Haematology Flashcards
In the treatment of MDS, what are predictors of clinical response to lenolidomide?
Predictor of GOOD response: isolated del(5q) as it suggests mild disease
Predictor of POOR response: low plts
What is the function of ADAMTS-13? What happens in TTP?
ADAMT-13 normally cuts the long vWF long multimers (secreted from endothelial cells) into shorter pieces preventing them from attaching to platelets and causing unintended clots. With TTP there is a ADAMTS-13 deficiency, so platelet clots aberrantly arise.
What is Donath-Landsteiner syndrome?
AKA PAH (paroxysmal cold haemaglobinuria), is an immune-mediated post-infective cause of haemolytic anaemia due to IgG autoantibodies to the P-antigen on RBC.
Which condition might ‘sausage links’ on fundoscopy suggest?
Hyperviscosity syndrome - most likely due to Waldenstrom’s macroglobulinaemia, although multiple myeloma is possible.
If spherocytes are noted on a blood film, which is the next test that should be conducted? What conditions are in the DDx?
DAT (direct antigen test) should be conducted to diffrentiate between:
DAT negative: hereditary spherocytosis
DAT positive: variety of immune mediated haemolytic anaemias (autoimmune, lymphoproliferative, drugs, infection)
What is the DDx for DAT positive spherocytosis?
Causes of immune-mediated haemolytic anaemias: lymphoproliferative disorders, cancers, autoimmune diseases, drugs and infection.
Which types of VWD are autosomal positive and negative?
Mild (1 / 2A / 2B / 2M) are autosomal DOMINANT
Severe (2N / 3) are autosomal RECESSIVE
What 4 parameters is the platelet functon test PFA-100 dependent upon?
- Platelet function (obviously)
- Platelet number (logical)
- Haematocrit (dilutional effects)
- vWF levels (stabilises platelets)
What are the causes of sickle cell crisis, which of these is the most common?
Aplastic crisis in sickle cell anaemia is a temporary arrest of RBC production. Most common cause is parvovirus B19, other triggers include (SHE): streptococcus, hydroxyurea, EBV.
Sickle cell anaemia is diagnosed through which 3 tests?
- Blood film: reticulocytes and signs of hyposplenism (Howell-Jolly bodies and target cells)
- Hb electrophoresis
- Sickle cell solubility test
What is Hb Barts? What condition does it cause?
Alpha-thalassaemia due to abnormalities in the gene loci for all 4 globulins of Hb. Hb Barts is a cause of non-immune hydrops foetalis (accumulation of fluid/oedema in 2 foetal compartments)
What is predictor of poor prognosis in CLL?
For CLL a chromosome 17p deletion on FISH is suggestive of poor response to chemotherapy.
In a patient with normal renal function, when should a NOAC be ceased prior to:
- Low risk procedure
- High risk procedure
Discontinuation of a NOAC (factor X1 inhibitor) in a patient with normal renal function:
- Low risk procedure = 1d
- High risk procedure = 3d
What are the 5 components of the DIC screen?
DIC screen:
Bleeding (3): low platelets, high PT/APTT, blood film (low platelet and platelet fragments i.e. schistocytes)
Clotting (2): low fibrinogen, positive D-dimer
What is the strongest predictive factor for DVT recurrence?
Obvious.
Strongest predictive factor for recurrent DVT is a previous DVT, especially if unprovoked (8% unprovoked vs. 4% provoked)
In a patient with impaired renal function (eGFR<30), when should a NOAC be ceased prior to:
- Low risk procedure
- High risk procedure
Discontinuation of a NOAC (factor X1 inhibitor) in a patient with impaired renal function:
- Low risk procedure = 3d
- High risk procedure = 4d
What elements in the FBC are prognostic in CLL?
Prognostic features for CLL in FBC: anaemia and/or thrombocytopenia (Binet or modified Rai staging)
What is the modified Rai-staging for CLL?
Modified Rai staging for CLL:
Low = elevated WCC (bone or marrow)
Intermediate = elevated WCC + LNs (anywhere)
High = anaemia/thrombocytopenia +/- LNs
What is Heyde’s syndrome?
