Concussion: Hits to the Head

Watching the boxing at the Commonwealth Games as a volunteer medic, two thoughts were going through my head.  The first was ‘please stand up’ and the second was about how important concussion is becoming in the minds of athletes, coaches and society in general.  In the US 1.7 million people sustain a traumatic brain injury each year and this results in 275000 hospitalisations.  This resulted in a total cost of around $60 billion (US) in 2000 from both direct costs, such as medical care, and indirect costs, such as time out from work, from concussion injuries.

Concussion is a traumatic brain injury, the word coming from the Latin ‘to shake violently’.  This is usually sustained after an impulsive blow is transmitted to the head through a direct or indirect force to the head or neck.  Symptoms that a patient can demonstrate include physical or behavioral changes e.g. losing consciousness or being irritable, impairment of thinking e.g. reaction time slowed or feeling like you are in a fog, problems with sleeping,  and emotional instability.  At a microscopic level it is currently thought that nerves get stretched during the injury.  This stretching make the nerves become more permeable and they subsequently take on excess fluid and swell resulting intimately in disruption of the casing around the nerve, the nerve membrane.  In addition the blood flow to the brain is reduced and there are abnormal peaks of electrolytes such as calcium and potassium in the brain fluid.  The patient will develop swelling of the brain as it relies on its own regulatory mechanisms to compensate for the additional stresses associated with this swelling.  Over the next few days the brain has an altered metabolism, a state which can last up to ten days. The cumulative effect of these episodes over a long period of time creates changes in brain cell function resulting in proteins being accumulated within the cell.  As the volume of these proteins increases within each brain cell the patient develops whats referred to as a “chronic traumatic encephalopathy”.  In more simple terms a chronic form of brain damage.  This insidious encephalopathy is now causing causing great concern for the NFL in America and is thought to affect up to 17% of players who experience repeated concussions.

The important point to note here is concussion can present with or without actually losing consciousness.  The onset can be very rapid and resolution can be spontaneous.  Meaning it is not always identified after a head knock.  Only about 10% of concussion involve a loss of consciousness so assessing whether or not the person was knocked out is not always good indicator of how well they will do post concussion.  Medical teams have to start relying on other symptoms of concussion to assess a players suitability to return to the field or play the following week.  These symptoms are largely self reported and rely on players assessing their own progress.  They include things such as such as headaches, amnesia, and learning difficulties.

The objective signs of a concussion are often subtle and therefore may be missed by coaches, athletes and referees.   Even so,  players need to be educated about how to identify and manage symptoms of a concussion during a game or at training.  The Australian Rugby Union has recently moved to use a ‘Blue Cards’ system.  In matches of players U13 or above, referees will now produce a blue card if signs of concussion are demonstrated.  Medical staff then assess the patient and a mutual agreement is made between the referee and medical staff on how to proceed with the players best interests in mind.  If the referee believes the patient needs to go off, they have the final say however.  This obviously places a lot of pressure on the referee to make a call, but it does demonstrate the importance of not continuing to play in the presence of a concussion.  This is just one example of how various sporting codes have struggled to deal with both management of the initial injury and the players subsequent return to play.

The worst thing an athlete can do is return to play without having had their symptoms resolve.  If they are under twenty and they return to play before a concussion resolves there is a higher than expected mortality rate during subsequent injuries.  This is known as the “Second Impact Syndrome” and is controversial.   The theory is that due to the altered brain metabolism mentioned previously once swelling of the brain has occurred,  there are massive electrolyte imbalances in the fluid surrounding the brain making it more vulnerable as it recovers.  A second hit will cause the brain to lose the ability to regulate its own healing, leading to a massive increase in the swelling of the brain.  The brain only has so much room to swell into, leading to cell death and patient death within 2-5 minutes. Much more commonly seen in patients who sustain a second concussion having not yet recovered from the first is that they will have a much more prolonged recovery, thought to have similar features to a less severe form of Second Impact Syndrome.   Finally an athlete with multiple concussions risks developing the condition of chronic traumatic encephalopathy, the so called ‘punch drunk’ syndrome seen in boxers.  Its important to note however that this is not something restricted only to hard core contact sport.  Research from the US has shown that even a mild hit to the head in NFL players who experience no concussive symptoms can result in poorer results on neurological testing creating a “sub concussion syndrome” which can in some cases also lead to the chronic traumatic encephalopathy, so these overlapping episodes can contribute to cell death and brain damage.

So then, can we just look at the brain to diagnose concussion? Unfortunately, medical imaging is not always useful in a concussion as the damage is at a microscopic cellular level and as such the the brain scan often looks normal but the headaches and learning difficulties continue.  Imaging can be useful however to rule out other significant diagnoses such as bleeding in the brain.

Management is two pronged and requires treatment of both the acute concussion and the persistent post concussion symptoms.  Acutely, the patient is immediately removed from the field of play.  The concussion must have subsided prior to return to play.  Tests such as the SCAT5 is important to facilitate concussion assessment on field and should be administered by a medical professional.   Following diagnosis the best treatment is resting the brain, both from both physical and cognitive activity.  This means that the athlete must avoid training as well as other activities such as school work, video games, reading and anything that requires higher orders of thinking.  This is an important consideration with young people who play contact sports and risk time out of school or work if concussed.  The good news is that around 80% of cases will resolve within 10 days.  Only 10-20% of cases will persist weeks to months.

But when can a player with a head knock return to play?  It is not as simple as being symptom free many of the symptoms are considered “non-specific” for example headache occurs in the the general population, non concussed athletes those who have experience a concussion.  As a general rule players can expect to be out of play and training for 8-10 days after a concussion.  During this period a graded return to play can be pursued.  This consists of a six step process which has been adopted by many sporting bodies after being published in a Consensus Statement on Concussion in Sport. Each step must be followed for at least 24hrs and the athlete must remain symptom free for this entire period before being able to progress to the next stage.  Importantly if symptoms reoccur during the program the athlete returns to step one and re starts the program.

The steps are:

  1. No activity with aim of recovery
  2. Light aerobic exercise, 70% of maximum permitted heart rate, no weight training, aiming to increase heart rate
  3. Sport specific exercising, drills no head impact aiming to add movement
  4. Training in non-contact exercises, may start weight training aiming to improve thinking and coordination
  5. Full contact step – this requires medical assessment and clearance and progression to normal training with the aim to restore confidence
  6. Normal game play

The concussion guidelines at the Australian Rugby Uuion state that adults over 19 have a minimum period of 12 days off and athletes under 18 have a minimum 19 days off.  They require a player to have three assessments following the injury- 1. At the time of injury, 2. Three hours following the injury and 3. “2 sleeps” or 48 hours after the injury.  A concussion diagnosis can be made at any time during this period.  During the enforced recovery time players should be encouraged to reduce nicotine, alcohol and caffeine intake as well as avoiding daytime napping.  Education on the best ways to cope with sleeping disorders is important and they emphasise avoiding the use of sleeping tablets.  If an athlete feels low in mood antidepressants can be utilised under supervision of a medical doctor.

A final note on my experience at the boxing – even amateur boxers have been shown to have subtle cognitive impairments following a bout and this is demonstrated by decreases in reaction time on cognitive testing.  This is similar to the sub-concussion syndrome described above which may not be recognised at the time.  On the up side there appears to be a very low level of chronic traumatic brain injury in amateur boxers with no strong evidence for an association between chronic traumatic brain injury and amateur boxing.

  • GPearls on the GC
    • Concussion can occur without loss of consciousness
    • SCAT5 is not what you think it is
    • There are 6 steps to a happy brain
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