Traumatic Brain Injury (TBI)

How TBI happens

The brain floats in fluid inside the skull. A blow or rapid acceleration and deceleration can:

• bruise the brain (contusion)
• stretch and tear nerve fibers (diffuse axonal injury)
• tear blood vessels, causing bleeding inside or around the brain
• cause swelling (cerebral edema), raising pressure inside the skull

Secondary injury from low oxygen, low blood pressure and swelling can worsen damage in the hours and days after the event.

Causes

• falls, the leading cause, especially in young children and older adults
• motor vehicle crashes
• being struck by or against an object, including sports injuries
• assaults
• blast injuries in military service

Severity of TBI

Symptoms

Mild TBI (concussion)

• headache, dizziness, nausea
• confusion, feeling foggy or slowed down
• memory problems around the event
• sensitivity to light and noise
• fatigue, sleep changes
• irritability, anxiety, emotional changes

See concussion for details.

Moderate to severe TBI

• prolonged unconsciousness or coma
• persistent or worsening headache
• repeated vomiting
• seizures
• weakness, numbness, speech problems
• unequal pupils
• clear fluid from the nose or ears

Bleeding after a head injury

Diagnosis

• Glasgow Coma Scale and neurological exam
• CT scan of the head: recommended using decision rules (such as the Canadian CT Head Rule or PECARN for children) for people with risk factors like age over 65, blood thinners, vomiting, dangerous mechanism or reduced alertness
• MRI: for persistent symptoms or when CT does not explain them
• blood biomarker tests (GFAP and UCH-L1) can help decide whether a CT is needed in mild TBI
• cervical spine assessment, as neck injuries often coexist

Treatment

Mild TBI

• brief relative rest for 24 to 48 hours, then gradual return to activity, as tolerated
• limit screens and demanding mental tasks early on, then reintroduce
• acetaminophen (paracetamol) for headache, following the label dose. Avoid NSAIDs in the first day or two unless advised, and avoid alcohol
• graded return to school, work and sport. Never return to contact sport on the same day as a concussion

Moderate and severe TBI

• emergency stabilization of airway, breathing and blood pressure
• intensive care with control of brain pressure
• surgery to remove blood clots or relieve pressure (craniotomy or decompressive craniectomy)
• seizure prevention in the early phase
• rehabilitation: physical, occupational, speech and cognitive therapy

Long-term effects

• post-concussion syndrome: headache, dizziness, fatigue and concentration problems lasting months
• memory, attention and executive function problems
• mood changes, depression, anxiety, PTSD
• post-traumatic seizures
• hormone problems from pituitary injury
• higher risk of dementia
• chronic traumatic encephalopathy: a degenerative condition linked to repeated head impacts in contact sports

Prevention

• wear seat belts and use child car seats
• wear helmets for cycling, skating, skiing, motorcycling and contact sports
• prevent falls at home: remove trip hazards, use grab bars and good lighting, review medicines in older adults
• install window guards and stair gates for young children
• follow concussion protocols in sports

Frequently asked questions

What are the signs of a traumatic brain injury?

Signs include headache, confusion, dizziness, nausea, memory loss, sensitivity to light and noise, and changes in mood or sleep. Serious signs are loss of consciousness, worsening headache, repeated vomiting, seizures, weakness, slurred speech and unequal pupils, which need emergency care.

Is a concussion a traumatic brain injury?

Yes. A concussion is a mild traumatic brain injury. It is called mild because it is not usually life-threatening, but it can still cause significant symptoms that take days to weeks, and sometimes longer, to resolve.

When should I go to the ER after hitting my head?

Go to the ER if you lost consciousness, have a worsening headache, vomit repeatedly, feel increasingly drowsy or confused, have a seizure, weakness, slurred speech, unequal pupils or clear fluid from the nose or ears, or if you take blood thinners or are over 65.

How long does it take to recover from a TBI?

Most people with a mild TBI recover within 2 to 4 weeks, though some have symptoms for months. Recovery from moderate or severe TBI can take months to years, and some people have lasting effects that rehabilitation helps them manage.

Can a brain injury cause problems years later?

Yes. Some people have lasting memory, mood or concentration problems, epilepsy, or hormone issues. Moderate to severe TBI increases the risk of dementia, and repeated head impacts are linked to chronic traumatic encephalopathy.