Week 4 - Haematology Flashcards
Describe the action of hydroxycarbamide in the treatment of essential thrombocytopenia
Gentle chemotherapy, ribonucleotide reductase inhibitor resulting in reduced production of deoxyribonucleotides, affects all blood cell lines
Describe the pharmacological characteristics of warfarin
- Oral vitamin K antagonist (taken once daily)
- Failure of gamma-carboxylation of Glu residues –> dysfunction of factors II, VII, IX and X
- Delayed onset and offset
- Effective half life approx. 36 hours
- High inter-individual variability
- Narrow therapeutic window
- May drug and food interactions
- Requires regular INR monitoring
What protein is produced by abnormal plasma cells in plasma cell myeloma?
- In most myeloma patients, abnormal plasma cells produce an abnormal ‘monoclonal protein’ called a paraprotein or ‘M’ protein
- 5 different types (IgG, A, M, D, E - G and A most common)
- IgE very rare
- IgM myeloma does exist but rare - more commonly associated with lymphoma e.g. Waldenstroms macroglobulinaemia
- Sometimes only part of the Ig molecule is produced - ‘light chain myeloma’, hard to detect (present with renal impairment)
- Rarely no Ig produced - ‘non-secretory myeloma’
What are the aims of management of acquired warm type haemolytic anaemia?
Primary duty of haematologist is to halt the haemolytic process and thereafter to exclude any possible underlying causes
Describe the mechanism of action of tPA derivatives
- Alteplase, Tenecteplase, Reteplase
- Activates plasminogen
- Plasmin cleaved from plasminogen
- Plasmin breaks down fibrin
- Relatively selective for clot bound plasminogen
- Minimal unwanted fibrinogenolysis
Describe the survival rates of ALL
5 year survival rate for children - 90%
5 year survival rate for adults - 40%
What are the indications for anti-platelet drugs?
Cardiovascular disease
- Acute MI
- Aspirin indefinitely
- Ticagrelor/clopidogrel for up to 12 months
- +/- tirofiban acutely
- Secondary prevention CVD
- Aspirin
Cerebrovascular disease (without AF)
- Acute stroke/TIA/secondary prevention
- Clopidogrel
- Dipyridamole + aspirin if clopidogrel not tolerated
Peripheral vascular disease
- Clopidogrel
- Aspirin if clopidogrel not well tolerated
List the causes of warm type autoimmune haemolytic anaemia
- 55-60% of cases idiopathic/primary
- Secondary causes include
- Lymphoproliferative disorders e.g. chronic lymphocytic leukaemia and non-Hodgkin’s lymphoma
- Other neoplasms
- SLE (systemic lupus erythematosus) or other connective tissue disorders
- Drugs
How is acute myeloid leukaemia managed?
- Intensive chemotherapy +/- stem cell transplant
- For patients <60-65
- 5 year survival approx. 50%
- Low dose chemotherapy
- Patients >60-65
- 5 year survival approx <10%
- Supportive care only
- Older patients only, major comorbidities
- Median survival 3-6 months
What is required for blood coagulation?
- Functioning platelets
- Functioning endothelium
- Coagulation factors
Define thrombocytosis
Too many platelets
How is myeloma treated?
- Asymptomatic myeloma (smoldering) - watch and wait
- Symptomatic myeloma (determined by CRAB criteria) - requires treatment
- All patients receive chemotherapy usually including a steroid and thalidomide
- Radiotherapy - e.g. severe bone pain
- Supportive therapy
- Bisphosphonates - reduce pain, pathological fractures, hypercalcaemia and need for radiotherapy
- Blood transfusion/EPO
- Surgery
- Interventional radiology
- Autologous transplant (younger, fitter patients) versus no transplant
- Can receive transplant up to 70 y/o
How has the prognosis of chronic myeloid leukaemia been improved?
Prognosis improved by introduction of Imatinib - blocks transformation of BCR-ABL gene and so pathways which cause unregulated proliferation
How is Fanconi’s anaemia treated?
- Gold standard therapy is allogenic stem cells transplant - related donors need to be screened for FA
- Improve blood cell count - supportive care, corticosteroids, androgens (oxymethalone)
- Lifetime surveillance for secondary tumours
- Possibility of gene therapy in future where faulty FANC gene is replaced
Where is red bone marrow found?
Mainly in the inner mass of flat bones e.g. pelvis, sternum, skull, ribs, vertebrae and scapulae, also the spongey matrix at the proximal ends of the femur and humerus
When is streptokinase ineffective?
- Derived from streptococci bacteria
- Antigenic
- Recent step infection/previous use of streptokinase - can be rendered ineffective
How is intermediate essential thrombocytopenia treated?
Aspirin +/- hydroxycarbamide (cytoreductive agent)
List the risks of splenectomy
- Acute risks of surgical operation + long-term specific risks
- ‘Sieves’ out microorganisms from the bloodstream, particularly encapsulated microorganisms - streptococcus pneumoniae, haemophilus influenzae and neisseria meningitis
- Organisms can cause overwhelming post-splenectomy infections - patients must be vaccinated against these organisms pre-operatively + life long antibiotic prophylaxis (penicillin V) recommended
- Patients must be informed of risk, understand they require prompt antibiotics in the event of infection and carry a splenectomy card with them at all times
How can secondary haemostasis be assessed?
