Haematology Flashcards
what are the three components of blood?
red blood cells
plasma
clotting agents
what are the three principal functions of blood?
transport
fighting infection
promoting vascular integrity
what are the three general pathogenic mechanisms of haematological abnormalities?
- too many cells
- not enough cells
- abnormal function of cells
what aremain components of bone marrow?
haemopoietic stem cells
adipose tissue
which types of blood cells are classed as myeloid cells?
erythrocytes platelets neutrophils basophils eosinophils monocytes
which types of blood cells are classed as lymphoid cells?
B cells
T cells
NK cells
what are the three subtypes of T cells, and what is their function?
- cytotoxic T cells - kill pathogen
- helper T cells - help cytotoxic T cells kill pathogens and help antibody production
- regulatory T cells - dampen down immune response
what can reticulocytes be useful for?
useful for measuring bone marrow function (ie red cell production)
what is erythropoietin, where is it produced and why?
hormone that is produced by the kidneys in response to hypoxia, stimulates red blood cell production by bone marrow
what is the function of erythropoietin?
it stimulates haematopoietic stem cells in bone marrow to differentiate into erythrocytes
what are the stages of red blood cell differentiation?
haematopoietic stem cell –> myeloid progenitor cell -> erythroblast -> reticulocyte -> erythrocyte
how long does it take for reticulocytes to differentiate into erythrocytes?
~24 hours
what is the lifespan of an erythrocyte?
~120 days
what hormone regulates platelet production?
thrombopoietin
what is the lifespan of a platelet?
7 days
where is thrombopoietin produced?
in the liver
what is the lifespan of a neutrophil?
1-2 days
what stimulates neutrophil production?
granulocyte-colony stimulating factors
interleukins
macrophages
what are the stages of platelet differentiation?
haematopoietic stem cell -> myeloid progenitor cell -> megakaryocyte -> platelet
what are the stages of neutrophil differentiation?
haematopoietic stem cell -> myeloid progenitor cell -> neutrophil
what are monocytes?
macrophages that stay in the blood
what name is given to monocytes that have migrated to 1. liver, 2. kidneys, 3. skin, 4. brain?
- kuppfer cells
- mesangial cells
- langerhans cells
- microglia
what is main function of eosinophils?
fighting off parasite infections and mediating allergies
where do B and T cells mature?
B cells - bone marrow
T cells - thymus
what is the main role of B cells?
antibody production
immune memory
main action of antibodies?
opsonisation of pathogen
what is the role of IgG?
immune surveillance in circulation long after infection
what is the role of IgA?
immune surveillance of mucosa (gut, trachea)
what is the role of IgE?
mediation of allergies
what is the role of IgM?
first antibody to respond during an infection
what is positive and negative selection in terms of lymphocyte maturation?
positive selection - if cell doesn’t react to self-antigens it survives and is taken to periphery
negative selection - if cell reacts to self-antigens it is killed
what is the difference between Class I and Class II HLA?
Class I HLA - displays self-antigens on all own cells
Class II HLA - displays foreign antigens eaten by APC’s
what are paraproteins?
monoclonal antibodies in the blood which only arise from abnormal proliferation of mature B cells or plasma cells
what is the normal value range for Haemoglobin for men an women?
men: 135-170
women: 120-160
what is the normal value range for platelets in the blood?
150-400
what is the normal value range for WBC in the blood?
4-10
name the main diagnostic tools that are done in haematology
- FBC
- clotting factors/platelet clotting times
- chemical assays (haematinics)
- biopsies (bone marrow, lymph node)
- imaging (Xray, CT, MRI)
what are the three most common haematinics?
iron
folate
vitamin B12
what does a blood group depend on?
it depends on the antigens its red blood cells have on their surface
what antibodies does blood group A produce?
anti-B antibodies
what antibodies does blood group B produce?
anti-A antibodies
what antibodies does blood group O produce?
anti-A and anti-B antibodies
why can blood group O give blood to everyone but can only receive from other O?
because group O has no antigens, therefore group A and group B won’t trigger an immune response against it. however, group O produces anti-A and anti-B antibodies, therefore it can only receive from blood group O
what kind of antibody do blood groups present?
IgM
which antibodies can fix complement?
IgM
what are the most common blood groups?
A and O
who can blood group O donate to?
A, B, AB and O
what is the difference between giving someone red blood cells (RBC) and FFP (fresh frozen plasma)?
RBC is literally only a donation of red cells
FFP contains proteins, antibodies and clotting factors but no red cells
name a few indications of RBC transfusion
severe acute anaemia
bone marrow failure
prior to major surgery
to replace damaged RBC eg sickle cell
what is the storage temperature for blood?
4 degrees
what is the storage temperature for platelets?
22 degrees
what is the average transfusion time for blood?
2-4 hours
what is the average transfusion time for platelets?
20-30mins
what antibodies does AB produce?
no antibodies
who can an AB fresh frozen plasma donor give blood to, and why?
