malabsorption Flashcards
list the 3 causes of low MCV anaemia
Iron deficiency
Thalassaemia trait
Anaemia of chronic disease
what are the results for the following in iron deficiency anaemia:
Hb Serum Iron TIBC or Transferrin Transferrin saturation Ferritin
Hb - Low Serum Iron - low TIBC or Transferrin - high Transferrin saturation - low Ferritin - low
what are the results for the following in Thalassaemia trait:
Hb Serum Iron TIBC or Transferrin Transferrin saturation Ferritin
every thing is normal
Hb may be low or normal
what are the results for the following in Anaemia of chronic disease:
Hb Serum Iron TIBC or Transferrin Transferrin saturation Ferritin
every thing is normal
apart from Hb and serum iron which are both LOW
give examples of red cell morphology that may be seen on blood film in Iron deficiency ?
Tear drop cell/poikilocytes
Elliptocyte
Target cells - Codocytes
Basophilic stippling (Aggregated ribosomal material) is visualised in which conditions?
Beta thalassaemia trait
Lead poisoning
Alcoholism
Sideroblastic anaemia
what is the characteristic blood film finding for the following:
B12 deficiency
Folate deficiency
Drugs
Hypersegmented neutrophil :
Megaloblastic anaemia - reflects impaired DNA synthesis
Target cells - Codocytes may be seen in which conditions?
Iron deficiency
Thalassaemia
Hyposplenism
Liver disease
Howell-Jolly bodies - Nuclear remnants visible in red cells, are seen in which condition?
Hyposplenism
list the blood film features indicative of Hyposplenism?
Howell-Jolly bodies
Target cells - Codocytes
list the causes of hyposplenism?
Absent spleen - Therapeutic
- Trauma
Poorly-functioning spleen
- Inflammatory bowel disease - Coeliac disease - Sickle cell disease - SLE
which deficiencies are seen in the following condition:
Coeliac disease
Iron, B12, Folate, Fat, Calcium - all rounder
Vitamin D and Vitamin K deficiency
which deficiencies are seen in the following condition:
Crohn’s disease
bile salts, b12
which deficiencies are seen in the following condition:
Pancreatic disease
fat, calcium, B12
which deficiencies are seen in the following condition:
Infective/Post-infective
fat / folate
what are the genetic associatoins for coeliac disease?
90% patients carry HLA DQ2
(DQA10501 and DQB102 alleles)
Other patients carry HLA DQ8
what is the mechanism involved in coeliac disease ?
gluten allergy - t cell mediated response
- Peptides from wheat /gliadin are deamidated by tissue transglutaminase (TTG) and presented by APC via their HLA DQ2 or DQ8 receptors
- CD4 T cells recognise these deamidated peptides and become activated
- CD4 T cell activation = IFN-g n possibly IL-15 secretion
- Cytokines -> activation of the intra-epithelial lymphocytes (gd TCR IEL) which kill epithelial cells via their NKG2D receptors
The activation of the intra-epithelial lymphocytes appears to be independent of engagement of their T cell receptor
antigen -> apc -> T cell -> IEL -> cell destruction
apart from producing IEL, what are other roles do activated cd4 Lymphocytes play in response to gluten?
activate B cell with surface receptors for gliadin and TTG
resulting in b cell maturation and plasma cell formation
leading to productoin of anti-gliadin antibodies and anti-TTG antibodies and anti-endomysial
what are the sensitivites of antibodies in coeliac disease?
IgA anti-transglutaminase antibody
90-94%
IgA anti-endomysial antibody
85-94%
IgG or IgA anti-gliadin antibody
57-80%
what is the First line immunological test for coeliac disease in most laboratories?
IgA anti-transglutaminase antibody
which antibody may be detectable up to 12 months after institution of gluten-free diet?
anti-gliadin
the others dissapear after a few months
Is duodenal biopsy necessary to diagnose coeliac disease?
Duodenal histology remains the “gold standard”
but should correlate it with serology
what would Histopathology of coeliac disease show?
Villous height is reduced (atrophy) and crypt thickness is increased (hyperplastic).
In coeliac disease, this is increased to >25 intra-epithelial lymphocytes (IELs) /100 epithelial cells *
*in the proximal small intestine
name some Other causes of increased intra-epithelial lymphocytes ?
Infections - giardia, H. pylori
Drugs - NSAIDs
Immune conditions - SLE, IgA deficiency
IBD
