Understanding Tetanus — the Basics

Medically Reviewed by Jabeen Begum, MD on August 30, 2024
7 min read

Tetanus (lockjaw) is a dangerous nerve ailment caused by the toxin of a common bacteria, Clostridium tetani. You can find these bacterial spores everywhere, but mostly in soil. They're also found in animal poop, house dust, the human colon, and on the surfaces of rusty tools such as nails. The spores can survive for years because they resist heat and antiseptics. The condition isn't spread from person to person. 

If the spores enter a wound that penetrates the skin and extends deeper than oxygen can reach, they germinate and produce a toxin that enters the bloodstream. This toxin, tetanospasmin, ranks with botulism toxin as one of the most dangerous. It's absorbed from the blood by the outermost nerves and moves toward the spine.

Once there, it begins to short-circuit nerve signals and block the relaxation of muscles. This results in a tightening of your muscles and the locking of your jaw, so you can't open your mouth or swallow. Once tetanus has spread through your body, it leads to death in 10%-20% of cases, even in a modern hospital setting.

Tetanus is rare in developed countries because most babies are vaccinated against it. But newborn babies and pregnant mothers in some developing countries, who haven't been immunized, are at risk. 

Even if you were vaccinated as a baby, the immunity wanes over time, so you should get a booster every 10 years or when you get a bad cut, wound, or burn.

You get tetanus when Clostridium tetani spores enter your body through broken skin and grow into bacteria. This can happen in several different ways, including cuts, wounds, burns, or animal and insect bites.

Wounds, burns, and cuts

You can get tetanus from:

  • Puncture wounds caused by stepping on a nail or needle, or from a wood splinter
  • Wounds contaminated with dirt, poop, or spit
  • Injuries with dead tissue, such as burns and frostbite
  • Contaminated needles from intravenous drug use
  • Contaminated surgical instruments
  • Chronic (ongoing) sores and infections

Although most people associate getting tetanus with stepping on a rusty nail, it's not the rust that gives you tetanus. The bacteria is found mostly in soil and animal manure, so it tends to exist in the same types of areas where you'd find rusty nails and old farming equipment.

Animal bites

A less common way of getting tetanus is from an animal bite. The vast majority of animal bites in the U.S. are from dogs (85%-90%). The rest come from cats (5%-10%) and rodents (2%-3%). If you get an infection from an animal bite, your skin will swell and turn red, and you'll have intense pain 12-24 hours after the bite.

You can also get tetanus from an insect bite, including bites from certain flies and spiders, though this is rare. Mosquitoes are unlikely to spread tetanus.

Regardless of the cause, you're much more likely to get tetanus from a wound or bite if you haven't had the tetanus vaccine, or the one you got isn't up to date. Other high-risk groups include people who:

  • Inject street drugs in their veins
  • Have weakened immune systems (for instance from taking cancer-fighting drugs)
  • Are diabetic
  • Are over 70 (because of waning vaccination immunity)

 

 

 

The first sign of tetanus is usually a tightening of the jaw muscles, called lockjaw, so you can't open your mouth. Other symptoms can include:

  • Trouble swallowing
  • Sudden muscle spams in the arms, legs, back, and stomach
  • Painful muscle stiffness all over the body
  • Seizures 
  • Headache
  • Fever and sweating
  • Changes in blood pressure and heart rate

Tetanus muscle spasms

Muscle spasms can be triggered by minor sounds, touch, or light. When this happens, your neck and back arch, your legs become stiff, your arms draw up to your body and your fists clench. You may have trouble breathing because of stiffness in your neck or stomach. These spasms last several minutes.

Tetanus symptoms timeline

Symptoms of tetanus can appear anywhere between 3 and 21 days after infection. The average is 8 days. The most common type of tetanus is generalized tetanus. Here, the symptoms start at the jaw and progress down the body over 2 weeks.

It starts with a lockjaw and a contraction of the facial muscles, giving you a permanent "smile." Then comes a stiffening of the neck, trouble swallowing, and rigidity in the stomach, arms, and legs. 

Spasms can last up to 4 weeks. Full recovery can take months.

If you have any of these symptoms, be sure to get medical attention.

Severe tetanus symptoms

As the disease progresses, you might also have the following symptoms:

  • High or low blood pressure
  • Fast heart rate
  • Fever
  • Extreme sweating

You might also have the following complications:

  • Tightening of the vocal cords (laryngospasm)
  • Broken bones
  • Blockage in the lungs from a blood clot (pulmonary embolism)
  • Lung infection from inhaling spit or vomit (aspiration pneumonia)
  • Difficulty breathing

Tetanus can even lead to death in some cases.

