Week 3 - Haematology Flashcards
Describe the different sites of haematopoiesis in the growing foetus?
- 0-2months: Yolk sac
- 2-7months: liver & spleen
- 5-9months: bone marrow
What is the site of haemopoiesis in infants?
Bone marrow (all bones)
What is the site of haemopoiesis in adults?
Bone marrow (vertebrae, ribs, sternum, skull, sacrum, pelvis, ends of femurs)
List the 5 haemopoietic stem cell characteristics?
- Self renewal capacity
- Unspecialised
- Ability to differentiate (mature)
- Rare (1 in 10,000 to 1 in 1 million in bone marrow)
- Quiescent (i.e. not under going cell cycle)
What are 3 locations for haemopoietic stem cells?
- Bone marrow
- Peripheral blood after treatment with G-CSF
- Umbilical cord blood
What are 3 things which can happen to haemopoietic stem cells?
- Self-renewal
- Apoptosis
- Differentiation
What controls stem cell fate?
- A complex interplay of micro- environmental signals (the niche) & internal cues
- Selected Embryonic Patterning Pathways
What is the definition of stroma?
Bone marrow microenvironment that supports the developing haemopoietic cell
What are stromal cells supported by?
Extracellular matrix
Give 5 examples of stromal cells?
- Macrophages
- Fibroblasts
- Endothelial cells
- Fat cells
- Reticulum cells
What are the 2 outcomes for symmetrical division of stem cells?
- Contraction of stem cell numbers
2. Expansion of stem cell numbers
What is the outcome of asymmetrical division of stem cells?
Maintenance of stem cell numbers
List 5 hereditary conditions which impair bone marrow function?
- Thalassaemia
- Sickle cell anaemia
- Fanconi anaemia
- Thrombocytopenia with absent radii
- Hereditary leukaemia (v. rare)
List 10 acquired conditions which impair bone marrow function?
- Aplastic anaemia
- Leukaemia
- Myelodysplasia
- Myeloproliferative disorders
- Lymphoproliferative disorders
- Myelofibrosis
- Metastatic malignancy e.g. breast, prostate
- Infections e.g. TB / HIV
- Drugs and toxins
- Chemotherapy
List the 4 principles of leukaemogenesis?
- Multi-step process
- Neoplastic cell is a haemopoietic stem cell/early myeloid/lymphoid cell
- Dysregulation of cell growth & differentiation
- Proliferation of the leukaemic clone with differentiation blocked at an early stage
What is the definition of leukaemogenesis?
Induction or production of leukemia
Describe the process of leukaemogenesis?
Human stem cell –> (leukaemogenic event) Leukaemia stem cell –> clonogenic leukaemia cells –> Non-clonogenic leukaemia blast cells
When are haematological malignancies & pre-malignant conditions termed “clonal”?
If they arise from a single ancestral cell
What are non malignant lymphoid proliferations?
Polyclonal
Regarding clonal haemopoietic stem cell disorders, what do X chromosome inactivation studies in women with leukaemia show?
Clonal proliferation carries either an active maternal or paternal X chromosome
What are Myeloproliferative Disorders?
Clonal disorders of haemopoiesis leading to increased numbers of one or more mature blood progeny
Give 6 examples of Myeloproliferative Disorders?
- Polycythaemia rubra vera
- Essential thrombocytosis
- Myelofibrosis
- Mastocytosis
- Clonal hypereosinophilic syndromes
- Chronic neutrophilic leukaemia
What mutations are Myeloproliferative Disorders variably associated with?
JAK2V617F & calreticulin mutation
What do Myeloproliferative Disorders have the potential to transform into?
Acute Myeloid leukaemia (AML)
What is the platelet cost for essential thrombocytosis?
> 600x10*9 /L persistently
List 6 clinical features of essential thrombocytosis?
- Continuum with polycythemia rubra vera (PRV)
- Thrombotic complications
- Haemorrhagic complications
- Splenomegaly
- Transformation to PRV/myelofibrosis
- Leukaemic transformation in ~3%
Describe people at low risk of essential thrombocytosis?
Age <40 with no high risk features
How would you treat people at low risk of essential thrombocytosis?
