Encephalitis
The definition of encephalitis is inflammation of the brain. It occurs in both dogs and cats and is not common.
The causes of encephalitis can be placed into 2 categories: infection or immune-mediated (patient’s own immune system causes the inflammation). In the cases of infection, several agents are possible, such as: distemper virus, rabies virus, fungal diseases, tick-borne diseases, bacteria, protozoa, feline infectious peritonitis, or FIV. When these agents are proven not to be the cause, it can be assumed the patient’s own immune system is causing inflammation in the brain. The reason the body does this is unknown. The breeds predisposed to have immune-mediated encephalitis are Maltese, pugs, Yorkshire terriers, and miniature poodles.
The signs are usually abrupt and progressive. Fever, vomiting, and diarrhea can be the first signs, then the patient will start to show neurological signs. Circling, pacing, head tilt, seizures, incoordination, and nystagmus are all common signs seen.
Treatment will be geared toward the cause. A spinal tap is needed to help determine what is causing the inflammation. Bacterial, fungal, protozoal, and tick-borne diseases all have specific medication that can used. The prognosis depends on how early the disease is caught and how aggressive the treatment is. Viral encephalitis has no treatment, so palliative care is the only option. Prednisone can be used to slow the patient’s immune system and shut off the inflammation. These pets need to be on medication for at least 6 months and may require treatment again in the future during relapses. Many of these pets have a poor prognosis and euthanasia may need to be discussed with your veterinarian.
