Week 3 Flashcards
Describe where haemopoiesis occurs in the foetus
0-2 months - yolk sac
2-7 months - liver, spleen
5-9 months bone marrow
Where does haemopoeisis occur in infants?
bone marrow of all bones
Where does haemopoiesis occur in adults?
the axial skeleton bone marrow
vertebrae, ribs, sternum, skull, sacrum, pelvis, ends of femurs
what can pluripotent stem cells become?
myeloid stem cells and lymphoid stem cells
What do myeloid stem cells differentiate into?
erythroblasts
megakaryoblasts
monoblasts
myeloblasts
What do erythroblasts differentiate into?
reticulocytes then erythrocytes
What do megakaryoblasts differentiate into?
megakaryocytic then platelets
What do mono blasts differentiate into?
monocytes and macrophages
What do myelocblasts differentiate into?
myelocytes then neutrophils, eosinophils and basophils
What do basophils differentiate into?
mast cells
What do lymphoid stem cells differentiate into?
B cells (plasma cells) and T cells
Where are haematopoietic stem cells found?
bone marrow
peripheral blood after growth factor treatment
umbilical cord blood
Describe the bone marrow microenvironment
Stroma cells - macrophages, fibroblasts, endothelial cells, fat cells, reticulum cells.
Supported by ECM of fibronetin, proteoglycans and collagen
What hormones regulate erythropoiesis?
EPO
thyroxine
testosterone
What are the paracrine regulators of granulopoiesis?
microenvironment
growth factors
chemokine
cytokines
Describe bone marrow aspirations
posterior iliac spine in adults
predominantly granulocytes
best way to look for leukaemias
Describe bone marrow trephine
biopsy used to analyse the architecture of the bone marrow
good for looking for marrow infiltration - cancer / fibrosis
Describe the principles of leukaemogenesis
multi-step process
neoplastic cell is haematopoietic or early myeloid or lymphoid cell
dysregulation of cell growth and differentiation associated with mutations that confer growth advantage to LSC
What is meant by myeloproliferatve disorders?
clonal disorders of haemopoiesis leading to increased numbers of mature blood progeny
What are the classical MPDs?
polycythaemia rubra vera
essential thrombocytosis
myelofibrosis
Describe myelodysplastic syndromes
characterised by dysplasia and ineffective haemopoiesis of the myeloid series
What can MDS’s lead to?
progressive bone marrow failure i.e cytopaenias
some progress to AML
What are the clinical features of MDS?
mainly elderly
infarctions or bleeding
fatigue - anaemia
What are the types of stem cell transplant?
autologous
allogeneic
What are the types of allogenic stem cell transplants?
syngeneic transplant - identical twins
allogeneic sibling - HLA identical
volunteer unrelated
umbilical cord blood
What are the main indications for autologous stem cell transplant?
relapsed Hodkin’s disease, non hodgkin’s lymphoma
myeloma
What are the main indications for allogenic stem cell transplant?
acute leukaemia, aplastic anaemia, hereditary disorders
How does graft-versus-host disease commonly present?
skin rash, jaundice, diarrhoea
What are the advantages of using umbilical cord blood?
more rapidly available than VUD
less rigorous matching to patient as immune cells in cord blood are immune naive
What are the disadvantages of using umbilical cord blood?
small amount
slower engraftment
if replace can’t go back for DLI
What are the problems with stem cell transplant?
limited donor availability not available to old immunosuppression infertility cataract formation hypothyroidism, dry eyes and mouth risk of secondary malignancy osteoporosis / avascular necrosis relapse
What is the problem with measuring serum ferritin to determine IDA?
it is an acute phase protein
Describe RES storing of iron
effete rbcs are removed by macrophages of the RES
500mg stored iron in ferritin/haemosderin
released to transferrin in plasma
Tf iron taken up via Tf receptors on erythroblasts, hepatocytes etc
What does low serum ferritin indicate?
low RES iron stores
When can serum ferritin levels appear normal even when IDA exists?
in the presence of tissue inflammation - e.g. RA and IBD
What is spooning of the nails called?
koilonychia
What are some of the clinical effects noticed in the head and neck in IDA?
atrophic glossitis
angular stomatitis
oesophageal web
What are the causes of IDA?
dietary
malabsorption
blood loss
What is the golden rule when deciding the cause of IDA?
in males and post -menopausal females IDA is due to GI blood loss until proven otherwise
Describe anaemia of chronic disease
failure of iron utilisation
iron trapped in RES
common
causes - infection, inflammation, neoplasia
What is the pathophysiology of ACD?