Aspirin or anti-platelet agent
Describe people at intermediate risk of essential thrombocytosis?
Aged 40-60 with no high risk features
How would you treat people at intermediate risk of essential thrombocytosis?
Aspirin ± hydroxycarbamide
Describe people at high risk of essential thrombocytosis?
- Aged >60
- 1 or more high risk features (plt >1500x109/L, previous thrombosis or thrombotic risk factors e.g. diabetes or hypertension)
How would you manage people at high risk of essential thrombocytosis?
- 1st line: hydroxycarbamide + aspirin
- 2nd line: anagrelide + aspirin
What drug is useful in managing high risk essential thrombocytosis in pregnancy?
IFNα
What are 4 other management options for high risk essential thrombocytosis?
- Busulphan
- 32P
- Combination therapy
- JAK2 inhibitors e.g. ruxolitinib
What do JAK2 mutations result in?
Continuous activation of JAK receptor regardless of ligand binding
What is the JAK2 inhibitors Ruxolitinib now approved for?
Use in patients with myelofibrosis with trials ongoing in essential thrombocytosis & Polycythaemia rubra vera
What does Ruxolitinib do?
Inhibits JAK1 & 2
What does Ruxolitinib show in 70-80% of patients?
Reduced splenomegaly & functional improvement
What is the main side effect of Ruxolitinib?
Thrombocytopenia
What are Myelodysplastic syndromes (MDS) characterised by?
Dysplasia & ineffective haemopoiesis in ≥1 of the myeloid series
What may Myelodysplastic syndromes (MDS) be secondary to?
Previous chemotherapy or radiotherapy
Describe Myelodysplastic syndromes (MDS)?
- May have increased myeloblasts
- Multiple sub-types based on morphology and % blasts (WHO classification)
What do the majority of Myelodysplastic syndromes (MDS) result in?
Progressive bone marrow failure
What can some Myelodysplastic syndromes (MDS) progress to?
Acute myeloid leukaemia
Describe Myelodysplastic syndromes (MDS) clinical features?
- Predominantly affects the elderly
- 20% incidental finding on FBC
- 20% present with infections or bleeding
- Majority (70-80%) present with fatigue due to anaemia
What 3 things are Myelodysplastic syndromes (MDS) IPSS risk scores based on?
- BM blasts (%)
- Karyotype
- Cytopenias
List ways to manage Myelodysplastic syndromes (MDS)?
- Blood & platelet transfusion
- Erythropoietin ± granulocyte colony stimulating factor (G-CSF)
- Immunosuppression: anti-thymocyte globulin (ATG)
- Low dose chemotherapy: hydroxycarbamide, low dose cytarabine
- Demethylating agents: azacytidine, an epigenetic therapy
- Intensive chemotherapy
- Allogeneic stem cell transplantation
What may you need to consider when managing Myelodysplastic syndromes (MDS) in younger patients?
Iron chelation
Describe Fanconi anaemia?
- Bone marrow failure may present from birth into adulthood
- Autosomal recessive inheritance
- Currently 7 genetic sub-types FANCA-G
List the 5 characteristics of Fanconi anaemia?
- Somatic abnormalities
- Bone marrow failure
- Short telomeres
- Malignancy
- Chromosome instability
List 6 abnormalities which can stem from Fanconi anaemia?
- Microphthalmia
- GU malformations
- GI malformations
- Mental retardation
- Hearing loss
- CNS e.g. hydrocephalus
What is the main cause of mortality in people with Fanconi anaemia?
Premature bone marrow failure
What is the gold standard therapy for Fanconi anaemia?
Allogeneic stem cell transplant
What are the 3 other options for treatment of Fanconi anaemia?
- Supportive care
- Corticosteroids
- Androgens (oxymethalone)
What do people with Fanconi anaemia need life time surveillance for?
Secondary tumours
What is the future treatment possibilities for Fanconi anaemia?
Gene therapy in future where faulty FANC gene is replaced
What are the 2 different types of stem cell transplants?
- Autologous transplant (“autograft”)- the patients own blood stem cells
- Allogeneic transplant (“allograft”)- any transplant in which the stem cells come from a donor
List the 5 different types of stem cell donors for Allogeneic transplants?
