Trigeminal Neuritis in Dogs: Dropped Jaw Symptoms, Treatment

Trigeminal neuritis in dogs (i.e. dropped jaw in dogs) affects a dog’s ability to use the jaw muscles to close the mouth. Integrative veterinarian Dr. Julie Buzby explains the signs, diagnosis, treatment, and prognosis to help clear up some of the mystery surrounding this disease.

Some conditions in dogs have subtle symptoms, but trigeminal neuritis is not one of them. The signs come on suddenly and are quite dramatic. Dogs who develop trigeminal neuritis—also called trigeminal neuropathy, trigeminal neuralgia, or dropped jaw in dogs—cannot close their mouths.

Seeing your dog’s mouth hanging open can make your jaw drop in surprise. But as you will soon discover, the outlook for dogs with trigeminal neuritis isn’t nearly as dire at it may seem.

What is trigeminal neuritis in dogs?

Trigeminal neuritis in dogs is a condition where the trigeminal nerve, which controls the jaw muscles, becomes inflamed, leading to the dog being unable to move his or her jaw. As a result, the dog’s mouth hangs open. This explains why trigeminal neuritis is also called dropped jaw.

Overall, trigeminal neuritis is the most common neurological cause of paralysis of the jaw in dogs.

To understand trigeminal neuropathy, we must take a look at the trigeminal nerve itself. There are 12 paired cranial nerves that provide motor and sensory functions for the head and neck. The trigeminal nerve is the fifth cranial nerve (CN V).

There are three branches of the trigeminal nerve. Two provide sensation to the eyes, nose, mouth, and face. And one branch, the one most clearly affected by trigeminal neuritis, provides both facial sensation and motor function to the chewing muscles (i.e. muscles of mastication).

However, in trigeminal neuritis, the trigeminal nerve becomes inflamed, which affects its function. Based on the jobs of the trigeminal nerve, it would only make sense then that trigeminal neuritis impacts a dog’s ability to move his or her jaw (and sometimes feel his or her face).

What causes trigeminal neuritis in dogs?

Trigeminal neuritis is an idiopathic condition that is usually bilateral (i.e. affecting both sides of the face). The word “idiopathic” means we don’t know what causes it. However, some vets believe that it could be immune-mediated or related to a viral infection.

Interestingly, in a study of 29 dogs with trigeminal neuritis, Golden Retrievers were overrepresented. But otherwise, no age, sex, or environmental factors (e.g. season of the year or recent vaccinations) seem to be linked to trigeminal neuritis.

Unfortunately, because we don’t know the underlying cause of idiopathic trigeminal neuropathy, there are not really any good ways to prevent it from happening.

What are the symptoms of trigeminal neuritis in dogs?

As you may infer from the name “dropped jaw,” clinical signs of idiopathic trigeminal neuritis primarily revolve around loss of jaw motor function. However, about 35% of dogs will also have changes to the sensation of their face.

Some of the symptoms of trigeminal neuritis include:

• Inability to close the mouth—This is the most characteristic symptom of trigeminal neuritis and also the most obvious.
• Difficulty eating and drinking due to jaw paralysis—Affected dogs may still have tongue function but cannot pick up and chew food due to lack of jaw function.
• Excessive drooling—The dog may drool more due to not being able to close his or her mouth.
• Decreased facial sensation—While difficult to notice as a dog parent, affected dogs may not be able to feel their nose, eyes, or face as well as normal (or at all).
• Difficulty picking up toys or other objects—Since the jaw muscles don’t work, the dog can’t grasp items with his or her mouth.
• Horner’s syndrome in dogs—About 8% of dogs with trigeminal neuritis will also have signs of Horner’s syndrome including a sunken eye, droopy eyelid, constricted pupil, and elevated third eyelid in one of their eyes.

If you see these symptoms, please make an appointment with your veterinarian.

How is trigeminal neuritis in dogs diagnosed?

Your veterinarian will start with collecting a history and performing a physical and neurologic exam. As part of the history, the vet will want to know if your dog is current on his or her rabies vaccination and if your dog has contact with wildlife. These questions are important because rabies can also cause a dropped jaw in dogs and is transmissible to humans.

Physical and neurologic exam

On the physical examination, the vet will be looking for signs of orthopedic problems that could also cause a dropped jaw. Two examples are a dislocated or broken jaw.

