Acute Myeloid Leukemia in Dogs

The abnormal white blood cells in the peripheral blood are not able to fight off bacterial pathogens and they also impair the body’s ability to produce red blood cells and platelets. Acute Myeloid leukemia can disrupt the normal functions of the dog’s liver, kidneys, heart, spleen, lymph nodes and central nervous system. The disease is more common in young and middle-aged dogs. AML is a very aggressive disease.

Acute myeloid leukemia is a malignant neoplastic disease, which occurs suddenly. AML is a type of cancer that originates and multiplies in the bone marrow.  Acute myeloid leukemia causes the rapid production differentiated (abnormal) white blood cells in the peripheral blood. Peripheral blood is the circulating blood in the body, which carries nutrients and helps to fight off diseases.

Symptoms may include:

• Lethargy
• Weakness
• Tires easily
• Nose bleed
• Lack of appetite
• Pale gums
• Loss of color in the inner eyes
• Depression
• Increased water intake
• Shifting leg lameness
• Impaired coordination
• Nystagmus (rapid involuntary movements of the eyes) 
• Anemia
• Dehydration
• Elevated heart rate
• Labored breathing
• Neutropenia - low count of the neutrophils; a type of white blood cell count
• Thrombocytopenia - low platelet count

The cause of acute myeloid leukemia is not fully understood and there is no concrete known cause for the disease. Veterinary experts suggest that contributors to leukemia in dogs may occur from exposure to radiation, chemicals, toxins and viruses.

The veterinarian will want to go over the patient’s medical history.  If your dog has been seen by another veterinarian, it is recommended that you bring his medical records and any current medications or supplements he may be on.  During the consultation the veterinarian will want to know what clinical signs you have observed and when they started.   

The veterinarian will perform a physical exam, which may include taking the patient’s vitals, check the color of his gums and inner eyes.  He may also want to palpate the dog’s stomach and limbs.  The veterinarian may suggest taking a complete blood count, serum chemistry panel and a urinalysis. 

A complete blood count will measure the white cell count (leukocyte count), white blood cell differential (neutrophils, lymphocytes, monocytes, eosinophils and basophils), red blood cell count (erythrocyte count) and the platelet count. High numbers of white blood cells and abnormal blood cells may be an indication of leukemia.  A complete blood count can also help determine if the patient is anemic or has a bacterial infection.  Anemia may be caused by the inability of the bone marrow to produce new red blood cells.

The serum chemistry panel will determine blood glucose, blood urea nitrogen (BUN), calcium, bilirubin, cholesterol, sodium, alkaline phosphatase, potassium, total blood protein and bilirubin. These particular levels help evaluate the patient’s organ functions.  

A urinalysis may be obtained from the patient by cystocentesis (a needle is used to aspirate urine from the bladder), catheterization (a catheter is passed through the urethra into the bladder) or by mid-stream free-flow (collected in a sterile container while your dog is urinating). A urinalysis can determine kidney failure, urinary tract infections, occult blood, crystals and glucose levels. 

The veterinarian may also suggest a bone marrow aspiration and biopsy. The patient will need anesthesia or a sedative to be administered before the procedure. The technique involves using a hollow needle to obtain a bone marrow sample. The sample is sent to a pathology lab to determine if the patient has acute myeloid leukemia.

If the complete blood count determined that the patient is severely anemic, a whole blood transfusion may be necessary. Chemotherapy is usually recommended for dogs diagnosed with acute myeloid leukemia. Chemotherapy involves giving the patient anti-cancer drugs, which are meant to kill cancer cells. They are administered via injection or orally. Chemotherapeutic treatments may have side effects such as vomiting, nausea, infections, minor hair loss, appetite changes and diarrhea.

The veterinarian may suggest that your dog be hospitalized during chemotherapy; this will provide him 24/7 intensive care. Supportive therapy may also include administering fluids, broad-spectrum antibiotics and nutritional supplements. There are alternative therapies such as homeopathic treatment, herbs and acupuncture that may help with the symptoms of AML.

The patient will require follow-up visits to monitor his progress during chemotherapy and after the treatment.  The recovery prognosis for acute myeloid leukemia is guarded. Repeat blood work will be necessary to check on the levels of white blood cells and organ functions. Medical care for acute myeloid leukemia may prolong your dog’s lifespan. The dog’s quality of life must be considered.  The veterinarian may suggest euthanasia if your dog does not respond to the treatment plan.