Dog Owner's Home Veterinary Handbook.pdf - Mr. Walnuts

Bleeding from the anal canal is recognized by finding blood on the outside
of the stool rather than mixed in with it.
Scooting is rubbing the bottom along the ground. It indicates anal itching.
Anal itching can be caused by flea bites, inflammation of the anal skin, anal
sac disease, or tapeworms.
ANORECTAL OBSTRUCTIONS
A common cause of an anorectal obstruction is an enlarged prostate that
bulges backward and compresses the rectum. This occurs in older male dogs.
Foreign bodies that pass through the upper GI tract may obstruct the rectum.
Pelvic fractures that have healed improperly can narrow the rectum, causing a
blockage. Boston Terriers and Bulldogs are predisposed to this, and any dog
born with a screw tail may have a rigid extension of the tail that pushes down
upon the anal canal, pinching it against the pelvic floor. Other causes of
blockage are fecal impactions, matted stool around the anus, rectal strictures,
perianal gland tumors, perineal hernias, and rectal polyps and cancers.
Rectal strictures result from perianal infections, fistulas, and surgical
attempts to treat them. Perineal hernias are bulges that occur alongside the
anus. They weaken the muscular support of the rectum and interfere with the
mechanics of elimination. The bulge becomes larger as the dog strains.
Perineal hernias primarily occur in elderly, unneutered males.
The principal sign of anorectal obstruction is straining to defecate. The
stool may be flat or ribbonlike. The dog may or may not pass blood. The diagnosis
is made by digital rectal examination and, occasionally, by colonoscopy.
Treatment: It varies with the cause of the obstruction. Most foreign bodies
can be removed by digital extraction under sedation or anesthesia. Neutering
is the treatment of choice for an enlarged prostate (see page 418). Perineal
hernias are repaired with a surgical procedure plus neutering, or by neutering
alone. Strictures are corrected with surgery. Perianal gland tumors and polyps
are discussed later in this chapter (page 293). Constipation associated with
the screw tail usually requires surgical correction of the tail.
For conditions for which surgical treatment is not feasible, the goal is to
maintain normal defecation using laxatives and stool-softening diets (see
Constipation, page 280).
PSEUDOCONSTIPATION (MATTED STOOL AROUND THE ANUS)
THE DIGESTIVE SYSTEM • 287
When hair around the anus becomes densely matted with dried stool and forms
a barrier to defecation, pseudoconstipation results. It occurs in longhaired dogs,
usually following a bout of diarrhea. The skin becomes irritated, painful, and
infected. This introduces an element of voluntary retention, as well.