Haematology Flashcards
What is ABO blood grouping?
inherityed surface antigens on RBCs
A- have A antigens on RBCs, and anti-B antibodies in plasma
B- Have B antigens on RBCs, and anti-A antibodies in plasma
AB- have both A and B antigens on RBCs, neither anti-A or anti-B antibodies
O- have neither A or B antigens on RBCs, have both anti- B and anti-A antibodies
What blood can type A receive
A, O
What blood can type B receive
B, O
What blood can type AB receive
A, B, AB, O
What blood can type O receive
O
Universal donor
What is Rhesus types
C, D and E antigens on RBCs
Rhesus -ve/+ve refers to the presence or absence of the D antigen
why are rhesus types important in pregnancy/childbirth
Rhesus negative (dd) mothers who are exposed to rhesus positive cells (from +ve baby), will make IgG anti-D antigens which ccan cross the placenta and haemolyse baby’s blood
What are the indications of fresh frozen plasma
- contains COAGULATION proteins, albumin, carrier proteins for nutrients/hormones, Ig
- lost about half of their blood volume- major haemorrhage protocol-
- actively bleeding with deranged clotting (PT, APTT, INR)
- consider prophylactically before surgery if clotting is deranged
- give units one by one and reassess coag status
When do you give platelets
- major haemorrhage
- thrombocytopenia (plt<30)
- prophylaxis pre-surgery if plt <50
do not routinely offer to pt with bone marrow failure, autoimmune thrombocytopenia, herpain induced thrombocytopenia, thrombotic thrombocytopenic purpura
- give one unit and reassess unless severely haemorrhaging
indications for cryoprecipitate
- significant bleeding and fibrinogen level <1.5g/L
- prophylactically for pts with fibinogen level <1g/L pre-surgery
- adult dose= 2 ‘pools’– reassess and repeat
what is in cyroprecipitate
fibrinogen, fibronectin, factor VIII, vWF, factor XIII
how do you order blood
- 2x group and saves from a pt taken 15 mins apart for safe blood typing
- likely need to code the reason for the request
- major haemorrhage– 2u of O- instant access
- prescribe either on fluid chart or on specific blood products chart- each unit needs to be it’s own px
how do you give blood products
- wide bore cannula to prevent haemolysis
- give over 2-3 hours in non urgent cases
- give within 30mins of leaving the fridge (should be warmed before administering)
- baseline obs at 0, 15, 30mins into the transfusion
Complications of blood transfusions
- acute haemolytic transfusion reaction- ABO incompatibility
- Anaphylaxis
- Transfuion related acute lung injury
- transfusion associated circulatory overload
- hypocalcaemia
- post transfusion purpura
- graft versus host disease
- transmission of blood borne diseases
what is acute haemolytic reaction (ABO incombatibility)
- Anti-a/b antibodies activate complement pathway, triggering inflammatory cytokine release
- most severe is when A is given to O pt
ix for ?acute haemolytic reaction
- blood film
- direct antiglobulin test
- retest both bloods (cross match and antibody screen)
tx acute haemolytic reaction
- stop transfusion
- fluid replacement
- FFP/platelets to tx DIC
- *- dopamine (vasodilation in the kidneys)
sx of acute haemolytic reaction
sx
- fever
- hypotension
- abdo/chest pain
- SOB
- haematuria and widespread haemorrhage (DIC)
what is transfusion related acute lung injury , sx
- not related to fluid overload (that is an immune response of unknown mechanism causing pulm oedema and ARDS)
- more typically due to FFP/plts than with red packed cells
sx- onset is sudden and severe, occurs within 6hours of transfusion:
- Dyspnoea
- Hypoxaemia
- hypotension
- fever
management of transfusion related acute lung injury
usually resolves within 48-96hours
- O2
- sometime ventilation
- fluids
- corticosteroids sometimes
What is transfusion associated circulatory overload