AB FFP donor can give to A, AB, B and O because their plasma contains no antibodies at all
why is RhD blood group important?
because if someone is RhD negative, they can get a transfusion reaction if they are transfused with RhD positive blood
what is apheresis?
the process of separating blood into individual components for transfusion
what is contained in the plasma once whole blood is separated?
clotting factors
albumin
antibodies
what is contained in the buffy coat layer once whole blood is separated?
white blood cells
platelets
name a few indications for platelet transfusion
massive haemorrhage
bone marrow failure
prior to surgery
cardiopulmonary bypass
what is the main aim of fresh frozen plasma transfusions?
to promote coagulation
what is the main aim of red cell transfusions?
to increase hemoglobin and oxygen levels
what is the main aim of platelet transfusions?
to correct low platelet levels
what are the processes in place when taking blood to the blood bank?
- EDTA tubes (x2)
- group and screen (blood type, antibodies)
- Coombs test
what is the process of the Coombs test in haematology?
it involves adding anti-human antibodies to a blood sample; if there are autoantibodies or complement stuck to the RBC, the anti-human antibodies will attach to these, causing the RBC to crosslink and agglutinate
what is the aim of the Coombs test?
it is used in haemolytic anaemia to identify whether the cause of the haemolysis is auto-immune or not
what is the difference between direct and indirect Coombs test?
Direct - identifies antibodies stuck to RBCs
Indirect - identifies free floating antibodies in plasma
when is a Coombs test positive for antibodies?
when the RBC agglutinate on the blood film
what is haemolytic disease of the newborn (HDN) and what causes it?
it is the destruction of baby’s red cells by mum’s antibodies, when baby has RhD positive blood and mum has RhD negative blood
for which pregnancy is haemolytic disease of the newborn normally a problem?
any pregnancy after the first one with a baby who has RhD positive blood
when is prophylactic anti-D given to pregnant women?
as routine during week 28
what is the aim of giving prophylactic anti-D to pregnant women?
it neutralises any RhD positive antigens that get into the circulation, so that mum doesn’t form any antibodies against them
in which areas of red blood cells can congenital anaemias occur?
- cell membrane
- enzymes
- haemoglobin
what happens to red blood cells in congenital anaemias like spherocytosis and elliptocytosis?
structural proteins that maintain the biconcave shape are mutated, causing the red cells to change shape
what are the structural proteins in red cell membranes that, when mutated, can cause congenital anaemias?
ankyrin
Band 3
spectrin (alpha and beta)
why are red cells normally biconcave?
because this allows them to squeeze through tight capillaries
what is the consequence of congenital anaemias affecting the cell membrane?
early haemolysis by the reticuloendothelial system
what system in the body is responsible for getting rid of old or faulty red blood cells?
the reticuloendothelial system
what are the main cellular processes which occur in red blood cells? what is the role of each?
glycolysis - energy
pentose phosphate pathway - protection against reactive oxygen species
mutation in which red blood cell enzymes can cause congenital anaemias?
- glucose 6 phosphate dehydrogenase (G6PD) deficiency
- pyruvate kinase deficiency
why is G6PD important in red cell metabolism?
it forms a link between glycolysis and the pentose phosphate pathway, and protects red cells from oxidation
what is the genetic inheritance of G6PD deficiency?
X linked
what triggers haemolytic anaemia in G6PD deficiency?
drugs
fava beans
infections
severe disease eg DKA
where does haemolysis occur in anaemia caused by G6PD deficiency?
intravascular haemolysis
name a few symptoms/signs of intravascular haemolysis
- anaemia
- pigment gallstones
- dark urine
- jaundice
- splenomegaly
- hepatomegaly
what is the pathology behind the signs of intravascular haemolysis?
red cells bursting in the circulation, causing haemoglobin to spill into the circulation and bilirubin levels in the blood increasing
what is the general treatment of haemolysis?
folic acid and iron replacement
blood transfusion
why is B12 not routinely given as replacement of anaemia, unless there is a specific B12 deficiency?
because normally B12 stores in the liver last for about 3 years
what are the main congenital haemoglobinopathies?
thalassaemia
sickle cell disease
what is thalassaemia?
loss or mutation of certain globin genes, causing a reduction in globin chains and lower haemoglobin levels
what is sickle cell disease?
structural abnormality in beta chains of haemoglobin, which cause the chains to crystallise and change the shape of the red cell
what is HbF, and what is it made up of?
HbF is fetal haemoglobin
2 alpha chains + 2 gamma chains
what is HbA2 and what is it made up of?
HbA2 is a type of haemoglobin that makes up 2% of our total haemoglobin
2 alpha chains + 2 delta chains
what is 97% of our haemoglobin made up of?
2 alpha chains + 2 beta chains
what is alpha thalassaemia?
it’s a congenital anaemia caused by absence in one or more alpha genes, causing a reduced number of alpha chains and therefore less haemoglobin
why is a lack of alpha globin chains incompatible with life?
because formation of haemoglobin depends on 2 alpha chains bound to two beta, delta or gamma chains
what is beta thalassaemia major?
it’s a congenital anaemia caused by absence of beta globin genes, resulting in loss of beta chains and therefore very low levels of haemoglobin
what does beta thalassaemia minor look like on a blood film?
microcytic and hypochromic red cells
what is sickle cell disease?
it’s a congenital anaemia caused by abnormal beta globin chains, which crystallise in low oxygen tension areas and cause the red cell to become sickle shaped
what are the main complications of sickle cell disease, as a result of the abnormal red cell shape?
