Haemotology Flashcards
Where are the RBCs produced throughout life?
Yolk sac (1 month)
Liver (2-birth)
All bone marrow (1-10yrs)
Mainly axial marrow (vertebra/pelvis) (10-death)
3 important haematopoietic growth production?
G-CSF: - granulocyte colony stimulating factor EPO: - erythropoietin produced in kidney - if reduced, leads to hypoxia TPO: - thrombopoietin produced in liver - if reduced, leads to thrombocytopenia
Full blood count
I. RBC 1. Hb concentration 2. Haemotocrit (ratio of red cell to total) 3. cell number (RBC) 4. cell size (mean cell volume, MCV) A. microcytic <80fl (iron deficiency) B. normocytic 80-100 fl C. macrocytic >100 fl (B12/folate deficiency) 5. MHC/MCHC (amount of Hb/RBC)
II. platelets
III. white blood cells (number &differentiation)
Reticulocyte count
- what is it?
- In a patient with anaemia:
a. why would it increase?
b. why would it decrease?
- number of young, recently released from bone marrow RBC
2. a. normal response: to replenish the loss due to haemolysis or bleeding
2. b. there is a problem with bone marrow production of RBC
Peripheral blood film
what is it?
drop of blood under microscope assessed for
- number
- size
- colour
- morphology
Define:
- -cythaemia
- -cytosis
- -cytopenia, 2 things that can lead to this?
- reactive cause vs neoplastic
- increased number
- increased number
- reduced number
- production impaired or survival (haemolysis, bleeding)
- 3 common ones: Anaemia, thrombocytopenia, neutropenia - reactive cause can be due to anything (inflam, infection, autoimmune, etc) but neoplastic
Reactive concitions describing increased number of blood cells in :
I. lymphoid
II. myeloid
I. lymphoid - lymphocytosis - polycolonal gammaglobulinaemia: === normal kappa:lambada ratio === due to infection, inflammation, malignancy
II. myeloid
- thrombocytosis
- neutrophilia
- polycythaemia
Polycythaemia
- def
- various causes
- Increased Hb, raised Hct
- I. Relative
- due to reduced plasma volume, no change in absolute RBC mass, proportionate increase
- dehydration, diuretics, alcohol
II. absolute
IIa. Primary :
- ruba vera
- JAK2 mutated, EPO suppressed
IIb. Secondary:
- hyoxia, smoking, altitude, tumours
- JAK2 unmutated, EPO increased
Thrombocytosis causes
1. reactive • Trauma (e.g. by surgeon) • Infection • Inflammation • Non Haematological Malignancy • Iron deficiency • Splenectomy
- Clonal: Myeloproliferative disorders (MPN)
- Spurious (FBC machine counts something else as platelets)
Leukocytosis
Mainly neutrophilia and lymphocytosis
Common causes: 1. Reactive • Trauma (e.g. by surgeon) • Smoking • Infection • Inflammation • Steroids • Non haematological Malignancy • Splenectomy 2. Clonal (lymphoproliferative, myeloproliferative, acute or chronic)
Causes of lymphadonepathy
- Infection (viral e.g. HIV/EBV , bacterial e.g TB)
- Non haematological cancer (e.g. Ca)
- Inflammatory (e.g. sarcoid, SLE)
- Lymphoproliferative neoplasms
Symptoms of myeloma?
CRABI” acronym C- Hypercalcaemia R- Renal dysfunction A- Anaemia B- Bone – lytic lesions, fractures, osteoporosis I- Infection
2 O/E signs of thrombocytopenia?
- petechiae (pin prick bruises)
2. Ecchymoses (wide spread bruises)
Neutropenia
- epi
- increased risk of ?
- africans have lower levels of neutrophils than others
2. bacterial infection (not parasite or viral infection)
2 types of Acute leukaemia?
- acute myeloid leukaemia (AML)
2. acute lymphoblastic leukaemia (ALL)
Leukaemia
- How it leads to anaemia/immune suppression?
- Sx
- Clonal proliferation of malignant blood cells derived from primitive haemopoietic stem cells in bone marrow.
- Uncontrolled expansion of hypofunctional cells in blood, bone marrow and other organs leads to suppression of normal haematopoiesis and immunity
- Main clinical problems include anaemia, bleeding and susceptibility to infection.
- Also lymphadenopathy, hepatosplenomegaly, and skin and CNS infiltration
Leukaemia:
- Endogenous RFs
- Exogenous RFs
- Endogenous factors
- Chromosome fragility syndromes
- Downs syndrome
- Hereditary immune deficiency
- Familial - Exogenous factors
- Radiation
- Chemotherapy
- Benzene
- Viral infection
- Acquired immune deficiency
Acute Myeloblastic Leukaemia (AML)
- Epi?