- Syngeneic Transplant (between identical twins)
- Allogeneic Sibling (HLA identical)
- Haplotype identical (half matched family member, usually parent/half matched sibling)
- Volunteer Unrelated (VUD)/Matched Unrelated (MUD)
- Umbilical cord blood
What are the 4 main indications for autologous stem cell transplant?
- Relapsed Hodgkin’s disease
- Non Hodgkin’s lymphoma
- Myeloma
- Leukaemia
What do almost all autografts (autologous stem cell transplant) use?
Mobilised peripheral blood stem cells harvested by apheresis
What do patients receive when getting an autologous stem cell transplant?
- Growth factor (G-CSF) +/- chemotherapy to make stem cells leave the bone marrow
- Mozobil to collect stem cells in patients that failed to mobilise
What 3 things can you use for allogeneic stem cell transplant?
- Peripheral blood stem cells
- Bone marrow
- Umbilical cord blood
What are the 4 main indications for allogeneic stem cell transplant?
- Acute & chronic leukaemias
- Relapsed lymphoma
- Aplastic anaemia
- Hereditary disorders
What does an allograft have the benefit of in malignant disease?
Graft versus leukaemia but at the expense of graft versus host disease
What is the donor registry within the UK called?
The Anthony Nolan Trust donor registry
What are the 2 problems with volunteer unrelated donor (VUD) transplant?
- Increased risk of graft vs host disease compared to family donor (prefer young, male donors)
- Shortage of donors from other ethnic groups apart from caucasian
Describe non-myeloablative stem cell transplant (SCT)?
- Low-dose, less toxic preparative regimens
- Immunosuppression to allow donor cells to engraft, while graft-versus-leukaemia effect eradicates tumour
- Permits use in patients not eligible for conventional SCT
What are the 3 other advances in stem cell transplant (SCT)?
- Non-myeloablative SCT
- Cord blood transplant
- Donor lymphocyte infusion (DLI) after SCT
Describe Donor lymphocyte infusion (DLI) after stem cell transplant (SCT)?
- To prevent/treat relapse after SCT
- Can induce a graft-versus-leukaemia effect
- High rate of graft-versus-host disease (GVHD)
Describe the process of umbilical cord blood transplant?
- Blood stem cells collected from umbilical cord & placenta
- Cells are tissue typed & frozen in liquid nitrogen in cord blood banks for future use
What are the 2 advantages of umbilical cord blood transplant?
- More rapidly available than volunteers unrelated donor
- Less rigorous matching to patient type of patient as immune system naive
What are the 3 disadvantages of umbilical cord blood transplant?
- Small amount (adults often require double cord transplant)
- Slower engraftment
- If relapse, cannot go back for donor lymphocyte infusion
How does graft versus host disease (GvHD) occur?
- Can happen in patients who have received an allogeneic transplant
- New donor’s immune system recognises the host’s body as ‘foreign’ & starts to attack it
What are the 3 most common manifestations of graft versus host disease (GvHD)?
- Skin rash
- Jaundice
- Diarrhoea
Describe the 2 different forms of graft versus host disease (GvHD)?
- ACUTE graft vs host disease: occurs WITHIN the first 100 days of the transplant
- CHRONIC graft vs host disease: occurs AFTER the first 100 days of the transplant.
What is graft versus host disease (GvHD) usually treated with?
Immunosuppressive agents
Describe graft vs leukaemia (GvL)?
- The same cells which cause GvHD, also attack remaining leukaemia cells
- Very effective, esp in patients where a good remission has been difficult to maintain
What 2 other clinical disorders can graft vs leukaemia (GvL) also work in?
- Lymphoma
2. Myeloma
Is there graft vs leukaemia (GvL) in autologous transplant?
NO GvHD & therefore NO GvL resulting in a greater risk of relapse
List the 10 problems with stem cell transplant?
- Limited donor availability (age limit <65 years)
- Mortality 10-50%
- Graft versus Host Disease (GVHD)
- Immunosuppression
- Infertility in both sexes
- Risk of cataract formation
- Hypothyroidism
- Risk of secondary malignancy
- Risk of osteoporosis / avascular necrosis
- Relapse
What is polycythaemia in simple terms?
