Week 8 GI and malabsorption Flashcards

1
Q

H. Pylori and damaging lining

A
  • Has urease enzyme, converts urea+water to ammonia + CO2.
  • Ammonia neutralizes the acid environment.
  • Gastric acid production is stimulated which can further damage lining.
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2
Q

characteristics of gastrinoma

A

elevated gastrin
gastrin producing tumours - normally stomach or pancreas.
stimulates excessive stomach acid.

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3
Q

characteristics of acute pancreatitis (exocrine disease)

A
  • elevated levels of serum amylase.
  • Raised inflammatory markers (CRP)
  • Hypocalcaemia: release of lipase, which leads to saponification of calcium.
  • acute abdominal pain
  • associated with alcoholism and gall stones.
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4
Q

characteristics of chronic pancreatitis

A

deficient pancreatic activity.
- low enzyme level, malabsorption
- low levels of faecal elastase- pancreas specific enzyme

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5
Q

4 main absorption

A
  1. carbohydrate absorption
  2. fat absorption
  3. protein absorption
  4. bile acid absorption
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6
Q

carbohydrate absorption

A
  • non-invasive test: testing the absorption of xylose a monosaccharide, and also disaccharides.
  • small bowel biopsy: test to see the enzyme activity.
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7
Q

amino acid malabsorption

A

affect both intestinal and renal-epithelial transport.
hartnup disease: neutral amino acids (transport impaired)
cystinuria (di amino acid transport impaired)

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8
Q

bile salt absorption and function

A

BS is essential in the absorption of lipids and fat-soluble vitamins

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9
Q

bile salt malabsorption

A

bile salt is normally absorbed and stored in the gall bladder.
If malabsorption of BS, it will be passed onto the colon.
The accumulation of BS in the colon will convert it to toxic secondary BS.
toxic 2dary BS will lead stimulate the secretion of water and electrolytes.
secretory diarrhea.

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10
Q

hartnup disease

A

neutral amino acid

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11
Q

13C triglyceride breath test is for?

A

normal fat absorption will have high CO2 release.
fat malabsorption will have low CO2 release.

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12
Q

75Se-HCAT test

A

A low retention can indicate BS malabsorption.

  • 75Se labelled bile acid given orally.
  • If 75Se retention is low, BS malabsorption.
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13
Q

Serum cholestenone significance

A

Increases in bile acid malabsorption:
- cholestenone is an intermediate in BS synthesis pathway.
- cholestonone is increased in increased bile acid turnover due to excessive loss.

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14
Q

Coeliac disease

A

autoimmune disorder: triggered by gluten
antibodies against transglutaminase (tTGA).
LEADS TO small intestine cell damage.
villous atrophy and malabsorption

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15
Q

what is tissue transglutaminase’s abbreviation

A

tTGA

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16
Q

what are the 2 antibodies against tTGA?

A

IgA: high sensitivity and specificity
IgA deficiency:
test IgG

17
Q

gold standard to diagnose coeliac disease

A

small bowel biopsy

18
Q

Inflammatory Bowel Disease (IBD) is…

A

Group of chronic inflammatory diseases of large and small intestines.

19
Q

2 main diseases of IBD are

A

Ulcerative Collitis
Crohn’s Disease

20
Q

Inflammatory Bowel Disease symptoms

A
  • Bloody stool
  • Diarrhoea
  • Frequent bowel movements
  • weight loss
21
Q

feature of ulcerative collitis

A

occur in large intestine and colon

22
Q

feature of Crohn’s disease

A

patchy areas of inflammation

23
Q

What is calprotectin used for?

A

Biomarker
inflammatory bowel disease will lead to release of calprotectin from neutrophils:
distinguishes IBD from non-inflammatory bowel disorders
(irritable bowel syndrome - IBS)

24
Q

negative result of calprotectin

A

not likely to be IBD, reduce the need of endoscopy

25
elevated faecal osmotic gap appears in ... diarrhoea
**osmotic diarrhea**:draws water into GI that leads to diarrhea. - malabsored nutrients - osmotic laxatives:
26
what is a VIPoma
- a **pancreatic tumour** that secretes excessive VIP - 60-80% are malignant
27
effect of VIP (vasoactive intestinal polypeptide)
- secretion of water in **bile and pancreatic juice**. - secretion of water and electrolytes in **GI**. - **inhibit** intestinal absorption
28
which organ is VIPoma associated with
pancreas
29
where are carcinoid tumours located?
all GI tracts
30
what do carcinoid tumours secrete
serotonin
31
biomarker of carcinoid tumour/syndrome
metabolite of serotonin: 5-HIAA
32
Pathway of serotonin metabolism
tryptophan -- serotonin -- 5-HIAA
33
carcinoid tumour (biomarker changes): tryptophan, serotonin, 5-HIAA
1. excessive **tryptophan** is used as a substrate 2. there will be excessive **serotonin** and **5-HIAA**, the metabolite of serotonin.
34
what is significant in diagnosis of malignancy (example with VIP)
stability of gut hormone, VIP is highly unstable
35
carcinoid tumour - symptoms
- **diarrhea** - **skin flushing**, this is due to the secretion of vasoactive hormones and sertonin from the tumour
36
severe diarrhea will lead to ... (biochemistry)
low potassium and chloride
37
secretory vs osmotic diarrhea
faecal osmotic gap: - **secretory diarrhea** has electrolyte and water secreted into GI, thus **normal osmotic gap**. - **Osmotic diarrhea** only has water drawn into the GI tract, thus **higher osmotic gap** in the faeces.
38
faecal osmotic gap
290 - faecal electrolyte (Sodium and Potassium) levels