MET3 Revision - Gastroenterology I Flashcards
State 7 red flags for cancer w/ diarrhoea [7]
- Change in bowel habit
- Bleeding
- Weight loss, unintentional
- FH bowel or ovarian cancer
- > 50 and for >6 weeks
- Anaemia (anyone who doesnt have periods and has IDA has colorectal cancer until proven otherwise)
- Abdominal or rectal mass}
What causes secretory diarrhoea? [5]
Excess secretion of water:
- IBD
- Salmonella infection
- Enterotoxins: E. coli, V. cholera
- Bile salts
- Hormones
Give three examples of motility related diarrhoea [3]
- Thyrotoxicosis
- IBS
- DM autonomic neuropathy
How do you distinguish between steatorrhoea from pancreatic insufficiency and small intestine disease? [4]
Pancreatic insufficiency:
- High faecal fat (rare to test now)
- High faecal elastase (more common to test)
- Normal red cell folate
- Pancreatic calcification on US
Small intestinal disease:
- low red cell folate (folate is absorbed higher up GI)
- anti-TTG: CD
- CT
- XR}
What would the following symptoms indicate about the infective cause of diarrhoea?
· Rapid onset of symptoms (within a few hours after eating) [1]
· Fever [1]
· Bloody diarrhoea [1]
· Abx [1]
Rapid onset of symptoms: (within a few hours after eating)
- this may be from a toxin-producing organism (i.e. reheated takeaways/rice from B.cereus, S.aureus from creamy products)
Fever
- is associated with invasive bacteria: such as campylobacter, salmonella, shigella), enteric viruses, and cytotoxic organisms such as C.dificile, E.histolytica.
Bloody diarrhoea
- is caused by invasive bacteria (is termed dysentery, bacillary dysentery).
Abx
- is associated with C.dificile
Which therapeutic drugs are associated with chronic diarrhoea? [8]
- Alcohol
- Antibiotics
- Anti-depressants (lithium, SSRIs)
- Anti-hypertensives
- Statins / Cholesterol-lowering agents
- GI drugs (Mg++, H2RA, PG analogs, 5-ASA)
- NSAIDs
- Oral hypoglycaemics like biguanides
Describe the blood tests for diarrhoea [7]
- FBC: check for anaemia
- WCC platelets, CRP: for signs of infection / inflammation
- U&E: signs of AKI / dehydration
- Albumin, Ca, P – give info on nutritional status
- Haematinics: folate absorbed in proximal small bowel, B12 absorbed in stomach and distal small bowel
- IgA TTG antibodies for coeliac disease
- TFTs: undiagnosed thyrotoxicosis can cause chronic diarrhoea
Describe stool test for diarrhoea investigations [5]
- Stool weight: useful but difficult to do in practice
- Culture stool for infection: MC&S, cysts, ova, parasites, CDT
- Faecal calprotectin: (protein produced by neutrophils so inflammation in bowel increases the amount of calprotectin shed so will show up in a stool specimen): easy test for infection and IBD, commonly used in follow-ups for IBD patients
- Faecal immunochemical test for Hb: highly specific test for blood in the stool - colorectal cancer
- Faecal elastase looks for pancreatic disease
- Stool pH / electrolyte balance / reducing substances (see if patients are taking laxatives)
What is the gold standard for investigating diarrhoea? [1]
Colonoscopy & biopsy
(Also:
- Duodendal biopsy
- Small bowel MRI
- Video capsule endoscopy
- Cross sectional imaging)
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Which viruses commonly cause viral gastroenteritis? [3]
Rotavirus
Norovirus
Adenovirus (tends to cause respiratory symptoms)
E. coli produces which toxin? [1]
Which syndrome can it lead to and why? [2]
Produces Shiga toxin
Leads to haemolytic uraemic syndrome due to destruction of rbc
How do you treat Campylobacter jejuni infection? [3]
- Clathromycin (1st line)
- Azithromycin
- Ciprofloxacin
A patient has recently eaten fried rice left at room temperature. They are reported vomitting and then diarrhoea.
What is the most likely pathogen causing these symptoms? [1]
Bacillus cereus
What syndrome can Shigella cause? [1]
Name two treatments [2]
haemolytic uraemic syndrome:
Treatment of severe cases is with azithromycin or ciprofloxacin.
Which parasite is found in the small intestines of mammals and causes diarrhoea via a faecal-oral transmission? [1]
Giardia lamblia
How do you treat Giardia lamblia? [2]
tinidazole or metronidazole
[] is a severe inflammation of the inner lining of the large intestine, manifests as an antibiotic-associated colonic inflammatory complication.
