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Haemotology > When haematopoiesis goes wrong > Flashcards

When haematopoiesis goes wrong Flashcards

1
Q

Overproduction of cells

A

Either caused by a physiological reaction due to stimulus or due to myeloproliferative disorders (neoplasm)

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2
Q

Myeloproliferative Neoplasm

A
  1. Essential thrombocythemia
  2. Polycythaemia vera
  3. Myelofibrosis
  4. Chronic myeloid leukaemia

*All of these disorders involve dysregulation at the multipotent haematopoietic stem cells*

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3
Q

Myeloproliferative disorders- clinical features

A
  • Overproduction of one or several blood elements with dominance of a transformed clone
  • Hypercellular marrow (marrow fibrosis)
  • Cytogenetic abnormalities
  • Thrombotic/ haemorrhagic diatheses
  • Extramedullary hemopoiesis (liver/spleen)
  • Potential to transform to acute leukaemia
  • Overlapping clinical features
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4
Q

Many patients have a specific point mutation in one copy of the Janus kinase 2 gene (JAK2)

A
  • A cytoplasmic tyrosine kinase on chromosome 9à increased proliferation and survival of haematopoietic precursors
  • We now have specific drugs targeting the aberrant protein
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5
Q

1. Essential thrombocythemia- “too many platelets”

A

A rare chronic blood cancer (myeloproliferative neoplasm) characterised by the overproduction of platelets (thrombocytes) by megakaryocytes in the bone marrow. Can develop into acute myeloid leukaemia or myelofibrosis.

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6
Q

Essential thrombocythemia characterised by

A
  • Excess platelets in blood
  • Large and excess megakaryocytes in bone marrow
  • thombotic events- blood clot in vein or artery
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7
Q

essential thrombocythemia- make sure you consider

A

Make sure high platelet count is persistent rather than transient (infection, inflammation eg. Rh arthritis, other tissue injury, haemorrhage, cancer, redistribution of platelets (post splenectomy and hyposplenism)

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8
Q

managment of essential thrombocythemia

A
  • Any cardiovascular risk factors should be aggressively managed
  • Aspirin
  • screen fro Jak2 and CALR mutation
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9
Q

essential thrombocythaemia: high risk patients

A
  • >60 year
  • Platelet count >1500 or disease- related thrombosis/haemorrhage
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10
Q

essential throm bocythemia drug

A
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11
Q

2. Polycythaemia vera (PV)

A

High red blood cells

  • Diagnostic criteria= high haematocrit or raised red cell mass
  • JAK2 mutation present in 95% of PRV patients
  • No reactive cause found
  • Some patients also have high platelets and neutrophils
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12
Q

characteristic sof polycythameia vera patient

A
  • Median age 60
  • Male= female
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13
Q

Clinical features of polycythamia vera

A
  • Significant cause of arterial thrombosis
  • Venous thrombosis
  • Haemorrhage into skin or GI tract
  • Pruritis- itchiness
  • Splenic discomfort, splenomegaly
  • Gout- due to excess cell breakdown
  • In some transformation to myelofibrosis or acute leukaemia
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14
Q

increase in RBC can be

A

relative or absolute

  • Relative= normal red cell mass with less plasma volume or
    • Make sure patient isn’t dehydrated
  • Absolute= increase red cell mass
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15
Q

two types of absolute polycythaemia

A

Primary- abnormality originates in bone marrow

  • Polycythaemia vera only example

Secondary- caused by increased levels of EPO Physiologically response to hypoxia

  • Physiological response to hypoxia e.g. high altitude, chronic lung disease
  • Abnormal production e.g.:
    • Renal carcinoma
    • Renal artery stenosis
    • Uterine tumours
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16
Q

polycythaemia summarised

A
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17
Q

Management of Polycythaemia vera (PV)

A
  • Venesection to maintain Hct to <0.45
  • Aspirin 75mg unless contraindicated
  • Manage CVS risk factors e.g. cholesterol and BP
  • Sometimes drug to reduce the overproduction of cells should be considered
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18
Q

3. Myelofibrosis

A

Myelofibrosis is an uncommon type of bone marrow cancer that disrupts your body’s normal production of blood cells. Myelofibrosis causes extensive scarring in your bone marrow, leading to severe anaemia that can cause weakness and fatigue.

