Watching your dog have a seizure can be one of the most stressful things to go through as a dog parent. Seizures can range from a partial seizure to a grand mal seizure, with your dog suffering from mild facial twitching all the way to being on their side, paddling, and losing control of their bowels and bladder. There are numerous causes of seizures in dogs, including severe dehydration. While mild dehydration is very unlikely to cause a seizure, severe dehydration can cause a cascade of events that may end up in your dog having a seizure.
How Can Dehydration Cause a Seizure?
Severe dehydration can cause a seizure for two main reasons: dehydration is accompanied by heat stroke, or dehydration causes the sodium level in the blood to become severely elevated. A seizure that occurs in a dog due to dehydration will typically be a grand mal seizure. You may first notice your dog has become weak and is having trouble walking, breathing, and otherwise acting abnormal. As they get worse, these signs may progress into a full-blown seizure.
Dehydration With Heat Stroke (Hyperthermia)
If your dogs’ internal body temperature goes above 106 degrees Fahrenheit, they are at risk for severe internal organ damage. At this temperature, your dog’s internal organs will start to shut down. This can trigger a seizure that may be difficult to control as the other organs struggle to continue working. The longer your dog’s body temperature is elevated, the more damage can be done to both the brain and other organs. Eventually, if aggressive care is not provided, your dog can pass away.
If you suspect your dog is suffering from heat stroke, you need to get them to a veterinarian as soon as possible. Forcing your dog into a cold bath and/or forcing them to drink water will not fix the problem. In fact, it may make things worse. Your dog will need to be put on aggressive IV fluids in addition to other medications and monitoring to evaluate and treat any damage the hyperthermia has caused.
Dehydration That Causes an Elevated Blood Sodium Level
If your dog is severely dehydrated, this may cause the sodium level of their blood to become elevated. A significantly increased blood sodium level can cause your dog to have seizures. These seizures can be extremely difficult to control as your dog’s sodium level has to be slowly decreased to avoid brain swelling. If the sodium drops too quickly, this can result in cerebral edema, or brain swelling, and may result in irreversible damage.
We can see this type of dehydration occur after a dog goes to the beach and drinks excessive amounts of salt water, gets into the stash of winter salt and/or eats it outside, eats homemade Play-Doh, is given inappropriate amounts of charcoal to help with a toxin ingestion, human medication toxicity, etc. These cases absolutely need around the clock care as the blood sodium level is treated and closely monitored.
What About Mild Dehydration?
Mild dehydration, that seen from a few episodes of vomiting, diarrhea, or after a long hike, should not typically cause a seizure. With that said, if your dog is prone to having seizures, any stressors in the body such as mild dehydration may cause a seizure. Mild dehydration may or may not require veterinary care. If your dog is calm and able to drink small amounts of water at a time without vomiting, they may recover well on their own. However, if your dog has persistent abnormalities such as diarrhea, vomiting, anorexia, etc., then you should have them seen.
What Is a Grand Mal Seizure in a Dog?
A grand mal seizure is what most people think of when they hear the word seizure. It involves loss of consciousness and loss of voluntary muscle movement with all of the muscles of the body also moving on their own sporadically. Typically, dogs will lie on their side, paddling or holding their legs straight out while the rest of their body convulses. Dogs will typically urinate and defecate without knowing it and often drool profusely as they are unable to swallow.
A typical seizure will be over in less than a minute. However, depending on the cause, sometimes once a dog starts to seize, they will not stop without emergency veterinary intervention. If your dog will not stop after a few minutes, or has multiple seizures in a row, seek immediate veterinary care.
After a typical grand mal seizure is over, your dog will be in the post-ictal phase. Your dog may lose their vision, have difficulty walking, and even have temperament changes. This phase may last for minutes to hours. If there are underlying causes to a seizure, your dog may never normalize, or even never regain consciousness.
What Are Other Causes of Seizures in a Dog?
Aside from dehydration which we discussed, your dog may suffer from seizures due to a high blood pressure, a brain tumor, metastatic cancer, kidney and/or liver disease, and head trauma. They may also have an infection, meningitis, or even idiopathic epilepsy. It can sometimes be difficult to determine the cause of seizures in your dog. Your veterinarian will always start with full bloodwork. However, an MRI and cerebrospinal fluid (CSF) tap is often needed to determine the cause.
While not common, severe dehydration in a dog can cause seizures. We will most typically see this occur in a dog that is dehydrated as they are also suffering from heat stroke, and/or a dog whose sodium level has become exceptionally elevated. Both of these tend to cause a grand mal seizure and should always be treated and managed by a veterinarian. If your dog is so severely dehydrated that they are having a seizure, you should seek immediate veterinary care for them. If left untreated, or treated inappropriately, your dog can pass away if they are having a seizure from severe dehydration.