Knowing the signs of a brain tumor in dogs can be helpful whether you want to be a well-informed dog parent, are worried your dog could have a brain tumor, or are wondering what other symptoms your dog with a brain tumor might exhibit. To help dog parents like you, integrative veterinarian Dr. Julie Buzby discusses 16 signs of a brain tumor in dogs.
As our beloved companions age, they experience a variety of physical and mental changes. So sometimes it can be hard to know how significant a particular symptom might be. You could easily find yourself wondering (or Googling), “Is this change normal for an older dog? Or could it be a sign of a brain tumor?”
Ultimately, you need a vet visit to get a definitive answer. But it can be helpful to know the potential symptoms for brain tumors in dogs, and what other conditions those signs could be pointing to.
What is a brain tumor in dogs?
In short, a brain tumor is a mass in the brain or tissues surrounding the brain that develops due to disordered cell growth. There are many different types of brain tumors in dogs. Some are primary brain tumors, which arise from the brain or meninges (i.e. covering of the brain and spinal cord). Others are secondary brain tumors. These masses occur when cancer in a different part of the body ends up spreading to the brain.
Overall, brain tumors tend to occur in older dogs. While there are numerous types of brain tumors, meningioma is the most common primary brain tumor in dogs. And glial tumors are the second most common.
The diagnosis of brain tumors in dogs, treatment options (like radiation therapy or surgery), and prognosis for a dog with a brain tumor are beyond the scope of this article. But you can get the details in my article: Brain Tumor In Dogs: A Dog Parent’s Guide.
In this article, I want to focus on the signs of a brain tumor in dogs. That way you can recognize them at home and/or monitor your dog for changes after the diagnosis of a brain tumor.
4 look-alike conditions
Before discussing dog brain tumor symptoms, it is important to understand that some signs of a brain tumor can also occur fairly commonly in four other neurological conditions—vestibular disease, epilepsy, canine cognitive dysfunction, and stroke.
Vestibular disease
Vestibular disease in dogs, or doggie vertigo, occurs when a dog’s vestibular system (which is responsible for helping your dog maintain balance) is not working properly. It is most common in senior dogs and cats and in dogs who have severe ear infections (i.e. otitis in dogs).
Epilepsy
Epilepsy in dogs is very similar to epilepsy in humans. This disease consists of recurring seizures that don’t have any distinct cause (versus other seizures that occur due to a brain tumor, infection, or other known cause). Epilepsy can affect dogs of any age, but most dogs with epilepsy experience their first seizure between 1-5 years old.
Canine cognitive dysfunction
Canine cognitive dysfunction (aka CCD or doggy dementia) is a disease that occurs primarily in senior dogs. It is estimated that 68% of dogs will have CCD by the time they are 15-16 years old. Dogs with CCD appear to have decreased cognitive function. And the signs of dementia in dogs may mirror those in human Alzheimer’s patients.
Stroke
Strokes in dogs occur when blood flow to the brain is interrupted. Thankfully, strokes in dogs are less common than strokes in humans, but they can occur, especially in senior dogs.
What are the signs of a brain tumor in dogs?
Now that you know which diseases might be confused with a brain tumor in dogs (especially elderly dogs), let’s take a closer look at the symptoms of brain tumors. We will explore each of the following signs of a brain tumor in dogs more in detail below:
- Seizures
- Panting and restlessness
- Balance problems or difficulty walking
- Behavior changes such as aggression, excessive whining, or mentation changes
- Circling
- Head tilt
- Head pressing
- Decreased cognitive function
- Changes in vision (including blindness)
- Abnormal pupil size and/or nystagmus (i.e. repetitive flickering or twitching eye movements)
- Changes to the appearance of the face
- Neck, back, or head pain
- Loss of appetite (i.e. anorexia)
- Vomiting and diarrhea
- Licking the air or sneezing
- Weakness and lethargy
It is important to note that the exact signs seen in a dog with a brain tumor will depend on the type of cancer present, how far the cancer has progressed, and the location where it invaded the brain.
Additionally, while I will try to identify some of the symptoms as an early, late, advanced, or end-stage sign of a brain tumor in dogs, this can get a bit murky due to the variation in tumors. Thus, looking at the progression of signs rather that the particular signs can give you a better picture of your dog’s condition.
1. Seizures
Seizures in dogs are one of the most common signs of brain tumors in dogs. However, not every dog who has a brain tumor will have seizures. If they do have seizures, dogs with a brain tumor may have focal seizures (e.g. the dog is fly biting or licking the air). Or they may experience generalized/grand mal seizures (e.g. the dog falls over, starts paddling, etc.) or tremors. Sometimes the dog could have multiple seizures within a 24-hour period of time. These are known as cluster seizures.
