Opisthotonos is a condition in which the body is held in an abnormal posture. It usually involves rigidity and severe arching of the back, with the head thrown backward. If a person with opisthotonos lays on his or her back, only the back of the head and the heels would touch the supporting surface.

See: Abnormal posturing

Opisthotonos is much more common in infants and children than in adults. It is also more exaggerated in infants and children because of their less mature nervous systems.

Opisthotonos may occur in infants with meningitis, where it is a sign of irritation of the membranes surrounding the brain and spinal cord (meninges).

It may also occur as a sign of depressed brain function or injury to the nervous system.

Other causes may include:

• Brain tumor
• Growth hormone deficiency (occasionally)
• Glutaric aciduria and organic acidemias (forms of chemical poisoning)
• Krabbe Disease (disorder of metabolism)
• Meningitis
• Seizures
• Severe head injury
• Stiff-person syndrome (a condition that involves worsening rigidity and spasms)
• Subarachnoid hemorrhage (bleeding in the brain)
• Tetanus
• Arnold-Chiari syndrome (a brain structure problem)
• Gaucher disease (disorder of metabolism)

Drugs, particularly phenothiazines and other antipsychotic medications, can cause a side effect known as 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.

Hospital care is required for a person who develops opisthotonos.

Go to the emergency room or call your local emergency number (such as 911) if this symptom occurs. Typically opisthotonos is a symptom that follows late in the course of other conditions, which are serious enough that medical attention will likely have already been sought.

This condition will be evaluated in a hospital setting. Emergency measures will be taken as appropriate.

The medical history will be obtained, and a physical examination will be performed.

Medical history questions documenting opisthotonos in detail may include:

• When did this behavior start?
• Is it always the same type of posturing?
• What other symptoms preceded or accompanied the abnormal posturing (particularly fever, stiff neck, headache, but also any others)?
• Is there any significant medical history (such as a recent illness)?

The physical examination will include a complete assessment of the nervous system.

The cause of the opisthotonos will be suggested by the history and physical examination. Diagnostic tests may include:

• Lumbar puncture and analysis of the cerebrospinal fluid (CSF culture, CSF cell counts, and similar studies), electrolyte analysis
• CT scan of the head
• MRI of the head
• Blood and urine tests

Chiriboga CA. HIV, fetal alcohol and drug effects, and the battered child. In: Rowland LP, ed. Merritt’s Neurology. 11th ed. Baltimore, Md: Lippincott Williams & Wilkins; 2005:chap 168.