Medullary aplasia is a bone marrow disease that can affect dogs. It consists of a deficit of all or some of the precursors of the cell lines of white blood cells, red blood cells and platelets, so the symptoms that the dog will present will vary depending on what is lacking. For example, if you lack red blood cells you will have anemia. If it's white blood cells, you'll get infections, and if it's lacking platelets, you'll bleed.
The origin of canine bone marrow aplasia can be very diverse and includes everything from infections to drugs, toxins or diseases. Diagnosis is simple, but treatment is complicated, causing the prognosis of the disease to be considered reserved or poor in most cases.
Keep reading this article on our site to learn about bone marrow aplasia in dogs, its symptoms and treatment.
What is bone marrow aplasia?
Medullary aplasia or bone marrow aplasia is called hypoplasia of the erythroid, myeloid and megakaryocytic lines, precursors of blood cells that originate in the bone marrow. Due to this, there is a reduction of red blood cells or erythrocytes, white blood cells or leukocytes or platelets in the peripheral blood. The bone marrow aplasia is total if all the precursors are affected or partial if only some of them are. In addition, the absence of hematopoietic tissue is replaced by adipose tissue, which reaches up to 95%.
Causes of bone marrow aplasia in dogs
Marrow aplasia in the canine species can be produced by the following causes:
- Drugs: chemotherapy drugs, azathioprine, trimethoprim/sulfadiazine, exogenous or endogenous estrogens, phenylbutazone, cephalosporins, phenothiazine, captopril or chloramphenicol.
- Environmental toxins: insecticide, benzol, varnish or paint.
- Microorganisms: Ehrlichia canis or canine parvovirus, which infects progenitor and proliferative cells in the bone marrow.
- Hematopoietic neoplasia.
- Chronic renal insufficiency.
In addition, a congenital pure red cell aplasia called Diamond-Blackfan anemia has been described in dogs, which affects young specimens. It causes an absence of erythroid precursors, but the others are intact. Also known is a idiopathic or primary aplasia, apparently of immune-mediated origin, since it responds to corticosteroid therapy.
Symptoms of bone marrow aplasia in dogs
The clinical picture of canine bone marrow aplasia will vary according to the degree of cell involvement, with total pancytopenia being more serious, as they will cause symptoms related to the lack of red, white and platelet cells, with the consequences this has for the affected dog.
The symptoms associated with erythrocyte aplasia due to a lack of red blood cells are those derived from a anemia. Highlights:
- Pale mucous membranes.
- Tachycardia.
- Tachypnea.
- Fatigue.
- Weakness.
- Exercise intolerance.
- Palpitations.
When white blood cells, immune cells responsible for the immune response, are missing, the dog will be susceptible to all kinds of infections.
If platelets are missing, dogs will have a tendency to suffer hemorrhages, since platelets are involved in coagulation of the blood. These hemorrhages can be minor, such as oral or nasal bleeding, or, in the worst cases, they will occur in internal organs, such as the digestive system or the brain, putting the dog's life at risk.
Diagnosis of bone marrow aplasia in canines:
The diagnosis of bone marrow aplasia is achieved with a blood test, which allows the number of red and white blood cells and platelets to be assessed, which in this disease will be diminished. Acute leukemias should be included in the differential diagnosis.
Once the reduction is confirmed, a bone marrow sample must be taken by aspiration or biopsy:
- Aspiration samples allow you to assess the individual shape of cells and determine the myeloid-erythroid ratio.
- The biopsy indicates the structure of the marrow and its global cellularity. This is the technique of choice in cases of hypocellular marrow or marrow that has been replaced by fatty tissue. In this sample, the absence of hematopoietic cells will be observed.
Bone marrow sample collection
Bone marrow samples are taken from dogs at the following locations:
- Proximal epiphyses of the humerus and femur.
- Iliac crest.
- Ilium wing.
- Ribs.
- Breastbone.
Treatment of bone marrow aplasia in dogs
The treatment of bone marrow aplasia in dogs will depend on the cell types affected, but, in general, it is as follows:
- Antibiotics and asepsis in cases of leukocyte aplasia to prevent infectious diseases.
- Stem cells, for its immunomodulatory and anti-inflammatory activity. They are responsible for repopulating the bone marrow due to their ability to differentiate into blood cells.
- Hematopoietic growth factors.
- Immunoglobulins.
- Antilymphocyte or antifungal globulin.
- Cyclosporin A.
- Corticosteroids.
- Bone marrow transplant, if it is a young dog with severe bone marrow aplasia.
Prognosis of bone marrow aplasia in dogs
Canine bone marrow aplasia generally has a poor prognosis, since it is a pathology in which, in numerous cases,, the response to treatment is poor. Consequently, it can lead to the death of our dog, especially if it does not respond to immunosuppression or the origin of bone marrow aplasia is not detected.
