Necrotizing Encephalitis (NME) in Dogs
What is necrotizing encephalitis?
The disease in dogs often referred to as NME (Necrotizing Meningoencephalitis). NME is an inflammatory disease in certain breeds of dog that leads to necrosis (cell death) of the cerebrum. NME is a genetic disease, where acute necrotizing encephalitis may be infectious (viral, bacterial), auto-immune or fungal (GME- granulomatous meningoencephalitis).
What causes necrotizing encephalitis in dogs?
NME is considered a genetic disease and is seen in specific breeds Pugs are the most common breed affected, and 1.2% of pugs will die from NME or Pug Dog Encephalitis as it’s commonly called. The exact pathogenesis is unknown at this point. It is likely due to an immune-mediated familial process. Recently there is evidence that there is an association with the dog leukocyte antigen (DLA) region of dog chromosome 12.
Which dog breeds are most likely to get necrotizing encephalitis?
The most common breed affected is the Pug and even more so the female. The other less commonly affected breeds are: Maltese, Yorkshire terrier, Chihuahua, French bulldog, Papillion, Pekingese and Shih Tzu. The common age is a young adult from 6 months – 7 years of age.
What signs and symptoms would suggest that a dog might have necrotizing encephalitis?
The common presenting signs of NME are neurologic in origin. These may include:
Other more general signs of lethargy, decreased appetite, vomiting, diarrhea and depression may also be seen. The progression of signs may be rapid over hours to days. It may also be a slower onset over years, although this is the less common presentation.
How is necrotizing encephalitis diagnosed?
The only way to definitively diagnose NME is by getting histopathology (biopsy) of the brain. This is done post-mortem. While the patient is still alive, we diagnose it based on the progressive neurologic signs, breed, age and spinal fluid analysis. A CSF (cerebral spinal fluid) tap can be done to show an elevated total protein and monocytes will point toward the diagnosis. An MRI can be done to show loss of distinction between white and gray matter, cystic structures in the brain and an overall bright appearance to the meninges.
A genetic susceptibility test now exists through the UC Davis Veterinary Genetic Laboratory. It does not test for Pug Dog Encephalitis specifically, but it tells whether a certain individual is more susceptible to developing the disease based on genetic markers. It is recommended to have this test done in dogs selected for breeding.
If an owner suspects necrotizing encephalitis, when would be the right time to consult an Expert or a Vet?
If neurologic signs (seizures, tremors, acute blindness, circling) are noticed, the dog should be evaluated by a veterinarian as soon as possible. If more mild signs of lethargy or GI upset are seen, that is something that may be monitored and addressed more conservatively.
How is necrotizing encephalitis treated? Are there any home remedies?
At this time, we do not have any effective treatment for NME. It carries a poor prognosis, and most dogs will die from the disease fairly soon after the diagnosis. We treat symptomatically to decrease the inflammatory and immune response by using steroids (Prednisone). We manage seizures with anti-seizure medications (Phenobarbital, Zonisamide, Levetiracetam). There are no home remedies that have any proven efficacy at this time.
How much can necrotizing encephalitis treatment cost?
The treatment is relatively inexpensive when it comes to steroids and anti-seizure medications. The costliest part of NME is the work up. It can cost $100-200 in bloodwork and $1,500-$2,500 if an MRI and CSF tap are pursued. These are done through a specialty hospital and with a boarded veterinary neurologist.
What is the prognosis for a dog with necrotizing encephalitis?
Sadly, the prognosis is poor for NME. It is a disease that is uncommon, and very hard on the patient, owner, and veterinarian. These are typically normal healthy young dogs that all of the sudden deteriorate rapidly. Rarely we’ll see one that we can manage for a year or more, but more commonly they succumb to the disease or are euthanized within days to weeks of the signs presenting.
About the Author:
Dr Gary Ryder has been an Expert on JustAnswer since January 2009 with over 14,900 satisfied customers.
Dr. Gary Ryder, DMV grew up in Howell, Michigan and attended Michigan State University where he received a BS in Physiology in 2003. He went on to attend Ross University School of Veterinary Medicine in St Kitts, and completed his clinical education at the University of Wisconsin-Madison in 2007 and has practiced emergency medicine ever since. Dr. Ryder has practiced at Southwest Michigan Animal Emergency Hospital in Kalamazoo, Michigan, since 2008.
He has a special interest in emergency surgery, pain management, shock therapy and internal medicine cases. He is also a member of the VECCS (Veterinary Emergency and Critical Care Society) and an elected officer in our local SWMVMA (Southwest Michigan Veterinary Medical Association). Dr. Ryder and his wife Alisha and their son Zayden, reside in Texas Corners, with their family pets, Mac (rescue dog) and Megatron (cat). In his spare time, he loves to play hockey and golf.