Haematology Flashcards
(248 cards)
1
Q
Blood made up of?
A
plasma (the liquid of the blood) that contains red blood cells, white blood cells and platelets. The plasma also contains lots of clotting factors such as fibrinogen (forms blood clots)
Once the clotting factors are removed from the blood what is left is called the serum.
Serum contains:
o Glucose
o Electrolytes such as sodium and potassium
o Proteins such as immunoglobulins and hormones
2
Q
Bone marrow is found?
A
pelvis, vertebrae, ribs and sternum
3
Q
Blasts
A
nucleated precursor cell
- erthyro
- myelo
4
Q
Reticulocytes
A
immediate red cell precursor, ‘polychromasia’
5
Q
Myelocytes
A
nucleated precursor between neutrophils and mylo-blasts
6
Q
Haemopoiesis Myelopoiesis or Granulopoiesis Lymphopoiesis Erythropoiesis Thrombopoiesis
A
The formation of blood cells o (Neutrophils, eosinophils, basophils, monocytes/macrophages) B and T cells RBC platelets
7
Q
Embryo of blood cells
A
Orignate in mesoderm
Yolk sac (stops at week 10) then liver (week 6) then marrow (week 16)
3rd to 7th month – spleen
8
Q
Myeloid: erythroid ratio
A
relationship of neutrophils and precursors to proportion of nucleated red cell precursors
9
Q
What regulates haemopoiesis?
A
- Intrinsic properties of cells (e.g stem cells vs progenitor cells vs mature cells)
- Signals from immediate surroundings and the periphery (microenvironmental factors)
- Specific anatomical area (‘niche’) for optimal developmental signals
10
Q
How do we assess haemopoiesis?
A
Morphology of cells
immunophenotyping
• Identify patterns of protein (antigen) expression unique to a cell lineage
• Use antibodies (in combination) specific to different antigens
11
Q
Pluripotent Haematopoietic Stem Cell
A
undifferentiated cells that have the potential to transform into a variety of blood cells.
They initially become:
o Myeloid Stem Cells
o Lymphoid Stem Cells
o Dendritic Cells (via various intermediate stages)
12
Q
Properties of Pluripotent Haematopoietic Stem Cell
A
- Self-renewal: a property of stem cells, lost in descendants
- Proliferation: increase in numbers
- Differentiation: descendants commit to one or more lineages
- Maturation: descendants acquire functional properties and may stop proliferating
- Apoptosis: descendants undergo cell death
13
Q
RBC surivive for how long?
A
3 months
14
Q
RBC order
A
Pronormoblast early normoblast intermediate normoblast late normoblast reticulocyte erythrocyte
15
Q
Platelets precursor and lifespan
A
megakaryocytes and 10 days
16
Q
Neutrophil maturation
A
myeloblast to promyelocyte to myelocyte through metamyelocyte forms eventually to band forms and neutrophils
17
Q
Neutrophil structure and function
A
- Segmented nucleus (polymorphs): nucleus condenses into many lobes?
- Neutral staining granules
o Short life in circulation almost 1 day
o Phagocytose invaders
o Kill with granule contents and die in the process (causes pus to go green)
o Attract other cells and complement
o Increased by body stress – infection, trauma (fractured bone) and infarction (MI)
18
Q
Eosinophils structure and function
A
o Usually bi-lobed
o Bright orange/red granules
o Fight parasitic infection
o Involved in hypersensitivity (allergic reactions)
o Often elevated in patients with allergic conditions (e.g. asthma, atopic rhinitis
19
Q
Basophils structure and function
A
o Quite infrequent in circulation
o Large deep purple granules obscuring nucleus
o Circulating version of tissue mast cell o Role? o Mediates hypersensitivity reactions o Fc Receptors bind IgE o Granules contain histamine
20
Q
Monocytes
A
o Large single nucleus (can be kidney shaped)
o Faintly staining granules often vacuolated
o Got open chromatin structure than other cells
o Circulate for a week and enter tissues to become macrophages
o Phagocytose invaders
Kill them
antigen to lymphocytes: MHC II – T helper cells
o Attract other cells
o Much longer lived than neutrophils
21
Q
Central (Primary) lymphoid tissues
A
o Bone marrow
o Thymus
22
Q
Peripheral (Secondary) lymphoid tissues
A
o Lymph nodes
o Spleen
o Tonsils (Waldeyer’s ring)
o Epithelio-lymphoid tissues
23
Q
Lymphocytes structure and function
A
o Mature – small with condensed nucleus and rim of cytoplasm o Activated (often called atyical) – large with plentiful blue cytoplasm extended round neighbouring red cells in the film, nucleus more open structure
24
Q
Target cells
A
central pigmented area, surrounded by a pale area, surrounded by a ring of thicker cytoplasm on the outside.
o This makes it look like a bull’s eye target.
o These can be seen in iron deficiency anaemia and post-splenectomy.
25
Heinz Bodies
individual blobs seen inside red blood cells caused by denatured globin.
They can be seen in G6PD and alpha-thalassaemia.
26
Howell-Jolly bodies
individual blobs of DNA material seen inside red blood cells.
o Normally this DNA material is removed by the spleen during circulation of red blood cells.
o They can be seen in post-splenectomy and in patients with severe anaemia where the body is regenerating red blood cells quickly.
27
Schistocytes
fragments of RBC
haemolytic uraemic syndrome, disseminated intravascular coagulation (DIC) or thrombotic thrombocytopenia purpura.
They can also be present in replacement metallic heart valves and haemolytic anaemia.
28
Sideroblasts
immature red blood cells that contain blobs of iron.
They occur when the bone marrow is unable to incorporate iron into the haemoglobin molecules. They can indicate a myelodysplasic syndrome
29
Smudge cells
ruptured white blood cells that occur during the process of preparing the blood film due to aged or fragile white blood cells.
o They can indicate chronic lymphocytic leukaemia.
30
Spherocytes
spherical red blood cells without the normal bi-concave disk space.
They can indicated autoimmune haemolytic anaemia or hereditary spherocytosis.
31
Consequences of red blood cell structure
Full of haemoglobin: High oncotic pressure (draws water in), oxygen rich environment (oxidation risk)
o Na/K+ ion pump: Keeps water out – as there is a drive for water to go into due to high oncotic pressure. Don’t want it to inflate
* No nucleus: Can’t divide, can’t replace damaged proteins - limited cell lifespan
* No mitochondria: Limited to glycolysis for energy generation (no Krebs’ cycle)
* High Surface area/volume ratio: Need to keep water out
* Flexible: Specialised membrane required that can go wrong
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Haemoglobin structure
* A tetrameric globular protein (4 subunits)
* HbA (Adult) is 2 alpha and 2 beta chains
* Heme group is Fe2+ in a flat porphyrin ring
* One heme per subgroup
* One oxygen molecule binds to one Fe2+ (Oxygen does NOT bind to Fe3+)
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RBC recycling
* Globin chains recycled to amino acids
* Heme group broken down to iron and bilirubin (porphyrin, biliverdin, bilirubin)
* Bilirubin taken to liver and conjugated
* Then excreted in bile (colours, faeces and urine)
34
Protects us from free radicals?
* Glutathione protects us from hydrogen peroxide by reacting with it to form water and an oxidised glutathione product (GSSG).
* This can be replenished by NADPH which in turn is generated by the hexose monophosphate shunt
* The rate limiting enzyme in this process is glucose-6-phosphate dehydrogenase (G6PD)
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Hb affect
Allosteric affect
one oxygen binds to a subunit the Hb shape changes. This alters how easy it is for the next O2 to bind to a different subunit
36
Rapapoport lubering shunt
* Curve is shifted right by molecules that interact with Hb (H+, CO2, 2,3 BPG).
* This results in more O2 delivered to tissues.
