haematology Flashcards
what are the two types of haemachromatosis
Primary Haemochromatosis
→ hereditary, most common form
Autosomal recessive inheritance
Mutations on the HFE gene
Secondary Haemochromatosis
→ caused by iron overload
Commonly transfusion related
which gene causes primary haemachromatosis and what is the inheritance pattern
HFE gene
Autosomal recessive
symptoms of haemachromatosis
fatigue
arthralgia
erectile dysfunction
grey/bronze pigmentation
polyuria / polydipsia
cirrhosis / hepatomegaly
what is the most useful marker for haemachromatosis
serum transferrin saturation >45%
what is the first test to become abnormal in haemachromatosis
serum transferrin saturation >45%
describe the iron study results for haemachromatosis
high serum iron
high serum ferritin
low TIBC
serum transferrin saturation >45%
management of haemachromatosis
1st line: therapeutic phlebotomy
2nd line: drug induced iron chelation - Deferoxamine
what globins make up HbF
2 alpha globin + 2 gamma globin
what globins make up HbA
2 alpha globin + 2 beta globin
what globins make up HbA2
2 alpha globin + 2 delta globin
what is the inheritance pattern of all haemaglobinopathies (sickle cell, thalassemia)
autosomal recessive
contrast alpha and beta thalassemia in terms of common pt population, number of alleles, and electrophoresis results
beta
- mediterranean descent
- 2 alleles
- no HbA, raised HbA2 and HbF
- no HbH
(look for raised HbA2 in Hb electrophoresis)
alpha
- asian and African descent
- 4 alleles
- present HbH
(look for HbH band in Hb electrophoresis)
what are the 2 forms of beta thalassemia and their symptoms
1 defective allele: Beta thalassemia minor
→ mild microcytic hypochromic anaemia.
Asymptomatic
2 defective alleles: Beta thalassemia major
→ severe haemolytic anaemia,
hepatosplenomegaly,
skeletal deformities
what are the 4 forms of alpha thalassemia and their symptoms
1 defective allele: Silent Carrier
→ asymptomatic.
No anaemia.
2 defective alleles: Αlpha Thalassaemia Trait
→ microcytic hypochromic red cells.
No anaemia.
3 defective alleles: Haemoglobin H (HbH) Disease
→ microcytic hypochromic anaemia with splenomegaly
4 defective alleles: Haemoglobin Bart Disease
→ intrauterine death
management of thalassemia major
lifelong blood transfusion therapy
(this may lead to iron overload so also give iron chelation therapy - Desferrioxamine)
genetic screening
individuals with an absent or dysfunctional spleen are at increased risk of severe infection esp caused by which bacteria?
the encapsulated bacteria - NHS
N. meningitidis
H. influenzae type b (Hib)
S. pneumoniae (pneumococcus)
what is seen on a blood film in hyposplenism / after splenectomy
howell-jolly bodies,
target cells,
pappenheimer bodies (siderocytes)
what do Howell jolly bodies indicate
splenic dysfunction
why is prophylactic aspirin usually indicted after a splenectomy
pt will have very high platelet count - thrombocytosis
(spleen is the primary site of destruction of platelets)
management of hypospelnism or splenectomy
prophylactic aspirin if they have thrombocytosis
Immunisations
→ vaccinations against
N. meningitidis,
H. influenzae type b and influenza virus
S. pneumoniae,
○ Pneumococcal vaccine 2 weeks before elective splenectomy
○ Annual influenza vaccination and Pneumococcal vaccine every 5 years
Prophylactic Antibiotics (Penicillin or Amoxicillin)
→ recommended in patients at high risk of pneumococcal infections
causes of DIC
STOP MT
⇒ sepsis/snakebites,
trauma,
osbtetric conditions,
pancreatitis,
malignancy,
Transfusion
acute vs chronic DIC
acute
- caused by trauma, sepsis and blood transfusions
- causes bleeding issues (petechiae, purpura, ecchymoses, epistaxis)
chronic
- caused by malignancy
- causes clotting issues (signs of DVT or arterial thrombosis)
significant FBC results in DIC
low platelets,
low haemoglobin
clotting results in DIC
low fibrinogen,
high D-dimer (fibrinogen degradation products),
prolonged PT + APTT
what is seen on blood film in DIC
schistocytes (fragmented RBC)
management of DIC
Platelet + Coagulation Factors Transfusion
○ Fresh Frozen Plasma
→ contains clotting factors (AB = universal donor)
○ Cryoprecipitate
→ replaces fibrinogen
