Assessing a head injury starts with checking for a few critical danger signs, then working through a series of simple observations that help you gauge severity. Most head injuries are mild, but the difference between “watch and wait” and “call 911” comes down to specific symptoms you can spot without any medical training. Whether you’re a parent, coach, or bystander, knowing what to look for in the first minutes and hours can make a real difference.
Danger Signs That Require Emergency Care
Some symptoms after a head impact signal a potential brain bleed or swelling that needs immediate treatment. Call 911 or go to the emergency department if the person:
- Has one pupil visibly larger than the other
- Vomits two or more times
- Has a seizure or convulsion
- Shows weakness, numbness, or loss of coordination
- Cannot be woken up or is increasingly difficult to rouse
- Has slurred speech that worsens over time
- Becomes confused or agitated beyond what the initial impact would explain
These signs apply to both adults and children. In infants and toddlers who can’t describe their symptoms, watch for inconsolable crying, refusal to eat, or a bulging soft spot on the skull.
How to Check Alertness and Awareness
The most widely used tool for gauging consciousness after a head injury is the Glasgow Coma Scale, which scores three things: eye opening, verbal responses, and motor (movement) responses. You don’t need to memorize the full scale, but understanding the basics helps you describe the situation clearly if you call for help.
Eye opening: Does the person open their eyes on their own (best response), only when you speak to them, only when you apply a painful stimulus like a firm pinch, or not at all (worst response)?
Verbal response: Can the person tell you their name, where they are, and what happened? If they’re confused but still forming sentences, that’s better than producing only random words or incomprehensible sounds. No verbal response at all is the most concerning.
Motor response: Ask the person to squeeze your fingers or lift their arms. Following commands is the best sign. If they only pull away from pain, or if their limbs stiffen or extend abnormally, the injury is more serious.
Scores on this scale range from 3 (completely unresponsive) to 15 (fully alert and oriented). A score of 13 to 15 is classified as a mild traumatic brain injury, 9 to 13 is moderate, and 3 to 8 is severe. Even without calculating a number, the key question is simple: is this person getting better, staying the same, or getting worse? Any decline in alertness after a head injury is a reason to seek emergency care immediately.
Assessing a Child’s Head Injury
Children, especially those under two, need a slightly different approach because they can’t always tell you what they feel. Pediatric emergency guidelines use two age groups with different warning signs.
For children under 2 years, the main things to check are: Is the child acting normally (per the caregiver who knows them best)? Was there any loss of consciousness? Is there a bump or swelling on the side or back of the head rather than the forehead? Does the scalp feel abnormal in a way that might suggest a skull fracture? A bump on the forehead in a toddler is generally less concerning than swelling on the side or back of the head, where the skull is thinner.
For children ages 2 to 15, the checklist shifts slightly. Key concerns include loss of consciousness, vomiting, a severe headache, signs of a skull fracture (like bruising behind the ears or around the eyes), and whether the injury was caused by a high-force mechanism such as a car crash, a fall from a significant height, or being struck by a fast-moving object. If none of these factors are present and the child’s mental status is normal, the risk of a serious brain injury is very low.
Assessing a Sports Concussion on the Sideline
If someone takes a hit during a game or practice, the current standard sideline assessment (known as SCAT6) follows a specific sequence that coaches and athletic trainers can adapt.
Start with observable signs: Did the person lose consciousness, even briefly? Do they seem dazed, slow to get up, or unsteady? Are they clutching their head or showing a blank expression? Any of these means they should be removed from play immediately.
Next, check orientation and memory. Ask simple questions: What venue are we at? Which half is it? Who scored last? What team did we play last week? These are called Maddocks questions, and someone with a concussion will often struggle with details they’d normally know without thinking.
Then test concentration and balance. For concentration, ask the person to recite the months of the year in reverse order, starting from December, or repeat a string of numbers backward. For balance, have them stand with feet together, eyes closed, for 20 seconds. Then try a tandem stance (heel to toe) and a single-leg stance. A person with a concussion often sways noticeably or needs to open their eyes to stay upright. You can also ask them to walk heel-to-toe in a straight line while timing them.
Finally, test delayed memory. Give the person a short list of five words at the start of the assessment, then ask them to recall the words 10 to 15 minutes later. Difficulty with this recall is one of the more sensitive indicators of concussion.
No single test confirms a concussion on its own. The combination of symptoms, balance problems, and cognitive difficulty paints the full picture. When in doubt, sit them out.
When a CT Scan Is Needed
Not every head injury requires a brain scan. Emergency physicians use established criteria to decide whether imaging is necessary, and understanding these factors helps you know what to expect if you go to the ER.
High-risk factors that strongly point toward needing a scan include: the person still isn’t fully alert two hours after the injury, there are signs of a skull fracture (a visible dent, fluid leaking from the nose or ears, bruising behind the ears), the person has vomited two or more times, or they’re 65 or older. Age matters because older adults are more prone to bleeding inside the skull, even from relatively minor impacts.
Medium-risk factors include not being able to remember the 30 minutes before the injury, or the injury involving a dangerous mechanism like being hit by a vehicle, falling from more than three feet (or five stairs), or being ejected from a moving vehicle.
If none of these factors apply and the person is fully alert and oriented, imaging is typically unnecessary. This is important because CT scans involve radiation exposure, and avoiding unnecessary scans, particularly in children, is a meaningful benefit.
Monitoring a Mild Head Injury at Home
If you’ve been cleared to go home, or if the injury seems clearly minor, the first 24 to 48 hours are the most important observation window. During this period, someone should check on the injured person regularly, including waking them once or twice during the night to confirm they respond normally and can answer simple questions.
What to watch for during home monitoring:
- A headache that steadily worsens rather than gradually improving
- New vomiting that starts hours after the injury
- Increasing drowsiness or difficulty waking
- New confusion or personality changes
- Weakness on one side of the body
- Unequal pupil size
Encourage rest and limit screen time in the first 24 to 48 hours, since bright screens and mentally demanding tasks can worsen symptoms like headache and difficulty concentrating. Light activity like short walks is fine once the person feels up to it, but intense physical exertion and contact sports should be avoided until symptoms have fully resolved.
Why Delayed Symptoms Matter
One of the trickiest aspects of head injuries is that some people feel fine initially, then deteriorate hours later. This pattern, sometimes called a lucid interval, happens when bleeding inside the skull is slow enough that symptoms don’t appear right away. The brain can compensate for a small amount of pressure, but once the blood collection reaches a tipping point, the person may suddenly become confused, drowsy, or unresponsive.
This is why the 24 to 48 hour monitoring window exists. Most dangerous complications from a head injury will declare themselves within that period. Certain types of brain bleeding, particularly those involving the thin arteries between the skull and brain covering, can progress from “feeling okay” to a life-threatening emergency within hours. Any new or worsening symptom after a head injury, even if the person initially seemed fine, warrants emergency evaluation. The earlier a brain bleed is identified, the better the outcome.