RES iron blockade
reduced EPO response
depressed marrow activity; cytokine marrow depression
What is B12 needed for?
methylation of homocysteine to methionine
methylmalonyl CoA isomerisation
Describe B12 absorption
Ingested as animal protein
gastric parietal cells produce IF
B12 released by acid in stomach and duodenum
IF binds to B12
This binds to cubulin in the ileum
B12 is absorbed and binds to transcobalamin
What are the dietary sources of folate?
green veg
how is folate abosorbed?
freely (no carrier molecule needed)
What are the tissues effected by B12 or folate deficiency?
bona marrow
epithelial surfaces - mouth, stomach, small intestine, female genital tracts, urinary
Describe clinical B12 deficiency
blood abnormalities - megaloblastic anaemia (leukocpaenia, thrombocytopenia) neurological manifestations (bilateral peripheral neuropathy or demylination of the posterior and pyramidal tracts of the spinal cord
Describe clinical folate deficiency
blood abnormalities - megaloblastic anaemia growing foetus (1st 12 weeks - neural tube defects)
How do patients present with folate and B12 deficiency?
symptoms of anaemia and cytopaenia - tired
easy brushing
mild jaundice
neurological problems
what is foetal Hb made up of?
alpha 2 and gamma 2
What is adult Hb made up of?
alpha 2 and beta 2
What are thalassaemias?
relative lack of globin genes
Where are alpha and beta globin genes normally found?
4 alpha (on 2 Ch16) 2 beta (on 2 Ch11)
What is the alpha+ trait?
one missing alpha gene
mild microcytosis
What is homozygous alpha+ trait?
two missing alpha genes (1 from each parent)microcytosis, increased red cell count and sometimes very mild anaemia
What is HbH disease?
3 missing alpha genes
significant anaemia and bizarre shaped small red cells - beta tetromeres form
What is alpha thal major?
no alpha genes - not compatible with life
What is the alpha 0 trait?
2 missing alpha genes (both from same parent)
Describe HbH disease
missing 3 alpha chains
excess beta chains
beta chains join together
blood transfusion required during periods of stress
Describe beta thalassaemia major
missing both beta globin genes autosomal recessive unable to make adult Hb significant dyserthropoiesis transfusion dependent from early life iron overload has major effect on life expectancy
Describe the pathogenesis of sickle cell disease
chromosome 11
single amino acid substitution on B globin gene at position 6
glutamine >valine = HbS
HbS 2 alpha + 2 beta (sickle) (alpha2betas2)
What does the polymerisation of HbS depend on?
deoxygenation rate
Hb concentration
HbF
What is the clinical result of sickle cell disease
haemolysis
vaso-oclusion - tissue hypoxia / infarction
How does sickle cell affect the brain?
stroke
moya moya
how does sickle cell affect the lungs?
acute chest syndrome
pulmonary hypertension
how does sickle cell affect the bones?
dactilytis
osteonecrosis
how does sickle cell affect the spleen?
hyposplenic
how does sickle cell affect the kidneys?
loss of concentration
infarction
how does sickle cell affect the urogenital tract?
priapism
how does sickle cell affect the eyes?
vascular retinopathy
how does sickle cell affect the placenta?