early haemolysis
vaso-occlusion
why is sickle cell disease a risk factor for CVA?
because the sickle cell shaped red cells can cause vaso-occlusion
how does sickle cell disease cause anaemia?
because of the red cells are haemolysed due to their abnormal shape
why do people with sickle cell anaemia not have any problems with hypoxia?
because sickle red cells have slightly lower affinity for oxygen so give it up more readily
what is the appearance of G6PD deficient red blood cells?
bite cells
blister cells
how many alpha and beta genes do you get from mother and father?
alpha genes - two from mum, two from dad
beta genes - one from mum, one from dad
what is the genetic inheritance of thalassaemia?
autosomal recessive
what is the genetic inheritance of sickle cell anaemia?
autosomal recessive
what is the appearance of red blood cells in thalassaemia minor?
hypochronic microcytic
how is a sickle cell crisis managed?
supportive: analgesia, oxygen, fluids, antibiotics if needed
how does sickle cell anaemia affect the spleen?
it causes hyposplenism
as a result of vaso-occlusion in sickle cell anaemia, name a few clinical presentations that may occur
vaso-occlusion (CVA, bone pain, chest crisis, pain crisis)
sequestration (liver, spleen)
hyposplenism (increased infections)
chronic haemolytic anaemia (gallstones, dark urine, jaundice)
what is the long-term treatment for sickle cell disease?
vaccinations and prophylactic antibiotics
folic acid replacement
blood transfusions
hydroxycarbamide
what is the acute treatment for sickle cell disease presentations?
oxygen analgesia fluids antibiotics blood transfusion if severe
what’s an important complication in beta thalassaemia treatment, and how is it prevented?
iron overload
iron chelation therapy is started alongside transfusions to prevent iron overload
how does hydroxycarbamide reduce the amount of sickle cell acute attacks?
by increasing the production of fetal haemoglobin, which doesn’t sickle, and therefore reducing the number of sickle cells
in anaemia, what investigation is done to confirm the presence of haemolysis?
bilirubin and LDH levels
in anaemia, what investigation is done to assess bone marrow function?
reticulocyte count
in anaemia, what investigation is done to assess iron levels?
ferritin levels
in anaemia, what investigation is done to test for megaloblastic anaemia?
B12/folate levels
what haematinic replacement should anyone with haemolytic anaemia receive?
folic acid replacement
what is the presentation of beta thalassaemia major?
severe anaemia from 3 months of age bone deformities bone marrow expansion splenomegaly growth retardation
why does beta thalassaemia major cause bone deformities?
because the lack of haemoglobin causes bone marrow to expand in an effort to create red cells
what is the treatment for beta thalassaemia?
blood transfusion every 4-6 weeks
what are the hereditary anaemias caused by abnormalities in haem synthesis steps? name the steps affected
mitochondrial step abnormalities - sideroblastic anaemias
cytoplasmic step abnormalities - porphyrias
what is the genetic inheritance of G6PD deficiency?
X-linked
what type of haemolysis is caused by a trigger in G6PD deficiency anaemia?
intravascular haemolysis
what are the generic features of anaemia?
pallor tiredness swollen ankles breathlessness/dizzyness gallstones chest pain
why do men have higher haemoglobin levels than women?
because hormones affect Hb production, and testosterone in men causes an increase in Hb production
how does age affect Hb levels?
babies are polycythaemic, whereas old people tend to have low Hb
why is acute anaemia more likely to cause hypoxic symptoms than chronic anaemia?
because chronic anaemia allow the body to adapt to lower levels of Hb
what are the morphological features of red blood cells that can help identify the type of acquired anaemia?
MCV - mean cell volume (size)
MCH - mean cell haemoglobin (colour)
what are the 3 possible morphological features of acquired anaemia?
- hypochromic microcytic
- normochromic normocytic
- macrocytic
what is the commonest cause of anaemia?
iron deficiency
what diagnostic test should be done if a blood film shows hypochromic microcytic anaemia?
serum ferritin levels
in hypochromic microcytic anaemia, what diagnosis do high/normal levels vs low levels of serum ferritin indicate?
low levels - iron deficiency
high/normal levels: thalassaemia trait, secondary anaemia
what is the pathology behind secondary anaemia?
increased hepcidin levels - ferroportin blocked, not allowing iron to be transported into cells and therefore reducing ability to make red blood cells
in iron metabolism, define the role of ferritin, transferrin, ferroportin and hepcidin
ferritin - molecule used to store iron
transferrin - protein used to carry iron in the circulation
ferroportin - endothelial channel that allows iron to enter and exit cells
hepcidin - molecule that regulates iron absorption by opening/blocking ferroportin according to iron levels
which blood cancer is characterised by proliferation of undifferentiated myeloid progenitor cells?
acute myeloid leukaemia
in AML, are the proliferating cells differentiated?
no
how does AML affect the bone marrow?
it causes bone marrow failure, due to the overwhelming amount of undifferentiated blasts taking over the bone marrow
what percentage of cells on the blood film have to be undifferentiated blasts, for it to be classed as AML?
