Haematology Flashcards
Indications for red cell transfusion
((transfusion of blood products in dangerous and must be justified as essential to prevent major morbidity or mortality))
- To correct severe acute anaemia which may cause organ damage
- To improve QoL in a patient with uncorrectable anaemia
- To prepare a pt. for surgery/ speed up recovery
- To reverse damage caused by a patients own red cells (e.g. sickle cell disease)
Indications for platelet transfusion
((transfusion of blood products in dangerous and must be justified as essential to prevent major morbidity or mortality))
Massive haemorrhage
Dilutional thrombocytopenia after massive transfusion
Bone marrow failure/ abnormalities of platelet function
Prophylaxis for surgery (esp. cardiopulmonary bypass)
DIC if bleeding
((try not to cross blood groups but you can))
Effects of development of maternal anti-D antibodies on an RhD+ baby
Anti-D is an IgG so crosses the placenta
Reacts with baby’s RBCs
Baby develops cardiac failure and dies in utero or shortly after
SPIKES model for delivering bad news
S-etting and listening skills (e.g. private place)
P-atient’s perspective (what do they already know?)
I-indication (warning shot)
K-nowledge (chunking + checking)
E-xplore emotions and empathise
S-trategy and summary
Thrombus =
“clot arising in the wrong place”
Thromboembolism =
“movement of clot along a vessel”
Virchow’s Triad
Stasis
(bed rest, travel)
Hypercoagulability
(high oestrogen (pregnancy, OCP, HRT), trauma)
Vessel damage
(atherosclerosis)
((imbalance of any one can lead to thrombosis))
Things to ask about when investigating a potential bleeding disorder
POST SURGICAL BLEEDING Bruising Epistaxis Menorrhagia Post trauma bleeding (post-partum haemorrhage)
And to establish whether congenital or acquired…
- previous episodes?
- age at first event?
- previous surgical challenges
- FH
A platelet type pattern of bleeding (i.e. bleeding caused by failure of primary haemostasis)
Mucosal Epistaxis Menorrhagia GI Post-surgery Purpura/ petichiae (don't blanche!)
(e.g. von Willebrand Disease, Thrombocytopenia)
A coagulation factor pattern of bleeding
Artigular
Muscle haematoma
CNS
Indications for transfusions of different blood products
Red cells - anaemia
Platelets - thrombocytopenia
FFP - low coagulation factors
Cryoprecipitate - low fibrinogen
Aim to keep a patient’s haemoglobin level above…
70
90 - 100 if cardiac impairment
The process of recovering blood lost during surgery and re-infusing it into the patient is called
IOCS (intra-operative cell salvage)
immediate action for a patient with major haemorrhage
Call 2222
State: “major haemorrhage protocol activation” + location of patient
((you will then be passed to blood bank))
Indications for FFP use
((transfusion of blood products in dangerous and must be justified as essential to prevent major morbidity or mortality))
Replacement of coagulation factors (due to major haemorrhage)
DIC if bleeding
Thrombotic Thrombocytopenic Purpura (TTP)
Replacement of coagulation factor deficiencies where factor concentrate unavailable
cryoprecipitate contains
FIBRINOGEN
coagulation factors F8, F13
vWF
Indications for use of cryoprecipitate
((transfusion of blood products in dangerous and must be justified as essential to prevent major morbidity or mortality))
Hypofibrinogenaemia secondary to massive transfusion
DIC with bleeding and fibrinogen <1g/L
Bleeding associated with thrombolytic therapy causing hypofibrinogenaemia
Renal or liver failure and abnormal bleeding
Inherited hypofibrinogenaemia
what units are used to prescribe a blood transfusion?
“units”
1 unit = from 1 donation (separated)
the set of surveillance procedures covering the entire blood transfusion chain, from the donation and processing of blood and its components, through to their provision and transfusion to patients, and including their follow-up
Haemovigilance
pyrexia following a transfusion may be due to a….
