Lecture 2 - Regenerative anaemia Flashcards

1
Q

what is anaemia?

A

decrease in RBC mass

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2
Q

what is haemolysis?

A

destruction of RBC

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3
Q

what is haemoglobinemia?

A

free haemoglobin in plasma

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4
Q

what is bilrubinaemia?

A

increase in serum bilirubin

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5
Q

what is bilirubinuria?

A

bilirubin excretion in urine

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6
Q

what is ERYTHROPOIESIS

A

formation and maturation of RBC

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7
Q

what is the main stimulus for erythropoiesis

A

hypoxia

EPO

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8
Q

what is EPO?

A

erythropoietin - principle growth factor promoting proliferation and differentiation

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9
Q

sources of EPO?

A
adult = kidney
foetus = liver
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10
Q

where does EPO act in the RBC life cycle?

A

at every stage

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11
Q

what is the life cycle of the RBC?

A

rubriblast –> pro-rubricyte –> rubricyte –> metarubricyte – polychromataphil –> mature RBC

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12
Q

what is the last stage able to mitotically divide? still with a nucleus?

A

rubriblast: earliest form, last stage for mitotic division
metarubricyte: last nucleated form

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13
Q

what are some clinical signs of anaemia?

A

weaknesses - lethargy and decreased oxygen
pale mucuous memo
tachycardia - compensatory response
tachypnoea - ^^
in severe cases - cold extremities (decreased blood vol)
weak peripheral pulse
heart murmur - blood viscosity changes

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14
Q

what are the two causes of anaemia

A
  1. RBC loss –> region response to haemorrhage or haemolysis

2. decreased RBC production –> non-regen

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15
Q

what are the three ways (in order from best to worst) to assess regeneration?

A

best = reticulocytosis - most accurate assessment
second best = blood smear - polychromasia
third best = macrocytosis and hypochromasia

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16
Q

how do you assess anaemia in horses?

A

serial monitoring of PCV/CBC to assess improvement

–> do not release polychromatophils into blood stream

17
Q

what are some morphological changes on blood smears?

A

polychromasia
macrocytosis –> often only indicator in horse
anisocytosis = variable cell size, hypochromasia
increase howell-jolly bodies - nuclear remnants
increase nRBCs - nucleated RBC
basophilic stippling

18
Q

what are the two forms of reticulocyte

A
  1. aggregate - polychromataphils, released in low numbers dogs 1%, 0.4% in cats
    analyser only counts these
  2. punctuate - only in cat, more mature, only with few fine reticulin granules –> long maturation time in cats, >2 weeks
19
Q

w/ regenerative anaemia the absolute reticulocyte count is above reference interval - what are the reference ranges of dogs and cats?

A

dog - 120x10^L

cat - 60x10^9L –> approx half in health

20
Q

what is MCV

A

mean corpuscular volume

average RBC size, if increased then immature cells

21
Q

what is MCHC

A

meach corpuscular haemoglobin concentration

Hb per average RBC, if MCHC decreased, immature cell = more diluted

22
Q

what is RDW

A

red cell distribution width

23
Q

what is the 4 stages of acute haemorrhage

A
  1. per acute - no change Hct or protein
    - whole volume loss from circ. no time to vol replace
  2. acute stage I (within hrs)
    - decrease HCt and protein, fluid shift extravasc to intravasc space, activation of RAAS, pre-rege
  3. acute stage II - 3 - 5 DAYS
    - EPO produced - marrow stim evident in blood; Hct and protein increase.
24
Q

what is the equine response to haemorrhage

A

appear non-regenerative, do not release polychromatophils/reticulocytes. do not release many nRBC
may have macrocytosis

25
Q

what are the two types of haemolysis?

A

intravascular: rupture of the RBC within the vessel –> ghost cells will be evident
extravascular: phagocytosis of RBC by MO in spleen, bone marrow, liver
- -> sperhocyte present

26
Q

what are the key findings of haemolysis

A

hyperbilirubinaemia
bilirubinuria
normal protein

27
Q

what are the star responses to haemolysis

A

stage 1: within hrs = decrease Hct with normal protein, no evident of regeneration +/- haemolysed plasma and haemoglobinruia.
stage II within 3-5 days = EPO produced, region evidence in blood. often see hyperbilirubinemia/jaundice

28
Q

what are some intravascular causes of haemolysis?

A
immune mediated disease - IMHA
oxidative injury - paracetamol in cats, onions in dogs
infections
toxicosis - zinc, copper
genetic disease
29
Q

what are some extravascular causes of haemolysis?

A
immune mediated disease - IMHA
oxidative injury - paracetamol in cats, onions in dogs
infections
toxicosis - zinc, copper
genetic disease
PLUSSS ---- 
neoplasma
fragmentation (DIC)
30
Q

what are some diagnostic indicators of IMHA?

A
  • spherocytes
  • auto-agglutination and in saline positive agglutination
  • coombs test