What is the most common cause of this? [1]
How does this present? [1]
Pseudomembranous colitis, a severe inflammation of the inner lining of the large intestine, manifests as an antibiotic-associated colonic inflammatory complication.
The most common cause of this is clostridium difficile infection, which can present on sigmoidoscopy with yellow plaques on the intraluminal wall of the colon.
Which antibiotics are most likely to cause C. difficile infection? [2]
Second and third-generation cephalosporins are now the leading cause of C. difficile.
Clindamycin is historically associated with causing C. difficile but the aetiology has evolved significantly over the past 10 years.
C. difficile: think C!
First episode of C. difficile infection:
Oral [] is the first line antibiotic for use in patients with C. difficile infection
second-line therapy: oral []
third-line therapy: oral [] +/- IV []
Oral vancomycin is the first line antibiotic for use in patients with C. difficile infection
second-line therapy: oral fidaxomicin
third-line therapy: oral vancomycin +/- IV metronidazole
How do you differentiate between moderate and severe C. diff infection? [1]
A raised WBC count (but less than 15 * 109 per litre) is indicative of a moderate C. difficile infection.
If the WBC count is greater than 15 * 109 per litre, it is indicative of a severe infection.
State 7 red flag symptoms when asking about dyspepsia [7]
- dysphagia
- weight loss (unintentional)
- persistent vomiting
- epigastric mass
- GI bleeding
- iron deficiency
- new/ persistent unexplained symptoms > 55y
A ptx presents with upper GI discomfort but after endoscopy there is no evidence of an ulcer. What is this called? [1]
Non-ulcer dyspepsia
State the 4 most common causes of dyspepsia [4]
- No lesions / non-ulcer dyspepsia (75%)
- Peptic ulcer disease (10-15%)
- Oesphagitis (15%)
- Cancer (2%)
Name 4 factors that increase the likelyhood of GORD [4]
- Obesity (BMI > 30; increases intra-abdominal pressure)
- Smoking, alchohol and coffee
- Drugs (relax LOS): tricyclics, anticholinergics, nitrates, calcium channel blockers
- Fatty foods
- Pregnancy
NB: no association with H. pylori.
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Describe the pathophysiology of GORD [3]
- High intra-abdominal pressure combined with LOS relaxation and / or abnormalities causes gastric acid, bile, pepsin and pancreatin enzymes are able to reflux back into the oesophagus, causing mucosal injuries
- Often combined with decreased oesophageal motility, causing decreased oesophageal clearance
- The gastric acid levels are normal, just in the wrong place
Describe a cause of LOS dysfunction [1]
Hiatus hernia: herniation of the stomach up through the diaphragm. Causes the opening from the oesophagus to the stomach to be wider, and more stomach content can reflux into the oesophagus
Describe the 4 different types of hiatus hernia [4]
Type 1: Sliding
Type 2: Rolling
Type 3: Combination of sliding and rolling
Type 4: Large opening with additional abdominal organs entering the thorax
GORD can lead to macroscopic oesophagitis.
Define macroscopic oesophagitis [1]
Ulcerations of the oesophagus
Why is GORD developing macroscopic oesophagitis clinically signfiicant? [3]
- Causes strictures
- Can cause Barrett’s oesophagus: can lead to cancer
Describe the LA Classification of oesophagitis [4]
Grade A
- At least one mucosal break, up to 5 mm, that does not extend between the tops of two mucosal folds
Grade B:
- At least one mucosal break, more than 5 mm long, that does not extend between the tops of two mucosal folds
Grade C:
- At least one mucosal break that is continuous between the tops of two or more mucosal folds but which involve less than 75% of the circumference
Grade D:
- At least one mucosal break which involves at least 75% of the esophageal circumference
Describe the pathophysiology of Barrett’s oesophagus (BO) [2]
Chronic oesophageal injury from chronic reflux of gatstric contents; causes a change from squamous to columnar epithelium (process is called metaplasia)
What is the name of the surgery for GORD? [1]
Nissen fundoplication.
Explain why you would perfom a skin biopsy for a coeliac patient? [1]
Explain the pathophysiology of this disease [1]
test initially in any patient with skin lesions suggestive of dermatitis herpetiformis:
- caused by granular deposits of IgA at the dermal papillae of lesional and perilesional skin by direct immunofluorescence
