Brain tumours are usually lethal in dogs, although treatment can make the last few months or years of a dog's life more comfortable. Diagnosing brain tumours can be accurately made so a biopsy isn't necessary, based just on the dog's actions. It's important to get your dog to the vet whenever they display any of these symptoms.
A dog with a brain tumour will often suddenly go blind in one or both eyes, or act as if they have gone blind for hours at a time. Blindness needs to be combined with other symptoms in order for a vet to diagnose brain tumour, because it's normal for older dogs to go blind. Breeds most prone to tumours are Boxers, Golden Retrievers and Dobermans.
Dogs with brain tumours often wander in circles as if lost, get stuck in the corner of a room and often do not seem to recognise family members. They may also not know what time it is and ask for supper even though they have just been fed.
Any time a dog has seizures, it should be treated as an emergency and the animal should be taken to the vet. Seizures in dogs look identical to seizures in humans.
If the dog is house trained and suddenly forgets where to go, this can be a symptom of a brain tumour. Other warning signs include changes in breathing, walking or loss of appetite.
The symptoms may come on gradually or they may come on all of a sudden. It's different for each dog.