Seizures in old dogs are something concerning that require medical attention. Seizures in dogs may arise for several reasons, both inside the brain and outside the brain, and often a specific cause cannot always be found. In older dogs, seizures are particularly worrisome because they may be indicative of some serious health problems associated with aging. If your old dog never had seizures for all his life, and now has suddenly seizures, see your vet for proper diagnosis and treatment. The onset of seizures in old dogs warrants investigation.
Seizures in Dogs
Seizures are characterized by episodes of uncontrolled muscle movements and the dog often loses consciousness during these episodes. Dogs are often seen violently paddling their legs, making chewing motions with their jaws, drooling and even emptying their bladder and bowels. Afterward, dogs may act disoriented for some time.
In dogs, seizures can be caused by a multitude of problems. In very young dogs, usually under 1 year old, the underlying cause of seizures often stems from a congenital abnormality such as a liver shunt.
Older dogs, (mostly from the ages of 1 to 6 years), suffer from what's known as idiopathic epilepsy. Idiopathic is the medical term for "unknown cause" while epilepsy is the medical term to depict seizures.
It is still not well understood why many dogs are affected by seizures of unknown cause. What's known is simply the fact that for some reason, the neurons of the brain of these affected dogs are prone to getting stuck into repeatedly firing into uncontrolled bursts. Some dogs breeds appear to be more predisposed than others.
In older, senior dogs, generally over the age of 6 or 7, seizures are unlikely to be of the idiopathic epilepsy type, rather, there is often an underlying cause that requires investigation. Finding the underlying cause is important so that it can be addressed and the seizures can be attempted to be kept under control.
Causes of Seizures in Old Dogs
The causes of seizures in old dogs can be many, and therefore it is important to consult with a vet for proper diagnosis and treatment. Some old dogs can sometimes have a seizure once and then never again, while others may have repeated seizures, which point to some underlying cause that needs attention. Following is a list of potential differentials that can may trigger the onset of seizures in old dogs.
Brain Tumors in Old Dogs
It's unfortunate, but one of the primary causes for the onset of seizures in old dogs are brain tumors. In this case, therefore, a tumor is quite high on the list of potential causes.
Brain tumors in dogs can be diagnosed through advanced imaging such as a CT scan or an MRI. Spinal taps may be also performed so to rule out any potential inflammatory causes, but these are considerably less common. All these diagnostics can be quite expensive. An MRI alone may cost around $1500 or more. If a tumor is found, the surgery may be upwards of $5,000 to 6000, but in some cases, the tumors may be inoperable.
When dog owners are understandably unable to afford such advanced imaging diagnostics and are not interested in pursuing surgery if a tumor is found, affected dogs may be treated empirically. Treatment may involve use of medications to control seizures such as phenobarbital or potassium bromide or the newer seizure medication zonisamide. Bloodwork will need to be taken so to check the state of the dog's liver considering that some anticonvulsants can be troublesome.
Other problems affecting the brain that may cause seizures include infection, bacterial abscesses in the brain meningitis, head injury and strokes (rare in dogs), but again, in an older dog unfortunately brain tumors are often the main culprit. Consulting with a veterinary neurologist may be insightful.
" Seizures in an older dog are most often due to a brain tumor. The frequency of seizures will continue over time as the tumor grows. The medications can help to reduce the seizures during this time, however you will get to a point where the medication alone is not enough and more medications will have to be added."~Dr. G, veterinarian
Metabolic Diseases in Old Dogs
Old dogs are often prone to a variety of metabolic disease. Although, metabolic disorders are a less common underlying cause of seizures in old dogs, they are worthy of consideration.
Liver failure or kidney failure can cause seizures in affected dogs. For example, in the case of liver failure, since the liver can no longer effectively remove toxins from the blood, such toxins accumulate in the dog's bloodstream, and end up reaching the brain where it wrecks havoc, the medical term is hepatic encephalopathy, potentially causing seizures.
Your vet may want to run a a blood panel so to rule out any possible metabolic diseases which can cause trigger an onset of seizures in old dogs.
A Blood Glucose Issue
Sometimes, a seizure may arise from a blood glucose problem. More specifically, low blood glucose medically known as hypoglycemia. A seizure in old dogs due to low glucose levels is often the result of some type of pancreatic cancer that secretes insulin (insulinoma).
This cancer causes insulin levels to get too high, which cause the drop in blood sugar and subsequent seizures. This is the opposite of what happens in diabetes, where low blood insulin causes a spike in high blood sugar. Insulin and blood sugar act in a similar fashion as a see-saw; when the insulin is elevated, the blood sugar is lowered, explains Dr. Rebecca.
A blood panel and urinalysis can help direct towards the diagnosis of this problem. Definite diagnosis is obtained by sending a blood test to a lab so to measure the dog's insulin levels. This is a specialized tests that is not part of the routine blood panels commonly run in vet's offices.
Phenobarbital will not help to address these seizures. Instead, prednisone may help or other drugs may be needed such as diazoxide and Palladia may help. Surgery can help in some cases. In some cases, uncontrolleed high blood glucose levels as a result of diabetes may cause seizures.
Exposure to Toxins
Seizures in dogs often can be precipitated by exposure to toxins and this can happen in dogs of any age. If your dog was recently exposed to any toxins such as strychnine, rat bait, snail bait, lead, moldy walnuts, pesticides or other types of toxins, make sure you make your vet aware of it. Chances are, the affected dog will recover if the vet provides prompt supportive care or provides an antidote if applicable.
Sometimes, cheap, over-the-counter products meant to get rid of fleas may cause an onset of sudden seizures in dogs. On top of that, consider that ingesting certain over-the-counter of prescription medications you may have accidentally dropped on the floor and which ended ingested by your dog, can cause seizures as a side effect.
Sometimes, what looks like a seizure is actually the dog collapsing due to an underlying heart problem. Many old dogs suffer from heart problems and these may lead to "fainting' episodes. Such episodes often occur when the dog's heart rate goes up such as when the dog is excited or stressed and there is interruption of blood to the brain.
Affected dogs likely suffer from endocardiosis which is heart valve disease often common in small dogs. Because the heart is unable to keep up with the demands a sort of fainting fit occurs, explains veterinarian Dr. Scott Nimmo. Usually, after the dog is allowed to rest a bit, the dog recovers. It's important therefore to try to limit as much stressful or excessively excited situations.
Other Possible Causes
There are several other potential causes such as electrolyte disturbances, a pituitary tumor causing Cushings disease that has grown large enough as to cause seizures, hypothyroidism (an underactive thyroid) and more. It's therefore important to see the vet so to screen for different possible disorders.