Haematology Flashcards
(33 cards)
Describe erythropoiesis?
In the bone marrow, erythropoiesis takes place, through a series of differentiation steps, haematopoietic stem cells become reticulocytes. Reticulocytes remain in the bone marrow for 3 days before they are released into the circulation.
After circulating in the blood for 1 day, they transform into fully mature RBC, which circulate for around 120 days before being removed by macrophages.
how can anaemia be classified?
Microcytic (MCV <80)
Normocytic
Macrocytic (MCV > 100)
what are causes of microcytic anaemia?
iron deficiency anaemia
haemoglobinopathies - thalassemia
inflammation - chronic inflammation can cause anaemia
lead poisoning
copper deficiency
sideroblastic anaemia
what is the role of iron in the body?
enzymatic processes
DNA synthesis
oxygen transport
mitochondrial energy generation
describe how iron is absorbed into the body?
iron is typically ingested in Fe3+ form. This cannot be absorbed by the small intestine lumen, and therefore is converted at the small intestine cells to Fe2+ which can easily be absorbed.
Once absorbed, it is converted back into Fe3+, and transported around the body via transferrin.
The iron is taken to either the bone marrow, where iron is used by haemoglobin to carry oxygen. Some of the iron is also taken to the liver, where the liver can store iron as ferritin.
what is the role of transferrin?
to transport iron (ferritin) around the body.
what factors regulate iron concentration in the plasma?
hepicidin - this is produced by the liver, and typically will work to limit iron release into circulation.
what is tested for in blood iron studies?
iron studies - ferritin, transferrin, serum iron, TBIC
what does iron deficiency anaemia show on iron studies blood tests?
MCV - low
serum iron - low
ferritin - low
transferrin - elevated (this is to compensate for the low ferritin)
TBIC - high
what is the role of vitamin b12 in the body?
DNA synthesis in RBC’s, and regulation of the nervous system
what are the causes of vitamin b12 deficiency?
pernicious anaemia
malabsorption - coeliac/GI surgery/chronic pancreatitis
drugs - metformin/PPI/H2antagonist
inadequate dietary intake
what is pernicious anaemia?
autoimmune disorder where antibodies are produced to gastric parietal cells and intrinsic factor
how does vitamin b12 deficiency present?
sore tongue + mouth - atrophic glossitis
neurological sx - fatigue, peripheral neuropathy
management of pernicious anaemia?
if no neuro features - 3 IM vitamin b12 inj per week for 2 weeks, then 3 monthly after that
more frequent doses given if neuro features present
replace folate
how is haemophilia inherited?
X linked recessive
what are the two different types of haemophilia?
type A - factor VIII deficiency (most common)
type B - factor IX deficiency (christmas disease)
symptoms of haemophilia?
haemoarthroses
haematomas
prolonged bleeding after injury/surgery
what would you see on the blood results for haemophilia?
prolonged APTT
PT/INR normal
plts normal
management of haemophilia?
haem ref
tranexamic acid
desmopressin - stimulates factor VII
how is VWD inherited?
autosomal dominant
what are the symptoms of von willerband disease?
menorrhagia
epistaxis
easy bruising
haemoarthroses
what would blood tests show for von willerbrand disease?
APTT prolonged
Plts normal
factor VII levels low
management of von willerbrands?
refer to haem is suspected
tranexamic acid / desmopressin
mirena for menorrhagia
what are the causes of prolonged APTT?
von willerbrand
haemophilia A
haemophilia B
DIC
unfractionated heparin tx
