Anal Sac Disease in Cats
Dr. Cathy Reese
Veterinary care should include diagnostic tests and subsequent treatment recommendations. History: Your veterinarian will ask specific questions regarding defecation habits (straining, size/shape of stool, frequency, pain), appetite, weight loss, drinking and urination habits, what symptoms (licking, "scooting") you have noticed and how long they have been going on.
Diagnostic tests that your veterinarian may wish to perform include:
Physical exam: Your veterinarian will perform a complete physical exam, including a rectal exam of the anal sacs. The veterinarian will attempt to express the anal sacs and note the quality of the secretions.
Blood tests: If your veterinarian suspects an infection or abscess of the anal sacs, he or she may recommend a complete blood count, which will assess the number and type of red and white blood cells and platelets. The white blood cell count will usually increase in an infection. If your veterinarian suspects an anal sac tumor, he or she may recommend a serum chemistry panel. This test checks the major organs to see if they are functioning normally (important if the patient will need anesthesia) and also checks the levels of the major electrolytes in the body. Anal sac tumors can cause an increase in serum calcium levels.
Chest and abdominal X-rays: Anal sac tumors can spread to lymph nodes and lungs, and rarely to other organs or bones of the body. X-rays are used to check for obvious spread of the cancer, although microscopic spread cannot be ruled out. Chest X-rays are also important in older patients that will be undergoing anesthesia, to make sure that there is no heart or lung disease that would make anesthesia risky.
Abdominal ultrasound: The most common location for anal sac tumors to spread is the sublumbar lymph nodes. These lymph nodes can become extremely large, and may be able to be palpated rectally. If not, they can be seen using an ultrasound. If the lymph nodes become very large, they can push on the colon and obstruct flow of feces. This can make defecation difficult and may alter the shape or size of the stool.
Anal sac expression: The veterinarian rectally palpates the anal sacs and squeezes them to empty the sacs of the secretions. If the patient is too painful or if the secretions are too firm, then the patient may need to be heavily sedated or anesthetized to have this procedure done. Anal sac expression is often all that needs to be done for simple cases of anal sac impaction or mild cases of anal sacculitis.
Anal sac irrigation: This involves anesthetizing the patient and flushing saline into the opening of the anal sac to break up firm anal sac secretions so that the sacs can be emptied. This procedure is indicated when the anal sacs cannot be manually expressed. More severe cases of anal sacculitis often require subsequent irrigation with a topical steroid to help decrease the inflammation.
Abscess lancing: An anal sac abscess, unless it has already ruptured on its own, needs to be opened up, or "lanced" and drained. The cat may need to be briefly anesthetized and the abscess is opened up and flushed with saline. Antibiotics are indicated to treat the underlying infection. Warm compresses applied to the area are also helpful.
Anal sacculectomy: This is the technical term for surgical removal of the anal sac. This can be done to one or both sides. It is often recommended for recurrent cases of anal sac infection or anal sac impaction, and is necessary for treatment of anal sac tumors. The possible risks of surgery, besides the risks of general anesthesia, are fecal incontinence, chronic draining tracts from residual infection or secretory tissue, recurrence of the tumor, and straining to defecate from postoperative anal scar formation.
Sublumbar lymph node removal: If a tumor of the anal sac has spread to the sublumbar lymph nodes, then removal of the lymph nodes can be considered. This is a technically challenging procedure that can result in significant bleeding during surgery and could also result in temporary or permanent urinary incontinence since the nerves controlling urination are close to the lymph nodes. It is not curative, however it may alleviate some of the problems associated with the enlarged lymph nodes, such as difficulty defecating.
Chemotherapy and radiation therapy: Both of these treatment types have been used with mixed results. There is unfortunately no cure for this disease, but adding these therapies to surgical removal of the tumors can help prolong the cat's life.