> 20% of cells on blood film have to be undifferentiated blasts
what are the three classic features of bone marrow failure? think about the cells involved
anaemia (due to low red cells)
thrombocytopaenia (due to low platelets)
neutropaenia (due to low neutrophils)
what symptoms can occur in bone marrow failure, as a result of the pancytopaenia?
anaemia - pale, tiredness, fatigue, SoB
thrombocytopaenia - purpura, mucosal bleeding, ecchymosis
neutropaenia - increased risk of infections
what is pancytopaenia?
reduction in all blood cell numbers
what investigations are essential in diagnosing myeloid malignancies?
- full blood count
- blood film
- bone marrow aspirate
- cytogenetics/immunohistochemistry
what is the treatment of AML?
- chemotherapy
- supportive treatment (prophylaxis for infections)
- stem cell transplantation
why is AML more severe than CML?
- AML develops more rapidly
- AML causes bone marrow failure as a result of blast proliferation
- blasts in AML do not function at all, whereas the proliferating myeloid cells in CML still function to a degree
which population is more at risk of developing AML?
older population
in which type of myeloid malignancy is there proliferation of differentiated myeloid cells?
chronic myeloid leukaemia
what is the pathophysiology of CML?
uncontrolled proliferation caused by abnormal tyrosine kinase protein (BCR-ABL) as a result of a translocation between chromosomes 9 and 22 forming the Philadelphia Chromosome
what is the treatment of CML?
- tyrosine kinase inhibitors (imatinib = Glivec)
- stem cell transplantation (if TKI fail)
what is an important complication in AML chemotherapy treatment?
severe bleeding in brain and lungs
why is there need for supportive treatment during AML chemotherapy treatment?
because chemotherapy completely stops bone marrow function for several weeks, leaving patients severely immunocompromised
in which malignancy is the Philadelphia Chromosome found, and what is it formed by?
CML
formed by translocation between chromosomes 9 and 22
name some features of CML
high WBC and platelet count
anaemia
significant splenomegaly
gout
why is stem cell transplantation essential after chemotherapy in AML?
because it maintains remission of disease
what is the myeloproliferative disease which affects red cells?
polycytaemia vera
what is the pathophysiology of myeloproliferative diseases?
constant activation of JAK receptors causing proliferation of certain myeloid cells
which myeloid cells are increased in polycytaemia vera?
mainly red cells, but also white cells and platelets
which myeloid cells are increased in essential thrombocytaemia?
mainly platelets
what is the treatment of polycytaemia vera, and what is its aim?
venesection, aspirin, hydroxycarbamide, JAK inhibitors
aim to reduce haematocrit to <45% and reduce risk of CVA resulting from thrombosis
what are some symptoms of polycytaemia vera?
itching
headaches
thrombosis - MI, stroke etc
what is the treatment of essential thrombocytaemia, and what is its aim?
aspirin, hydroxycarbamide, JAK inhibitors
aim to block platelet action and reduce risk of CVA/thrombosis
what is a significant risk when a patient develops a myeloproliferative disease?
it can develop into AML further down the line
blood cancers make up what percentage of total cancers?
about 10%
which type of leukaemia are children more likely to develop?
acute lymphoblastic leukaemia
which blood cancers involve proliferation of undifferentiated cells?
acute myeloid leukaemia
acute lymphoblastic leukaemia
which blood cancers involve proliferation of differentiated myeloid cells?
chronic myeloid leukaemia
polycytaemia vera
essential thrombocytaemia
which blood cancers are also called myeloproliferative neoplasms?
polycytaemia vera
essential thrombocytaemia
which blood cancers involve proliferation of differentiated lymphoid cells?
chronic lymphocytic leukaemia
Hodgkin’s lymphoma
Non-Hodgkin’s lymphoma
what differentiates Hodgkin’s from Non-Hodgkin’s lymphoma?
- Hodgkin’s Lymphoma mainly affects lymph nodes around the head and respiratory tract, without much extra-nodal involvement
- Non-Hodgkin’s Lymphoma affects symmetrical lymph nodes all over the body and has more frequent extra-nodal involvement
where do lymphomas normally arise?
in the germinal center of a lymph node
which lymphoid cell type is most commonly affected in lymphomas? why is that?
B cell most commonly affected, because they proliferate at very high rates to make memory and plasma cells, increasing the risk of an accidental mutation in the process
during which process in B cell maturation do lymphomas commonly arise?
during somatic hypermutation (extensive proliferation to make plasma and memory cells)
when is a swollen, localised lymph node more likely to be an infection or a tumour?
if localised and painful - more commonly an infection
if localised and painless - more commonly cancer metastasis
when do swollen, painless lymph nodes point towards lymphoma rather than metastatic cancer? explain why
when the swollen lymph nodes are generalised - lymphomas spread through lymphatic system, whereas metastases spread through circulation so are unlikely to present in multiple lymph nodes
what causes secondary anaemia to develop?
increased levels of hepcidin (eg due to inflammation/infection) cause a decrease in iron passing through ferroportin and into cells
name a few common causes of iron deficiency anaemia
lack of iron in diet malabsorption GI bleed menorrhagia increased requirement (pregnancy)
what do red cells look like in iron deficiency anaemia?
hypochromic and microcytic
what feature of anaemia can be seen in nails?
koilonychia
what features of anaemia can be present in the mouth?