IUGR
foetal loss
What is the treatment of sickle cell disease?
prevent crises - hydration, analgesia, early intervention, vaccination and antibiotics, folic acid
prompt management of crises - oxygen, fluids, analgesia, antibiotics, specialist care, transfusion / red cell exchange
bone marrow transplantation
What is haemolytic anaemia?
anaemia related to reduced RBC lifespan
no blood loss
no haematinic deficiency
Describe hereditary spherocytosis
autosomal dominant
RBCs spherocytic and polychromatic
jaundice
splenomegaly
What should be given to a patient who has had a splenectomy?
pneumococcus, meningococcus vaccinations and long term penicillin V
Describe the compensated haemolytic state
20-100d
Hb normal
raised reticulocytes
raised bilirubin
Describe non-compensated haemolytic anaemia
low Hb
increased reticulocytes
increased bilirubin
splenomegaly
Describe pyruvate kinase deficiency anaemia
chronic / extravascular haemolytic anaemia
ATP depletion
autosomal recessive
Describe glucose 6 phosphate dehydrogenase deficiency
acute episodic intravascular haemolysis
x linked recessive
acute haemolysis from oxidative stress -fauvism, drugs (antimalarials, sulphonamides etc)
What are the types of acquired haemolytic anaemias?
autoimmune- warm and cold
isoimmune - mother on baby
non immune - fragmentation haemolysis
Describe cold AIHA
autoantibody IgM (+complement)
mycoplasma infection
idiopathic
forms agglutinins
Describe warm AIHA
autoantibody IgG (+/- complement) other autoimmune disease lymphoproliferative disorder (NHL/CLL) drug induced RBCs spherocytic and polychromatic
What is the purpose of a direct coombs test?
to detect antibody on RBC surface
What is the purpose of an indirect coombs test?
to detect RBC antibodies in plasma
What is the treatment of cold AIHA
self limiting mycoplasma
idiopathic -keep warm
What is the treatment for warm AIHA?
stop any drugs
steroids
immunosuppression
splenectomy
What is leukaemia?
accumulation of abnormal leukocytes in marrow and blood/ other tissues
What do the symptoms of chronic leukaemia result from?
accumulation of cells
What do the symptoms of acute leukaemia result from?
from marrow failure
What does MDS stand for?
myelodysplastic syndrome
How is MDS characterised?
failure of effective haemopoiesis (low blood counts) most common in elderly dysplastic marrow and blood appearances 25% transformation to AML consequences of marrow failure
What does MPD stand for?
myeloproliferative disorders
What is the term for too many platelets?
essential thrombocytopaenia
What is the word for too many red cells?
polycytheamia vera or primary polycythaemia
What is the name for too much fibrous tissue?
myelofibrosis
Describe ET and PRV
good outcome risk of vascular events (aspirin) cytoreduction (hydroxycarbamide, venesection or interferon) 5-10% risk of AML 10% progress to myelofibrosis
Describe myelofibrosis
difficult, large spleen, systemic symptoms, blood counts high or low, incurable other than SCT. JAK2 inhibitors
Describe acute leukaemia
clonal disorders
blastic proliferation in bone marrow “maturation arrest”
rapid in onset
serious compromise of normal marrow elements
death within days or weeks if untreated
What are the different classes of AML?
erythroleukaemia
myeloid leukaemia
monocytic leukaemias
megakaryocytic anaemias
What are the different classes of ALL?
T lymphoblastic B lymphoblastic (more common)
Describe the history and examination in acute leukaemia
rapid onset lethargy infection bleeding and bruising bone pain gum swelling lymphadenopathy skin rash
What is seen in peripheral blood in leukaemia?
anaemia
neutropenia
thrombocytopenia
blasts
What is the translocation in M3 AML?
t(15:17)
What is the translocation in m2 AML?
(8:21)
What are the three choices for the management of AML?
intensive chemotherapy +/- SCT
low dose chemotherapy
supportive care only
What is the typical clinical presentation of ALL?
the limping child
purpuric rash
unexplained, sometimes severe bone pains not uncommon
lumps vs liquid presentation
What are common translocations in ALL?
(9: 22)
4: 11
why is CNS chemotherapy essential in ALL?