- hypervolaemia as a result of a transfusion
sx of transfusion assoc circulatory overload
- dyspnoea
- orthopnoea
- peripheral oedema
- rapid increase in BP
- pulmonary oedema
RF for tranfusion assoc circulatory overload
CVD kidney disease lung disease hypoalbuminaemia severe anaemia age (<3years old and >60)
Management of transfusion assoc circulatory overload
stop transfusion
oxygen
diretics (furosemide)
other tx for - ACEI/ARB, BB
why can hypocalcaemia occur after a transfusion, tx
- citrate (anticoagulant present in the bag) binds to free serum Ca in plasma, leaving the pt hypocalcaemic
- rare, only in massive transfusions
tx- calcium gluconate
What is post transfusion purpua, why does it occur
- immune reaction- antibodies to the new platelets’ antigens are produced, causing plt destruction leading to thrombocytopenia and bleeding under the skin
sx of post transfusion purpura
- purple rash
- 5-12 days after transfusion
tx post transfusion purpura
supportive
igG IV
what is graft versus host disease
White cells in donated tissue recognise the recipient as foreign
attack of host cells
what are some transmission of blood-borne disease
HIV Hep B, C syphillis malaria chagas disease (trypanosomiasis)- parasite
Name some P2Y12 receptor antagonist antiplatelets
clopidogrel
ticagrelor
prasugrel
name a COX inhibitor antiplatelet
aspirin
Name some GPIIIaIIB inhibitor antiplatelets
abciximab
tirofiban
eptifibatide
name some antithrombin anticoagulants
fondaparinux unfractionated heparin enoxaparin- LMWH dalteparin- LMWH tinzaparin- LMWH
name some factor Xa inhibitor anticoagulants
Rivaroxiban
apixaban
DOACs
name a vitamins K antagonist anticoagulant
warfarin
name some plasminogen activator anticoagulants
alteplase
reletplase
streptokinase is also a thrombolytic but is not used widely due to high levels of anaphylaxis
what is the difference between antiplatelets and anticoagulants
Anticoagulants
- inhibit clotting factors and fibrin
Antiplatelets
- inhibit enzymes that cause platelets aggregation
how do p2y12 inhibitors work
- ADP released from damaged endothelium and activated plts
- binds to P2Y12 receptor on platelet (which is blocked by these drugs)
- activates glycoproten IIB/IIa receptors, which causes fibrinogen mediated platelet cross-linking
how do cox inhibitors work
- when platelet is acitvated, arachidonic acid is released into the plt
- COX-1 metabs this into prostaglandin H2
- this is metab into thromboxane A2, which is released
- stimulates more platelets and aggregation
how do glycoprotein 2b.3a inhibitors work
- glycoproten IIB/IIa receptors, causes fibrinogen mediated platelet cross-linking
- administered only IV
contraindications for aspirin
- active peptic ulceration
- bleedgng disorders/haemophilia***
- <16y/o- Reye’s
- breastfeeding**
caution
- asthmatics
- HTN
what is reye’s syndrome
- rapid encephalopathy, hepatitis
sx
- vomiting
- change in personality
- confusion
- seizures
- LoC
SE of aspirin
- gastric irritation/bleeding
- asthmatic attack/bronchospasm
- reye syndrome in children
what is dual antiplatelet therapy
aspirin+ticagrelor - secondary prevention of MI
when is aspirin used
MI- 300mg tx/75mg prophylactic
secondary prevention of MI/DVT
- TIA (300mg, 75mg)
- acute ischaemic stroke 300mg
when are p2y12 inhibitors used
ticagrelor/clopidogrel
- prophylaxis during PCI
- alternative to aspirin in stroke
- dual antiplatelet therapt- secondary prevention post MI/vascular disease
What classes of drug are included in the umbrella term ‘antiplatelets’
COX inhibitors
P2Y12 inhibitors
Glycoprotein IIb/IIIa inhibitors
what class drugs are included in the umbrella term ‘anticoagulants’
NOACs/DOACs- factor Xa inhibs*****
Vit k antagonists - warfarin
Plasminogen activators- alteplase
Antithrombins- LMWH, unfract. hep.
