Gastroenterology Flashcards
What does the term “extensive colitis” refer to in Ulcerative colitis?
Disease extending proximal to splenic flexure
What part of the GIT do Crohn’s Disease and UC affect respectively?
Crohn’s -> anywhere from mouth to anus. Transmural inflammation with skip lesions
UC -> involves colon, and rectum is almost always involved. Inflammation limited to mucosa
What biomarker is associated with UC?
pANCA
What biomarker is associated with Crohn’s Disease?
ASCA - anti Saccharomyces cerevisiae Ab
What is the peak age of onset of IBD?
20 - 30 years
What relationship does smoking have with Crohn’s and UC?
Crohn’s -> risk factor
UC -> decreases risk
What gene has been identified in ~40% of Crohn’s and is associated with more severe disease?
NOD2
What percentage of UC patients will end up proceeding to colectomy during the course of their disease?
20%
What percentage of Crohn’s patients end up requiring surgical resection?
50%
Which form of IBD is more associated with colorectal cancer?
UC
What is the colorectal cancer screening program for IBD patients?
Commence after 8 years of disease in UC or Crohn’s which involved >1/3 of colon
- annually for active disease / FHx at age <50 / PSC / stricture / previous dysplasia
- 3 yearly otherwise
- 5 yearly if last two scopes normal
What is the main predictor at diagnosis of severe disease in Crohn’s ?
Name 3 other important predictors
Perianal disease
Requiring steroids at diagnosis
LOW >5kg
Fibro-stenosing disease
What are two laboratory markers used for monitoring disease activity in IBD?
CRP (aim <3)
Faecal calprotectin (aim <150)
What is the treatment goal for patients with IBD?
To achieve remission with complete mucosal healing
What is the first line treatment for mild-moderate UC left-sided/extensive colitis?
Oral + topical 5-ASA agent
What is the indication for immunomodulator therapy in UC?
Non-response to initial therapy with oral 5-ASA + steroid, or requiring more than one course of steroids in the year
What is the steroid regime typically used for induction in mild-moderate IBD?
Prednisolone 40mg for 1-2 weeks, slowly tapered over 6-8 weeks
What is the role of TPMT in thiopurine metabolism?
What happens in high TMPT activity?
What happens in low activity?
TMPT catalyses methylation of 6-MP to the inactive 6-MMP. Xanthine oxidase then catalyses 6-MP to the inactive 6-thiouracil
15% of all patients have high TPMT activity (shunters) → high 6-MMP → hepatotoxicity. Can use allopurinol in this setting.
Heterozygous mutation (11%) → low activity Homozygous mutation (0.3%) → negligible activity → very high 6-TG → BM suppression
Which malignancies occur at increased rates with thiopurine use?
Lymphoma
Non-melanoma skin cancer
What is the first line treatment for rectal UC?
Topical + PO 5-ASA
What is the first line treatment for UC limited to proctitis?
Topical + PO 5-ASA (more effective than topical alone)
In Australia, what is the typical 1st line approach for induction in moderate to severe Crohn’s ?
Steroids + immunomodulator
Steroids - if severe then parenteral with hydrocort or methylpred
Immunomodulator - thiopurine or methotrexate
Which patient group in Crohn’s is budesonide preferred for, over prednisolone?
Mild ileocaecal disease
What is the route of escalation for a patient with Crohn’s who has failure of induction with first line therapy?
When is this change made?
Add on a biologic agent =
- TNF inhibitor (infliximab IV / adalimumab SC
- Alpha4beta7 integrin inhibitor (vedolizumab IV)
After 3 months of 1st line therapy
What is the treatment approach in perianal/fistulising Crohn’s disease?
Surgical consultation for possible drainage / Seton
Antibiotics (ciprofloxacin OR metronidazole)
Combination of anti-TNF (infliximab has strongest evidence) and Azathioprine
What is the medical management approach following surgical resection for Crohn’s?
What medication should all patients generally receive?
All patients should receive 3 months of metronidazole.
