Brain and Spinal Cord Inflammation (Polioencephalomyelitis) in Cats

By PetMD Editorial on Oct. 7, 2008

Polioencephalomyelitis in Cats

Polioencephalomyelitis is a non-suppurative meningoencephalomyelitis(non-draining inflammation of the gray matter of the brain and spinal cord). This condition causes nerve degeneration, and demyelination (degeneration of the sheath surrounding the nerve) of the neurons in the thoracic spinal cord (upper back). Lesions can also be seen in the cervical spinal cord (neck), lumbar spinal cord (lower back), brainstem (base of the brain), and the cerebrum (the largest part of the brain).

Symptoms and Types

  • Ataxia: chronic, progressive incoordination of the hind limbs, or of all four limbs
  • Paraparesis: weakness in the lower body
  • Seizures
  • Head tremors



Polioencephalomyelitis is a viral infection, most likely spread through mucus from the nose and mouth. It is suspected to be caused by the Borna virus, an infection of the brain tissue that affects several mammalian populations, but this is unproven. The cause of this disease has a long documented history, but its origin is generally unknown.


Your veterinarian will perform a complete physical exam on your cat, including a chemical blood profile, a complete blood count, a urinalysis, and an electrolyte panel to rule out or confirm other diseases. The doctor may also take a sample of cerebrospinal fluid (CSF) for laboratory cellular analysis.

You will need to provide a thorough history of your pet's health leading up to the onset of symptoms.


Steroid therapy may reduce inflammation and improve clinical signs, at least temporarily.

Living and Management

There is very little known about this disease. Unfortunately, what is known is that it is a progressive disease with a poor prognosis. Most animals with this disease will need to be euthanized, since the symptoms will only worsen.

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