Anaemia aetiology + pathogenesis Flashcards
What is anaemia
a decreased haematocrit, packed cell volume or haemoglobin
what is haematocrit
(MCV x RBC) +10wh
at does PCV tell us
percentage of packed red cells in blood volume
List 4 clinical signs associated with anaemia
Inadequate perfusion/ oxygenation - pale mm, lethargy, exercise intolerance
compensatory mechanisms- tachypnoea, tachycardia
other signs- poor pulse quality, haemic murmur
signs related to underlying pathology- splenomegaly, lymphadenopathy, pain, pica, icterus, melana
How can anaesthesia affect PCV
the spleen relaxes up to 30% of circulating RBCs can enter when this happens
Does severity of the anaemia relate to clinical condition?
Not necessarily, chronic animals with an extremely low PCV can show fewer clinical signs than acute animals.
Canine PCV is 30-40 how would you grade the anaemia
mild
Canine PCV is 20-30 how would you grade the anaemia?
moderate
Canine PCV is <20 how would you grade the anaemia?
severe
Feline PCV is 25-30 how would you grade the anaemia?
mild
Feline PCV is 15-25 how would you grade the anaemia?
moderate
Feline PCV is <15 how would you grade the anaemia?
severe
What RBC indices are used to grade anaemia?
MCV and MCHC
What does high MCV likely indicate in anaemic patients?
Regenerative (larger cells in circulation = reticulocytes)
Why does MCHC drop?
Larger cells in regenerative anaemia means the same volume in a larger cell,
Reduced volume in normal size cells.
What happens to MCV and MCHC when reticulocytes are in circulation?
MCV increases due to larger cells,
MCHC decreases due to same volume in these larger cells.
Why is anisocytosis seen in regenerative anaemia?
Reticulocytes are larger than mature RBCs
List 4 non-specific indicators seen in regenerative anaemia
Nucleated RBCs
Basophilic stippling
Howell-Jolly bodies
Heinz bodies
List the 2 most common causes of regenerative anaemia
Haemorrhage
Haemolysis
List 3 common causes of non-regenerative anaemia
Decreased bone marrow production of RBCs,
Pre-regenerative anaemia (bone marrow can take 3-5 days to respond to anaemia),
Chronic haemorrhage or haemolysis
What do spherocytes indicate
immune mediated haemolysis
what do schistocytes indicate
intravascular red cell injury- mechanical injury
what do keratocytes indicate
intravascular red cell injury
what do Heinz bodies indicate
Heinz body haemolysis
oxidative damage
what do dacryocytes indicate
iron deficiency
myelofibrosis
what is it called when IMTP is seen alongside IMHA
Evans syndrome
what does hypochromic, microcytic RBCs indicate
iron deficiency anaemia
what are the 3 main causes of anaemia
blood loss
haemolysis
suppression of erythropoiesis
Schistocytes and acanthocytes on blood smear can indicate what neoplasm?
splenic haemangiosarcoma
List 3 common signs of mild/ chronic bleeding
melena
chronic/ multiple small wounds
GI or blood borne parasitism
What can be used to immediately treat anaemia caused by intra-cavitary bleeding (short term)
autotransfusion
List 3 things that can cause IMHA
reaction to normal self antigen,
Reaction to infectious agents bound to cell surface,
Reaction to non-biologic antigen bound to cell surface.
List 3 things that can cause a body to react to its own self antigens on RBCs
Primary immune system dysfunction and loss of tolerance,
Antigen exposed due to cell damage,
Similarity between self antigen and foreign antigen.
Non regenerative anaemia can be…
Intra-marrow
or
extra-marrow
List 4 causes of intra-marrow non-regenerative anaemia
infection
chronic damage
neoplasia
law of raw materials (iron deficiency)
List 3 causes of extra-marrow non-regenerative anaemia
CKD
excessive oestrogen
FeLV
what is the most common cause of iron deficiency
chronic haemorrhage
Most common cause of non-regenerative anaemia seen in SA clinical practice?
Anaemia of inflammation/chronic disease
