Traumatic brain injury
The number of events that can lead to the development of PSH symptoms is many. The exact pathways or causes for the development of the syndrome are not known. Traumatic brain injury, hypoxia, stroke, anti-NMDA receptor encephalitis (although further associations are being explored), injury of the spinal cord, and many other forms of brain injury can cause onset of PSH. Even more obscure diseases such as intracranial tuberculoma have been seen to cause onset of paroxysmal sympathetic hyperactivity. It is observed that these injuries lead to the development of PSH or are seen in conjunction with PSH, but the pathophysiology behind these diseases and the syndrome is not well understood.