A head injury causing temporary or lasting disruption to brain function, from mild concussion to severe TBI.

Overview

What is a traumatic brain injury (TBI)?

• A traumatic brain injury (TBI) is an injury that affects how the brain works. It happens when a sudden bump, blow, jolt, or penetrating injury to the head disrupts normal brain function.
• TBI is not one single condition — it covers a wide range from mild (concussion) to severe, life-threatening brain damage.
• There were over 69,000 TBI-related deaths in the United States in 2021 — approximately 190 deaths every day.

What is a concussion?

• A concussion is the most common type of TBI. It is also called a mild TBI (mTBI). The word 'mild' refers to the fact that it is usually not life-threatening — but its effects can still be very serious.
• A concussion happens when a bump, blow, or jolt to the head — or even a hit to the body — causes the brain to move rapidly back and forth inside the skull. This movement creates chemical changes in the brain and can stretch or damage brain cells.

Types of TBI

• Mild TBI / Concussion — temporary disruption of brain function; most common type
• Moderate TBI — longer loss of consciousness (30 minutes to 24 hours); significant symptoms; may require hospitalisation
• Severe TBI — extended loss of consciousness or coma; can cause permanent disability or death

Causes

• Falls — the leading cause of TBI across all ages, especially in older adults and young children
• Road traffic accidents — collisions involving cars, motorcycles, bicycles
• Sports and recreational injuries — contact sports (football, rugby, hockey, boxing, martial arts)
• Being struck by or against an object
• Physical violence or assault
• Blast injuries — a leading cause among military personnel
• Penetrating injuries — such as gunshot wounds to the head
• Young children (especially under 4 years) — falls and non-accidental injury
• Teenagers and young adults — sports injuries and road accidents
• Adults over 75 years — falls are the leading cause in this age group
• Military personnel — blast and combat injuries
• People with a previous concussion — repeat injuries carry greater risk
• Men — more commonly affected than women overall

Symptoms

Symptoms of concussion/mild TBI

Symptoms may appear immediately after the injury or may take hours or even days to develop.

They affect thinking, physical function, emotions, and sleep:

• Headache or pressure in the head — the most common symptom
• Dizziness or balance problems
• Nausea or vomiting
• Blurry or double vision
• Sensitivity to light or noise
• Feeling slowed down, foggy, or 'not right'
• Difficulty concentrating or remembering
• Mood changes — irritability, sadness, or anxiety
• Sleep disturbances — sleeping more or less than usual
• Brief loss of consciousness (not always present)

Symptoms of moderate to severe TBI

Moderate and severe TBIs involve more serious brain disruption and may include:

• Loss of consciousness for minutes to hours
• Persistent or worsening headache
• Repeated vomiting
• Seizures or convulsions
• Weakness or numbness in limbs
• Slurred speech or inability to speak
• Significant confusion or agitation
• One pupil larger than the other

Diagnosis

• Neurological examination — checks motor skills, coordination, reflexes, hearing, speech, memory, and mood
• Glasgow Coma Scale (GCS) — a standard tool used to assess level of consciousness and injury severity at the time of injury
• Cognitive tests — assess memory, concentration, reaction time, and problem-solving. Can be repeated over time to track recovery
• CT scan — the first imaging test used in emergency settings to detect bleeding, bruising, or swelling in the brain
• MRI scan — more detailed imaging used for less acute or complex cases; better for detecting subtle injury

In mild TBI / concussion, imaging is often normal — a normal CT or MRI does not mean the brain is unaffected.

Treatment

Rest: the first step

• Rest is the most important initial treatment for concussion
• Take 1–2 days off from work or school — most people do not need more than this
• Avoid activities that could cause another head injury while recovering
• Limit screens (phones, tablets, TV) in the first day or two if they worsen headache

Gradual return to activities

Recovery means being able to do your normal activities without symptoms returning. This is a step-by-step process:

• Step 1 — Complete rest until symptom-free
• Step 2 — Light aerobic activity (e.g., walking) — no resistance training
• Step 3 — Sport-specific or work-specific activities without risk of head contact
• Step 4 — Non-contact training drills or complex work tasks
• Step 5 — Full-contact sport or return to full work/school — only with medical clearance

Each step should take at least 24 hours. If symptoms return at any step, go back to the previous level.

