Head Injury Warning Signs

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The tricky part about head injuries is that the most dangerous ones do not always announce themselves right away. A person who takes a blow to the head and walks away talking can still be in serious trouble, not in the next five minutes, but in the next few hours or days. Blood pooling between the brain and the skull, brain swelling building slowly, a small bleed expanding into something critical: those processes often begin while the person feels relatively okay. Knowing the warning signs that separate a routine bump from a true traumatic brain injury is one of the most useful skills any coach, parent, or coworker can carry.

What follows covers the signs and symptoms of concussion, the specific danger signs that flag a life-threatening emergency, what to watch for in infants and toddlers, and the first aid steps for the hours after a hit to the head. The information follows CDC HEADS UP guidance on concussion recognition.

Common Signs of a Concussion

A concussion is a mild traumatic brain injury caused by a bump, blow, or jolt to the head that makes the brain move rapidly inside the skull. Most concussions do not involve a loss of consciousness; fewer than one in ten do. The absence of blacking out is not evidence the brain came through clean. Concussion symptoms can show up immediately or take hours to develop, and some people do not notice them until the next morning.

Concussion signs and symptoms fall into four categories. Physical symptoms include headache, nausea, vomiting, dizziness, blurry or double vision, sensitivity to light or noise, and balance problems. Cognitive symptoms include feeling foggy or slowed down, trouble concentrating or remembering, and confusion about what just happened. Emotional symptoms can include irritability, sadness, anxiety, or feeling more emotional than usual. Sleep symptoms include sleeping more or less than normal, trouble falling asleep, or unusual drowsiness during the day. Any combination of those symptoms after a hit to the head is a concussion until proven otherwise and deserves removal from the activity and a medical evaluation.

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One sign worth understanding on its own: repeated vomiting after a head injury (vomiting more than once) is a different signal than a single bout of nausea. A single vomit in the first minutes after a hard impact can be a concussion symptom. Repeated vomiting suggests pressure rising inside the skull and moves the picture from concussion territory into danger-sign territory.

Head Injury Danger Signs

Beyond concussion symptoms, there is a separate category of findings that flag a potentially life-threatening brain injury: a skull fracture, a bleed between the brain and the skull, or significant brain swelling. Those signs require an immediate emergency response, not watchful waiting.

The CDC identifies the following as danger signs in adults and older children after a head injury: one pupil larger than the other, extreme drowsiness or an inability to be woken up, a headache that is getting significantly worse rather than gradually better, slurred speech, repeated vomiting, seizures or convulsions, increasing confusion or unusual behavior, and loss of consciousness for any period. Any of those is a 911 call.

Two of those signs deserve particular attention because they are easy to underestimate. Slurred speech after a head injury is a neurological warning, since the areas of the brain that run speech are affected, which means the injury has reached past the surface. Unequal pupils, with one pupil visibly larger than the other, point to pressure building on one side of the brain and rank among the clearest indicators that something serious is happening. Neither finding should ever prompt “let’s wait and see.”

When to Call 911

Call 911 (do not drive the person to the hospital yourself) if the person loses consciousness at any point, has a seizure, vomits repeatedly, develops a worsening headache, has slurred speech or unequal pupils, or shows increasing confusion or agitation. Also call if the mechanism was severe: a high-speed crash on I-10, a fall from significant height, or a direct high-force impact to the skull.

As you wait on EMS, keep the person still and avoid moving the head or neck unless the airway requires it. If a spinal injury is also possible (it usually is in high-impact trauma), do not move the person unless they are in immediate danger and there is no time to wait. If the person is unconscious and breathing, the recovery position is appropriate only when a spinal injury has been ruled out or when they are at risk of choking. If they are not breathing, CPR takes priority over everything else.

One pattern people frequently misjudge: the person who seemed fine right after the hit but becomes progressively more confused or lethargic over the following hours. This pattern, called a “lucid interval,” is associated with epidural hematoma, a bleed in the space between the skull and the outer membrane of the brain. It is a medical emergency. The window between lucid interval and rapid deterioration can be short.

