Tetanus (Lockjaw)

How tetanus works

Clostridium tetani forms hardy spores that survive for years in soil, dust and manure. When spores get into a wound with little oxygen, such as a deep puncture or dead tissue, they become active and release a toxin called tetanospasmin. The toxin travels along nerves to the spinal cord and brain stem. There it blocks the nerve signals that normally tell muscles to relax. Without that brake, muscles contract continuously and go into violent spasms.

The infection itself stays in the wound. It is the toxin that causes the illness. Tetanus is not contagious, and having it does not make you immune, so survivors still need vaccination.

Symptoms of tetanus

Symptoms usually start 3 to 21 days after the injury, most often around 8 days. A shorter time usually means more severe disease.

First signs

• cramping, stiffness or aching of the jaw muscles, and difficulty opening the mouth (trismus, or lockjaw)
• a fixed, tense facial expression with raised eyebrows and a grimace, called risus sardonicus
• stiff neck and difficulty swallowing
• restlessness and irritability

As it progresses

• stiffness of the back, belly and limb muscles
• painful, sudden muscle spasms lasting seconds to minutes, triggered by noise, light, touch or even a draft
• arching of the back (opisthotonus) in severe spasms
• spasms of the throat and breathing muscles, which can stop breathing
• fever, sweating, high blood pressure and a fast heart rate as the toxin affects the autonomic nervous system

The person usually stays fully conscious through the spasms, which are extremely painful.

Types of tetanus

How do you get tetanus?

Tetanus enters through broken skin. Higher-risk wounds include:

• puncture wounds, such as stepping on a nail or a splinter
• wounds contaminated with soil, dirt, feces or saliva
• crush injuries and wounds with dead tissue
• burns and frostbite
• animal bites and human bites
• compound fractures, where bone breaks the skin
• injection drug use, especially with contaminated needles or "skin popping"
• body piercing and tattoos done with unclean equipment
• chronic wounds such as diabetic foot ulcers, and any wound infection with dead tissue

Rusty metal is not itself the cause. Rust just tends to be on objects that have been outdoors in soil and dust. In the US, most cases now occur in adults who were never vaccinated or whose boosters lapsed, especially older adults and people with diabetes.

Diagnosis

There is no blood test that confirms tetanus. Doctors diagnose it from the symptoms, examination and a history of a wound and uncertain vaccination. A simple bedside test is the "spatula test": touching the back of the throat with a tongue depressor causes the jaw to clamp down instead of gagging. Doctors may run tests to rule out conditions that look similar, such as meningitis, strychnine poisoning, low calcium, drug reactions, rabies and dental abscesses causing jaw stiffness.

Treatment

Tetanus is treated in the hospital, usually in intensive care, often for several weeks.

• Tetanus immune globulin (TIG): antibodies that neutralize toxin still circulating, before it binds to nerves. Toxin already in the nerves cannot be reversed, so recovery depends on nerves regrowing their endings.
• Wound care: cleaning and removing dead tissue to stop more toxin production.
• Antibiotics: usually metronidazole, to kill remaining bacteria.
• Controlling spasms: sedatives such as benzodiazepines, magnesium, and in severe cases muscle-paralyzing drugs.
• Breathing support: a breathing tube or tracheostomy and a ventilator if spasms affect breathing.
• A quiet, dark room to reduce triggers for spasms.
• Vaccination: a course of tetanus vaccine starts during recovery, because the disease does not give immunity.

Recovery can take months. Muscle spasms usually ease over 2 to 4 weeks, and stiffness can last longer.

Complications

• spasm of the vocal cords, blocking breathing
• pneumonia, especially from inhaling secretions
• broken bones, including the spine, from violent spasms
• blood clots in the lungs from long bed rest
• dangerous swings in blood pressure and heart rhythm

Preventing tetanus: vaccines and wound care

Routine vaccination in the US

• Children: 5 doses of DTaP at 2, 4 and 6 months, 15 to 18 months, and 4 to 6 years.
• Preteens: 1 dose of Tdap at age 11 to 12.
• Adults: a Td or Tdap booster every 10 years.
• Pregnancy: Tdap during every pregnancy, ideally between 27 and 36 weeks, which also protects the newborn from neonatal tetanus and whooping cough.

Do I need a tetanus shot after a wound?

Clean every wound promptly with soap and running water, remove dirt, and see a doctor for deep, dirty or puncture wounds.

Frequently asked questions

What are the first signs of tetanus?

The first signs are usually stiffness or cramping of the jaw muscles and difficulty opening the mouth, followed by a stiff neck, trouble swallowing and stiffness of the belly muscles. They typically start about a week after a wound, but can appear anywhere from 3 days to 3 weeks later.

How soon after a wound do I need a tetanus shot?

As soon as possible, ideally within 48 hours, if your vaccines are not up to date for that type of wound. For a dirty or deep wound, you need a booster if your last dose was more than 5 years ago. Unvaccinated people may also need tetanus immune globulin.

Can you get tetanus from rusty metal?

You get tetanus from the bacteria's spores, not from rust. Rusty objects are often outdoors in soil and dust that carry spores, and a nail causes the kind of deep puncture where the bacteria thrive. Any dirty puncture wound carries the same risk.

Is tetanus curable?

There is no medicine that reverses toxin already bound to nerves. Treatment neutralizes remaining toxin, clears the bacteria and supports the body, especially breathing, while the nerves recover over weeks to months. With intensive care, most people survive and recover fully.

Is tetanus contagious?

No. Tetanus does not spread from person to person. You can only get it when spores enter a wound. Having had tetanus does not make you immune, so vaccination is still needed afterward.