Posted on June 26, 2016
A Primer on Canine Tetanus
Odds are really good that none of the dogs you’ll ever know will develop tetanus. So, why have I chosen to write about this disease? Blame it on Facebook (FB). For those of you who use FB, when I describe the vegetative trance one can enter while scrolling through a FB news feed, you know exactly what I’m talking about. This is the state I was in when I happened to scroll past a photo of a Labrador’ish-looking dog whose facial expression appeared pretty much just like the dog pictured here. This very classic photo pulled me right out of my FB trance.
The text accompanying the photo was a plea for help in the way of “Can anyone tell me what is wrong with my dog?” The FB poster indicated that her vet had already examined her dog a few times, but there was still no diagnosis. Even with baytril (an antibiotic) and pain medication on board, her dog was steadily getting worse. Her dog was still able to walk, but appeared very stiff.
I don’t usually get involved in requests for a “photo diagnosis.” A single photo can usually translate into a dozen or more diagnoses. However, this particular photo was classic- a textbook case of tetanus. And, I knew that, without appropriate treatment administered just as soon as possible, this dog would be doomed. I felt a moral obligation to respond.
I posted a comment letting the FB poster know that her dog likely had tetanus and was in need of intensive therapy. I encouraged her to seek help ASAP, ideally by way of an emergency hospital, or veterinary specialist such as an internist or criticalist. I asked if the dog had a recent wound that would have allowed the tetanus organism to gain entry.
The response arrived within seconds. Sure enough, a week or so ago the dog had been limping due to a cut on his toe. She thanked me profusely and let me know that she would get help for her dog right away. I wished her the best of luck and our FB conversation ended.
The cause of tetanus
Tetanus is caused by Clostridium tetani, a soil bacterium that can enter the bloodstream via a wound, most commonly on the foot or in the mouth. Puppies can develop tetanus because they chew on sticks and other soil-contaminated goodies, and they have open wounds in their gums created by the loss of baby teeth.
The clostridial organism produces a toxin called tetanospasmin that binds to nerve cells and interferes with the function of a particular neurotransmitter (a chemical released from a nerve cell that transmits an impulse) responsible for inhibiting muscle contractions. Disabling this inhibitory neurotransmitter results in relentless muscle spasms.
Tetanus symptoms usually begin around the face and eyes. Dogs lose their ability to blink accompanied by changes in facial features. This classic facial appearance (the one that prompted me to respond to the FB post) is referred to as risus sardonicus.
With time, symptoms become more generalized throughout the body ultimately resulting in a spastic paralysis- the dog is unable to move at all because of muscle rigidity. Without appropriate treatment, death occurs due to paralysis of the muscles responsible for breathing.
To see a dog with tetanic symptoms, have a look at this video. Not to worry, this video has a happy ending.
There is no simple test for diagnosing tetanus. Rather, the diagnosis is made based on symptoms and the history of a wound that allowed the clostridial organism to gain entry into the bloodstream.
Treatment and prognosis
Clostridium tetani is an anaerobic bacterial organism, meaning that it thrives in environments devoid of oxygen. A wound festering beneath the skin surface is an ideal incubator. For this reason, it is important to treat the wound (if one is found) where the bacteria gained entry. This involves debridement- opening the wound and removing as much infected tissue as possible.
Appropriate antibiotic therapy is imperative. Penicillin-related drugs work well against the clostridial organism and, at least initially, they are typically administered intravenously. With improvement, oral antibiotics are appropriate. (Baytril, the antibiotic the FB dog was being treated with, is ineffective against Clostridium tetani.)
Additional treatment is dictated by the severity of symptoms. Muscle relaxants are commonly administered along with medication to reduce anxiety. If the dog is unable to eat because of “lock jaw”, nutrition is provided by way of a feeding tube. And if the dog is unable to move, intensive nursing care is required.
Dogs with tetanus are usually super-sensitive to stimuli, and sights and sounds can intensify muscle contractions. For this reason, these dogs are often sedated and kept in a dark quiet room during the recovery period. Long-term treatment- up to a month or more- is often required.
The prognosis for tetanus is good, assuming the dog receives early intervention and aggressive treatment. As with most diseases, the earlier the diagnosis is made and treatment started, the better the prognosis.
Dogs are not routinely vaccinated against tetanus because they are so much less susceptible to this disease than are other species such as horses, livestock and people. This being said, it does make sense to thoroughly clean even minor wounds, particularly those on the feet.
How the story ends
So, how did things turn out for the dog I “met” on FB? I sure wish I knew. Silly me, I failed to note the woman’s name and, because we are not FB “friends”, I am at a loss as to how to find her again. I suspect things turned out well, and I’m glad my FB conversation prompted me to teach you about tetanus!
Nancy Kay, DVM
Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
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Please visit http://www.speakingforspot.com to read excerpts from Speaking for Spot and Your Dog’s Best Health. There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at http://www.speakingforspot.com