Irritable Bowel Syndrome Flashcards
What is IBS?
A life long relapsing condition of the lower GI tract that is often life irregular
It is caused by spasm like pain that causes irregular bowel habits.
Suspected if symptoms for at least 6 months:
1. Abdominal pain
2. Bloating
3. Change in bowel habit
Which gender is more affected by IBS?
Females 2:1
What is the pathogenesis of IBS?
IBS is a functional disorder with no known structural, anatomic or biochemical lesions
What causes abnormal GI motility?
- Visceral hypersensitivity
- Abnormal immune function
- Change in colonic microbiota
- Abnormal central pain processing of afferent gut signals
- Abnormal autonomic activity
How would you diagnose a patient with IBS?
If the patient reports abdominal pain or discomfort that is either relieved by defecation or associated with altered bowel frequency or altered stool form.
Also:
1. Altered stool passage
2. Passage of mucus
3. Abdominal bloating, hardness, distension or tension
4. Symptoms made worse by eating
What is type 1 stool?
Separate hard lumps
What is type 2 stool?
Sausage shaped but lumpy
What is type 3 stool?
Like a sausage but with cracks on its surface
What is type 4 stool?
Like a sausage or snake, smooth and soft
What is type 5 stool?
Soft blobs with clear cut edges
What is type 6 stool?
Fluffy pieces with ragged edges - a mushy stool
What is type 7 stool?
Watery - no solid pieces
Entirely liquid
What questions would you ask in a clinical assessment?
- Type and severity of symptoms
- Impact of symptoms on daily functioning
- Diet, nutrition and known food triggers
- Exercise and physical activity levels
- Any recent stresses, anxiety, depression
- Rectal bleeding
What would you examine in a patient for IBS?
- Check weight - calculate BMI, assess for unintended or unexplained weight loss
- Palpate the abdomen for signs of tenderness or masses
- Rectal examination to exclude perinatal or rectal pathology
What diagnostic tests would you do for IBS?
IBS is a diagnosis of exclusion - there is no specific diagnosis
If IBS criteria met check: to exclude other diagnosis
1. FBC
2. ESR
3. CRP
4. Antibody testing for coeliac disease
What are the non GI symptoms?
- Lethargy
- Nausea
- Backache
- Headache
- Bladder symptoms
What are the lower GI alarm symptoms?
- > 40 with unexplained weight loss and abdominal pain
- > 50 unexplained rectal bleeding
- > 60 with occult blood in the faeces, IDA and changes in bowel habit
- <50 with rectal bleeding, unexplained weight loss, IDA, abdominal pain and change in bowel habit
What are the differential diagnoses that could be made?
- Ulcerative colitis
- Crohns
- Gallstones
- Peptic ulcer
- Coeliac
- Chronic pancreatitis
- Hypo/hyperthyroidism
- GORD
- Laxative misuse
- Antibiotic associated diarrhoea
- Malignancy
What general dietary advice could you give to a patient?
- Take regular meals
- Avoid missing meals/long gaps
- Drink >8 cups of fluid per day
- Restrict tea/coffee to 3 cups per day
- Limit fresh fruit to 3 portions per day
- Reduce alcohol and fizzy drinks
- Reduce intake of resistant starch - rice, beans and potatoes
- Avoid sorbitol if diarrhoea
- Eating oats may help wind and bloating
What advice would you give regarding fibre?
Diarrhoea - reduce insoluble fibre (whole grain, wheat and veg)
Constipation - increase in soluble fibre
If advised to increase dietary fibre this should be soluble fibre such as ispaghula husk or foods high in soluble fibre such as oats and nuts
What foods are high in FODMAPs?
- Many green veg
- Most lactose containing foods
- Some fruits (cherries, apples, peaches and nectarines)
- Artificial sweeteners
When are antispasmodics used?
When abdominal pain is the predominate side effect
How do antispasmodics work?
Relax the smooth muscle of the gut and relieve the spasm and distension
What are the antispasmodics and their side affects?
Mebeverine - generally well tolerated and can be used on an as req basis
Hyoscine butylbromide - alleviates colicky pain of GI spasm
Can cause dry mouth, blurred vision or palpitations
C/I in patients with glaucoma
Used with caution in pregnant women, elderly and prostate problems
What is the second line treatment of IBS?
Antidepressants - SSRI’s or TCA’s
How do antidepressants relieve IBS?
Potentiate analgesics and may alter pain perception
Normalise GI transit time
TCA’S…..
Start at low dose (5-10mg equivalent of amitriptyline ON - off label indication)
Dose should rarely exceed 30mg
S/E’s include drowsiness, fatigue, dry mouth and constipation
Try for at least 4 weeks and review every 6-12 months
SSRI’s…..
Low dose if TCA’s not tolerated,C/I or ineffective
Eg. Citalopram 20mg OD
What would you prescribe in IBS-D?
Loperamide and co-phenotrope
Loperamide…..
Preferred as it doesn’t cause confusion or anti-cholinergic S/E’s
Available as a syrup for fine tuning of dose to minimise constipation
Can be used as a regular medication or PRN basis
Aim to produce a comfortable, regular, soft well formed stool
How do bulk forming laxatives work?
Contain soluble fibre and add bulk to stool, retain fluid in stool, stimulate peristalsis and have stool softening properties
Examples of bulk forming laxatives?
Ispaghula husk and methylcellulose:
- Must not be taken immediately before bed
- Ensure adequate fluid intake to prevent intestinal obstruction
- Can take 2-3 days to take effect
Osmotic laxatives…
Can aggravate bloating and abdominal pain
Macrogols act quickly and can use as needed
What is linaclotide?
A once daily guanylate cyclase C receptor agonist that also increases intestinal fluid secretion
NICE recommend if optimal/maximal doses of laxatives from diff classes are ineffective and they have had constipation for at least 12 months
Review after 12 weeks
