Excerpt from Ask the Vet by Dr. Shawn Ashley in Pug Talk Magazine (Sept/Oct/92)
The true function of anal glands in the 21st century house dog and cat is not well known. Scent marking and territorial boundary setting has been the most acceptable theory.
The anal glands are paired sacs located at four and eight o'clock positions around the rectum. They are comprised of sebaceous oil glands that secrete a serous odoriferous brown discharge.
The discharge is usually expressed as feces are eliminated. However, in smaller breed dogs this discharge seems to be saved until times of extreme fear, anger, or revenge! in these breeds the anal glands are usually expressed as the groomer lifts the tail and manually pushes up and out.
Anal sacs are very prone to an array of problems, from impactions, abscessation, and tumours. Anal sac problems often go unnoticed -until the dog begins to scoot or drag its rear end on the floor usually in front of reputable guests.
It is felt that anal sac impaction in the adult animal may be influenced by the socially restrictive environments of inside dogs; ie. sedentary lifestyles, obesity, seborrheic (oily, infected) skin conditions, poor muscle tone, and abnormal bowel elimination/retention.
Intestinal parasites, especially tapeworms, in younger dogs have been implicated in anal gland impactions, as well. As the glands fill the discharge becomes thickened and pasty, the dog continues to scoot, lick and chew which leads to discomfort and eventually infection.
If the infected gland is not emptied the gland becomes abscessed often described by owners as a hemorrhoidal mass. If the pressure is not released the dog becomes a tyrant due to the pain and the gland soon ruptures.
These series of events will continue over and over if the gland is not properly lanced, expressed, flushed, and the anal sac's duct is evaluated for patency. If due to chronic irritation, strictures of scar tissues, or tumour growth the anal sac cannot drain through the duct, surgical excision is the treatment of choice.
Anal sacculectomy of anal sac removal should not be performed until the infection and inflammation have been resolved by medical management. Once the surrounding skin integrity is improved the anal sac and duct are totally excised.
If the animal is kept from the incision and it is kept clean the incision heals completely without complication.
Post operative complications arise primarily from self-trauma and factors leading to poor skin healing ability -- old age produces lowered immunity and skin protective mechanisms; oily chronic infected skin conditions, allergic dermatitis, poor nutrition, debilitating disease, and obesity are a few examples of the factors that influence wound healing.
Further complications revolve around cases where out of control infections or tumours have been allowed to grow.
In these cases damage to the external anal sphincter or incomplete removal of the anal sac may occur.
This leads to fecal incontinence and chronic draining tracts, respectively. Depending on the severity of the abscessed anal gland the surgical procedure can be long and tedious; therefore, pre-operative blood work and a complete physical are of the utmost importance.
The best medicine is prevention by controlling skin infections, allergies, FLEAS, intestinal worms, and expressing the anal glands regularly (the frequency depends on the individual dog ranging on average from 4 - 16 weeks).
If the discharge becomes thickened and/or the gland is hard to express a trip to the veterinarian is in order so the anal duct and sac can be flushed and impaction avoided.
Finally, if you find yourself expressing often seek help to insure you are properly 'squeezing' and seek out any factors that may be contributing to the problem - - low residue diets such as prescription i/d or w/d may help, as well.