If your old dog experiences seizures out of the blue and shaking episodes, this may be alarming and confusing for any dog owner.
Understanding why these symptoms occur suddenly in older dogs is crucial, as they can be a sign of serious underlying health conditions.
When an old dog has seizures out of the blue and shaking, it’s important to observe the frequency, duration, and severity of these episodes.
While occasional mild tremors may happen due to age or minor stress, sudden and repeated seizures and shaking should never be ignored.
We outline the common reasons behind old dog seizures out of the blue and shaking, and what you should do to ensure your senior pet gets the care they need.
Here’s Why Old Dog Seizures Out of the Blue and Shaking Happens
Old dog seizures out of the blue and shaking often occur due to underlying medical conditions such as brain tumors, liver or kidney disease, toxin exposure, low blood sugar, or neurological disorders.
As dogs age, their bodies become more vulnerable to these issues, which can disrupt normal brain function and trigger sudden seizures or involuntary muscle tremors.
While some episodes may appear random, they usually stem from a deeper health problem that requires veterinary diagnosis and treatment.
Common causes of old dog seizures out of the blue and shaking
Old dog seizures out of the blue and shaking also result from multiple medical conditions:
1. Idiopathic epilepsy (less common in old dogs)
While idiopathic epilepsy is more commonly diagnosed in younger dogs, some older dogs may experience their first seizure late in life.
These seizures are typically generalized and may involve shaking, loss of consciousness, and muscle twitching.
Since idiopathic epilepsy is not linked to structural brain abnormalities, diagnosing it in older dogs is usually a process of ruling out other causes.
However, it’s rare for a dog to develop epilepsy for the first time in old age.
So, if your old dog is suddenly having seizures out of the blue and shaking, it’s more likely caused by an underlying medical issue.
2. Brain tumor
A very common cause of seizures in senior dogs is a brain tumor.
As dogs age, the risk of developing a tumor in the brain increases.
Brain tumors may exert pressure on certain parts of the brain, leading to neurological symptoms like seizures, uncoordinated movements, and shaking.
If your old dog suddenly starts having seizures and shaking episodes without any previous history, a brain tumor should be strongly considered.
Advanced imaging like MRI or CT scans are needed to confirm this diagnosis.
3. Liver disease (hepatic encephalopathy)
In older dogs, liver disease can lead to a condition called hepatic encephalopathy.
When the liver fails to properly filter toxins from the blood, these toxins can accumulate and affect the brain.
One of the hallmark signs of hepatic encephalopathy is old dog seizures out of the blue and shaking.
These neurological signs are usually accompanied by vomiting, confusion, disorientation, or head pressing.
Liver dysfunction is more likely in senior dogs and should be considered if other signs such as yellowing of the eyes or gums, loss of appetite, or weight loss are observed.
4. Kidney failure
Just like the liver, failing kidneys in senior dogs can allow toxins to build up in the bloodstream, leading to tremors and seizures.
Old dog seizures out of the blue and shaking may be signs of advanced kidney disease.
This is often accompanied by increased drinking and urination, lethargy, and pale gums.
Regular blood tests and urine analysis are vital for detecting kidney issues early in older dogs.
Related: Old dog diarrhea and shaking (Causes and treatment)
5. Hypoglycemia (low blood sugar)
Senior dogs, especially those with diabetes or insulin-secreting tumors, may develop dangerously low blood sugar levels.
When glucose levels drop too low, the brain is deprived of energy, which may trigger seizures and shaking.
Symptoms may include sudden collapse, weakness, shaking, disorientation, and even loss of consciousness.
Hypoglycemia is a medical emergency, especially in older dogs.
6. Toxin exposure
Older dogs, due to age-related cognitive decline, may become more prone to accidental poisoning.
Ingesting toxins like chocolate, rodenticide, moldy food, or household chemicals can cause seizures, muscle tremors, and shaking.
If an old dog begins showing symptoms of seizures out of the blue and shaking and you suspect they may have ingested something toxic, seek immediate veterinary help.
7. Canine Cognitive Dysfunction (dog dementia)
Similar to Alzheimer’s disease in humans, canine cognitive dysfunction can affect older dogs.
Along with disorientation and confusion, some dogs may exhibit physical symptoms like trembling or mild seizure-like activity.
While seizures are less common in dementia cases, shaking episodes, pacing, and night-time restlessness are often observed.
8. Electrolyte imbalances
Older dogs are more vulnerable to imbalances in electrolytes such as calcium, potassium, and sodium.
These imbalances can affect muscle and nerve function, leading to tremors or seizures.
Conditions like Addison’s disease, dehydration, or underlying endocrine problems may disrupt electrolyte levels and cause old dog seizures out of the blue and shaking.
9. Heart problems
Heart issues in older dogs can reduce oxygen supply to the brain, which may result in fainting (syncope), seizure-like activity, or tremors.
If your old dog is collapsing and shaking, especially after exercise or excitement, cardiac problems should be evaluated.
An irregular heartbeat or reduced blood flow can mimic seizure episodes and should be checked through ECG and cardiac workups.
10. Pain or arthritis flare-ups
Chronic pain in older dogs, such as that caused by arthritis or spinal problems, may cause shaking or trembling.
While this is not a seizure, it may be mistaken for one.
An old dog shaking and appearing distressed might be in pain rather than having a true seizure.
Observe for other signs such as limping, reluctance to move, or vocalizing when touched, to determine if pain is the culprit.
What to do if your old dog is having seizures and shaking
If your old dog suddenly starts experiencing seizures out of the blue and shaking, take the following steps:
1. Stay calm and keep your dog safe:
During a seizure, make sure your dog is in a safe environment—away from sharp objects, stairs, or furniture.
Do not try to hold their tongue or restrain them. Instead, speak in a calm voice and dim the lights if possible.
2. Time the episode:
Note how long the seizure lasts and any behaviors before or after.
A seizure lasting more than 5 minutes (status epilepticus) is a medical emergency and requires immediate intervention.
3. Record the symptoms:
Capture a video of the episode if you can.
This can help your veterinarian better understand the nature of the shaking or seizure.
4. Monitor post-seizure behavior:
After a seizure, many dogs go through a recovery period where they may appear dazed, uncoordinated, or even temporarily blind.
Monitor your dog closely during this time.
5. Seek veterinary evaluation immediately:
Any old dog seizures out of the blue and shaking should be taken seriously.
Since senior dogs are more likely to suffer from underlying systemic issues, diagnostic testing is crucial.
6. Perform diagnostics:
Your veterinarian may recommend bloodwork, urinalysis, liver and kidney panels, and advanced imaging like MRI or CT scans to identify the root cause.
7. Follow treatment and management plans:
Treatment will depend on the diagnosis.
Anticonvulsants may be prescribed for ongoing seizures.
If an underlying condition like liver disease or a brain tumor is identified, specific treatment will be needed.
8. Ensure a safe environment at home:
Avoid household toxins, provide non-slip floors, keep routines consistent, and monitor water and food intake to reduce stress and injury risk.
Key Takeaway
When an old dog shows signs of seizures out of the blue and shaking, it often points to an underlying medical issue that requires attention.
While some causes may be benign or manageable, others—like brain tumors or organ failure—can be life-threatening if ignored.
Never assume that seizures in older dogs are just “old age.” These episodes are not normal and should prompt an immediate visit to the vet.
The sooner you identify and address the cause, the better your senior dog’s quality of life and chances of recovery.
Always monitor, document, and seek professional care when these troubling symptoms arise.
Your aging dog depends on you to catch the signs early and get them the help they need.