Paroxysmal sympathetic hyperactivity with disorders of consciousness
After someone has suffered a moderate-to-severe brain injury, they may develop paroxysmal sympathetic hyperactivity (PSH) syndrome, also called storming, with a set of symptoms that includes a fast heart rate, a fast breathing rate, fever, high blood pressure, sweating, and increased muscle tone.
What is PSH?
- Paroxysmal means that the symptoms occur or get worse during specific episodes throughout the day. PSH episodes are thought to be triggered by what is perceived by the body as pain.
- The sympathetic nervous system is responsible for the fight-or-flight response to danger and stress, causing a number of effects such as increased blood pressure, fast heart rate, and sweating.
- Hyperactivity means that there is an increased activity of the sympathetic response beyond what is healthy and normal.
How PSH develops
When a brain injury is severe enough, there is damage to a nerve pathway that goes from the upper brainstem down to the spinal cord that usually serves to calm down overactive areas of the spinal cord. Without this calming influence from the brainstem, there’s a pattern of overactivity in the spinal cord. A mildly painful sensation may then be processed as a severely painful sensation and the normal responses to pain such as increased heart rate and blood pressure get out of control. Eventually, as the spinal cord is overactive for long enough, it may stay in an elevated state, leading to even normally non-painful sensations causing an overactive response.
Duration of PSH episodes
Most cases of PSH pass within a few days. Patients in the more severe range and may experience the symptoms for weeks to months, requiring ongoing treatment.
Treatment
The treatment team will look at the symptoms and patterns of overactivity, as well as possible causes and the potential for discomfort and pain. Some causes of storming may include infections, unrecognized injuries, and other medical issues.
Symptomatic treatment
When no further treatable issues are found, symptomatic treatment for PSH will begin. Families and loved ones can help by carefully observing for causes that may trigger a storming episode, and make note any trends in the time of day and length of episodes.
Medications for PSH
A number of different medications may be used for PSH, including sedatives and medicines for pain, seizures, spasticity, and blood pressure.
Positioning and spasticity management
The treatment team may consider bed and wheelchair positioning and spasticity management techniques in an attempt to reduce the effects of severely increased muscle tone. If more conservative measures don’t initially succeed, they may consider an intrathecal baclofen pump placement. In that case, they may consider a trial injection of baclofen into the space around the spinal cord, done by a lumbar puncture; if the patient responds well to the trial, a pump placement by a neurosurgeon will be considered.
Role of caregiver in managing PSH
Caregivers can help by monitoring and documenting the storming episodes. They can also help to find the right positions that may help the person with the injury to relax, what environmental change can be made, and/or what comfort measures can be provided.