Feline Anaemia Flashcards
Why is anaemia common in cats?
Cats good at masking illness - may be profound before clinical signs noted
Short RBC lifespan, lower RBC mass
Haemoglobin has low affinity for oxygen - may be profound before clinical signs noted
What are the clinical signs of anaemia?
Pale (or yellow) MMs
Lethargic, weak
Hyperdynamic pulses
Tachycardia, heart murmur
Tachypnoea
Enlarged lymph nodes and spleen
Pica
Describe the PCV of an acute anaemia.
Volume of blood loss equally reduces plasma and RBCs so PCV stays normal
Describe the PCV of a chronic anaemia.
Reduced RBC volume, increased plasma volume
So PCV decreases below normal
What are the key features of regenerative anaemia?
Reticulocytes >50x10^9/l
Anisocytosis
Polychromasia
Mean cell volume (MCV) increased
Mean cell haemoglobin concentration (MCHC) decreased
What are the key features of non-regenerative anaemia?
Reticulocytes <50x10^9/l
Normocytic
Normochromic
MCV normal
MCHC normal
Define anisocytosis.
Variation in RBC size
Define polychromasia.
Variation in RBC density of colour (haemoglobin)
Define hypochromic.
Pale (less haemoglobin per RBC)
Define nucleated RBC.
Earlier release from bone marrow
Define normocytic, microcytic and macrocytic.
Normocytic = normal size RBS
Microcytic =small RBC
Macrocytic = large RBC
Describe punctate reticulocytes.
Reticulocytes = immature RBCs released early into circulation
Occur in reasonable numbers in normal non-anaemic cats and so do not represent active regeneration
Can only be seen with new methylene blue stain
What is the best way to establish whether an anaemia is regenerative or not?
Absolute reticulocyte count (x10^9/l) = observed % reticulocytes x RBC count (x10^12/l) x 10
Which two confounding factors can make it harder to categorise anaemia?
Duration of anaemia
Concurrent disease e.g. FeLV, cat flu
What causes of haemorrhage can lead to a regenerative anaemia?
Trauma
Coagulopathies
Chronic blood loss from flea infestations/infected tumours/GI tract
What causes of haemolysis can lead to a regenerative anaemia?
Infection e.g. FeLV
Immune-mediated e.g. drugs, neoplasias, FeLV
Heinz body anaemia e.g. paracetamol/onion toxicity, lymphoma
Severe hypophosphataemia e.g. refeeding syndrome
Incompatible blood transfusions
Neonatal isoerythrolysis
What is Feline Infectious Anaemia?
Caused by mycoplasma haemofelis, transmitted by fleas
What are the clinical signs of FIA?
Pallor
Lethargy
Anorexia
Weight loss
Pyrexia
Dehydration
Jaundice (if severe acute)
How do we diagnose and treat FIA?
PCR for diagnosis
Treated with doxycycline (followed by food/water)
Describe non-regenerative anaemia.
Most anaemic cats have non-regenerative anaemia
Bone marrow fails to respond adequately to anaemia and does not produce new RBCs
Bone marrow sampling needed to determine cause of anaemia
What can cause a non-regenerative anaemia?
Disorders of the bone marrow (severe!)
Secondary to systemic disease e.g. neoplasia, FeLV, FIV, FIP, bacterial infections, chronic inflammation and chronic kidney disease
Describe blood transfusions as a supportive measure for anaemic cats.
Useful adjunct treatment for FIA and non-regenerative anaemias
Based on clinical grounds rather than a specific PCV cut-off (different effects with chronic/acute anaemia)
Describe erythropoietin as a treatment for anaemia.
Some success in cats with chronic kidney disease
Not all patients respond and there are a number of side effects
Newer recombinant human treatments are available that have lower development of severe side effects
Describe bone marrow stimulation as a treatment of anaemia.
Anabolic steroids sometimes used in first line treatment
May stimulate erythroid precursors in bone marrow
Prednisolone may be considered on the basis that an immune-mediated mechanism has been proposed in some cases of marrow failure
Can improve QOL and appetite of CKD cats