- Prothrombin time (PT)
- Activated partial thromboplastin time (APTT)
- Thrombin clotting time (TCT)
- Individual coagulation factor assays
List the signs/symptoms of iron deficiency anaemia
Iron is required for all tissues - typical tissue signs seen as well as haematological symptoms
- Koilonychia - spoon nails
- Atrophic glossitis - pale, smooth, painless tongue
- Angular stomatitis
- Oesophageal web (Plummer Vinson syndrome) - web in oesophagus causes trouble swallowing
Describe the principles of coagulation testing
- Add reagents to PPP
- Perform assay at ‘body temperature’ - 37 degrees
- Time to form clot
- All results expressed as
- Seconds
- Ratio to normal plasma i.e. normal result = 1.0
How are autograft stem cells usually harvested?
- Almost all autografts use mobilised peripheral blood stem cells harvested by aphaeresis
- Patients receive G-CSF +/- chemotherapy to make the stem cells leave the bone marrow so that they can be collected from the blood 2 cannulas in arms, blood cycles into machine set to specific velocity, collect stem cells at interphase
- More recently Mozobil has been used to collect stem cells in patients that have failed to mobilise - inhibits CXCR4
Describe the pharmacological characteristics of heparins
- Bioavailability
- UFH - 30%
- LMWH - 95-100%
- IV half life
- UFH - 45-60 minutes
- LMWH - 2 hours
- Protein binding (plasma and platelet)
- UFH - ++++
- LMWH - +
- Monitoring
- UFH - APTTr 1,5-2.5
- LMWH - none
How is the thrombin clotting time measured?
- Add at 37 degrees - patient’s plasma, bovine thrombin
- Less calcium or phospholipid dependent
- Time to clot
Describe the pattern of inheritance of hereditary spherocytosis
Autosomal dominant
Describe the pathogenesis of sickle cell disease
Mutation in beta globin gene on chromosome 11 - single amino acid substitution at position 6:
- Glutamine swapped for valine = Hb S
- Glutamine swapped for lysine = Hb C
What tools can be used to assess co-morbidities in lymphoma?
- CGA (comprehensive geriatric assessment)
- CIRS (cumulative illness rating scale)
- Haemato-oncology elderly care liaison service
How is folate absorbed?
Mostly in small bowel, 200-400ug, no carrier molecule required
What is thrombophilia?
- Deficiencies of natural anticoagulants
- Antithrombin
- Protein C
- Protein S
- Specific genetic mutations
- Factor V Leiden (resistance to APC)
- Prothrombin gene mutation (increased prothrombin)
How does graft vs host disease usually present?
- Most commonly manifests as a skin rash, jaundice or diarrhoea (skin, liver and gut are organs most commonly affected)
- Can also have dry mouth, dry eyes and breathlessness (due to pulmonary fibrosis)
When does functional IDA with epo therapy occur?
Renal disease
Describe the role of RES macrophages in iron metabolism
- At end of lifespan (120 days) RBC phagocytosed by macrophages of the RES
- Iron released from Haem, stored in macrophages as ferritin (when there is little iron, soluble) or haemosiderin (when there is lots of iron, insoluble aggregates)
How does clonal haemopoiesis occur?
Progenitor acquires somatic mutation or through neutral drift in HSC population
Define myelodysplastic syndromes
- Characterised by dysplasia (abnormal cells) and ineffective haemopoiesis in >1 of the myeloid series
- May have increased myeloblasts
- Multiple sub-types based on morphology and % blasts
Describe the pharmacological treatment of chronic lymphoblastic leukaemia
Chemoimmunotherapy - new combination treatments available have increased cases of complete remission
What can cause a purpuric rash?
- Platelet problem, usually thrombocytopenia - spontaneous purpura seldom occurs with platelet count >20 x 109/l
- Vasculitis i.e. Henoch Schonlein syndrome
- Haemophilia doesn’t affect platelets so doesn’t cause purpuric rash
What is thromboplastin?
Mixture of phospholipids and tissue factor found in plasma, catalyses conversion of prothrombin to thrombin
Describe the structure of RBC and the functional relevance of this structure
Biconcave disc - squeeze in/out of small blood vessels, maximum surface area for gas transfer
Why is haemoglobin used by RBC to carry oxygen?
Able to reversibly bind O2 without undergoing oxidation or reduction
What influences prothrombin time?
- PT depends on
- Factors in extrinsic and common pathways
- Factors VII
- And Factors X, V, II and Fibrinogen
How are Hickman lines used in stem cell transplants?
Central line which goes into chest, over clavicle and feeds into the subclavian vein which is used to take samples, do reinfusions of cells, monitor patient and give antibiotics
What are the clinical consequences of folate deficiency?
- Blood abnormalities - megaloblastic anaemia (leucopenia, thrombocytopenia), RBCs macrocytic (raised MCV) + anisopoiklocytosis
- Growing foetus - 1st 12 weeks deficiency can cause neural tube defect (every woman pregnant/planning pregnancy needs folate supplement)
Describe haemoglobinopathies
Inherited conditions - two types:
1) Relative lack off normal globin chains due to absent genes (thalassaemias)
2) Variant (abnormal) globin chain e.g. sickle cell disease
Describe the side effects of chemotherapy used in AML
- High morbidity - bleeding and infection
- Hair loss, sterility, mucositis, prolonged inpatient stays, psychological element
Describe the clinical staging of chronic lymphoblastic leukaemia
- Stage A
- Features - <3 involved nodes
- Survival 10 years
- Stage B
- Features - >3 involved nodes, liver, spleen
- Survival 7 years
- Stage C
- Features - anaemia of thrombocytopaenia
- Survival 2 years
List the types of division which haematopoietic stem cells can undergo and the consequences of this
- Symmetrical division - both daughter cells become mature RBC, contraction of stem cell numbers
- Asymmetrical division - one daughter cell is a self-renewing stem cell, one becomes a mature RBC, maintenance of stem cell numbers
- Symmetrical division - both daughter cells become self-renewing stem cells, expansion in stem cell numbers
Describe the markers and phenotype of plasma cells in plasma cell myeloma
- Express plasma cell markers e.g. CD138
- Show aberrant phenotype e.g.