* 2,3 BPG (or sometimes called DPG) is increased in chronic anaemia
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ABO system - dominance
A and B are dominant over O
A and B are co-dominant
O is silent: lack of A or B
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RhD
* 2 alleles D and d, inherit one from each parent
* d is silent
* Very immunogenic
* Anti-D antibody can cause transfusion reactions and haemolytic disease of the fetus and newborn
* Avoid exposing RhD negative people to D antigen through transfusions
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Pre transfusion testing: ABO grouping
1) Use reagents with known antibody specificity to identity antigens present on red cells (Antisera)
2) Use red cells with known antigen specificity to identify antibodies present in plasma
o Reagent red cells
o Group B reagents cells – anti B in patient plasma
Antisera: looking for the postive result
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ABO/D grouping: steps
1. ) Tests patients red cells with anti-A, anti-B and anti-D antisera
a. Identify antigens on the red cells
b. IgM reagents – direct agglutination
2. ) Test patients plasma against reagent red cells of group A and group B
a. Identify antibodies in the plasma
3.) Define the patient blood group
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Antibody screening
• Test patient plasma against several reagent red cells which express a known range of antigens
• Identify antibodies in the plasma
• Use the indirect anti-globulin test
o Addition of anti-human globulin (AHG) to plasma/red cell suspension facilities red cell agglutination
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Indication for red cell transfusion
Symptomatic anaemia Hb < 70 g/L (80g/L if cardiac disease)
Major bleeding
Always consider cause before transfusion – is there an alternative
Transfuse a single unit of red cells and then reassess patient
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Indications for platelets
* Prophylaxis in patients with bone marrow failure and very low platelet counts
* Treatment of bleeding in thrombocytopenic patient
* Prophylaxis prior to surgery/procedure in thrombocytopenic patien
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Indications for FFP transfusion
* Treatment of bleeding in patient with coagulopathy (PT ratio >1.5)
* Prophylaxis prior to surgery or procedure in patient coagulopathy (PT ratio >1.5)
* Management of massive haemorrhage
* Transfuse early in trauma (1FFP to one 1 unit)
45
Acute transfusion reactions (ATR)
usually within 24 hours
Intravascular haemolysis of transfused cells
46
ATR signs/symptoms
* Chills, rigor, rash, flushing, feeling of impending doom, collapse, loin pain and resp distress
* Fever, tachycardia, hypotension,
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ATR Mx
* Stop transfusion
* Assess patient urgently ABCDE (bp, pulse, temp, o2 sats, clinical examination)
* Recheck compatibility tag against patient details and inspect for evidence of contamination
* Document event in medical notes
* Repeat transfusion blood samples
* Bloods for FBC, coagulation screen, renal function and measures of haemoltis, blood cultures
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Transfusion associated circulatory overload (TACO) signs/symptoms
o Respiratory distress within 6 hours of transfusion
o Raised BP
o Raised JVP
o Positive fluid balance
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TACO risk factors
Elderly patients, cardiac failure, low albumin, renal impairment and fluid overload
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TACO Mx
* Oxygen and supportive care as required
* Diuretics
* Consider slowing rate of further transfusions
* Consider diuretics with future transfusion
* Only transfuse minimum volume required
* Aim to identify patients at risk before first transfusion
51
Mild reactions from blood transfusion
Isolated temp rise > 38 and rise of 1-2 degrees or rash only
52
Causes of mild reactions of blood transfusion
Febrile non-haemolytic transfusion reaction
o Less common since universal leucodepletion
o Consider premedication with paracetamol if patient suffers repeated reactions
Mild allergic reaction
o Rash/itch but normal observations
o Commoner with plasma rich components
o Treat with anti-histamines
53
Delayed haemolytic transfusion reactions
Patient mounts delayed immune response to red cell antigen – usually IgG
o positive DAT
extravascular haemolysis 5-10 days post transfusion
transfused cells destroyed
o Hb may drop, raised bili, LDH
o Positive DAT and detection of alloantibody
54
Anaemia
Reduced total red cell mass, we use Haemoglobin concentration is a surrogate marker
Anaemia is defined as a low level of haemoglobin in the blood.
result of underlying disease and not disease itself
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Anaemia ranges
120-165: women
130-180: men
MCV: 80-100 (both)
56
Microcytic Anaemia
Deficient haemoglobin synthesis: cytoplasmic defect
• Hb is synthesised in the cytoplasm
• To make Hb need all the building blocks. One of these is lacking in microcytic anaemias
o Globins: too put haem groups in to
o Haem: Porphyrin ring & Iron (Fe 2+)
* The nuclear machinery is intact however- so cells can keep dividing
* As a result the cells are microcytic (small)
* And as the contain little Hb they are hypochromic (lacking in colour)
Under 80: problem with haemoglobinisation
57
Microcytic anaemia causes
o T – Thalassaemia
o A – Anaemia of chronic disease: normal body iron
o I – Iron deficiency anaemia: most common
o L – Lead poisoning
o S – Sideroblastic anaemia: excess iron build up in mitochondria (blue granules around nucleus) due to failure to incorporate iron in to haem.
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Normocytic Anaemia Causes
```
o A – Acute blood loss
o A – Anaemia of Chronic Disease
o A – Aplastic Anaemia
o H – Haemolytic Anaemia
o H – Hypothyroidism
```
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Macrocytic Anaemia causes
If MCV high (macrocytic) consider problems with maturation
• Macrocytic anaemia can be megaloblastic or normoblastic.
• Megaloblastic anaemia is the result of impaired DNA synthesis preventing the cell from dividing normally. Rather than dividing it keeps growing into a larger, abnormal cell. This is caused by a vitamin deficiency.
• Megaloblastic anaemia is caused by:
o B12 deficiency
o Folate deficiency
Normoblastic macrocytic anaemia is caused by:
o Alcohol
o Reticulocytosis (usually from haemolytic anaemia or blood loss)
o Hypothyroidism
o Liver disease
o Drugs such as azathioprine
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signs/Symptoms of anaemia
• Tiredness
• Shortness of breath
• Headaches
• Dizziness
• Palpitations
• Worsening of other conditions such as angina, heart failure or peripheral vascular disease
o Pica describes dietary cravings for abnormal things such as dirt and can signify iron deficiency
o Hair loss (gradual patchy hair loss) can indicate iron deficiency anaemia
Signs of Anaemia
• Pale skin
• Conjunctival pallor
• Tachycardia
• Raised respiratory rate
• Signs of specific causes of anaemia:
o Koilonychia is spoon shaped nails
o Angular chelitis can indicate iron deficiency
o Atrophic glossitis is a smooth tongue due to atrophy of the papillae
o Brittle hair and nails can indicate iron deficiency
o Jaundice occurs in haemolytic anaemia
o Bone deformities occur in thalassaemia
o Oedema, hypertension and excoriations on the skin can indicate chronic kidney disease
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Investigating Anaemia
```
Hb - not as useful in rapid blood loss or haemodilution
MCV
B12
Folate
ferritin
Blood film
```
Oesophago-gastroduodenoscopy (OGD) and colonoscopy to investigate for a gastrointestinal cause of unexplained iron deficiency anaemia. This is done on an urgent cancer referral for suspected gastrointestinal cancer.
Bone marrow biopsy may be required if the cause is unclear
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Reticulocytosis and reticulocytes
Increase red cell production
* Reticulocytes: Red cells that have just left the bone marrow
* Larger than average red cells
* Still have remnants of protein making machinery (RNA)
* Stain purple/deeper red as a consequence due to remnants of protein making machinery (RNA)
* Blood film appears 'polychromatic'
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Classification of anaemia's (decreased production and increased loss)
Decreased production: under functioning bone marrow and decreased retic count
o Hypoproliferative – reduced amount of erythropoiesis
o Maturation abnormality – erythropoiesis present but ineffective:
Cytoplasmic defects (low MCV): impaired haemoglobinisation
Nuclear defects (High MCV): impaired cell division
Increased loss or destruction of red cells
o Bleeding
o Haemolysis
• Use retic count as a surrogate marker to distinguish between these
• If there is a reticulocytosis (increase) then look for red cell breakdown products
• If bleeding - red cells are gone, nothing to breakdown
• If haemolysing then increased products of red cell destruction are seen
o Increased unconjugated serum bilirubin
o Increased urinary urobilinogen
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Iron Deficiency Anaemia
bone marrow requires iron to produce haemoglobin
o Insufficient dietary iron
o Iron requirements increase (for example in pregnancy)
o Iron is being lost (for example slow bleeding from a colon cancer)
o Inadequate iron absorption
Iron absrobed in duodenum and jejunum . Needs acid from stomach to keep in Fe2+ form (soluble).
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Conditions and medications that interefere with Fe2+ (make insoluble Fe3+)
* Therefore, medications that reduce the stomach acid such as proton pump inhibitors (lansoprazole and omeprazole) can interfere with iron absorption.
* Conditions that result in inflammation of the duodenum or jejunum such as coeliac disease or Crohn’s disease can also cause inadequate iron absorption.
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Mechanisms of Iron Absorption
• Duodenal cytochrome B
o Found in luminal surface
o Reduces ferric iron (Fe3+) to ferrous form (Fe2+)
• DMT (divalent metal transporter) -1
o Transports ferrous iron into the duodenal enterocyte
• Ferroportin
o Facilitates iron export from the enterocyte
o Passed on to transferrin for transport elsewhere
• Hepcidin: The major negative regulator of iron uptake
o Produced in liver in response to increased iron load and inflammation
o Binds to ferroportin and causes its degradation
o Iron therefore ‘trapped’ in duodenal cells and macrophages
o Hepcidin levels decrease when iron deficient
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Iron deficiency causes
Chronic Blood loss is the most common cause in adults e.g. heavy menstrual loss (most common in women), colon cancer (women not menstruating and men: dont forget gastritis or oesophagitis and IBD), Haematuria, ulcers, NSAIDs and parasitic infection
Achlorhydria: lack of stomach acid
Dietary Insufficiency is the most common cause in growing children
Poor iron absorption
Increased requirements during pregnancy
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Iron transport
Iron travels around the blood as ferric ions (Fe3+) bound to a carrier protein called transferrin: donor tissues to transferrin receptors (marrow)
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Total iron binding capacity (TIBC)
total space on the transferrin molecules for the iron to bind. Therefore, total iron binding capacity is directly related to the amount of transferrin in the blood.
Both TIBC and transferrin levels increase in iron deficiency and decrease in iron overload
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Transferrin Saturation
If you measure iron in the blood and then measure the total iron binding capacity of that blood, you can calculate the proportion of the transferrin molecules that are bound to iron
Transferrin Saturation = Serum Iron / Total Iron Binding Capacity
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Ferritin
form that iron takes when it is deposited and stored in cells
If low: highly suggestive of iron deficiency
if high: inflammation or iron overload
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Iron deficiency Dx
confirmed by a combination of anaemia (decreased functional iron) and reduced storage iron (low serum ferritin)
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Iron deficiency Ix and Mx
New iron deficiency in an adult without a clear underlying cause (for example heavy menstruation or pregnancy) should be investigated with suspicion
• oesophago-gastroduodenoscopy (OGD) and a colonoscopy to look for cancer of the gastrointestinal tract.