Heyde’s syndrome:
AS
vWD (type IIa)
GI-angiodysplasia
How does scurvy cause a macrocytic anaemia?
Scurvy (vitamin C deficiency) may cause macrocytic anaemia via:
- Defective folate metabolism (co-factor for reduction of folate)
- Oxidative haemolysis as ascorbic acid is an important anti-oxidant.
True/False: Ascorbic acid is a potent oxidant.
False: Ascorbic acid is a potent reductant (i.e. anti-oxidant) and therefore donates electrons.
What is the treatment of scurvy?
Rx for scurvy – replace vitamin C, should recover in 3 months.
Which two important metals are reduced by ascorbic acid in the body?
Ascorbic acid (vitamin C) reduces iron and copper in the body.
Which type of anaemia do the following conditions cause? Hypthyroidism Scurvy Zollinger-Ellison Syndrome HRT therapy Ulcerative colitis
Macrocytic anaemia: hypothyroidism, scurvy, HRT therapy
Microcytic anaemia: Zollinger-Ellison Syndrome, Ulcerative colitis.
What is a common feature of HUS that if absent renders HUS unlikely.
Bloody diarrhoea
What gene product is often seen in CML? How common is this?
The product of the bcr/abl gene is a constitutively active tyrosine kinase that is seen in 97% of cases of CML.
What is the Philadelphia chromosome? With which condition is it associated with?
t(9;22)(q34,q11)
Abnormality of chromosome 22 which has part of chromosome 9 translocated to it - forms fusion gene bcr/abl - associated with CML.
True/False: presence of the philadelphia chromosome is necessary and sufficient to diagnose CML.
False - sensitive but non-specific.
t(9:22)(q34;q11) is found in 95% of CML. However it is also found in ALL (30% adults and 10% children) and occasionally AML.
In simple terms describe the following haematological disorders:
- Leukaemia
- Myelodyplasia
- Myeloproliferative Disorder
- Lymphoma
- Plasma cell dyscrasias
- Leukaemia: leukaemia cells in blood and bone marrow
- Myelodyplasia: insufficient production of mature blood cells +/- leukaemia cells in blood/bone marrow
- Myeloproliferative Disorder: excessive production of mature blood cells
- Lymphoma: lymphoid cancers in lymphoid containing tissues
- Plasma cell dyscrasias: increased plasma cells in bone marrow + paraprotein (monoclonal Ig - M-band) +/- end-organ damage
What are the haemopoetic tissues of the body?
- Bone marow
- Liver
- Lymphoid organs (LNs / thymus / spleen)
True/False: most haematological malignancies are acquired and occur spontaneously.
True - majority of mutation are spontaneous.
What haematological malignancies is EBV associated with (3)?
- Hodgkin lymphoma
- Burkitt lymphoma
- Post-transplant lymphoproliferative disorder
What haematological malignancies is HTLV-1 (human T-lymphotrophic virus 1) associated with (1)?
Acute T-lymphoblastic leukaemia/lymphoma.
What haematological malignancies is HIV associated with (2)?
- DLBCL (including cerebral DLBCL)
2. Hodgkin lymphoma
What haematological malignancies is HHV-6 (human herpes virus 6) associated with (1)?
Primary effusion lymphoma
Chemotherapy may cause which 2 forms of treat-related haematological disorders (2)?
AML or MDS
Radiotherapy may cause what forms of secondary haematological disorders (3)?
Acute leukaemia
CML
MDS
Hair dye can cause what type of lymphoma?
Follicular lymphoma
What are the 4 main types of leukaemia?
AML - Acute myeloid leukaemia
ALL - Acute lymphoblastic leukaemia
CML - Chronic myeloid leukaemia (aka Myeloproliferative Disorder)
CLL - Chronic lymphocytic leukaemia
In simple terms for AML:
- How is diagnosed?
- Prognostication?
- Therapy?