- CD19 negative
- CD56 positive
- Cyclin D1 positive
- Light chain restriction
Describe the classification of leukaemia
Leukaemia
- Acute
- Myelodysplastic syndrome/myeloproliferative disease can progress to acute leukaemia
- Myeloid - acute myeloid leukaemia
- Lymphoid - acute lymphoblastic leukaemia
- Chronic
- Chronic lymphoblastic leukaemia (can progress to high grade non-Hodgkin’s lymphoma)
- Chronic myeloid leukaemia (can progress to acute myeloid leukaemia/acute lymphoblastic leukaemia)
Describe the mechanism of action of clopidogrel/ticlidipine (irreversible blockers of ADP receptor)
- Decreases expression of GPIIb/IIIa
- Reduced binding of fibrinogen
At which age is acute lymphoblastic vs myeloid leukaemia most prevalent?
- Acute lymphoblastic leukaemia more prevalent in 0-20 y/o (especially 0-4)
- Acute myeloid leukaemia more prevalent in 40-85 y/o, prevalence increases with age
- Approx. equal incidence in 20-35 y/o - low prevalence compared to young and old age groups
List causes of folate deficiency
- Dietary
- Extensive small bowel disease - coeliac/severe Crohn’s
- Increased cell turnover - haemolysis, severe skin disorders, pregnancy
Describe the management of a major haemorrhage
- 2222 - major haemorrhage call
- State major haemorrhage
- State location and extension number
- Haematologist, lab staff and porter alerted
- Request major haemorrhage pack
- 6U PRC
- 4U FFP
- 1 pooled platelets
- IV access - wide bore x 2
- Grey/brown cannulae
- Level one device - allows rapidly infusion of blood, can hang two units at same time (rate limiting step is size of cannula and vein)
- Can also use dialysis catheter, pulmonary artery catheter sheaths or a rapid infusion catheter
- Bloods - FBC, coagulation screen, fibrinogen, U+Es, LFT, calcium - near patient testing if available
- Tranexamic acid (if trauma <3 hours ago)
- KEEP PATIENT WARM
What is the 1st line treatment for myeloma? What are the side effects?
- 1st line treatment - chemotherapy, MPT (melphalan, prednisolone and thalidomide) in elderly
- Side effects - neuropathy, constipation, increased thrombosis –> LMW heparin
What are clonal haematological malignancies/pre-malignant conditions?
Haematological conditions arising from a single ancestral cell
How does the structure of foetal haemoglobin differ from adult haemoglobin?
Hb F (foetal) - 2 x alpha, 2 x gamma
Hb A (adult) - 2 x alpha, 2 x beta
Hb A2 (more rare adult) - 2 x alpha, 2 x delta
What is the purpose of investigations done in lymphoma?
- Staging - what areas are affected
- Help decide fitness for treatment - renal/liver/ bone marrow function, cardiac/respiratory disease
Describe the chemotherapy treatment used in acute myeloid leukaemia
- Anthracycline and cytarabine based - heavy myelotoxicity
- Most young patients entered into trials
- MRC AML 17, UKALL14, UKALL2011
- Aim to eradicate abnormal clone
Describe the half life, minimum creatinine clearance and side effects vs warfarin of dabigatran
- Half life - 12 hours
- Cmax - 2-3 hours
- Minimum creatinine clearance
- 30 (reduce dose if 30-50ml/min)
- Side effects vs warfarin
- Fewer ICH, possibly more GI bleeds
How is the risk of progression in myelodysplastic diseases determined?
Low risk vs high risk disease established by proportion of blast cells in marrow and cytogenetic profile (MDS vs AML, blast % cut-off is 20%)
Give examples of other myeloproliferative disorders
Mastocytosis
Clonal hypereosinophilic syndromes
Chronic neutrophilic leukaemia
List the causes of anaemia of chronic disease
Infection Inflammation Neoplasia
Where is transferrin synthesised?
Synthesised in hepatocytes - less iron more Tf made, more iron less Tf made
What is the function of the bone marrow stroma?
Provides requirements of the stem cell to enable it to grow and divide.
Cells e.g. macrophages, fibroblasts and fat cells secrete growth factors and adhesion molecules, released by cells into the bone marrow sinus in close proximity to stem cells.
Describe dietary sources of B12
- Synthesised solely by microorganisms
- Meat (esp. liver and kidney), small amount in dairy products
- Normal western diet - 5-30ug/day
- Strict vegan diet is B12 deficient
Give examples of classical myeloproliferative disorders
Polycythaemia rubra vera
Essential thrombocytosis
Myelofibrosis
Describe the risk of thrombosis in antithrombin deficiency
- Antithrombin deficiency - 20-50% risk of thrombosis in Type 1 AT deficiency by age 50
Describe the absorption of iron in the GI tract
Iron absorbed by mature enterocytes in the small bowel
Haem iron (red meat) readily absorbed, non-haem iron (white meat, green vegetables, cereals) more difficult to absorb
Is the spleen enlarged in immune thrombocytopaenic purpura?
No
What new therapies are available for chronic lymphoblastic leukaemia?
- New therapies for p53 mutation/deletion, 11q22 (ATM) mutation
What part of the coagulation cascade is tested by the activated partial thromboplastin time?