Mx (fastest to slowest)
o Blood transfusion. This will immediately correct the anaemia but not the underlying iron deficiency and also carries risks.
o Iron infusion e.g. “cosmofer”. There is a very small risk of anaphylaxis but it quickly corrects the iron deficiency. It should be avoided during sepsis as iron “feeds” bacteria.
o Oral iron e.g. ferrous sulfate 200mg three times daily. This slowly corrects the iron deficiency.
Oral iron causes constipation and black coloured stools.
It is unsuitable where malabsorption is the cause of the anaemia
- expect 10 grams/litre per week rise
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Iron Malutilisation: ‘Anaemia of chronic disease’
Multifactorial with inflammation at the core of it
• Multiple mechanisms all driven by inflammatory cytokines induced by infection/malignancy/autoimmune disease dysregulation
o Blunted EPO response by kidney - cytokines interfering
o Impaired iron availability to erythroid precursors: Hepcidin
o Inhibition of proliferation
o Reduced red cell survival
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Differentiating iron deficiency vs anaemia of chronic disease
Ferritin
iron deficiency: reduced
anaemia of chronic disease: normal or increased
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Megaloblastic anaemia causes
o B12 deficiency
o Folate deficiency
o Drugs
o Rare inherited abnormalities of metabolism
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Normoblastic macrocytic anaemia causes
```
o Alcohol
o Reticulocytosis (usually from haemolytic anaemia or blood loss)
o Hypothyroidism
o Liver disease
o Drugs such as azathioprine
o Marrow failure: associated with anaemia
Myelodysplasia
Myeloma
Aplastic anaemia
```
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Megoblastic pathophysiology
Megaloblast: abnormally large nucleated red cell precursor with an immature nucleus
* Megaloblastic anaemias are characterised by lack of red cells due to predominant defects in DNA synthesis and nuclear maturation in developing precursors cells (megaloblasts) in the marrow
* In maturing megaloblasts, division is reduced and apoptosis increases
* Cytoplasmic development and haemoglobin synthesis accumulation occur normally and so the precursor cell is bigger with an immature nucleus
* Once Hb level in the cell is optimal , the nucleus is extruded, leaving behind a bigger than normal red cell i.e. macrocyte
* But overall there are fever macrocytes and hence anaemia
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B12 and folate are essential co factors in linked biochemical reactions regulating
* DNA synthesis and nucleus maturation e.g. blood cell effect
* DNA modification and gene activity e.g. nervous system – myelin in NS
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Folate absorbed? Causes ?
Absorbed in jejunum (diffusion and actively)
* Inadequate intake: dietary cause more likely than B12 due to lesser stores e.g. alcoholics
* Malabsorption: coeliac and crohn's disease
* Excess utilisation: haemolysis, exfoliating dermatitis, pregnancy and malignancy
* Drugs: anticonvulsants
81
Clinical features of B12/folate deficiency
Common to both B12 and folate
o Symptoms and signs of anaemia e.g. breathlessness and fatigue
o Weight loss, diarrhoea and infertility
o Sore tongue and jaundice: haemolysis in the bone marrow – excess bilirubin
o Developmental problems
More with vitamin B12 deficiency (?myelin)
o Neurological problems – posterior/dorsal column abnormalities, neuropathy, dementia, psychiatric manifestations
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Folate/B12 Ix
MCV high and anaemia
• Pancytopenia (all cells low) in some patients
• Blood film shows macrovaloyctes and hypersegmnted neutrophils (normally 3-5 nucleur segments)
• Assay B12 and folate levels in serum
• Check for autoantibodies
o Anti-gastric parietal cell (GPC) – flaw: sensitive not specific
o Anti-intrinsic factor (IF) – flaw: specific, not sensitive
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B12/folate Mx
* Vitamin B12 (Hydroxocobalamin in Europe) injections for life in pernicious anaemia (high dose oral B12 though to be effective)
* Folic acid tablets (5mg per day) orally: different from routine pregnancy recommendation
* Only if potentially life-threatening anaemia, transfuse red cells
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Spurious macrocytosis causes
reticulocytosis
Agglutinins
85
Pernicious Anaemia
Pernicious anaemia is an autoimmune condition where antibodies form against the parietal cells or intrinsic factor.
• A lack of intrinsic factor prevents the absorption of vitamin B12 and the patient becomes vitamin B12 deficient.
• Vitamin B12 deficiency can cause neurological symptoms:
o Peripheral neuropathy with numbness or paraesthesia (pins and needles)
o Loss of vibration sense or proprioception
o Visual changes
mood or congitive changes
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Pernicious Anaemia Mx
• In pernicious anaemia oral replacement is inadequate because the problem is with absorption rather than intake.
o They can be treated with 1mg of intramuscular hydroxocobalamin 3 times weekly for 2 weeks, then every 3 months
• If there is also folate deficiency it is important to treat the B12 deficiency first before correcting the folate deficiency.
• Treating patients with folic acid when they have a B12 deficiency can lead to subacute combined degeneration of the cord.
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Consequences of Haemolysis
* Erythroid hyperplasia (increased bone marrow red cell production)
* Excess red cell breakdown products e.g. bilirubin (clinical features differ by aetiology and site of red cell breakdown)
* Bone marrow response: Reticulocytosis and erythroid hyperplasia
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Blackwater fever parasite
Falciparum malaria
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Autoimmune Haemolytic Anaemia (AIHA)
* Premature destruction of normal red cells (immune)
* Autoimmune haemolytic anaemia occurs when antibodies are created against the patient’s red blood cells.
* These antibodies lead to destruction of the red blood cells
90
AIHA types
Warm type autoimmune haemolytic anaemia
• Haemolysis occurs at normal or above normal temperatures.
• It is usually idiopathic, secondary to:
o Autoimmune disorders (SLE)
o Lymphoproliferative disorders (CLL)
o Drugs (penicillins, etc)
o Infections
Cold: At lower temperatures (e.g. less than 10ºC) the antibodies against red blood cells attach themselves to the red blood cells and cause them to clump together.
• This agglutination results in the destruction of the red blood cells as the immune system is activated against them and they get filtered and destroyed in the spleen.
•Cold type AIHA is often secondary to other conditions such as lymphoma, leukaemia, systemic lupus erythematosus and infections such as mycoplasma, EBV, CMV and HIV.
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AIHI Ix and Mx
Direct coombs test
Mx:
• Blood transfusions: stop patient becoming to anaemic and having an cardiac arrest
• Prednisolone (steroids): dampen the immune system
• Rituximab (a monoclonal antibody against B cells): destroy B cells producing antibodies
• Splenectomy
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Alloimmune Haemolytic Anaemia
Alloimmune haemolytic anaemia occurs where an there is either foreign red blood cells circulating in the patients blood causing an immune reaction that destroys those red blood cells or there is a foreign antibody circulating in their blood that acts against their own red blood cells and causes haemolysis.
•The two scenarios where this occurs are transfusion reactions and haemolytic disease of the newborn.
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Haemolytic transfusion reactions (antibody produced)
Red blood cells are transfused into the patient.
• The immune system produces antibodies against antigens on those foreign red blood cells.
• This creates an immune response that leads to the destruction of those red blood cells.
• presents a few days after with a blood transfusion
o Immediate (IgM) predominantly intravascular
o Delayed (IgG) predominantly extravascular
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Haemolytic disease of the newborn (Passive transfer of antibody)
• There are antibodies that cross the placenta from the mother to the fetus.
• These maternal antibodies target antigens on the red blood cells of the fetus.
• This causes destruction of the red blood cells in the fetus and neonate.
o Rh D
o ABO incompatibility
o Others eg anti-Kell
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Premature destruction of normal red cells (mechanical)
* Disseminated intravascular coagulation
* Haemolytic uraemic syndrome (e.g. E. coli O157)
* TTP
* Leaking heart valve
* Infections e.g. Malaria
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Microangiopathic Haemolytic Anaemia (MAHA)
small blood vessels have structural abnormalities that cause haemolysis of the blood cells travelling through them.
•Imagine a mesh inside the small blood vessels shredding the red blood cells. This is usually secondary to an underlying condition:
o Haemolytic Uraemic Syndrome (HUS)
o Disseminated Intravascular Coagulation (DIC)
o Thrombotic Thrombocytopenia Purpura (TTP)
o Systemic Lupus Erythematosus (SLE)
o Cancer
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Prosthetic Valve Haemolysis Mx
* Monitoring
* Oral iron
* Blood transfusion if severe
* Revision surgery may be required in severe cases
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Abnormal cell membrane: CAUSES OF HAEMOLYSIS ACQUIRED
• Membrane Defects (all very rare)
o Liver Disease (Zieve’s Syndrome)
o Vitamin E deficiency
o Paroxysmal Nocturnal Haemoglobinuria
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Paroxysmal Nocturnal Haemoglobinuria
rare condition that occurs when a specific genetic mutation in the haematopoietic stem cells in the bone barrow occurs during the patients lifetime.
• The specific mutation results in a loss of the proteins on the surface of red blood cells that inhibit the complement cascade.
• The loss of protection against the complement system results in activation of the complement cascade on the surface of red blood cells and destruction of the red blood cells.
