Haem tutorial Flashcards
2 year old Swollen tender knee Happened following minor fall Afebrile, Small bruises
WBC shows not sepsis
Anaemic
Normal platelets (150-400)
Common cause of anaemia in chilren
Iron deficiency (fast growth)
PT tests what
Extrinsic pathway
(you get damaged, triggers extrinsic pathway)
ie. TF, FVII complex, increases factor X with FVa, then converts prothrombin to thrombin, which generates fibrin from fibrinogen
APTT tests what
Intrinsic pathway
(happens all the time inside you, shear generated from blood flow is damaging blood vessels many times a day)
FVIII, FIX, FXI, FXII
then the
How are the tests set up
PT: you get plasma, put tissue factor in, and then plasma goes from transparent to opaque (due to fibrin)
APTT: you get plasma, and use chemical to activate the intrinic athway, and again you look for fibrin
There is a problem in the intrinsic pathway
…….
What does thrombin time test
Time taken to convert fibrinogen to fibrin
shows there isn’t a problem with fibrinogen causing the elongated APTT
What is APTT 50/50 mix
Increased APTT due to i. lack of factor ii. inhibitor (antibody stopping the clotting factor from working)
Takes sample of plasma, adds half of the boy’s plasma, and half of normal plasma
If there is deficiency, then the APTT will correct (as you’ve added)
If there are antbodies against the factor, then the APTT will not increase (as the added factor will just be inhibited by the boy’s plasma)
Why does haemophilia cause anaemia
Due to the bleeding out of the vessel into the joints etc.
Which is more common haemophilia
Hemophilia A (factor VIII)
Isolated APTT is haemophilia likely…
……
What is treatment for haemopholia
Less than 1% FVIII then you have to inject regularly
FVIII half life is very short so has to be injected every other day
Pattern of bleeding in haemopholia
Deep and delayed
Jaundice causes
Prehepatic -UNconjugated bilirubin (before liver problem- haemolysis/gilberts (glucoronyl tranferase deficiency)
Hepatic (liver problem)- hepatitis (viruses/drugs), cirrhosis,
Post hepatic- CONJUGATED (doesn’t go into the stools, comes out of the bile duct and leaks into the blood and urine), gall stones (pain) or head of pancreas cancer (no pain)
Typical exam question
Explain why someone with posthepatic jaundice might have prolonged cloting time
Because poor absorption of vitamin K (fat soluble), which is needed to activate 2,7,9 and 10…… because you have blockage of bile duct so not enough bile salts
Why are APTT and PT increased
Because there is lack of factors in instric and extrinsic pathway (2,7, 9 and 10)
What does the normal TT tell you
That there is normal syntheti funcion (fibrinogen)
How would you treat
Give vitamin K (IV NOT IM, because you will bleed into the muscle)
You can give group O to group A. Will the antibodes from the donor blood haemolise the receiver antibody?
NO, because only red cells are given, not the plasma (which contains the antibodies)
What blood products do you not give to female of childbearing age
No Rh+ (she will become sensitised, and therefore if she has bab and the baby is RhD+ from the father, there will be disease of newborn)
Polychrmatic cell= reticulocyte
….
Direct antiglobulin test
Test for antibodies attached to the red cell
