Opisthotonos is a condition of abnormal posturing that involves rigidity and severe arching of the back, with the head thrown backward. If a person with opisthotonos were laid on his or her back, only the back of the head and the heels would touch the supporting surface.

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.

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.

• Achondroplastic dwarfism (occasionally)
• Arnold-Chiari syndrome
• Brain tumor
• Gaucher disease
• Glutaric aciduria and organic acidemias
• Krabbe Disease
• Meningitis
• Seizures
• Severe head injury
• Stiff-person syndrome
• Subarachnoid hemorrhage
• Tetanus

Drugs, particularly phenothiazines and other antipsychotic medications, can cause a side effect known as acute dystonic reaction. Opisthotonos may be part of this reaction.

Hospital care is required for a person who develops opisthotonos.

Go to the emergency room or see your doctor immediately if this symptom occurs. Typically, however, 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