MILD HEAD INJURY (CONCUSSION)
Concussion, also known as mild traumatic brain injury, is the most widespread and least severe of traumatic brain injuries. It results in temporary, short-lived failure of mental function and is most commonly caused by injuries involving a direct blow to the head or acceleration / deceleration forces.
Signs of mild head injury (concussion)
Signs of concussion include:
- Loss of consciousness for no more than thirty minutes.
- Dizziness and confusion.
- Visual problems, such as seeing stars or flashes of light.
Amnesia (memory loss) is one of the most common symptoms of concussion and may be either retrograde (when you forget memories previous to the injury) or anterograde (when you lose memories formed after the incident). In most cases amnesia is anterograde and is sometimes referred to as post traumatic amnesia or PTA. This form of amnesia makes it difficult to form and retain new memories. Amnesia is sometimes not noticeable until a few days or even a week after an injury or accident. Anterograde amnesia is exemplified by the following example of a sports player who retains detailed memories of what was happening during a game before an injury, but who has no recollection of what happened subsequent to the incident.
A patient who has suffered concussion may exhibit signs of confusion. For example, they may ask the same questions over and over again and appear disorientated. If patients show signs of focal neurological deficits (problems with the nerves that affect specific areas of the face or brain) this may suggest that an area of the brain isn’t functioning normally.
In many cases of concussion there is no damage to the structure of the brain, so the patient’s condition stays the same or improves over the next few days. However, damage to the brain can trigger pathological processes with symptoms becoming worse. In more severe or complex cases of concussion the patient’s condition usually gets worse during the next few days after injury; complex cases can result in long-term deficits. If a patient displays a decreasing level of consciousness this may indicate a more severe head injury. The following symptoms may also indicate an increase in pressure to the skull (known as intracranial pressure:
- Persistent vomiting.
- Increased confusion.
- Feeling drowsy.
- Tinnitus (ringing noise in the ears).
- A headache that is getting progressively worse.
- Difference in the size of the pupils.
Over the course of the next 72 hours after damage it is possible that axonal injury (injury to an axon, the nerve fibre) is progressing, which may result in the axon becoming severely damaged or even killed by fluctuations in the ions.
The most common error for people who have suffered a concussion is avoiding their doctor or not seeking medical help when symptoms grow worse over the course of the initial 72 hours. It is common for athletes and elite sports players to be monitored by their teams. However, many patients who are involved in accidents may be told to go home without any arrangement for further checks and this can be dangerous. Symptoms can often progress quickly and may not appear for at least 2 days after an incident. Even the most innocuous knock can be potentially serious.
If a patient has suffered a concussion the day before and they do not have a clear memory of the time between yesterday and today, this indicates post traumatic amnesia and the risk of long-term problems is consequently higher.
Most of the research carried out on concussions focuses on young, fit people. Those who are over the age of 40 have a higher chance of developing long-term problems because their brains are not able to regenerate as quickly or effectively. Women tend to be more severely affected by concussion than men.
Grades of mild head injury (concussion)
Concussion is classified using a grading system from I to V, as follows:
- Grade I: this is the mildest form of concussion and usually causes short-term confusion.
- Grade II: this is where concussion causes confusion and short-term anterograde amnesia.
- Grade III: this is where concussion causes confusion, short-term anterograde amnesia, unconsciousness (for no more than five minutes) and retrograde amnesia.
- Grade IV: this is where concussion causes confusion, short-term anterograde amnesia, retrograde amnesia and loss of consciousness for between five to ten minutes.
- Grade V: this is the most severe form of concussion. It causes all of the symptoms listed above in addition to a loss of consciousness for more than 10 minutes.
It is believed that grade II and III concussion can cause permanent brain damage and therefore it is easy to see how a seemingly modest brain injury can result in serious consequences when symptoms last for longer than fifteen minutes.
What do the grades mean for athletes?
- Grade I: the player can return to playing contact sports within 20 minutes.
- Repeat grade I concussion (the player has already suffered a grade I concussion in the past).
- Grade II: the player can return to contact activities 1 week after displaying no symptoms.
- Repeat grade II: the player can return to contact activities after one month of displaying no symptoms.
- Grade III: a player can return to contact activities within 1 month.
- Repeat grade III: the player will be advised not to return to contact activities for the duration of the season.
Players who suffer repeat concussions are advised to undergo regular tests and follow medical advice. In most cases symptoms of a concussion subside after 72 hours, though this is not always the case.
What is post-concussion syndrome?
Post-concussion syndrome occurs when a patient experiences symptoms for a long period of time after the initial incident. This may include headaches, dizziness, heightened sensitivity to light and sound, difficulty with memory and a lack of concentration. Such symptoms can also contribute to anxiety and depression. In most cases symptoms reach a peak after 6 weeks, though it is possible to experience them for a year or even longer. It is more common for children to suffer severe signs of post-concussion syndrome compared to older patients. Rest combined with physiotherapy is the best method of treatment.