- Ix
- Mx
- complication of treatment
- Commoner in adults, Incidence 1:10,000 annually, Increased frequency with age (median >70 yr)
2. I. FBC: - low Hb and platelet count - WBC usually 20 – 100 x 109/L with blast cells visible on the peripheral blood film. - WBC >50 = high risk II. Bone marrow: - blasts > 20% of nucleated cells III. Flow cytometry: - CD13+, CD33+ helpful to confirm AML. IV. Cytogenetics: - good prognostics: ------t(15;17), ------t(8;21), ------inv16 . - poor prognostic markers: ------Monosomy 7, ------abnormalities on chromosome 5, ------chromosome 1 ------complex cytogenetics (>5 abnormalities)
- I. Combination chemotherapy
- cytosine arabinoside
- daunorubicin.
- Retinoic acid/arsenic trioxide used in acute promyelocytic leukaemia.
- High dose ara-C important in optimising outcome
- 3-4 cycles of therapy given 4 – 6 weekly.
- Treatment induces profound marrow suppression, prolonged pancytopenia
II. Supportive care
- Transfusion of red cells and platelets.
- Antiseptic mouthwashes, clean diet, oral prophylactic anti-fungal agents and antibiotics.
4. • Infection: mainly bacterial and fungal • Bleeding (if in CNS can be fatal) • Debility, profound weight loss • Social: inpatient for most of 6 months, loss of employment, stress on family
5.
- Overall complete remission rate: 85%
- Overall survival: 45-50% cured with chemotherapy alone
Acute Lymphoblastic Leukaemia (ALL)
- def
- age
- how to differentiate from AML?
- Ix?
- treatment
- prognosis
- Primitive lymphoblasts infiltrate bone marrow and circulate in blood, infiltrate liver and spleen
- peak age 2 – 10 years. Another peak >60 years
- Commonly causes severe bone pain, sweats
- As for AML.
I. Lumbar puncture important to determine if there is evidence of CNS disease (usually done when peripheral blasts cleared)
II. Flow cytometry may show blasts of B cell (CD10+, CD19+) or T cell lineage (20%).
III. Cytogenetics:
- Philadelphia chromosome t(9;22) seen in 20-25 % of adults. Poor prognostic marker but specific therapy with tyrosine kinase inhibitors.
- Other poor prognostic lesions
- —–t(4;11),
- —–t(8;14) ,
- —–hypodiploidy
- —–complex cytogenetics
5. I. Chemotherapy with complex combinations of cytotoxic drugs eg - steroids, - vincristine, - daunorubicin, - asparaginase.
Phases of therapy
a. Induction: 2 months. Remission induction
b. Consolidation: 4 months intensive chemotherapy and CNS prophylaxis.
c. Maintenance: 2 years less intense therapy; mainly oral cytotoxic drugs with IV pulses of VCR
- > 85% cure in childhood ALL
50% cure rate in adults who have intensive treatment on national trials.
Minimum residual disease
- Leukaemic clone can be identifed by DNA fingerprinting and accurately measured using Q PCR. Sensitive (1 in 10,000 cells or better)
- Response to therapy after 2 cycles of therapy may override other pretreatment prognostic factors
- MRD used to decide treatment in children and adults
Bone marrow transplant
How does it work?
Major complications?
- Allows use of higher (3-10x standard) doses of chemotherapy or chemoradiotherapy, kill more leukaemic cells
- The transplanted stem cells give the recipient a new immune system that includes T cells capable of recognising leukaemia cells and killing them via a graft versus leukaemia effect
Major complications • Relapse • Graft versus host disease • Extramedullary toxicity • Infection • Rejection • Long term: infertility, second cancers
Neutropenic Sepsis
- what is it?
- Sx?
- Ix
- Mx
- The most common medical emergency that results from the treatment of leukaemia and bone marrow transplantation
• T >38C or patient looks unwell: culture and start broad spectrum antibiotics within 1 hour
3.
I. Absolute neutrophil count <0.5, worse if <0.2 or actually 0
II. Peripheral and line cultures, possibly CXR, MSU. Look for foci of infection.
III. CRP helpful to monitor response, may not be elevated on day 1
- I. culture and start broad spectrum antibiotics within 1 hour
II. Treat hypotension, organ dysfunction eg hypoxia.
Blood donations tested for?
ABO group RhD type HIV 1+2 antibodies Hepatitis BsAg + PCR Hepatitis C antibody and RNA PCR Syphilis antibody HTLV antibody
Processing of blood donations?
- Leucocyte depletion
- centrifuged:
- red cells
- platelets
- Plasma:
====Fresh frozen plasma
====cryoprecipitate - Platelets sampled for
bacterial testing - Special processes (to
order):
- irradiation,
- washing,
- hyperconcentration
Red cells in blood donations
- shelf life?
- storage?
- how much time once out of fridge
- uses
- 35 day shelf life
- at 4 degrees
- transfuse < 4 h after removing from fridge
- Uses
- Blood loss
- Anaemia
Platelet concentrates in blood donations
- 2 methods of getting them?
- shelf time?
- storage
- uses?
1. I. Pool 4-6 donors blood II. Apheresis - single donor 2. max for 7 days 3. Storage: 22oC 4. Uses: - Thrombocytopenia -Bleeding with low plt -Preventing bleeding -very low plt -before procedures
Fresh frozen component in blood donations
- storage
- shelf-time
- use
- special processing
- Plasma frozen to -30oC
- 2 yr storage
- For clotting factor replacement if bleeding
4.
