symptoms may also support the diagnosis
Red flag features should be enquired about:
- abdominal pain, and/or
- bloating, and/or
- change in bowel habit
A positive diagnosis of IBS should be made if the patient has abdominal pain relieved by defecation or associated with altered bowel frequency stool form, in addition to 2 of the following 4 symptoms:
- altered stool passage (straining, urgency, incomplete evacuation)
- abdominal bloating (more common in women than men), distension, tension or hardness
- symptoms made worse by eating
- passage of mucus
Features such as lethargy, nausea, backache and bladder symptoms may also support the diagnosis
Red flag features should be enquired about:
- rectal bleeding
- unexplained/unintentional weight loss
- family history of bowel or ovarian cancer
- onset after 60 years of age
Investigations
Suggested primary care investigations are:
- full blood count
- ESR/CRP
- coeliac disease screen (tissue transglutaminase antibodies)
Management
The management of irritable bowel syndrome (IBS) is often difficult and varies considerably between patients. NICE updated it's guidelines in 2015.
First-line pharmacological treatment - according to predominant symptom
For patients with constipation who are not responding to conventional laxatives linaclotide may be considered, if:
Second-line pharmacological treatment
Other management options
General dietary advice
First-line pharmacological treatment - according to predominant symptom
- pain: antispasmodic agents
- constipation: laxatives but avoid lactulose
- diarrhoea: loperamide is first-line
For patients with constipation who are not responding to conventional laxatives linaclotide may be considered, if:
- optimal or maximum tolerated doses of previous laxatives from different classes have not helped and
- they have had constipation for at least 12 months
Second-line pharmacological treatment
- low-dose tricyclic antidepressants (e.g. amitriptyline 5-10 mg) are used in preference to selective serotonin reuptake inhibitors
Other management options
- psychological interventions - if symptoms do not respond to pharmacological treatments after 12 months and who develop a continuing symptom profile (refractory IBS), consider referring for cognitive behavioural therapy, hypnotherapy or psychological therapy
- complementary and alternative medicines: 'do not encourage use of acupuncture or reflexology for the treatment of IBS'
General dietary advice
- have regular meals and take time to eat
- avoid missing meals or leaving long gaps between eating
- drink at least 8 cups of fluid per day, especially water or other non-caffeinated drinks such as herbal teas
- restrict tea and coffee to 3 cups per day
- reduce intake of alcohol and fizzy drinks
- consider limiting intake of high-fibre food (for example, wholemeal or high-fibre flour and breads, cereals high in bran, and whole grains such as brown rice)
- reduce intake of 'resistant starch' often found in processed foods
- limit fresh fruit to 3 portions per day
- for diarrhoea, avoid sorbitol
- for wind and bloating consider increasing intake of oats (for example, oat-based breakfast cereal or porridge) and linseeds (up to one tablespoon per day).