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Paroxysmal Nocturnal Haemoglobinuria signs/symptoms
• red urine in the morning containing haemoglobin and haemosiderin.
anaemic due to the haemolysis
predisposed to thrombosis (e.g. DVT, PE and hepatic vein thrombosis) and smooth muscle dystonia (e.g. oesophageal spasm and erectile dysfunction).
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Paroxysmal Nocturnal Haemoglobinuria Mx
Eculizumab
| Bone marrow transplantation
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Hereditary Spherocytosis
most common inherited haemolytic anaemia in northern Europeans.
• It is an autosomal dominant condition.
• It causes sphere shaped red blood cells that are fragile and easily break down when passing through the spleen.
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Hereditary Spherocytosis signs/symptoms
It presents with jaundice, gallstones, splenomegaly and notably aplastic crisis in the presence of the parvovirus.
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Hereditary Spherocytosis Ix and Mx
family history and clinical features with spherocytes on the blood film.
• The mean corpuscular haemoglobin concentration (MCHC) is raised on a full blood count. Sphere shaped RBC can carry more haemoglobin than a normal haemoglobin
• Reticulocytes will be raised due to rapid turnover of red blood cells.
Mx
•folate supplementation and splenectomy (takes away the filter so RBC last longer).
cholecystectomy
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Hereditary Elliptocytosis
* Hereditary elliptocytosis is very similar to hereditary spherocytosis except that the red blood cells are ellipse shaped.
* It is also autosomal dominant.
* Presentation and management are the same.
106
G6PD deficiency (abnormal cell metabolism)
defect in the red blood cell enzyme G6PD (glucose-6-phosphate dehydrogenase)
more common in Mediterranean and African patients and is X linked recessive.
It causes crises that are triggered by infections, medications or fava beans (broad beans).
107
G6PD deficiency signs/symptoms
Jaundice (usually in the neonatal period), gallstones, anaemia, splenomegaly and Heinz bodies on blood film.
look out for a patient that turns jaundice and becomes anaemic after eating broad beans, developing an infection or being treated with antimalarials. The underlying diagnosis might be G6PD deficiency
108
G6PD Ix and Mx
G6PD enzyme assay
Medications that trigger haemolysis include primaquine (an antimalarial), ciprofloxacin, sulfonylureas, sulfasalazine and other sulphonamide drugs.
109
What are Haemoglobinopathies?
Hereditary conditions affecting globin chain synthesis. autosomal recessive disorders
Two main groups
o Thalassaemias: decreased rate of globin chain synthesis
o Structural haemoglobin variants; normal production of abnormal globin chain → variant haemoglobin eg HbS – sickle
110
Thalassaemia
genetic defect in the protein chains that make up haemoglobin.
Reduced globin chain synthesis resulting in impaired haemoglobin production
111
Major Forms of Haemoglobin
* HbA (2 alpha chains and 2 beta chains; α2β2 )
* HbA2 (2 alpha and 2 delta; α2δ2)
* HbF (2 alpha and 2 gamma; α2γ2)
112
Thalassaemia pathophysiology
* In thalassaemia, the red blood cells are more fragile and break down more easily.
* The spleen acts as a sieve to filter the blood and remove older blood cells.
* In thalassaemia the spleen collects all the destroyed red blood cells and swells, resulting in splenomegaly.
* The bone marrow expands to produce extra red blood cells to compensate for the chronic anaemia.
* This causes a susceptibility to fractures and prominent features such as a pronounced forehead and malar eminences (cheekbones).
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Thalassaemia signs/symptoms
* Inadequate Hb production → microcytic hypochromic anaemia
* Fatigue
* Pallor
* Jaundice
* Gallstones
* Splenomegaly
* Poor growth and development
* Pronounced forehead and malar eminences
114
Thalassaemia Ix
• Full blood count shows a microcytic anaemia.
• DNA testing can be used to look for the genetic abnormalities
• Pregnant women in the UK are offered a screening test for thalasseamia at booking.
• Simple things first!
o FBC; Hb, red cell indices
o Blood film
o Ethnic origin
• High performance liquid chromatography (HPLC) or electrophoresis to quantify haemoglobins present
o Identifies abnormal haemoglobins eg HbS
o Raised HbA2 diagnostic of beta thal trait
115
Alpha-thalassaemia
defects in alpha-globin chains.
* The gene coding for this protein is on chromosome 16 (Two alpha genes per chromosome (4 per cell))
* Unaffected individuals have 4 normal α genes (αα/αα)
* Results from deletion of one α+ (-α) or both α0 (--) alpha genes from chromosome 16
* Results in reduced α+ or absent α0 alpha chain synthesis from that chromosome
* α chains present in HbA, HbA2 and HbF therefore all are affected
116
Classification of Alpha thalassaemia
* Unaffected = 4 normal α genes (αα/αα)
* α thalassaemia trait: one or two alpha genes missing, asymptomatic carrier state, microcytic hypochromic red cells but ferritin normal
* HbH disease: only one alpha gene left (--/-α ), moderate to severe anaemia
* Hb Barts hydrops fetalis; no functional α genes (--/--) , incompatible with life
117
HbH Disease
* More severe form of alpha thalassaemia
* Only one working α gene per cell (--/-α )
* Anaemia with very low MCV and MCH
* Excess β chains form tetramers (β4) called HbH
* Red cell inclusions of HbH can be seen with special stains: golf ball like
* Jaundice, splenomegaly, may need transfusion
118
Hb Barts Hydrops Foetalis Syndrome
* Severest form of α thalassaemia
* No α genes inherited from either parent (--/--)
* Minimal or no α chain production →HbF and HbA can’t be made
* No alpha chains to bind to so tetramers of Hb Barts (γ4) and HbH (β4) produced
* Possible risk if both parents from SE Asia where α0 (--) thal trait prevalent
* Profound anaemia
* Cardiac failure
* Growth retardation
* Severe hepatosplenomegaly
* Skeletal and cardiovascular abnormalities
* Almost all die in utero
* Film shows numerous nucleated RBCs in peripheral blood
119
Alpha thalassaemia Mx
* No management needed for alpha thalassaemia trait
* Antenatal screening to avoid risk
* Monitoring the full blood count
* Monitoring for complications
* Blood transfusions
* Splenectomy may be performed if severe splenomegaly or anaemia
* Bone marrow transplant can be curative
120
Beta-thalassaemia
Defects in beta-globin chains synthesis.
• The gene coding for this protein is on chromosome 11. One beta gene per chromosome (2 per cell)
• Reduced ( β+), or absent ( β0 ) beta chain production depending on the mutation
• Only β chains and hence only HbA (α2β2) affected
121
Thalassaemia minor (β+/β or β0/β)
* Patients with beta thalassaemia minor are carriers of an abnormally functioning beta globin gene. They have one abnormal and one normal gene.
* Thalassaemia minor causes a mild microcytic anaemia and usually patients only require monitoring and no active treatment.
* low MCV/MCH, raised HbA2 diagnostic
122
Thalassaemia intermedia (β+/β+ or β0/β+)
two abnormal copies of the beta-globin gene.
• This can be either two defective genes or one defective gene and one deletion gene.
• Thalassaemia intermedica causes a more significant microcytic anaemia and patients require monitoring and occasional blood transfusions.
• If they need more transfusions they may require iron chelation to prevent iron overload.
123
Thalassaemia major (β0/β0)
homozygous for the deletion genes (two copies of deletion gene).
• They have no functioning beta-globin genes at all.
• This is the most severe form and usually presents with severe anaemia and failure to thrive in early childhood.
Thalassaemia major causes:
o Severe microcytic anaemia
o Splenomegaly
o Bone deformities resulting in skeletal changes and organ damage
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Thalassaemia major (β0/β0) Ix and Mx
Haemoglobin analysis: HbF and no HbA
Blood film: distorted blood cells
Mx
• Regular transfusion programme to maintain Hb at 95-105g/l
o Suppresses ineffective erythropoiesis and ease off issues like jaundice
o Inhibits over-absorption of iron
• Allows for normal growth and development
• Iron overload from transfusion then becomes the main cause of mortality
- iron chelation
* splenectomy
* Bone marrow transplant may be an option if carried out before complications develop
125
Iron overload pathology thalassaemia
occurs in thalassaemia as a result of faulty creation of red blood cells, recurrent transfusions and increased absorption of iron in response to the anaemia.
126
Iron overload Ix and Mx
serum ferritin levels monitored to check for iron overload.
Management involves limiting transfusions and iron chelation e.g. desferrioxamine
127
Haemochromatosis Ix
* Risk of iron loading: transferrin saturation >50% (sustained on repeat fasting sample)
* Increased iron stores: serum ferritin >300 mg/l in men or >200 mg/l in pre-menopausal women
128
Haemochromatosis Mx
Weekly venesection
o 450-500ml
o 200-250mg iron
Initial aim to exhaust iron stores (ferritin <20 µg/l)
Thereafter keep ferritin below 50 µg/l
129
Sickle Cell Anaemia
sickle (crescent) shaped red blood cells.
• This makes the red blood cells fragile and more easily destroyed in spleen leading to an haemolytic anaemia.
• Two abnormal β genes (βs/βs)
• HbS > 80%, no HbA
* Episodes of tissue infarction due to vascular occlusion – sickle crisis
* Chronic haemolysis – shortened RBC lifespan
* Sequestration of sickled RBCs in liver and spleen
* Hyposplenism due to repeated splenic infarcts
130
Pathophysiology sickle cell anaemia
* Fetal haemoglobin (HbF) is usually replaced by haemoglobin A (HbA) at around 6 weeks of age.
