IBD Flashcards
what is IBD?
inflammatory disease of the bowel
idiopathic and chronic
follows a course of flares and remission of symptoms
CD - affects any part of the GIT
- patchy transmural inflammation
- deep ulceration - mucosal extension
- granulomas
- has fistulae and strictures
- perianal disease
UC - limited to colon
- mucosal inflammation
- not associated with fistures or strictures
- no granulomas
- no perianal disease
- left sided in most cases
aeitiology of IBD?
unknown, idiopathic but many causes associated:
- diet
- mycobacterium
- stress
- environmental
- dysbiosis in enteric bacteria - use of pre/probiotics helps
- smoking increases risk of CD
- drugs e.g. NSAIDs can precipitate relapse of UC & CD
CD genetic:
- variation of CARD 15 gene on chromosome 16 increases risk by 20%
- more likely if family member has it
- higher prevalence in ashkanazi jews and caucasians
UC genetic:
- variation of HLA gene on chromosome 6
- variation of IL10 gene on chromosome 1
- variation of ARPC on chromosome 2
- higher prevalence in ethnic minorities - south asians
host immune responses:
- both CD and UC have activated innate and acquired immune responses + loss of tolerance to enteric bacteria
- enhances production of pro-inflammatory cytokines and chemokines e.g. IL-12, IL-18, TNF-alpha
symptoms of UC and CD and differences in symptoms
diarrhoea - bloody in UC, no bleeding in CD
fever
abdominal pain > in CD
weight loss > in CD
malnutrition > in CD
rectal bleeding > in UC
dehydration > in UC
iron deficiency anaemia
raised CRP/ESR
hypoalbuminaemia
investigations to confirm
stool tests
- RBCs + WBCs
- C.difficile toxins
- faecal calprotectin - released in intestine in excess when inflammation
bloods:
- Increased CPR
- increased ESR
- increased platelets
- decrease haemoglobin - internal bleeds
- decreased Mg, Zinc - malsbsorption
imaging:
- flexible colonoscopy - doc can examine colon through tube inserted into anus
- sigmoidoscopy - doc can examine left side of colon through tube inserted into anus - diagnostic for UC
- CT scan
- MRI
disease activity scores:
- harvey bradhshaw index (HBI)
- simple clinical colitis activity index (SCCAI)
complications in CD and UC:
CD:
- malabsorption - chronic anaemia
- small bowel obstructions
- perforation
- fistulating disease with abscess
- small and large bowel cancer
- osteoporosis
UC:
- severe bleeding and anaemia
- fluid/electrolyte imbalance
- colorectal cancer
- toxic megacolon
how do we treat IBD?
1) corticosteroids
2) azathioprines, mercaptopurine, methotrexate
3) biologic therapy
4) surgery
use of corticosteroids
used only to induce remission for acute flares of IBD
not used as maintenance - ADRs associated with use > 12 weeks
reduce dose over 8 weeks - or risk of relapse
use of thiopurines
immunosupressant drugs
azathioprine is a pro drug of mercaptopurine
used in active disease or maintenance of remission
used in steroid/dependent and resistant patients
dosing based on weight and thiopurine methyltransferase (TPMT) levels
S.E. of thiopurines and monitoring required before starting
immunosuppression
joint pain
fatigue
liver toxicity
bone marrow suppression - bruising
pancreatitis
monitoring - FBC, liver and renal profile, TPMT genotype, HSV, HIV, HEP B&C, TB exposure
monitoring during treatment - FBC, renal and liver profile, TGN therapeutic range 235-450
TGN - how much thiopurine is in blood
use of methotrexate
immunosuppressant used when thiopurine not effective, tolerated or contraindicated
dose to achieve remission - 25mg OW for 16/52
to maintain remission - 15mg OW for 40/52
- ensure folic acid is prescribed
monitoring before starting:
- HIV, HEP B&C, HSV, TB, EBV exposure
during treatment: FBC, renal and liver profile
S.E of methotrexate
immunosuppression
bone marrow suppression
fatigue
flu-like symptoms
nausea and vomiting
liver toxicity
mouth ulcer
rash
teratogenic
use of biologic
1st line - anti-TNFs
infliximab - 5mg/kg week 0, 2, 4, 6 and 8
can increase to 10mg/kg
adalimumab
- 160 mg week 0
- 80 mg week 2
- 40 mg every 2 weeks
can escalate to 40 mg weekly
monitoring of biologics
contraindications - active infection
pre-screening - FBC, LFTs, CRP, HIV, HEP B&C, active/latent TB
6 monthly monitoring - FBC, LFTs, renal profiles, disease scores, weight, biologic levels