mechanism of warfarin
vit K antagonism
blocks vit K oxide reductase
this usually activates vit K and uses vit k to produce factors 2 (prothrombin), 7, 9, 10
long half life- full effect not seen until a few days
may become hypercoagulable at first
indications for warfarin
- VTE tx
- TIA
- AF
- heart valve disease- rheumatic, mechanical, mitral
- inherited, symptomatic thrombophilia
warfarin interaction
enzyme inducers (decrease INR)- CRAPS (cabamazepine, rifampicin, bArbituates/alcohol chronic, phenytoin, St johns wort/sulphonylureas)
vit K (leafy greens)
enzyme inhibitors (increase INR) Some, certain Damn Silly Compounds Annoyingly Inhibit Enzymes GRR Sodium Val, Cipro, Dilitiazem, Sulphonamide, Cimetidine/omezop, antifungals/Amiodarone, Isoniazid, Erythro/clarithro, Grapefruit juice
AODEVICES- Allopurinol, omezoprazole, disulfiram, erythro, valproate, isoniazid, cipro, ehtanol (acute), sulphonamides
monitoring of warfarin
amount adjusted to maintain:
2-3 INR (venous embolism, AD, Mitral valve, inherited thrombophilia)
2.5-3.5- mechanical heart valves
how are the effects of warfarin reversed eg for emergency surgery
- witholding warfarin
- vit K (oral/IV)– phytomenadione
- prothrombin complex concentrate- have factors 2,7,9,10
pt info for warfarin
- take before, during or after a meal OD
- remember to take dose
- do NOT double dose
- no piercings or tattoos
- must always stick with same brand (bioavailabilities differ)
- seek urgent medical help if theres’ blood in stool/urine/black poo/severe bruising/long nosebleeds/significant blow to the head/any signs of bleeding or prologned bleeding
- always check new meds/OTC meds can be taken with warfarin
What does bridging anticoagulant medication mean
- pts taking vit k antagonists at high risk of thromb emb (VTE in last 3m, AF with previous stroke/TIA, mitral mechanical valve)
- warfarin stopped in perioperative period, so require unfractinated heparin or LMWH in interim
- using tx dose
- LMWH then stopped 24hours before surgery
How are the effects of LMWH and unfractionated herparin reversed
protamine
LMWH- partially (60%)
UFH- fully
what is polycythaemia
too many RBCs
causes of polycythaemia
- Primary- Polycythaemia rubra vera (overactive bone marrow)
Secondary
- lung disease, smoking
- living at high altitude
- pregnancy**
- malignancy
- kidney disease/RCC– too much EPO**
- CYANOTIC heart disease
sx of polycythemia
- plethoric face
- thrombosis/VTE
- pruritis
- splenomegaly /abdo discomfort
- unusual bleeding (nosebleeds)
- severe headache, dizziness
- fatigue
- paraesthesia
ix for ?polycythemia rubra vera
- FBC
- JAK2 on genotyping
- USS abdo- kidneys, spleen
management of polycythemia rubra vera
- venesection
management of secondary polycythemia
aspirin- reduced risk of clots
- venesection
- bone marrow supression - hydroxycarbamide, interferon
Causes of anaemia
MCV <80
- iron deficiency
- thalassaemia
- haemoglobinopathies
- ** sideroblastic anaemia (iron cannot be incorp into RBC)***
- chronic disease (incl. kidney, less common)
- lead
MCV 81-95
- blood loss
- chronic disease (incl. kidney, more common)
- pregnancy
- haemolysis ***
- combined iron/b12/folate deficiency
MCV >96– ABCDEF
- alcoholic/ liver disease**
- b12 deficiency
- compensatory reticucytosis
- drugs- cytotoxic
- endocrine- hypothyroid
- Folate deficiency/foetus
presentation of anaemia
fatigue, faintness, anorexia
dyspnoea
palpitations, angina
headache, tinnitus
Signs:
- pallor- conjunctival
- tachycardia
- jaundice if haemolytic
ix for anaemia
- Bloods- FBC (hb, MCV), iron studies, haematinics (B12/folate)
- *- blood film- reticulocyte count
- FIT, LFTs
- *- USS spleen, kidney
- *- direct coombs
