Fichas
Anaemia
Fichas del conjunto (25)
- 1Describe the overall structure of haemoglobin.Tetramer consisting of 4 protein globin chains and a haem ring.
- 2Describe the genetics of haemoglobin.Chromosome 16: 2 areas that produce alpha chains.
Chromosome 11: non-alpha chains - 3Describe the differences in Hb structure through development.- At 12 weeks gestation embryonic Hb switched for foetal Hb (HbF).
- After birth HbF slowly replaced by HbA and HbA2
(HbF has a higher affinity for oxygen than HbA in order to transfer oxygen from the mother to foetus). - 4HbF.2 alpha, 2 gamma
- 5HbA.2 alpha, 2 beta
- 6HbA22 alpha, 2 delta.
- 7Post-translational modifications of Hb. Carboxyhaemoglobin.Binding of CO at the O2 binding sites. Fatal in high doses.
Higher in smokers. - 8Post-translational modifications of Hb. Carbaminohaemoglobin.Normal to have. CO2 complexed with Hb. Accounts for 10% of CO2 carriage.
- 9Post-translational modifications of Hb. Methohaemoglobin.Hb containing ferric form of iron (Fe3+) rather than ferrous.
Normal to have <2%. Symptoms occur if reaches 10%.
Cannot carry oxygen until reduced by metHb reductase.
Can be precipitated by some drugs eg. trimethoprim. - 10Post-translational modifications of Hb. Sulphaemoglobin.Cannot carry oxygen. Cannot be reversed.
Caused by sulphur containing drugs. - 11What are the causes of microcytic anaemia? <83fLIron deficiency
Thalassaemia
Anaemia of chronic disease - 12Where is iron absorbed?Duodenum.
- 13What are the presentations of iron deficiency?Angular stomatitis.
Sore mouth.
More uncommon: koilonychia, pharyngeal and oesophageal webs. - 14What are the lab features of iron deficiency?- Microcytic hypochromic anaemia: cells appear pale. Central pallor >1/3 of cell size.
- "Pencil cell": RBC appear long and oblong shaped.
- Low serum ferritin and iron.
- Low iron stores in bone marrow
- Increased TIBC and serum transferrin - 15What are the causes of normocytic anaemia?- Acute blood loss
- Haemolysis
- Bone marrow infiltration
- Anaemia of chronic disease
- Combined haematinic deficiency - 16What happens in anaemia of chronic disease?There is EPO suppression. ->
Reduced RBC survival. Iron sequestration in macrophages and failure to transport to the erythroblasts.
Treat: EPO + Fe. - 17What causes macrocytic anaemia?- B12/folate deficiency
- Hypothyroidism
- Alcohol excess
- Liver disease
- Myelodysplastic
- Haemolysis. - 18How is Vitamin B12 absorbed?Combines with intrinsic factor and is then absorbed at the terminal ileum.
- 19What does lack of IF cause?Pernicious anaemia.
- 20What are the clinical features of VitB12 deficiency?Glossitis; neurological deficits; jaundice; anaemia.
- 21What is the pathophysiology of Vitb12 deficiency?Anaemia results from inhibition of DNA synthesis.
Jaundice is related to the reduced cell survival. - 22Where is B9 absorbed?Jejunum.
- 23What drugs can cause B12 deficiency?Anti-convulsants.
- 24How do you treat vitamin B12 or folate deficiency?B before F!!!
Otherwise risk of subacute degeneration of the cord (with permanent neurological sequelae). - 25What is combined haematinic deficiency?If you have B12 deficiency and iron deficiency this can appear normocytic.
Important to look at the blood film
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- Haematology Fichas sobre Anaemia, creado por Katherine Chin el 09/06/2018.
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- Katherine Chin
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