Too much blood!
What are the 2 major roles of red blood cells?
- CO2 removal
2. O2 delivery from lungs to tissues
What are the 3 locations for CO2 removal?
- Renal tubules
- Lungs
- Red blood cells
Describe the structure of 1 molecule of haemoglobin?
- 4 globin chains (2 alpha, 2 beta)
- 4 Haem groups
What is haemoglobin able to do?
Reversibly bind O2 without undergoing oxidation or reduction
What is another name for oxidised haemoglobin?
Methemoglobin
What is the total body content of iron?
4G
How much iron is stored in bone marrow & red blood cells?
3G
What transports iron in the plasma?
Transferrin (glycoprotein)
Where is Transferrin synthesised?
In hepatocytes
Describe the structure of Transferrin?
- 2 iron binding domains
- 30% saturated with iron
What 4 places does Transferrin delivery iron to?
- All tissues
- Erythroblasts
- Hepatocytes
- Muscle
What is serum ferritin levels directly proportional to?
Reticuloendothelial system (RES) iron
What is 1mmol/l serum ferritin also equal to?
8mg RES Iron
What is the problem with measuring serum ferritin?
Its an acute phase protein (will increase during infection/inflammation) so isn’t always an accurate measure of iron levels
Describe iron loss in males?
1-2mg/day through GI system
Describe iron loss in females?
1-2mg/day through menstrual loss
What is the amount of iron needed daily?
1-2mg/day
Iron homeostasis has no ___________?
Regulated excretory pathway
What hormone controls the release of iron from the gut cell into the plasma?
Hepcidin
Is haem or non-haem iron easier to absorb from gut lumen into the gut cell?
Haem iron is easier
Describe the reticuloendothelial system (RES) storage of iron?
~500mg of iron stored in ferritin/haemosiderin
What is the lifespan of red blood cells?
120 days
How is iron released & recycled from the reticuloendothelial system (RES)?
- Releases iron to transferrin in plasma
- Transferrin-iron taken up via transferrin receptors on erythroblasts, hepatocytes etc.
Describe hepcidin?
- ‘Low iron’ hormone
- Reduces the levels of iron in plasma
- Binds ferroportin & degrades it, reducing iron absorption & decreasing iron release from the RES
What is the likely cause of most Hereditary Haemochromatosis diseases?
Loss of hepcidin
Where is hepcidin synthesised & what does it require?
Synthesised in the liver (this requires expression of HFE)
What is the most common anaemia in the world?
Iron deficiency anaemia (IDA)
Describe the RBC laboratory features of iron deficiency anaemia?
Hypochromic & Microcytic
What are 4 examples of when you would see hypochromic microcytic red blood cells?
- Iron deficiency anaemia
- Thalassaemia
- Anaemia of chronic disease
- Sideroblastic Anaemia (particularly congenital)
What % of transferrin are saturated with iron in iron deficiency anaemia?
<15%
What does a low serum ferritin always indicate?
Low RED iron stores
Describe iron deficiency anaemia in the presence of tissue inflammation?
IDA can occur with normal serum ferritin levels (rheumatoid arthritis & IBD)
List 4 clinical features of iron deficiency anaemia?
- Koilonychia
- Atrophic glossitis (painless)
- Angular stomatitis
- Oesophageal web (plummer vinson syndrome –> dysphagia)
What are 3 causes of iron deficiency anaemia?
- Dietary (premature neonates, adolescent females)
- Malabsorption (coeliacs)
- Blood loss (mensuration)
How do you confirm a diagnosis of iron deficiency anaemia?
Serum ferritin levels
How much blood is lost during menorrhagia (abnormally heavy period)?
> 80mls blood/period
How much blood is lost during pregnancy?
500mg/ baby
What is the golden rule regarding iron deficiency anaemia in males & post menopausal females?
Due to GI blood loss until proven otherwise
When would be the only 2 times that you would do GI investigations in iron deficiency anaemia?
- GI symptoms
2. Blood in stools
What are the 4 different treatment options for iron deficiency anaemia?
