Neurostorming is a complex neurological condition that can emerge during recovery from a severe brain injury, representing a period of intense, uncontrolled body responses. This phenomenon is formally known as Paroxysmal Sympathetic Hyperactivity (PSH). It involves a sudden, exaggerated activation of the body’s “fight or flight” system, which leads to a cascade of physical reactions. The condition is characterized by episodes that come and go, rather than a constant state of arousal.
The Types of Injuries That Trigger Neurostorming
Neurostorming is most frequently observed in patients who have suffered a severe traumatic brain injury (TBI). It is estimated to occur in a significant number of individuals who are in a comatose state following such trauma, sometimes affecting up to a third of severe TBI patients. The severity of the initial injury appears to increase the likelihood of developing these episodes.
Beyond trauma, several other types of catastrophic brain events can also trigger this response. These include anoxic brain injury, which results from a lack of oxygen to the brain, such as following cardiac arrest or drowning. Intracerebral hemorrhage, a type of stroke caused by bleeding within the brain tissue, and hydrocephalus, a buildup of fluid in the brain, are also recognized causes.
Recognizing the Physical Signs of a Storm
Recognizing a neurostorming episode involves identifying a cluster of specific physical signs that occur episodically. One common indicator is hyperthermia, or a high fever, often exceeding 101°F (38.5°C). This is frequently accompanied by profuse sweating, medically known as diaphoresis.
The cardiovascular system shows signs of stress during these episodes. Patients often experience tachycardia, a rapid heart rate sometimes measured over 130 beats per minute. Simultaneously, blood pressure becomes elevated, a condition called hypertension, and rapid breathing (tachypnea) is common.
A visible sign of a storm is the presence of abnormal muscle posturing and rigidity, sometimes referred to as dystonia. This manifests as stiffened limbs and an unusual body position, such as an arched neck and spine. These symptoms appear in cycles that can last anywhere from a few minutes to several hours.
The Underlying Mechanism
The physical signs of neurostorming stem from a loss of control over the Autonomic Nervous System (ANS), which regulates involuntary body functions like heart rate and temperature. The problem involves the excessive, uncontrolled firing of the Sympathetic Nervous System (SNS), the division responsible for the “fight or flight” response. When the brain is severely injured, the regulatory balance between the sympathetic and parasympathetic nervous systems is lost.
The prevailing explanation is the “disconnection theory,” which suggests that the injury damages the brain’s inhibitory pathways. Normally, higher brain centers, such as the cerebral cortex, send signals to the lower brainstem to suppress the sympathetic response. When these inhibitory pathways are damaged, the lower centers, like the hypothalamus, are released from control.
This damage results in the lower brainstem centers generating an excessive sympathetic tone without moderating influence. The subsequent surge of hormones like adrenaline causes the body to enter a state of heightened alert. This unwarranted activation of the stress response manifests as the physical storming episodes.
Controlling the Episodes
The management of neurostorming focuses on reducing the frequency and intensity of the body’s overreaction to allow the brain to heal. Medical intervention involves pharmacological strategies aimed at dampening the excessive sympathetic activity. Medications are used to address specific symptoms, such as controlling high blood pressure and heart rate.
Beta-blockers, such as propranolol, are commonly used to stabilize heart rate and blood pressure by blocking adrenaline’s effects. Other agents like alpha-2 agonists, such as clonidine, may be employed to further reduce sympathetic outflow from the central nervous system. Sedation and analgesic medications are also used to provide comfort and reduce the body’s overall stress response.
Environmental management is also important, as external factors can often trigger a storm. Simple sensory inputs, like loud alarms, bright lights, or repositioning the patient, can initiate an episode. Care teams work to create a low-stimulation environment, using quiet rooms and soft lighting to minimize potential triggers.