Veterinary CPD webinar – Understanding Anaemia in Dogs and Cats: A Comprehensive Guide

What is Anaemia?

Anaemia occurs when there is a decreased red blood cell mass in the body, which can be measured by low haemoglobin, haematocrit, or red blood cell count. In dogs and cats, non-regenerative anaemia is more common than regenerative anaemia. Severity matters; a mild anaemia may be incidental, while severe anaemia can significantly impact prognosis.

Causes of Anaemia

There are three main mechanisms:

• Decreased production – When the bone marrow isn’t producing enough red blood cells.
• Increased loss – Blood loss from trauma, gastrointestinal bleeding, or parasites.
• Decreased lifespan – Premature destruction of red blood cells, often due to haemolysis.

How Anaemia Presents

Symptoms often reflect reduced oxygen delivery:

• Pale gums and mucous membranes
• Weakness and fatigue
• Exercise intolerance
• Rapid breathing or heart rate
• Pica (abnormal eating habits) in chronic cases
• Sudden collapse or loss of appetite in severe cases

Diagnosing Anaemia

Diagnosing anaemia requires a careful, stepwise approach:

• Confirm anaemia: Laboratory machines can be inaccurate. A fresh blood smear is invaluable for examining red blood cell shape, inclusions, and evidence of regeneration or destruction.
• Determine type:
  • Regenerative: Bone marrow responds appropriately, usually due to blood loss or haemolysis.
  • Non-regenerative: Bone marrow fails to produce enough red blood cells, which may be caused by chronic disease, nutrient deficiencies, or bone marrow disorders.
• Assess red blood cell indices: Tools like MCV, MCHC, and RDW help classify anaemia as microcytic, macrocytic, hypochromic, or normochromic.
• Investigate underlying causes: Comprehensive diagnostics may include blood chemistry, urinalysis, imaging, infectious disease testing, iron panels, vitamin levels, and occasionally bone marrow evaluation.

Common Types of Anaemia

• Regenerative anaemia: Often due to bleeding or haemolysis. Reticulocytosis (immature red blood cells) indicates bone marrow response.
• Non-regenerative anaemia: Can result from chronic inflammation, iron deficiency, nutrient deficiencies, kidney disease, or bone marrow suppression.

Treatment and Management

• Treat the underlying cause whenever possible.
• Blood transfusions may be needed in severe anaemia.
• Supportive therapies may include iron supplementation (if deficiency is confirmed), EPO-stimulating agents, vitamins, and medications for immune-mediated anaemia.
• Always monitor for complications such as hypercoagulability or secondary organ involvement.

Key Takeaways

• Anaemia is rarely the primary disease; it often signals an underlying problem.
• Thorough characterisation of anaemia is crucial for correct diagnosis and effective treatment.
• Always consider species, breed, age, and individual variation when interpreting lab results.

Understanding anaemia allows veterinarians to see beyond the numbers and address the root causes, improving outcomes for pets.