Tetanus, also known as lockjaw, is a serious illness caused by a bacterial toxin that affects the body’s nerves and muscles. The toxin is produced by the bacterium Clostridium tetani, which is found in soil, dust, and manure. Tetanus cannot be spread from person to person. So can your body fight off tetanus infection on its own without medical intervention? Let’s take a closer look.
How is tetanus contracted?
Tetanus bacteria and spores are present everywhere in the environment, including in soil, dust, and animal/human feces. The spores can survive for years in the environment. The illness occurs when tetanus spores enter the body through a wound or cut in the skin. The spores germinate into bacteria that produce a potent neurotoxin called tetanospasmin. This neurotoxin causes painful muscle contractions and spasms.
Common causes of tetanus infection include:
- Puncture wounds from nails, sewing needles, splinters, etc.
- Lacerations, burns, fractures, crush injuries
- Injecting recreational drugs with contaminated needles
- Body piercing procedures with contaminated equipment
- Unhealed umbilical stump in newborns if cut with unsterile instrument
- Animal bites
As long as the skin barrier is intact, tetanus spores cannot invade the body on their own and cause disease. Any skin breach provides an entry point for the spores to enter and cause infection.
What happens once tetanus spores enter the body?
When tetanus spores gain entry into the body through a wound, they begin to multiply rapidly. The bacteria produce tetanospasmin, which binds and blocks nerve endings.
The toxin spreads via circulation throughout the body. It affects inhibitory neurons in the central nervous system that control muscle contractions. With these neurons blocked, muscles start to contract uncontrollably.
The jaw and neck muscles are usually affected first due to their proximity to the central nervous system. This causes the first symptoms of lockjaw and stiffness/spasms in the neck and throat. As toxin production continues, other muscles throughout the body become affected.
Without treatment, tetanus toxin can paralyze muscles that control breathing, eventually leading to suffocation and death in 10-20% of cases.
Can the immune system clear tetanus infection on its own?
Unfortunately, the body’s immune system cannot clear tetanus infection by itself once the spores have germinated and started producing toxin.
Here are some reasons why:
- Tetanus bacteria remain localized to the wound site; they do not spread in the bloodstream where immune cells can reach them.
- The tetanus toxin produced binds irreversibly to nerve endings.
- The toxin itself helps tetanus bacteria evade the immune response.
- Tetanus bacteria have protective capsule and spores that are resistant to immune destruction.
In particular, the tetanus toxin has several properties that allow it to evade and suppress the immune system:
- The toxin binds very tightly to nerve cells and cannot be removed by immune cells.
- It travels retrograde (backwards) within nerves so immune cells cannot detect or neutralize it.
- It inhibits the release of neurotransmitters important for an immune response.
- The toxin prevents recruitment of protective immune cells to the central nervous system.
Therefore, once tetanus infection sets in, the body is unable to mount an effective immune response against either the bacteria or the potent toxin produced by them. This allows the bacteria to keep producing more toxin unfettered, causing progressive muscle spasms and neurological dysfunction.
What is the importance of tetanus vaccination?
Vaccination is the only effective way to prevent tetanus infection and disease.
The tetanus vaccines work by eliciting tetanus toxin-specific antibodies (immune proteins) that remain circulating in the body. If a vaccinated individual suffers a wound with entry of tetanus spores, these pre-formed antibodies can bind and neutralize the tetanus toxin before it binds nerve cells.
This prevents progression of tetanus disease. The vaccines provide long-lasting immunity against tetanus toxin. Even if tetanus spores enter the body through a wound, the antibodies can rapidly clear the toxin and bacteria.
Being up-to-date with the recommended tetanus vaccine shots ensures individuals have adequate circulating antitoxin antibodies to fight tetanus infection. The tetanus vaccine is recommended as part of routine childhood and adult immunization schedules.
Without proper tetanus vaccination, individuals would be susceptible to tetanus infection from any skin breach throughout life. Proper wound care alone cannot prevent tetanus disease in unvaccinated individuals.
Tetanus vaccination schedule
The CDC recommends the following routine tetanus vaccine schedule:
- DTaP vaccine: 5 doses between 2 months to 6 years old
- Tdap vaccine: 3 doses between 11-12 years old and during each pregnancy
- Td vaccine booster: Every 10 years from preschool to adulthood
Vaccination is also recommended for certain wound management as follows:
- Clean minor wounds: Ensure being up-to-date with routine recommended tetanus shots.
- All other wounds: Get Td or Tdap vaccine if more than 5 years since last tetanus booster.
Having the complete recommended vaccine schedule ensures long-term immunity against tetanus infection.
What is the treatment for tetanus infection?
There is no way for the body to fight off tetanus infection on its own once toxin production has started. At that point, tetanus disease can only be managed medically.