+ treatment
febrile non-hemolytic transfusion reaction (FNHTR)
management: antipyretic
((usually another underlying cause))
Urticaria following a transfusion may be due to a….
+ treatment
Causes:
- mild allergic reaction
- anaphylaxis
management: antihistamine, adrenaline
Dyspnoea following a transfusion may be due to a….
+ treatment
Transfusion associated circulatory overload (TACO)
Transfusion related acute lung injury (TRALI)
Anaphylaxis
Management: O2, diuretic, ventilation, adrenaline
Shock following a transfusion may be due to a….
+ treatment
Incorrect blood component transfused (IBCT)
Transfusion associated sepsis (TAS)
TACO
TRALI
Management:
- IV adrenaline/ hydrocortisone/ antihistamine
- IV fluid
- ventilation
- antibiotics
- FFP/platelets if DIC
Supportive measures aimed at reducing risk of sepsis in Haematological malignancy (pharmacological prophylaxis)
Antibiotics (ciprofloxacin)
Anti-fungal (fluconazole or itraconazole)
Anti-viral (aciclovir)
PJP (co-trimoxazole)
Supportive measures aimed at reducing risk of sepsis in Haematological malignancy (other than pharmacological prophylaxis)
Stem cell transplant
Protective environment (e.g. laminar flow rooms)
IV immunoglobulin replacement
Vaccination
Components of blood
Plasma
- clotting/coagulation factors
- albumin
- antibodies
Buffy coat
- platelets
- white cells
Red blood cells
Donated plasma is separated into 2 components…
+ associated lab tests
Fresh frozen plasma
lab tests = PT and APTT
Cryoprecipitate
lab tests = fibrinogen
Too many platelets
+ causes
thrombocytosis
- myeloid maligancies
- infection/inflammation (IBD, RA)
- post surgery/ trauma
- iron deficiency
Not enough platelets
+ causes
Thrombocytopenia
Decreased Production - marrow failure/infiltration Increased Consumption - ITP - non-immune DIC - hypersplenism
((These things cause ACQUIRED bleeding disorder))
too many neutrophils
+ causes
Neutrophilia
- Inflammation (MI, post-operative, rheumatoid arthritis)
- Infection
Not enough neutrophils
+ causes
Neutropenia
decreased production: - drugs (e.g. methotrexate) - marrow failure increased consumption: - sepsis - autoimmune
too many lymphocytes
+ causes
lymphocytosis
- Viral infection (e.g. EBV)
- Other infections (TB, brucellosis, syphilis)
- vasculitis
- lymphoid malignancies
not enough lymphocytes
+ causes
lymphopenia
- usually post-viral
- lymphoma
Normal range of haemoglobin
Male + female
Male: 135 - 170 g/L
Female: 120 - 160 g/L
Normal range of platelets
150 - 400 10^9 / L
has to be under 10 for spontaneous mucosal bleeding
Normal range of RBC
4-5 10^12 / L
Normal range of WBC
4-10 10^9/L
RED CELL donor/recipient compatibility
A can give to A
B can give to B
O can give to everyone
AB can receive from everyone
((antibodies are in plasma, antigens are on cells))
FFP donor/recipient compatibility
A can give to A
B can give to B
AB can give to everyone
O can receive from everyone
((reverse from red cells))
((antibodies are in plasma, antigens are on cells))
RhD negative individuals have a deletion of the RhD gene, they can receive red cells from…
ONLY other RhD -ve donors
RhD -ve idividuals can make anti-D if exposed to RhD+ cells
e.g. from transfusion or pregnancy
((anti-D can cause transfusion reactions/ haemolytic disease of the newborn
Steps of primary haemostasis after exposure to a breach in the endothelium (abnormal surface)
+ aim
Platelets…
- Adhere
- Activation (+degranulation)
- Aggregation
- Coagulation
Aim is to form a platelet plug
Primary haemostasis
Step 1: platelet adherence
Platelets adhere to collagen fibres in the subendothelium* via GP1a
GP1b binds to vWF
((GP = glycoprotein)) ((vWF = von Willebrand factor))
