Diarrhoea 2 Flashcards
What signs do you look for on examination with diarrhoea?
- Clubbing
- Iritis? Episcleritis? Scleritis
- Mouth ulcers
- Eryhema nodusm
- Dermatitis herpetiformis
- Virchow’s lympahdenopathy
- Abdominal Msas
- Anal ulcers or fistulae
- DRE
What would clubbing and diarrhoea suggest?
- Crohn’s disease
- UC
- hyperthryoidism
- coeliac disease (unlikely)
What would Iritis (anterior uveitis), Episcleritis, Scleritis with diarrhoea suggest?
UC and Crohn’s
What would mouth ulcers and diarrhoea suggest?
Crohn’s produces ulcers anywhere GI tract mouth to anus
What would erythema nodusum and diarrhoea suggest?
- Crohn’s and UC
2. COCP can also cause this in young women
What would dermatitis herpetiformis and diarrhoea suggest?
scalp and on extensor surfaces of limbs very itchy signs of coeliac disease
What would Virchow’s lymphaednopathy suggest with diarrhoea?
bowel malignancy that has spread
What would mass in RLQ with diarrhoea suggest?
Crohn’s (due to inflammation of terminal ileum)
What would mass elsewhere esp LLQ with diarrhoea suggest?
malignancy
What would anal ulcers and fistulae with diarrhoea suggest?
Crohn’s (patient may be unaware of these so inspect)
Why do you peform a DRE with diarrhoea?
- causes of obstruction for overflow diarrhoea esp malignant recta carcinoma
- check if feaces is mucoid or bloody
What blood tests should you do for diarrhoea?
- FBC
- ESR
- CRP
- TTG and IgA levels
- TFTs
- U+Es
- Albumin
- Capillary glucose
What would anaemia on FBC with diarrhoea suggest?
- coeliac disease
- UC
- Crohn’s
When is ESR elevated?
UC and Crohn’s
When is CRP elevated?
UC, Crohn’s, infectious diarrhoea
Why do you carry out a TTG?
positive result has sensitivity and specificity of over 90% for coeliac disease
Why do you measure IgA?
- IgA can cause false negative for TTG if deficient
2. Antigliadin antibodies can also be used instead of TTG but they are less specific and sensitive
What TFTs would suggest hyperthyroidism?
ow TSH but high T3/T4
Why do you measure U+Es?
may be suffering electrolyte loss and be dehydrated
When is albumin low?
patients with chronic diarrhoea and malabsoprtion e.g. IBD
Why do you measure capillary glucose?
easy, quick and checks if patient diabetic
What feaces tests do you carry out for diarrhoea?
- Feaces microscopy and culture
- C.diff toxin test
- FOBT
Why do you carry out feaces microscopy and culture?
- exclude infection (can be false neg in Giardia)
2. pus cells visible can indicated inflammation in IBD
When do you carry out a c.diff toxin test?
if recent antibiotic use
What does it mean if FOBT comes back positive?
- Infection or UC
2. Less likely to be hyperthyroidsm, coeliac disease and IBS
When can you request a FOBT?
after stopping drugs that cause bleeding (e.g. aspirin and warfarin as can give false positive)
What is key difference between Crohn’s and UC?
- UC: bloody diarrhoea and pain diffuse
- Crohn’s: abdominal pain starts in RLQ and no bloody diarrhoea - more likely to have weight loss and failure to thrive between attacks
What are second line investigations to confirm or exclude Crohn’s disease?
- ABX
- Colonscopy
- Double contrast barium enema
What could a ABX show?
- bowel inflammation
- check if UC toxic megacolon
What can a colonoscopy visualise in crohn’s?
discrete interuppted lesions of Crohn’s disease (or diffuse, erythematous inflammation of UC)
What action does colonscopy allow you to take?
biopsies to be taken in search of non-caesating granulomas in bowel mucosa (hallmark of Crohn’s)
When do you do a DCBE?
when colonoscopy not possible
What could a DCBE show in crohn’s?
discrete lesions and strictures in colon suggestive of crohn’s
What are the symptoms of Crohn’s due to?
chronic activation of immune system in various tissues (e.g. bowel wall)
What is the sequelae of Crohn’s?
- abcesses
- fistulae
- strictures
- adhesions
- perforation
What type of medicine is used to treat Crohn’s?
immunosuppressants
What steroid-sparing immunosuppressants are used to treat Crohn’s LT?
- methotrexate (folate antagonist)
- azathioprine (purine synthesis inhibitors
- Anti-TNF alpha monoclonal antibodies (infliximab)
Why are steroid-sparing immunosuppressants used?
- avoid steroid complications (diabetes, osteoperosis, cataracts)
- steroids don’t modify disease or induce sustained mucosal healing
Do patients with Crohn’s need surgery?
- ultimately need to surgery to resect most affected portion of bowel
- BUTit is temporary
- so medical management better and more important
What is the cause of Crohn’s?
mutations in genes responsible for cleaning up phagocytosed bacteria
What happens to this bacteria in Crohn’s?
- inability of macrophages to correctly clear bacteria they ingest leads to them secreting cytokines
- that make the immune system try to wall off the aberrant situation forming a granuloma
What does a granuloma lead to?
chronic inflammation
What does are the local effects of this?
- diarrhoea
- ulcers
- strictures of bowel
- fistulae between bowel and other compartments
What are the systemic complications of Crohn’s?
- inflammation of eyes (iritis, episcleritis, scleritis)
- the joins (arthritis)
- skin (erythema nodosum)
- anaemia (either from malabsorption or chronic inflammation)
- weight loss
- fatigue