19
Q

what does myekofibrosis cause

A

heabiltiy fibrotic marrow–> little space of haemopoieisi

  • need for extramedullary haematopoiesis–> cause of massive splenomegaly
20
Q

blood film of someone with myelofibrosis

A

Blood vessels get squeezed out of the bone due to reduced space—blood film shows red cells looking like tear drops

21
Q

myelofibrossi may be an end result of

A
  • may be end result of Polycythaemia vera or Essential thrombocythemia
22
Q

primary disease of myelofibrosis

A

PMF

  • starts with proliferative phase when all counts may be high, then in all cases progressive pancytopenia (all blood cells low) due to marrow fibrosis and hyperspenism
23
Q

clinical feauture of myelofibrosis

A
  • Constitutional symptoms:
    • Fatigue
    • Sweats
  • Consequence of splenomegaly
    • Pain
    • Early satiety
    • Splenic infarction
24
Q

treatment of myelofibrosis

A
  • Bone marrow failure requiring transfusions of blood products
25
Q

myelofibrosis results in

A
  • Transformation to leukaemia
  • Early death
26
Q

4. CML (Chronic myeloid leukaemia)

A
  • Usually presents with very high WCC
  • Patients may present with symptomatic splenomegaly, hyperviscosity (sticky blood) or bone pain
  • Disease of adults, very rare in children
27
Q

CML blood film

A

Blood film and marrow show excess of myeloid series from blast through

28
Q

Symptoms of CML

A

due to hyperviscous blood

  • Headache
  • Blurred vision
  • Lung problems
  • Kidney failure
29
Q

causes of CML

A
  • Reciprocal switch of genetic material between chr 9 and 22
  • Switches on receptor tyrosine kinase
30
Q

treatment for CML

A

tyrosine kinase inhibitors

31
Q

Pancytopenia

A

Reduction in white cells, red cells and platelets

32
Q

Why may someone become pancytopenia

A
  1. Reduced production (most common)
  2. Increase removal
    • Splenic pooling
    • Hypersplenism in massive splenomegaly
    • Immune destruction
    • Hamophagocytosis- chewing up of the cells in the bone marrow v v rare
33
Q
A
34
Q

What can cause reduced production: pancytopenia

A
  • B12/folate deficiency
  • Bone marrow infiltration by malignancy (blood cancers of other cancers)
  • Marrow fibrosis
  • Radiation
  • Drugs – chemotherapy, antibiotics, anticonvulsants, psychotropic drugs, DMARDs
  • Viruses – EBV, viral hepatitis ,HIV, CMV
  • Idiopathic aplastic anaemia
  • Congenital bone marrow failure eg Fanconi’s anaemia, dyskeratosis congenital – present in childhood
35
Q

Aplastic anaemia

A
  • Pancytopenia with a hypocellular bone marrow in the absence of an abnormal infiltrate with no increase in reticulin (fibrosis)
  • Mortality is high as cure is difficult – immune treatments and bone marrow transplantation
  • Deaths often due to neutropenic infection or bleeding
36
Q

platelets play a kery roel in. haemostasis to facilitate clot formation- platelet plug

A
  • Adhesion to damaged endothelium
  • Activation- change in shape from disc and release of granules
  • Aggregation – clumping together of more platelets to form the plug
37
Q

platelet Disorders

A
  • Quantitative- low (thrombocytopenia)
  • Qualitative- often normal number but defective function
38
Q

Thrombocytopenia

  • Acquired (common)
A
  • Decreased platelet production
    • B12 of folate deficiency
    • Acute leukaemia or aplastic anaemia
    • Liver failure
    • Sepsis
    • Cytotoxic chemotherapy
  • Increased platelet consumption
    • Massiv haemorrhage
    • Disseminated intravascular coagulation
    • Thrombotic thrombocytopenic purpura
  • Increased platelet destruction
    • Autoimmune thrombocytopenic purpura
    • Drug induced e.g. heparin
    • Hyperspenism resulting in increased destruction and splenic pooling of platelets
39
Q

hereditary disroders of paltelet function

A

e.g. Bernard Soulier syndrome, Glanzmans thrombasthenia

40
Q

acuiqred disorderr of platelet function

A
  • Aspirin/nsaids
  • Uraemia
  • Hypergammaglobulinemia e.g. myeloma
  • Myeloproliferative disorders
41
Q

Consequences of severe thrombocytopenia

*

A
  • Patients generally not symptomatic until the platelet count < 30
  • Easy bruising
  • Petechiae, purpura (blood spots or skin hemorrhages)
  • Mucosal bleeding
  • Severe bleeding after trauma
  • Intracranial haemorrhage
42
Q

Immune thrombocytopenic purpura

A

most common cause- autoantibodies against glycoprotein (GP) IIb/ IIIa and GPIb/IX

  • Can be secondary to autoimmune disease e.g SLE and lymphoproliferative disorders e.g. lymphoma CLL
  • Treated with immunosuppression (corticosteorids or IV immunoglobulin first line)
  • Platelet transfusions do not work – transfuse platelets get destroyed too
43
Q
A

Haemotology (12 decks)

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