Week 19 - Polycythemia, Vit B12/Folate deficiency, thalessaemia Flashcards

1
Q

what is Polycythaemia vera

A

a raised RBC count, haemoglobin and packed cell volume/haematocrit

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2
Q

what warrants investigation into Polycythaemia

A

If packed cell volume/haematocrit persistently raised (male >0.52, female >0.48) this warrants investigation

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3
Q

what is the mutation in Polycythaemia and what is the percentage

A

90% have JAK2 mutation

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4
Q

what is the presentation of Polycythaemia

A

headaches, dizziness, lethargy, sweating and pruritus

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5
Q

what is there increased risk of in Polycythaemia

A

thrombosis - especially strokes, and bleeding - hyperviscosity and platelet dysfunction

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6
Q

what may increased cell turnover in Polycythaemia lead to

A

gout

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7
Q

what are the clinical signs seen in Polycythaemia

A

plethora,rosacea, palpable splenomegaly

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8
Q

what are the investigations carried out for Polycythaemia

A

Investigations: elevated WCC, elevated platelets, iron deficiency, EPO estimation normal or low

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9
Q

what is seen in the bone marrow in polycythemia

A

hypercellularity

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10
Q

what is the management of Polycythaemia Vera

A

Management: aspirin (75mg/day), venesection (haematocrit to <0.45)

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11
Q

what is given in advanced cases of polycythaemia vera

A

Advanced disease: hydroxycarbamide to suppress erythropoiesis

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12
Q

what is the median survival in polycythemia vera

A

Median survival >10 years, 10% transform to myelofibrosis, 5% to AML

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13
Q

polycythaemia vera is the proliferation of what cells

A

eryhtroid cells

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14
Q

what is found in the blood with polycythemia vera

A

high haemoglobin

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15
Q

what JAK2 inhibitors are used in treatment

A

The mutation to remember is JAK2. Treatment might involve JAK2 inhibitors, such as ruxolitinib

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16
Q

what does Myelofibrosis
result from

A

primary Myelofibrosis, polycythaemia vera or essential thrombocythaemia

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17
Q

what is Myelofibrosis

A

where the proliferation of a single cell line leads to bone marrow fibrosis, where bone marrow is replaced by scar tissue.

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18
Q

bone marrow is replaced by scar tissue in response to what in Myelofibrosis

A

in response to cytokines released from the proliferating cells

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19
Q

what is one particular cytokine concerned with Myelofibrosis

A

fibroblast growth factor

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20
Q

what does fibrosis in Myelofibrosis affect

A

the production of blood cells and can lead to low haemoglobin (anaemia), low white blood cells (leukopenia) and low platelets (thrombocytopenia)

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21
Q

what happens when the bone marrow is replaced with scar tissue

A

the production of blood cells haematopoiesis starts to happen in other areas known as extramedullary haemotopoiesis

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22
Q

what does production of blood cells in the liver and spleen cause

A

hepatomegaly, splenomegaly, and portal hypertension

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23
Q

what happens when extramedullary haematopoeisis happens around the spine

A

it can cause spinal cord compression

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24
Q

what will a blood film in myelofibrosis show

A

Teardrop-shaped red blood cells

Anisocytosis (varying sizes of red blood cells)

Blasts (immature red and white cells)

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25
Q

what is the initial presentation of myeloproliferative disorders

A

initially may be asymptomatic

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26
Q

what are the non specific symptoms that myeloproliferative disorders can present with

A

Fatigue
Weight loss
Night sweats
Fever

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27
Q

what is the major complication of polycythaemia

A

gout

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28
Q

what is the most common complication of polycythaemia and thrombocythaemia

A

Thrombosis is a common complication of polycythaemia and thrombocythaemia, leading to myocardial infarction, stroke or venous thromboembolism (e.g., DVT and PE).

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29
Q

what are the clinical signs of polycythaemia

A

Ruddy complexion (red face)
Conjunctival plethora (the opposite of conjunctival pallor)
Splenomegaly
Hypertension

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30
Q

what is required to confirm the diagnosis of myelofibrosis

A

bone marrow biopsy is required to confirm the diagnosis

bone marrow aspiration may be dry with myelofibrosis, as the bone marrow has turned into scar tissue

31
Q

testing for what genes can help with the diagnosis and management of myelofibrosis

A

Testing for the JAK2, MPL and CALR genes can help with diagnosis and management.

32
Q

what is the management of primary myelofibrosis

A

No active treatment for mild disease with minimal symptoms
Supportive management of complications, such as anaemia, splenomegaly and portal hypertension
Chemotherapy (e.g., hydroxycarbamide) to help control the disease
Targeted therapies, such as JAK2 inhibitors (ruxolitinib)
Allogeneic stem cell transplantation (risky but potentially curative)

33
Q

what is the management of polycythaemia vera

A

Venesection to keep the haemoglobin in the normal range

Aspirin to reduce the risk of thrombus formation

Chemotherapy (typically hydroxycarbamide) to help control the disease

34
Q

what is the management of essential thrombocythaemia

A

Aspirin to reduce the risk of thrombus formation

Chemotherapy (typically hydroxycarbamide) to help control the disease

Anagrelide is a specialist platelet-lowering agent

35
Q

what kind of anaemia does vitamin B12 deficiency cause

A

macrocytic anaemia

36
Q

what are the key causes of a low B12

A

Pernicious anaemia

Insufficient dietary B12 (particularly a vegan diet, as
B12 is mostly found in animal products)

Medications that reduce B12 absorption (e.g., proton pump inhibitors and metformin)

37
Q

what is pernicious anaemia

A

an autoimmune condition involving antibodies against the parietal cells or intrinsic factor

38
Q

what is the pathophysiology of pernicious anaemia

A

the parietal cells of the stomach produce a protein called intrinsic factor

intrinsic factor is essential for the absorption of vitamin B12, in the distal ileum

39
Q

in pernicious anaemia, autoantibodies target what?