atrophic, painful tongue
angular stomatitis
what is the first line treatment of iron deficiency?
oral iron replacement tablets
what investigation is done when a blood film shows normochromic, normocytic anaemia?
reticulocyte count
what does a low reticulocyte count mean in normochromic, normocytic anaemia?
it means bone marrow can’t produce new reticulocytes because there is a lack of available iron ie secondary anaemia
what does a high reticulocyte count mean in normochromic, normocytic anaemia?
it means the bone marrow is working hard to replace red cells ie haemorrhage or acute haemolysis
in secondary anaemia, is serum ferritin high or low? explain why
high, because underlying condition is causing an increase in hepcidin which stops ferritin from being absorbed, but it also increases ferritin levels
ferritin is an acute phase reactant. what does that mean?
it means that during infection or inflammation the ferritin levels in the circulation go up
what is haemolytic anaemia?
it’s premature destruction/removal of red blood cells from the circulation
what are the two possible mechanisms haemolytic anaemia can be acquired? where does each one occur in relation to the circulation?
- autoimmune - occurs extravascularly
- non-autoimmune - occurs intravascularly
what red cell abnormalities might cause congenital haemolytic anaemia?
- abnormal red cell shape (spherocytosis)
- abnormal haemoglobin (sickle cell anaemia, thalassaemia)
- abnormal enzymes (G6PD deficiency)
what organ can be noticeably affected in autoimmune haemolytic anaemia? how and why?
the spleen can become very enlarged, because it is working harder than usual to remove the red blood cells it sees as foreign
what investigation is done to identify whether haemolytic anaemia is autoimmune or not?
Coombs test (ie antiglobulin testing)
if a Coombs test result shows agglutinated red blood cells, what does that mean?
it means the haemolytic anaemia is autoimmune
if a Coombs test result shows non-agglutinated red blood cells, what does that mean?
it means the haemolytic anaemia is not caused by an autoimmune response
what is an important consideration when interpreting the results of a Coombs test in haematology?
some antibodies only activate in warm conditions, and some only in cold conditions. this can point to different causes for immune haemolytic anaemia
what blood tests are done to identify whether a patient with anaemia is haemolysing?
- FBC
- reticulocyte count
- bilirubin/LDH
- haptoglobin
- Coombs test
what are the management options of haemolytic anaemia?
- folic acid replacement
- treating underlying cause
- immunosuppression
- transfusion
- splenectomy
what is macrocytic anaemia also called?
megaloblastic anaemia
what is macrocytic/megaloblastic anaemia caused by?
mainly vitamin B12 or folic acid deficiency
also: myelodysplasia, drugs, liver disease, alcohol, hypothyroidism
how is vitamin B12 deficiency managed?
intramuscular B12 injections (every 3 months)
what causes vitamin B12 deficiency?
- pernicious anaemia
- gastrectomy
what causes folate deficiency?
- diet
- increased requirement
- malabsorption
what are the main features of B12/folate deficiency?
anaemia symptoms (pale, fatigue, SoB, jaundice) neurological symptoms (peripheral neuropathy)
what does megaloblastic anaemia look like on a blood film?
- red cells look large and flabby, more friable and prone to haemolysis
- neutrophils look hypersegmented
in anaemia, what specific blood tests help point towards the presence of haemolysis?
bilirubin levels
lactate dehydrogenase levels
haptoglobin levels
how is folate deficiency managed?
oral folate replacement
other than anaemia, what can vitamin B12/folate deficiency present with?
peripheral neuropathy
what are B symptoms in lymphoma?
weight loss night sweats fever pruritis fatigue
what is the commonest physical presentation of lymphoma?
lymphadenopathy
what is the first line investigation for lymphoma?
biopsy of lymph node/bone marrow
which type of leukaemia is the commonest in children?
Acute lymphoblastic leukaemia
what is the commonest type of lymphoma? how aggressive is it?
diffuse large B cell lymphoma - high grade
what is the commonest low-grade lymphoma?
follicular lymphoma
which blood cancer involves proliferation of undifferentiated lymphoid cells?
acute lymphoblastic leukaemia
how can children with ALL present?
bone marrow failure
bone pain
limp
which lymphoid progenitors are often involved in ALL?
- B cell progenitors
how is the type of lymphocyte progenitor identified in ALL?
through immunophenotyping - if it expresses CD19 it’s a B-lymphoblast
what is the management of ALL?
chemotherapy
CNS therapy
stem cell transplant
immunotherapy - RiTe, CAR
why is there need for CNS specific therapy in ALL, and how is it administered?
- because chemotherapy drugs normally don’t penetrate BBB, and lymphoblasts often hide in the brain
- intrathecal methotrexate injection
what is the commonest type of leukaemia?
chronic lymphocytic leukaemia
what is the gender distribution of CLL?
2:1 males to females
exposure to what virus has been associated with CLL development?
EBV virus
how does CLL often present?
often asymptomatic presentation
what is immune paresis?
loss of immunoglobulin production
what type of blood cancer is immune paresis associated with?
CLL
what is the staging score used for CLL?
Binet staging
what are the three stages of CLL according to the Binet score?
