Flashcards in Thalassaemia, Sickle Cell and Anaemia Deck (37):
HbA= a2b2 adult Hb
HbF= a2y2 fetal Hb (switch at 3-4 months)
HbA2= a2d2, 2% of adult Hb
type of anaemia produced by thalassaemia
how to differentiate between iron deficiency and thalassaemia anemia
IRON: pencil cells, more anisocytosis and anisopoikilocytosis. elevated RDW. reduced RCC
THALASSAEMIA BETA MINOR: RDW normal, RCC normal, minor elevation of HbA2.
what is RDW?
indicates variability of size and shape of rbcs
raised HbA2 in presence of hypochromic microcytic anemia would indicate
beta thalassaemia minor
what is alpha thalassaemia major? what Hb is present?
lost all the alpha genes.
presence of y4 Hb Barts. leads to Barts hydrops fetalis
what is HbH
4 beta chains present in alpha thalassaemia
type of anemia caused by alpha thalassaemia minor
how do we diagnose alpha thalassaemia minor
its hard because HbH and Barts are often not elevated to detectable levels
where is sickle cell most prevalent?
subsaharan africa eg. nigeria. should screen for sickle cell
what happens to sickle cells as they pass through the microcirculation
they sickle up, become less deformable, increase blood viscosity and can affect oxygen deliver to brain kidneys luigns spleen. can get infarctions.
cause of chest syndrome in sickle cell
necrosis of lung parenchyma
cause of renal infarction in sickle cell
sickle cells get lodged at the bottom of loop of henle where oxygen is lowest
consequences of neonatal sickle cell disease
initially protected due to HbF but then get abnormal growth and bone developemnt, more vulnerable to viruses
treatment of sickle cell
-raise HbF (hydroxyurea, butyrates)
-transfusion (iron overload? need chelator therapy)
why do we check for sickle cell before general anaesthesia
grave consequences, very bad.
problems with regular transfusions for sickle cell patients
iron overload requiring chelator therapy
can make antibodies against other rare blood groups making blood matching very difficult
what is anisocytosis
variable size of rbcs
what is anisopoikilocytosis
variable size and shape of rbcs
3 mechanisms of anemia
what is transferrin
transports iron around the body, absorbs iron
what is ferritin
a storage protein of iron
also an acute phase protein
what is hepcidin
regulator of iron metabolism. regulates circulating iron, iron availble for utilisation by bone marrow
causes of excess iron
inherited conditions (hemochromatosis)
side effects of iron replacement therapy
loss of appetitie
what is anaemia of chronic disease?
what type of anemia does it cause?
inflammatory environment increases the amount of hepcidin, this reduces the amount of iron available for utilisation by the bone marrow causing normocytic or microcytic anemia
findings on iron deficiency anemia of ferritin and transferring?
findings on chronic disease anemia of transferrin and ferritin
ferritin is normal
transferrin is low
5 findings of hemolytic anemia
-elevated lactate dehydrogenase
-change in rbc morphology
3 patterns of red cell morpholgy in haemolysis
-spherocytosis (hereditary or warm immune hemolysis)
-microangiopathy (fragmented red blood cell aka schistocyte)
-oxidative (bite cells and blister cells)
what pattern of morphology does G6PD produce in rbcs
oxidative with bite and blister cells
how can we test if anemia is immune mediated?
direct coombs test to find anti-red cell antibody bound to rbcs
what is a reticulocyte
cell before erythrocyte, have nucleic acid but no nucleus
what is microangiopahty
fragmented red blood cells on film, schistocytes etc
what is aplastic anemia
how do you differentiate from hemolytic?
marrow has stopped making rbcs,
hemolytic will have reticulocytosis
what causes macrocytic anemia
folate or B12 deficiency