PBL1 Flashcards
ferrograd
– this is an iron supplement that is used to prevent and treat iron deficiency anaemia and vitamin C deficiency when the two are present together, a brand name for ferrous sulphate 200mg
mean corpuscular volume
this is the average volume of red blood cells, average is 80-100
alkaline phosphatase
this is an enzyme found in several tissues throughout the body, it is highest in the cells that are made out of the bone and liver. This is best produced under alkaline pH environmetns and dephosphorylates compounds as it is a phosphate. It is widespread in the liver and skeleton therefore its concentration in the bloodstream can be used as a biomarker, dependent on factors such as age gender and blood type as well as whether the individual is pregnant or not
folate
this is B12, a type of vitamin that is needed, when it is deficiency it can cause the body to produce abnormally large red blood cells that do not function properly
ferritin
this is a protein that is produced by mammalian metabolism which is used to store iron in tissue
IgA anti-tTG
anti tissue transglutaminase, Anti tTg is a newer and more sensitive test and is produced in people with coeliac disease, tTG is what normal people have
antibodies
polypeptides that are produced by plasma cells that combat disease
Formalin
this is used to supress oxidation and polymerisation, it is used to preserve biological species
what makes up gluten
gliadin and glutenin
what is gluten present in
wheat oat, barely and rye
what genes cause coeliac disease
- Usually more likely to have the condition if you have HLA-DQ2 (95%)or HLA-DQ8(5%), having these genes does not necessarily mean that you will develop the disease
describe coeliacs disease
- Caused by an intolerance of gluten
- Exposure to gluten can lead to damage of the proximal small bowel and in serious cases it can affect the whole bowel
- Causes malabsorption leading to conditions such as anaemia
- 1 in 100 people have the condition
what part of the bowel is affected
proximal small bowel
- in serious cases it can affect the whole bowel
what are the symptoms of coeliacs disease
- Diarrhoea
- Abdominal pain
- Bloating and flatulence
- Aches and pains in legs – osteomalacia (softening of the bones) this is due to calcium malabsorption
- Indigestion
- Constipation
- Fatigue - due to iron and folate malabsorption
- Unexpected weight loss – due to malabsorption of fuels such as carbohydrates and fats
- Itchy rash
- Problems getting pregnant
- Irritability – due to folate deficiency
what are the causes of coeliacs disease
- Autoimmune condition
- Where the immune system attacks the villus and the healthy tissue this means that they cannot do there role in the small intestine leading to inflammation
- Damages surface of the small bowel
- Body cannot absorb nutrients
- Change in the composition of gut flora, for example due to infection, stress and hormones that can trigger the activation of genes for coeliac disease
what is the treatment of coeliacs disease
- Gluten free diet
- Iron and folic given in 1st three months after diagnose
- Reassess 8-12 weeks for improvement in symptoms and growth parameter
how does the immune response relate to the gut metabolism
There is an initial immune reaction to the gluten
- Proximal gut is more effected as this is where there is the highest concentration of gluten
- Eventually this reaction develops into an autoimmune reaction against the small intestinal mucosa
- Gluten is the molecules that is broken down into small molecules that are toxic, the main toxic peptide is alpha gliadin
There is an inappropriate T cell mediated response(Th2) against gliadin in genetically susceptible individuals, the initial response may be mediated by a viral infection-adenovirus 12
- There are 2 antibdoeis produced as a result of the immune response
- These are anti-gliadin and anti-endomysial – these can be used to test for the presence of the disease
- The enodmysial antibody attacks the tTG tissue
- The mucosa of the small bowel is more effected
- As you move towards the ileum the effect decreases
how does the immune response relate to the gut metabolism simply
- Gliadin crosses epithelium into the lamina propria
- Deaminated by tTG which then presents to DQ2+ or DQ8+ cells antigen presenting cells to pathogenic CD4+ cells. DQ2/8 binds more strongly.
- Triggers immune response which results in inflammation
- Leads to villus atrophy
describe the histology of the gut in coeliacs disease
- Villus atrophy
- Crypt hyperplasia (increase in number of cells) whereas hypertrophy is an increase in the size of the cells
- Intraepithelial lymphocytosis – this is the increase in the number of inflammatory cells in the lamina
- This causes a decrease in surface area which causes a decrease in absorption
how do you diagnose coeliacs disease
Duodenal biopsy
- examined under post-absorptive state under mild sedation
- direct visual of the mucosa of the oesophagus, stomach,
duodenum
Immunology
- tissue transglutaminase (TTG) antibodies (IgA)
- endomyseal antibody (IgA)
how do you understand the blood test results
- Haemoglobin is low due to iron deficiency
- Haematocrit is low due to iron deficiency
- Mean corpsular volume is low due to microcytic anaemia
- Ferratin is low due to iron deficiency
- Calcium is low due to osteomalacia
- Alkakine phosphate is high due to osteomalacia
- Folate is low due to poor absorption
- IgA anti-tTG is high due to reaction to gliadin
What’s the microanatomy and the anatomy of coeliac disease
- Dudodenum – pancreatic enzyms and bile secreted as well as site of iron absorption
- Jejunum – main site of absorption, large surface area, plicae circulares (intestinal folds), villi and microvilli
- Ileum – terminal ileum is the site of vitamin B12 absorption
How are carbohydrates absorbed
broken down by brush border enzymes into glucose, lactose and
galactose
how are proteins absorbed
Broken down by pepsin and trypsin and other proteases
forms amino acids at the brush border
