https://www.barkandwhiskers.com/2015-08-23-nl-encephalitis/
https://www.barkandwhiskers.com/p/dec46144-4748-49ba-9fb0-9cd006959180/
By Dr. Becker
Encephalitis refers to inflammation of the brain. “Encephalo” means brain and “itis” means inflammation. The brain and spinal cord constitute the central nervous system (CNS), and inflammatory diseases of the CNS are one of the most common causes of neurological disease in animals.
There may also be inflammation of the spinal cord, called myelitis, and/or meningitis, which is inflammation of the membranes that cover the brain and spinal cord, as well as encephalitis.
Certain dog breeds are predisposed to encephalitis, including the German Shorthaired Pointer, Maltese and Yorkshire Terrier.
Causes of encephalitis
There are two main types of encephalitis: infectious and idiopathic. The infectious form of the disease can be caused by bacterial, viral or fungal infection, parasites, immune disorders, tick-borne diseaseand foreign bodies.
We diagnose idiopathic encephalitis when we cannot find an infectious cause for the disease.
Where an animal lives often plays a role in the cause of encephalitis. In areas of the United States where ticks are a problem, tick-borne infections, such as Rocky Mountain spotted fever, Ehrlichia, and Lyme disease, are common causes. In the southwestern United States, a fungal infection known as valley fever can also be a cause.
Bacterial infections causing encephalitis are relatively rare in pets, but they do occur from time to time. Viral causes include distemper and feline infectious peritonitis. When a parasite is involved, Toxoplasma gondii is often the culprit.
Idiopathic encephalitis
When no infectious cause of the disease can be found, idiopathic encephalitis often has an underlying immune-mediated cause, meaning the animal’s immune system attacks its own brain or spinal cord.
Types of immune-mediated diseases seen in dogs with encephalitis include granulomatous meningoencephalitis (GME), which is seen most often in middle-aged small breed dogs.
Another is necrotizing meningoencephalitis (NME). Predisposed breeds include young to middle-aged Pugs, Maltese, Chihuahuas, Papillons, Shih Tzus and Boston Terriers.
A third type of immune disorder that can cause encephalitis is called necrotizing leukoencephalitis (NLE), which most commonly affects Yorkies, Chihuahuas, and Shih Tzus.
Symptoms of encephalitis
The clinical signs of encephalitis depend on the area of the brain affected. Symptoms usually appear suddenly and progress quickly.
If the forebrain is involved, there may be seizures, blindness, behavioral changes, depression, and circling. With brainstem disease, there may be loss of coordination, head tilt, tremors, and facial paralysis. Other signs may include fever, decreased responsiveness, uneven pupil size, or smaller sized “point” pupils.
A dog or cat with encephalitis may have neurological abnormalities originating from a single or focal area of the brain, or from multiple (multifocal) areas of the brain. However, while many other illnesses such as stroke or brain tumor can cause focal neurological signs, when symptoms are multifocal, encephalitis is most often the cause.
Diagnosing encephalitis
While it is important for your veterinarian to perform the usual diagnostic tests on your pet, including blood tests, urine tests, chest x-rays, etc., it is possible that pets with encephalitis may not exhibit no abnormalities during these tests because this is happening in the central nervous system. The system can be completely separated from the rest of the body.
This is why a definitive diagnosis of the disease often involves a lumbar puncture. The cerebrospinal fluid that surrounds the brain and spinal cord speaks directly to what is happening inside the central nervous system. A significant increase in the number of white blood cells in the spinal fluid usually indicates encephalitis.
A lumbar puncture carries certain risks for some animals. Your pet may need a magnetic resonance imaging (MRI) or computed tomography (CT) scan of the brain before a lumbar puncture to look for signs of elevated intracranial pressure that may increase the risk of the procedure. Brain imaging may also be helpful in ruling out other causes of neurological disease such as a brain tumor.
Treatment options
Treatment for encephalitis aims to reduce the severity of the symptoms your pet experiences.
Typically, antibiotics or antifungals will be given if there is an infection. If the pet is having seizures, anticonvulsant medications may be recommended. Low-dose corticosteroid therapy may also be initiated to treat significant cerebrospinal fluid inflammation or serious clinical signs.
Traditional treatments for immune-mediated encephalitis typically involve intentionally suppressing the immune system with high doses of medications for three to six months, and sometimes longer.
Many holistic veterinarians, including myself, have found that integrating complementary therapies such as homotoxicology, ozone therapyand traditional Chinese herbal protocols that address “heat” and “wind” (the diagnosis of encephalitis in traditional Chinese veterinary medicine) have been very beneficial in reducing symptoms and shortening the course of the disease in many patients.
I firmly believe that any animals that have recovered from idiopathic or immune-mediated encephalitis should never be vaccinated again for whatever reason. These animals should undergo antibody titer testing in place of traditional vaccines.
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