Brain Injury
Damage to the brain from trauma or other harm
Quick Facts
- Type: Neurological injury
- Main types: Traumatic and acquired (non-traumatic)
- Common causes: Falls, crashes, sports, lack of oxygen
- Seek urgent care: After any significant head injury
Overview
A brain injury is any damage to the brain that disrupts how it works. It is broadly divided into two groups. A traumatic brain injury (TBI) is caused by an external force, such as a blow, jolt, or penetrating wound to the head. An acquired (non-traumatic) brain injury results from an internal event, such as a stroke, lack of oxygen, infection, or a tumor.
Brain injuries range widely in severity. A mild injury such as a concussion may cause temporary symptoms that fully resolve, while a severe injury can cause lasting changes in movement, thinking, behavior, and the senses. Because the brain controls so many functions, the effects depend heavily on which areas are damaged and how badly. Prompt recognition and care can reduce further harm and improve recovery.
Symptoms
Symptoms depend on the severity and location of the injury and may appear immediately or develop over hours. Common signs include:
- Headache, dizziness, or loss of balance
- Confusion, memory problems, or difficulty concentrating
- Nausea or vomiting
- Brief or prolonged loss of consciousness
- Sensitivity to light or noise, blurred vision, or ringing in the ears
- Mood changes, irritability, or sleep problems
- In severe cases: repeated vomiting, worsening confusion, seizures, weakness, slurred speech, unequal pupils, or clear fluid from the nose or ears
Severe symptoms, or any worsening after a head injury, are a medical emergency and require immediate care.
Causes
Brain injuries can result from many events:
- Falls: A leading cause, especially in young children and older adults.
- Motor vehicle and bicycle crashes.
- Sports and recreation: Contact sports and high-impact activities.
- Violence: Assaults, gunshot wounds, and abusive head injury.
- Blasts: Explosions, particularly in military settings.
- Non-traumatic causes: Stroke or bleeding in the brain, lack of oxygen (for example after cardiac arrest or near-drowning), severe infections such as meningitis, and tumors.
Risk Factors
- Very young children and older adults (higher fall risk)
- Participation in contact or high-impact sports
- Risky driving, not wearing seatbelts, or not using helmets
- Previous brain injury or concussion
- Alcohol or substance use
- Conditions that increase fall, stroke, or bleeding risk
Diagnosis
Doctors assess brain injury with examination and, when needed, imaging:
- Neurological exam: Checking alertness, memory, speech, strength, coordination, reflexes, and the pupils, often using a standard scale of consciousness.
- CT scan: The fastest way to find bleeding, swelling, skull fractures, or bruising after trauma.
- MRI: Provides detailed images for less obvious or longer-term injury.
- Cognitive and balance testing: Used especially to evaluate concussion and track recovery.
- Monitoring: In severe cases, pressure inside the skull may be measured in an intensive care setting.
Treatment
Treatment depends on severity and the type of injury.
- Mild injury (concussion): Physical and mental rest, gradual return to activity, and treatment of symptoms such as headache. Most people recover within days to weeks.
- Moderate to severe injury: Emergency care to keep oxygen and blood pressure stable, control swelling, and prevent further damage; medicines for swelling, seizures, or pain.
- Surgery: May be needed to remove blood clots, repair the skull, or relieve pressure inside the head.
- Rehabilitation: Physical, occupational, speech, and cognitive therapy help recovery of movement, communication, and thinking.
Long-term care and support may be needed after a severe injury, and recovery can continue for months or longer.
Prevention
- Wear seatbelts and use age-appropriate child car seats
- Wear helmets for cycling, motorcycling, skiing, and contact sports
- Reduce fall hazards at home, especially for young children and older adults
- Follow concussion guidelines and do not return to play too soon after a head injury
- Avoid driving or operating machinery under the influence of alcohol or drugs
- Use safety gear and follow safety rules at work and in sports
When to See a Doctor
Any significant head injury should be evaluated. Seek emergency care immediately if a person has:
- Loss of consciousness, repeated vomiting, or a seizure
- Worsening or severe headache, confusion, or unusual drowsiness
- Weakness, numbness, trouble speaking, or loss of coordination
- Unequal pupils, slurred speech, or clear fluid draining from the nose or ears
- A young child who will not stop crying, will not eat, or seems unusually sleepy after a head injury
Frequently Asked Questions
What is the difference between traumatic and acquired brain injury?
A traumatic brain injury is caused by an external force such as a blow or jolt to the head. An acquired or non-traumatic brain injury comes from an internal event such as a stroke, lack of oxygen, infection, or tumor.
How do I know if a head injury is serious?
Warning signs include loss of consciousness, repeated vomiting, worsening or severe headache, confusion, seizures, weakness, slurred speech, unequal pupils, or fluid draining from the nose or ears. Any of these means you should seek emergency care right away.
How long does it take to recover from a concussion?
Most people recover from a concussion within a few days to a few weeks with rest and a gradual return to activity. Some have symptoms that last longer, and returning to sports or strenuous activity too soon can slow recovery.
Can a brain injury cause lasting effects?
Mild injuries usually resolve fully, but moderate to severe injuries can cause lasting changes in movement, thinking, memory, mood, or the senses. Rehabilitation therapies help many people regain function over time.
When should a child with a head bump see a doctor?
Seek care if a child loses consciousness, vomits repeatedly, has a seizure, will not stop crying, refuses to eat, seems unusually sleepy or confused, or has worsening symptoms. When in doubt, have the child evaluated.
References
- Centers for Disease Control and Prevention (CDC). Traumatic brain injury and concussion.
- MedlinePlus, U.S. National Library of Medicine. Traumatic brain injury.
- Mayo Clinic. Traumatic brain injury — Symptoms and causes.
- National Institute of Neurological Disorders and Stroke (NINDS). Traumatic brain injury.