Paroxysmal sympathetic hyperactivity after acquired brain injury: A review of diagnostic criteria

Primary objective: To evaluate the development and usage of diagnostic criteria for paroxysmal sympathetic hyperactivity (PSH) following acquired brain injury (ABI), then comparatively analyse published criteria. Research design: Systematic literature review. Methods and procedures: Literature published in English language prior to 30 November 2008 was reviewed for dysautonomic syndromes following ABI, characterized by simultaneous paroxysmal autonomic hyperactivity and motor over-activity. Main outcome and results: Sixty papers presenting 349 cases of PSH were identified, with a further 21 papers providing additional information regarding the condition. Only 27 of these 81 papers (33%) utilized diagnostic criteria. There were nine novel or substantially modified diagnostic criteria sets, which were analysed further. Criteria showed strong agreement on core clinical features of PSH - heart rate (HR), blood pressure, respiratory rate, temperature, sweating, and motor hyperactivity. Most criteria sets utilized a polythetic diagnostic system and all but one indicated severity thresholds, e.g. HR >120 beats per minute. Two papers specified a minimum episode frequency and four papers required a minimum syndrome duration. Conclusions: Of necessity, diagnostic criteria have been developed ad hoc. The differences between criteria complicate both clinical diagnosis and the process of comparing research cohorts. These findings demarcate the need for a single set of PSH diagnostic criteria and provide the substrate for scientific consensus.