Anaemia SA

Classification

·    Decreased haematocrit (Hct), packed cell volume, or haemoglobin

Clinical signs

·    Inadequate perfusion/oxygenation – pale MMs, lethargy, exercise intolerance

·    Compensatory mechanisms – tachycardia, tachypnoea

·    Poor pulse quality, soft heart murmur

·    CS related to underlying pathology, e.g. splenomegaly, lymphadenopathy, pain, pica, icterus, melena

Categorising

·    Based on PCV (<20% in dogs, <15% in cats = severe)

·    RBC indices – MCV (size), MCHC (colour)

·    Regeneration?

o  Usually based on presence of reticulocytes – suggest bone marrow is producing more RBCs

o  Anisocytosis – variably sized RBCs

o  Nucleated RBCs (seen earlier than reticulocytes)

o  Basophilic stippling

o  Howell-Jolly bodies – nuclear remnants

o  Heinz bodies

·    Other haematology clues:

o  Acanthocytes – fragmentation injury (clots, DIC), fragile RBCs (iron deficiency)

o  Echinocytes – drug exposure (furosemide), electrolyte disturbance, renal disease, snake venom

o  Schistocytes – mechanical injury, vascular damage (e.g. DIC, glomerulonephritis, vasculitis, PSS, haemangiosarcoma

o  Spherocytes – IMHA

Causes of anaemia

Regenerative

·    Haemorrhage

o  Acute – traumatic wounds, blunt force, D+/V+, epistaxis, DIC

o  Chronic – melena, chronic/multiple small wounds, GI/blood borne parasitism (babesia)

·    Haemolysis

o  IMHA – reaction to: normal self-antigen, infectious agent bound to cell surface, or non-biological ag bound to cell surface

·    Non-regenerative

o  Decreased bone marrow production of RBCs

§ Intra-marrow – infection, chronic damage, neoplasia, lack of raw materials (iron deficiency)

§ Extra-marrow – CKD, excessive oestrogen (EPO suppressor), FeLV

o  Pre-regenerative anaemia – bone marrow takes few days to release reticulocytes

o  Chronic haemorrhage/haemolysis (initially regenerative but body now unable to cope)

Management

·    Triage, emergency treatment/stabilisation

o  Oxygen therapy

o  Temperature management (decrease pyrexia or warm hypothermic animal SLOWLY)

o  Analgesia

o  Emergency surgery – bleeding haemangiosarcoma, splenic rupture, arterial bleeds

·    Fluid therapy +/- blood transfusion

o  IVFT – treat hypovolaemia, address tissue perfusion

o  Blood products – whole blood, pRBCs, FFP/FP, platelets

·    Treat symptoms of specific disease

o  Haemorrhage – diagnose + tx coagulopathy, physically stop bleeding, address internal causes (e.g. GI disease, intra-cavity bleeding)

o  Haemolysis – glucocorticoids to treat IMHA +/- cyclosporin, azanthioprine

o  Infectious disease

§ Babesia – doxycycline, parasite control once recovered (seresto)

§ Ehrlichia – SNAP test to dx, doxycycline to tx

o  Oxidative damage, e.g. heavy metals, onions/garlic, paracetamol – N-acetylcysteine

o  Bone marrow

Aplastic anaemia

·    Due to failure of myeloid cell production

·    Usually secondary to toxicity, adverse drug reaction or infection (e.g. FeLV, parvovirus, Ehrlichia)

·    Clinical signs: anaemia (if loose RBCs), clotting disorders (if loos platelets), reduced immunity (if loose neutrophils)