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Cardiovascular Block > L15 - Haemoglobinopathies and anaemia > Flashcards

L15 - Haemoglobinopathies and anaemia Flashcards

1
Q

Summarise erythrocyte lifecycle

A
  1. forms in red bone marrow
  2. circulates blood stream 120 days
  3. aged erythrocytes phagocytized in liver and spleen
  4. haem components of blood recycled
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2
Q

Describe how components of RBC are recycled?

A
  1. Haem components
    - heme –> biliverdin –> bilirubin
    - bilirubin then secreted from liver
    - iron transported in blood
  2. membrane proteins and globin proteins –> aa
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3
Q

Describe transport and storage of iron through body?

A
  • travels in blood bound to transferrin protein

- stored by protein ferritin in liver

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4
Q

Describe the cell lineage of an RBC?

A
  1. myeloid stem cell
  2. proerthroblast
  3. reticulocyte
  4. erythrocyte
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5
Q

Anaemia definition

give examples of how anaemia may arise

A

deficiency in number of erythrocytes or their haemoglobin content.

e. g. either losing them quickly (haemorrhage, haemolysis)
e. g. or not making them quick enough (Fe3+, folate, B12)

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6
Q

Symptoms of anaemia in patients

LOADS, sorry

A
  • yellowing of eyes (red in severe anaemia)
  • skin paleness, coldness, yellowing
  • SoB
  • muscular weakness
  • changed stool colour
  • fatigue, dizziness, fainting
  • low bp
  • palpitations, rapid hr, angina
  • spleen enlargement
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7
Q

Describe classification of anaemia (3)

A

by size of the erythrocytes.

  1. Microcytic
  2. normocytic
  3. macrocytic
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8
Q

Describe microcytic anaemia

  • cause
  • specific symptoms/signs
  • treatment
A

commonest, Fe3+ deficiency.

causes: menorrhagia, GI bleed, colorectal cancer in (>50)

SS: koilonychia (spooned nails)

Tx: ferrous sulphate

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9
Q

Normocytic anaemia

  • cause
  • management
A

commonest causes: active/post haemorrhage, RA, chronic disease, haemolytic anaemia

management:
transfusion for severe symptoms.

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10
Q

Reticulocyte count and what it indicates in anaemic patients

A
  1. High corrected reticulocyte count
    - appropriate response to anaemia from bone marrow
    - bone marrow releasing RBCs prematurely to cover for deficit
  2. Low corrected reticulocyte count
    - bone marrow not had time to respond (acute haemorrhage)
    - bone marrow failing to respond properly
    - problem with bone marrow
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11
Q

Macrocytic anaemia

  • causes
  • specific signs / symptoms
  • management
A

causes: B12 def, folate def, alcoholism

specific s&s: glossitis, paraesthesia, lemon tinge to skin, abnormal gait

tx: folate, b12 (hydroxycobalamin)

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12
Q

Pernicious anaemia

A
  • autoimmune disorder.
  • causes gastric mucosa atrophy.
    and destruction of parietal cells.
  • no hence intrinsic factor IF necessary for b12 absorption.
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13
Q

Sickle cell anaemia

  • genetic inheritance
  • results from
A
  • autosomal recessive.

- results from single glutamic acid to valine substitution at position 6 of beta globin polypeptide chain.

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14
Q

what causes the characteristic ‘sickle’ cell shape in sickle cell anaemia?

A
  • when HbS deoxygenated, molecules of Hb polymerise to form tactoids
  • tactoids will distort the RBC membrane
  • causes sickle shape
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15
Q

Describe the difference between homozygotes and heterozygotes with sickle cells?

A

Homozyogtes

  • can only produce HbS
  • all beta chains abnormal
  • sickle cell disease

Heterozygotes

  • mixture of HbA, HbS
  • asymptomatic trait
  • sickle cell trait
  • resistance to malaria
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16
Q

Crisis associated with sickle cell anaemia (3)

A
  1. Vaso-occulsive crisis
  2. aplastic crisis
  3. sequestration crisis
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17
Q

What is a vaso-occlusive crisis?

management

A
  • plugging of small vessels in bone
  • results in severe bone pain
  • causes systemic response (t.cardia, sweating, fever)

tx
- aggressive rehydration, o2, analgesia

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18
Q

Aplastic crisis

A
  • infection of adult sicklers with erythrovirus 19.
  • severe erythrocyte aplasia
  • low Hb, low reticulocyte count

(aplasia = failure of tissue to function properly)

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19
Q

Sequestration crisis

A
  • thrombosis of venous outflow
  • severe pain, loss of function
  • spleen common site
  • massive splenomegaly
20
Q

What is thalassemia ?

A
  • inherited
  • body makes abnormal form or inadequate amount of haemoglobin
  • large numbers of RBCs destroyed
21
Q

Definition of haemolysis

A
  • premature RBC destruction overloads pathways for haemoglobin breakdown
  • causing modest rise in unconjugated bilirubin
  • may cause jaundice
22
Q

describe what happens in intravascular haemolysis?

