Epistaxis (Nose Bleed) in Dogs
Dr. Douglas Brum
Epistaxis or nasal bleeding is generally caused by either an acute (sudden) event, or by more insidious chronic problems. Acute epistaxsis many times is the result of nasal fractures or lacerations caused by traumatic episodes. If there is no history of trauma, acute bleeding is often caused by the sudden erosion of a nasal blood vessel due to some primary problem within the nasal cavity, or perhaps metabolic conditions. Many times, acute epistaxis will occur, but the underling condition is a chronic or long-standing condition. Tumors, foreign bodies, and tooth root abscesses often present with acute epistaxis, yet the problem may have been present for some time.
Intermittent recurrent or chronic nosebleeds are common as blood clots form to stop the bleeding. Clots dislodging or new blood vessels becoming affected may cause future episodes of bleeding. It is also important to note whether the epistaxis is unilateral (one sided) or bilateral (both sides). Tumors, foreign bodies, and tooth root abscesses are usually unilateral. Infections and metabolic conditions are usually bilateral. If the animal has been losing weight or has been ill for some time before epistaxis is noted, it may indicate a more serious condition. It is rare for the volume of blood loss from the nose to be life threatening, rather the epistaxis is an important clinical sign that warrants further evaluation. Unless caused by trauma, epistaxis is a significant finding that often will recur if a definitive diagnosis is not reached.
The most common causes of epistaxis are:
Trauma, such as nasal fractures caused by automobile accidents, bite wounds and nasal lacerations caused by sharp objects
Nasal foreign bodies. Epistaxis will occur if a nasal foreign body punctures a blood vessel. Inflammation associated with a nasal foreign body can cause blood-tinged nasal discharge.
Dental disease. A tooth root abscess may develop if dental disease is severe or a fractured tooth becomes infected. The roots of the teeth in the maxilla (upper jaw bone) are very long. If infection develops at the base of the tooth root, it may cause swelling and break into the nasal cavity. Epistaxis occurs because the nasal blood vessels are affected. A swelling on the bridge of the nose or under the eye may be observed in a pet with a tooth root abscess.
Nasal tumors are a common cause of unilateral (one-sided) epistaxis in older dogs. The most common tumors in affected dogs are adenocarcinoma, chondrosarcoma, fibrosarcoma, osteosarcoma and squamous cell carcinoma.
Bacterial, fungal and parasitic infections may cause epistaxis. Only severe bacterial infections are likely to cause epistaxis. Bacterial infection may be due to trauma or a foreign body that is no longer present. Aspergillosis in dogs is a fungal infection that affect the nasal cavity and may lead to epistaxis. Nasal parasites (e.g., nasal mites in dogs) also can cause epistaxis but episodes of sneezing and rubbing at the face are more common symptoms of nasal mite infection.
Many bleeding disorders can cause epistaxis. Bleeding at other sites also may be observed. Thrombocytopenia (low platelet count) is a common cause of such bleeding problems. Platelets are blood cell fragments that are vital to the clotting process and may be decreased by several different disorders including tick-borne diseases caused by a type of bacteria called rickettsia. Von Willebrand's disease is a clotting factor deficiency that may affect several breeds of dogs (notably Doberman pinschers) and can lead to abnormal platelet function and prolonged bleeding after minor trauma or surgical procedures. Rodenticides containing vitamin K antagonists are frequently the cause of generalized bleeding in dogs because they interfere with activation of several clotting factors by vitamin K.
Hyperviscosity (thickening of the blood) can result from extremely high concentrations of blood proteins in pets with certain diseases. The high protein concentration leads to poor platelet function and abnormal coagulation. Occasionally, epistaxis is the first symptom of this problem. Common causes of hyperviscosity syndrome are multiple myeloma (overproduction of antibody proteins by malignant antibody-producing plasma cells), lymphoma (cancer of lymphoid tissue and lymphocytes) and erhlichiosis (a tick-borne rickettsial disease).