Opisthotonus is a type of abnormal posture where the back becomes extremely arched due to muscle spasms.

The condition is usually a sign of serious brain conditions, such as meningitis, tetanus, and trauma.

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A painting by Sir Charles Bell from 1809 of opisthotonos.

Opisthotonos is a specific abnormal posture associated with conditions and injuries that impair brain and muscle function. The characteristic symptoms of opisthotonos are a severely arched or curved spine and head and heels that tilt backward.

Though relatively rare, the condition is usually a symptom of severe neurological conditions that are life threatening and require medical care.

Opisthotonos mostly impacts infants and young children, though it can occasionally affect adults.

Opisthotonos causes the back to become extremely rigid and curved or arched. The heels and head usually bend or flex backward as far as possible in response.

If someone is on their back, they will arch upwards, forming an n-shape. In this position, the back usually lifts the back off floor or mattress to some extent.

The arms also bend towards the body. In some cases, the head and lower body may be the only part of the body to keep in contact with the ground.

If someone is on lying on their stomach when opisthotonos occurs, they will bend inward creating a u-shape. The legs and arms usually reach backward and upward.

If the condition occurs when someone is lying on their side, the arching will form a c-shape. The person's knees bend, and their arms either bend in or extend straight out. In this position, the backward arching of the neck may be more noticeable or severe.

Aside from these postural symptoms, the signs of opisthotonos vary depending on the cause.

People should seek medical attention anytime severe muscle spasms occur. Opisthotonos is considered life-threatening and is associated with serious health complications.

Symptoms that may accompany opisthotonos and require emergency care include:

  • trouble breathing
  • difficulty swallowing
  • rapid heart rate
  • a bluish tone in the fingers and toes
  • stiff jaw, neck, and abdominal muscles
  • extreme pain and soreness in the neck, shoulders, and muscles that surround the spine
  • high fever
  • convulsions
  • uncontrollable vomiting
  • reduced alertness or response time
  • dilated pupils or vision problems
  • extreme and unexplainable exhaustion

Because the condition mostly affects infants and young children, these symptoms may be harder to pinpoint. Uncontrollable, persistent crying with muscle spasms may be a sign of opisthotonos.

Infants may sleep more than usual but are restless, continually waking to adjust or find a more comfortable position.

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The tetanus bacteria may damage the nervous system and brain tissue.

Meningitis: When an infection causes inflammation of the tissues that surround the brain and spinal chord. The majority of cases in the United States are viral, but bacteria and fungi can also cause the condition.

Tetanus: Caused by toxins produced by the bacteria Clostridium tetani, which damage the nervous system and brain tissue. Tetanus is often called lockjaw because its most common symptoms are a locked jaw, stiff neck, and trouble swallowing.

Poisonings or overdoses: Young children are at a greater risk of accidental poisoning. Consuming strychnine, a chemical found in rodent poisons, pesticides, and insecticides can also cause the condition.

Cerebral palsy: When brain damage that occurs during fetal development causes a range of symptoms related to muscle dysfunction.

Phenothiazines: These are drugs commonly used to treat certain mental health conditions, such as schizophrenia. Opisthotonos is a rare side effect, and symptoms usually go away once the person has stopped taking the drugs.

Krabbe disease: An inherited condition that mostly impacts infants, young children, and young adults. Krabbe disease causes loss of muscle control and seizures that do not respond to treatment and can lead to premature death.

Gaucher disease: Fat-filled cells build up in organs, especially the liver and spleen, causing them to swell; fat cells also affect the bone marrow, causing bone pain. One severe form of Gaucher disease can cause opisthotonus in infants, but this is rare.

Bilirubin encephalopathy, or kernicterus: A brain dysfunction that can potentially cause irreversible brain damage. Newborns and adults with pre-existing liver conditions have a higher risk of bilirubin encephalopathy.

Infant alcohol withdrawal: This occurs when a pregnant woman drinks excessive amounts of alcohol while pregnant. Infant alcohol withdrawal can cause reduced or uncontrollable muscle function. It rarely causes opisthotonos, however.

Other causes include conditions that involve increased cranial pressure, such as:

  • Brain hemorrhage or bleeding: This occurs when injury, disease, congenital disabilities, or blood vessels in the brain rupture, causing blood to accumulate and put pressure on brain tissues.
  • Hydrocephalus: Congenital disability, injury, or disease cause cerebral spinal fluid (CSF) to accumulate, putting pressure on the brain.
  • Subarachnoid hemorrhage: This happens when bleeding occurs between the brain and the tissues surrounding it.
  • Brain tumor: An abnormal, often uncontrollable cellular growth that can put pressure on the brain tissues and disrupt nerve function.
  • Chiari malformation: Part of the lower brain pushes out through the spinal canal, increasing pressure on the spine, brain, and often interfering with fluid flow causing hydrocephalus. Only some types of Chiari malformation do this.

Doctors diagnose opisthotonos by observing the posture when it is happening. Doctors are usually more focused on identifying and quickly treating the underlying cause than confirming opisthotonos.

Tests used to diagnosis the causes of opisthotonos include:

  • complete blood and urine tests
  • magnetic resonance imagining (MRI) of the brain
  • electrolyte tests
  • lumbar puncture (spinal tap)
  • cerebrospinal fluid (CSF) culture test
  • computed tomography (CT) scan

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With bacteria-based infections, antibiotics may help to treat the underlying cause of opisthotonos.

Treatment options depend on the underlying cause of opisthotonos. Commonly used treatment plans include:

  • Antibiotics for bacterial based infections, such as meningitis and tetanus. Antibiotics are also prescribed to prevent infection or further bacterial infections after surgery.
  • Over-the-counter pain medications, increased fluid intake, and rest are recommended for most cases, especially viral infections, such as meningitis.
  • Intravenous fluids are usually given in severe cases and to counteract bronchodilator overdoses.
  • Surgery is often necessary in cases of trauma, bleeding, and Chiari malformation to reduce pressure on the brain.
  • Antitoxin injections or medications are often given to those with tetanus to limit excess tissue damage associated with severe infection.
  • Ventilator and oxygen may be used when breathing is limited, labored, or difficult.

There are vaccines that offer protection against some of the conditions that cause opisthotonos, such as tetanus and some types of bacterial meningitis.

Other ways to reduce the chances of developing opisthotonos:

  • washing hands frequently
  • cleaning bathroom and kitchen surfaces regularly
  • avoiding contact with those who have infectious conditions
  • monitoring high fevers carefully, especially in infants and young children
  • quickly identifying and treating brain injuries