Lockjaw, also known as tetanus, rarely occurs in dogs. It's quite possible a small animal veterinarian practicing in the United States can go through her entire career without seeing a case. Anyone who has witnessed a dog with lockjaw -- his mouth stuck in a frightening grimace -- isn't likely to forget it. Tetanus shots are not one of the core canine vaccines.
The bacterium Clostridium tetani, found in soils, causes tetanus. According to the Merck Veterinary Manual, Clostridium tetani produces a neurotoxin in necrotic, or dying, tissue. While people and horses are the most vulnerable species, dogs aren't exempt. Because Clostridium tetani is anaerobic, meaning it doesn't require air to thrive, it generally occurs in canines because of puncture wounds. You might not realize your dog has suffered an injury if the wound opening is very small or healed over.
An inability to move the jaw isn't the only symptom of tetanus in canines. Other symptoms include fever, excessive salivation, respiratory problems, constipation, a stiffening body, ear and tail erection, odd gait, paralysis and spasms. Affected dogs can die without treatment. If you notice any of these symptoms, or your dog has a puncture or dirty wound, get him to the vet as soon as possible.
Your vet will prescribe antibiotics, often penicillin, to kill the bacteria. She'll need to sedate your dog if he's experiencing seizures, along with injecting medication to loosen his muscles. Seriously afflicted dogs might receive tetanus antitoxin, derived from equine or human blood. While antitoxin can aid your dog, it brings additional risks. Because it consists of the blood of a foreign species, it can cause serious immune reactions.
If he survives, it might take weeks or even months for your dog to fully recover from tetanus. Dogs with lockjaw become extremely sensitive to light and sound. He might require prolonged hospitalization, and when permitted to go home must stay sedated in a dark room with little noise or other stimulation. Until his jaw relaxes, you'll have to feed him through a tube or give him liquid meals. Place him on soft bedding and gently move him regularly to prevent bedsores. He might require a urinary catheter in order to pee and you might need to give him enemas until he can move his bowels on his own.
The tetanus vaccine is not given to dogs routinely, but ask your vet if your dog is at risk and vaccinate accordingly. If you live on a farm or take your dog hunting or hiking in wilderness areas, a tetanus shot might be recommended. Urban and suburban canines are unlikely to encounter the bacterium. If your dog suffers a puncture wound, take him to the vet for treatment and a tetanus shot.