Anticoagulation
→ Heparin
inheritance pattern of sickle cell
autosomal recessive
describe the mutation in sickle cell
mutation on 6th amino acid of beta chain of haemoglobin
polar glutamic acid is replaced by non polar valine
at what age does sickle cell present and why
6 months
HbF decreases and HbS increases
what disease does sickle cell have a protective factor against
malaria
what is the haemaglobin in sickle cell trait vs disease
HbAS - trait
HbSS - disease
describe the 4 dangerous events in sickle cell
vaso-occlusive crisis
- blood vessels blocked by sickle cells causing infarction
ACS (acute chest syndrome)
- pulmonary infiltrates causing dysnpea, wheeze, cough, temp, pain
sequestration crisis (splenic sequestration)
- sickled RBCs sequester in spleen and undergo phagocytosis –> functional hyposplenism –> reduced immune function (esp to encapsulated organisms - NHS)
- HIGH RETICULOCYTES + SPLENOMEGALY
Aplastic crisis
- parvovirus B19 stops erythropoiesis
- LOW RETICULOCYTES + SUDDEN ANAEMIA (drop in Hb)
list some symptoms of sickle cell
vaso-occlusive crisis
dactylitis
bone pain
high temp
Acute chest syndrome
lethargy + anaemia symptoms
splenic sequestration / splenomegaly
what is sickling in sickle cell disease precipitated by
infection
dehydration
hypoxia
acidosis
stress
cold
fatigue
gold standard Ix for sickle cell and results
Hb electrophoresis
- no HbA
- ^ HbF
- present HbS
what does blood film show in sickle cell
sickle cells
Howell jolly bodies
target cells
how does reticulocyte level differ in sequestration crisis vs aplastic crisis
splenic sequestration = high reticulocytes
(as RBCs are being phagocytoses in spleen, so new ones are made more rapidly)
aplastic crisis = low reticulocytes
(as parvovirus B19 stops erythropoiesis)
management of vase-occlusive crisis
strong analgesia
oxygen
fluids
transfusion
abx if infected
tx for chronic sickle cell disease
hydroxyurea (increases HbF which decreased frequency and duration of crisis)
regular transfusion
vaccinations
which mutation is associated with myeloproliferative disorders eg myelofibrosis, polycythaemia vera, thrombocythaemia
JAK2 mutation
describe mechanism of essential thrombocytosis (aka primary thrombocythaemia)
dysregulation of megakaryocyte proliferation
–> increase in circulating platelets
–> thrombocytosis
describe the mechanism of meylofibrosis
fibrosis of bone marrow
–> bone marrow failure
–> myeloproliferation in the spleen (to compensate for bone marrow not making any cells)
–> splenomegaly
which 2 myeloprolifertaive disorders cause massive splenomegaly
myelofibrosis
CML
what is dry tap and what condition is it seen in
failure of bone marrow aspirate
myelofibrosis
what is seen on blood film in myelofibrosis
tear drop poikilocytes (dactrocytes)
–> flat, elongated RBCs
what is erythromelalgia and which conditions is it seen in
warm, red, painful extremities (esp legs/feet)
worse in heat, better in cold
meyloprolifertaive disorders, some autoimmune diseases (eg lupus, MS)
what is the platelet count in myeloproliferative disorders
≥450 x 10⁹/L
which medication can be used to reduce platelet count in myeloroliferative disorders
hydroxycarbamide
(and use aspirin to precent thrombosis)
what is the inheritance pattern if haemophilia
X linked recessive
(so only in males)
what stage of haemostasis is affected in haemophilia
secondary haemostasis - as haemophilia causes a deficiency of coagulation factor
which factors are deficient in haemophilia A vs B
A –> 8
B —> 9
is haemophilia A vs B more common
A
how do you classify haemophilia severity according to haematoma formation
mild - haematoma formation after severe trauma
moderate - haematoma formation after mild trauma
severe - spontaneous haematoma formation
what is the hallmark sign/symptom of haemophilia
MSK bleeding
(pain/swelling/erythema/warmth.reduced rang of motion)
describe the investigations needed for haemophilia
test homeostasis pathways: prolonged APPT, normal PT
do a plasma factor 8 and 9 assay to confirm diagnosis
can also d a mixing study
what is the resist of a mixing study in haemophilia
correction of APTT with the mixing study suggests a coagulation factor deficiency and hence haemophilia