For patients with risk factors, add thiopurine and/or a TNF inhibitor (infliximab or adalimumab)
What are the options for 1st line management for stricturing Crohn’s that is uncomplicated and <5cm?
May trial IV steroids and bowel rest if appears to be inflammatory component (based on clinical features/bloods/MRI)
If not - trial endoscopic dilatation
What are the management options for strictures in Crohn’s that are long or complicated in nature?
Strictureplasty or small bowel resection
What is the next line treatment in UC after failure of induction with oral 5-ASA and steroid?
Add an immunomodulator = thiopurine.
Methotrexate if intolerant to thiopurines
How is acute severe UC defined?
Truelove + Witts criteria =
The presence of 6 or more bloody stools per day, plus at least one of the following:
- temperature more than 37.8ºC
- HR >90
- Hb less than 105
- ESR > 30
What is the initial therapy for acute severe UC?
- IV hydrocort / methylpred
- IVF
- clexane
- exclude CMV infection by sigmoidoscopy
When should salvage therapy be considered for acute severe UC?
What are the options?
After 3-5 days of steroid therapy
Medical options:
- infliximab
- cyclosporin
Surgery is alternative
When would a biologic agent be added in UC therapy?
What are the options?
If failed 3 months of 5-ASA + immunomodulator
Options =
- Infliximab
- Vedolizumab
What are the pacemaker cells of the GIT which control peristalsis?
Interstitial cells of Cajal
What is the main acid-producing cell in the stomach?
Parietal cells
What are the main SEs of PPIs? (5)
Enteric infections (C.diff) Pneumonia Hypomagnesaemia Osteoporosis Interstitial nephritis
What is the most common cause of hypergastrinaemia?
Prolonged acid suppression (PPI / H2RA)
How is Zollinger-Ellison Syndrome diagnosed?
Secretin Provocation Test -> measure gastrin levels following provocation
What genetic cancer syndrome is Zollinger-Ellison Syndrome associated with?
MEN1
- Parathyroid
- Pituitary
- Pancreas
What is the gene involved in hereditary pancreatitis?
Trypsinogen gene PRSS1, on chromosome 7q35
What is the management of a symptomatic pancreatic pseudocyst?
Drainage (endoscopic or surgical)
What is ABCB4 disease associated with?
Biliary tract diseases
- intrahepatic cholestasis of pregnancy
- recurrent pancreatitis
What is the most common cause of Peptic ulcer disease in Australia?
H.Pylori (NSAIDs close 2nd)
What location of ulcers is H.Pylori more associated with?
Duodenal
What is the recommended 1st line therapy for H.pylori eradication?
esomeprazole 20 mg orally, twice daily for 7 days
PLUS
amoxicillin 1 g orally, twice daily for 7 days
PLUS
clarithromycin 500 mg orally, twice daily for 7 days
What is the gold standard for diagnosis of H.Pylori if not undertaking endoscopy?
C13- or C14-urea breath test.
What are most cases of Gastric mucosa–associated lymphoid tissue (MALT) lymphoma caused by?
Uncommon disease.
Most cases are caused by H. pylori infection.
What is the first-line treatment of choice for eosinophilic oesophagitis?
6-food elimination diet (wheat, egg, dairy, soy, nuts, seafood)
What are the most common triggers in eosinophilic oesophagitis?
Dairy and wheat are the most common triggers
What is first line medical therapy for eosinophilic oesophagitis (after diet)?
Standard dose PPI therapy
What element on dysphagia history indicates an oesophageal motility disorder rather than mechanical obstruction?
If there is dysphagia with both solids and liquids
Where does Zenker’s diverticulum arise from?
Sac-like outpouching of mucosa and submucosa through Killian’s triangle (area of muscular weakness in the hypopharynx b/w the transverse fibres of the cricopharyngeus and the oblique fibres of the lower inferior constrictor)
What is the classic presentation of Zenker’s diverticulum?
Foul breath, gurgling in the throat, regurgitation of food into the mouth
How is Zenker’s diverticulum diagnosed?
Barium swallow