Anal Fistulae
Issue Description
Canine anal furunculosis (perianal fistula) is a formation of an abnormal channel between the anal canal and the skin surrounding the anus. The continual
discharge of watery pus from the fistula can irritate the skin and result in itching, discomfort and pain.
Other Names
Canine Anal Furunculosis, Perianal Fistulae
Causes
While the precise cause of the disease is unclear, some German Shepherds seem to be unable to resist even superficial infections which may arise in the skin. This
may be the result of an ineffective immune response resulting in predisposition to the development of skin infections as a persistent problem. Additionally, the
conformation of the German Shepherd allows for the broad base of the tail to remain in almost continual contact with the anus, thereby spreading a thin film of
feces over the perianal region. Hence this is the site which is affected most frequently. Recent evidence, however, points to an immune-mediated process as the
underlying cause of this disease.
The anal sacs (scent glands) are usually involved in the disease process and are removed as part of the initial
treatment. It should also be emphasized that a dog's predisposition to the development of Perianal Fistulas is lifelong. Relapses, although uncommon, may
sometimes occur even after apparent care.
Symptoms
It is most common in German Shepherd and Irish Setter breeds. However, it has been seen in other breeds. Males outnumber females by 2 to 1. Clinical signs are
characterized by multiple draining tracts and ulcers immediately surrounding the rectum.
Animals may present pain and spasm when attempting to evacuate the
bowels (tenesmus), difficulty in defecation and constipation. Affected area is usually very painful. An association between perianal fistulas and inflammatory
bowel disease is suspected.
Clinical signs of anal furunculosis:
Pain or spasm when attempting to pass urine or evacuate the bowels (tenesmus)
Passage of red blood through the rectum
Constipation
Diarrhea
Ribbon like stool
Increased frequency of defecation
Perianal pus-filled discharge and/or bleeding
Perianal licking
Self mutilation
Perianal pain
Scooting
Offensive odor
Low tail carriage
Weight loss
Diagnosis
Diagnosis is based on physical examination and history. Sedation may be necessary to perform a thorough examination since the condition can be very painful.
Biopsy samples will confirm the diagnosis.
Treatment
In the past, treatment for perianal fistulas included surgical ablation (removal of the fistula) or deroofing (removal of the skin covering each tract). In
general, surgery has been replaced by the use of immunosuppressive drugs. The response to cyclosporine, prednisone, and tacrolimus has been encouraging.
Cyclosporine is generally considered to be the drug of choice and is typically used on a 16-week course of treatment. Surgery, once widely used, is presently
reserved for cases that involve the anal sacs or for selective cases that do not respond to medical management.
Prognosis
Regardless of the treatment used, the earlier the condition is diagnosed and treated, the better the outcome. In most cases the prognosis is guarded to fair,
understanding that recurrence is common. In more severe cases, and those involving surgery, fecal incontinence is a major concern.
The material and information on this website, including any merchandise, information or service provided through this website, is provided "as is"
with all faults and without warranty of any kind from the Furry Critter Network, expressed or implied. In no event shall the Furry Critter Network be
liable for any direct damages, special, incidental or consequential damages, lost profits, or any indirect damages arising from the use or inability
to use this website, even if the Furry Critter Network has been informed of the possibility thereof.