Paroxysmal Sympathetic Hyperactivity: Development of a Pediatric Clinical Practice Guideline

Paroxysmal sympathetic hyperactivity (PSH) is a syndrome associated with antecedent brain injury characterized by episodes of sympathetic overdrive, primarily manifested as episodic vital sign instability (tachycardia, tachypnea, hyperthermia, hypertension) with increased neuromuscular tone and other clinical manifestations, such as diaphoresis and mydriasis.¹ The preeminent physician Walter Penfield initially (and erroneously) described similar phenomena as “mesencephalic seizures” in patients after a traumatic brain injury (TBI). Since that time, awareness of PSH persisted without clear diagnostic criteria and under as many as 31 separate labels, such as dysautonomia, paroxysmal autonomic instability, and thalamic storming.^2–4 A consensus group in 2014 established clear terminology and a definition for PSH, with a clinical feature scale (CFS) and diagnosis likelihood tool (DLT) to aid in diagnosis.^1,5 Although helpful, this consensus statement omitted diagnostic terminology for the pediatric population and did not recommend specific treatment strategies.