What to Watch for in Children

Infants and toddlers cannot describe what they are feeling, which makes head injury assessment harder in younger children. After a hit to the head in an infant or young child, watch for any of the following: a bump or bruise on the head, especially one that appears to be growing or feels soft and fluctuant in the center; prolonged or inconsolable crying that cannot be explained; unusual sleepiness or trouble waking; refusal to eat; vomiting more than once; seizures; loss of consciousness even briefly; or a marked change in behavior or alertness.

In older children who can communicate, the same concussion signs apply as in adults (headache, confusion, feeling foggy, balance problems, light sensitivity), plus age-specific signs like seeming dazed after the hit, not remembering what happened, or behaving differently than normal. Children recover from concussion at a different rate than adults and need a physician’s clearance before returning to sports, physical work, or a full academic load.

A specific caution for infants: any fall from a surface higher than the infant’s own length (a changing table, a couch, a high counter) is worth a call to the pediatrician or an urgent care visit, even if the infant looks fine. The infant skull is thinner and the brain less protected than an adult’s, and internal injuries can occur with no visible external sign.

What to Do After a Head Injury

For a head injury that does not involve the emergency danger signs above (a bump or a mild-to-moderate concussion), the priorities are rest and monitoring. Pull the person from the activity. Do not return to sports, physical work, or anything that demands real concentration until the symptoms have cleared. Both physical and cognitive rest matter: screens, reading, and intensive mental tasks can drag concussion symptoms out, and going back to physical activity before the brain has recovered raises the risk of a second concussion with much more serious consequences.

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Monitor the person for the first twenty-four hours. Keeping someone with a mild concussion awake all night is no longer recommended, but checking on them periodically to confirm they wake easily and respond normally is. If new symptoms appear during this period, or if the existing symptoms are getting noticeably worse rather than gradually better, get medical attention. Symptoms that take hours or days to fully emerge are normal with concussion. Worsening symptoms after the initial settle are not.

Acetaminophen is the right pain reliever during the first twenty-four hours after a head injury. NSAIDs like ibuprofen and aspirin act as blood thinners and should be avoided initially in case there is a small bleed that has not yet been ruled out. Follow up with a physician for any head injury involving loss of consciousness, confusion, repeated vomiting, or symptoms that are not starting to improve within a day or two.

FAQ

No, and this is one of the most common misconceptions about concussions. Fewer than ten percent of concussions involve loss of consciousness. Most people who get a concussion stay awake and alert but feel headache, confusion, fogginess, or balance problems. The absence of blacking out is not evidence the brain came through clean, and it is not a useful gauge of how serious the injury is.

A lucid interval is a stretch of apparent normalcy after a serious head injury, followed by rapid deterioration. It is most associated with epidural hematoma, a bleed between the skull and the outer membrane of the brain that builds pressure until the brain is compressed. The person may seem fine right after the hit and then become confused, lethargic, or unresponsive over the next few hours. That exact pattern is why post-injury monitoring is essential even when the person initially seems okay.

No, that recommendation is outdated. Current guidance allows sleep after a concussion because rest itself supports recovery. Check on the person periodically during the night to confirm they can be roused and are responding normally. If you cannot wake them, or if they seem confused or are not responding appropriately when woken, call 911. Normal sleep after a medically evaluated concussion is fine. Unresponsiveness is not.

Yes. Concussion symptoms can take hours or days to fully emerge. Someone who seems mildly affected the evening of a head injury may wake the next morning with a real headache, cognitive fogginess, or other symptoms. That delayed onset is part of why the CDC recommends a twenty-four-hour monitoring window and part of why returning to sports or strenuous activity right after a head injury is never appropriate, even when the person says they feel fine.

Acetaminophen (Tylenol) is the right choice for headache pain in the first twenty-four hours after a head injury. Avoid ibuprofen, aspirin, and other NSAIDs initially. They reduce clotting, and until a brain bleed has been ruled out, blood thinners carry additional risk. A headache that is severe, rapidly worsening, or not responding to acetaminophen is a signal to seek medical evaluation, not to reach for a stronger pain reliever.

CPR certification paired with First Aid training covers head injury assessment, the distinction between concussion and the danger signs, and what to do until EMS arrives. Our onsite training in Tallahassee is a strong fit for schools, athletic programs, and workplaces where head injuries are a real risk and the staff need hands-on practice with the response.

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