Paroxysmal Sympathetic Hyperactivity in Pediatric Acquired Brain Injury: An Under-Recognized Entity.

Paroxysmal sympathetic hyperactivity (PSH) is a less-known neurologic emergency that can be life-threatening. It is a form of extreme autonomic dysregulation leading to multiple episodes of sympathetic hyperactivity. The pathogenesis of this interesting entity is yet to be fully understood. It presents as unexplained tachycardia, hypertension, and sometimes hyperthermia. Poor awareness of this fact leads to unnecessary workup to look for the cause of fever and interventions such as change of antibiotics. If it is not treated adequately, it can even cause complications like arrhythmias that can be fatal at times. PSH secondary to acquired brain injury is better known in adults, but there are scarce reports in children. We describe six cases of PSH in children with acquired brain injury - four secondary to traumatic brain injury and two secondary to neurologic infection (one with bacterial meningitis and the other one with viral meningoencephalitis). PSH can be seen in non-traumatic brain injury cases like meningitis. Due to a lack of awareness about this common but under-recognized entity, it is seldom diagnosed and treated. Early detection and treatment can be life-saving and improve patient outcomes. Earlier onset may be associated with poorer outcomes and mortality.