The brain is safely encased within the hard bony skull and further protected by surrounding fluid which acts as a shock absorber. Despite these protective mechanisms, brain injury can still occur even if there is no penetration of the skull. This is known as traumatic brain inury and there are different grades of severity. A concussion is a mild traumatic brain injury and can occur for a host of reasons.
Read more on traumatic brain injury.
What happens in a concussion?
A concussion is where there is a disruption in the normal activity of the brain usually due to an injury. The disturbance in brain function is temporary but there can be complications which may arise up to years after the concussion. Overall concussions are uncommon and most of the time it is not serious. Rest for a few hours is sufficient to overcome the disturbance although some people may need days or weeks to recover.
Although a concussion does not result in permanent brain damage, the effects can be quite severe in the short term. It depends on the extent of the brain injury. Very mild concussions may cause little to nor symptoms and many people do not realize that they have a concussion in these cases. With a more severe concussion that may be disturbances in the senses, impairment of balance and coordination, confusion and even loss of consciousness.
What Causes A Concussion?
A blow to the head is the more common cause of a concussion. It may arise with a fall, contact sports injury and assault. Concussions are also common in motor vehicle collissions even when there is no obvious head injury. The reason for a concussion in these cases is due to a violent whipping of the neck where the head moves front and then back rapidly. Whiplash commonly accompanies the concussion in these cases.
Read more on whiplash and concussions.
Headache and Head Pressure
A headache is a common sign of a concussion and it can vary in the nature of the pain, severity and duration. Headaches may not always occur in a concussion. Some people just experience a pressure sensation in the head which they may also describe as congestion. At other times there may be no headache. A worsening headache may be a sign of raised intracranial pressure (ICP) which is a medical emergency.
Lightheadedness and Dizziness
Dizziness is another common symptoms. Sometimes it may be a mild lightheaded feeling whereas at other times there may be overt dizziness where there is a sensation of spinning around. The dizziness can be short lived or persistent for hours and even days. When the dizziness is worsening along with a worsening headache then raised intracranial pressure must be suspected.
Poor Balance and Coordination
Due to the dizziness and disturbance of normal neurologic function, many people with a concussion experience poor balance and coordination. This may last anywhere from a few minutes to several days in more severe cases. Coupled with the other symptoms of a concussion, it may appear that a person in dazed. There is a risk of falling repeatedly and bed rest is strongly advised. However, this quickly resolves without permanent effects.
A range of visual disturbances can occur with a concussion. Many people report stars and flashing lights in their field of vision with no physical source for these shapes and lights. There may also be blurred or double vision. It is usually momentary and eases quickly provided that there are no complications. However, if there is an eye injury and the symptoms persist then there could be eye-related causes like a detached retina.
Ringing Sound in Ears
A ringing sound in the ears without any physical source is another possible symptom that arises with a concussion. This is known as tinnitus and some people may experience it as a roaring sound. As with visual disturbances, the ringing sound usually resolves fairly quickly.
Nausea and Vomiting
Nausea may also occur with a concussion and sometimes there may even be vomiting. While the nausea quickly resolves, continuing nausea and vomiting could be a serious sign. When it occurs with a worsening headache and dizziness, then it points to raised intracranial pressure which requires immediate medical attention. Alterations in blood glucose, blood pressure and hormone levels may also be responsible for the nausea.
Confusion and Amnesia
It is not uncommon for there to be confusion immediately after the traumatic event as a result of the concussion. A person may be unaware of where they are or what happened. Sometimes a person with a concussion may not be able to remember their name, home address or even recognize certain known people. However, this is short lived and resolves within minutes. Amnesia may occur where a person cannot remember the traumatic event specifically and a short period of time before and after it. This amnesia of the event can persist for long periods.
As with impairement of other brain functions, a person may experience slurred speech. This can appear similar to slurring of speech as is seen with inebriation. It may be further exacerbated by an inability to construct sentences or recall the correct words. However, this is temporary and more likely to occur immediately after the event. When slurring of speech persists then further investigation is necessary.
Fatigue, which is extreme tiredness, is another sign of a concussion. It arises immediately after the traumatic event and can persist for days or even weeks. Although rest may help to relieve the fatigue in most instances, some people experience ongoing fatigue despite adequate rest. It may continue as part of post-concussion syndrome which can continue for years but eventually it resolves.
Loss of Consciousness
Loss of consciousness does not always occur with a concussion. However, when it does occur after a traumatic head injury it is a clear indicator of a concussion. This loss of consciousness can occur for few seconds or minutes to several hours and sometimes even days or months (coma). The latter is more of a concern as it may be due to severe brain injury with permanent disabilities and in the worse case scenario it can progress to death.
Other Signs and Symptoms
There are several signs and symptoms may also be present. This includes light sensitivity, difficulty concentrating, memory problems, alterations of taste and smell and sleep disturbances. Sometimes there may even be irritability and personality changes, ongoing anxiety and depression which may all be part of post-concussion syndrome.