haematology formative Flashcards
what is the direct coomb’s test
used to detect antibodies attached to the surface of RBC
when would you use the direct coombs test
autoimmune haemolytic anaemia
rhesus compatability
acute haemolytic reaction
sickle cell
what is haemoglobin analysis by high performance liquid chromatography (HPLC) used for
used to identify the different types of haemoglobin present in the blood
- thalassaemias
microcytic anaemia found at antenatal clinic- investigation?
HPLC of hb to look for thalassaemia
normal or low hb, raised WCC, normal or low platelet count
chronic lymphocytic leukaemia
key investigation for chronic lymphocytic leukaemia
Immunophenotyping by flow-cytometry
- looks for antigens on the WBC
what is osmotic fragility test used for
hereditary spherocytosis and thalassaemia
causes of hereditary thrombophilias
factor V leiden- most common
prothrombin 202010 mutation
antithrombin deficiency
protein C deficiency
protein S deficiency
aetiology of sickle cell anaemia
point mutation in codon 6 of the beta globin gene that substitutes glutamine to valine
defintion of sickle syndromes
group of genetic disorders that affect the structure of haemoglobin
resulting in the production of HbS
what is myelodysplasia
acquired DNA mutations in haematopoietic stem cells
immature blood cells in the bone marrow do not mature to become healthy blood cells
definition of thalassaemia
autosomal recessive inherited disorders of haemoglobin causing reduced globin chain synthesis, resulting in impaired haemoglobin production
definition of hereditary spherocytosis
mutation in one of the structural red cell membrane proteins resulting in reduced red cell deformability and so membrane is removed in spleen and reduced red cell survival
where is vitamin K absorbed
upper intestine
- require bile salts for absorption
what factors are carboxylated by vit K
factors II, VII, IX, and X
causes of vit K deficiency
poor dietary intake
malabsorption
obstructive jaundice
vit k antagonists (warfarin)
haemorrhagic disease of the newborn
mechanism of action of clopidogrel
selectively inhibits the binding of adenosine diphosphate (ADP) to its platelet receptor and the subsequent ADP-mediated activation of the glycoprotein IIb/IIIa complex
= inhibiting platelet aggregation
basically is a ADP antagonist
aspirin mechanism of action
Inhibits cyclo-oxygenase which is necessary to produce thromboxane A2 (a platelet agonist released from granules on activation)
mechanism of action of dipyridamole
Phosphodiesterase inhibitor - increases production of cAMP which inhibits platelet aggregation
mechanism of action of heparin
potentiates antithrombin
mechanism of action of warfarin
inhibition of vit K
factors II (prothrombin), VII, IX and X (+protein C and S) require vit k for final carboxylation step essential for function
mechanism of action of riveroxiban
competitively inhibits factor Xa
factor Xa along with factor Va for the prothrombinase complex which converts prothrombin to thrombin
low Hb, platelets, neutrophils but high WCC and auer rods
acute myeloid leukaemia
mechanism of action of rituximab
complement-mediated cytotoxicity and antibody-dependent cell mediated cytotoxicity
targets CD20
mechanism of action of Imatinib
inhibits the enzyme activity of bcr-abl (?)
what does an isolated prolonged partial thromboplsatin time mean
deficiency of factors involved in the intrinsic pathway of coagulation or presence of anti-phospholipid antibody
- VIII/IXa
what does an isolated prolonged prothrombin time reflect
deficiency of factors involved in the extrinsic pathway but not common
= factor VII
uncontrolled production of essentially normally functioning blood cells
polycythaemia vera
uncontrolled production of immature blood cells in the bone marrow
acute myeloid leukaemia
clonal B cell disorder usually resulting in a large number of circulating malignant cells
chronic lymphocytic leukaemia
fever but no haemolysis post transfusion
febrile non-haemolytic transfusion reaction
first line treatment of autoimmune haemolytic anaemia
steroids- prednisolone
folic acid
features of autoimmune haemolytic anaemia
anaemia
reticulocytosis
low haptoglobin
raised LDH
spherocytes and reticulocytes
management of chemo inducing pancytopenia
red cell transfusion
red cells that have lost central pallor
spherocytes