Then the vet will use the neurologic exam to assess your dog’s ability to close the jaw or feel the face. Plus, he or she will look for any other neurologic problems.

This history and examination is important because trigeminal neuritis is a diagnosis of exclusion. That means that there is no specific finding on blood work or imaging that can diagnose it. Therefore, the vet will reach a diagnosis based on ruling out other conditions and taking into account the clinical signs, examination findings, and other clues.

Diagnostic testing to rule out other conditions

As part of ruling out conditions that can cause similar symptoms, the vet may recommend several diagnostic tests. They include blood tests for dogs, urinalysis, and/or imaging such as X-rays, MRI, or CT. These tests can help rule out other diseases like jaw fractures or dislocations, cancer, infections, head trauma, or brain inflammation.

Oral exam under sedation

Your vet may also recommend sedation or anesthesia in order to perform a thorough oral exam on your dog. Even if their jaw muscles are impaired, it can be challenging to do a comprehensive exam of the mouth of awake dogs. Thus, sedation gives the vet a much better chance of getting the information he or she needs.

How is trigeminal neuritis treated in dogs?

Just like there isn’t a diagnostic tests specific for trigeminal neuritis, there also aren’t any ways to directly treat it. Instead, treatment for trigeminal neuritis focuses on supportive care. The most important aspect of supportive treatment for dogs with trigeminal neuralgia is ensuring they receive sufficient nutrition and hydration.

How do you feed a dog with trigeminal neuritis?

If your dog has dropped jaw, it is critically important that you and your veterinarian monitor your dog’s eating and drinking. You need to be very proactive about preventing dehydration and making sure your dog is getting enough calories.

It takes weeks for trigeminal neuritis to resolve. So feeding your dog will be an ongoing project.

Make a gruel

Many dogs with trigeminal neuropathy still have enough tongue function to lap up liquids. This means they can drink water and lap up canned food made into a gruel. This hand feeding process can be pretty messy though!

If your dog is eating this way, it is important to keep a close eye on how much food and water your dog is actually able to swallow. Should you have any concerns about how much your dog is taking in, please consult your vet promptly.

Use a feeding tube

Sometimes dogs may be attempting to eat or drink but not actually getting enough to keep up with their needs. Or they may not be able to eat or swallow well at all. In those cases, the dog may need a feeding tube.

It may sound intimidating, but feeding tubes are minimally invasive, well-tolerated, and very effective tools to temporarily allow us to bypass the mouth to provide nutrition and hydration. Dogs do not have to stay in the hospital the entire time the feeding tube is in place. And it is surprisingly simple to learn how to use a feeding tube at home.

How else can you care for a dog with trigeminal neuritis?

Veterinarians have also tried treating trigeminal neuritis with steroids like prednisone for dogs. But there is not currently evidence to demonstrate that it makes a difference in the course of the disease.

For some dogs, it may be helpful to make a tape muzzle to hold the mouth partially closed while the dog is recovering. And dog parents can carefully open and close the jaw to help decrease muscle loss. Plus, chewing on soft toys (when the dog is able to) can also help ward off muscle loss or stiffness.

Does trigeminal neuralgia go away in dogs?

Fortunately, most dogs fully recover from trigeminal neuritis in about one to two months. Typically within two to three weeks of diagnosis they are able to eat on their own. And on average, dogs recover in three weeks. However, it may take up to 10 weeks for recovery in some dogs. And very rarely, trigeminal nerve function does not return.

Since trigeminal neuritis is self-limiting (i.e. goes away on its own) the prognosis is usually good. As long as you are able to ensure adequate nutrition and hydration, most dogs with drop jaw do very well with just time and supportive care.

Sometimes trigeminal neuritis can reoccur. However, this does not seem to be common.

Hope for dogs with trigeminal neuritis

Although it looks very scary and comes on seemingly out of nowhere, there is a lot of hope for dogs with trigeminal neuritis. This is a situation where the body has amazing ways of healing itself when given time and good nursing care.

So if your dog suddenly loses the ability to close his or her mouth, do not panic! Instead, make an appointment with your vet right away. He or she can guide you through the next steps to give your pup the best support.

While it might be a big time commitment at first to ensure your dog is getting enough food and water, remember that this isn’t forever. Chances are good that in a month or so, trigeminal neuralgia will be resolved and things will be back to normal.

Has your dog had trigeminal neuritis?

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