CNS and testes are common sanctuary sites for leukaemic cells
What is the supportive care involved in ALL treatment?
blood transfusions fresh frozen plasma platelet transfusion antibiotics growth factors granulocytes
Which patients are more likely to receive a transplant for ALL?
relapsed patients refractory patients poor risk disease in first CR age less than 60 good performance
Describe the presenting features of CLL
none
lethargy, night sweats, weight loss
lymphadenopathy
infection
Describe 17p deletions in CLL
aggressive disease
refractory to chemo
loss in p53
patients may respond to steroids and antibodies
What are the immune complications of CLL?
autoimmune haemolytic anaemia autoimmune thrombocytopenia at presentation precipitated by treatment treat with steroids treat CLL
What are the triggers to treat CLL?
symptoms
bone marrow failure
What are the symptoms of CML?
fatigue weight loss night sweats abdominal discomfort splenomegaly is very common
What is the main treatment of CML?
imatinib - blocks BCR-ABL
tyrosine kinase inhibitor
What is lymphoma?
malignancy derived from lymphocytes
presents with tumour mass
most commonly in lymph nodes
What are the two general categories of lymphoma?
hodgkins and non hodgkins
Describe low grade lymphoma
neoplastic cells mostly small
low proliferation
low apoptosis
slow accumulation of neoblastic lymphocytes
often widely disseminated at presentation
indolent clinical course
incurable
Describe high grade lymphoma
large neoplastic cells with activate "blast like" appearance dispersed nuclear chromatin prominent nucleoli high cell division tends to be localised at presentation often curable
What protein can be used to assess the rate that cells are dividing at?
Ki67 - expressed by cells in S phase
Describe follicular lymphoma
neoplasm of follicle centre B cells - centrocytes, centroblasts painless lymphadenopathy often generalised bone marrow frequently involved incurable
What is the treatment for follicular lymphoma?
alleviating symptoms
low dose chemotherapy
radiotherapy
What is a common mutation in follicular lymphoma?
t(14;18)
BCL2/IGH
BCL2 is an apoptotic protein
Describe Burkitt lymphoma
neoplasm of proliferating follicle centre b cells - centroblasts
What are the three epidemiological variants of burrito lymphoma?
endemic
sporadic
immunodeficiency asssociated
Describe endemic Burkitt lymphoma
equatorial africa and papa new guinae
malaria
strong associstion with epstein bar virus
most common childhood malignancy in these areas
Describe sporadic burkitt lymphoma
seen in western europe and north america
children and young adults
Describe immunodeficiency associated Burkitt lymphoma
HIV
post transplant
How does Burkitt lymphoma present?
mainly extranodal disease jaws and facial bonw ileocaecum ovaries kidneys breast CNS involvement is common
Describe the genetics in Burkitt lymphoma
most have chromosomal translocation involving MYC and IG gene
Describe diffuse large B - cell lymphoma
heterogeneous group
most common
mainly adults
Hows does diffuse large B cell lymphoma usually present?
rapidly enlarging mass at single nodal or extra nodal site
mainly at early stage
less responsive to therapy than Burkitt but aim is still to cure disease with aggressive chemo
How is hodgkin lymphoma characterised?
very large neoplastic B cell
Reed Sternberg cell
prominent background of relative white blood cells - lymphocytes, histiocytes, granulocytes
How does classic hodgkin lymphoma typically present?
often localised
mediastinal and cervical lymph nodes
contiguous spread
Describe the morphology seen in classic hodgkin lymphoma
very large b-cell with blast like morphology
abundant cytoplasm
binucleate
prominent nucleolus
What are the types of classic hodgkin’s lymphoma?
mixed cellularity
nodular sclerosing
lymphocyte rich
lymphocyte depleted
Describe the cell signature of reed sternberg cells
defective b cell
cd20 negative
PAX5 positive
What are the risk factors for lymphoma?
immunosupression
infection - EBV, helicobacter pylori
age
close relative
How is lymphoma staged?
CT
PET CT
bone marrow aspirant and biopsy
Describe the Ann Arbor staging system
I - single LN region
II - >2 LN areas, same side or diaphragm
III- both sides of diaphragm
IV - extensive disease e.g liver, bone marrow
What are B symptoms ?
drenching night sweets
significant weight loss
unexplained fever
What is myeloma?
cancer of the bone marrow plasma cells
How does myeloma present?
backache or rib pain fatiguw symptoms of hypercalcaemia recurrent infections renal impairment
What is meant by paraprotein?
abnormal plasma cells produce an abnormal monoclonal protein called paraprotein or M protein
What is the classical triad that typifies myeloma?