- Diagnosis: blood film + bone marrow aspirate/trephine
- Prognostication: cytogenetics / molecular tests
- Therapy: chemotherapy / allogenic stem cell transplantation
In the diagnosis of AML describe the:
- Blood film or bone marrow Bx
- Cytochemistry
- Imunophenotyping (flow cytometry)
- Blood or bone marrow: >20% blasts with Auer rods (suggestive of myeloid leukaemia)
- MPO (myeloperoxidase) positive
- Myeloid Ags (CD13, CD33)
What is the ‘strongest’ adverse prognostic factor in AML?
Age > 60yrs - strongest prognostic factor
Despite the advent of fancy cytogenetic and molecular studies.
What is the key cell type implicated in GVHD (graft versus host disease) in allogenic stem stem transplants?
A. B-cells B. NK cells C. Dendritic cells D. T-cells E. Macrophage
T-cells
GVHD is a lymphocyte-mediated process.
How is iron absorbed in the body in 4 steps?
- In the duodenum ferric iron (Fe3+) converted to ferrous iron (Fe2+) via Vit C and cytochrome B and transported into the duodenal enterocyte via apical DMT 1 (divalent metal transporter 1).
- Once inside the enterocyte it is converted back to ferric (Fe3+) iron and stored as FERRITIN.
- Ferrous (Fe2+) iron may continue to be absorbed into the blood via FERROPORTIN on the basolateral membrane. It is then converted to ferric (Fe3+) so as to bind to TRANSFERRIN.
- Ferric-transferrin complex is transported to bone marrow and liver there it acts upon transferrin receptors on RBC for Hb synthesis.
How does hepcidin affect iron metabolism?
What occurs in iron overload?
HepcidIN = INbihibition of ferroportin = INhibits Fe absorption.
Fe overload –> hepcidin from liver –> internalisation of ferroportin –> reduced iron absorption
What occurs to transferrin receptors in iron deficiency?
Upregulated.
Which 5 sites migh haemosiderin be found in haemochromatosis?
liver, pancreas, heart, joints and skin.
Give 6 acquired causes of iron overload.
Smacked! - SMACTT
Sideroblastic anaemia MDS Aplastic anaemia CLD Transfusions of PRBCs Thalassaemia
What are the treatment options for acquired causes of iron overload?
Give SEs of these agents.
Iron chelators:
Desferasirox (PO) - SE: diarrhoea, renal impairment
Ferriprox (PO): SE: agraulocytosis
What are the 4 stages of fibrin formation/coagulation?
- Initiation
- Propagation
- Termination
- Resolution
With fibrin formation/coagulation what does the first stage ‘initiation’ entail?
Initiation:
- vessel injury and exposure to tissue factor
(III)
- interaction with F7 (extrinsic pathway)
With fibrin formation/coagulation what does the second stage ‘propagation’ entail?
Propagation:
- coagulation cascade (mainly ‘intrinsic’ pathway) for amplification
- F12 –> F11 –> F9 –> F8 + vWF
- Converges to generate activated F10a
- Formation of fibrin plug and platelet aggregation
With fibrin formation/coagulation what does the third stage ‘termination’ entail?
Termination:
- Anti-thrombotic control mechanisms (protein C/S and antithrombin)
- Downregulates clotting response and contains the thrombus
With fibrin formation/coagulation what does the fourth stage ‘resolution’ entail?
Resolution:
- Removal of clot via fibrinolysis
- plasmin (tPA released by endothelium) breaks down cross-linked fibrin to form fibrin degradation products e.g. D-dimer
What are the 4 endogenous anticoagulants in a healthy individual?
From which structure are they released?
PUT:
Proteins C + S
Urokinase
tPA
All released from endothelium to break down fibrin clots.
Which parts of the coagulation cascade is tested by PT?
What else is it useful for?
PT = Extrinsic pathway (TV factors: 2, 7, 9, 10)
PT also used in liver disease, vit K deficiencies and warfarinisation.
Which parts of the coagulation cascade is tested by APTT?
What else is it useful for?
APTT = Intrinsic pathway (12, 11, 9, 8 + vWF)
APTT also for detecting anticoagulants:
- Lupus anticoagulant
- Heparinisation (anti-thrombin III)
Outline the common pathway of the coagulation cascade.
Intrinsic and Extrinsic pathways converge at F10a:
- prothrombin (F10a) thombin (F2)
- thromin (F2) activates F13 to F13a and converts fibrinogen (F1) to fibrin
- fibrin and F13a allow cross-linking to form stable fibrin clot.
