A concussion is a brain injury of such severity that it alters the way the brain functions for a short period of time. When jarred or shaken, the soft tissue of the brain can move around inside of the skull and knock into the hard bone. Bruising, torn blood vessels, and nerve damage can result.
A concussion is often caused by a blow to the head, face, neck, or elsewhere in the body where the force can be transmitted to the head (i.e. hitting your shoulder). It can also be caused by vigorous shaking. A person might suffer a concussion due to a fall, due to injuries resulting from a car accident, or due to any number of types of impact injuries, like a hard tackle in football or a high-hit or body-check in hockey.
People who get a concussion from participating in sports are at increased risk of getting at least one other concussion. Repeat concussions may occur from less severe impact and pose a greater risk for long-term effects.
Symptoms and Complications
Concussion symptoms range from unconsciousness to no outward symptoms at all. The most common immediate symptoms include confusion, dizziness, memory loss, ringing in the ears, clumsiness, double vision, and headache. The person may not be able to tell you what time of day it is or where they are. They often do not initially remember the events immediately preceding or following the accident. Speech may be slurred, and the person may vomit or feel nauseated or fatigued.
Over the course of hours or days, other symptoms may emerge: memory or concentration problems, sleep disturbances, changes in mood, blurred or double vision, and sensitivity to light and to sound. In many cases, the symptoms of concussion resolve after treatment and rest.
The symptoms of a concussion last less than 24 hours, and often less than 6 hours, after they first appear. If symptoms persist, then the brain injury is more severe. This is called post-concussion syndrome. The symptoms are similar to a concussion but may also include mood changes and irritability. It will typically resolve within a few days but may last several weeks.
A very young child may not be able to explain their symptoms, so adults should watch for signs of listlessness, unsteadiness, or changes in a child's mood (e.g., increased irritability) or patterns of eating or sleeping. A child should be closely monitored during the hours and days following a concussion. Ask a health care provider for more information about the signs to watch for and any special instructions to protect your child during recovery.
Making the Diagnosis
A doctor will examine a patient to assess their symptoms, checking pupil size and asking questions to determine the extent of confusion and memory loss. Further testing may be ordered, such as a CT scan, EEG, or MRI.
Treatment and Prevention
A concussion most often happens by accident, and not all causes can be prevented. To reduce your risk, protect yourself and your family from the most common dangers. Wear a seat belt whenever you ride in a car. Strap children into age- and size-appropriate safety seats. Wear protective gear whenever engaged in sports or active pursuits that pose injury risks (e.g., skating, bicycling, horseback riding). Wear shoes with low heels and good treads to prevent slips and falls.
Depending on the severity of the concussion, a patient may be ordered to rest (no exercise, playing, or computer games). Returning to activities before you are completely better can actually make things get worse, and you may have symptoms for longer. Athletes who experience a concussion should return to their sport only after they are symptom-free, and they should gradually increase activity only as long as they continue to be symptom-free. Medication may be recommended to treat symptoms such as headache, pain, or nausea.
Symptoms of concussion may linger for months or longer after injuries have healed. In post-concussion syndrome, a person may continue to experience headaches, dizziness, fatigue, and changes in mood, sleep, and memory. Since these symptoms are common in everyday life, it can be difficult to know if they were caused by the concussion. Repeated concussions may lead to permanent neurological damage.