Approach to anaemia 1 Flashcards
What is anaemia defined as?
Reduction of either:
- PCV or haematocrit
- RBC count
- Haemoglobin
Is anaemia associated with underlying disease?
Always - anaemia is a clinical sign, not a disease
Is acute or chronic anaemia worse?
Acute
Chronically anaemic animals can compensate
What are examples of responses to anaemia?
Increased RBC 2,3 DPG
Alterations in tissue perfusion
Alterations in behaviour
Different oxygen affinity behaviour (cats only)
What does 2,3 DPG do?
Lowers affinity of haemoglobin for oxygen
Facilitates release of oxygen
How does increased RBC 2,3 DPG help in response to anaemia?
Increased RBC 2,3 DPG causes lower O2-haemaglobin affinity
Better delivery of oxygen to tissues
What can only cats do in response to anaemia?
Different haemoglobins - respond over range of oxygena conditions
Tissue perfusion alters in response to anaemia. What hormonal effect does this have?
Lack of perfusion causes increased erythropoietin
Where is erythropoietin produced? What does it do?
Kidneys
Stimulates RBC production
Give an example of a behaviour associated with anaemia, particularly in cats
Pica
Give examples of what you may see on a physical exam of an anaemic animal
Jaundice Pallor Weakness Prolonged CRT Tachycardia etc
How can anaemia be classified (3 descriptions)
Degree of severity
Erythrocyte indexes
Regenerative response
What are the 3 degrees of severity for anaemia?
Mild, moderate, severe
What are examples of erythrocytes indexes when describing anaemia?
Microcytic, normocytic or microcytic
Hypochromic or normochroic
What are the 3 main causes of anaemia?
Inadequate production by bone marrow
Increased destruction of RBCs
Haemorrhage
What types of anaemia can be caused by inadequate production by bone marrow - severity, RBC index and regeneration?
Mild to severe
Normocytic, normochromic
Non-regenerative
What type of anaemia can be caused by increased destruction of RBCs - regeneration, RBC index and immune mediated?
Regenerative
Macrocytic hypo chromic or normocytic normochromic
Immune mediated or non-immune mediated
Does haemorrhage cause proportional or disproportional loss of blood components? Does it cause regenerative or non-regenerative anaemia?
Proportional
Regenerative usually
How does the body recover hypovolaemia after haemorrhage?
Interstitial fluid moves into vascular space (within a few hours)
A few hours after haemorrhage, how does the total protein differ? What other haematological abnormalities are present?
Low total protein - blood diluted by ISF
Decreased PCV, haematocrit and erythrocyte mass
How can acute blood loss present clinically?
Hypovolaemic shock - pallor, tachycardia, weak pulse, cold extremities, increased lactate
How long does blood need to be lost to define it as chronic?
More than 2 weeks
How long does chronic blood loss need to continue to develop iron deficiency anaemia in an adult?
1 month - abundant iron supply
Does acute or chronic blood loss cause IDA?
Chronic
Is chronic blood loss regenerative or non-regenerative?
Can be either
Eventually lack of iron slows down erythropoiesis