Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Don't Ignore Your Pet's Pain in the Butt!

Pet Column for the week of January 25, 1999

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
By Sarah Probst
Information Specialist

"Behavioral changes in your pet such as scooting, tail chasing, and excessive licking or biting
around the tail and anus are signs that your cat or dog might have a problem with its anal
sacs and should be examined by a veterinarian promptly," says Dr. David Barber,
veterinarian formerly with the University of Illinois College of Veterinary Medicine in Urbana. With
more than 14 years of experience in anal sacculectomy-anal sac removal surgery-Dr.
Barber jokes that he is known for being gifted in the glamorous job of expressing and
surgically removing anal sacs

"Anal sacs are structures similar to those used by skunks when they spray. These structures
are present but less well developed in cats and dogs," explains Dr. Barber. Dogs and cats
lack voluntary control of the sacs. Normally, the semi-liquid, fetid material is squeezed out
passively when pets defecate, but sometimes things go wrong.

Problems associated with anal sacs include impaction, infection, abscess, and neoplasia.
Impaction occurs when the duct or tube through which an anal sac empties becomes
clogged. Pressure builds in the sac and on surrounding tissue, resulting in painful defecation
and, in some cases, constipation.

Bacterial infections cause damage and inflammation resulting in pain and itchiness. This
condition, which Dr. Barber speculates must be far more painful than hemorrhoids,
sometimes leads to unusual levels of fear or aggression in pets. Left untreated, infections can

"The development of an abscess involves the walling off of the infected area with a fibrous
capsule as the body seeks to defend itself," explains Dr. Barber. "Pain associated with
abscesses can become very intense as pressure and inflammation increase." If this stage of
the disease is left untreated, the abscess could rupture and drain through the skin,
temporarily reducing pain, until the body seals the rupture, causing the process to start over
again. "If the abscess drains into the deeper surrounding tissue, there can be severe
consequences," adds Dr. Barber.

A neoplasm in the anal sac-more common among dachshunds, cocker spaniels, German
shepherds, beagles, English bulldogs, and Samoyeds-is an abnormal growth or tumor.
Some of these growths are benign and others are very aggressive cancers. The location of
the anal sac makes even a benign growth a problem because it impinges on the surrounding

"Many impacted anal sacs and some infected anal sacs can be successfully treated by
"expressing" them-emptying the sacs by means of careful massage of the sacs," explains Dr.
Barber. "Diseased sacs may be very painful and may require some level of pain relief
medication and perhaps a tranquilizer or sedative to keep the treatment from being a bad
experience for the pet." In addition, your veterinarian may use a lavage to wash out the anal

For some dogs and even some cats, anal sac disease becomes a severe, repeated, and
persistent experience. "In these cases, the most humane, efficient, and cost-effective
treatment choice is surgical removal of the anal sacs-anal sacculectomy," suggests Dr.
Barber. It is recommended that both sacs be removed at the time of the surgery.

"Anal sacs have no known beneficial purpose for dogs and cats. I often compare the anal
sacs to the appendix in humans. As long as it is healthy, we leave it alone even though we
don't need it. If severe or repeated problems develop, we may be better off without it,"
says Dr. Barber.

For more information, contact your local veterinarian.