Granulocytic Meningoencephalitis in Dogsby Deborah Lundin
No dog owner wants to hear that her dog has a progressive brain disease, but unfortunately, that is exactly what granulocytic meningoencephalitis is. Also known as GME, inflammatory reticulosis, granulomatous reticulosis, hestiocytic encephalitis and neoplastic reticulosis, granulocytic meningoencephalitis targets the meninges, or lining of the brain and spinal cord. Immune cells disrupt the blood vessels in this area, often forming masses or nodules. Symptoms vary depending on which area of the central nervous system is involved. Regardless of the area, the prognosis is not good for dogs diagnosed with this condition.
What Causes Granulocytic Meningoencephalitis
The direct cause of granulocytic meningoencephalitis is unknown. According to veterinarian Dr. John McDonnell of PetPlace.com, cases have shown possible connections to infectious agents, immune system abnormalities or neoplastic causes. In some cases, granulocytic meningoencephalitis may be a precursor to cancer.
The Type Depends on the Area Infected
GME is broken down into three different types -- focal, disseminated and ophthalmic -- depending on the location of inflammation. Disseminated is the most common form and affects multiple areas in the central nervous system. Focal GME affects one area, such as the brain. Ophthalmic GME affects the eye and optic nerve. Symptoms will vary based on the type of disease.
Symptoms Present with Granulocytic Meningoencephalitis
Because disseminated GME affects multiple areas, symptoms can be widespread and include seizures, neck or spine pain, mobility problems, blindness and weakness. Unfortunately, disseminated GME progresses rapidly and, according to Mar Vista Animal Medical Center, many dogs do not survive more than a week or so after diagnosis. Focal GME affects only one area, so symptoms depend on the area affected. Ophthalmic GME can cause sudden and permanent blindness.
Diagnosing Granulocytic Meningoencephalitis
Unfortunately, the main way to diagnose GME is through tissue biopsy through brain surgery, which is not practical. An MRI is an expensive test, but it is the second best way to confirm GME. Your veterinarian may also do a spinal tap to rule out other possible conditions, such as viral, parasitic or fungal encephalitis.
Treating the Disease and Improving Quality of Life
Because the cause of GME is unknown, treatment focuses on reducing the inflammation and improving your dog’s quality of life. Corticosteroids, such as prednisone, help reduce inflammation and decrease symptoms. Once symptoms reduce, your veterinarian may be able to reduce the steroid dosage, but chances are your dog will require medication for the rest of his life. If the disease causes seizures, anti-seizure medications may also be prescribed. In cases of focal GME, radiotherapy may help reduce symptoms.
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