which medication can be used to increase factor 8 in haemophilia A and how
Desmopressin
- triggers release of VWF which increases factor 8
which medications can inhibit break down clots and reduce risk bleeding in haemophilia
tranexamic acid
aminocarporic acid
what is the most common inherited bleeding disorder
Von willebrand disease
contrast type 1,2,3 von willebrand disease in terns of effect on VWF and inheritance pattern
Type 1
→ partial reduction in vWF
(autosomal dominant)
Type 2
→ abnormal form of vWF
(autosomal dominant)
Type 3
→ total lack of vWF
(autosomal recessive)
which condition does this describe
prolongued bleeding time, prolonged APTT, factor 8 levels may be reduced
von willebrand disease
describe bleeding time in haemophilia
normal, APTT is prolonged
normal bleeding time, prolonged APTT, no factor 8
what condition does this describe
haemophilia A
normal bleeding time, prolonged APTT, no factor 9
what condition does this describe
haemophilia B
Tx for Von willebrand disease
tranexamic acid for mild bleeding,
desmopressin,
factor 8 concentrate
which medication can cause bone marrow suppression and hence pancytopenia
methotrexate
what type of anaemia is aplastic anaemia
normochromic normocytic anaemia
investigations for pancytopenia
FBC and blood smear
Then,
- bone marrow biopsy to check if bone marrow suppression is the cause
- LFTs / B12 and folate / coagulation / viral serology / autoimmune profile
- screen for PNH and IBMFS
(PNH = paroxysmal nocturnal haemoglobinuria, IBMFS = inherited bone marrow failure syndrome)
pancytopenia tx
RBC and platelet transfusion
bone marrow / stem cell transplant
what is polycythaemia
increase in Hb conc
what is relative vs absolute (true) polycythaemia
○ Relative Polycythaemia
⇒ normal red cell mass but low plasma volume
-Relative Causes
→ dehydration, stress
Absolute (True) Polycythaemia
⇒ increased red cell mass
- causes hyper-viscosity (mucosal bleeding, neurological symptoms, visual changes, thrombosis)
what is hyperviscocity syndrome and which type of polycythaemia does it present in
presents in absolute/true polycythaemia which is when there’s an increased red cell mass
triad of:
mucosal bleeding
neurological symptoms (headache, dizzy)
visual changes
and increases risk of thrombosis
what is primary vs secondary polycythaemia
primary (aka Polycythaemia Vera)
- EPO independent
therefore EPO is LOW
- can be caused by Budd-Chiari syndrome
- can cause acute myeloid leukaemia or myelofibrosis
secondary
- EPO dependent (driven by excess EPO
therefore EPO is high
- due to either
chronic hypoxia (COPD, living at high altitude)
or inappropriate increase in EPO (hepatocellular/renal carcinoma, EPO abuse by athletes)
which mutation do you look for if you suspect polycythaemia vera
positive JAK 2 gene mutation
symptoms of polycythaemia
red face
painful burning and redness of hands/feet
pruritus - WORSE in WARM water
splenomegaly
hyoerviscosity syndrome (mucosal bleeding, neurological symptoms, visual changes )
what are Hb, haematocrit and platelet levels in polycythaemia
all elevated
management/tx for polycythaemia
phlebotomy (venesection)
aspirin
cryoreductive therapy
JAK2 inhibitor (ruxolitinib) for polycythaemia vera
what condition increases risk of both acute leukemias
down syndrome
what is the most common leukaemia in children
Acute lymphoblastic leukaemia
what age is acute myeloid leukaemia seen in
adults, 65 yrs
what is the most common cause of AML
pre-existing haematopoietic disorders eg aplastic anaemia, myeloprolifertaive disorders
what is seen on cytology in AML
Auer rods ( large pink/red stained needle-like structures)
what are the distinguishing signs/symtpoms between ALL and AML
ALL - has lymphadenopathy and fevers
AML - does NOT have lymphadenopathy and fevers
describe the levels of cells in acute leukaemia
everything low - neutropenia, thrombocytopenia, anaemia
EXCEPT blasts which are high
what is present on peripheral blood smear in acute leukaemia
presence of blast cells (immature WBCs)
how to confirm diagnosis of acute leukaemia
Bone Marrow Aspiration & Biopsy
→ Hypercellular marrow with >20% of cells being lymphoblasts (ALL).