Treatment involves:
- Neutralizing tetanus toxin: Tetanus immune globulin (TIG) containing tetanus antitoxin antibodies is injected to bind and neutralize unbound toxin.
- Stopping toxin production: Antibiotics like metronidazole are used to halt bacterial growth and toxin production.
- Controlling muscle spasms: Medications like diazepam help relax muscles and control painful spasms.
- Supportive hospital care: Mechanical ventilation, fluids, nutrition may be required depending on severity.
- Wound care: Thorough cleaning and debridement of the wound to remove any bacteria.
Along with the above measures, tetanus vaccination is also administered to boost immunity in unvaccinated or inadequately vaccinated individuals.
With modern intensive care, the mortality rate from tetanus has reduced to 10-20%. However, recovery can be prolonged with the need for months of rehabilitation and ventilation support.
Can tetanus infection cause long-term consequences?
Tetanus infection can lead to serious long-term consequences even after recovery, including:
- Permanent nerve damage: The tetanus toxin can cause permanent damage to nerve cells and chronic neurological dysfunction.
- Chronic pain and spasms: Some patients suffer from residual muscle pain and spasms long after the acute infection.
- Bone and joint problems: The severe muscle spasms can lead to broken bones and joint dislocations with prolonged immobilization.
- Breathing problems: Ventilator dependence for weeks can result in permanent lung damage and respiratory impairment.
- Post-traumatic stress: Many tetanus survivors experience PTSD and emotional distress from the traumatic and painful experience.
Completing rehabilitation and physical therapy improves long-term outcomes but cannot fully reverse damage from tetanus in some patients.
Can previous tetanus infection provide immunity?
Having a tetanus infection does not provide immunity against future infections. This is because:
- Natural tetanus infections do not produce lasting antitoxin antibodies.
- The tetanus toxin binds permanently to nerves and does not circulate to induce an immune response.
- The tetanus bacteria remain localized and do not spread systemically.
Therefore, people who have had tetanus infection in the past remain fully susceptible to the disease. They require the full vaccine schedule to develop long-term immunity.
Are tetanus booster shots really needed?
Yes, getting tetanus booster shots throughout life is critical to maintain immunity. Immunity from both tetanus infection and vaccination begins to wane after a few years if not periodically boosted.
Some key reasons tetanus boosters are essential:
- Tetanus antibody levels start decreasing 2-3 years after getting vaccinated.
- Immunity may last up to about 10 years with an initial vaccine series.
- Booster shots extend antitoxin immunity to at least 20-30 years.
- Tetanus spores are present ubiquitously in the environment throughout life.
- Even minor skin wounds can allow entry of spores at any time.
Therefore, booster shots as recommended by the CDC vaccination schedule are vital. It ensures protective antitoxin antibody levels are maintained to defend against tetanus infection from potential wounds and injuries at any age.
Should antibiotics be given for tetanus-prone wounds?
Giving antibiotics after potential tetanus-prone injuries (like puncture wounds, burns, crush injuries etc.) can help prevent infection. Some key points:
- Antibiotics stop proliferation of tetanus spores before toxin production starts.
- Commonly used antibiotics for this purpose include metronidazole and penicillin.
- Wound cleaning and antibiotic use reduces risk of tetanus by about 50% for high-risk wounds.
- However, antibiotics do not provide full protection against tetanus on their own.
- Tetanus vaccine is still required after antibiotic therapy for wounds to boost immunity.
Therefore, prompt antibiotic use after potential tetanus-prone injuries, combined with tetanus booster vaccination, provides optimal protection against tetanus disease. Relying solely on antibiotics without also getting vaccinated leaves individuals insufficiently protected.
Conclusion
Tetanus is a severe, life-threatening illness caused by a potent neurotoxin produced by Clostridium tetani bacteria. The tetanus toxin irreversibly binds and blocks nerve cells, leading to painful muscle contractions. Once tetanus infection sets in, the body is unable to fight it off on its own because of the toxin’s ability to evade and suppress the immune response.
Tetanus can only be prevented through proper vaccination to develop antitoxin immunity before infection occurs. Tetanus vaccines provide long-lasting protection by generating neutralizing antibodies against the toxin. Getting the complete recommended vaccine schedule, plus booster shots every 10 years, is crucial for preventing tetanus disease throughout life. Antibiotic treatment of wounds potentially contaminated with tetanus can provide additional protection when combined with vaccination.
With modern ICU care and life support, tetanus disease is survivable but often leaves permanent residual damage. Recovery is prolonged. Having a tetanus infection does not produce immunity against future infections either. Therefore, maintaining up-to-date tetanus vaccination is the only reliable way to avoid this devastating illness through prompt toxin neutralization before it binds nerves irreversibly.