Blood Thickening in Dogs

Blood thickening, or polycythemia vera, affects your dog’s entire body because the thicker blood causes problems in all of the major organs depending on the severity of the disease. Too many blood cells slows down the circulation, which reduces the amount of oxygen and nutrients in your dog’s body. It also affects the body’s ability to circulate hormones, causing hormone deficiency and hypoxia. The thickened blood from any of the types of polycythemia vera will eventually cause clotting, which can cause heart attack, stroke, and death if not treated promptly, so it is important to make an appointment with your veterinarian right away.

Blood thickening (polycythemia vera) is a blood disorder that causes too many red blood cells to form in your dog’s circulatory system. There are four types of blood thickening, which are transient, primary absolute, secondary absolute, and relative. This is a serious disease in dogs that can be caused by a number of different things and, left untreated, will eventually cause heart failure and death.

Since there are several different types of thickening of the blood, the symptoms will vary. They may come on gradually, making it more difficult to notice the problem in the first place. Since you know your pet the best, you are your dog’s best examiner, noticing when he or she just is not acting like their usual self. The four different types of polycythemia vera each have their own individual symptoms as well as similar symptoms that may overlap.

Transient

• Changes in behavior
• Sluggishness
• Loss of appetite
• Weight lossNose bleeds
• Unsteadiness
• Sneezing
• Drinking less water
• Lack of energy

Primary and Secondary Absolute

• Vomiting
• Appetite loss
• Excessive sleeping
• Losing weight
• Pale gums
• Weakness
• Tiredness
• Swollen abdomen

Relative

• Bleeding from nose
• Low energy level
• Vomiting
• Diarrhea
• Sleepiness
• Increased urination
• Blood in urine
• Blood in stool

 Types

•  Transient Polycythemia Vera comes and goes with flare-ups and remissions
• Primary Absolute Polycythemia Vera is a chronic disease with unknown origin
• Secondary Absolute Polycythemia Vera is caused by an underlying condition
• Relative Polycythemia Vera is caused by the loss of plasma and is usually temporary

Transient Polycythemia Vera is caused by the spleen contracting from any emotion such as:

• Irritation
• Anger
• Anxiety
• Fear
• Alarm
• Thrill
• Shock
• Surprise 

Primary Absolute Polycythemia Vera is an overproduction of the red blood cells by the bone marrow. This is usually caused by an uncommon bone marrow disease called Myeloproliferative Neoplasms disease.

 Secondary Absolute Polycythemia Vera presents from a decrease of oxygen in your dog’s blood, which is called hypoxemia. The cause of this disorder is one of several things:

• Serious heart problems
• Pulmonary disease
• Decreased blood to the kidneys
• Serious hormonal disorder

 Relative Polycythemia Vera is increased red blood cells caused by many underlying disorders, such as:

• Severe dehydration
• Loss of blood (injury)
• Vomiting
• Diarrhea

• Bone marrow examination from fine needle aspiration
• Blood work
• Urinalysis
• Auscultation
• Digital Radiographs (x-rays)
• Electrocardiography
• Echocardiography
• Selective angiography
• Contrast echoaortography
• Neurologic examinations
• Abdominal ultrasonography
• IV urography
• CT scan
• MRI

Treatment of blood thickening depends on the type of polycythemia vera your dog has. Although some of the treatments are similar, the administration may be different. The main goal is to thin the blood, but the way to do that varies with each disorder.

 Transient Polycythemia Vera

Transient polycythemia vera usually does not require any treatment because the condition is temporary and will resolve itself when your dog is calmed down.

 Primary Absolute Polycythemia Vera

Treating primary absolute polycythemia vera is more difficult than the others, but the end result needs to be the same: thinning out the blood. Phlebotomy is the best course of action for most cases, which is basically just draining out some blood while administering isotonic fluid. This can be done in the office and your dog can go home the same day in most cases. The veterinarian will probably do several phlebotomy treatments over a period of months to get your dog’s system back under control. The procedure may have to be repeated once in a while if your dog’s blood starts thickening again.

 If the blood levels do not level out from phlebotomy, the veterinarian may try medication, such as hydroxyurea. Chemotherapy medications can also be useful in severe conditions. These drugs will decrease the red blood cell production, but careful monitoring must be done during treatment.

 Secondary Absolute Polycythemia Vera

The underlying illness has to be treated to treat secondary absolute polycythemia vera. If the condition is severe enough the veterinarian may use phlebotomy to thin your dog’s blood right away. This will allow for more time to get tests done in order to find the primary cause of the problem.

 Relative Polycythemia Vera

Since relative polycythemia vera is associated with dehydration or injury, the first thing your veterinarian will do is administer IV fluid or subcutaneous fluid just under the skin. Your dog may be sedated until the blood level returns to normal because agitation or anxiety can hinder the treatment. Once your dog’s blood level is normal you can bring him home but follow-up appointments and blood tests will be required.

In most of these cases, the prognosis is good if the condition is caught and treated before any major organ damage is done.