A - less than 3 lymph nodes involved
B - more than 3 lymph nodes involved
C - 3 or more lymph nodes + cytopaenia
name a few indications to treat CLL
bone marrow failure lymphadenopathy splenomegaly systemic symptoms rapid lymphocyte proliferation
if there are no severe symptoms, what is the management of CLL?
watch and wait
frequent monitoring
what is the management of CLL?
chemotherapy
monoclonal antibodies
what are some possible signs/symptoms of lymphoma?
lymphadenopathy
B symptoms
hepatosplenomegaly
what are the main diagnostic investigations for lymphoma?
lymph node biopsy
bone marrow biopsy
CT scan
what lymphocytic lineage is normally presented by non-Hodgkin lymphoma?
B cell lineage
why are low grade lymphomas incurable?
because they are very slow growing, so it is difficult to target actively proliferating cells
what is the management of low grade lymphoma?
watch and wait
what is the therapeutic management of non-Hodgkin lymphoma?
chemotherapy + monoclonal antibody (anti-CD20)
what are the commonest age groups to get Hodgkin lymphoma?
20-30s
over 60
which subgroup of Hodgkin lymphoma patients are more likely to have had EBV exposure?
those patients who get Hodgkin lymphoma later in life
what is the presentation of lymphadenopathy in Hodgkin’s lymphoma?
symmetrical lymphadenopathy in upper respiratory tract and head, with little extranodal involvement
what is the presentation of lymphadenopathy in non-Hodgkin lymphoma?
lymphadenopathy not symmetrical, can present anywhere, 60% with extranodal involvement
what is he treatment of Hodgkin’s lymphoma?
chemotherapy
radiotherapy
monoclonal antibodies (anti-CD30)
with regards to monoclonal antibody treatment, which cell marker is targeted in non-Hodgkin lymphoma and Hodgkin lymphoma respectively?
non-Hodgkin - CD20
Hodgkin - CD30
what is the scoring system for lymphoma called, and what are the four stages?
Ann Arbor staging score:
1 - one lymph node
2 - two lymph nodes on same side of diaphragm
3 - disseminated lymph nodes on both sides of diaphragm
4 - extranodal disease
+ A (no systemic symptoms) or B (B symptoms)
what pattern of bleeding is found in platelet disorders?
mucosal bleeding:
ecchymosis, epistaxis, purpura, petechiae, menorrhagia
what pattern of bleeding is found in coagulation factor disorders?
muscle hematoma
haemarthrosis
CNS bleeding
what is haemophilia type A?
loss of coagulation factor VIII
what is haemophilia type B?
loss of coagulation factor IX
what is the mode of inheritance of haemophilia A and B?
X-linked
how can haemophilia affect the joints in the long run, if uncontrolled?
it can increase risk of osteoarthritis and haemophilic arthropathy
what is the management of haemophilia?
- recombinant factor 8/9 replacement
- desmopressin
- tranexamic acid
- prophylaxis in severe cases
- gene therapy
which bleeding disorders is desmopressin useful in?
Type 1 von Willebrand disease
Haemophilia A
what are the three subtypes of von Willebrand disease?
Type 1 - quantitative, not enough vWF
Type 2 - abnormal function of vWF
Type 3 - complete lack of vWF
what is the genetic inheritance of von Willebrand disease?
autosomal dominant
is von Willebrand disease inherited or acquired?
inherited
how does desmopressin work in bleeding disorders?
- it releases vWF from the endothelial cells
- it stabilises factor 8
which coagulation factors are only involved in the extrinsic pathway?
tissue factor
factor VII
factor V
which coagulation factors are only involved in the extrinsic pathway?
factor XII
factor XI
factor IX
factor VIII
does von Willebrand disease cause platelet deficiency type bleeding or coagulation factor deficiency type bleeding?
platelet deficiency type bleeding - mucosal, ecchymosis, epistaxis, menorrhagia
how common is von Willebrand disease?
common - 1 in 200
which type of haemophilia is more common?
Haemophilia A
what investigations are done to diagnose haemophilia, and what might they show?
platelet count - normal
prothrombin time (PT) - normal
partial thromboplastic time (APTT) - high
clotting factors - factor 8 or 9 low
what do PT and APTT test respectively in haematology?
PT - tests extrinsic and common coagulation pathway
APTT - tests intrinsic and common coagulation pathway
which clotting factors are vitamin K dependent?
factors 2, 7, 9 and 10
name a few causes of acquired bleeding disorders
- liver failure
- renal failure
- autoimmunity to clotting agents
- vitamin K deficiency
- diffuse intravascular coagulation
- drugs (warfarin, DOACs, aspirin)
what are the management options for von Willebrand disease?
