A dog can have a convulsion as the result of poisoning, infections, eclampsia, kidney or liver disease, epilepsy or a brain tumor.
Although most seizures will last from two to five minutes, some will last only a few seconds. Signs include an inability to stand, loss of consciousness, violent muscle spasms and urine or stool discharge. After a seizure, the dog will appear confused and unresponsive. It may also salivate heavily and pace back and forth.
Attempting to handle a convulsing dog is dangerous. You could be severely bit. If the dog is in a dangerous location, try to hold the dog down gently with a blanket or move any objects that may injure the dog. Convulsing dogs do not swallow their tongues, so do not insert your fingers into the mouth of a convulsing dog.
Once the seizure has subsided, reassure the dog. Keep the dog in a dark, silent room. Call your veterinarian.