* Patients with sickle-cell disease have an abnormal variant called haemoglobin S (HbS).
* HbS causes red blood cells to be an abnormal “sickle” shape.
* autosomal recessive condition where there is an abnormal gene for beta-globin on chromosome 11.
* Point mutation in codon 6 of the β globin gene that substitutes glutamine to valine producing bS
* This alters the structure of the resulting Hb→ HbS (α2βs2)
* HbS polymerises if exposed to low oxygen levels for a prolonged period
* This distorts the red cell, damaging the RBC membrane
131
Sickle Cell Trait (HbAS)
* One normal, one abnormal β gene (β/βs)
* Few clinical features as HbS level too low to polymerise
* May sickle in severe hypoxia e.g. high altitude, under anaesthesia
132
Sickle cell anaemia Ix
booking clinic
newborn screening heel prick test at 5 days of age.
FBC; Hb, red cell indices
Blood film: Sickle cell shaped and target cells
Ethnic origin
High performance liquid chromatography (HPLC) or electrophoresis to quantify haemoglobins present
133
Sickle cell anaemia Mx
General management
• Opiate analgesia, rest and O2
• Avoid dehydration and other triggers of crises
• Antibiotic prophylaxis to protect against infection with penicillin V (phenoxymethypenicillin) and vaccinations
• Blood transfusion for severe anaemia
• Red cell exchange transfusion in severe crisis eg (lung) chest crisis or (brain)stroke
o Exchange decreases concentration of HbS and improves tissue perfusion
• Bone marrow transplant can be curative
Long term Mx
• Hyposplenism - reduce risk of infection
o prophylactic penicillin
o vaccination; pneumococcus, meningococcus, haemophilus
• Folic acid supplementation (↑ RBC turnover so ↑demand)
• Hydroxycarbamide can be used to stimulate production of fetal haemoglobin (HbF).
• Regular transfusion to prevent stroke in selected cases
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Vaso-occlusive Crisis (AKA painful crisis)
caused by the sickle shaped blood cells clogging capillaries causing distal ischaemia. It is associated with dehydration and raised haematocrit.
Fever, pain and can cause priapism
Mx: aspiration of blood
135
Splenic Sequestration Crisis
red blood cells blocking blood flow within the spleen. This causes an acutely enlarged and painful spleen
Pooling of blood in spleen: severe anaemia and hypovolaemic shock
Mx
blood transfusion & fluid resus
splenectomy
136
Aplastic crisis
• temporary loss of the creation of new blood cells.
• commonly triggered by infection with parvovirus B19.
significant anaemia
• Management is supportive with blood transfusions if necessary.
• It usually resolves spontaneously within a week.
137
Pancytopenia
deficiency of blood cells of all lineages
Pancytopenia is NOT a diagnosis (it reflects a diagnosis)
Pancytopenia does NOT always mean bone marrow failure or malignancy
138
Reduction production causes pancytopenia (Primary)
Bone Marrow Failure (Primary)
Acquired
- idiopathic aplastic anaemia: autoimmune attack against hemopoietic stem cells
- Myelodysplastic syndromes
- dysplasia, hypercellular marrow, increased apoptosis of progenitor and mature cells
- Acute leukaemia: AML or ALL
Inherited syndromes:
e.g. Fanconi's anaemia
• Unable to correct inter-strand cross-links (DNA damage)
• Macrocytosis followed by thrombocytopenia, then neutropenia
• Bone marrow failure (aplasia) risk: 84% by 20 years
- AML risk
139
Secondary Bone Marrow Failure: pancytopenia
* Drug induced [e.g. chemotherapy, alcohol, azathioprine, methotrexate chloramphenicol] – causes aplasia: hypocellular
* B12/folate deficiency (nuclear maturation can affect all lineages) (remember hypercellular!)
* Infiltrative- non-haemopoietic malignant infiltration, lymphoma
* Misc.: Viral (eg HIV)/storage diseases
140
Pancytopenia: Increased destruction
Hypersplenism
141
Marrow Cellularity in Pancytopenia
Hypocellular in aplastic anaemia
Hypercellular in Myelodysplastic syndromes, B12/folate deficiency and Hypersplenism
142
Pancytopenia Mx
* Red cell transfusions
* Platelet transfusions
* Antibiotics prophylaxis/treatment: antibiotics and antifungals
* Treat neutropenic fever promptly based on local unit antibiotic policy without waiting for (microbiology) results
143
Leukaemia
Rapidly progressive clonal malignancy of the marrow/blood with increased proliferation but maturation defect(s) (progenitor or stem cells)
```
o Acute myeloid leukaemia
o Acute lymphoblastic leukaemia
o Chronic myeloid leukaemia
o Chronic lymphocytic leukaemia
- acute promyelocytic leukaemia: translocation long arms t(15;17) and is associated with a coagulopathy (DIC)
```
144
Normal Haemopoeiesis vs malignant haemopoiesis
Normal: polyclonal
Malignant: Monoclonal
145
Leukaemia presentation
* Fatigue
* Fever
* Failure to thrive (children)
* Pallor due to anaemia
* Petechiae and abnormal bruising due to thrombocytopenia
* Abnormal bleeding
* Lymphadenopathy
* Hepatosplenomegaly
146
Acute Lymphoblastic Leukaemia (ALL)
malignant disease of primitive lymphoid cells (lymphoblasts). Where there is malignant change in one of the lymphocyte precursor cells.
* It causes acute proliferation of a single type of lymphocyte, usually B-lymphocytes.
* Excessive proliferation of these cells causes them to replace the other cell types being created in the bone marrow, leading to a pancytopenia.
* This is the most common cancer in children and peaks around 2-4 years. Adults >45
147
Acute Lymphoblastic Leukaemia (ALL) signs/symptoms
```
marrow failure (anaemia, infections, bleeding)
• Leukaemic effects: high count with obstruction of circulation (high number of lymphoblasts in circulation), involvement of areas outside the marrow and blood (extra-medullary) e.g. CNS, testis
• Bone pain
```
148
Acute Lymphoblastic Leukaemia (ALL) Dx
• Blood count (reduced and pancytopenia) and blood film shows blast cells (high nuclear: cytoplasmic ratio)
• Coagulation screen: include D dimers (DIC)
• Bone marrow aspirate
- Monotonous large cells with high N:C
- Immunophenotyping
• Cyto/molecular genetics
- Trephine
149
ALL management
Chemo (hickman line) and steroids
Other: Radiotherapy, bone marrow transplant and surgery
CAR-T cell therapy approved for use in the NHS for relapsed/refractory B cell acute lymphoblastic leukaemia in people aged up to 25 years
150
Chronic Lymphocytic Leukaemia
chronic proliferation of a single type of well differentiated lymphocyte, usually B-lymphocytes.
Proliferation of abnormal progenitors but no differentiation/maturation block
151
CLL signs/symptoms and Ix
asymptomatic but it can present with infections, anaemia, bleeding and weight loss.
• It can cause warm autoimmune haemolytic anaemia: drop in Hb
• CLL can transform into high-grade lymphoma. This is called Richter’s transformation.
Ix:
•Blood film shows “smear” or “smudge” cells
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CLL Mx
Rituximab
- Ofatumunab and Obinutumab in less fit patients alongside chlorambucil (chemo)
•Targeting malignant B cells (eg ibrutinib and venetoclax in Chronic Lymphocytic Leukaemia, Mantle cell lymphoma)
153
Chronic Myeloid Leukaemia
Proliferation of myeloid cells: Granulocytes and their precursors and other lineages (platelets)
three typical phases: the chronic phase with intact maturation (3-5 years), the accelerated phase and the blast ‘crisis’ phase (reminiscent of acute leukaemia with maturation defect)
cytogenetic change that is characteristic of CML is the Philadelphia chromosome, which is a translocation of genes between chromosome 9 and 22: it is a t(9:22) translocation. The gene product is a tyrosine kinase which causes abnormal phosphorylation (signalling) leading to the haematological changes in CML
154
CML signs/symptoms
chronic phase can last around 5 years, is often asymptomatic and patients are diagnosed incidentally with a raised white cell count.
The accelerated phase occurs where the abnormal blast cells take up a high proportion of the cells in the bone marrow and blood (10-20%). The patients become more symptomatic, develop anaemia and thrombocytopenia and become immunocompromised.
The blast phase follows the accelerated phase and involves an even high proportion of blast cells and blood (>30%). This phase has severe symptoms and pancytopenia. It is often fatal.
• Splenomegaly
• Hypermetabolic symptoms
• Gout
• Misc: Problems related to hyperleucocytosis problems, Priapism
155
CML Ix
Hb decreased
o leucocytosis with neutrophilia and myeloid precursors (myelocytes), eosinophilia, basophilia
o thrombocytosis,
156
CML Mx
Tyrosine kinase inhibitors (eg Imatinib)
BM Transplant
157
Acute Myeloid Leukaemia
* Proliferation of abnormal progenitors with block in differentiation/maturation
* It can be the result of a transformation from a myeloproliferative disorder such as polycythaemia ruby vera or myelofibrosis.