Stimulates activation via the intrinsic pathway
List the advantages and disadvantages of umbilical cord blood stem cell transplants
- Advantages - more rapidly available than VUD, less rigorous matching to patient type as immune system naive
- Disadvantages - small amount (adults will often require double cord transplant), slower engraftment, if relapse can’t go back for DLI, expensive (single cord transplant costs £30,000)
Describe the prevalence of chronic lymphocytic leukaemia
- Commonest leukaemia
- Incidence rises with age - median 67yrs
- M:F ratio 2:1
Describe the types of sickle cell disease
Hb SS - more severe, two copies of sickle cell gene Hb SC - less severe
Describe the development of haemolytic disease of the newborn
Usually occurs in 2nd/3rd pregnancy Mother Rh-, father Rh +, baby Rh + Foetal and maternal circulations mix - Rh+ from foetus to maternal circulation Antibodies from mother against foetus
Define leukocytosis
Too many WBC
List rare bleeding disorders
- Fibrinogen deficiency
- FXIII deficiency
- FX deficiency
- FV deficiency
- FII deficiency
- FVII deficiency
- FXI deficiency
How can primary haemostasis by analysed?
- In vivo - bleeding time
- Ex vivo - FBC (platelet count), platelet function
How does diffuse large B-cell lymphoma present?
Wide variation in presentation -
- Lymphadenopathy - usually rapidly enlarging LN mass
- Extra-nodal presentation common (30-40%) -
- Waldeyer’s ring (tonsils)
- GI tract
- Skin
- Bone
- CNS PUO - pyrexia of unknown origin
- Night sweats and weight loss
What causes diffuse large B-cell lymphoma?
High grade lymphoma associated with various translocations and genetic abnormalities, complex karyotype - heterogeneous entity (variable phenotype)
What does a positive direct Coombs test indicate?
AIHA or haemolytic disease of the newborn
What are the contraindications for all DOACs?
- Pregnancy and breast feeding
- Liver disease with cirrhosis +/- coagulopathy
- Some drugs (mostly strong Pgp or CYP3A4 inhibitors or inducers)
What are the main indications for autologous stem cell transplant?
Relapsed Hodgkin’s disease, non-Hodgkin’s lymphoma and myeloma
What are the main indications for allogeneic stem cell transplants?
- Half of all transplants done are for AML
- Acute and chronic leukaemias, reduced lymphoma, aplastic anaemia, hereditary disorders
How is chronic myeloid leukaemia diagnosed?
- Blood film and clinical features
- Molecular test on blood (BCR-ABL PCR/FISH)
- Cytogenetic analysis (‘karyotype’)
- If BCR-ABL negative - not CML
Which patients are treated with transplants in ALL?
- Relapsed patients
- Refractory patients
- Poor risk disease in first complete remission
- Age less than 60 years
- Good performance
What proportion of adult bone marrow is haemopoietically active?
30%
What are the complications of chronic myeloid leukaemia?
- With modern therapy - very few
- Imatinib resistance
- Imatinib intolerance
- Need for 2nd/3rd line TKI inhibitors
- Accelerated phase/blast crisis
How is the prothrombin time tested?
- Add patient’s plasma, thromboplastin (tissue factor and phospholipids)
- Warm to 37 degrees
- Add calcium
- Time to form clot
How prevalent are bleeding complications with warfarin?
- Bleeding complications with Warfarin:
- Fatal haemorrhage - 0.25-0.64% per year
- Major haemorrhage - 1.1-2.7% per year
- Risk increases as achieved INR increases
How does B12/folate deficiency cause red cell abnormalities?
Disparity in rate of synthesis of precursors of DNA, abnormality of cell division, dissociation between nuclear and cytoplasmic development
Ineffective erythropoiesis - death of mature cells whilst still in marrow
List the absolute and relative contraindications to thrombolysis
- Absolute -
- Haemorrhagic stroke or stroke of unknown origin at any time
- Ischaemic stroke in preceding 6 months
- Central nervous system damage/neoplasms
- Major trauma, surgery, head injury within preceding 3 weeks
- GI bleeding within the last month
- Known bleeding disorder
- Aortic dissection
- Relative (discuss with senior staff before withholding) -
- Transient ischaemic attack in preceding 6 months
- Oral anticoagulant therapy
- Pregnancy or within 1 month postpartum
- Non-compressible punctures <24 hours
- Traumatic resuscitation
- Refractory hypertension (systolic BP > 180mmHg)
- Advanced liver disease
- Infective endocarditis
- Active peptic ulcer
- Terminal illness
How is GvHD prevented?
Conditioning therapy before transplant includes drugs to prevent GvHD - usually immunosuppressive agents
What is the treatment for IDA?
- Investigate cause
- Iron replacement (not blood transfusion)
- Ferrous sulphate/fumarate 200mg tabs ( = 60mg elemental iron)
- Ferrous gluconate 300mg tabs ( = 36mg elemental iron)
- IV iron - can give 1g over 2-3 hours, Hb rises no quicker than oral replacement
What influences the thrombin clotting time?
- Depends on
- How much fibrinogen present in plasma
- How well that fibrinogen functions
- Will also be prolonged by
- Inhibitors of thrombin e.g. heparin, dabigatran
- FDPs (fibrin degradation products)
- Inhibitors of fibrin polymerisation (paraproteins)
Compare the severity of alpha and beta thalassaemia
Missing beta globin genes has more of an impact than missing alpha genes - only have two beta genes
What are the management options in splenic injury?