- vWF concentrate
- desmopressin
- tranexamic acid
- menorrhagia management
what is the mechanism of action of tranexamic acid?
tranexamic acid blocks the conversion from plasminogen to plasmin, therefore stopping fibrin degradation
why does liver failure lead to bleeding disorders?
liver failure affects the liver’s production of clotting factors
why does disseminated intravascular failure lead to bleeding disorders?
because extensive coagulation uses up all available clotting factors, eventually leading to uncontrolled bleeding
what is autoimmune thrombocytopaenic purpura?
thrombocytopaenia (low platelet count) as a result of autoimmune reaction against own platelets
how is immune thrombocytopaenia treated?
steroids
IV immunoglobulin
splenectomy if hypersplenism
thrombopoietin analogues
define primary haemostasis and secondary haemostasis
primary haemostasis - initial platelet activity and start of fibrin plug formation
secondary haemostasis - coagulation cascade and stabilisation of solid fibrin plug
which molecules drive the degradation of fibrin in haemostasis?
t-PA: it converts plasminogen into plasmin, and plasmin breaks down fibrin plug
where is t-PA released from in haemostasis?
t-PA is released from endothelial cells
what is t-PA?
tissue plasminogen activator - converts plasminogen into plasmin, which breaks down fibrin plug
what diagnostic molecule is found in the circulation as a result of fibrin degradation?
d-dimer
what other conditions is immune thrombocytopaenic purpura associated with?
infections (EBV, HIV)
lymphoma
drug related
why is Vitamin K injected in babies right after birth?
to give their coagulation system a boost and prevent Haemorrhagic Disease of the Newborn
when is a diagnosis of haemophilia first made?
in children between 6months and 2 years of age
what defines haemophilia as mild, moderate or severe?
residual coagulation activity:
mild is 5-30%
moderate is 1-5%
severe is <1%
what is the monoclonal antibody that can now be used for haemophilia A treatment, and what is its mechanism of action?
Emicizubab (Hemlibra)
it replaces factor VIII and binds factor X to factor IXa in order to activate factor X and trigger common coagulation cascade
name a few complications of haemophilia treatment
- viral infections (HIV, HBV, HCV)
- inhibitors (anti-factor 8 antibodies)
- MI (desmopressin promotes platelet adherence)
why does liver failure show prolonged PT and aPTT time on coagulation tests?
because the liver produces all coagulation factors, so a lack in production causes deficiency in both extrinsic and intrinsic coagulation pathway
which coagulation factors are only involved in the common pathway?
factor X factor II (prothrombin) factor I (fibrinogen)
vitamin K dependent coagulation factor deficiency is associated with which GI condition and why?
cholestasis/biliary tree disease, because it leads to an inability to absorb fat from diet which is essential for factor II, VII, IX and X production
what’s the purpose of heparans, thrombomodulin and TFPI in a healthy blood vessel?
they inhibit the adhesion of platelets to the endothelial wall
what is the physiological activator that triggers platelet adhesion in a damaged blood vessel?
tissue factor
which platelet surface glycoprotein binds fibrinogen?
GP 2b/3a
which platelet surface glycoprotein binds to collagen exposed by blood vessel damage?
GP Ia/2a
what are the most important cell surface receptors on a platelet?
ADP receptor
epinephrine receptor
thrombin receptor
what are the two granules inside a platelet called, and what does each release?
alpha granule - vWF, thrombin
dense granule - calcium, serotonin, ADP/ATP
what is von Willebrand Factor released by?
platelets and endothelial cells
which platelet surface glycoprotein binds to von Willebrand Factor?
GP 1b
what are the three main actions of platelets?
adhere
activate
aggregate
how do platelets adhere to damaged blood vessels?
they adhere to collagen through GP Ia and to von Willebrand Factor through GP 1b
how do platelets activate?
they activate through ADP and epinephrine attaching to their receptors, causing arachidonic acid to be converted into thromboxane A2 through COX-1
how do platelets aggregate?
they aggregate through the action of thromboxane A2, which allows them to shrink and stick together
how do platelets facilitate coagulation?
platelets help the coagulation process by flipping their phospholipid membrane over
what enzyme helps the phospholipid membrane of platelets flip inside out to help coagulation?
scramblase
what are the three main natural anticoagulants?
- tissue factor pathway inhibitor (TFPI)
- activated protein S and protein C
- antithrombin
which coagulation factors are switched off by TFPI?
factor VIIa and factor Xa
which coagulation factors are switched off by activated protein S and C?
factor Va and factor VIIIa
which coagulation factors are switched off by antithrombin?
mainly factor Xa and thrombin, but also factor XIa, IXa and VIIIa
what is the purpose of natural anticoagulants in haemostasis?
they ensure the fibrin clot is confined to the area of damage
how does aspirin inhibit platelet action?
it inhibits platelet aggregation by blocking COX-1 pathway, preventing the conversion of arachidonic acid to thromboxane A2
how do clopidogrel and ticagrelor inhibit platelet action?
they inhibit platelet activation by blocking the ADP/epinephrine receptors and stopping the P2Y12 pathway
how do abciximab and tirofiban inhibit platelet action?
it they stop fibrinogen binding to GP 2b/3a
how does warfarin stop coagulation?
it blocks factors 2, 7, 9 and 10
how can the effects of warfarin be reversed?
by injecting vitamin K
how does heparin stop coagulation? which natural anticoagulant does it mimic?
it blocks factor Xa and thrombin, mimicking antithrombin
how do NOACs like apixaban and rivaroxaban stop coagulation?
they stop factor X from being activated, by sitting on the serine site where the inactive zymogen is normally cleaved to activate it
what is the serine site on coagulation factors?
it’s the area on the protein that is cleaved in order to activate the factor
how does dabigatran stop coagulation?
it acts as a direct thrombin inhibitor, by binding to its active site
what are arterial thrombi mainly made of, and what colour are they?
white thrombi containing mostly platelets (and some fibrin)
what are venous thrombi mainly made of, and what colour are they?
red thrombi containing mostly fibrin (and some red cells)
which elements of Virchow’s triad are most likely to lead to venous thrombosis?
hypercoagulability ie cancer, pregnancy, OCP
stasis ie long haul flights, immobility
which element of Virchow’s triad is most likely to lead to arterial thrombosis?
vessel damage - ie atherosclerosis
what are the two commonly used pre-test probability scores for DVT?