increased plasma cells in bone marrow
clonal immunoglobulin or paraprotein
lytic bone lesions
How is myeloma diagnosed?
blood tests - FBC, ESR,U&Es. , Calcium,serum protein electrophoersis
urine tests - light chains
bone marrow aspirate
imaging
What does MGUS stand for?
monoclonal gammopathy of undermined significance
What are the CRAB features which make myeloma patients high risk
calcium elevation
renal dysfunction
anaemia
bone disease
What happens when you cut yourself?
blood vessel damage
disrupt endothelium
exposure of tissue factor and collagen
primary haemostats - recruitment of platelets
secondary haemostats - activation of coagulation factos
occur simultaneously
What is the cascade of events that occurs in secondary haemostats?
initiation - extrinsic
propagation - intrinsic
thrombin generation
fibrin production - the clot
What is the main clotting facto involved in the extrinsic pathway?
VII
What factors are in the prothombinase complex?
Xa, II and Va
What are required at every step of the coagulation cascade?
phospholipid
calcium
What are the main factors involved in the intrinsic pathway?
XI, IX and VIII
How can primary haemostasis be assessed?
bleeding time
platelet function
How can secondary haemostasis be assessed?
prothrombin time
activated partial thromboplastin time
thrombin clotting time
individual coagulation factor assays
Why is citrate in a blood sample that is being testing for coagulation?
chelates all calcium and prevents a clot formation
What does the PT depend on?
factors in extrinsic and common pathways
factor VII
and X, V, II and fibrinogen
What is the INR?
international normalised ration
standardised form of prothrombin time
What does APTT depend on?
factors VIII, IC, XI and XII
and X< V, II and fibrinogen
What is the TCT
measurement of conversion of fibrinogen to fibrin clot
What does TCT depend on?
how much fibrinogen is present
how well it functions
What will TCT be prolonged by?
inhibitors of thrombin (heparin, dabagitran)
FDPs
inhibitors of fibrin polyerisation (paraproteins)
What can a long PT only suggest?
low factor VII
What can a long APTT only suggest?
low VIII, IX, XI or XII
lupus anti-coagulant
What does a low PT and APTT suggest
common pathway factor low
multiple low factors - liver disease, warfarin
What do anticoagulants do?
they inhibit one or several components of the coagulation cascade
What do fibrinolytic agents do?
chance lysis of fibrin clot
What do anti-platelet agents do?
inhibit platelet activation or aggregation
How do hepatitis and fondarinux work?
antagonise factor Xa
How does oral warfarin work?
vitamine K antagonist
lowers factors II, VII, IX and X
What is the mechanism of action of heparins?
mixture of glycosaminoglycans of differing polysaccharide chain length
augment activity of endogenous antirthrombin
does not cross placenta
short half life
administered parenterally
What are the potential side effects of heparin?
HIT - heparin induced thrombocytopaenia
osteoperosis
hyperkalcaemia
What are the advantages of LMWH?
superior pharmacokinetic profile allowing predictable dose repsonse safer side effect profile clinical efficacy atleast as good no monitoring out-patients
What are the indications for using heparin?
acute DVT or PE during cardiac bypass surgery acute coronary syndroemes medium term after VTE in cancer patients prophylaxis against VTE medical and post op patients obstetric patients
What pathway does warfarin inhibit?
vitamin K oxide reductase
What factors does warfarin effect?
II, VII, IX and X
What is the target INF on warfarin?
2-3
What is warfarin used for?
atrial fibrillation
acute DVT or PE
prosthetic heart valve
What is warfarin not for?
immediate anticoagulation
short term thromboprophylaxis
What is the name of the DOAC that inhibits factor IIa?
dabigatran
What is the name of the DOACs that inhibit Xa?
rivaroxaban
apixaban
edoxaban
What are contraindications for all DOACs?
pregnancy and breast feeding
liver disease with cirrhosis and some drugs
What are the 2 classes of fibrinolytic?
kinases
tissue plasminogen activators
describe the action of kinases
bind to plasminogen releases plasmin enhanced breakdown of fibrin causes both fibrinolysis and systemic fibrinogenolysis significant bleeding risk
Why is streptokinase antigenic?