*exposed due to breach in endothelial surface
Primary haemostasis
Step 2: platelet activation (+degranulation)
Platelet changes shape + granules are released into the blood
- alpha: fibrinogen, vWF
- dense: serotonin, ADP, Ca2+
Production of thromboxane A2
Primary haemostasis
Step 3: platelet aggregation
caused by thromboxane A2
Primary haemostasis
Step 4: platelet coagulation
Scramblase flips the membrane, providing a phospholipid surface for coagulation
Secondary haemostasis =
+ formation of a stable clot
COAGULATION PATHWAY
a complicated cascade of coagulation factors (proteins)
+
Tissue factor (released when vessel damaged)
–>
conversion of prothrombin to thrombin
–>
conversion of fibrinogen to fibrin*
*Fibrin binds to the newly exposed phospholipid surface of the platelets in the platelet plug
==> a stable clot
Function of natural anticoagulants
confine a clot to the area of tissue damage
what natural anticoagulant inactivates thrombin and coagulation factor X
Antithrombin
what natural anticoagulant inactivates coagulation factors V and VIII
Protein C + Protein S
what natural anticoagulant inactivates coagulation factors Xa and VIIa
Tissue Factor Pathway Inhibitor (TFPI)
The process of getting rid of a clot is called…
fibronolysis
Fibrinolysis
endothelium produces tPA (a protease)
–>
“activates” plasminogen to form plasmin
–>
Plasmin fragments the fibrin clot producing
- fibrinogen
- fibrin degradation products (FDPs) - e.g. d-dimer
Drugs that inhibit platelet activation and aggregation
examples and mechanism of action
Clopidogrel, prasugrel, tricagrelor
Irreversibly bind to ADP receptors on platelets
Drugs that bind to GPIIb/IIIa, preventing binding of:
- fibrinogen
- von Willebrand factor
- other adhesive molecules
examples
Abciximab, tirofiban, eptifibatide
Mechanism of action of aspirin
inhibits cyclooxygenase (COX) enzyme - therefore inhibits thromboxane A2 formation
Mechanism of action of warfarin
inhibits several coagulation factors + prothrombin
Mechanism of action of heparins
inhibit thrombin and coagulation factor Xa
increases ability of antithrombin
Inhibitors of coagulation factor Xa
examples
Rivaroxaban, edoxaban, apixaban
Thrombin inhibitors
examples
dabigatran, bivalirudin, argatroban
Questions to ask in suspicious iron deficiency anaemia
Bleeding (inc. menorrhagia)
Pregnancy
Diet (esp. vegan)
GI symptomatology (may be malabsorption)
definitions of different sizes of bruising
Ecchymosis = >10mm Purpura = 3 - 10mm Petichiae = <3mm
((DON’T blanche - skin only blanches if blood is INSIDE blood vessels))
*FBC if any of these present
3 signs of bone marrow failure
↓ Hb (symptoms of anaemia)
↓ platelets (mucosal bleeding)
↓WCC (infections)
Be suspicious of haematological malignancy if lymphocyte count + neutrophil count =
less than total WCC
Lymphocytes found in normal peripheral blood
T cells
NOT B cells
Structure for breaking bad news
S - setting + listening skills (silence + pauses, “is there anybody here with you?”)
P - patient perception (“tell a bit about what’s been happening”)
I - invitation (“i’m afraid it’s bad news”)
K - knowledge (chunking + checking, “would you like me to continue”)
E - empathy (but don’t get upset, “we’ll be here with you through this”, “how are you feeling”)
S - summarise and strategy (give leaflets, explain next steps)
Substances related to bleeding and clotting produced by the liver:
Most clotting factors (I, II, V, VII, VIII, X, XI)
Fibrin
so liver failure = Increased risk of venous thrombosis AND bleeding
Red cell breakdown occurs in the…
reticuloendothelial system
consists of macrophages in the SPLEEN, liver, lymph nodes, lungs…