- genetic testing
management of anaemia
Acute anaemia/v symptomatic
- ferinject (IV iron)
- transfusion if Hb <70 ro <80+IHD
Chronic
- iron/folate/b12 supplements and diet advice
how do you interpret reticulocyte count
high (megaloblastic)- producing lots of, large, immature RBCs:
- bone marrow working well to compensate for anaemia
- loss of blood (chronic)
- hypersplenism
- haemolysis
Low (non-megalobastic)
- bone marrow is working not well
- do MCV
- Mircocytic- iron, thalassaemia, sideroblastic
- normocytic- kidneys, chronic, acute bleeds
- macro- b12/folate, hypothyroid, bone marrow failure
causes of hypersplenic megaloblastic anaemia (and Ixs)
- congestion (LFTs, portal vein doppler, abdo imaging, d-dimer)
- infiltration (protein electrphoresis, blood film (malignancies), spleen biopsy
- poliferation- viral serologies, blood film (RBC abnomrlaities)
causes of megalobastic, haemolytic anaemia (and ixs)
A type of macrocytic anaemia– Bone marrow producing large, immature RBC , due to increased rates of haemolysis
bilirubin and LFTs deranged
Extrinsic
Immune- direct coombs:
-drug induced (penicillin, quinine)
-autoimmune- SLE, infection, idiopathic
-Infection- malaria- blood film
DIC- coag profile
Thrombotic thrombocytopenic purpura- low plts due to clots
Intrinsic- genetic and blood film testing: Enzyme defects - G6PD (xlinked, broad beans) - Pyruvate Kinase, Membrane defects: -spherocytosis -ellipotcytosis -ovalocytosis -stomatocytosis Haemoglobinopathoes -sickle cell -thalassaemia
specific sx of iron deficiency anaemia
- koilonychia (soft, scooped out/spoon nails)
- angular cheilitis
- atrophic glossitis- swollen, painful/itchy tongue
ix results in iron deficiency anaemia
- Hb low
- MCV <80
- reticulocyte count low
tx for iron deficiency anaemia
- ferrous sulphate 200mg TDS PO for at least 3 months
- urgent 2ww if >60 or women >55 with PMB
- consider coeliac screen, urine dipstick, stool sample for parasites, FIT
SE of ferrous sulfate
black stools
diarrhoea, constipation
nausea
normal hb levels
120-180 g/L
Specific sx for b12/folate deficiency
v. insidious
- pallor, jaundice, glossitis
- mood- irritability, depression, psychosis
NEURO:
- sensory neuropathy- paraesthesia
- upper and lower motor neuron signs (extensor plantar, absent reflexes, ataxia)
- weakness
- urinary incontinence
- optic neuropathy
management of b12/folate deficiency
always correct b12 Before starting folate as folate can hide sx of b12 deficiency and if untx–> spinal cord degeneration
hydroxocobalamin IM then folic acid
what is pernicious anaemia
- b12 deficiency due to autoimmune atrophic gastritis
- parietal cells in stomach destroyed
- reduced intrinsic factor secretion
- reduced b12 absorption in terminal ileum
management of pernicious anaemia
- 1mg IM hydroxocobalamin for life
3x a week for 2w, then every 2-3m
what is sideroblastic anaemia
- ineffective erythropoeisis
- leading to increased Iron absorption and iron loading in marrow (not in RBCs)
- production of erythrocytes with ferritin granules in them that cannot incorporate the iron in the Hb (sideroblasts)
- these get deposited into endocrine organs, liver and heart
causes of sideroblastic anaemia
- congenital
- malignancy- CML
- alcohol
Iatrogenic:
- chemo
- anti-TB drugs
- irradiation
sx of sideroblastic anaemia
pallor
fatigue
dizziness
hepatosplenomegaly
tx of sideroblastic anaemia
tx cause
blood transfusion and iron chelation
**pyridoxine (vit B6)***
sx of haemolytic, megaloblastic anaemias
- anaemia sx
- jaundice
- dark urine
ix for ?haemolyic anaemia
- malaria testing
- Coomb’s test (autoimmune causes)
- FBC, LFTS
- blood film- malaria, RBC deformities
