Type and occurrence of serious complications in patients after mild traumatic brain injury.

Traumatic brain injury (TBI) remains a major public health and socio-economic problem, and 70-90% of all TBIs are classified as mild. Mild TBIs and concussions are mostly considered to be non-serious conditions with symptoms subsiding within a few days or weeks. However in 10-15% of patients, the symptoms persist one year after concussion and mostly include headache, fatigue, irritability, and cognitive problems (e.g. memory, concentration). These persisting symptoms negatively influence patient daily activities as postconcussion syndrome (PCS). Second-impact syndrome (SIS) is a very rare but usually fatal condition and occurs when repeated brain injuries lead to a catastrophic diffuse brain swelling. There is no scientific evidence on the incidence and risk of SIS. Chronic traumatic encephalopathy (CTE) is a progressive degenerative disease of the brain found in patients with a history of repetitive brain trauma. CTE presents with behavioural, cognitive, and motor symptoms. The literature to date lacks prospective epidemiological studies of the incidence of CTE. In recent medical literature, there is a description of 110 athletes with postmortem diagnosis of CTE (Tab. 1, Ref. 37).