- Conservative - if stable, watch and wait
- Interventional radiology - block off bleeding vessel
- Surgery - tie off bleeding vessel, splenectomy
List the complications of a major haemorrhage
- Hypothermia
- Exposure to elements during trauma (?) + transfusion with clear fluid = dilatational coagulopathy
- Aggressively warmed - blood warmer, patient warmer, foil hat, monitor temperature, otherwise won’t clot
- Acidosis
- Blood loss means lower oxygen perfusion, tissue becomes hypoxic, more anaerobic respiration so more lactic acid production = lactic acidosis
- Monitor with blood gases
- Coagulopathy
- FFP, platelets, cryoprecipitate - liaise with blood bank
- Hypocalcaemia
- Blood loss = calcium loss
- Check ionised calcium on blood gas
- Replace - need calcium to clot
Explain latent iron deficiency
If the RES iron store is slightly low, the serum ferritin will fall but the Hb is initially maintained (not anaemic) Present in 20% of pre-menopausal women
What is the major role of RBC?
Gas transfer - CO2 removal from tissues to lungs, O2 delivery from lungs to tissues
Describe the use of imaging in the diagnosis of myeloma
- Historically plain X-rays used but may miss early lytic changes
- MRI is better at identification of lytic lesions
- May indicate incipient risk of fracture
- Skeletal survey of all long bones done
- Affects bones with active BM
- Plasma cells produce OAF –> alters bone turnover
- Multiple lytic lesions in skull and humerus
- Osteolytic lesions, fractures, pain and hypercalcaemia
- Pepper pot skull typical finding
- Spinal MRI
- Deformity more clear on MRI
- Flattened vertebrae, bulging backwards towards disc
- May present with spinal cord compression
Describe the phases which occur when you cut yourself
- Blood vessel damage
- Disruption of endothelium
- Exposure of
- Tissue factor
- Collagen
- Primary haemostasis
- Recruitment of platelets
- Secondary haemostasis
- Activation of coagulation factors
Occur simultaneously
Describe haemoglobin in sickle cell disease
HbS = 2 x alpha chains, 2 x beta chains (sickle)
Continuously polymerised/depolymerised, rate of polymerisation depends on:
- Deoxygenation rate - low oxygen = polymerisation (cells sickle)
- HbF - high levels of HbF protect against sickling Hb concentration
Describe the immune complications associated with chronic lymphoblastic anaemia
- Autoimmune haemolytic anaemia - 5-10%
- Autoimmune thrombocytopenia - <5%
- At presentation, precipitated by treatment
- Treat with steroids, treat CLL
- Infection due to:
- Hypogammaglobulinaemia - not enough gamma globulins produced, low antibodies
- Cell mediated immunity impaired
- T lymphopenia
- Neutropenia
- Defects in complement activation
- Pulmonary infection common
- Bacteria, encapsulated organisms
- Viral
- Pneumocytosis
- Fungi
- As likely to die from infection as from CLL
How is the indirect Coombs test carried out?
Plasma mixed with red cells from unit of blood to be transfused, if antibodies are present they will bind to red cells in transfused blood - look for antibodies in plasma/on RBC
Compare LMWH and UFH
- LMWH have superior pharmacokinetic profile allowing predictable dose response
- LMWH have safer side effect profile
- LMWH clinical efficacy at least equal to UFH
- LMWH have higher drug costs but lower consumable costs and do not require monitoring
- LMWH can be used in out-patients
How are lymphomas staged?
Ann-Arbor classification system
- Stage I: single lymph node group
- Stage II: More than one lymph node group same side of the diaphragm
- Stage III: lymph node groups both sides of the diaphragm (includes spleen)
- Stage IV: extranodal involvement e.g. liver, bone marrow (spread via blood)
A or B added after to signify absence or presence of B symptoms
Early stage: 1 or 2A (no B symptoms)
Advanced stage: 2B or 3/4
Describe the mechanism of action of GPIIb/IIIa antagonsits
- Monoclonal antibodies antagonise IIb/IIIa receptor
- Reduced platelet aggregation
- Reduced binding of fibrinogen
How is classic Hodgkin’s lymphoma treated?
- Very effective
- High cure rates (>90% in early stage, 75-85% in advanced stages)
- Early stage - usually combined modality Rx i.e. chemotherapy followed by radiotherapy
- Advanced stage - chemotherapy
- Late effects important e.g. malignancy, cardiac, pulmonary, fertility, endocrine
- Balance between effective treatment of disease against risk of effects for given individual
- Chemotherapy = ABVD
What can cause B12 deficiency?
- Pernicious anaemia
- Low B12 in plasma (normal in tissues) - pregnancy, hormonal contraceptives, metformin, PPIs
- Gastrectomy/achlorhydria - no parietal cells
- Dietary
- Terminal ileum problem - Crohn’s, resection
Describe immunochemotherapy used to treat advanced stage follicular lymphoma
Rituximab (anti-CD20 monoclonal Ab) + chemotherapy (CVP or CHOP or bendamustine)
Describe the grading of splenic injuries
List the types of stem cell transplant
- Autologous transplant (autograft) - patients own blood cells
- Allogenic transplant (‘allograft’) - any transplant in which stem cells come from a donor
To what extent can bone marrow compensate for reduced RBC lifespan in haemolytic conditions?
- Normal lifespan is 120 days
- If reduced down to 20 days can compensate by producing more RBC, any less and anaemia will develop
- Lifespan 120 days - Hb normal
- Lifespan 20-100 days - Hb normal, raised reticulocytes, raised unconjugated bilirubin = compensated haemolytic state
- Lifespan <20 days - reduced Hb, raised reticulocytes, raised bilirubin, hypersplenism = haemolytic anaemia
Describe the AVBD chemotherapy regimen
A - Adriamycin (doxorubicin)
B - Bleomycin
V - Vinblastine
D - Dacarbazine
Given on days 1 and 15 of 28 day cycle
What is the treatment for hereditary spherocytosis?
