Brain Diseases in Dogs
Encephalitis (Brain Infection) continued...
The diagnosis of encephalitis or meningitis is based on analysis of
cerebrospinal fluid obtained by spinal tap. Serologic tests may identify the
cause of the inflammation.
Treatment: Corticosteroids are used to reduce inflammation and swelling of
the brain. Seizures are controlled with anticonvulsants. Antibiotics are used to treat bacterial infections.
Rickettsia are extremely sensitive to tetracycline and doxycycline. Dogs who
recover from encephalitis may develop seizure disorders and other neurological
symptoms. Rabies is almost always fatal.
This common inflammatory brain disease in dogs is abbreviated GME. The cause
is unknown. Female dogs of small breeds, especially terriers, Dachshunds,
Poodles, and Poodle crosses, are predisposed. Although GME can occur at any
age, most affected dogs are 2 to 6 years of age.
A chronic form of GME called Pug encephalitis occurs as an inherited disease
in Pugs between the ages of 9 months and 4 years. It often begins with
seizures, confusion, and loss of memory. This form of the disease has also been
seen in Yorkshire Terriers and Maltese.
GME can affect all parts of the brain (the disseminated form), or only
specific areas (the focal form). There is a rare ocular form that targets the
optic nerves of the eyes.
The disseminated disease appears suddenly and progresses over a matter of
weeks. It is characterized by incoordination, stumbling, falling, circling,
head tilt, seizures and, dementia.
The focal disease begins with symptoms such as those of a brain tumor. Behavior and
personality changes may predominate. The focal disease progresses to the
disseminated disease over a period of 3 to 6 months.
The ocular disease is characterized by sudden blindness with a dilated pupil. It progresses to the
disseminated disease more slowly than does the focal disease.
GME can be suspected when a toy dog such as a Poodle inexplicably develops
confusion, disorientation, seizures, or other neurological signs that progress
rapidly over a matter of weeks. A spinal tap with analysis of cerebrospinal
fluid helps confirm the diagnosis. A CAT scan or MRI is useful in determining
the form and location of the disease.
Treatment: Corticosteroids and immunosuppressive drugs may slow the
progression of GME and provide temporary relief for several months. However,
GME is almost invariably a progressive and fatal disease.