A
  • free haemoglobin released into plasma
  • free h.globin toxic, quickly bound to haptoglobin for transportation to liver
  • leads to fall in haptoglobin levels
23
Q

How may haemolysis lead to black urine (if sudden) ?

A

recap
- free h.globin toxic, bound to haptoglobin –> liver, [haptoglobin] falls

  • once haptoglobins saturated
  • albumin and haemopexin bind to h.globin for transport
  • if these become saturated
  • free haem may appear in urine, black appearance
24
Q

What is haemosiderinuria?

A
  • renal tubular cells can absorb Hb, degrade it, store it as haemosiderin
  • when these cells sloughed off –> haemosiderinuria
  • always indicative of intravascular haemolysis
25
Q

Describe extravascular RBC destruction?

where does it occur?

A

reticulo-endothelial cells of spleen and liver

26
Q

Describe key clinical features as a result of haemolysis

what increases, what decreases

A

Increase of

  • bilirubin
  • reticulocytes
  • lactate dehydrogenase (LDH)
  • urinary urobilinogen
  • urinary haemosiderin

decrease
- haptoglobin

jaundice

27
Q

Blood smear gives information on what

A

size, shape, colour of RBCs

should be done in addition of FBC

28
Q

State 2 cell membrane defects

A
  1. Hereditary spherocytosis

2. hereditary eliptocytosis

29
Q

What is Coombs test?

A
  • immunohaematological test to differentiate between immune and non immune causes of haemolytic anaemia
30
Q

State 2 red cell enzymopathies?

A
  1. Glucose-6-phosphate dehydrogenase deficiency (G6PD)

2. Pyruvate kinase deficiency

31
Q

What is aplastic anaemia?

A
  • total bone marrow failure
  • affects all cell lineage
  • infection , autoimmune
  • anaemia, leukopenia, thrombocytopaenia
32
Q

Describe myelodysplastic syndrome?

A
  • malignant infiltration of bone marrow by immature blood cells
  • anaemia, leukopenia, thrombocytopenia, splenomegaly
33
Q

Describe polycythaemia?

true vs relative polycythaemia

A

Hb greater than upper limit:

  1. increase in erythrocyte number –> true polycythaemia
  2. reduction in plasma volume –> relative polycytheaemia
34
Q

Describe difference between primary and secondary polycythaemia?

A

Primary
- due to inappropriate over-production of RBCs

Secondary
- increase in erythropoietin production

35
Q

what factors may cause an increase in erythrocyte production?

biological, environmental, social

A
  • smoking
  • high altitude
  • renal hypoxaemia
36
Q

where are leukocytes produced and mature?

any exceptions?

A
  • produce, mature in bone marrow

- only exception: T lymphocytes which mature in thymus

37
Q

All white cells are formed from what cell …

A

multipotent haematopoietic stem cell

38
Q

Multipotent haematopoietic stem cells form what?

give examples

A

EITHER
1. myelocytes (form granulocytes, basophils, eosinophils and neutrophils )

  1. lymphocytes (form B and T lymphocytes)
39
Q

Leukaemia

A

malignancy of bone marrow stem cells.

may arise from either lymphoid or myeloid stem cells.

40
Q

symptoms of leukaemia

A

symptoms arise from affected stem cell hindering function of other stem cells in bone.

  • -> anaemia
  • -> thrombocytopaenia

symptoms

  • lethargy
  • easy bruising
  • epistaxis (nose bleed)
  • recurrent infections
41
Q

definition of lymphoma

A

malignancy specifically lymphocytes, includes lymph nodes.

42
Q

Describe two histological divisions of lymphoma

A
  1. Hodgkin’s (rare)
  2. non-hodgkins (10x common)

depends on the cell involved… presence of abnormal Reed-Sternberg cells gives diagnosis of Hodgkin’s

43
Q

Describe multiple myeloma

A
  • malignancy of plasma cells characterised by increased monoclonal antibodies.
  • median survival 3 years
44
Q

Describe some signs of multiple myeloma and how they come about?

briefly describe the pathophysiology

A
  1. Bence-Jones protein
  2. Pepper-pot skull

pathophys

  • increase in antibody, igG or igA
  • will release IL-1
  • IL-1 overexpresses RANKL
  • stimulates osteoclasts
  • bone pain
  • hypercalcaemia
  • multiple osteolytic skull lesions
  • overactivity suppresses haematopoeitic stem cells causing normocytic anaemia.
45
Q

management of multiple myeloma

A
  • radiotherapy

- bisphosphonates

46
Q

Thrombocytosis

A

body makes too many platelets.

47
Q

thrombocytopaenia

A

body makes too few platelets.

Cardiovascular Block (16 decks)

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