Alternative names: Back arching; Abnormal posturing — opisthotonos; Decerebrate posture — opisthotonos
Definition: Opisthotonos is a condition in which a person holds their body in an abnormal position. The person is usually rigid and arches their back, with their head thrown backward. If a person with opisthotonos lies on their back, only the back of their head and heels touch the surface they are on.
Opisthotonos is much more common in infants and children than in adults. It is also more extreme in infants and children because of their less mature nervous systems.
Opisthotonos may occur in infants with meningitis. This is an infection of the meninges, the membranes that cover the brain and spinal cord. Opisthotonos may also occur as a sign of reduced brain function or injury to the nervous system.
Other causes may include:
- Arnold-Chiari syndrome, a problem with the structure of the brain
- Brain tumour
- Cerebral palsy
- Gaucher disease, which causes a buildup of fatty tissue in certain organs
- Growth hormone deficiency (occasionally)
- Forms of chemical poisoning called glutaric aciduria and organic acidemias
- Krabbe disease, which destroys the coating of nerves in the central nervous system
- Maple syrup urine disease, a disorder in which the body can’t break down certain parts of proteins
- Severe electrolyte imbalance
- Traumatic brain injury
- Stiff-person syndrome (a condition that makes a person rigid and have spasms)
- Bleeding in the brain
Some antipsychotic medicines can cause a side effect called acute dystonic reaction. Opisthotonos may be part of this reaction.
In rare cases, infants born to women who drink large amounts of alcohol during pregnancy may have opisthotonus due to alcohol withdrawal.
A person who develops opisthotonos will need to be cared for in a hospital.
When to Contact a Medical Professional
Go to the emergency room or call your local emergency number (such as 911) if symptoms of opisthotonos occur. Typically, opisthotonos is a symptom of other conditions that are serious enough for a person to seek medical attention.
What to Expect at Your Office Visit
This condition will be evaluated in a hospital, and emergency measures may be taken.
The health care provider will perform a physical examination and ask about symptoms to look for the cause of opisthotonos
Questions may include:
- When did the symptoms start?
- Is the body positioning always the same?
- What other symptoms came before or with the abnormal positioning (such as fever, stiff neck, or headache)?
- Is there any recent history of illness?
The physical examination will include a complete checkup of the nervous system.
Tests may include:
- Blood and urine tests
- Cerebrospinal fluid (CSF) culture and cell counts
- CT scan of the head
- Electrolyte analysis
- Lumbar puncture (spinal tap)
- MRI of the brain
Treatment will depend on the cause. For example, if meningitis is the cause, medicines may be given.
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