- LDH levels- raised
- Hb electrphoresis- sickle cell, thalassaemia
- sickle solubility test
precipitants of glucose 6 phosphate deficiency
Broad beans
Primaquine
Sulphonamides
- Dapsone (gangrene, hermatitis, herptiformis, bascuitits)
Nitrofurantoin
Quinolones- cipro
infection
stress
inheritance pattern G6PD
x linked
recessive
inheritance pattern membranopathies
dominant
inheritance pattern sickle cell
recessive
what is sickle cell anaemia
- Hb conatins an abnormal Hb globin chain
- single base substitution in beta chain
- creates HbS which changes the solubility of Hb and damages the cell containing it
- inflexible
sx sickle cell disease
Homozygous- severe sx
Heterozygous- may have mild sx
- from 3- 6 months of age as HbF replaced by HbSS (instead of Beta)
- anaemia sx
- growth restriction, delayed puberty
- recurrent infections
Sickle crises
- acute painful crisis due to vaso-occ
- sequestrian crisis
- hyperhaemolytic crisis
- acute chest syndrome- chest pain, SOB
- splenomegaly, asplenism
ix for sickle cell
FBC- anaemia LFTS- bilirubin Blood film sickle solubility test Hb electrophoresis- diagnostic
neonatal screening- heel prick
How to avoid sickle cell crises
- avoid triggers- cold temps, dehydration, exhaustion, alcohol, smoking
- prevent infections- oral penicillin, vaccination
- folic acid supplementation
tx of sickle cell
- blood tranfusions
- iron chelation
- hydroxycarbamide (B12) OD (increase HbF)
- stem cell/bone marrow transplant
management of sickle crisis
- paracetemol, ibuprofen
- opioids
- IV fluids
- O2 to avoid acute chest
- empirical broad spec abx if fever
what is a sequestration crisis, tx
erythrocytes trapped in spleen– causing dangerous drop in circulating blood vol, infarction, atrophy
Acute anaemia:
- profound pallor, SOB, weakness
- Acute splenomegaly
- Shock
urgent transfusion
what is an aplastic crisis, sx, tx
- temporary cessation of erythropoesis
- usually due to parvovirus b19
sx
- severe anaemia- SOB, pallor, weakness
- may present as high output congestive HF- SOB, oedema
- tx- blood transfusion
What is thalassamia
reduced synthesis of alpha or beta chains with consequent reduction of haemoglobin
presentation of beta thalassaemia
MAJOR
- present at 6-12 months of age (beta chains replace gamma)
- Failure to feed
- listless, crying
- pale
- anaemia
types of beta thalassaemia
major- no beta chain at all, transfusion dependent
intermedia- microcytic anaemia, can survive without transfusions
Carrier/heterozygote- clinically well
pathophysiology of beta thalassaemia
beta chain production affected
only become apparent when adult Hb replaces HbF (Y chains–> b chains)
ix ?thalassaemia
FBC- severe anaemia, low MCV- MICROCYTIC, reticuloyes low (non-megaloblastic)
blood film- large and small, irregular pale red cells
HbF >90% in foetal sample
A thalassaemia- pathophysiology
- production of alpha chain affected, meaning HbF is affected
- 4 alleles involved- 2 mum, 2 dad
- generally caused by deletion mutations
presentation of alpha thalassaemia
depends on how many alleles are involved
1- asymptomatic
2- asymptomatic but low MCV
3- moderate anaemia and features of haemolysis eg hepatosplenomegaly, leg ulcers
4- Bart’s hydrops (foetal death)
What is thrombocytosis
too many platelets (>450)
causes of thrombocytosis
Primary (thrombocytopemia)- NOT thrombocytoPENIA
- essential thrombocytopemia
- Polycythemia rubra vera- increased RBC with also hgih WCC and plt in most cases
- haematological malignancy (CML)
- primary myelofibrosis - scarring of BM, can cause high or low plts
Secondary
- chronic inflammation
- severe systemic infection
- bleeding/healing, clotting- surgery/trauma
- malignancy