Differential Disruption of Blood–Brain Barrier in Severe Traumatic Brain Injury

Background Traumatic brain injury (TBI) is a significant cause of death and disability in young adults, but not much is known about the incidence and characteristics of blood–brain barrier (BBB) dysfunction in this group. In this proof of concept study, we sought to quantify the incidence of BBB dysfunction (defined as a cerebrospinal fluid (CSF)–plasma albumin quotient of ≥0.007) and examine the relationship between plasma and CSF levels of proteins and electrolytes, in patients with severe TBI. Methods We recruited 30 patients, all of whom were receiving hypertonic 20 % saline infusion for intracranial hypertension and had external ventricular drains in situ. Simultaneous CSF and blood samples were obtained. Biochemical testing was performed for sodium, osmolality, potassium, glucose, albumin, immunoglobulin-G, and total protein. Results Eleven patients (37 %) showed evidence of impairment of passive BBB function, with a CSF–plasma albumin quotient of ≥0.007. There were strong positive correlations seen among CSF–plasma albumin quotient and CSF–plasma immunoglobulin-G quotient and CSF–plasma total protein quotient ( r = 0.967, P