Dogs can develop seizures at any stage of a brain tumor. And they may worsen or become more frequent as a tumor grows and progresses.
Any dog that has a seizure should be evaluated by a veterinarian and have diagnostics like blood tests for dogs and possibly X-rays or advanced imaging. This allows the vet to identify the cause of the seizure (e.g. brain tumor, trauma, inflammation, epilepsy, etc.) and create a treatment plan.
2. Panting and restlessness
Restless behavior like panting and pacing is common in dogs with brain tumors. This can happen because the dog is painful or is aware that something is wrong. Or the dog may be panting and restless due to abnormal brain function or altered brain activity.
It is important to note, though, that restlessness and panting are not specific to brain tumors in dogs. This symptom also can be seen in the other four diseases discussed above. Plus, it may occur in many other conditions that are not specific to senior dogs or the brain.
Thus, if your dog is acting restless, you should consult your vet and monitor your dog for any additional clinical signs in the meantime.
3. Balance problems or difficulty walking
Dogs with brain tumors may also develop an unsteady gait (i.e. ataxia) and have difficulty walking. This could look like:
- Stumbling when standing up
- Incoordination when trying to lie down
- Staggering (i.e. walking with a drunken gait)
- Tripping when walking
- Leaning to one side when walking or sitting
- Crossing the front or back legs when walking
- General incoordination (i.e. a dog who is wobbly and off balance)
However, dogs with other conditions can also have balance abnormalities. For example, vestibular disease, stroke, epilepsy, or weakness and pain associated with musculoskeletal diseases (e.g. IVDD in dogs, degenerative myelopathy in dogs, etc.) can also cause a dog to appear ataxic.
If your dog is having difficulty walking, it is important to let your veterinarian know. Balance problems are abnormal for any dog. So, your dog needs a veterinary exam to determine the underlying cause and create a treatment plan.
Additionally, if you know your dog has a brain tumor and his or her balance is getting worse, please let your vet know. This could be a sign that the tumor is growing or is invading a new part of the brain.
4. Behavior changes (aggression, excessive whining, decreased mentation)
One of the more specific signs of a brain tumor in dogs is behavior changes. Because the brain is so important for regulating the chemicals and hormones that control behavior and thought processing, brain tumors can unfortunately affect a dog’s behavior.
Behavior changes can look very different depending on the dog, the tumor location, and the tumor size. Some dogs with a brain tumor may never experience behavior changes. Others may experience them very early on in the disease (sometimes this is even the first symptom dog parents notice).
Also, behavior changes can come and go. Because of this variation, when dog parents ask me, “How does a dog act with a brain tumor?” it is very difficult for me to give them a straight answer. The type of behavior changes your dog may experience can differ from dog to dog.
Let’s take a look at three common changes in detail.
Aggression
Unfortunately, one of the most common behavior changes I see in dogs with brain tumors is aggression. Brain cancer can sometimes cause the sweetest, most friendly dog to become aggressive. And the aggression can come and go and take various forms. Different types of aggression could include:
- Resource guarding—starting to protect his or her food, bed, toys, etc.
- Sudden aggression toward or fear of a family member or friend who the dog was previously comfortable with
- Newly developed aggression toward a dog or other pet in the household
- Appearing more grumpy or growly in general
If you notice any of these changes in your dog, please consult your veterinarian. Aggression is not something that you should ignore because it can progress and become dangerous. Thus, it’s important to work with your vet to determine the cause of the new behavior. It could be a brain tumor vs. a stroke vs. dementia vs pain vs. another condition. And the sooner you know the underlying cause, the sooner you can address it.
Excessive whining
Another behavior change you might notice in a dog with a brain tumor is increased whining. This symptom also can go hand in hand with the restlessness discussed above. Dogs who are experiencing brain changes from a tumor, sundowners in dogs (a component of CCD), epilepsy, or a stroke are all at risk of developing anxious behavior, including increased whining.
Often, excessive whining is most obvious in the evenings or at night. Instead of sleeping, a dog with senior dog anxiety at night might be up pacing and whining or howling. Or dog parents sometimes notice that their dog is suddenly barking at imaginary things on the walls or imaginary noises.
If you see these behaviors, please bring your dog to the vet for an evaluation.
Decreased mentation
Sometimes a dog with a brain tumor may seem to be less aware of his or her surroundings or less responsive to normal stimuli. These changes fall under the category of decreased mentation (i.e. mental status). It may seem like your dog’s attitude and personality have changed and your dog just isn’t himself or herself anymore.
