It happened so fast. It started as lameness in both front and rear left legs, leaning to the right when walking which progressed to falling over onto her side, head tilt, and blindness. Eight days after the onset of symptoms, she passed in my arms. She was only 11 months old.
Granulomatous Meningoencephalitis (GME) is a disease that suddenly strikes without warning. While the disease itself does not happen often, it has been seen often enough in Chihuahuas to add them to the list of breeds most susceptible.
What Is Granulomatous Meningoencephalitis (GME)?
Encephalitis is an inflammation and swelling of the CNS (central nervous system), while meningitis is an inflammation of the membrane surrounding the brain and the spinal cord. Both diseases are often seen simultaneously. Because of protective barriers to the central nervous system, both meningitis and encephalitis are seen less often than diseases to other organs of the body.
There are three types of Granulomatous Meningoencephalitis:
- Focal is limited to one location in the nervous system
- Disseminated or Multifocal involves many locations in the nervous system and is the most common
- Ocular involves the optic nerves
It is not uncommon to see more than one type present in the same dog.
What causes encephalitis? Encephalitis is considered to be non-infectious and is thought to have an immune-mediated cause. It is sometimes caused by an abnormal response to an infectious agent such as bacteria, parasites, fungi, and tick-transmitted disease. The most common cause is thought to be an overactive immune system. When this happens, the immune system attacks the brain and/or the brain coverings (meninges). This is called idiopathic encephalitis.
Most cases of Granulomatous Meningoencephalitis occur in Toy and small breed dogs, usually in bitches. The average age for onset is in young to middle-aged dogs, ranging from 6 months to 10 years.
Granulomatous Meningoencephalitis – Symptoms
At the onset, symptoms shown will depend on which part of the brain is affected.
Disseminated is the most common type of encephalitis and its symptoms include seizures, walking in circles, lack of balance, stumbling, head tilt, tremors, pain, changes in behavior, and blindness. Symptoms usually start with one or two and quickly worsen or expand to include more symptoms.
Focal symptoms will depend on the area of the brain where the lesions appear, while Ocular symptoms will include sight problems and blindness. The Focal type generally has a slower onset, while Disseminated has a more rapid onset.
Ocular usually shows up as sudden, and generally permanent, blindness in one or both eyes.
Often when a dog is presented, first thoughts can be a bad disc or pinched nerve as well as a possible brain tumor (depending on the symptoms presented at the time), especially to vets who may not have experience with Granulomatous Meningoencephalitis. If the neurologic abnormalities are focal, other causes such as stroke and brain tumor must be ruled out.
The only TRUE way to diagnose is with an MRI or spinal tap. The MRI will not only diagnose GME but will rule out other possibilities as well as let the vet know if a spinal tap is even possible for the individual.
Spinal taps are only performed when all other options have been exhausted. Patients with brain swelling or a tumor have a higher risk of complications from spinal taps. If intracranial pressure is elevated, the removal of any spinal fluid could cause a suction effect and cause a brain herniation. A significant increase in white blood cells in the spinal fluid usually indicates encephalitis.
Unfortunately for most owners, an MRI and/or spinal tap is not possible due to cost and/or location. Routine blood work, urinalysis, and a physical exam are usually performed along with an ultrasound to rule out other possible infections and to help determine which medications can be used. Encephalitis is a very serious condition.
Unfortunately, there is NO cure. Prognosis for permanent recovery is guarded. Shortest survival rates are usually seen in dogs with disseminated and ocular forms of GME. Longer survival rates of three to six months are usually associated with a focal lesion.
Temporary improvements are suspected to be a result of reduction of mast cell function. Continued therapy is required, with improvement for several days to months seen. However, most dogs will eventually succumb to the disease.
Treatment for idiopathic encephalitis will usually involve suppressing the immune system. High doses of steroids such as prednisone are the usual course of action. Antibiotics are prescribed as well, many times, along with pain medication if the patient presents with pain.
If no progress is seen with prednisone alone, more potent immune suppressing medications may be added. Most of these medications are types of chemotherapy and will require periodic blood tests to avoid toxicity. These other drugs may also be used with animals that may be susceptible to the side effects associated with long-term use of prednisone.
Some dogs will respond for a time but later have relapses, causing the use of medication for extended periods of time. Other dogs do not respond to medication at all and pass away quickly. ANY neurological symptoms will require immediate veterinary intervention if hope of survival is expected.
The problem with this disease is that by the time the dog is presented to a vet (especially one who may not recognize the disease on first presentation) it is usually too late to save the dog. Many vets may suspect GME, but by the time the tests are done it is too late to save the dog. Granulomatous Meningoencephalitis is a very fast-moving and, most times, deadly disease. I cannot stress enough that time is of the essence and ANY delay in vet care can cost the life of your dog.
For the Love of Gabby
This article has been written with love and in remembrance of my Dear Sweet Gabby. Her death inspired me to research something not commonly heard about, yet according to many vets, appears to be a problem within the breed.
While doing this research over the course of two months, I have found six cases of GME, or suspected GME, in our immediate Chihuahua community. Of the six, two survived. One recovered completely while the other still has a slight head tilt and is blind in one eye. The other four survived from eight days to several months before passing. One of these improved greatly, but later had a relapse and passed. This does not include the Chihuahuas in the clinical experiences of veterinarians whom I have either spoken to or who have written articles about GME. If a dog presents with ANY neurological symptoms, immediate veterinary care is needed if any hope of survival is expected.
If even one dog can be helped with this information, Gabby’s death has meant something.