Concussion

The first international conference on concussion in sport defined sports concussion as ‘a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces’ (Aubrey et al., 2002).

Concussion occurs when the brain is rapidly ‘shaken’, and the condition can be present even though the patient is still conscious. Often, the period of unconsciousness is so brief that it may go unnoticed, and there is only transient memory loss. This is frequently the case with contact injuries where an athlete collides with another and hits his or her head. Clinically concussion may occur from a direct blow to the head or from impulsive force which is transmitted to the head from other regions of the body. There is an impairment of neurological function which is short lived and resolves spontaneously. In sport concussion there is a functional disturbance rather than structural damage and as such neuroimaging is normal (McCrory et al., 2005).

Concussion classification and evaluation

Sport concussion may be classified as simple or complex. Simple concussion is the most common type and this typically resolves without complication in 7−10 days. Formal neurophysiological screening is not normally required but medical evaluation should still be made. Training and playing are limited while the player is symptomatic, and return to sport is graded. Complex concussion is present when symptoms persist or recur, and this grouping includes those who suffer a number of concussions over time. Such symptoms include convulsions, prolonged loss of consciousness (greater than 1 minute) or prolonged cognitive impairment. Symptoms may be seen at rest or with exertion. Formal neurophysiological assessment is normally required.

The Glasgow Coma Scale (see below) is traditionally used to assess head injury. However, due to the mild nature of sport concussion this type of scale is no longer considered an appropriate evaluation measure for sport concussion (McCrory et al., 2005). A sport concussion assessment tool (SCAT) was developed at the International Conference on Concussion in Sport, Prague 2004, and updated at the Zurich Conference 2008 (McCrory et al., 2009). Two forms are available, the Pocket SCAT2 (Table 6.7) for general usage and the full SCAT2 for medical and health professionals.

Table 6.7 Pocket SCAT2

Concussion should be suspected in the presence of any one or more of the following symptoms (such as headache) or physical signs (such as unsteadiness) or impaired brain function (e.g. confusion) or abnormal behaviour.
1. Symptoms
Presence of any of the following signs and symptoms may suggest a concussion:
Loss of consciousness Seizure or convulsion Amnesia Headache ‘Pressure in head’ Neck pain Nausea or vomiting Dizziness Blurred vision Balance problems Sensitivity to light Sensitivity to noise	Feeling slowed down Feeling like ‘in a fog’ ’Don’t feel right’ Difficulty concentrating Difficulty remembering Fatigue or low energy Confusion Drowsiness More emotional Irritability Sadness Nervous or anxious
2. Memory function
Failure to answer all questions correctly may suggest a concussion: What venue are we at today? Which half is it now? Who scored last in this game? What team did you play last week/game? Did your team win the last game?
3. Balance testing
Instructions for tandem stance Now stand heel-to-toe with your non-dominant foot in back. Your weight should be evenly distributed across both feet. You should try to maintain stability for 20 seconds with your hands on your hips and your eyes closed. I will be counting the number of times you move out of this position. If you stumble out of this position, open your eyes and return to the start position and continue balancing. I will start timing when you are set and have closed your eyes. Observe the athlete for 20 seconds. If they make more than 5 errors (such as lift their hands off their hips; open their eyes; lift their forefoot or heel; step, stumble or fall; or remain out of the start position for more than 5 seconds) then this may suggest a concussion. Any athlete with a suspected concussion should be IMMEDIATELY REMOVED FROM PLAY, urgently assessed medically, should not be left alone and should not drive a motor vehicle.

The Pocket SCAT2 consists of three sections: (1) symptoms, (2) memory function and (3) balance testing, which enable the examiner to determine if concussion is suggested. If the test is positive (concussion suggested) the athlete should be immediately removed from play and medical assessment made.

For the full SCAT 2 (http://www.sportalliance.com/Images/Sport%20Safety/SCAT2.pdf) the medical or health professional assesses the patient over eight domains which are colour coded for ease. The scores obtained on these domains are put together to give an overall score, and normative data for this score are developed. The SCAT2 domains are:

The final section of the SCAT2 gives athlete information with recommendations for a graded return to play (see Table 6.8). Concussion injury advice is presented as a cut-off section to be given to the concussed athlete. The SCAT2 documents are available on several websites. The full version is available at http://bjsm.bmj.com/cgi/reprint/43/Suppl_1/i85. The pocket SCAT2 is available at http://www.sarugby.co.za/boksmart/pdf/PocketSCAT2%20final.pdf.

