As tetanus vaccination rates decline, doctors worry about rising case numbers

NBC NEWS – Every doctor wants to see a smile on a patient’s face, but there is one that no doctor ever wants to see: risus sardonicus, sometimes known as the sardonic grin or the devil’s smile, the cruel mark of a tetanus infection.

After decades of success against tetanus in the U.S., there are troubling signs that the deadly bacterial infection could make a comeback, a fallout from the drop in vaccination combined with a rise in climate change-related natural disasters that can increase the risk of exposure.

In 1948, when the tetanus vaccine was first combined with diphtheria and pertussis, 601 cases of tetanus were reported in the U.S. In recent years, that has dropped to about 15 to 28 annual cases.

In 2024, however, there were 32 cases. This year, there have been at least 37 confirmed cases, the most in over a decade.

An NBC News/Stanford University investigation has found widespread declines in kindergarten vaccination against tetanus.

In states that provided data back to 2019, more than 75% of counties and jurisdictions across the U.S. have seen downward trends in young children getting the diphtheria-tetanus-pertussis (DTaP) series of shots. The vaccine is first given to babies at 2 months.

Because tetanus isn’t spread from person to person, there isn’t a herd immunity threshold, but reductions in vaccination rates leave more people vulnerable to the disease.

Doctors are worried about even a small uptick in the terrible infection, often called lockjaw. Symptoms, which can take three to 21 days to appear, include muscle spasms that make it difficult to breathe.

As the infection takes hold, a patient’s jaw clenches, forcing the face into what appears to be a wide smile, and the back muscles contort into a painful arch …

READ MORE [free to read] | What does risus sardonicus look like? [VIEW DISCRETION]

What is risus sardonicus?

CLEVELAND CLINIC – Risus sardonicus (rye-sus sar-dan-uh-kes) is when the muscles in your face tighten, forcing a big, open-mouth smile and raised eyebrows. Some people describe it as a sneer. It’s a type of painful, involuntary muscle spasm.

But it isn’t like spasms that occur in other parts of your body. Those can occur due to dehydration, overuse or sitting too much. Instead, risus sardonicus usually happens from a certain type of bacterial infection. It can also result from particular genetic conditions and exposure to certain poisons.

“Risus” is Latin for “laugh.” “Sardonicus” comes from the Greek word “sardónios,” which means a bitter or scornful laugh or smile. Other names for risus sardonicus include:

• Rictus grimace
• Rictus grin
• Tetanus smile

What causes risus sardonicus?

The most common cause of risus sardonicus is tetanus. Tetanus is a bacterial infection. It causes muscle spasms, especially in your head, neck and face.

Other possible risus sardonicus causes include:

• Strychnine poisoning: Strychnine is a bitter, odorless, white powder. It’s mostly used in rat poisons. In rare cases, cocaine, heroin and LSD (acid) may contain strychnine. It affects the nerve signals in your muscles and causes severe spasms.
• Wilson disease: This is a rare condition that some people have at birth. It causes copper to build up in your body, especially in your brain and liver. Not everyone who has Wilson disease experiences the same symptoms. But some experience muscle stiffness, including risus sardonicus.

How is it treated?

Risus sardonicus treatment depends on the cause.

Tetanus treatment generally includes medications, such as:

• Antibiotics like metronidazole and penicillin G
• Tetanus antitoxin (human tetanus immunoglobulin)
• Tetanus shot (tetanus toxoid)

Healthcare providers may recommend muscle relaxers to help reduce spasms. You may also need benzodiazepines (benzos) to slow down your nervous system.

If you have strychnine poisoning, it’s important to get it out of your system as quickly as possible. Treatment usually includes:

• Antiseizure medications and antispasmodics to treat muscle spasms or shaking
• IV fluids to help flush out strychnine
• Lowering a high body temperature

If Wilson disease causes risus sardonicus, providers may recommend botulinum toxin (Botox®) injections. They’ll inject Botox around your mouth and eyebrows.

What are the possible complications or risks of not treating it?

The causes of risus sardonicus are life-threatening without treatment. Get help as soon as possible if your face locks into a big smile and raised eyebrows.

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