It is a condition in which the body is held in an abnormal position , the person is usually rigid and arches the back with the head thrown backwards . if the patient lies on his or her back only the back of the head and the heels touch the supporting surface .Opisthotonos is much more common in infants than in adults , it is also more exaggerated in infants and children because of their less mature nervous system .
Causes : Opisthotonos may occur in infants with meningitis , it may also occur as a sign of reduced brain function or injury of the nervous system
Other causes : Tetanus , subarachnoid hemorrhage , strychnine poisoning , Archnold chiari syndrome , Brain tumours , seizures , severe electrolyte imbalance . You should ask about the onset and what other symptoms come before or with this abnormal posturing ( such as fever , stiff neck and headache ), and if there is any recent history of illness .
Investigations : Blood and urine tests , CSF examination including culture
CTscan of the brain ,MRI, serum electrolytes