Which part of the coagulation cascade is tested by thrombin time (TT)?
In the context of a coagulopathy, what does a normal TT suggest?
Measure conversion of fibrinogen to fibrin.
If TT is normal, there is an upstream problem i.e. F2, F5 or F10.
If PT, APTT and TT are all deranged, what are the DDx (5)?
- Combined factor deficiency
- Presence of inhibitors
- Deficiency of F2, F5 or F10
- Liver disease
- DIC (as it is tissue factor dependent.
Which parts of the coagulation cascade is tested by Reptilase time (RT)?
Detects reduced fibrinogen i.e. fibrin clots cannot form.
Prolonged TT and normal RT = heparin contamination.
Prolonged TT and prolonged RT = hypofibrinogenemia or dysfibrinogenemia
Haemophilia A is due to which factor deficiency?
F8 (remember: Ate)
Haemophilia B is due to which factor deficiency?
F9 (benign: B-nine)
For Haemophilia A outline the risk of bleeding in accordance with % activity of the deficient factor.
% activity of F8:
> 50%: no bleeding
> 25%: bleeds with severe trauma
> 5%: NO spontaneous bleeding, bleeds with trauma/surgery and slight bleeding with minor trauma.
< 1%: Spontaneous bleeding (knee > elbow > ankles)
How do you differentiate between a time-dependent inhibitor and lupus anticoagulant on a mixing study?
What is the most likely time-depedent inhibitor?
Lupus anticoagulant = prolonged APTT fails to correct with mixing study (i.e. remains prolonged)
Time dependent inhibitor = prolonged APTT corrects with mixing study
Most likely cause: F8 inhibitors in acquired Haemophilia A.
What are the constituents of cryoprecipitate?
When is cryoprecipitate indicated (2)?
F8 + vWF
Fibrinogen
F13 (for fibrin cross-linking)
Fibronectin
Indications:
- DIC
- Fibrinogen deficiencies/dysfunction
What factors are in Prothrombinex?
Which of these is present at low levels?
What are the indications and contraindications?
TV factors: 2, 7, 9, 10
Indication: warfarin reversal (coupled with giving Vit K)
Contraindication: DIC, AMI, thrombosis, CVA
True/False: the TV factors (2, 7, 9, 10) are localised to the platelet membrane.
True.
When is recombinant factor 7 indicated?
Factor deficiencies (e.g. factor 9) or factor inibitors (time-dependent inhibitor of factor 8)
What is DDAVP, what does it do and when is it used?
DDVAP (desmopressin) is a synthetic analogue of ADH that:
- Increased F8 + vWF
- Activated platelet aggregation (via vWF)
Indication:
- Uraemic bleeding (AKI/CRF)
- Mild Haemophilia A and VWD
What is MOA of transexamic acid?
What are the indications?
Transexamic acid blocks plasmin and therefore inhibits fibrinolysis.
Indications:
- Mucocutaneous bleeds
- GI bleeds
- Tumours that secret fibrinolysis proteins
Outline fibrinolysis.
Plasminogen > (tPA/urokinase/F11a/F12a) > plasmin
Fibrin > (plasmin) > degradation products
Fibrinogen > (plasmin) > degradation products
What is the mechanism of GVHD?
Which donor-recipient populations are at greatest risk?
Donor T-cells recognise the recipients Ag as foreign leading to delayed haemolytic transfusion ( > 2/52 after ASCT or transfusion).
Therefore HLA mismatch are at greatest risk.
Patient may become pancytopenic.
What prophylaxis is given to prevent GVHD?
What consideration is required for PRBC transfusions?
Prophylaxis with ASCT:
- Calcineurin inhibitors (CNI): tacrolimus / cyclosporin A
- Adjuncts: MTX or MMF
Irradiated blood products may prevent GVHD.
How is GVHD treated?
Immunosuppression (anything from steroids to TNFi)
What is the mechanism of haemolytic transfusion reactions?
ABO incompatibility - donor Ag interacts with patients pre-existing allo-Ab
Patients develop ATN: fevers, haemolysis, back pain DAT positive.