- Ferrous sulphate (200mg tablets)
- Ferrous gluconate (300mg tablets)
- IV iron (1G over 2-3hrs)
- Discover cause
What are the 3 main uses for IV iron to treat iron deficiency anaemia?
- Intolerant of oral iron
- Compliance
- Renal anaemia & Erythropoietin replacement
Describe anaemia of chronic disease (ACD)?
- Failure of iron utilisation
- Iron trapped in RES
- Common
What are 3 causes of anaemia of chronic disease (ACD)?
- Infection
- Inflammation
- Neoplasia
What 2 things does chronic renal failure give?
- Anaemia of chronic disease
2. Decreased Erythropoietin
Describe the RBC laboratory features of anaemia of chronic disease (ACD)?
Normochromic normocytic OR hypochromic microcytic
Describe the blood test results for anaemia of chronic disease (ACD)?
- MCV/MCH normal or raised
- ESR raised
- Ferritin normal or raised
- Iron decreased
- TIBC decreased
What does the blood test TIBC stand for?
Total iron-binding capacity
What does the blood test ESR stand for?
Erythrocyte Sedimentation Rate
What does RBC rouleaux mean?
Stacks or aggregations of red blood cells (RBCs) which can occur when the ESR is raised and is a non-specific indicator of the presence of disease
What are the 3 possible causes of anaemia of chronic disease (ACD)?
- RES Iron blockade, iron trapped in macrophages, raised levels Hepcidin
- Reduced Erythropoietin response
- Depressed marrow activity, cytokine marrow
depression
What is the treatment for anaemia of chronic disease (ACD)?
Treat underlying disorder
What is B12/Folate needed for?
- DNA synthesis & nuclear maturation
- Required for all dividing cells
Where is a B12/Folate deficiency first noted in?
Red blood cells
What does a B12/Folate deficiency result in?
Megaloblastic anaemia inititally, but will effect other organs
What are the 2 dietary sources for B12?
- Meat (esp. liver & kidney)
2. Dairy
What is the daily requirement of B12?
1ug/day
Describe the 5 step process of B12 absorption?
- B12 ingested (in form of animal protein)
- B12 released by enzymes/acid in stomach & duodenum
- Intrinsic factor binds to B12
- IF-B12 complex binds to cubulin
- B12 absorbed & binds to transcobalamin in blood
What is cubulin?
Specific receptor for intrinsic factor-B12 complex, found in the ilium
What makes intrinsic factor?
Gastric parietal cells in fundus/body of stomach
How much B12 is lost & why?
1-2ug/day in urine/faeces
What are the dietary sources of folate?
Green veg (destroyed by cooking)
How is Folate absorbed?
- Most small bowel
- No carrier molecule required
For how long is folate stored?
- Few days
- Quickly used up if increased demand (ie. increased cell turnover)
Describe the pathophysiology of folate deficiency?
- Disparity in rate of synthesis of the precursors of DNA (deoxyribonucleoside triphosphates)
- Abnormality of cell division
What are the 2 types of tissues affected by B12 or Folate deficiency?
- Bone marrow
2. Epithelial surfaces (mouth, stomach, small intestine, urinary, female genital tracts)
What is the blood abnormality caused by B12/folate deficiency?
Megaloblastic anaemia (leucopenia, thrombocytopenia)
What are the neurological manifestations of B12 deficiency?
Bilateral peripheral neuropathy or demyelination of
posterior & pyramidal tracts of spinal cord
Clinically what can a Folate deficiency in the 1st 12 weeks of the growing foetus cause?
Can cause neural tube defects
What are the 2 symptoms of B12/Folate deficiency (anaemia/cytopenia)?
- Tired: macrocytic/ megagloblastic anaemia
(common) - Easy bruising: thrombocytopenic (rare)
What are the 2 signs of B12/Folate deficiency?
- Mild Jaundice: haemolysis
- Neurological problems:
nerve disturbance as a result of B12 def, subacute combined degeneration of cord
List the 4 possible causes of B12 deficiency?
- Dietary
- Pernicious anaemia (no intrinsic factor)
- Gastrectomy/ Achlorhydria
- Terminal ileum problem (crohn’s, resection)
What are the 3 possible causes of folate deficiency?