Wells score
Geneva score
when is a D-dimer test done for DVT?
when the pre-test probability score is low
what is the main aim of a D-dimer test for DVT?
to rule out the diagnosis of DVT
when testing compressibility of a vein, when is it more or less likely to be a DVT?
if vein compressible - probably not DVT
if vein non-compressible - probably DVT
what imaging tests are carried out for DVT and PE?
DVT - doppler USS
PE - V/Q scan
which types of long-term conditions can predispose to DVT?
cancer
myeloproliferative neoplasms
autoimmune conditions
which class of drug is given to patients following a DVT/PE?
anticoagulants
what is Factor V Leiden?
it’s a mutation in factor 5, which makes it resistant to being switched off by activated protein S and C
what is the genetic inheritance of Factor V Leiden?
autosomal dominant
what are microvascular thrombi seen in DIC made up of?
can be either platelets, fibrin or both
name some risk factors for arterial thrombosis
hypertension smoking obesity diet sedentary lifestyle diabetes high cholesterol age
name some risk factors for venous thrombosis
immobility pregnancy long haul flights older age obesity HRT/OCP surgery systemic disease (eg cancer, autoimmune disease) family history inherited conditions (factor V leiden, antithrombin deficiency)
what is the iron level in the blood in polycythaemia vera?
almost always low
what is the pathogenesis of myelofibrosis?
proliferation of abnormal megakaryocytes, leading to fibrosis in bone marrow
what is a characteristic sign of myelofibrosis on a blood film?
tear-drop shaped red cells
nucleated red cells
large platelets
blast cells
name a few signs that point to a diagnosis of myelofibrosis
very enlarged spleen
tear-drop shaped red cells on blood film
fibrosis in bone marrow biopsy
how can chronic leukaemia and myeloma affect red blood cell count?
they can cause anaemia due to autoimmune haemolysis
which monoclonal antibody is used to target CD20 B cells in lymphoma?
rituximab
what chemotherapy drug is used for low grade lymphomas?
bendamustine
what treatment regimen is used for high grade lymphoma?
R-CHOP
- rituximab
- cyclophosphamide
- hydroxydoxorubicin
- vincristine
- prednisolone
what is the difference between CD19 and CD20 B cells?
CD19 is found on all B cells, regardless of their maturity
CD20 is only found on mature B cells
what cell marker is expressed on T cells in CLL?
CD5
which portion of an antibody defines the class of antibody?
the heavy chain - Fc portion
which immunoglobulin has the highest molecular weight and why?
IgM - because it’s a pentamer
what are the two possible structures of a light chain in antibody production?
kappa
lambda
what is the most prevalent class of immunoglobulin?
IgG
what is the first line investigation for the diagnosis of myeloma? what does it identify?
serum protein electrophoresis - identifies presence of paraproteins in the blood
name a few examples of lab tests that can be done to help diagnose myeloma
- total immunoglobulin levels
- serum protein electrophoresis
- immunofixation
- light chains levels (kappa vs lambda)
proliferation of B lymphocytes leads to which type of blood cancer?
lymphoma
proliferation of plasma cells leads to which type of blood cancer?
myeloma
which immunoglobulin is released in lymphoma?
IgM
which immunoglobulin is released in myeloma?
IgG, IgA
do plasma cells release IgM?
no
which immunoglobulins do B cells and plasma cells produce respectively?
B cells - IgM
plasma cells - IgG, IgA
what is myeloma?
it’s a blood cancer resulting in abnormal proliferation of plasma cells and build up of paraprotein
what are the classic symptoms of myeloma?
CRAB:
- high calcium
- renal failure
- anaemia
- bone lesions
what is a rise in paraproteins in the blood called, if there are no symptoms indicating myeloma?
monoclonal gammopathy of uncertain significance (MGUS)
name some complications of paraprotein build up in myeloma
- renal disease
- hyperviscosity
- hypogammaglobulinaemia (low antibodies)
- amyloidosis
- increased risk of infections
if there is an abnormal build up of IgM in the blood, what is not the diagnosis and why?
it’s not myeloma, as plasma cells do not produce IgM
what are the management options for myeloma?
- chemotherapy
- immunotherapy
- steroids
- bisphosphonates
- stem cell transplant
on bone marrow biopsy, what percentage of total cell count needs to be plasma cells for myeloma to be confirmed?
more than 10%
what type of amyloidosis is caused by multiple myeloma?
AL amyloidosis - primary amyloidosis caused by misfolding of immunoglobulin light chains
what protein found in the urine can help diagnose multiple myeloma? what is this protein?
Bence-Jones protein
it’s a light chain (kappa or lambda) that has spilled out of the circulation and into the urine