A

either the partietal cells or intrinsic factor, resulting in a lack of intrinsic factor and a lack of absorption iof btamin B12

40
Q

what are the neurological symptoms that vitamin B12 deficiency can cause

A

Peripheral neuropathy, with numbness or paraesthesia (pins and needles)
Loss of vibration sense
Loss of proprioception
Visual changes
Mood and cognitive changes

41
Q

what are the autoantibodies for pernicious anaemia

A

Intrinsic factor antibodies (the first-line investigation)

Gastric parietal cell antibodies (less helpful)

42
Q

what is initially given to patients with B12 deficiency depending on symptoms

A

Intramuscular hydroxocobalamin

43
Q

if patient has no neurological symptoms, how long is Intramuscular hydroxocobalamin given for

A

3 times weekly for two weeks

44
Q

if the patient has neurological symptoms, how often is Intramuscular hydroxocobalamin given

A

alternate days until there is no further improvement in symptoms

45
Q

what does maintenence treatment depend on

A

the cauase

46
Q

what is the maintence for penicious anaemia

A

2-3 monthly injections of Intramuscular hydroxocobalamin for month

47
Q

what is the maintenance for diet related

A

Diet-related – oral cyanocobalamin or twice-yearly injections

48
Q

what is essential to do if there is B12 and folate deficiency together

A

it is essential to treat the B12 deficiency first before correcting the folate deficinecy.

49
Q

what happens if you give patients folic acid when they have a B12 deficiency

A

lead to subacute combined degeneration of the cord, with demyelination in the spinal cord and severe neurological problems.

50
Q

what is thalassaemia caused by

A

a genetic defect in the protein chains, that make up haemoglobin

51
Q

what does normal haemoglobin consist of

A

two alpha-globin and two beta-globin chains

52
Q

what do defects in alpha-globin chains lead to

A

alpha thalassaemia

53
Q

what do defects in the beta-globin chains lead to

A

beta thalassaemia

54
Q

both alpha and beta thalassamia are what?

A

autosomal recessive

55
Q

what is the overall effect of thalassaemia

A

varying degrees of anaemia, depending on the type and mutation

56
Q

what happens in thalassaemia to the RBCs

A

they are more fragile and break down easily causing haemolytic anaemia

57
Q

what does the spleen act as in thalassaemia

A

the spleen acts as a sieve, filtering the blood and removing older cells. the spleen collects all the destroyed RBCs resulting in splenomegaly

58
Q

what are the features of thalassaemia

A

Microcytic anaemia (low mean corpuscular volume)
Fatigue
Pallor
Jaundice
Gallstones
Splenomegaly
Poor growth and development

59
Q

what is used to diagnose globin abnormalities

A

haemoglobin electrophoresis

60
Q

why may iron overload occur in thalassaemia

A

Increased iron absorption in the gastrointestinal tract

Blood transfusions

61
Q

Iron overload in thalassaemia can cause symptoms and complications of what?

A

Liver cirrhosis
Hypogonadism
Hypothyroidism
Heart failure
Diabetes
Osteoporosis

62
Q

what does management of thalassaemia alpha involve

A

Monitoring
Blood transfusions
Splenectomy may be performed
Bone marrow transplant can be curative

63
Q

what do the gene defects in beta thalassaemia consist of

A

either abnormal copies that retain some function or deletion genes with no function in the beta-globin.

64
Q

what are the three types of beta-thalassaemia

A

Thalassaemia minor
Thalassaemia intermedia
Thalassaemia major

65
Q

patients with thalassaemia minor have what?

A

carriers of abnormally funcitoning beta-globin gene

they have one abnormal and one normal gene

66
Q

what does thalassaaemia minor cause

A

mild microcytic anaemia and usually only requires monitoring

67
Q

what do patients with beta thalassaemia intermedia have

A

two abnormal copies of the beta-globin gene

68
Q

what does thalassaemia intermedia cause

A

more signifianct microcytic anaemia.

patients require monitoring and may need occasional blood transfusions

69
Q

what is given to prevent iron overload

A

They may require iron chelation to prevent iron overload.

70
Q

what are patients with beta thalassaemia major

A

are homozygous for the deletion genes.

they have no functioning beta globin genes

71
Q

what are the abnormal features relating to bone changes include

A

Frontal bossing (prominent forehead)
Enlarged maxilla (prominent cheekbones)
Depressed nasal bridge (flat nose)
Protruding upper teeth

72
Q

what does management of thalassaemia major involve

A

regular transfusions, uron chelation and splenectomy

a bone marrow transplant can be curative

73
Q
A