If required - splenectomy
- Destroys RBC so removal restores RBC lifespan to normal but at increased risk of infection from encapsulated organisms
How does leukaemogenesis occur?
- Normal HCS (or myeloid/lymphoid cell) acquires changes through a multistep process to become leukaemic cell - requires 2 genetic hits to develop leukaemia
- Dysregulation of cell growth and differentiation - associations with mutations
- Proliferation of the leukaemic clone, differentiation blocked at an early stage (immature leukaemic blast cell population)
Give examples of causes of DIC
- Sepsis
- Malignancy
- Massive haemorrhage
- Severe trauma
- Pregnancy complications e.g. pre-eclampsia, placental abruption, amniotic fluid embolism
How is the fate of a haematopoietic controlled?
Complex interaction between micro-environment signals (the niche) and internal cues - Wnt, notch and hedgehog signalling are important for controlling
List the different forms of graft vs host disease
Acute GvHD - within first 100 days of transplant Chronic GvHD - after first 100 days of transplant
How much dietary iron is required daily?
- 1-2mg/day
- Western diet - 15-20mg/day so nutritional IDA in adults v rare
What causes haemophilia A?
- Classical haemophilia
- Factor VIII deficiency
- Severe <1iu/dl (spontaneous bleeds)
- Moderate 2-5iu/dl (minor trauma bleeds)
- Mild 6-40iu/dl (surgical bleeding)
- X-linked inheritance
List the abnormalities seen in Fanconi anaemia
- Microphthalmia
- GU malformations
- GI malformations
- Mental retardation
- Hearing loss
- CNS e.g. hydrocephalus
- Short stature
- Digit abnormalities e.g. absent thumbs
- Cafe au lait macules
Define thrombocytopenia
Reduction in the number of platelets
Describe the mechanism of action of kinases
- Bind to plasminogen - releases plasmin, enhanced breakdown of fibrin
- Activity on both clot bound and free plasminogen
- Causes both fibrinolysis and systemic fibrinogenolysis
- Significant bleeding risk
Describe menorrhagia
>80ml blood/period 20ml blood/period normal
What is the disadvantage of donor lymphocyte infusion?
1/3 of DLI recipients will develop graft vs host disease (donor cells attack the host tissue), unless measures are taken to reduce the risk
What are the requirements for samples used for coagulation tests?
- Pre-analytical
- Citrate sample (9:1 ratio)
- Chelates all calcium
- Centrifugation
- Separates cellular component
- Platelet poor plasma (PPP)
What is the effect of B12/folate deficiency on blood cells?
- Macrocytic anaemia
- Many large immature and dysfunctional red cells seen in bone marrow = megaloblasts
- Hypersegmented neutrophils - 5-7 lobes
- Erythroblasts destroyed in BM, v few reticulocytes but BM hypercellular
List the pros and cons of DOACS vs warfarin
Warfarin
- Slow onset slow offset - results in smooth anticoagulation
DOACs
- Rapid onset and offset - anti-coagulated within 3h of 1st dose
Warfarin
- Requires very individualised dosing
DOACs
- May require dose adjustment based on CrCl
Warfarin
- Requires INR monitoring
DOACs
- Requires annual review
Warfarin
- Many drug, food and alcohol interactions
DOACs
- Few drug and no food/alcohol interactions
Warfarin
- Renal impairment may increase bleed risk
DOACs
- Renal impairment may be a contra-indication
Warfarin
- Rare side effects other than bleeding
DOACs
- More minor side effects
Warfarin
- Rapid reversal with PCC and Vitamin K
DOACs
- Currently no rapid reversing agent
Describe the mechanism of action of dipyridamole
- Increased platelet concentration of cAMP
- Increased cAMP leads to decreased platelet responsiveness to ADP
- Reduced platelet aggregation
List the types of antithrombotic agents
- Anticoagulants
- Inhibit one or several components of coagulation cascade
- Fibrinolytic agents
- Enhance lysis (breakdown) of fibrin clot
- Anti-platelet agent
- Inhibit platelet activation or aggregation
Describe the management of acquired warm type haemolytic anaemia
- Corticosteroids
- Mainstay of management
- Usually Prednisolone, initially high dosage range of 60-100mg per day, subsequently reduced
- Haemolysis should be dramatically reduced in 80% of patients within 3 weeks
- Blood transfusion
- Transfusion of packed red cells may be required dependent on patients symptoms
- Folic acid
- Demand for RBC so high that folic acid may be compromised and supplementation may be required in severe cases
- Splenectomy
- Treatment of choice in patients whose anaemia is refractory to prednisolone, or those who require long term high dose therapy to suppress the haemolytic state
- Such patients liable to develop the serious complications of steroid therapy
Describe the typical natural history of multiple myeloma
Define pernicious anaemia
Autoimmune disease of gastric parietal cells - gastric parietal cell autoantibodies in 95%, intrinsic factor autoantibodies in 50%
Associated w/ other autoimmune diseases e.g. hypothyroidism
How is the coagulation cascade regulated?
- Antithrombin inhibits VIIa, XIa, IXa, Xa, IIa
- Tissue factor pathway inhibitor inhibits VII + TF –> VIIa
- Protein S and APC (activated protein C) inhibit Va and VIII
Define a major haemorrhage
- Loss of more than one blood volume within 24 hours (around 70mL/kg, >5 litres in a 70kg adult)
- 50% of total blood volume lost in less than 3 hours
- Bleeding in excess of 150mL/minute
How is cold AIHA treated?
