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Haematology > Anaemia and microcytic anaemias > Flashcards

Anaemia and microcytic anaemias Flashcards

1
Q

what is anaemia

A

reduced total red cell mass

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1
Q

steady state anaemia adult male

A

Hb <130g/L
Hct <0.38

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2
Q

steady state anaemia adult female
(Hb and Hct)

A

Hb <120g/L
Hct <0.37

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3
Q

normal Hb male

A

130-180g/L

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4
Q

normal Hb female

A

120-160g/L

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5
Q

how can we measure Hb concentration
(4 step process)

A
  1. Burst the red cells to create Hb solution
  2. Stabilise the Hb molecules
  3. Measure the optical density at 540nm
  4. then basically measure the redness
    the redder it is the more Hb
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6
Q

how do we measure Haematocrit

A

Ratio (or commonly expressed as the percentage) of the whole blood that is red cells if the sample was left to settle
Modern machines calculate this by adding up the volume of the red cells it counts (if we know the number and size of cells it can work it out)

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7
Q

when are Hb or Hct NOT good markers of anaemia?

A
  1. acute trauma
  2. patient has been given lots of fluids - Hb can be falsely low
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8
Q

are reticulocytes smaller or larger than average red cells?

A

larger

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9
Q

why do reticulocytes stain purple and not red?

A

still have some RNA which stains blue

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10
Q

what does the MCV tell us

A

average size of the red cells

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11
Q

pathophysiological classification of anaemia

A

decreased production (low reticulocyte count)

increased destruction (high reticulocyte count)

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12
Q

anaemia - decreased production types

A
  • hypoproliferative anaemia
  • maturation defect (failure to produce Hb or failure of cell division)
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13
Q

anaemia - increased destruction types

A
  • blood loss
  • haemolysis (premature red cell destruction)
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14
Q

in increased destruction anaemia will the reticulocyte count be high or low

A

high because trying to replace

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15
Q

MCV low - what type of anaemia

A

microcytic

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16
Q

MCV high - what type of anaemia?

A

macrocytic

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17
Q

If MCV low (microcytic) consider problems with __________

A

haemoglobinisation

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18
Q

If MCV high (macrocytic) consider problems with __________

A

cell division ie maturation

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19
Q

does haemoglobin synthesis occur in the nucleus or the cytoplasm of red cell precursors?

A

cytoplasm

20
Q

what do you need to make Hb

A

Available iron, porphyrin ring, globins (alpha and beta)

21
Q

microcytic anaemia - what’s going on

A

missing one of the elements needed to make haemoglobin: Available iron, porphyrin ring, globins (alpha and beta)

nucleus machinery is intact so cells keep dividing
One of the signals to stop dividing is Hb accumulation
This is delayed
As a result more cell divisions occur and the cells are smaller (microcytic)‏

  • too many divisions, progeny get smaller, not as much Hb in them
22
Q

is microcytic anaemia a problem with the nucleus or cytoplasm?

A

cytoplasm

23
Q

commonest cause of microcytic anaemia

A

iron deficiency

24
Q

causes of hypochromic microcytic anaemias

A

haem deficiency
- lack of iron for erythropoiesis
- problems with porphyrin synthesis

globin deficiency
- Thalassaemia (trait, intermedia, major)

25
Q

iron is potentially toxic, true or false

A

true - so always chaperoned! always stuck to another protein in the body - transferrin or ferritin

26
Q

where is the majority of our iron

A

in our blood cells

27
Q

how much iron do we lose a day

A

1mg/day (small amount) just from skin shedding and stuff idk

28
Q

what is iron bound to in the transport system

A

transferrin

29
Q

iron is stored in ______ mainly in the _______

A

ferritin
liver

30
Q

what is used to assess storage iron status

A

serum ferritin

31
Q

how many binding sites for iron does transferrin have

A

2

32
Q

what is transferrin role in transporting iron

A

Transports iron from donor tissues (macrophages, intestinal cells and hepatocytes) to tissues expressing transferrin receptors (especially erythroid marrow)

33
Q

what is ferritin

A

large intracellular protein
can store loadsss of iron

34
Q

what does low ferritin mean

A

iron deficiency (because we don’t make lots of ferritin if we don’t have lots of iron to store)

35
Q

iron deficiency can be confirmed by a combination of _________ (decreased functional iron) and reduced _______ _____ (low serum ferritin)

A

anaemia

storage iron

36
Q

Sequential consequences of negative iron balance

A
  1. Exhaustion of iron stores (ferritin falls)
  2. Iron deficient erythropoiesis then starts (MCV starts to fall)
  3. Anaemia then develops
  4. Epithelial changes (late effects in other sites of the chronic lack of iron)
    -skin
    -koilonychia
    -angular chelitis
37
Q

causes of iron deficiency
(3 points)

A
  • insufficient dietary iron (rare)
  • losing iron - usually blood loss (GI, menstrual, urinary)
  • malabsorption e.g. coeliac
38
Q

where is iron absorbed

A

proximal small bowel

39
Q

causes of chronic blood loss

A

Menorrhagia

Gastrointestinal
-Tumours
-Ulcers
-Non-steroidal anti-inflammatory agents

Haematuria

40
Q

A small volume gastrointestinal blood loss can occur without any symptoms or signs of bleeding. 5mls of blood a day would be ____mg iron and might go unnoticed

A

2.5

41
Q

oral iron side effects

A

Mainly GI and related to elemental iron load on the gut
Constipation, nausea, vomiting, abdo pains, dark stools
This can result in poor compliance

42
Q

oral iron side effects are dose dependent, true or false

A

true - more you give, more side effects

43
Q

daily dose of iron that is sufficient for anaemia

A

65mg

44
Q

what is sodium feredetate (sytron)

A

liquid prep of iron, used in paediatrics

45
Q

when would parenteral (IV) iron be used instead of oral?

A

Poor tolerance of oral iron
Poor compliance with oral iron
Malabsorption issues (rare)
Specific situations (eg renal anaemia)

46
Q

when giving iron for anaemia, how long after starting treatment do we assess response?

A

4-6 weeks (FBC)

47
Q

iron treatment for anaemia - typically need to continue for how long to replenish?

A

couple of months when you’re back to normal

48
Q

Sequential consequences of negative iron balance

A
  1. Exhaustion of iron stores (ferritin falls)
  2. Iron deficient erythropoiesis (MCV falls)
  3. Microcytic anaemia develops
  4. Epithelial changes (effects elsewhere) - skin, koilonychia, angular chelitis

Haematology (36 decks)

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