The nervous system of the dog, like that of man, centers on the brain and spinal cord. From these central areas, like branches on a tree trunk, runs the complex network of the nervous system. The brain, of course, is the central repository of all motivations. What the brain commands, the rest of the body does. If the brain is troubled in any way, the entire body responds accordingly. Brain damage or inflammation (encephalitis) can throw the dog's entire nervous system off balance. Certain diseases, like distemper and rabies directly attack the dog's nervous system. Since the system is so delicate, prevention of such disease is the only way to ensure a healthy dog. Rabies leaves no survivors, and distemper may well leave a crippled dog. There are also diseases of lesser intensity that attack the nervous system only temporarily, such as eclampsia. While many of these conditions are frightening, some may clear up, provided they are treated in time.
Chorea and Fits
Sometimes as a result of distemper, your dog may suffer from chorea, a spasmodic twitching of his muscles, also called St. Vitus's dance. The area affected might be the jaw, a leg, the neck, or the whole body. If the chorea is limited to one area, your dog can live but with twitch in that area. A number of things can bring on convulsions and fits, such as a disease, sun stroke, an accident, poison, a neurological disorder, inadequate diet, over-excitement, parasites, worms, or high fevers. A fit is marked by foaming or frothing at the mouth, champing of the jaws, as though the dog were chewing gum, salivating, thrashing of the feet for no purpose, stiffening of the muscles so that the body quivers and shakes, and even unconsciousness. A fit is frightening to watch, but the important thing is not to panic. The dog generally is not dangerous. Nevertheless, you may be afraid that your dog has rabies, even though rabies is relatively rare. The animals may accidentally bite you. The fit itself is not generally the disease or ailment, and there is little you can do except to make sure that the dog does not injure himself. Take precautions that there are no objects around which can hurt him, but otherwise leave him alone while he is in the fit. When the fit subsides, you should try to make the dog as comfortable as possible: give him a blanket to keep him warm and some fresh water. Do not give him any heavy food directly after a fit. A fit may simply be from nervousness. On the other hand, it generally points to something more serious that needs professional care. A heavy infestation of worms, for instance, may lead to fits if not treated. Often you won't recognize the real problem until your dog has the convulsion. And even then a veterinarian might have difficulty diagnosing the condition. The general rule is that all dogs who have had a fit should be examined by a veterinarian.
Encephalitis is an inflammation of the brain that accompanies some of the more severe canine diseases, such as distemper. The dog may lie down and pedal with his feet, as though bicycling. The other signs are also obvious: convulsions, possibly with frothing, twitching of muscles, partial or complete loss of vision, rapidly fluctuating temperature, from very high to near normal, confusion for the dog as to where he is, partial (sometimes complete) paralysis, excessive urinating and defecating. By the time encephalitis has developed, your dog is already under professional care for the primary disease. The mortality rate is very high.