Some concussions cause loss of consciousness but most do not. It is possible to sustain a mild concussion without realising it.
Most people usually recover fully after a concussion, while some can experience longer-lasting problems.
It is important to avoid head injuries because there is evidence that repeated concussions might cause long-term problems with mental abilities and trigger dementia. This appears to be a risk for professional athletes who sustain frequent episodes of severe concussion.
CausesYour skull provides a protective casing for your brain. However, a blunt-force blow to the head and upper body can cause the brain to move suddenly and violently, colliding into that protective casing, resulting in injury to the brain. Sudden acceleration or deceleration of the head, such as that caused by a car crash or being shaken forcefully, can also result in brain injury.
These injuries cause loss of brain function, usually temporarily, which manifests as the signs and symptoms of concussion. Severe brain injury may result in bleeding in or around the brain. Brain-related bleeding can be life-threatening, which is why people with a concussion should be monitored after the injury and receive emergency care if symptoms worsen.Concussions are a common occurrence in combat sports (such as boxing and martial arts), contact sports (like rugby and football) and cycling accidents. Accidental falls, especially in young children and the elderly, and motor vehicle accidents are also common causes of concussion. Concussion can also occur in victims of physical violence or abuse.
Signs and symptoms
Concussion symptoms can be mild or severe. Severe concussion may result in prolonged unconsciousness and may require emergency care.
The most common signs and symptoms of concussion are:
- Feeling stunned or dazed
- Confusion, e.g. a delay in answering questions
- Ringing in the ears
- Vision disturbances (double or blurred vision or ‘seeing stars’)
- Memory loss (amnesia) that improves within a few hours.
Medical care should be sought if symptoms worsen or if there are more serious symptoms such as:
- Loss of consciousness, however brief
- Repeated vomiting
- Slurred speech
- Confusion or disorientation
- Convulsions or seizures
- Memory loss, e.g. being unable to remember what happened before or after the concussion
- Changes in mood or behaviour, e.g. unusual irritability
- Drowsiness or difficulty staying awake
- A headache that gets worse and does not go away
- Weakness, numbness, or lack of physical co-ordination.
Symptoms of a concussion may be delayed and not appear until days or weeks after the injury.
Concussion can be less obvious in infants and young children. A change in normal behaviour after a head injury, e.g. excessive crying, changes in feeding or sleeping habits, or reduced interest in people or favourite toys are key signs to look out for.
To diagnose concussion a healthcare professional will ask about the injury and conduct a physical examination. They are likely to check vision, hearing, balance, co-ordination, and reflexes to see if your nervous system is functioning properly. They may also ask questions to check thinking skills, concentration, and memory (including recollection of things that happened immediately before or after the injury).
In some cases, such as in people with severe concussion symptoms that are getting worse, a computed tomography (CT) or magnetic resonance (MRI) scan may be used to check for bleeding or swelling in the brain and for skull fractures.
Careful monitoring (usually for 48 hours) may be required after a concussion to ensure symptoms don’t get worse or because the symptoms of concussion could indicate brain-related bleeding.
Rest is important because it helps the brain to recover from a concussion. This may include limiting physical activities and mental activities that involve a lot of concentration, such as studying, computer work, or video games. These activities may exacerbate concussion symptoms such as headache or tiredness.
Someone who has had a concussion should not return to sporting or vigorous activity for at least three weeks. After this time if you have no symptoms of your injury and your doctor has said you can, you can resume physical activities.
Self-care for concussion symptoms includes:
- Have someone to stay with you for the first 48 hours after the injury.
- Get plenty of rest and avoid stressful situations.
- Apply a cold compress to the injury to reduce swelling.
- Take paracetamol to relieve headaches. Do not use non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or aspirin, which can increase the risk of internal bleeding.
- Avoid drinking alcohol or taking recreational drugs.
- Return to school or work only when you feel that you have completely recovered.
Taking the following precautions may help to minimise the risk of concussion:
- Wear a helmet or protective head gear when bicycling, motorcycling, snowboarding or engaging in any recreational activity that may result in head injury
- Wear a seat belt when driving
- At home, keep floors and staircases free of anything that might cause someone to trip and fall. Block off access to staircases to reduce the risk of head injuries to small children
- Clean up spillages to prevent someone slipping and falling
- Exercise regularly to strengthen your leg muscles and improve balance.
Further information and support
Freephone (24/7): 0800 611 116
Web page: www.healthline.govt.nz
Mayo Clinic (2017). Concussion (Web Page). Rochester, NY: Mayo Foundation for Medical Education and Research. [Accessed: 19/09/18]
Ministry of Health (2018). Head injury and concussion (Web Page). Wellington: New Zealand Government Ministry of Health. https://www.health.govt.nz/your-health/conditions-and-treatments/accidents-and-injuries/head-injury-and-concussion [Accessed: 19/09/18]
NHS (2015). Concussion (Web Page). Redditch: National Health Service (NHS)
England. http://www.nhs.uk/conditions/Dehydration/Pages/Introduction.aspx [Accessed: 19/09/18]
NHS inform (2018). Concussion (Web Page). Glasgow: National Health Service Scotland. https://www.nhsinform.scot/illnesses-and-conditions/injuries/head-and-neck-injuries/concussion#introduction [Accessed: 19/09/18]
O’Toole, M.T. (Ed.) (2013). Brain concussion. Mosby’s Dictionary of Medicine, Nursing & Health Professions (9th ed.). St Louis, MI: Elsevier Mosby.
Last udpated: September 2018