What is non-haemolytic febrile transfusion reactions?
Donor lymphocytes interact with recipients antibody, limited but still warrant investigation.
What is TRALI?
Transfusion Related Acute Lung Injury - occurs 6h after transfusion.
Mechanism: donor antibodies interact with recipients leukocytes leading to:
- activation of complement and cytokine storm
- APO/ARDS
Remember: ‘trA-Li’ = Ab-to-Leukocytes
What is the utility of measuring anti-Xa levels?
Measures the adequacy of anticoagulation with LMWH:
Low anti-Xa level = adequate
High anti-Xa level = no adequate (insufficient)
What is LMWH (low-molecular weight heparin)?
Give an example.
Heparin is a naturally occurring polysaccharide that inhibits coagulation.
Natural heparin consists of molecular chains of varying lengths, or molecular weights (5000 to over 40,000 Daltons)
LMWHs consist of only short chains of polysaccharide. LMWHs average molecular weight of less than 8000 Da.
Example: enoxaparin (Clexane)
What is the mechanism behind haemolytic transfusion reactions?
What are the clinical manifestations?
ABO incompatibility: donor’s Ag interacts with patient’s pre-existing allo-Ab.
Clinical features:
1. Fever +/- back pain
2, ATN
3. DAT positive
What is the mechanism behind febrile non-haemalytic transfusion reactions?
Donor’s ‘lymphocytes’ interact with recipients Ab. Often self limiting but it’s necessary to exclude DDx for fevers.
What is the approach to warfarin reversal in cases of overdose or poisoning in a patient not usually on warfarin?
How frequently should INR be monitored?
- Single-dose activated charcoal if < 1h from gestation.
- Vit K (phytomenadione) 10-20mg (PO/IV)
- If actively bleeding then Prothrombinex + FFP.
Monitor INR 6-12 hourly.
What is the approach to warfarin reversal in ‘over-anticoagulation’ of somebody already on warfarin?
Depends on INR:
INR < 5 = omit next dose
INR 5-9 = vit K (2mg PO or 1mg IV)
INR > 9 (low risk of bleed) = vit K (5mg PO or 1mg IV)
INR > 9 (high risk of bleed) = vit K 1mg IV +/- Prothrombinex + FFP.
Significant bleed = vit K 5-10mg IV + Prothrombinex + FFP
Match the following mutations with their haematological conditions and if relevant, indicate whether they are good/bad prognostic factors:
- t(9:22)
- JAK2
- t(15:17)
- t(8:21)
- t(9:22) = Bcr Abl (Philadelphia), classically CM but may also present in AML/ALL.
- JAK2 = polycythaemia rubra vera
- t(15:17) = APML, suggests good prognosis
- t(8:21) = AML, suggests good prognosis
(9: 22 minus one is 8:21 = CML minus one maturation step is AML)
Match the following blood film findings to the respective haematological condition:
- Tear drop RBC
- Smear cells
- Auer rods
- Pelger cells
- Tear drop RBC = Myelofibrosis
- Smear cells = CLL
- Auer rods = AML
- Pelger cells = Myelodysplasia (also AML/CML)
Which haematological conditions are associated with the following conditions:
- Budd Chiari Syndrome
- CD5 and CD 19 expression
- Budd Chiari Syndrome = polycythaemia rubra vera (PRV)
2. CD5 and CD 19 expression = CLL
Match the following blood film findings to the respective haematological condition:
- Howell Jolly Bodies
- Pencil cells
- Rouleaux cells
- Hypersegmented neutrophils
- Oval macrocytes
- Howell Jolly Bodies = asplenia (functional or splenectomy)
- Pencil cells = Fe-deficiency (pencil skin girls are iron deficient)
- Rouleaux cells = Multiple myeloma and Waldenstroms
- Hypersegmented neutrophils = B12 deficiency
- Oval macrocytes = B12 deficiency
True/False: methylmalonic acid (MMA) is specific but not sensitive for B12 deficiency.
False: MMA is sensitive but not specific to B12 deficiency.
What is found on the blood film in G6PD deficiency?
