When you go to the emergency room after a head injury, the medical team follows a structured process: assess how severe the injury is, determine whether you need a brain scan, monitor you for dangerous complications, and send you home with a recovery plan. Most concussions don’t require surgery or admission to the hospital, so the ER’s primary job is ruling out something worse, managing your immediate symptoms, and making sure you know what to watch for over the next few days.
The Neurological Exam
The first thing the ER team does is evaluate your brain function. This starts with the Glasgow Coma Scale, a scoring system that rates your ability to open your eyes, speak, and move on command. A score of 13 to 15 indicates a mild traumatic brain injury, which is the clinical term for a concussion. Most people who come in alert and talking score in this range.
Beyond the GCS score, the exam covers several areas. A provider will check your mental status by asking you to recall three objects after a few minutes or subtract numbers in sequence. They’ll test your cranial nerves by shining a light in your eyes, checking your facial symmetry, and assessing your ability to track objects. They’ll also evaluate your strength, sensation, and reflexes in your arms and legs. The goal is to detect any focal neurological deficits, meaning problems isolated to one side or one part of the body, which could signal bleeding or swelling in the brain.
Deciding Whether You Need a CT Scan
Not every concussion patient gets a CT scan. Emergency physicians use validated decision tools to figure out who actually needs imaging and who can safely skip it. The Canadian CT Head Rule is one of the most widely used. It applies to patients who lost consciousness, have amnesia, or were disoriented after the injury. If you meet those criteria, you’ll almost certainly get a scan.
Certain red flags make imaging mandatory regardless of the decision tool. These include repeated vomiting, seizures after the injury, signs of a skull fracture (like fluid leaking from the nose or ears), worsening drowsiness, and any new neurological problems such as weakness on one side of the body. If you take blood thinners, that alone is enough to warrant a scan, because even a minor bleed can expand rapidly when clotting is impaired.
For children, the ER uses a separate set of criteria called the PECARN algorithm, which is tailored by age. For kids under two, providers look at things like abnormal behavior (as reported by the caregiver), scalp swelling that isn’t on the forehead, and evidence of skull fracture. For children two to fifteen, the key factors include loss of consciousness, vomiting, severe headache, and signs of a fracture at the base of the skull. If none of these are present, the child is classified as low risk and can usually avoid a CT scan, which matters because reducing unnecessary radiation exposure in children is a priority.
Blood Tests for Concussion
A newer option available in some ERs is a blood test that measures two proteins released by brain cells after injury. The test, cleared by the FDA in 2021, can help determine whether there’s a brain lesion that would show up on a CT scan. These proteins are normally present only in tiny amounts, so elevated levels after a head injury suggest the brain has been damaged enough to warrant imaging. The blood test doesn’t replace a CT scan but can help identify patients who don’t need one, potentially sparing them the radiation and the wait.
Observation in the ER
If your CT scan comes back normal, you’re not necessarily sent home right away. The standard protocol at many hospitals is a six-hour observation period after arrival. During this time, the medical team periodically re-checks your neurological status to make sure nothing is getting worse. Bleeding inside the skull can develop slowly, so a normal scan taken shortly after injury doesn’t guarantee you’re completely in the clear.
During observation, the staff monitors for changes in your alertness, speech, coordination, and pupil size. If you remain stable and your repeat exam looks good, you’ll be cleared for discharge. Some hospitals have adopted early discharge protocols for patients whose scans are normal and whose symptoms are mild and stable, but the six-hour window remains a common benchmark.
What Happens if the Scan Shows Something
Most concussion patients have normal imaging, but when a CT scan reveals bleeding, a skull fracture, or brain swelling, the ER response escalates. You may be admitted to the hospital for closer monitoring, referred to a neurosurgeon for evaluation, or in rare severe cases, taken to surgery to relieve pressure on the brain. This is the main reason the ER visit matters: catching the small percentage of concussions that are actually hiding a more dangerous injury underneath.
Discharge Instructions and Early Recovery
For the majority of patients who are evaluated, observed, and cleared, the ER visit ends with a detailed set of discharge instructions. These have changed significantly in recent years. The old advice was strict bed rest in a dark room for days. Current guidelines recommend a much more active approach.
The first 24 to 48 hours call for relative rest. That means scaling back screen time, physical exertion, and mentally demanding tasks, but not lying in bed doing nothing. The CDC recommends taking no more than one to two days off from work or school. Relaxing activities like reading or taking a short walk are encouraged even during this initial window.
After that brief rest period, you should start easing back into your regular routine. Light aerobic activity like walking or stationary cycling is the next step. You can gradually increase the intensity every 24 hours as long as your symptoms stay mild and resolve within about an hour. If symptoms flare up, you drop back to the previous level and try again the next day.
The ER will typically provide written instructions covering what symptoms to watch for at home (worsening headache, repeated vomiting, confusion, seizures, or unusual drowsiness), a timeline for follow-up with your primary care provider, and restrictions on specific activities. You should not return to contact sports on the same day as the injury, and premature return before full clinical recovery raises the risk of second impact syndrome, prolonged symptoms, and worse outcomes overall.
If you’re a student or employed, the discharge paperwork often includes an excuse note with specific accommodations: frequent rest breaks, extra time on assignments and tests, and restrictions on physical activities that could lead to another hit to the head. These notes can be critical for managing the first week or two of recovery without falling behind.
What the ER Does Not Do
The ER is designed to handle the acute phase. It rules out emergencies, stabilizes you, and points you toward recovery. It does not manage long-term concussion symptoms. If you’re still dealing with headaches, brain fog, dizziness, or mood changes weeks after your injury, that follow-up care falls to your primary care provider or a concussion specialist. The ER discharge instructions should include a recommendation for when to schedule that appointment, typically within a few days of the injury.