Self limiting mycoplasma, idiopathic - keep warm
Describe the normal saturation of transferrin with iron
Normally 30% iron saturated with iron
What can cause intravascular haemolysis?
- Can occur by mechanical trauma to red cell - red cell fragmentation syndromes i.e. RBC breakdown by defective mechanical heart valves (RBC fragmentation also seen in haemolytic uraemic syndrome and microangiopathic haemolytic anaemia
- Can follow ABO incompatible blood transfusion (anti-A and anti-B are IgM antibodies)
- Can also be due to malaria, cold (IgM) autoantibodies - cause RBC to agglutinate on blood film
- Difficult to treat - advised to keep warm (antibody only fixes to RBCs in colder parts of the body i.e. cold hands etc.)
Define beta thalassaemia
Missing Beta globin genes - should have two
How does plasma cell myeloma present?
- Majority of new cases have non-specific symptoms
- Backache or rib pain (60%)
- Fatigue
- Symptoms of hypercalcaemia (30%)
- Recurrent infections - chest
- Renal impairment (25-30%)
- Average GP will only see 1-2 cases in whole career
- Diagnosis often unavoidably delayed with patients being referred via a variety of specialists
List the types of alpha thalassaemia
- Normally 4 alpha globin genes - 2 from mother, 2 from father
- Can be missing -
- One alpha gene from one parent = alpha+ thalassaemia trait
- One alpha gene from each parent = homozygous alpha+ thalassaemia trait
- Two alpha genes from one parent = alpha0 thalassaemia trait
- Two alpha genes from one parent, one from the other = HbH disease
- Two alpha genes missing from each parent (no remaining genes) = alpha thalassaemia major
How can disorders of RBC enzymes cause haemolytic anaemia?
- Pyruvate kinase (glycolysis) deficiency anaemia - chronic extravascular haemolytic anemia due to ATP depletion, autosomal recessive
- Glucose-6-phosphate dehydrogenase (pentose phosphate pathway) deficiency - acute episodic intravascular haemolysis, X-linked recessive, acute haemolysis from oxidative stress (Favism, drugs e.g. anti-malarials, sulphonamides)
What evidence is there to support the concept of clonality in haematological conditions?
- Almost all lymphoproliferative disorders and some AMLs carry a unique rearrangement of either an immunoglobulin or TcR gene (whereas non-malignant lymphoid proliferations are polyclonal)
- X chromosome inactivation studies in women with leukaemia show the clonal proliferation carrier either an active maternal or paternal X chromosome (limited utility - many women develop skewed X inactivation with age)
- Acquired cytogenic or molecular changes that arise during development of a malignancy e.g. Philadelphia translocation in CML
How do erythroblasts use iron?
Iron converted to haem in erythroblast mitochondria using enzyme ALA-S2, extra stored as ferritin
How is iron transported in plasma?
Transferrin - glycoprotein molecule with 2 iron binding domains Travels and binds to cells with transferrin receptors, delivers iron to all tissues, erythroblasts, hepatocytes, muscle etc
Define thalassaemia
Haemoglobinopathy due to relative lack of globin genes - alpha or beta
List the types of congenital haemolytic anaemias
- Abnormalities of RBC membrane
- Haemoglobinopathies
- Abnormalities of RBC enzymes
List the characteristics of myeloproliferative diseases
- Clonal blood disorders
- JAK2 mutation prevalent
- Characterised by ‘effective’ haemopoiesis
- Too many platelets - essential thrombocytopaenia
- Too many red cells (+ platelets + WC) - polycythaemia vera or primary polycythaemia (same thing)
- Too much fibrous tissue (+ platelets + WC) - myelofibrosis
What are the requirements for normal erythropoiesis?
- Drive for erythropoiesis - erythropoietin produced by interstitial cells of kidney in response to tissue hypoxia
- Genes required for erythropoiesis
- Haematinics - iron, B12, folate, minerals
- Functioning bone marrow - no increased loss/destruction of red cells
What effect does G-CSF have on haematopoietic stem cells?
Mobilises stem cells peripherally using growth factors - used for stem cell transplant
Compare myeloma and monoclonal gammopathy of undetermined significance (MGUS)
- Difficult to differentiate
- MGUS = common age related condition, plasma cell dyscrasia
- Plasma cells or other antibody producing cells secrete a myeloma protein (abnormal antibody) into the blood/urine
- Accumulation of bone marrow plasma cells derived from a single abnormal clone
- Resembles multiple myeloma and similar diseases but lower levels of antibodies and lower levels of plasma cells in bone marrow
- MGUS can lead to myeloma - monitoring needed
- MGUS don’t experience any signs or symptoms usually
Which blood cells are derived from lymphoid stem cells?
B/T lymphocytes, NK cells
Who is the ideal VUD and why?
Young male donors are preferred - less exposure to antigens compared with women due to childbirth
Describe the molecular biology of Fanconi anaemia
- Fanconi anaemia mutations cause
- Up-regulation of pathways e.g. MAPKs –> TNF-alpha (inflammatory cytokine)
- Altered DNA damage responses (FA-BRCA pathway)
- Abnormal oxidative stress response
- Other aberrations e.g. defective telomere maintenance
- environmental factors (e.g. sunlight, smoking, infections, chemotherapy) = Genomic instability, altered cell checkpoints and survival - cells survive damage and go on to become malignant
What usually causes IDA in males/post-menopausal women?
