Tetanus
Clostridium tetani infection
Also known as: Lockjaw
CatDogUrgency: Emergency
Clostridium tetani infection
Also known as: Lockjaw
In short
Tetanus is a rare but life-threatening bacterial infection in dogs and cats. Caused by toxins from Clostridium tetani bacteria entering a wound, it leads to severe muscle stiffness, lockjaw, and spasms. Learn about the signs, diagnosis, and intensive care required for recovery.
TL;DR. Tetanus is a severe, life-threatening neurological condition caused by bacterial toxins entering a wound, resulting in extreme muscle stiffness, lockjaw, and potentially fatal breathing complications.
Tetanus toxin travels backwards through the nerves to block inhibitory signals in the central nervous system.
Tetanus is an uncommon but highly serious disease that affects the nervous system of dogs and cats. It is characterized by the sustained contraction of muscles without relaxation, leading to extreme stiffness. The condition is caused by a powerful toxin called tetanospasmin, which is produced by the bacterium Clostridium tetani. This bacterium is anaerobic, meaning it thrives in environments that lack oxygen, such as deep, enclosed wounds.
When Clostridium tetani bacteria contaminate a wound, they multiply and release tetanospasmin. This toxin binds irreversibly to the nerve terminals in the body. It then travels along the nerves to the central nervous system, where it blocks the release of inhibitory neurotransmitters (the chemical messengers that tell muscles to relax). Without these inhibitory signals, the motor nerves fire continuously, forcing the muscles into a state of constant, painful contraction.
While humans and horses are highly sensitive to tetanus, dogs and cats are fortunately more resistant to the toxin. However, when an infection does take hold in a dog or cat, it can progress rapidly and become a life-threatening emergency. Understanding the signs and seeking immediate veterinary care is vital for your pet's survival.
Tetanus is not contagious; a pet cannot catch it from another animal. Instead, it is acquired from the environment. Clostridium tetani bacteria exist in soil, dust, and manure as highly resilient spores. These spores are incredibly hardy, as noted in a leading veterinary internal medicine reference:
"The spores are resistant to boiling water and an autoclave temperature of 120°C for up to 20 minutes. However, the vegetative phase of this bacterium is susceptible to chemical and physical inactivation. Organisms can be isolated from the feces of dogs, cats, and humans, but presence of the organism does not indicate infection because not all strains possess the plasmid."
The primary risk factor for developing tetanus is wound contamination. Common triggers include:
Because the bacteria thrive in oxygen-deprived environments, deep, narrow puncture wounds that heal over quickly on the surface provide the perfect breeding ground for the spores to germinate, multiply, and release their deadly toxin. There are no known breed predispositions for tetanus in either dogs or cats.
The symptoms of tetanus can develop anywhere from a few days to several weeks after the initial wound occurred. The signs may start localized to the area near the wound but often progress to affect the entire body.
Risus sardonicus is a cardinal sign of tetanus, characterized by a wrinkled forehead and stiffly erect ears.
As a leading veterinary critical care textbook notes:
"Involvement of the head can lead to spasms of the masticatory and pharyngeal muscles, causing trismus (lockjaw) and dysphagia. This can be exacerbated functionally by increased salivation, increased bronchial secretions, and increased respiratory rate resulting from involvement of the parasympathetic and somatic cranial nerve nuclei."
Diagnosing tetanus is primarily presumptive, meaning your vet will make a diagnosis based on the pet's clinical signs and a history of a recent wound. Because the toxin binds quickly to the nerves, waiting for laboratory confirmation before starting treatment is dangerous.
To support the diagnosis and rule out other conditions, your vet may perform several tests:
Tetanus requires immediate, aggressive, and often prolonged veterinary treatment. Therapy is aimed at neutralizing the remaining toxin, eliminating the bacteria, controlling muscle spasms, and providing intensive supportive care.
If first-line antibiotics are not tolerated or unavailable, alternative antibiotics may be used, including:
Supportive care is the cornerstone of tetanus recovery. Because sensory stimuli (like bright lights, sudden noises, or touch) can trigger severe, painful muscle spasms, hospitalized pets must be kept in a dark, quiet, heavily padded room.
If the pet cannot swallow, a feeding tube may be placed. Intravenous fluids are administered to maintain hydration, and urinary catheters may be required if the pet cannot urinate on its own. Physical therapy is initiated once the spasms begin to subside to prevent permanent muscle contracture.
A quiet, dark environment is essential during recovery to prevent sensory stimuli from triggering painful muscle spasms.
The prognosis for tetanus varies significantly depending on the severity of the disease.
Recovery from tetanus is a very slow process. As a leading veterinary textbook explains:
"Neuronal binding of toxin is thought to be irreversible. Recovery requires the growth of new nerve terminals, which explains the long duration of tetanus."
It can take several weeks to months of dedicated nursing care for a pet to regain full mobility and normal muscle function.
Unlike humans and horses, dogs and cats do not receive routine tetanus vaccinations. Because of their natural resistance to the toxin, the risk of the vaccine outweighs the risk of contracting the disease.
Prevention relies entirely on proper wound management:
Tetanus is a veterinary emergency. If your pet has a history of a recent wound and begins showing any of the following signs, contact your veterinarian or an emergency animal hospital immediately:
Treatment must be prescribed by a licensed veterinarian based on your pet. Specific drug doses are intentionally not shown here.
Tetanus is a rare but life-threatening bacterial infection in dogs and cats. Caused by toxins from Clostridium tetani bacteria entering a wound, it leads to severe muscle stiffness, lockjaw, and spasms. Learn about the signs, diagnosis, and intensive care required for recovery.
risus sardonicus、trismus、Dysphagia、Recumbency、Stiff gait、elevated tail、enophthalmos、erect ears
Measurement of serum antibodies to tetanospasmin、Anaerobic culture of wound、Electromyography、Gram stain of wound smear、Presumptive diagnosis based on clinical signs and history of a recent wound、Radiography
Treatment must be prescribed by a licensed veterinarian based on your pet. Specific drug doses are intentionally not shown here.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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