If the patient is a German shepherd, a perianal fistula is most often diagnosed on the basis of clinical presentation and physical examination alone. If the dog is another breed, other causes based on clinical signs should be ruled out first. For example, for a Shih Tzu with purulent anal discharge and intracellular cocci seen with cytology, the proper first step would be treating the infection to see if the draining tract resolves. Taking a biopsy sample of the draining tract can help detect other causes (e.g., cancer, allergies, foreign body) and obtain a definitive diagnosis. However, although biopsy is the best way to confirm a diagnosis, it is rarely performed due to the potential complications, similar to the complications of surgery discussed below.
As mentioned previously, a thorough rectal examination should be performed to identify any other associated abnormalities in the region. Because of the pain and discomfort of this disease, some patients may require sedation before they can tolerate a full rectal examination. Probing the draining tracts with a cotton-tipped applicator or something similar can help determine the depth of the draining tracts. Clinical improvement can be monitored by measuring the depths of these tracts. Depending on disease severity and duration, rectal examination can reveal no abnormal findings internally or severe fibrosis. The fibrosis can be identified as thickening of the perianal region with the possibility of anal strictures. For all of these patients, thorough palpation and expression of the anal sacs should be performed, which help rule out an anal gland abscess and determine whether the perianal fistula(s) communicate with the anal sac. In addition, the draining tracts can be flushed by using a tomcat catheter and sterile saline to determine whether the tracts are communicating with each other or if there is involvement with the anal sac.
Differential diagnoses vary greatly, depending on the presenting clinical signs. If the only signs noted are perianal pruritus, then other differentials include allergic dermatitis (atopic dermatitis and adverse food reaction) and anal sac abscess. If the patient has tenesmus and hematochezia only (no draining tracts or visible fistulas), the primary differentials become gastrointestinal conditions (e.g., inflammatory bowel disease, intestinal parasites, rectal strictures). If concurrent diseases are not addressed, treatment of the perianal fistula will not resolve all clinical signs.
Perianal fistulas, also known as anal furunculosis, can be severely debilitating in dogs. If not treated appropriately and in a timely manner, they can progress to irreversible changes to the rectum and anus, and in some cases, ultimately lead to euthanasia.
Depending on the therapy instituted, most patients will start to show clinical improvement within a few weeks. The fistulas may not be completely healed over, but other clinical signs should improve within that time. Due to the presumed immune-mediated nature of this disease, most dogs will require some sort of long-term therapy to keep the perianal fistula in remission.
The term “ACVS Diplomate” refers to a veterinarian who has been board certified in veterinary surgery. Only veterinarians who have successfully completed the certification requirements of the ACVS are Diplomates of the American College of Veterinary Surgeons and have earned the right to be called specialists in veterinary surgery.
Dogs that have cryosurgery or laser surgery will have open raw wounds for several weeks that will require daily gentle cleaning to remove dead tissue, bacteria, and fecal material from the area. Laxatives (stool softeners) such as lactulose may be added to the treatment, especially in dogs with severe pain during defecation. Some of these pets will need to wear an e-collar at all times in order to prevent self-mutilation.
A complete physical examination must include digital rectal examination, since infection or obstruction of the anal sacs can also cause perianal fistulas (Figures 1 and 2). Your pet may need to be sedated if painful. Cell or tissue samples from the anal sacs or fistula may be collected for microscopic examination (aspiration cytology or histopathology) or for bacterial culture and sensitivity.
Unfortunately, perianal fistulas may require lifelong medical management with special diets and drugs that suppress the immune system. These drugs can have serious side effects and should never be combined with any other medications (including those for arthritis) unless approved by your primary care veterinarian. Prognosis for initial healing early lesions is good; however, recurrence is common, particularly in dogs with moderate to severe disease. Chronic damage to the perineal region by perianal fistulas or after multiple surgeries may affect the nerve supply to the area, leading to fecal incontinence (when animals are not able to control when/where to defecate).
Perianal fistulas are tunnel-like formations in the skin and deeper tissues that surround the anal area of dogs. The lesions vary in severity but at first appear as small oozing holes in the skin. These holes may become wide and deep and surround the entire circumference of the anus. Although this condition can occur in any dog, German shepherds are most commonly affected. Position of their tail, which is often carried low between the hip bones, covering the anus, is thought to be a predisposing factor. Perianal fistulas may cause severe pain and discomfort and, if not controlled, may be responsible for a dramatic reduction in quality of life. Affected dogs may have concurrent chronic diarrhea because of inflammatory bowel disease; in fact, the two conditions may be related. This disease shows many similarities to Crohns disease in people. Signs and Symptoms:
The expense associated with drugs and or surgery can be devastating to owners whose dogs suffer this condition. The drugs used to treat this condition (usually required long-term) are often prohibitively expensive at $200 to $500 a month. Surgical interventions are also expensive, more so because these surgeries are almost always undertaken by highly trained, board-certified veterinary surgeons. $2,000 to $5,000 would be the typical cost for such a procedure.
