Bruising and Bleeding in Dogs

Abnormal bruising and bleeding arises with disorders of hemostasis (clotting). Clotting abnormalities are also called coagulopathies, because they reflect the inability of the blood to coagulate or clot. Bleeding from clotting disturbances may occur into the skin, the mucous membranes, and various internal organs, tissues, and body cavities. When the bleeding occurs into the skin, the membranes of the mouth, nose, eyes and external genitalia it may become visible to the owner. Bleeding into the intestinal tract may appear as hematochezia (fresh blood in the stools) or melena (dark, tarry stools). Bleeding into the urinary tract may be detected as blood in the urine (hematuria). 

The impact of such bleeding on the affected individual may be mild or severe depending on the degree of blood loss. Unexpected or unexplained bruising warrants examination of the animal by your veterinarian in order to determine if a clotting abnormality exists. Many clotting abnormalities are serious because they may predispose the animal to a life-threatening episode of bleeding.

The causes of bruising and bleeding can be classified as platelet disorders, vessel wall disorders, or clotting factor disorders. Platelets are small particles in the blood that begin the formation of a blood clot by clumping together at the site of any break in the blood vessel wall. Clotting factors are proteins in the blood that are responsible for further development of a clot after the platelets have initiated the process.

Platelet Disorders

Platelet disorders can arise when platelet numbers are decreased, or platelets fail to function properly. Platelet numbers are decreased when they are not produced adequately in the bone marrow, when they are destroyed, or when they are prematurely removed from the circulation. Dysfunction of platelets can occur as an inherited, congenital disorder, or may develop as an acquired condition later in life.

These disorders cause a decrease in the production of platelets:

Drugs toxic to the bone marrow

Infection of the bone marrow with certain bacteria, viruses, and rickettsia (e.g. ehrlichiosis)

Immune mediated destruction of the bone marrow        

Cancer of the bone marrow

Myelophthisis and myelofibrosis, which are scarring and disappearance of bone marrow cells

Excessive estrogen hormone influence on the bone marrow

These disorders result in increased platelet destruction:

Immune-mediated destruction of platelets

Certain drugs

Certain viral infections

These disorders cause increased removal of platelets from the circulation:

Ehrlichiosis in dogs

Vasculitis

Certain parasites

Certain disorders of the spleen

Disorders that affect the function of platelets include the following:

         

Congenital platelet function disorders

Certain drugs

Some infections

Kidney failure

Liver failure

Certain leukemias

Vascular Disorders

Vascular disorders usually result in abnormal bleeding by weakening the walls of the blood vessels. In some instances the underlying disease may also increase blood pressure, which aggravates any bleeding tendency. Disorders that increase the fragility of blood vessel walls include the following: 

Vasculitis – inflammation of blood vessels

Hyperadrenocorticism – a disease where the adrenal glands produce too much cortisone hormone in the body 

Diabetes mellitus – sugar diabetes

Uremia – an increase in waste products not cleared by diseased kidneys 

Clotting Factor Disorders

Inherited deficiencies of clotting factors that result in hemophilia         

Toxicity with warfarin or warfarin-like products that antagonize Vitamin K          

Liver disease that prevents the manufacture of clotting factors 

Disseminated intravascular coagulation (DIC), which is widespread bleeding due to the consumption of platelets and clotting factors

Von Willebrand's disease, which arises from a deficiency of a factor needed for proper platelet function

What to Watch For

Blood in the urine or stool

Nose bleed (epistaxis)

Bruises or swelling on or under the skin

Pin point or blotchy hemorrhages on the gums of the mouth

Pinpoint or blotchy hemorrhages on the membranes of the vulva and penis

Pinpoint hemorrhages on the whites of the eyes or the inside of the eyelids

Bleeding into the front chamber of the eye 

Difficulty breathing with bleeding into the lungs or chest cavity

Abdominal distension with bleeding into the abdomen

Weakness, depression

Pale gums from anemia

Excessive or unrelenting bleeding from a cut or wound

Swollen and painful joints from bleeding into the joints

Diagnosis

There are many tests that may be recommended for the patient with abnormal bruising or bleeding. The following is a list of the tests that are often performed initially:

Complete blood count (CBC)

Platelet count

Biochemical profile

Urinalysis

Thoracic (chest) and abdominal radiographs (x-rays) 

Fecal tests

Coagulation studies that measure how long it takes for the blood to clot

Serologic tests for infectious diseases that can affect clotting

Abdominal ultrasonography

Bone marrow aspiration and cytology

Von Willebrand's factor assay 

Assays of clotting factors

Treatment

There are several things your veterinarian might recommend to treat the patient with bruising/bleeding symptomatically while the diagnostic work up is underway. These supportive measures include the following: 

Discontinue any medications that may cause a bleeding problem.

Minimize activity to reduce the risk of even minor trauma.

If an animal is severely anemic or weak from excessive bleeding, it may be necessary to hospitalize the patient for the administration of intravenous fluids, transfusions of blood products, and institution of other stabilizing measures, such as oxygen therapy, vitamin K therapy, and administration of antidotes to toxins.

Home Care

Any sign of bruising or bleeding should be evaluated in a timely fashion by your veterinarian. Administer only medications that your veterinarian has recommended and do not allow your pet to have exposure to rat poison and other toxins that can cause bleeding.