Serum cleaved tau protein levels and clinical outcome in adult patients with closed head injury.

Intracranial injuries (ICI) are associated with high mortality and morbidity. Unfortunately, tools for diagnosis and risk stratification of ICIs are limited in the emergency department setting. We determine the relationship between the presence or absence of a detectable cleaved serum tau protein (tau(c)), ICI, and outcome at hospital discharge in adults with closed head injuries (CHI). This was a prospective pilot study of adult patients with CHI presenting to the ED of an urban Level I trauma center. Patients presenting within 10 hours of a CHI who underwent a head computed tomographic (CT) scan were eligible. A blood sample was collected at presentation and the tau(c) level was measured. Initial Glasgow Coma Scale scores and demographic information were recorded. A chart review was performed to determine outcome and final readings on the initial head CT scan. Patients were dichotomized to 1 of 2 groups, those with an ICI (n=17) and those with an isolated skull fracture or no CT abnormality (NICI) (n=11). The 2 groups were similar in regard to demographic composition, mechanism of injury, and coexisting injuries. A tau(c) level of more than 0 was associated with an increased chance of an ICI on the initial head CT scan (odds ratio 11.25; 95% confidence interval [CI] 1.17 to 108.4) and a greater chance of poor outcome, defined as death while in hospital or transfer to a nursing home at hospital discharge (odds ratio 8.17; 95% CI 1.42 to 47). A tau(c) level of more than 0 is associated with a greater chance of intracranial injury and poor outcome in patients with CHI.