Call 911 or go to the nearest emergency department for any of the danger signs below
When in doubt, it is always safer to be evaluated. These signs can mean something more than a concussion, such as bleeding or swelling inside the skull.
A concussion is a mild traumatic brain injury that temporarily changes how brain cells work, even when the brain looks completely normal on a scan. This page will help you recognize the symptoms, know which signs mean you need care right away, and understand how recovery works.
A concussion is a head injury that impacts brain function, even when that injury cannot be seen on a CT scan or MRI.
A concussion can follow a bump, blow, or jolt to the head, or can result from a hit elsewhere on the body that shakes the head, causes the brain to move rapidly inside the skull. The brain is soft and suspended in fluid, so a sudden change in speed or direction can cause the brain to impact the skull, or to stretch or compress as it moves.
That stretching briefly disrupts the normal chemical and electrical balance inside brain cells, sometimes called a neurometabolic cascade. This is a functional injury: the brain's wiring is temporarily working differently, not structurally torn or bleeding. That is why imaging so often looks normal after a concussion, even though the symptoms are completely real.
A neurosurgical operation is generally not required for concussions; sometimes, neurosurgery gets involved when brain imaging is suggestive of possible visible injury, otherwise concussions are typically managed by primary care doctors, neurologists, neuropsychologists, and occasionally dedicated concussion specialists from any of these areas.
Symptoms differ from person to person, can change during recovery, and are usually most severe in the first day or two. Select a category, then a symptom, to learn more.
When in doubt, it is always safer to be evaluated. These signs can mean something more than a concussion, such as bleeding or swelling inside the skull.
Not every symptom after a head injury is dangerous, and warning signs can appear hours or days after the injury, not only right away. Select a sign below to learn why it matters.
Recovery is guided by symptoms, not by the calendar. Both tracks below move forward in graduated steps, resting on the same underlying rule.
The rule for every step, on both tracks: each stage takes a minimum of 24 hours, and you only move to the next stage once you can complete the current one without your symptoms getting worse. If symptoms return, drop back to the last stage where you felt fine.
Most people recover fully and quickly. A smaller number need more support, and everyone benefits from understanding one specific, preventable danger.
About 1 in 5 people still have concussion symptoms, such as headache, dizziness, and trouble concentrating, beyond the usual 2-to-4-week window. When symptoms persist longer than about a month, this is often called post-concussion syndrome.
Risk is higher for people with a history of prior concussions, migraine, anxiety or depression, and in adolescents. Most people with post-concussion syndrome still improve over time, often with targeted therapies (vestibular therapy for balance, vision therapy for eye coordination, and headache management) rather than strict rest, paced by symptoms rather than a fixed timeline.
Second impact syndrome is a rare but often catastrophic complication in which a person sustains a second head injury, sometimes a relatively minor one, before fully recovering from a first concussion. In susceptible individuals, this can trigger rapid, severe brain swelling.
Reported mortality is roughly 50%, and nearly all survivors are left with permanent disability. It is the single clearest reason never to return to sports, or any activity with a real risk of another head impact, while still symptomatic from a prior concussion.
Concussion care at Brown draws on our Division of Neurotrauma, working alongside rehabilitation specialists to guide recovery and recognize the rare cases that need surgical attention.