Interestingly, a study of 177 dogs with secondary intracranial neoplasia revealed that mentation changes were the most common clinical sign in dogs with tumors that had spread to the brain from another location.
5. Circling
Dogs with a brain tumor may circle. This may mean they walk in circles rather than a straight line. Or they may not make complete circles but rather walk in a curved line. Either way, usually dogs will circle more to one side than the other.
If your dog is circling, please let your veterinarian know. Before the vet visit it can also be helpful to take a video of your dog’s behavior, especially if your dog does not always circle.
Circling is usually related to a brain tumor, vertigo, or a severe ear infection.
6. Head tilt
Dogs with a brain tumor may also have a head tilt (i.e. holding the head cocked to one side). And because the dog has a head tilt, he or she may be more likely to walk toward the side of the head tilt rather than in a straight line. Thus, head tilt and circling may go together. And just like circling, a head tilt could be due to a brain tumor, vertigo, seizures, or a severe ear infection.
7. Head pressing
Head pressing is another pretty obvious brain tumor symptom that dogs can develop. When a dog is head pressing, he or she will stand near an object (usually against a wall, couch, or corner) with his or head pressed against that object.
We don’t fully understand why dogs head press. But it is believed that it might give them some pain relief or help them feel secure.
Like many of the other symptoms, head pressing can be associated with epilepsy, stroke, vertigo, canine cognitive dysfunction, head or brain trauma, improper salt levels in the bloodstream, parasites, and more. So if your dog suddenly develops head pressing or is doing the behavior more often, please let your veterinarian know right away.
8. Decreased cognitive function
In addition to head pressing, another common symptom of brain tumors (or other conditions) is decreased cognitive function. Like many signs, cognitive dysfunction can look different for each dog. And it can change as the disease progresses.
Some potential indicators of decreased cognitive function include:
- Appearing lost in the home where they live
- Forgetting who familiar people or other dogs are
- Not remembering where the food bowl, dog bed, or other familiar items are located
- Forgetting previously known tricks or commands
When dogs start to show these symptoms in their senior years, it is common for dog parents to assume they are a normal part of aging. However, this is not always the case. These changes may point to a brain tumor, epilepsy, stroke, or canine cognitive dysfunction.
9. Changes in vision (including blindness)
Depending on the tumor location, dogs with brain tumors can also develop vision changes or sudden blindness. However, acute blindness could also be due to a stroke, severe seizure associated with epilepsy, trauma, or sudden acquired retinal degeneration syndrome (SARDS in dogs). And more commonly, gradual vision changes are related to other conditions like glaucoma in dogs, cataracts in dogs, or normal aging and deterioration of the eyes, not a brain tumor.
In any case, it is best to make an appointment with your veterinarian if you feel that your dog’s vision is declining or your dog suddenly goes blind. That way you can get to the bottom of the issue and take steps to treat or manage it.
10. Abnormal pupil size and/or nystagmus
Additionally, dogs can develop abnormal pupil size and/or nystagmus (i.e. repetitive flickering or twitching eye movements) if the brain tumor is located near a nerve that controls the eye. But one or both of these signs can also occur with ear infections, vertigo, growths in the ear, Horner’s syndrome in dogs, head trauma, or other conditions.
11. Changes to the appearance of the face
Some dogs with brain tumors will develop abnormal bulging around the eyes, nose, or face. This may occur if the dog had a primary tumor in or around the eyes, nose, mouth, or skull which then spread to the brain. Any sign of facial deformity (especially if sudden) should be evaluated right away by a veterinarian.
12. Neck, back, or head pain
In some situations, dog parents may notice signs of neck, back, or head pain in a dog with a brain tumor. Thus, when clients ask me, “Are brain tumors in dogs painful?”, the answer is “It depends.”
Tumors that are not invading any nearby structures where nerves are present are less likely to be painful. However, if the tumor is pressing on structures in the head (like the eyes), stretching the covering of the brain, invading the pain centers of the brain, or affecting the back or neck, this can be very painful.
Signs of pain in dogs that you might see include:
- No longer wanting to be petted on the head, neck, or back
- Flinching when certain areas are touched
- Whimpering or crying out when making certain movements
- Walking with a hunched back or kink in the neck
If you suspect your dog is in pain, please let your veterinarian know right away. Pain can negatively affect your dog’s quality of life. Thus, it is one of the symptoms you should watch closely for if your dog has a brain tumor. Also, if your dog is painful, please use caution when handling him or her. Severe pain can make dogs more prone to bite or snap if you touch them the wrong way.
