Traumatic brain injury (TBI) happens when a force damages the brain – a blow to the head, a fall, a crash or a violent jolt that makes the brain move inside the skull. The symptoms depend on how severe the injury is and which part of the brain is affected. Some appear immediately, others only hours or days later. Knowing the typical signs and the danger signals helps to get the right care in time.
Mild TBI: The Symptoms of a Concussion
Most traumatic brain injuries are mild; doctors usually call them concussions. A person does not have to be knocked out to have a concussion – most people with a concussion never lose consciousness. The CDC groups concussion symptoms into four areas.
Physical symptoms
- Headache or a feeling of pressure in the head
- Nausea or vomiting
- Dizziness and balance problems
- Blurred or double vision
- Sensitivity to light or noise
- Ringing in the ears
- Feeling tired, having no energy
Thinking and memory
- Feeling foggy or slowed down
- Trouble concentrating
- Problems remembering new information
- Confusion about recent events; repeating the same questions
Emotions and mood
- Irritability and short temper
- Sadness
- Nervousness or anxiety
- Being more emotional than usual
Sleep
- Sleeping more than usual
- Sleeping less than usual or trouble falling asleep
Some of these signs are obvious right after the injury. Others – such as problems with concentration or sleep – are noticed only when the person tries to return to work, school or daily routines.
Danger Signs: When to Call 911
After any head injury, the following signs point to a possible bleed or dangerous swelling in the brain. They require emergency care immediately:
- One pupil larger than the other
- Drowsiness or inability to wake up
- A headache that gets worse and does not go away
- Slurred speech, weakness, numbness or decreased coordination
- Repeated vomiting or nausea
- Convulsions or seizures
- Unusual behavior, increasing confusion, restlessness or agitation
- Loss of consciousness, even briefly
Bleeding inside the skull can build up pressure over hours. A person who seemed fine at first can deteriorate quickly – this is typical of an epidural hematoma. More about the different forms of bleeding is in Types of Traumatic Brain Injury.
Signs in Babies and Young Children
Infants and toddlers cannot say that they have a headache or see double. Parents and caregivers have to watch for changes in behavior:
- Crying that cannot be calmed
- Refusing to nurse or eat
- Vomiting
- Unusual sleepiness or listlessness, or more irritability than usual
- Loss of interest in favorite toys
- A bulging soft spot (fontanelle) on the head
- Loss of skills already learned, such as walking or toilet training
Any of these signs after a fall or a blow to the head is a reason to see a doctor right away; a bulging soft spot, seizures or unresponsiveness are reasons to call 911. In babies, shaking can cause severe brain injury without any visible wound. Further information is in the article on brain injury in children.
Older Adults: Small Falls, Serious Risk
Falls are the most common cause of TBI hospitalizations, and the risk is highest among adults aged 75 and older. With age, the brain shrinks slightly and the veins on its surface stretch, so they tear more easily. Many older adults also take blood thinners such as warfarin, apixaban or rivaroxaban, or antiplatelet drugs like clopidogrel.
For this group, even a seemingly minor fall can cause bleeding in the head. Guidelines therefore recommend a medical exam – usually with a CT scan – for older adults on blood thinners after any blow to the head. A chronic subdural hematoma can develop over weeks; new confusion, headaches, unsteady walking or changes in personality after a fall should be checked.
Moderate and Severe TBI
In moderate and severe TBI, the person is often unconscious for a longer time – minutes, hours or more. Severe TBI can lead to a coma. Some patients pass through a vegetative state (unresponsive wakefulness syndrome) or a minimally conscious state before they regain consciousness. Recovery in these cases takes months and requires specialized care.
Signs of a moderate or severe brain injury can include:
- A long period of unconsciousness or confusion
- Persistent or worsening headache, repeated vomiting
- Seizures
- Dilated or unequal pupils
- Clear fluid from the nose or ears
- Weakness or paralysis on one side, problems with coordination
- Trouble speaking or understanding language
Very high pressure inside the skull can show as decreasing consciousness, pupils that no longer react to light, a slow heart rate, irregular breathing and abnormal stiff postures of the arms and legs. These are signs of a life-threatening situation.
Long-Term Effects
After moderate and severe TBI – and in some cases after a concussion – problems can last a long time:
- Thinking: memory, attention, planning, slowed processing
- Communication: finding words, following conversations, reading and writing
- Movement and senses: weakness, spasticity, balance, vision and hearing
- Behavior and emotions: impulsivity, irritability, depression and anxiety
- Other: chronic headaches, fatigue, epilepsy after the injury
Rehabilitation with physical, occupational and speech therapy as well as neuropsychology helps to train lost abilities and develop strategies for daily life.
Recovery From a Concussion
Most concussion symptoms improve within a few days to a few weeks. A short period of relative rest during the first one to two days is recommended, followed by a gradual return to light activity – complete rest in a dark room for many days is no longer advised. Sports with a risk of new head injuries must wait until the doctor gives clearance. Students often need a “return to learn” plan with reduced workload at school. A second concussion before the first has healed can prolong recovery. Symptoms that last longer than about four weeks should be evaluated by a specialist.
Frequently Asked Questions
Does a concussion always involve losing consciousness?
No. Most people with a concussion never pass out. Headache, dizziness, confusion or memory gaps after a blow to the head can be signs of a concussion even without unconsciousness.
Can symptoms of a brain injury appear later?
Yes. Some symptoms appear only hours or days after the injury, and a chronic subdural hematoma can develop over weeks. New or worsening symptoms after a head injury need a medical check.
When does a child need emergency care after a head injury?
If the child cannot be calmed, vomits repeatedly, will not eat, is unusually sleepy, has a seizure or a bulging soft spot, call 911 or go to the emergency department immediately.
How long do concussion symptoms last?
Most improve within days to weeks. In some people, problems such as headaches, fatigue or difficulty concentrating last for months and need specialized follow-up care.