158
AML signs/symptoms
similar to ALL (marrow failure): symptoms related to anaemia, infections or bleeding
• Subgroups of AML may have characteristic presentation
o Coagulation defect - DIC in acute promyelocytic leukaemia (15,17)
o Gum infiltration
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AML Dx
Blood film: blast cells and auer rods
* Blood count (reduced and pancytopenia) and blood film shows blast cells (high nuclear: cytoplasmic ratio)
* Coagulation screen: include D dimers (DIC)
Bone marrow aspirate a
- morphology
- immunophenotyping: CD 23
Cytogenetics
Trephine
Triph
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AML Mx
2-4 cycles of chemotherapy (5-10 days of chemotherapy followed by 2-4 weeks of recovery)
Other: radio, bone marrow transplant and surgery
161
Chemo complications
```
anaemia, thrombocytopenpenia and neutropenia
• Failure
• Stunted growth and development in children
• Neurotoxicity
• Infertility: anthracyclines
• Secondary malignancy
• Cardiotoxicity
• Tumour lysis syndrome
```
162
Tumour Lysis Syndrome
release of uric acid from cells that are being destroyed by chemotherapy (too quick)
• The uric acid can form crystals in the interstitial tissue and tubules of the kidneys and causes acute kidney injury.
• Allopurinol or rasburicase are used to reduce the high uric acid levels.
Monitor calcium and phosphate and K+ as well
163
Lymph node cells and where they live
B cells: associated with follicles and germinal centres (intrafollicular)
Plasma cells: Medulla
T cells?
164
Lymphadenopathy: INDAM
```
•I–Infectious/inflammatory
o bacterial (regional)
o viral (generalised)
```
• N – Neoplastic
o metastatic malignancy
o lymphoma
• D – Drugs/toxins
o Drug-induced hypersensitivity syndrome
* A – Autoimmune
* M – Metabolic
165
Specific lymphoma symptoms
B symptoms: Fever or night sweats or weight loss – (10% over a 6-month period)
Itch without rash, alcohol-induced pain (Hodgkin lymphoma)
166
Hodgkins lymphoma risk factors
* Immunosuppression (e.g. HIV, inherited immunodeficiency states)
* Epstein-Barr Virus
* Autoimmune conditions such as rheumatoid arthritis and sarcoidosis
* Family history
167
Hodgkins lymphoma signs/symptoms
Lymphadenopathy
non-tender and feel “rubbery”.
• Some patients will experience pain in the lymph nodes when they drink with alcohol.
• B symptoms are the systemic symptoms of lymphoma:
o Fever
o Weight loss (10% over a 6 month period)
o Night sweats
```
Fatigue
• Cough
• Shortness of breath
• Abdominal pain
• Recurrent infections
• Relevant to compression, infiltration/extranodal disease: renal failure, superior vena cava obstruction, effusions, marrow failure (some, not all)
```
168
Hodgkins lymphoma Ix
LDH: often raised but non-specific
Lymph node biopsy: Reed-Sternberg cell (abnormally large B cells that have multiple nuclei that have nucleoli inside them: owl with large eyes)
CT/MRI and PET: diagnosing and staging lymphoma
169
Ann Arbor Staging
o Stage 1: Confined to one region of lymph nodes.
o Stage 2: In more than one region but on the same side of the diaphragm (either above or below): 2 or more lymph nodes
o Stage 3: Affects lymph nodes both above and below the diaphragm: 2 or more on both sides
o Stage 4: Widespread involvement including non-lymphatic organs such as the lungs or liver.
170
Hodgkins lymphoma Mx
* Multi-agent Chemotherapy and radiotherapy (aim to cure)
* Chemotherapy creates a risk of leukaemia and infertility.
* Radiotherapy creates a risk of cancer, damage to tissues and hypothyroidism.
* Bleomycin in treatment can cause pneumonitis
* Immunotherapy/stem cell transplantation an option for patients not responding to chemotherapy
171
Burkitt lymphoma
t(8, 14) is associated with Epstein-Barr virus, malaria and HIV.
Fastest growing human tumour. B cells
Chromosomal translocations involving c-myc
High cure rates in high income countries – beware of tumour lysis at the start
172
MALT lymphoma
mucosa-associated lymphoid tissue, usually around the stomach. It is associated with H. pylori infection (B cells in marginal zone of the MALT)
173
Diffuse large B cell lymphoma
often presents as a rapidly growing painless mass in patients over 65 years. Common high grade NHL
Myc-re
174
Mantle
is a rare type of non-Hodgkin lymphoma (NHL). It develops when B-cells (also called B-lymphocytes) become abnormal. B-cells are white blood cells that fight infection. The abnormal B-cells (lymphoma cells) usually build up in lymph nodes, but they can affect other parts of the body.
175
Follicular
B cell: same as above t(14,18)
176
Non-Hodgkin lymphoma's risk factors
* HIV
* Epstein-Barr Virus
* H. pylori (MALT lymphoma)
* Hepatitis B or C infection
* Exposure to pesticides and a specific chemical called trichloroethylene used in several industrial processes
* Family history
177
Non-Hodgkin lymphoma's Mx
o Watchful waiting
o Multi-agent Chemotherapy +/- radiotherapy –risks of neutropenia, cardiotoxicity (also in Hodgkin lymphoma)
o Monoclonal antibodies
Rituximab (CD20) in B cell NHL
Brentuximab (CD30) in T cell NHL
o Stem cell transplantation
• CAR-T cell therapy approved for use in the NHS for relapsed/refractory diffuse large B cell lymphoma and primary mediastinal B cell lymphoma (types of high grade B cell non-Hodgkin’s lymphoma)
178
Myeloma
Cancer of plasma cells and affects multiple areas of body
179
Immunoglobulin type most common in myeloma?
IgG
180
Myeloma signs/symptoms
anaemia, neutropenia and thrombocytopenia (bone marrow infiltration)
* C – Calcium (elevated)
* R – Renal failure
* A – Anaemia (normocytic, normochromic) from replacement of bone marrow.
* B – Bone lesions/pain
181
Myeloma Ix
anyone over 60 with persistent bone pain, particularly back pain, or an unexplained fractures. Perform initial investigations:
o FBC (low white blood cell count in myeloma)
o Calcium (raised in myeloma)
o ESR (raised in myeloma)
o Plasma viscosity (raised in myeloma)
o If any of these are positive
o B – Bence–Jones protein (request urine electrophoresis)
o L – Serum‑free Light‑chain assay
o I – Serum Immunoglobulins
o P – Serum Protein electrophoresis
Bone marrow biopsy
MRI: Bony lesions
182
Myeloma Mx
• First line treatment usually involves a combination of chemotherapy with:
o Dexamethasone
o Alkylating agents: cyclophosphamide, melphalan
o 'Novel agents' like thalidomide, bortezomib and lenalidomide
o Monoclonal antibodies: daratumumab: blocks CD38
o High dose chemotherapy/autologous stem cell transplant in fit patients
183
Management Myeloma Bone Disease
Bisphosphonates
Radiotherapy
Orthopaedic surgery
Cement augmentation
184
Monoclonal gammopathy of undetermined significance (MGUS)
excess of a single type of antibody or antibody components without other features of myeloma or cancer.
can progress to myeloma
```
• Paraprotein <30g/l
• Bone marrow plasma cells <10%
• No evidence of myeloma end organ damage;
o Normal calcium
o Normal renal function
o Normal haemoglobin
o No lytic lesions
o No increase in infections
```
185
Waldenstrom’s Macroglobulinaemia (IgM paraprotein)
• Smouldering myeloma is where there is progression of MGUS with higher levels of antibodies or antibody components.
o It is premalignant and more likely to progress to myeloma than MGUS.
o Waldenstrom’s macroglobulinemia is a type of smouldering myeloma where there is excessive IgM specifically.
Lymphoplasmaytodoid neoplasm - intermediate between a lymphocyte and a plasma cell - IgM
186
Clinical features of Waldenstroms
```
• Hyperviscosity syndrome
o Fatigue, visual disturbance, confusion, coma
o Bleeding
o Cardiac failure
• B symptoms; night sweats, weight loss
```
187
Waldenstroms Mx
* Chemotherapy
* Protease inhibitor: Bortezomib
* Plasmapheresis (removes paraprotein from the circulation)
188
Myeloproliferative disorders
* Myelo = bone marrow lineage(s) (granulocytes, red cells & platelets)
* Proliferative = to grow or multiply by rapidly producing new tissue, parts, cells, or offspring
* These conditions occur due to uncontrolled proliferation of a single type of stem cell. Clonal haemopoietic stem cell disorders with an increased production of one or more types of haemopoietic cells
In contrast to leukaemia, maturation is reserved
189
Myeloproliferative disorders types
o Primary myelofibrosis: result of proliferation of the hematopoietic stem cells
o Polycythaemia vera: result of proliferation of the erythroid cell line
o Essential thrombocythaemia: result of proliferation of the megakaryocytic cell line.
190
Myelofibrosis
Myelofibrosis can be the result of primary myelofibrosis, polycythaemia vera or essential thrombocythaemia.
* Myelofibrosis is where the proliferation of the cell line leads to fibrosis of the bone marrow.
* The bone marrow is replaced by scar tissue.
* This is in response to cytokines that are released from the proliferating cells. One particular cytokine is fibroblast growth factor.
* This fibrosis affects the production of blood cells and can lead to anaemia and low white blood cells (leukopenia).
* When the bone marrow is replaced with scar tissue the production of blood cells (haematopoiesis) starts to happen in other areas such as the liver and spleen.