what is the most common type of leukaemia in adults
CLL (chronic lymphocytic leukemia)
what is Richter transformation and what are signs of it
when chronic lymphocytic leukaemia transforms to become non hodgkins lymphoma
(presents with lymph node swelling, fever, weight loss, night sweats)
the proliferation of which cells causes chronic lymphocytic leukaemia
B cells (lymphocytes)
what is seen on blood film in chronic lymphocytic leukaemia
smudge ie smear cells
thromobotic risk level in all the different types of leukaemia
acute: low thrombotic risk (thrombocytopenia)
CLL: low thrombotic risk (thrombocytopenia)
CML: hyper-viscosity so higher thrombotic risk
the proliferation of which cells causes chronic myeloid leukaemia
granulocyte
in which type of leukaemia is there an increase in all the cells whilst the others dont
CML
which gene mutation is associated with CML
philadelphia chromosome
reciprocal translocation between chromosome 9 and chromosome 22.
The resulting BCR-ABL gene codes for a fusion protein that has tyrosine kinase activity in excess of norma
levels of leukocyte alkaline phosphatase (LAP) in CML
low
which medication can be used in tx of CML
tyrosine kinase inhibitor (Imatinib)
what is the urgent referral criteria for leukaemia in 0-24 yr olds
refer for immediate specialist assessment for leukaemia if unexplained petechiae or hepatosplenomegaly (urgent FBC)
mx of leukemia
chemotherapy
radiotherapy
stem cell transplant
what is seen on blood film in ALL
blast lymphoid cells
what is seen on blood film in CML
left shift
which type of leukaemia presents with massive splenomegaly
CML (think, the one that has the higher levels of cells)
contrast hogdkin and non Hodgkins lymphoma
hodgkin
- B cells
- bimodal age distribution
- due to EBV, or immunosuppression (eg HIV)
- affects lymph nodes above diaphragm
- contiguous spread, only affects a single group of nodes
- extra nodal involvement is rare
- B symptoms are early, and are also a sign of bad prognosis
- Reed Sternberg cells
- better prognosis, less common
non hodgkin
- B or T cells
- increases with age
- due to chromosomal translocation, infection, autoimmune conditions, immunodeficiency
- affects multiple node groups
- non contiguous spread
- extra nodal involvement is common
- neoplastic cells of B cell lineage
- B symptoms are later
- worse prognosis, more common
what type of lymphoma are Reed Sternberg cells associated with
hodgkin lymphoma (particularly, mixed cellular hodgkin lymphoma)
what are the 4 types of hodgkin lymphomas
nodular sclerosing
- most common
- good prognosis
- females
- lacunar cells
mixed cellularity
- good prognosis
- many Reed Sternberg cells
lymphocyte predominant
- best prognosis
lymphocyte depleted
- rare
- worst prognosis
symptoms of hodgkin lymphoma
painless lymphadenopathy most commonly involving the cervical or supraclavicular nodes.
Involvement of single group of lymph nodes.
Alcohol induced pain.
Pruritus.
B symptoms.
symptoms of non hodgkin lymphoma
rubbery painless lymphadenopathy associated with fatigue.
Splenomegaly.
Extranodal disease = GI (dyspepsia, dysphagia, abdo pain), bone marrow (bone pain), neurological (headache).
Affects multiple nodes
which type of lymphoma has a starry sky appearance on microscopy
burkitt’s lymphoma (subtype of non hodgkin lymphoma)
what patients is a burkitt’s lymphoma common in
HIV pts
what can happen as a result of a burkitt’s lymphoma’s response to chemotherapy
Chemotherapy tends to produce rapid response which can cause tumour lysis syndrome
Tumour Lysis Syndrome → PUKE Calcium = phosphorus, uric acid, potassium elevated. Calcium reduced.
Ix for hogdkin vs non Hodgkins lymphoma
hodgkin
- histology and biopsy
(reed Sternberg cells)
non hodgkin
- lymph node biopsy and immunohistochemistry
what does elevated LDH mean for lymphomas
poor prognosis
what imaging modality and scoring system is used for staging lymphomas
PET-CT CAP → staging (“lugano classification” based on the Ann-Arbor Staging)
Stage 1 - One node affected
Stage 2 - More than one node affected on the same side of the diaphragm
Stage 3 - Nodes affected on both sides of the diaphragm
Stage 4 - Extra-nodal involvement e.g. Spleen, bone marrow or CNS