Due to GI blood loss until proven otherwise
List the presenting features of chronic lymphocytic leukaemia
- None
- Lethargy, night sweats, weight loss
- Symptoms of anaemia
- Lymphadenopathy
- Infection
List causes of macrocytosis other than folate/B12 deficiency
- Reticulocytosis - 20% bigger than average mature red cell
- Cell wall abnormality (lipids) - alcohol, liver disease, hypothyroidism (poorly understood)
- With anaemia - bone marrow failure syndromes e.g. myelodysplastic syndromes
What is expressed by B cells in B cell lymphoma that can be the target for treatment?
B cells express CD20 antigen, target for treatment of B cell lymphoma with the monoclonal antibody Rituximab
Describe the process of a splenectomy
- Trauma laparotomy for bleed into abdomen -
- Incision from xiphoid sternum –> pubic symphysis
- Usually find several litres of blood + clots - remove
- Blood/clots have been acting as tamponade stopping blood flow, need to pack abdomen with highly absorbent swabs to create tamponade
- Swabs into paracolic gutters, pelvis, above spleen and liver
- Remove packs from area of least concern to area of most concern to find source of bleeding, full laparotomy circuit to find injuries that the CT may have missed
- Spleen is end on organ - on a single vascular pedicle - so is relatively easy to detach and remove
- Splenic artery from coeliac plexus, passes behind pancreas
- Splenic vein back to join with the SMV forming the HPV
- Endoscopic stapling gun can be used
Define haemolytic anaemia
Anaemia related to reduced RBC lifespan, no blood loss, no haematinic deficiency
Why is there often a small residual mass after diffuse B-cell lymphoma treatment?
Fibrosis
Describe the treatment of sickle cell disease
- Prevent crises - hydration, analgesia, early intervention, prophylactic vaccination and antibiotics (hyposplenic infections), folic acid (BM inactive/ineffective)
- Prompt management of crises - oxygen, fluids, analgesia, antibiotics, specialist care, transfusion/red cell exchange - reduce amount of HbS
- Bone marrow transplantation
How can bone marrow be collected for investigation?
Aspiration - sample of bone marrow taken from back of iliac crest using hollow needle, under local anaesthetic - liquid component of bone marrow Trephine - solid core of bone
Describe the presentation of Burkitt lymphoma
- Usually short history, marked B symptoms, rapidly growing tumours with massive tumour bulk
- Most cases present with extra-nodal disease
- Jaws and facial bone (endemic BL in African children)
- Ileocaecal region of GIT - often primary site
- Ovaries
- Kidneys
- Breast
- Lymph nodes and bone marrow more frequently affected in immunosuppression-associated BL
- CNS involvement at presentation or relapse is common in all types - brain, meninges or both
What is alcohol induced pain in lymph nodes a symptom of?
Rare feature of Hodgkin’s lymphoma
How are PET/CT scans used in the staging of lymphoma?
PET/CT scan with FDG tracer - taken up in areas that are metabolically active e.g. brain, heart, bladder
What is clonal haemopoiesis?
Common age related phenomenon in which HSC or other early blood progenitors contribute to the formation of genetically distinct subpopulations of blood cells (derived from single founding cell)
What causes warm AIHA?
Idiopathic in 30%, other autoimmune disease, lymphoproliferative disorder (NHL, CLL), drug induced
Where are haematopoietic stem cells found?
Bone marrow, peripheral blood after treatment with G-CSF, umbilical cord blood
How much iron is usually lost in pregnancy?
500mg/baby
How is myelodysplastic disorder managed?
Incurable (other than with SCT, <65 years), for rest supportive care, consider drug therapy e.g. azacitidine
Describe the process of an umbilical cord blood stem cell transplant
Blood stem cells collected from umbilical cord and placenta Cells tissue typed and frozen and liquid nitrogen in cord blood banks for future use
Where are most transferrin receptors found?
80% on developing RBCs - erythroblasts
Define anaemia
Reduction in the number of RBC
How do patients with B12/folate present?
- Symptoms of anaemia/cytopenia - tired (macrocytic RBCs/megaloblastic marrow), easy bruising (thrombocytopenia - rare), beefy red tongue (B12 deficiency)
- Mild jaundice - lemon yellow tint, due to ineffective erythropoiesis in marrow
- Neurological problems - nerve disturbance as a result of B12 deficiency (subacute combined degeneration of cord)
List the causes of IDA
- Dietary - premature neonates, adolescent females, v uncommon in adults
- Malabsorption
- Blood loss
Describe beta thalassaemia major
- Missing both beta globin genes - unable to make adult haemoglobin
- Autosomal recessive condition
- Causes bone changes as bone marrow expands to try to compensate for missing beta globin
Describe the stratification of essential thrombocytopenia into risk groups for treatment
- Low risk = age <40 with no risk features
- Intermediate risk = aged 40-60 with no high risk features
- High risk = aged >60, one or more high risk features - platelets >1500, previous thrombosis or thrombotic risk factors e.g. diabetes or hypertension
What is seen on electrophoresis in myeloma?
Monoclonal band
Describe abnormal destruction of red cells in haemolytic anaemia
- Haemolysis = increased in RBC destruction
- Bone marrow has ability to increase red cell production 6-8 x - RBC lifespan has to be reduced to <15-20 days before anaemia develops
- Mechanism of destruction in haemolytic anaemia by two pathways:
- Intravascular - destruction of red cells directly in the circulation
- Extravascular - destruction of red cells in the RES of the spleen, liver and bone marrow
What are the indications for heparins?
- Provides immediate but short acting anticoagulant effect
- Acute DVT or PE (subcutaneous LMWH)
- During cardiac bypass surgery (IV UFH)
- Acute coronary syndromes (along with anti-platelet agents)
- Medium term after VTE in cancer patients
- Prophylaxis against VTE
- Medical and post-op patients (low dose LMWH)
- Obstetric patients