Medicines

• Paracetamol (acetaminophen) or ibuprofen — for headache pain during recovery
• Avoid aspirin or other blood-thinning medicines unless prescribed — they may increase bleeding risk after head injury
• Do not take medicines that were not prescribed by your doctor for the concussion

Treatment for moderate to severe TBI

• Hospitalisation and intensive monitoring — to detect and manage bleeding, swelling, or raised brain pressure
• Surgery — may be needed to remove blood clots (haematomas), repair skull fractures, or relieve brain pressure
• Rehabilitation — a multi-disciplinary programme including physiotherapy, occupational therapy, speech therapy, and neuropsychology
• People who receive early care at a certified trauma centre tend to have the best outcomes

Complications

Post-concussion syndrome (PCS)

Some people have symptoms that last weeks, months, or longer after a concussion. This is called post-concussion syndrome.

• Persistent headaches
• Ongoing fatigue and sleep problems
• Difficulty concentrating or with memory
• Mood changes — depression, anxiety, irritability
• Dizziness or balance problems that continue

PCS is more common in people with previous concussions, older adults, and people with a history of anxiety or depression.

Second impact syndrome

A second concussion that happens before the brain has fully healed from the first — called second impact syndrome — can lead to rapid, life-threatening brain swelling. This risk is especially serious in teenagers and young adults.

• Never return to sport or high-risk activities before receiving full medical clearance

Long-term effects of moderate to severe TBI

• Chronic cognitive problems — memory loss, poor concentration, slow processing
• Epilepsy — seizures that develop after a head injury
• Motor problems — weakness, tremor, spasticity
• Personality and behaviour changes
• Depression, anxiety, and emotional dysregulation
• Increased long-term risk of dementia — research suggests moderate-to-severe TBI may be associated with a higher risk of developing dementia later in life

Chronic traumatic encephalopathy (CTE)

CTE is a progressive brain disease linked to repeated head impacts — most commonly seen in contact sport athletes and military veterans. It can only be confirmed after death by examining brain tissue.

• Symptoms may include memory problems, mood disturbances, confusion, and dementia
• CTE is associated with repeated exposure to head impacts over time — not necessarily a single concussion

Prevention of TBI

• Wear a helmet — always wear an appropriate, well-fitted helmet when cycling, motorcycling, skiing, or playing contact sports
• Wear your seatbelt — every trip, every passenger
• Prevent falls at home — remove trip hazards, use non-slip mats, install grab bars in bathrooms, ensure good lighting
• Use child safety equipment — car seats, stair gates, and window guards for young children
• Follow return-to-play rules — never allow an athlete to return to play on the same day as a suspected concussion
• Avoid alcohol when driving, cycling, or operating machinery

Recovery and long-term care

• Sleep well — adequate sleep is one of the most important factors in brain recovery
• Avoid alcohol — it slows brain healing and worsens symptoms
• Ease back into mental activity gradually — do not try to 'push through' brain fog
• Stay connected — support from family and friends is important for emotional recovery
• Tell your employer or school — adjustments can be made to help you recover fully before returning to full duties
• Keep all follow-up appointments with your doctor or brain injury specialist
• Track your symptoms and share them honestly with your healthcare team
• Seek specialist referral if symptoms persist beyond 4 weeks — a concussion clinic with an interdisciplinary team is ideal
• For moderate to severe TBI — long-term rehabilitation programmes may be required and should not be stopped prematurely

When to contact a doctor?

• Headache that gets worse and does not go away
• Repeated vomiting or seizures
• Loss of consciousness or cannot be woken up
• One pupil is larger than the other
• Slurred speech, extreme confusion, or agitation
• Weakness or numbness in arms or legs

Myths & Facts

Frequently Asked Questions