- Dietary
- Extensive small bowel disease (coeliac, severe crohn’s)
- Increased cell turnover (haemolysis, severe skin disorders, pregnancy)
What are the 3 other causes of macrocytosis?
- Reticulocytosis
- Cell wall abnormalities (lipids)
- With anaemia (bone marrow failure syndromes)
What 3 disorders would cause cell wall abnormalities?
- Alcohol
- Liver disease
- Hypothyroidism
What drives erythropoiesis?
Erythropoietin (kidney)
What are the 4 “ingredients” for erythropoiesis?
- Iron
- B12
- Folate
- Minerals
Describe the inherited condition- haemoglobinopathies?
- Relative lack of normal globin chains due to absent genes (thalassaemias)
- Variant (abnormal) globin chain eg sickle cell disease
What 3 things does the severity of haemoglobinopathies?
- Amount of abnormal haemoglobin
- Type of abnormal haemglobin
- Ameliorating factors
Where are global chains produced?
Ribosomes
Where/What controls haemoglobin production?
Mainly at the transcription level & depends on the availablility of haem.
What are the different types of thalassaemias?
- 4 different alpha globin genes (on 2 Ch16)
- 2 different beta globin genes (on 2 Ch11)
List the 5 different alpha gene permutations & how many alphas are missing in each?
- Alpha+ thalassaemia trait (one alpha missing)
- Homozygous alpha+ thalassaemia trait (2 alphas missing)
- Haemoglobin H thalassaemia trait (3 alphas missing)
- Alpha thalassaemia major (4 alphas missing)
- Alpha minor thalassaemia trait (2 alphas missing)
What is the clinical significance of missing one gene in alpha thalassaemia?
Mild microcytosis
What is the clinical significance in missing 2 genes in alpha thalassaemia?
- Microcytosis
- Increased red cell count
- Sometimes very mild (asymptomatic) anaemia
What is the clinical significant in missing 3 genes in alpha thalassaemia?
- Significant anaemia
- Bizarre shaped small red cells (HbH disease)
What is the clinical significance of missing 4 genes in alpha thalassaemia?
Incompatible with life
Describe HbH (haemoglobin H) disease?
- Missing 3 alpha genes
- Lack of alpha chains -> excess beta chains
- Beta chains end up joining together (HbH)
What is needed in HbH (haemoglobin H) disease during periods of stress?
Blood transfusions
What is the level of haemoglobin in HbH (haemoglobin H) disease?
65-75g/l
Describe Beta thalassaemia major?
- Missing both beta globin genes
- Autosomal recessive
- Unable to make adult haemoglobin (HbA)
- Significant dyserythropoiesis
What is the treatment for Beta thalassaemia major?
Transfusion dependent from early life (first couple of years)
What is the most significant haemoglobin variant?
Sickle cell disease
Describe the pathogenesis of sickle cell disease?
- There is a single amino acid substitution on B globin gene at Position 6 on chromosome 11
- Alpha2betaS2 (sickle)
What produces the abnormal haemoglobin sickle (Hb S)?
Glutamine –> Valine
What produces the abnormal haemoglobin C (HbC)?
Glutamine –> Lysine
What 3 things does the rate of Hb S polymerisation depend on?
- Deoxygenation rate
- Hb concentration
- Hb F
What are the 2 clinical results of sickle cell disease?
- Reduced red cell survival (haemolysis)
2. Vaso-occlusion (tissue hypoxia/infarction)
List the 8 multi-system effects sickle cell disease has on the body?
- Brain: Stroke/Moya Moya
- Lungs: Acute Chest syndrome / Pulmonary
Hypertension - Bones: Dactilytis / Osteonecrosis
- Spleen: Hyposplenic
- Kidneys: Loss of concentration/ Infarction
- Urogenital: Priapism
- Eyes: Vascular Retinopathy
- Placenta: IUGR/Fetal loss
What is Moya Moya?
Rare, progressive cerebrovascular disorder caused by blocked tangled arteries at the base of the brain (basal ganglia)
What are the 3 means of treatment for sickle cell disease?
