Opisthotonos, an uncontrolled flexing of muscles throughout your neck and back, is a symptom you can develop when there are major disruptions in how your brain works. It often is a sign of infections, toxins or poisons, or conditions that have toxic effects throughout your body. Many causes are preventable and treatable. The outlook usually depends on the underlying cause and how quickly you receive treatment.


What is opisthotonos?

Opisthotonos (pronounced “op-is-THOT-in-us”) is a reflex muscle movement. You might also see it spelled “opisthotonus.” It’s an uncontrolled flexing of muscles throughout your neck and back. It usually happens when a person is unconscious or unable to control muscle movements in their neck and back. It can happen because of infectious diseases, toxic events and other causes. It’s often a part of a larger reflex movement set called decerebrate posturing (which also includes jaw clenching and rigidly extending your legs and arms).

A person with opisthotonos (also sometimes called “opisthotonic posturing”) will have very strong muscle spasms causing their neck and back to hyperextend. If they’re on their back, that causes their back to lift off the ground and raise the trunk of their body (their chest and abdomen) toward the sky or ceiling. If on their side, their body posture may take on a crescent moon-like shape.

Opisthotonos isn’t common, but when it happens, it’s typically a sign of a serious illness or issue with your brain and the rest of your nervous system.


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Possible Causes

What are the most common causes of opisthotonos?

Opisthotonos indicates something very severe is affecting a person’s brain, causing muscles throughout their body to flex and spasm. Causes can include:


Toxins, poisons and drugs (medical and nonmedical)

Brain diseases or damage

Developmental or metabolic conditions

Care and Treatment

How is opisthotonos treated?

The treatment for opisthotonos depends strongly on what’s causing it. Many conditions and circumstances can cause or contribute to it, so the treatments can vary widely.

The conditions that cause opisthotonos are usually very severe, and people with opisthotonos are usually unconscious or in a coma. Because they’re unaware of what’s happening, they generally need a loved one or other authorized person to make medical decisions for them. In these cases, your loved one’s healthcare provider is the best person to tell you about possible treatments for their particular case.

What can I do at home to treat opisthotonos?

Opisthotonos is usually not a symptom you can treat at home. The only exception is if your provider tells you that it’s something you can manage outside a medical setting. If this is the case, your provider will guide you on how to care for opisthotonos and the condition(s) causing it.

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

Many of the conditions that cause opisthotonos are deadly when untreated. Others can cause severe brain damage. Opisthotonos is always a condition that needs medical attention unless you have a known, diagnosed condition, and your provider gives you specific guidance on when it doesn’t need medical care.


Can opisthotonos be prevented?

Opisthotonos has many possible causes. Most of these are unpredictable. The only causes that are preventable include:

  • Tetanus and rabies. To prevent these, stay vaccinated. If you have a possible exposure and aren’t sure of your vaccination status, see a healthcare provider as soon as possible to determine if you need a booster.
  • Concussions and traumatic brain injuries. Wearing helmets, safety restraints and other safety gear can reduce the risk or severity of concussions and brain injuries. Those can reduce the risk of developing opisthotonos.
  • Avoid nonmedical drug use. Take medications exactly as prescribed and tell your provider if you experience any side effects, especially uncontrolled muscle movements. Always avoid nonmedical drug use, especially substances like phencyclidine (PCP).
  • Avoid bites and stings. Wear appropriate clothing and protective gear (especially gloves) when gardening or doing other activities that might disturb spiders or scorpions. That can avoid venom-related opisthotonos.

There may be other ways to prevent opisthotonos or manage conditions that can cause it. To learn if this is possible, talk to your (or your loved one’s) healthcare provider about what you can do.

A note from Cleveland Clinic

Opisthotonos is an uncommon but serious symptom of conditions and events that severely disrupt how your brain works. Many possible causes of opisthotonos are preventable, and some are treatable and reversible. The outlook depends on the underlying cause. If a loved one has what looks like opisthotonos for an unknown reason, they need immediate medical attention. Prompt care can make a big difference in the outcome.

Medically Reviewed

Last reviewed on 10/01/2023.

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