Dr. Becker: What is Perianal Fistula?
Anal furunculosis (also called perianal fistulas) is a distressing condition commonly affecting German Shepherd dogs and occasionally other breeds. The problem is one of chronic deep infection, inflammation, discharges and ulceration around the tail base and anus. The condition may progress to involve a large area around the back end of the dog. It can be very difficult to cure or control but recent advances in treatments are proving encouraging.
[/vc_column_text][/vc_column][vc_column width=”1/3″][vc_single_ =”1362″ img_size=”full” alignment=”center”][/vc_column][/vc_row][vc_row][vc_column][vc_tta_accordion active_section=”0″ collapsible_all=”true”][vc_tta_section title=”What causes anal furunculosis?” tab_id=”1534168194114-3395fe9a-0ce0″][vc_column_text]No-one really understands what causes the condition to develop. It is more common in dogs with the broad tail base and low tail carriage typical of German Shepherds. This conformation may result in poor ventilation and increased humidity of the anal area. Faecal bacteria may persist in this environment increasing the risk of infection of hair follicles and hormone glands in this area.
Underlying problems with the immune system may also play an important role. The disease has also been linked to inflammatory bowel disease and colitis. If your dog has diarrhoea they may be at more risk of developing anal furunculosis.[/vc_column_text][/vc_tta_section][vc_tta_section title=”How would I know if my dog has anal furunculosis?” tab_id=”1534168194187-34ed65ef-9330″][vc_column_text]Anal furunculosis is very irritating and dogs with this condition will frequently lick their hind end. You may notice that your dog shows discomfort or difficulty when passing faeces. Other signs of illness such as weight loss irritability or depression due to pain are seen in severe cases.
The tell-tale signs are of matted hair, odour, bleeding and discharges from the anal area. However your dog may not let you look closely if the condition is very painful. It should be possible for your vet to make a diagnosis of anal furunculosis from looking at the diseased area (but they may need to sedate your dog for close examination). In a few cases biopsies are needed to be certain of the diagnosis.[/vc_column_text][/vc_tta_section][vc_tta_section title=”How is anal furunculosis treated?” tab_id=”1534168242490-6f98c354-492f”][vc_column_text]This is a difficult disease to treat and although several types of treatment are available none is 100% effective. The diseased tissue can be removed at surgery – often, extensive treatment is needed and this may need to be repeated. If extensive surgery is performed there is a risk of nerve damage which can result in incontinence. Some surgeons advocate amputation of the tail to improve ventilation or removal of the anal sacs.
Recently, encouraging results have been achieved using drugs designed to alter the function of the immune system, and this may prove to be a very effective treatment for anal furunculosis.[/vc_column_text][/vc_tta_section][vc_tta_section title=”Is there anything I can do at home to help in treatment?” tab_id=”1534168260845-7228a594-f89f”][vc_column_text]Yes, check with your veterinary surgeon first, but many dogs with anal furunculosis are greatly helped by hydrotherapy. This involves the use of a shower attachment or garden hose to direct water over the affected area under the tail once or twice a day. The water should be lukewarm or cool, under moderate pressure.
Start gradually and gently and build up as your dog gets used to this treatment. For this to be effective, each session should last at least 15 minutes. A tail bandage applied to the tail will stop this getting too wet. This treatment can have a very good effect if carried out diligently every day.[/vc_column_text][/vc_tta_section][vc_tta_section title=”What is the outlook for a dog with anal furunculosis?” tab_id=”1534168280911-73cbf72e-73c9″][vc_column_text]Controlling symptoms is a long-term process in many cases. New treatments are being developed, but relapses may occur and permanent treatment can be needed. Anal furunculosis is well known as a difficult and sometimes frustrating disease to treat. Recent treatments have shown encouraging results but euthanasia may need to be considered if your dog is very seriously affected or if your dog’s temperament makes home treatment difficult. More than most diseases, this one calls for a high level of commitment and extreme vigilance on the part of owners. Bear in mind that long-term treatment can prove expensive.[/vc_column_text][/vc_tta_section][vc_tta_section title=”Conclusion” tab_id=”1534168299178-da764af7-463b”][vc_column_text]Whilst anal furunculosis can be a frustrating and difficult condition to treat it is important to seek help as soon as possible. If the condition becomes widespread it can be impossible to control. As there are a number of different treatment options it is important to discuss your dog’s problem with your own vet so that you can work out the most appropriate course of action for you and your pet.[/vc_column_text][/vc_tta_section][/vc_tta_accordion][/vc_column][/vc_row][/vc_section]