haematology formative learning points Flashcards
pathophysiology of sickle cell disease?
point mutation in the beta chain and this predisposes the haemoglobin to polymerise resulting in sickled cell
what forms HbS and what disease does it cause
glutamic acid to valine substitution in the beta chain of haemoglobin
2x HbS causes sickle cell disease, 1 causes sickle cell trait which will only cause effect in times of stress
what forms HbA2
2 alpha chains and 2 gamma chains
how does clopedigrel work?
Clopidogrel selectively inhibits the binding of adenosine diphosphate (ADP) to its platelet receptor, stops activation of glycoprotein GPIIb/IIIa complex thereby irreversibly inhibiting platelet clumping
how does aspirin work
inhibit the activity of the enzyme now called cyclooxygenase (COX) which irreversibly stops production of thromboxane (and stops prostaglandin production)
describe a eosinophil
pink with granules and bilobed (basophil is purple)
describe a monocyte
purple with kidney bean shaped nucleus
The blood film shows macroovalocytes and hypersegmented neutrophils… what is diagnosis?
b12/ folate deficiency
what are auders rods and what are they found in?
distinct needle like crystals that contain peroxidase found in RBC
acute myeloid leukemia
how does rituximab work?
monoclonal antibody directed against CD20, expressed on B cells and B cell lymphomas
how does imatinib work?
tyrosine kinase inhibitor that is inhibits BCR-ABL-1 protein unique to chronic myeloid leukaemia
how does factor V leiden cause thrombophilia?
factor V (which normally helps clotting) is normally turned off by activated protien c and slows down clotting, when mutation in F5 gene APC no longer works on factor 5
where does factor VIII work?
intrinsic pathway
vit k is?
Vitamin K is absorbed in the upper intestine, responsible for bile salt absorption, carboxylates specific preformed clotting factors, is antagonised by warfarin, fat soluble
what causes a Febrile non-haemolytic transfusion reaction
antibodies directed against donor leukocytes and HLA antigens present of cytokines
what type of patients does a transfusion associated circulatory overload (TACO) occur?
chronic anaemia and a compensatory high cardiac output and causes a pulmonary oedema
transfusion related acute lung injury
happens when donor anti leucocyte antibodies bind to the patients white cells and cause degranulation. pulmonary infiltrate can be seen on CXR
what would you see in autoimmune haemolytic anaemia?
Direct antiglobulin test (Coombs’ test) strongly positive, reticulocytosis and serum lactate dehyrogenase
when would you see bence jones protiens?
multiple myeloma due to the excretion of ig light chains
when are smudge cells seen?
CLL
what clotting results would you get in a patient with vWB disease?
decreased factor VIII activity, normal PT time, and prolonged APTT, and prolonged bleeding time
Howell–Jolly bodies
single peripheral bodies within red cells representing DNA material seen in splenectomy/ functional hyposplenism
haemophillia a=… b =…
a= deficiency in factor VIII
b= deficiency in factor IX
how does warfarin work?
inhibits II, IX, X, VII and prothrombin (aswell as protein c and s)
multiple myeloma being about b cells vs lymphoma
ask katie
what does heparin inhibit
Xa and thrombin