13. Loss of appetite (i.e. anorexia)
Loss of appetite is another symptom that may occur in dogs with brain tumors. But this symptom can also accompany almost any disease or condition that dogs can develop. For some dogs, even the smallest amount of discomfort can cause changes in appetite.
However, just because loss of appetite is not a very specific sign, this doesn’t mean you should ignore it. Decreased eating is often one of the first symptoms that dog parents notice. And it is also one of the earliest signs that dogs exhibit for many different diseases. If you are concerned about your dog’s appetite, please make an appointment with your vet.
Additionally, if you know your dog has a brain tumor, monitoring his or her appetite after diagnosis is very important. If your dog suddenly has less interest in food (including special treats or snacks) or is not eating at all, this could be an indication that the cancer has progressed to the point where it is impacting your dog’s quality of life. And your vet may need to reassess your dog to determine if the brain tumor has changed, spread to another location, or if there is another unrelated problem.
14. Vomiting and diarrhea
In addition to a decreased interest in food, some dogs may develop vomiting or diarrhea when they have a brain tumor. Vomiting and diarrhea could occur if decreased food intake upsets the normal GI bacterial population. Also, some brain tumor medications and treatments may have side effects like gastrointestinal upset. Or it is possible that a metastatic tumor may have spread to the GI tract and caused the vomiting or diarrhea.
However, dogs with vertigo might be vomiting too. This occurs because the sense of “being lost in space” can make the dog nauseous. Plus, dogs may also vomit or have diarrhea due to a whole host of other conditions.
While vomiting and diarrhea are not very specific symptoms, you should not ignore them—especially if your dog already is not eating (or drinking) regularly, is losing weight, or has other ongoing problems. Please contact your vet if your dog has persistent or recurrent vomiting or diarrhea.
15. Licking the air or sneezing
Some pet parents also ask if excessive licking of the air or sneezing could mean that their dog has a brain tumor vs. dementia vs. another condition. This is a great question because your dog licking the air frequently or excessively sneezing could be associated with various diseases, including:
- Seizures (from epilepsy or a brain tumor)
- Allergies
- Nasal tumors in dogs or dog mouth cancer (both of which could spread to the brain depending on the tumor type)
- Severe dental disease in dogs
- Canine cognitive dysfunction
As you can see, excessive air licking or sneezing could be related to a variety of diseases. If your dog has either of these symptoms, please reach out to your veterinarian to help determine the underlying cause.
16. Weakness and lethargy
Dogs with brain tumors also tend to experience weakness and be a lethargic dog. You may see these symptoms early on in the disease progression, and they may worsen as time goes on. However, just like many of the symptoms above, weakness and tiredness are not specific to brain tumors. They could also be a sign of many other conditions.
If your dog does appear to be tired or weak, it is important to monitor him or her carefully. Does your dog still perk up for food, water, or to go outside? When your dog rests, does he or she gain more energy? Is the tiredness increasing over time? Does your dog have tremors? The answers to those questions can help guide you and your vet.
If you are concerned that your dog may be lethargic or weak and the signs aren’t improving, please consult your veterinarian. And if your dog with a brain tumor appears to be more weak or tired, please let your vet know right away. It is important to note any changes in symptoms so your vet can monitor or treat your dog accordingly.
Don’t underestimate the role you play in your dog’s health
As you can see from the long list of symptoms you just read about, there are many different signs of a brain tumor in dogs. Some of these signs are more likely to be associated with a brain tumor. But others can just as easily point toward a different senior dog disease. This can complicate matters a bit.
The key is knowing what symptoms to watch for and remembering how important it is to get your dog to the vet if you have concerns about your dog’s symptoms.
Additionally, once your dog has been diagnosed with a brain tumor (or any other disease), it is very important that you monitor your dog carefully for new or worsening symptoms. You know your dog better than anyone else, so you are the most likely to detect these changes quickly. Should you notice any worsening of the symptoms or new signs, please contact your vet promptly.
As the dog parent, your veterinarian and your dog are relying on you to be a voice for your dog. Your input is critical for reaching a diagnosis and creating the best plan possible. Although the overall prognosis for dogs with brain tumors is grim, through proper treatment or palliative care and close monitoring, you can give your dog the best quality of life possible after a brain tumor diagnosis.
What symptoms did your dog with a brain tumor exhibit?
Please comment below.
We welcome your comments and questions about senior dog care.
However, if you need medical advice, diagnosis, or treatment, please contact your local veterinarian.