Anaemia means a reduced number of red blood cells (RBC’s), haemoglobin, or both. It is not a specific disease but the result of some other disease process.
How is anaemia diagnosed?
The most easily observed clinical sign of anaemia is a loss of the normal pink colour of the gums. Anaemic dogs also have little stamina so they seem listless or tired. Pale gums and lethargy indicate the need to perform blood tests.
There are several tests that are performed on the blood sample to diagnose anaemia. The most common test is the packed cell volume (PCV). A blood sample is processed in a centrifuge to separate the red blood cells from the plasma (the liquid part of the blood). Once separated, the sample is measured to determine what percentage of the sample is made up of red blood cells. Thirty-five to fifty-five percent of the normal dog’s blood will be red blood cells. If the PCV is below 35%, the dog is anaemic. Others tests to determine anaemia include the red blood cell count and the haemoglobin count.
What other tests are important when a dog is anaemic?
It is important to know if the bone marrow is producing an increased number of new red blood cells to replace those lost. Often, this can be determined by a study of the stained blood smear. The presence of increased numbers of immature (young) red blood cells called reticulocytes usually means the bone marrow is responding to the need for more red blood cells.
A careful study of the blood smear is also important to look for parasites that might be causing red blood cell destruction and abnormal cells that could indicate leukaemia (high white blood cell count).
Biochemical profiles and urinalysis are also important tests for anaemic dogs. These tests evaluate organ functions and electrolyte levels. They will often provide important information about the overall health of the dog.
The coat is also carefully examined for blood-sucking parasites such as fleas and ticks. A faecal exam is important to identify the presence of parasites in the intestinal tract that might be causing blood loss.
What diseases cause anaemia?
There are many diseases that cause anaemia. These are grouped into 1) diseases that cause blood loss, 2) diseases that cause haemolysis (red blood cell breakdown or destruction), and 3) diseases that decrease the production of red blood cells.
What diseases of dogs cause blood loss?
The main causes of blood loss in dogs include:
- Trauma or injury that severs blood vessels or damages internal organs, causing persistent bleeding
- Heavy burdens of parasites such as fleas, ticks and hookworms
- Tumours of the intestinal tract, kidneys, urinary bladder and spleen.
- Diseases that prevent proper blood clotting (eg brown snake bite and ingestion of rat bait) or damage or reduce the number of blood platelets.
What diseases of dogs cause haemolysis?
The main causes of haemolysis in dogs include:
A. Autoimmune disease
B. Blood parasites
C. Chemicals or toxins including onions and some snake venoms
D. Neoplasia (cancer)
What diseases of dogs prevent red blood cell production through bone marrow suppression?
The main causes of bone marrow suppression that result in decreased red blood cell production include:
A. Any severe, chronic disease
B. Very poor nutrition or nutritional imbalances
C. Autoimmune disease
E. Chemicals or toxins
F. Neoplasia (cancer)
There has been no mention of iron deficiency. Why not?
Iron deficiency anaemia is not common in dogs and is usually secondary to some form of chronic blood loss. It is mainly seen in puppies with severe hookworm or flea infections.
How are anaemic dogs treated?
If your dog’s anaemia is so severe that it is life threatening, a blood transfusion will be needed. This may be performed immediately after a blood sample is taken for diagnostic testing purposes. The main purpose of a blood transfusion is to stabilize the dog long enough that a determination of the cause of the anaemia can be made.
Further treatment will be determined once the underlying disease causing the anaemia has been diagnosed.