derived from bacteria
recent strep infection or previous use of drug and render it ineffective
How do tPA derivatives work?
activate plasminogen plasmin cleaned from plasminogen plasmin breaks down fibrin relatively selective for clot bound plasminogen minimal unwanted fibrogenolysis
What are tPA derivatives used for?
acute MI (for patients not suitable for PCI)
ishaemic stroke
massive PE with haemodynamic instability
What are the uses of catheter directed thromblysis?
acute limb ischaemia
massive DVT
blocked CVC
What are the actions of anti platelet drugs and how are they achieved?
inhibit platelet activation
inhibit platelet aggregation
by receptor inhibition and platelet signalling pathway inhibition
Describe the action of clopidogrel and ticlodipine
irreversible blockage of ADP receptor
decreased depression of GPIIB/IIIa
reduced binding of fibrinogen
Describe the action of abciximab and tirofiban
GPIIb/IIIa antagonists
monoclonal antibodies
reduced platelet aggregation
reduced bidding of fibrinogen
Describe the action of aspirin
irreversible inhibition of cyclooxyrgenase
blocks conversion of arachidonic acid to thromboxane A2
decreased platelet activation
Describe the action of phosphodiesterase III inhibitoe
dipyrisamole
increased platelet concentration of cAMP
platelet responds less to ADP
reduced activation and aggregation of platelets
Describe medication indicated following acute MI
aspirin indefinitely
ticagrelor/clopidogrel for up to 12 months
What is DIC?
disseminated intravascular coagulation. acquired consumptive process activation of coagulation cascade micro thrombi exhaustion of coagulation cascade bleeding
What are the causes of DIC?
sepsis malignancy massive haemorrhage severe trauma pregnancy complications e.g. pre-eclampsia, placental abruption, amniotic fluid emobolism
what can DIC cause?
systemic activation of coagulation
intravascular fibrin deposition
thrombosis of small and midsize vessels and organ failure
depletion of platelets and coagulation factors
bleeding
What laboratory investigations would you do for DIC?
coagulation PT, APPT, fibrinogen
D dimers
FBC + film - reduced platelets and RBC fragments
What do you do when INR is too high?
stop warfarin or reduce dose
give vitamin K1
give coagulation factors -berpilex
Describe coagulopathy in liver disease
poor coagulation factor synthesis vit K déficient poor clearance of activated coagulation factors DIC hypersplenism reduced thrombopoietin synthesis
Describe haemophilia A
factor VIII deficiency
x-linked inheritance
prolonged APTT
What is the treatment for coagulation factor deficiency?
education
desmopressin
replacement therapy - recombinant produced factor concentrate
gene therapy
Describe von willebrand disease
most common mild bleeding disorder
mostly autosomal dominant with incomplete penetrance
mucosal type bleeding pattern
reduced VWF +/- reduced platelet aggregation +/- reduced FVIII
Describe type I VWD
partial quantitive deficiency
Describe type II VWD
qualitative deficiency
Describe type 3 VWD
virtually complete deficiency
Describe severe inherited platelet disorders
rare
autosomal recessive
mucosal type bleeding patten
What is glansmanns thombasthenia?
absent/defective GP IIb/IIIa
normal platelet count
What is Bernard soupier syndrome?
absent/defective GP Ib/V/IX
macrothrombocytopaeia
How is bleeding treated in inherited platelet disorders?
pressure
tranexamic acid / desmopresin
platelet transfusion
rFVIIa
Describe inherited thrombophilia
deficiencies of natural anticoagulants antithrombin protein C protein S Factor V leiden - résistance to APC prothrombin gene mutation (increased prothrombin)
Describe lupus anticoagulant
phospholipid dependent antibody
interferes with phospholipid dependent tests
APTT prolonged
if persistent, may be associated with prothrombotic state
What is antiphospholipid syndrome?
persisting lupus anticoagulant and thrombosis or recurrent fetal loss
How do you test for lupus anticoagulant?
APTT - prolonged
APTT 50:50 dilution - only partially corrects
DRVVT ratio prolonged
corrects with excess phospholipid