- Precent crisis
- Prompt management of crises
- Bone marrow transplantation
How can you prevent a crisis in sickle cell disease?
- Hydration, Analgaesia, Early intervention
- Prophylactic vaccination & antibiotics
- Folic acid
How can you prompt management of crises in sickle cell disease?
- Oxygen, fluids, analgaesia, antibiotics, specialist care
- Transfusion/Red cell exchange
What is the definition of haemolytic anaemia?
Anaemia related to reduced RBC lifespan (no blood loss or haematinic deficiency)
Give 3 examples of congenital haemolytic anaemia?
- Abnormalities of RBC membrane (Hereditary spherocytosis)
- Hamoglobinopathies
- Abnormalities of RBC enzymes
Describe Hereditary spherocytosis?
- Autosomal dominant
- RBC’s spherocytic & polychromatic
- Jaundice
- Splenomegaly
What is the treatment (if required) for Hereditary spherocytosis?
Splenectomy & hyposplenic prophylaxis
List the 5 causes of a hyposplenic state?
- Encapsulated organism pneumococcus
- Menigococcus
- Haemophilus
- Immunisations
- Long term penicillin V
What is the red cell lifespan for haemolytic anaemia?
<20 days
Describe the haematology results of haemolytic anaemia?
- Decreased Hb
- Increased Reticulocytes
- Increased Bilirubin
- Increased Spleen
In chronic haemolytic states what can the raised bilirubin cause?
Pigment gall stones
Describe the 3 factors of Pyruvate Kinase Deficiency Anaemia?
- Chronic / extravascular haemolytic anaemia
- ATP depletion
- Autosomal recessive
Describe the 3 factors of Glucose 6 phosphate dehydrogenase deficiency?
- Acute episodic intravascular haemolysis
- X linked recessive (only affects males)
- Acute haemolysis from oxidative stress
What are the 3 types of acquired haemolytic anaemia’s?
- Autoimmune
- Isoimmune
- Non immune
What are the 2 types of autoimmune acquired haemolytic anaemia’s?
- Warm type (IgG)
2. Cold type (IgM)
Give an example of an isoimmune acquired haemolytic anaemia?
Haemolytic disease of newborn (HDN)
Give an example of a non-immune acquired haemolytic anaemia?
Fragmentation haemolysis
Describe the 4 factors of cold autoimmune acquired haemolytic anaemia (AIHA)?
- Autoantibody IgM (+complement)
- Mycoplasma infection
- Idiopathic
- IgM has 5 receptors so makes agglutinins with the red cells
Describe the 5 factors of warm autoimmune acquired haemolytic anaemia (AIHA)?
- Autoantibody IgG (+/- complement)
- Idopathic 30%
- Other autoimmune disease
- Lymphoproliferative disorder (NHL/CLL)
- Drug induced
Describe the red blood cells in warm autoimmune acquired haemolytic anaemia (AIHA)?
- Spherocytic
- Polychromatic
What does drug induced acquired haemolytic anaemia (AIHA) cause?
Usually mild haemolysis
What does the immune complex in acquired haemolytic anaemia (AIHA) cause?
Severe haemolysis
Give an example of a drug which induces immune complexes in acquired haemolytic anaemia (AIHA)?
Cephalosporins
What is the purpose of the Direct Coombs test?
To detect antibody (+/- C’) on RBC surface
What 2 occasions is the Direct Coombs Test positive?
- Autoimmune haemolytic anaemia
2. Haemolytic disease of the newborn
What is the purpose of the Indirect Coombs Test?
To detect RBC antibodies in plasma (via crossmatching)
What is the treatment for cold autoimmune acquired haemolytic anaemia (AIHA)?
- Self limiting mycoplasma
- In idiopathic: keep warm
What is the treatment for warm autoimmune acquired haemolytic anaemia (AIHA)?
- Stop any drugs
- Steroids
- Immunosuppression ie. Azathioprine
- Splenectomy
What are the 2 different types of leukaemia’s?
- Lymphoid
2. Myeloid
What is leukaemia?
- “White blood”
- Blood cancer
- Accumulation of abnormal leucocytes in marrow +/- blood +/- other tissues
How is leukaemia acquired through genetic abnormalities & what does this allow for?
