IBS Flashcards
what age is onset most common?
20-30 years
What gender is more common?
x2 more common in females
is the structure of the gut affected in IBS?
NO- the structure of the gut is normal!
It is a functional disease
IBS symptoms?
Abdominal pain
diarrhoea or constipation
flatulence
bloating
urgency to defecate
nausea
lethargy
mucus in stools
What is the criteria for an IBS diagnosis?
- Abdominal pain for at least 6 months
It is relieved by defecation
AND at least 2 of the following:
Abdominal bloating, distension
Altered stool passage- straining, urgency, incomplete stool
Worsened by eating
Passing mucus
What criteria is used to diagnose IBS- what are the factors and what are the patient groups?
The Rome IV criteria
Abdominal pain for 1 day per week in last 3 months
symptoms for at least 6 months
+ 2 or more:
Related to defecation
Change in stool form
Change in tool frequency
Then patient is classifies into following (uses Bristol stool chart):
The Rome IV criteria
Abdominal pain for 1 day per week in last 3 months
symptoms for at least 6 months
+ 2 or more:
Related to defecation
Change in stool form
Change in tool frequency
Then patient is classifies into following (uses Bristol stool chart):
- IBS-C - predominant constipation symptoms
25% of stools are types 1/2, <25% are types 6/7 - IBS-D predominant diarrhoea symptoms
>25% of stools are types 6/7, <25% are types 1/2 - IBS-M - mixed symptoms
>25% of stools are types 1/2 and >25% are types 6/7 - IBS-U - unclassified- symptoms point to its but can’t be classified into the 3 groups above.
What are the 4 classifications of IBS from the ROME IV criteria?
Then patient is classifies into following (uses Bristol stool chart):
- IBS-C - predominant constipation symptoms
25% of stools are types 1/2, <25% are types 6/7 - IBS-D predominant diarrhoea symptoms
>25% of stools are types 6/7, <25% are types 1/2 - IBS-M - mixed symptoms
>25% of stools are types 1/2 and >25% are types 6/7 - IBS-U - unclassified- symptoms point to its but can’t be classified into the 3 groups above.
What are the treatment options for IBS?
- Anti-spasmodic drugs- preferred
Directly relax smooth muscle
e.g. alverine citrate 60-120mg up to TDS
Or Mebeverine 135mg TDS - Peppermint oil capsules- 1-2 caps up to TDS
- Hyoscine butylbromide- can be used but have more anti-muscarine effects so avoid if possible
Anti-depressants
unlicenced for ibs
used if patients don’t respond to typical treatments
e.g. 1st :Tricyclic antidepressant e.g. Amitriptyline 10-30mg ON
2nd: SSRI e.g. sertraline, citalopram, fluoxetine
Laxatives- if IBS-C predominant
Can use any laxative class BUT avoid Lactulose- increases gas production and so can worsen symptoms. also, draws water into the bowel = diarrhoea
Loperamide- if IBS-D predominant
only should be used for attacks- up to 48 hours
can use for 2 weeks max, as long as individual bouts are only 48 hours
Linaclotide:
moderate-severe IBS-C that patient has had for at least 12 months
only if max laxative doses have been inadequate
dose= 290 mcd od, 30 mins before food
What laxative should be avoided in treating IBS?
Lactulose- increases gas production and so can worsen symptoms. also, draws water into the bowel = diarrhoea
Red flag symptoms for referral?
- Unintentional weight loss
- unexplaind rectal bleeding
- family history of bowel or ovarian cancer
- anaemic
- elevated inflammatory markers- could be IBD
- abdominal ore rectal masses
What is the MOA of anti-spasmodics?
e.g. anti-spasmodics
Exact moa is unknown but:
- Acts on smooth muscle cells- blocks voltage gated sodium channels = this prevents the build up of intracellular calcium = decreased contractility of smooth muscle
What is the MOA of linaclotide?
Is a guanylate cyclase-c agonist
- GC-C activation= increased production of cGMP
- cGMP stimulates cystic fibrosis transmembrane conducts regulator (CFTR) ion channel
- CFTR ion channel- increases secretion of chloride and bicarbonate into the intestinal lumen, this increases the moisture of the lumen and therefore aids gi transit