* This is known as extramedullary haematopoiesis and can lead to hepatomegaly and splenomegaly.
* This can lead to portal hypertension.
* If it occurs around the spine it can lead to spinal cord compression (need urgent MRI)
191
MPN signs/symptoms
• Initially, myeloproliferative disorders can be asymptomatic.
• They can present systemic symptoms:
• Fatigue
• Weight loss
• Night sweats
• Fever
• There may be signs and symptoms of underlying complications:
o Anaemia (except in polycythaemia)
o Splenomegaly (abdominal pain)
o Portal hypertension (ascites, varices and abdominal pain)
o Low platelets (bleeding and petechiae)
o Thrombosis is common in polycythaemia and thrombocythaemia
o Raised red blood cells (thrombosis and red face)
o Low white blood cells (infections)
192
Primary Myelofibrosis signs/symptoms
* marrow failure: anaemia, bleeding, infection
* splenomegaly: Complications including portal hypertension
* hypercatabolism
193
Primary Myelofibrosis or secondary Ix
FBC: anaemia, o Leukocytosis or leukopenia (high or low white cell counts), Thrombocytosis or thrombocytopenia (high or low platelet counts)
Blood film: teardrop shaped RBC (poikilocytes) and immature red & white cells (blasts) and leukoerythroblastic film appearances
Bone marrow biopsy
Tetsing for JAK2, MPL and CALR genes
194
Primary Myelofibrosis Mx
• Patients with mild disease with minimal symptoms might be monitored and not actively treated.
• Supportive care (blood transfusion, platelets, antibiotics)
• Allogeneic stem cell transplantation is potentially curative but carries risks.
• Chemotherapy can help control the disease, improve symptoms and slow progression but is not curative on its own.
• Supportive management of the anaemia, splenomegaly and portal hypertension.
o Splenectomy (CONTROVERSIAL)
o JAK2 inhibitors (improve spleen size, constitutional symptoms, ?survival: not best evidence for this)
195
Polycythaemia Vera (PV)
High haemoglobin/haematocrit accompanied by erythrocytosis (a true increase in red cell mass) but can have excessive production of other lineages
Distinguish from
o secondary polycythaemia (chronic hypoxia, smoking, erythropoietin-secreting tumour etc)
o pseudopolycythaemia (eg dehydration, diuretic therapy, obesity)
196
Polycythaemia Vera (PV) signs/symptoms
• Clinical features common to MPN
• Headache, fatigue
• Itch (aquagenic puritis)
• Thrombosis is common in polycythaemia and thrombocythaemia
• Raised red blood cells (thrombosis and red face)
o Conjunctival plethora (excessive redness to the conjunctiva in the eyes)
o A “ruddy” complexion
o Splenomegaly
197
PV Ix
Examination
JAK2 mutation: loss of autoinhibition and activation of erythropoiesis
FBC and blood film
Raised Hb (185 - men and 165 female)
* Investigation for secondary/pseudo causes (CXR, O2 saturation/arterial blood gases, drug history)
* Infrequent tests: erythropoietin levels, bone marrow biopsy
198
Management of Polycythaemia Vera
* Venesection to haematocrit <0.45 can be used to keep the haemoglobin in the normal range. This is the first line treatment.
* Aspirin can be used to reduce the risk of developing blood clots (thrombus formation).
* Cytotoxic oral chemotherapy (eg Hydroxycarbamide): HCT and PLT – it is very well tolerated despite being chemotherapy
199
Essential Thrombocytopenia
• Uncontrolled production of abnormal platelets
• Platelet function abnormal
o thrombosis
o at high levels can also cause bleeding due to acquired von Willebrand disease (absorbed onto the surface of platelets and reducing the levels)
200
ET Dx
```
• Exclude reactive thrombocytosis (Blood loss, inflammation, malignancy, iron deficiency)
• Primary Thrombocythaemia: Raised platelet count (more than 600 x 109/l)
• Exclude CML
• Genetics:
o JAK2 mutations in approx. 50 - 60%
o CALR (Calreticulin) in approx. 25%
o MPL mutation in approx. 5%
• Characteristic bone marrow appearances
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ET Mx
Aspirin (blood clots - prevent)
• Cytoreductive therapy to control proliferation
o hydroxycarbamide, anagrelide, interferon alpha
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Myelodysplastic syndrome
• caused by the myeloid bone marrow cells not maturing properly and therefore not producing healthy blood cells.
• It causes low levels of blood components that originate from the myeloid cell line:
o Anaemia
o Neutropenia (low neutrophil count)
o Thrombocytopenia (low platelets)
• It is more common in patients above 60 years of age and in patients that have previously had treatment with chemotherapy or radiotherapy (damaged the bone marrow).
• There is an increased risk of transforming into acute myeloid leukaemia
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Myelodysplastic syndrome signs/symptoms and Ix
anaemia (fatigue, pallor or shortness of breath), neutropenia (frequent or severe infections) or thrombocytopenia (purpura or bleeding).
Full blood count will be abnormal. There may be blasts on the blood film.
• The diagnosis is confirmed by bone marrow aspiration and biopsy.
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Myelodysplastic syndrome Mx
o Watchful waiting
o Supportive treatment with blood transfusions if severely anaemic
o Chemotherapy
o Stem cell transplantation
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Cytotoxic drug classification
•Cell cycle specific
o Tumour specific (relatively): preferentially target more rapidly dividing cells
o Duration of exposure more important than dose
Non-cell cycle specific
o Non-tumour specific; damage normal stem cells
o Cumulative dose more important than duration
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Cytotoxic drugs: general side effects (immediate)
• Affects rapidly dividing organs
o Bone marrow suppression
o Gut mucosal damage
o Hair loss (alopecia)
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Cytotoxic drugs: examples of drug specific side effects
* Vinca alkaloids: neuropathy
* Anthracyclines: cardiotoxicity
* Cis-platinum: nephrotoxicity
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Cytotoxic drugs: long term side effects
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• Alkylating agents
o Infertility: especially younger patients
o Secondary malignancy
• Anthracyclines
o Cardiomyopathy
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Supportive therapy during chemo
* Prompt treatment of neutropenic fever/infection.
* Broad Spectrum antibiotics.
* Prophylactic antifungal drugs e.g. itraconazole or posaconazole
* Red cell and platelet transfusion.
* Growth Factors (GCSF): to prevent neutropenia during chemotherapy cycles
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Haemostasis
Haemostasis: The arrest of bleeding and the maintenance of vascular patency
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Components of Normal Haemostatic System
* Primary Haemostasis: Formation of platelet plug
* Secondary Haemostasis: Formation of fibrin clot
* Fibrinolysis: when haemostasis is secure, body then starts breaking down to restore blood supply
* Anticoagulant Defences: Protein C and S and antithrombin
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Failure of Platelet Plug Formation - causes
Vascular:
o Old age: Vessel wall - Loss of collagen, or scurvy (vitamin C)
o Hereditary: Marfans: hyperflexibility – bleeding tendency (collagen)
o Acquired: Vasculitis e.g. Henoch-Schonlein Purpura
• Platelets
o Reduced number (thrombocytopenia)
o Reduced function
•Von Willebrand Factor: deficient and inherited
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Consequences of failure of Platelet Plug Formation
* Spontaneous Bruising and Purpura
* Mucosal Bleeding e.g. Epistaxes, Gastrointestinal, Conjunctival & Menorrhagia
* Intracranial haemorrhage
* Retinal haemorrhages
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Formation of fibrin clot
* Platelet plug (full of phospholipid): normally negative charge but it releases calcium on to its surface & makes it positive
* Clotting factors are negative – carboxyl groups and they sit on the surface
* Localised response and a site of injury
* Tissue factor is released and binds to clotting factor TF/VII
* They activate V/Xa – activates prothrombin and in turn thrombin – fibrinogen and the end fibrin clot
* Only small amount of TF/VIIa therefore would be a small clot. So when thrombin is formed – activates in VIII/IXa and in turn activates more V/Xa – small positive feedback loop
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Failure of Fibrin Clot Formation - causes
• Single clotting factor deficiency e.g. Haemophilia (A: VIII & B: IX)
Multiple clotting factor deficiencies
o usually acquired e.g. DIC
o Liver failure
o Vitamin K Deficiency/Warfarin therapy (antagonizes 2,7, 9 and 10)
Increased fibrinolysis
o usually part of complex coagulopathy
o Use up clotting factors – usually associated with DIC
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single clotting and multiple clotting: PT and APTT
Single clotting:
o VIII: activated partial thromboplastin prolonged and Prothrombin time normal
o VII: activated partial thromboplastin normal and Prothrombin time raised
Multiple:
o Both sides will be prolonged
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Thrombocytopenia: Problems with Production (problems with bone marrow)
* Sepsis
* B12 or folic acid deficiency
* Liver failure causing reduced thrombopoietin (stimulates platelet production) production in the liver
* Leukaemia
* Myelodysplastic syndrome
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Thrombocytopenia: problems with destruction
* Medications (sodium valproate, methotrexate, isotretinoin, antihistamines, proton pump inhibitors)
* Coagulopathy e.g. Disseminated intravascular coagulation
* Alcohol
* Autoimmune: Immune thrombocytopenic purpura
* Thrombotic thrombocytopenic purpura
* Heparin-induced thrombocytopenia
* Haemolytic-uraemic syndrome
* Hypersplenism
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Immune Thrombocytopenic Purpura (ITP): also called autoimmune thrombocytopenic purpura, idiopathic thrombocytopenic purpura and primary thrombocytopenic purpura
Antibodies are created against platelets. This causes an immune response against platelets, resulting in the destruction of platelets and a low platelet count.