I.Viral inactivation
-Methylene Blue
II. Solvent detergent
treatment (Octaplas)
Cryoprecipitate
- how is it formed?
- use
- Precipitate that forms
when thawing FFP - Fibrinogen replacement
When to give blood transfusion in anaemia?
If below Hb < 7g/dL
acute haemolytic transfusion reaction
1. Time period?
2. types
3.
- at any time up to 24 hours following a
transfusion - I. haemolytic reactions,
II. transfusion-related acute lung injury (TRALI),
III. transfusion-associated circulatory overload (TACO),
IV. transfusion-associated dyspnoea (TAD) V. those due to bacterial contamination of
the component - Fever, renal failure
Donor PLASMA compatibility: Platelets, FFP & cryoprecipitate
A receives from A or AB
B receives from B or AB
O receives from any
AB receives from AB
Blood clotting pathway (haemostasis)
- Collagen and tissue factor exposed
- Von Willebrand Factor binds collagen
- Platelets adhere to vWF-collagen
- Platelets activate and aggregate
- TF initiates rapid thrombin generation on activated platelets (by causing release of Proteases (FVII, FX, FIX, FXI) and Co-factors (FVIII and FV))
- Thrombin converts fibrinogen to fibrin and
completes platelet activation - Stable fibrin-platelet clot is formed
3 regulations of haemostasis
- vWF activity is regulated by ADAMTS 13
- Thrombin is regulated by Antithrombin and Activated protein C
- Fibrin cleaved by Plasmin into fibrin degradation products (D-dimer)
2 types of clinical disorders of haemostasis?
Compare their bleeding pattern?
Their main complication?
Timing of bleeds?
- Primary haemostasis disorders
- defect: Platelets, VWF, vessel wall
- mucocutaneous bleeding eg epistaxis, purpura
- immediate bleeding - Coagulation pathway disorders
- defect: Coagulation factors and fibrinogen
- deep tissue bleeding (joints)
- delayed bleeding (weak clot forms and breaks, followed by secondary bleeding)
Both can cause GI/CNS bleeds
Laboratory investigations of bleeding?
1. Platelet count + blood film Indicates platelet number (not function) 2. Coagulation screen I. Prothrombin time (PT) II. Activated partial thromboplastin time (aPTT) Indicate function of coagulation pathway
Principle of Prothrombin time (PT) and Activated partial thromboplastin time (aPTT)
What do each detect?
- Venous blood anticoagulated in 0.9% citrate to remove Calcium and stop clotting
- centrifuge plasma
- Add coagulation ‘activator’: includes calcium
- Incubate at 37 C
- Time to fibrin clot formation
PT:
• ‘Thromboplastin’ activator
• Detects abnormal FVII, (extrinsic pathway)
FX, FV, FII, Fibrinogen (common pathway)
aPTT
• ‘Contact activator’
• Detects abnormal FVIII, FIX, FXI (intrinsic factors)
FX, FV, FII, Fibrinogen (common pathway)
Haemophillia
- 2 types
- defects in
- genetics?
- Sx
- Mx
- A & B
- Defect in F8 gene causing reduced FVIII (haemophilia A)
Defect in F9 gene causing reduced FIX (haemophilia B) - Sex-linked recessive inheritance (on X chromosome)
- Coagulation pathway disorder
I. Mild or severe bleeding depending on factor level
II. Soft tissue and joint bleeds
III. Life-threatening CNS or GI tract bleeds
IV. Chronic arthropathy (bleeding in joint leads to inflammation)
V. Treatment acquired HCV and HIV - Recombinant factor concentrate (synthetic factor 8 & 9)
- prophylaxis every 2-3 weeks
Von Willebrand disease
- normal role of vwf?
- Mild and severe Sx?
- Ix?
- Mx
- VWF mediates PLT adhesion to collagen
- stabilises coagulation Factor VIII in the plasma
- MILD VWD:
- Epistaxis, easy bruising and traumatic skin bleeding
- Defective primary haemostasis
SEVERE VWD:
- Additional coagulation pathway
- defect due to low FVIII - I. First line tests
• Platelet count normal
• Long aPTT in moderate or severe VWD (when FVIII level is low)
II. Second line tests
• reduced plasma VWF activity
• reduced plasma FVIII activity - I. Tranexamic acid
Reduces clot break-down (antifibrinolytic)
II. DDAVP/Desmopressin
- Releases endogenous FVIII and VWF
- only works once, temporary release
III. VWF/FVIII concentrate
Acquired bleeding disorders
1. Abnormal synthesis • Liver disease* • Vitamin K deficiency (coagulation factors II, VII, IX, X) • Warfarin* 2. Abnormal function • Heparin and direct acting oral anticoagulants* • Renal failure (platelet dysfunction) • Anti-platelet drugs 3. Dilution • Massive transfusion • Cardiopulmonary bypass 4. Consumption • Disseminated intravascular coagulation* • Thrombocytopenia in sepsis