Concussion

A concussion, classified as a mild traumatic brain injury (mTBI), is a head injury that disrupts brain function on a temporary basis. It is the most frequent form of traumatic brain injury, with an estimated annual global incidence exceeding 3.5 cases per 1,000 people, and it occurs most often in males and young adults.

Causes range from motor vehicle collisions, falls, and sports injuries to bicycle accidents. Risk factors include physical violence, alcohol consumption, and having had a prior concussion. The injury results from either a direct blow to the head or a force applied elsewhere that transmits to the head, leading to neuron dysfunction due to increased glucose demand without adequate blood supply.

Symptoms vary by person and can be physical, cognitive, or emotional. Common physical signs include headache, dizziness, nausea, vomiting, balance problems, blurred or double vision, light sensitivity, and tinnitus. Cognitive symptoms involve confusion, disorientation, difficulty concentrating, brief memory loss, and brief loss of consciousness. Emotional changes such as mood swings may also occur. Symptoms typically appear within minutes to hours of the injury, usually within 72 hours, but can be delayed by one to two days. In adults, symptoms often resolve within two weeks; in children, they may last up to four weeks. For some—up to one-third of cases—symptoms persist longer, defined as more than 14 days in adults and over four weeks in children and adolescents. The severity of initial symptoms is the strongest predictor of recovery time in adults.

A concussion should be suspected after any head impact accompanied by these symptoms. Diagnosis requires a thorough evaluation by a qualified medical provider to rule out life-threatening head injuries, cervical spine damage, and other neurological conditions. A Glasgow Coma Scale score of 13 to 15, loss of consciousness under 30 minutes, and memory loss under 24 hours help distinguish concussion from moderate or severe brain injuries. Imaging like CT or MRI may be used to exclude severe injuries, but routine scans are not needed for diagnosis and are typically normal after a concussion.

Prevention strategies include wearing helmets and mouthguards during sports, using seatbelts in vehicles, enforcing rules against body checking in organized sports, and performing neuromuscular warm-up exercises. Treatment involves relative rest for no more than one to two days, followed by gradual aerobic exercise and a stepwise return to activities, school, or work. Prolonged rest can slow recovery and increase depression and anxiety. Headaches may be managed with acetaminophen or NSAIDs. Prescribed aerobic exercise can aid recovery, while physiotherapy may help with persisting balance issues, headache, or whiplash. Cognitive behavioral therapy can address mood changes and sleep problems. Evidence does not support hyperbaric oxygen therapy or chiropractic care for concussion.

Outcomes are generally favorable, with disability typically lasting days to weeks. However, sustaining another concussion before prior symptoms resolve leads to worse outcomes. Repeated concussions may raise the later risk of chronic traumatic encephalopathy, Parkinson’s disease, and depression. Fewer than 10% of sports-related concussions in children involve loss of consciousness. Concussive convulsions, occurring in about one in seventy cases, are not linked to epilepsy or structural damage and carry the same good prognosis as concussions without convulsions.