1. Pathogen free inflammatory brain disease is common in the dog, and rare in the cat. Several distinct diseases are recognized,
some of which appear to preferentially affect the brainstem cerebellum.
A. Granulomatous meningoencephalomyelitis (GME). Typically occurs in young to middle aged small breed dogs, but can be found
in all breeds. Signs may be localized or multifocal/diffuse. Tentative diagnosis is based on inflammatory CSF, advanced imaging
and biopsy. The disease is progressive but may respond to anti-inflammatory or immunomodulatory drugs such as corticosteroids.
Radiotherapy has been advocated in some circumstances. Prognosis is poor in the long term and most animals die in 3-12 months.
A clinical research project is underway at UC Davis as of June 1 2004 studying GME in dogs. Contact Karen Vernau at UCD for
B. Necrotising encephalitis of Yorkshire Terriers. A progressive inflammatory disease predominantly affecting the brainstem.
Definitive diagnosis is by biopsy or at post mortem. Treatment with antiinflammatory drugs has been unsuccessful and prognosis
Vestibular signs may be due to primary damage, or secondary to raised intracranial pressure, herniation or progression of
hemorrhage etc. Serial neurological examinations are essential to monitor progress. CT is the imaging modality of choice in
the 1st 24 hours (for acute hemorrhage and bony involvement). MRI is preferential for imaging the brain after this period.
Treatment depends on the injuries sustained and may include the use of hyperosmolar agents such as mannitol to decrease intracranial
pressure, supportive intensive care and surgery to repair fractures and provide decompression. Prognosis depends on the extent
of brainstem involvement and the underlying cause.
Metronidazole. Doses of metronidazole over 60 mg/kg daily have been associated with acute onset of vestibular signs, often
with a marked vertical nystagmus and ataxia. Other CNS signs such as seizures may be apparent. Diagnosis is based on history
and clinical signs and prognosis is good if the diagnosis is made early and the administration stopped.
Hemorrhage, stroke, infarction are uncommon in domestic species but can occur secondary to hypothyroidism, coagulopathies,
hyperviscosity syndromes, amyloidosis, septicemia and cardiac disease.