A narrative review of risk factors and predictors for poor outcome and prolonged recovery after a mild traumatic brain injury.

Mild traumatic brain injuries (mTBI) are often caused by a blow to the head or a sudden jolt resulting in a wide range of physical, cognitive, and emotional temporary symptoms. Mild TBI diagnosis can be challenging and most commonly followed by post-concussion syndrome (PCS). When the symptoms are present for more than 3 months, prolonged post-concussive syndrome (PPCS) can be suspected. This review aims to identify and summarize the current status of the knowledge regarding the risk factors and predictors of the recovery from PCS and PPCS. A comprehensive search of the main scientific databases (PubMed, Web of Science, Embase, and Cochrane Library) was performed using keywords, such as: 'prolonged post-concussion syndrome', combined with 'risk factors', 'predictors', and 'outcomes'. Multiple studies reported more than one risk factor for PPCS development following mTBIs that were generally the results of sports-related concussions and car accidents. The most prevalent risk factor associated with PPCS was the female sex. Social factors/personality traits, anxiety, mental health disorders, or other health conditions from their past medical history, the occurrence of headache/migraines during TBI recovery, somatization, physical activity, and litigation were also reported to contribute to PPCS risk. An exhaustive approach is required to mitigate the risk of PPCS and to ensure optimal recovery after concussive events. However, larger prospective cohort studies evaluating patients that were examined and treated with standardized protocols could be needed to further validate these associations and mandate the highest risk factors for delayed recovery.