Biomarkers and acute brain injuries: interest and limits

For patients presenting with acute brain injury (such as traumatic brain injury, subarachnoid haemorrhage and stroke), the diagnosis and identification of intracerebral lesions and evaluation of the severity, prognosis and treatment efficacy can be challenging. The complexity and heterogeneity of lesions after brain injury are most probably responsible for this difficulty. Patients with apparently comparable brain lesions on imaging may have different neurological outcomes or responses to therapy. In recent years, plasmatic and cerebrospinal fluid biomarkers have emerged as possible tools to distinguish between the different pathophysiological processes. This review aims to summarise the plasmatic and cerebrospinal fluid biomarkers evaluated in subarachnoid haemorrhage, traumatic brain injury and stroke, and to clarify their related interests and limits for diagnosis and prognosis. For subarachnoid haemorrhage, particular interest has been focused on the biomarkers used to predict vasospasm and cerebral ischaemia. The efficacy of biomarkers in predicting the severity and outcome of traumatic brain injury has been stressed. The very early diagnostic performance of biomarkers and their ability to discriminate ischaemic from haemorrhagic stroke were studied.