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

362 •DOG OWNER’S HOME VETERINARY HANDBOOK
that can metastasize to the brain include cancers of the mammary glands,
prostate, and lungs, as well as hemangiosarcoma.
Symptoms depend on the tumor’s location and rate of growth. Tumors in
the cerebrum produce seizures and/or behavioral changes. The dog may
exhibit a staggering gait, head tilt, nystagmus (rhythmic movement of the
eyeballs), and limb weakness or paralysis. These signs are progressive and continue
to worsen. Late signs are stupor and coma.
A brain abscess is a collection of pus in or around the brain. The signs are
similar to those of a brain tumor. These dogs will often have a fever. There
may be a prior infection in the oral cavity, inner ear, or respiratory tract.
Treatment: The diagnosis of tumor or abscess is made by neurological
examination and special tests, including EEG, cerebrospinal fluid analysis,
and CAT scan or MRI. Surgical removal of benign brain tumors may be possible
in some cases. Chemotherapy and radiation therapy have not proven to be
effective against most brain tumors in dogs. There may be temporary improvement
with corticosteroids and anticonvulsants.
Abscesses are treated with high doses of antibiotics. Corticosteroids are
usually contraindicated. The outlook for recovery is guarded.
STROKE
Strokes are not common in dogs. A stroke can be caused by bleeding into the
brain, obstruction of an artery caused by an embolus, or clotting of a cerebral
artery. An embolus is a clot that develops at another site and travels through
the vascular system to a smaller vessel, where it becomes lodged and interrupts
blood flow to the area served by that artery. This results in death of tissue
in the affected area, a condition called infarction. Most strokes in dogs are
caused by emboli.
Bleeding in the brain is seen with ruptured cerebral blood vessels and brain
tumors. Spontaneous bleeding may occur with coagulation disorders.
Disseminated intravascular coagulation is a cause of both bleeding and infarction.
Some hemorrhagic strokes occur for unknown reasons.
Infarctions can occur with Rocky Mountain spotted fever, hardening of the
arteries associated with hypothyroidism, and for unknown reasons.
The onset of stroke is sudden. The signs depend on the location and extent
of the bleeding or brain infarction. They include behavioral changes, disorientation,
seizures, weakness or paralysis on one side of the body, stupor, and
coma. Large strokes are often accompanied by cardiac arrhythmias and collapse.
The diagnostic workup is similar to that for a brain tumor.
Treatment: Treatment involves the use of corticosteroids to prevent brain
swelling and anticonvulsants to control seizures. Dogs who survive the first
few days have a good prognosis for recovery. The long-term outlook depends
on controlling or eliminating the underlying disease.