What is tetanus?
Tetanus is a medical condition caused by a toxin. This toxin, produced by the bacteria Clostridium tetani, affects the nerves, spinal cord, and brain, leading to hyperexcitability, resulting in muscle spasms.
Although tetanus can occur in dogs and cats, it is uncommon in both species. Cats are less susceptible to the effects of tetanus toxin than humans, horses and dogs.
How do cats get tetanus?
Tetanus is typically caused by C. tetani bacteria entering a wound. Spores of C. tetani are widespread in the environment. They are shed in animal feces and can survive for years in dirt and dust. C. tetani does not cause problems in an animal’s gastrointestinal tract or on the skin, but when it enters a low-oxygen environment (such as inside a puncture wound) it can rapidly reproduce and produces a toxin known as tetanospasmin. This toxin enters the surrounding nerves then travels up the nerves to the spinal cord and the brain.
Signs of tetanus most commonly develop 5 to 10 days after the initial wound occurred. In some cases, however, signs may be seen as early as three days after exposure or as late as three weeks after exposure.
What are the clinical signs of tetanus?
In cats, tetanus can take two forms. Localized tetanus is the more common form that occurs in pets.
- Affected cats develop muscle rigidity (stiffness) in the limb or muscles closest to the wound.
- Muscle tremors may occur.
- Localized tetanus can progress to generalized tetanus with time, although this does not always occur.
Generalized tetanus affects widespread areas of the body.
- Affected animals may walk stiffly, with the tail held up or extended out behind them. These animals may become so stiff they are unable to bend their legs to stand. Many affected animals develop a “sawhorse” stance, with all four legs held in rigid extension.
- The muscles of the face are often affected in generalized tetanus. Many animals develop elevated third eyelids, a wrinkled forehead due to muscle spasms, and lips held back in an expression termed “risus sardonicus” (Latin for “sinister smile”).
- The jaws are often held rigidly closed, which is why tetanus is often called lockjaw.
- Affected cats may be unable to swallow, leading to eating difficulties and excessive salivation.
- In some cases, tetanus may lead to muscle spasms in the throat or diaphragm (the muscle that controls breathing), making it difficult for cats to breathe.
- Many patients with generalized tetanus also develop a fever. This fever is typically not caused by the bacterial infection itself but by the heat generated from constant muscle contractions.
How will my veterinarian diagnose tetanus?
Your veterinarian will typically diagnose tetanus based on exam findings. In some cases, they may find a wound when they physically examine your cat, further supporting the diagnosis.
There are tests available that can be used to look for the presence of tetanus toxin or C. tetani bacteria, but these tests are unreliable and not typically recommended.
If tetanus is suspected, your veterinarian may perform tests to assess your cat’s health status. These tests may include blood tests and urinalysis (to assess your cat’s overall health and organ function), electrocardiogram (to assess heart function), and chest X-rays (to look for the presence of secondary infections and other disorders).
How is tetanus treated?
Tetanus antitoxin may reduce the severity of clinical signs if it is administered early in the course of disease. The antitoxin works by attaching to the circulating tetanus toxin, preventing it from attaching to the nerve cells. However, the antitoxin has no benefit once the toxin attaches to the nerves. In addition, tetanus antitoxin may cause significant side effects. Your veterinarian will determine whether tetanus antitoxin is appropriate in your cat’s care.
"Cats with tetanus require intensive nursing care."
Antibiotics are also used in the treatment of tetanus. While antibiotics have no effect on the toxin, they help eliminate the C. tetani bacterial infection, which stops the release of further toxin. There are a variety of antibiotics that are effective against C. tetani, including penicillin G and metronidazole. Your veterinarian will select the appropriate antibiotic for your cat.
If your veterinarian can identify a wound, they may surgically debride and flush it. This procedure involves removing all dead tissue around the wound, with the goal of physically removing as much of the C. tetani bacteria as possible. Rapidly decreasing the number of C. tetani bacteria can provide more rapid control of tetanus.
Cats with tetanus require intensive nursing care.
- Intravenous fluids are often used to prevent dehydration.
- A feeding tube may be required if the cat is unable to eat.
- The cat must be kept on soft bedding to prevent pressure sores and must be turned regularly.
- The cat must be kept in a dark, quiet area to decrease stimulation, because sounds and bright lights can worsen the muscle spasms.
- Medications may be given to decrease the strength and severity of these muscle spasms, including sedatives and muscle relaxants. Cats on these medications must be closely monitored for potentially serious side effects, such as worsening respiratory depression.
What is the prognosis for tetanus?
The prognosis depends on the severity of the disease. Localized tetanus has a better prognosis than generalized tetanus. If a wound can be identified and debrided, it improves the prognosis.
Most cats develop localized, self-limiting disease, which responds to appropriate early treatment. Improvement is often seen within one week of treatment, although it may take 3 to 4 weeks for full recovery. If a cat is recumbent (unable to stand) or has secondary complications such as pneumonia, the prognosis becomes worse. In three reported cases of localized tetanus in cats, all 3 cats survived with treatment.
How can I prevent tetanus in my cat?
Cats show a low susceptibility to tetanus. Therefore, tetanus vaccination is not recommended. The most effective way to prevent tetanus is to ensure that all wounds receive prompt veterinary treatment. Wounds should always be flushed thoroughly and treated with antibiotics to help remove C. tetani spores and prevent infection.
If your cat develops muscle rigidity or other signs of tetanus following a wound or other injury, contact your veterinarian immediately for assessment.