- Cell type in which mutation arises likely to be crucial
- Allows diagnostic testing, monitoring, research,
pharmaceutical targeting
Where do the symptoms of chronic leukaemia come from?
Accumulation of cells
Where do the symptoms of acute leukaemia come from?
Marrow failure
What are Myelodysplastic syndromes (MDS)?
- Clonal Blood disorder
- Group of cancers in which immature blood cells in the bone marrow do not mature
List 5 things that characterise Myelodysplastic syndromes (MDS)?
- Failure of effective haemopoiesis (low blood counts)
- Most common in elderly
- ‘Dysplastic’ blood & marrow appearances
- Approx 25% rate of transformation to AML
- Consequences of marrow failure
How can “low risk” vs “high risk” disease in Myelodysplastic syndromes (MDS) be established?
Proportion of blast cells in marrow & cytogenetic profile (MDS vs AML, Blast % cut-off is 20%)
What is the treatment for Myelodysplastic syndromes (MDS)?
- Incurable (other than with stem cell transplant, <65 years)
- Supportive care: consider drug therapy (eg azacitidine)
What are Myeloproliferative disorders (MPDs)?
- Clonal blood disorders
- JAK2 mutation prevalent
- Characterised by “Effective” haematopoiesis
Describe 3 characteristics of “effective haematopoiesis”?
- Too many platelets (Essential Thrombocythaemia)
- Too many red cells (Polycythaemia Vera/ Primary Polycythaemia)
- Too much fibrous tissue (Myelofibrosis)
Describe the outcome & treatment for Essential Thrombocythaemia?
- Good outcome
- Risk of vascular events (aspirin)
- Cytoreduction (Hydroxycarbamide, venesection or interferon)
Describe Acute Leukaemia & the outcomes?
- Clonal disorders
- Blastic proliferation in bone marrow
- Rapid in onset
- Serious compromise of normal marrow elements
- Death within days or weeks if untreated
Give 2 examples of acute lymphoid leukaemia’s?
- T lymphoblastic leukaemia
2. B lymphoblastic leukaemia
Give 4 examples of acute myeloid leukaemia’s?
- Erythroleukaemia
- Myeloid leukaemias
- Monocytic leukaemia
- Megakaryocytic leukaemia
What is it called when the leukaemia type arises in multipotent progenitor cells which have the ability differentiating into both myeloid & lymphoid?
Biphenotypic leukaemia
Is acute myeloid leukaemia more prevalent in the young or old population?
Old
List 6 options for the, largely unknown, aetiology of acute leukaemia?
- Chemicals
- Chemotherapy
- Radiotherapy
- Genetic: Downs Syn, Fanconi Syn
- Antecedent blood disorders (MDS, MPD)
- Viruses
List 8 features to look for in the history & examination to diagnose acute leukaemia?
- Rapid onset of symptoms
- Lethargy
- Infection
- Bleeding & bruising
- Bone pain
- Gum swelling
- Lymphadenopathy
- Skin rash
List the 4 features of a peripheral blood test in acute leukaemia?
- Anaemia
- Neutropenia
- Thrombocytopenia
- Blasts
What is the % presence of blast cells in the bone marrow for test in acute leukaemia diagnosis?
> 20%
What is so important about the M3 subtype of acute myeloid leukemia (M3 AML)?
Patients with APL can quickly develop life-threatening blood-clotting or bleeding problems if not treated
Describe the cytogenetics of M3 AML?
Translocation of chromosomes 15 & 17
Describe the cytogenetics of M2 AML?
Translocation of chromosomes 8 & 21
List the 6 different types of acute myeloid leukaemia’s (AML)?
- Secondary AML
- Relapsed AML
- MDS to AML
- Biphenotypic disease
- Elderly patients
- Refractory to induction
What are the 3 choices for managing AML?
- Intensive chemotherapy +/- stem cell transplant (pts <60-65, 5 yr survival approx 50%)
- Low Dose chemotherapy (pts>60-65, 5yr survival approx <10%)
- Supportive care (older pts, major co- morbidities, median survival 3-6 months)