Paroxysmal Sympathetic Hyperactivity

Paroxysmal sympathetic hyperactivity (PSH) is a clinical syndrome associated with many types of acquired brain injuries characterized by episodic uncontrolled physiologic surges of sympathetic activity. It features varying combinations and degrees of hyperthermia, diaphoresis, tachycardia, hypertension, tachypnea, and dystonic posturing. This constellation of symptomatology has been acknowledged in acquired brain injury for decades, but due to confusing nomenclature and inconsistent clinical definitions, its recognition and treatment as a syndrome have only recently begun to become more standardized. At this time PSH remains a diagnosis of exclusion, but one with which clinicians in the acute care setting should be familiar since its development is associated with longer hospital stays, higher rates of complications, and increased costs of care. Furthermore, delayed recognition and treatment can result in higher morbidity and worse outcomes.