Mx
• Prednisolone (steroids)
• IV immunoglobulins
• Rituximab (a monoclonal antibody against B cells)
-Splenectomy
-The platelet count needs to be monitored
-Additional measures such as carefully controlling blood pressure and suppressing menstrual periods are also
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Thrombotic Thrombocytopenic Purpura
tiny blood clots develop throughout the small vessels of the body using up platelets and causing thrombocytopenia, bleeding under the skin and other systemic issues.
• It affect the small vessels so it is described as a microangiopathy.
• The blood clots develop due to a problem with a specific protein called ADAMTS13.
• This protein normally inactivates von Willebrand factor and reduces platelet adhesion to vessel walls and clot formation.
• A shortage in this protein leads to von Willebrand factor overactivity and the formation of blood clots in small vessels.
• This causes platelets to be used up leading to thrombocytopenia.
• The blood clots in the small vessels break up red blood cells, leading to haemolytic anaemia.
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Thrombotic Thrombocytopenic Purpura Mx
plasma exchange, steroids and rituximab (a monoclonal antibody against B cells)
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Heparin Induced Thrombocytopenia
development of antibodies against platelets in response to exposure to heparin.
• These heparin induced antibodies specifically target a protein on the platelets called platelet factor 4 (PF4).
• These are anti-PF4/heparin antibodies.
• The HIT antibodies bind to platelets and activate clotting mechanisms.
• This causes a hypercoagulable state and leads to thrombosis.
• They also break down platelets and cause thrombocytopenia.
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Von Willebrand Disease vWF Deficiency
Isolated prolonged APTT and normal PT: carries factor VIII (therefore destruction of VIII)
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Vit K: factors
Factors II, VII, IX & X are carboxylated by vitamin K which is essential for function
225
Vit K deficiency causes
* Poor dietary intake
* Malabsorption: Crohns
* Obstructive jaundice: Bile salts can’t get released and absorb vitamin K
* Vitamin K antagonists (warfarin)
* Haemorrhagic disease of the newborn: haven’t got leafy green veg in your diet and none in breastmilk. Newborn, no bowel bacteria
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Disseminated Intravascular Coagulation
• Excessive and inappropriate activation of the haemostatic system
o Primary, secondary and fibrinolysis
• systemic activation of the coagulation system followed by activation of fibrinolytic system
• high thrombin and plasmin generation
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Causes
• Sepsis
• Obstetric emergencies e.g. placental abruption or intrauterine death
• Malignancy
• Hypovolaemic shock
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DIC signs/symptoms
• Microvascular thrombus formation – blocks small vessels
o end organ failure – kidneys and brain failure
o fibrinolysis to open up the blood vessels
• Clotting factor consumption
o Bruising, purpura and generalised bleeding
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DIC Ix and Mx
prolonged prothrombin time and prolonged activated partial thromboplastin time
DIC: Excess fibrinolysis: see very high levels of D dimers
Mx
- Platelet transfusions
- Plasma transfusions e.g. cryoprecipitate
- fibrinogen replacement
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Haemophilia
X-linked, hereditary disorder in which abnormally prolonged bleeding recurs episodically. Not affecting primary haemostasis
* Haemophilia A is caused by a deficiency in factor VIII.
* Haemophilia B (also known as Christmas disease) is caused by a deficiency in factor IX.
* Both haemophilia A and B are X linked recessive.
* Haemophilia A is 5 times more common than B
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Haemophillia signs/symptoms
• It can present with intracranial haemorrhage, haematomas and cord bleeding in neonates.
• Spontaneous bleeding into joints (haemoathrosis) and muscles are a classic feature of severe haemophilia and worth remembering for your exams.
• Abnormal bleeding can occur in other areas:
o Gums
o Gastrointestinal tract
o Urinary tract causing haematuria
o Retroperitoneal space
o Intracranial
o Following procedures
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Haemophillia Ix and Mx
Isolated prolonged APTT and normal Prothrombin
Mx
• The affected clotting factors (VIII or IX) can be replaced by intravenous infusions.
• This can be either prophylactically or in response to bleeding.
• Acute episodes of bleeding or prevention of excessive bleeding during surgical procedures involve:
o Infusions of the affected factor (VIII or IX)
o Desmopressin to stimulate the release of von Willebrand Factor
o Antifibrinolytics such as tranexamic acid
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Thrombophilias
Familial or acquired disorders of the haemostatic mechanism which are likely to predispose to thrombosis.
```
• Increased tendency to develop venous thrombosis (deep vein thrombosis/pulmonary embolism)
o Antiphospholipid syndrome (acquired)
o Antithrombin deficiency: Less efficient switching off and therefore more likely to form fibrin clots
o Protein C or S deficiency
o Factor V Leiden
o Hyperhomocysteinaemia
o Prothrombin 20210 mutation
o Activated protein C resistance
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Anti-thrombin naturally neutralises what clotting factors
serine protease enzymes including thrombin, factor Xa, VIIa and IXa
234
Protein C and S: clotting factors
Factors V and VIII
235
Management of Hereditary Thrombophilia
* Advice on avoiding risk e.g. COC increasing oestrogen
* Short term prophylaxis: to prevent thrombotic events during periods of known risk e.g. hospital - enozaparin (LMWH) and TED stockings
* Short term anticoagulation: to treat thrombotic events
* Long term anticoagulation: if recurrent thrombotic events
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VTE and not provoked?
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To screen for cancer they recommend:
o History and examination
o Chest X-ray
o Bloods (FBC, calcium and LFTs)
o Urine dipstick
o CT abdomen and pelvis in patients over 40
o Mammogram in women over 40
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Anti-phospholipid antibodies
• In patients with an unprovoked VTE with a family history of VTE they recommend testing for hereditary thrombophilias:
o Factor V Leiden (most common hereditary thrombophilia)
o Prothrombin G20210A
o Protein C
o Protein S
o Antithrombin
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Budd-Chiari Syndrome
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• where a blood clot (thrombosis) develops in the hepatic vein, blocking the outflow of blood.
acute hepatitis
• It presents with a classic triad of:
o Abdominal pain
o Hepatomegaly
o Ascites
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* anticoagulation (heparin or warfarin)
* investigating for the underlying cause of hyper-coagulation
* treating the hepatitis
238
Features of Antiphospholipid Antibody Syndrome
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• Recurrent thromboses
o Arterial, including TIAs
o Venous
• Recurrent fetal loss
• Mild thrombocytopenia
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• Isolated prolonged APTT and normal PT:
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Platelet formation
Endothelial (vessel wall) damage exposes collagen, Von Willebrand Factor (VWF), and other proteins to which platelets have receptors – platelet adhesion at the site of injury.
o Platelets bind to subendothelial collagen via Glycoprotein 1b and Von Willebrand Factor.
o Platelets attach to each other via GPIIb/IIIa and fibrinogen. At the same time……...
• Platelets alter their shape to expose more phospholipid on the surface-provides a greater surface area for coagulation activation and fibrin production to stabilise the clot.
• Process is augmented by release of granules that further stimulate platelet activation eg Thrombin, Thromboxane A2 and ADP in order to recruit more platelets to the process.
• This occurs via receptors to ADP etc on the platelet surface.
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Aspirin
```
Inhibits cyclo-oxygenase which is necessary to produce Thromboxane A2 (a platelet agonist released from granules on activation).
o Bleeding
o Blocks production of prostaglandins:
GI ulceration
Bronchospasm
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241
Clopidogrel, prasugrel
ADP receptor antagonists
242
Dipyridamole
Phosphodiesterase inhibitor -reduces production of cAMP which is a ‘second messenger’ in platelet activation
243
GP IIb/IIIa inhibitors eg abciximab - inhibit aggregation
o Platelets attach to each other via GPIIbIIIa and fibrinogen.
244
Heparin : Unfractionated and LMWH
Potentiates antithrombin: detects when haemostasis has been formed
• Anti-thrombin III: Unfractionated heparin binds to AT III and stabilises it and potentiates it. However this needs close monitoring – less predictable
o Thrombin binds to activated factor X and inactivates it
•LMWH: also helps keep the anti-thrombin – factor X complex together – less monitoring, more predictable
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Heparin monitoring
* Activated partial thromboplastin time (APTT) for unfractionated
* Anti-Xa assay for LMWH but usually no monitoring of LMWH is required as more predictable response
246
Warfarin
* Require vitamin K for final carboxylation step essential for function
* Warfarin: Stops production of these when taking warfarin and generation of fibrin clot does not occur
* PT is more sensitive due to shorter half life of factor VII: use this for monitoring
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Warfarin reversal
* No action: INR normal and minor bleeding
* Omit Warfarin dose(s): high INR but bleeding is ok: reduce INR over 2-3 days
* Administer oral Vitamin K: about 6 hours to act. INR over 8 for example
* Administer clotting factors - immediate (factor concentrates):2, 7, 9 and 10 – reserved for life threatening bleeding
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Direct thrombin inhibitors and Direct activated factor X inhibitors
* Direct thrombin inhibitors (dabigatran)
| * Direct activated factor X inhibitors (eg edoxaban, rivaroxaban, apixaban)