Blister cells (RBC blisters)
Bite cells (looks like Pacman) if with haemolysis
If a blood film has elliptocytes/ovalocytes?
SE Asian Ovalocytosis
What haematological conditions are suggested by:
- Heinz bodies
- Target cells
- Fragmented cells
- Heinz bodies = beta-thalassaemia (BEANS means Heinz) due to excess alpha globulins
- Target cells = Thalassaemia or Sickle cell (any defective globin chain synthesis)
- Fragmented cells = DIC
What causes acanthrocytes (spur, thorn or spiculated cells) in the blood film?
Splenectomy
Cirrhosis
Haemolytic anaemia
Thalassaemia
True/False: nucleated RBCs are always pathological.
Nucleated RBCs = immature blood cells which are normal in infants (HbF) but abnormal in adults suggesting Thalassaemia.
What conditions are suggested by cold agglutination (rouleaux in cold, spherocytes, polychromasia)?
Paroxymal Cold Haemaglobinuria OR
Cold Agglutinin Disease (IgM, associated with Lymphoma and Mycoplasma)
What is the treatment of polycythaemia rubra vera (PRV) and essential thrombocyopenia (ET)?
- Aspirin for clot prophylaxis
- Hydroxyurea for splenomegaly
- Venesection
How is CML diagnosed?
- Bcr-Abl t(9:22)
- Neutrophilia
- Immature myeloid progenitor cells
- Splenomegaly
What is the risk of CML transformation in AML?
70% risk
What predictive index is used in CML?
Sokol index predicts how well a patient will respond to therapy and consists of (SPAB): Spleen size Platelets Age Blast percentage
What is the management of CML?
Oral TKI (Imatinib/Nilotinib/Dasatinib) work well as they confer > 90% disease-free survival (DFS)
Allogeneic Stem Cell Transplant is NOT much used anymore.
What is the epidemiology of AML?
- Mid-60s - usually presents in the adult population
- Males > Females
How is acute AML diagnosed?
‘we need 13 to 33 CDs to play this GAME!’
- CD13 and CD33 myeloid Ags on flow cytometry
- Genes: t (9:22) Bcr-Abl = BAD and t(8:21) = GOOD
- Auer rods
- MPO (myeloperoxidase positive)
- Erythroblasts (RBC blasts) > 20%
What are the poor predictive factors for AML/
‘OLD people shouldn’t FLIT their Kits in Philadelphia - it’s a BAD look!’
Age > 60 is the WORST predictive factor (treatment makes no difference)
Philadelphia chromosome Bcr-Abl t(9:22) = BAD
FLiT3 mutation requires early Allogeneic BMT
Kit mutation
What are the good predictive factors for AML?
t(8:21) and NPMI mutation
What is the management of AML?
- Cytarabine (pyrymidine analogue - anti-metabolite) or Anthracyclines (rubicins)
- Allogeneic BMT for relapse (Allo = another person)
What is the mechanism of Disseminated Intravascular Coagulopathy (DIC)?
- Bleeding: consumption of platelets and coagulation factors when the clotting cascade is activated.
- Clotting: dysregulation of the clotting cascade leading to uncontrolled thrombin generation and fibrin deposits in microcirculation.
How should DIC be managed?
Consider ICU.
FFP, cryoprecipitate and/or platelets
A patient presents with epistaxis/bleeding, easy bruising, fatigue and pancytopenia. BM shows blasts with Auer rods.
What is the diagnosis and the likely genetic mutation?
Diagnosis: APML with DIC
APML:
- usually presents with DIC
- t(15:17) translocation = good prognosis.
What is the treatment of APML?
ATRA and Arsenic:
- ATRA (All-trans Retinoic Acid) forces the differentiation of promyelocytes (myeloblasts) into normal granulocytes
- Arsenic is chemo-agent with unknown MOA, but promotes apoptosis, may prolong QTc.
Patient presents with lymphadenopathy, hepatosplenomegaly, bruising, mouth ulcers, petechiae, menorrhagia and fatigue. FBC reveals anaemia, leukocytosis and thrombocytopenia. What is the likely diagnosis?
Acute lymphocytic leukaemia