Neonatal tetanus

This is a form of generalized tetanus that affects newborn babies. They get it from their unvaccinated mothers or from contaminated instruments used when cutting their umbilical cord. Those who're infected have muscle spasms, rigid jaws, and trouble sucking or breastfeeding. They may cry a lot. In the long term, they could have problems with walking, talking, and brain development.

In developing countries, about 25,000 newborns died from neonatal tetanus in 2018. This is a 97% decline since 1988, mostly because of large-scale immunization.

 

 

There isn't a lab test for tetanus. Your doctor will make the diagnosis by looking at your symptoms and asking about your medical and vaccination history. Your doctor may order lab tests if they need to check that your symptoms aren't due to some other disease.

Treatment for tetanus usually requires hospital care and the following:

  • Tetanus immune globulin (medication)
  • Intensive wound care
  • Drugs to control muscle spasms
  • Antibiotics
  • Tetanus vaccination

Tetanus immune globulin

This medicine can treat or prevent tetanus. It's made from blood and gives your body the antibodies it needs to neutralize the tetanus toxin until your immune system can produce its own antibodies. Treatment involves giving one injection into a muscle.

Tetanus immune globulin only works on toxins that haven't yet attacked nerve tissues. So, if you visit the doctor about a serious wound and your tetanus vaccine was not up to date, they would give you a tetanus booster but may also give you tetanus immune globulin to protect you until the vaccine starts working (usually about 2 weeks).

Medicine for tetanus

In addition to tetanus immune globulin, you'll usually get antibiotics such as metronidazole or penicillin to kill the C. tetani bacteria.

To control muscle spasms, you may be given a sedative such as diazepam.

To manage tetanus complications, such as fluctuating blood pressure, rapid heartbeat, and hypothermia, you may get magnesium along with a sedative.

Your hospital team will make sure you can breathe properly and that a feeding tube provides high-calorie nutrition since muscle contractions use up a lot of energy. They'll also keep loud sounds, touch, and bright light to a minimum so as not to trigger any spasms. You'll probably need physical therapy after you're feeling better because the spasms affect your muscles.

Wound care

Wound care is an essential part of tetanus treatment. Tetanus wounds need to be cleaned to remove dirt or foreign objects and debrided, meaning that dead tissue must be removed. Otherwise, the bacteria will continue to spread in your body.

Having had tetanus doesn't give you immunity from the condition. Your doctor will give you a vaccination so you don't get tetanus again. Although most people get a tetanus shot as babies as part of the DTaP (diphtheria, tetanus, pertussis, or whooping cough) vaccine, everyone should:

  • Get a tetanus booster shot every 10 years
  • Get a tetanus booster if they have a contaminated wound and it's 5 years or more since the last shot (or they can't remember when the last shot was)

Tetanus, aka lockjaw, is a very serious condition where your jaw and eventually other body parts stiffen as your muscles contract. You can have muscle spasms and seizures. You can get tetanus from any open wound that's contaminated with dirt, feces, or dead tissue (such as a burn). Treatment involves hospitalization, taking different drugs, and having your wound properly cleaned and cared for. Tetanus is rarely seen in the U.S., thanks to routine childhood immunization. If you're an adult, you should get a tetanus booster every 10 years.

Can tetanus heal on its own?

Eventually, yes. But without treatment, 1in 4 infected people (25%) will die. With treatment, less than 15% will die.

When is it too late to get a tetanus shot after injury?

Tetanus symptoms take an average of 8 days to show up, so you should try to get your shot as soon as possible, preferably no more than 72 hours after injury. If you're past that, still go and see your doctor.

At what age is the tetanus vaccine given?

The World Health Organization recommends three doses starting at 6 weeks of age, with 4 weeks between each of the follow-up doses. Three boosters should be given at the ages of 2, 4-7, and 9-15. Adults should get a booster every 10 years.

Can you get tetanus from a small cut?

Yes, from some kinds of small cuts. If your cut is contaminated with soil, animal manure, or dust (and it wasn't cleaned right away), or it involves a wood splinter or thorn, you might be at risk for tetanus if your vaccines aren't up to date. Clean your cut immediately and cover it with a bandage to prevent bacteria from getting in. If you can't get your cut properly clean, leave it open and get medical attention.