Table 6.8 Graded return to play following sport concussion

To form a baseline assessment the SCAT2 should be given to each athlete at the beginning of the season and results recorded for normal activity.

Multiple concussion incidents

The cumulative effects of concussion are important in sports such as boxing, steeplechase and football (Corsellis, 1974; Sortland, Tysvaer and Storli, 1989; McLatchie, 1993). EEG disturbances due to neuronal damage through repeated trauma are seen, especially where a series of EEGs are performed. In addition, neuropsychological performance is impaired, often in the presence of a normal CT scan (McLatchie, Brooks and Galbraith, 1987).

Failure to allow adequate recovery from a concussion incident may result in second impact syndrome (SIS), where a second blow to the head causes further swelling and bleeding. The second blow may be minor and may not appear sufficient to affect the brain. However, the two combined insults cause rapid and profuse swelling. Athletes usually develop respiratory failure and collapse. The mortality rate for this condition is as high as 50% (Cantu, 1998).

Because of the risk of persistent swelling or late bleeding, the return to sport should be delayed following multiple concussion. All athletes sustaining this type of injury should be given a head injury advice card (Table 6.9). Medical examination is essential where there is a failure to remember the event which gave the head injury however minor it may seem. All cases where consciousness has been lost for longer than 3 minutes warrant x-rays of the skull and cervical spine and/or neuroimaging (Buxton and Firth, 1999).

Table 6.9 Care of athletes who have sustained a head injury

Intracerebral lesions

The danger from any head injury is an expanding intracranial lesion resulting from a torn blood vessel, causing epidural (extradural) haemorrhage, subarachnoid haemorrhage or subdural haematoma (Fig. 6.1), so assessment is vital.

Figure 6.1 Intracranial haematoma.

These conditions are indicated by an alteration in consciousness (lucid state) and the signs and symptoms shown in Table 6.10. Normally, the intracranial pressure is 4–15 mmHg and an intracranial pressure of 40 mmHg will cause neurological impairment.

Table 6.10 Signs of an expanding intracranial lesion

After Magee (2002).

After such an incident, an athlete should only be allowed to continue providing he or she did not lose consciousness. Tests such as the ability to stand up without assistance, stand alone with eyes closed and run to a mark and change direction rapidly are all useful for initial assessment.

The first decision to be made with an unconscious athlete is whether he or she is still breathing. If not, resuscitation must be started immediately. If the athlete regains consciousness, the level of potential damage should be assessed. Response of the eyes, body movements and speech all give clues to the level of consciousness, and the Glasgow Coma Scale is the standard examination method.

The Glasgow Coma Scale

The Glasgow Coma Scale (Teasdale and Jennett, 1974) is a series of tests that are given a numerical value which can then be used to objectify an athlete’s state of consciousness (Table 6.11). The scale also forms domain 3 of the SCAT2 evaluation. The first test relates to the eyes, and determines whether the athlete opens the eyes spontaneously or in response to sound (verbal command) or pain. Opening the eyes to verbal command merely means that the person has registered sound; it does not imply that they necessarily understand the command. The second test is of verbal response, and assesses the athlete’s reaction to simple questions such as ‘where are you’ or ‘what is your name’. The test assesses whether the athlete is aware of him/herself and the environment. The third test is of motor response. The maximum score is 6 if the athlete is able to perform actions correctly to verbal commands such as ‘move your arm’. If the athlete fails to respond, a painful stimulus is applied by the practitioner pressing their knuckles into the athlete’s sternum, or pressing the athlete’s fingers together around a pen. Painful stimuli to the face or palm of the hands should be avoided as these can give reflex eye closing and hand closing respectively (Magee, 2002). Where reflex responses alone result, flexion of the arms and hands together with adduction of the upper limb and extension of the lower limb with plantarflexion of the feet (decorticate posturing) indicates a lesion above the red nucleus. Extension of the arms with pronation of the forearm (decerebrate posturing) indicates a lesion of the brainstem. The time of the test should be noted and the test repeated every 15–30 minutes to note any degeneration of results.

Table 6.11 The Glasgow Coma Scale

Where the score is between 3 and 8 on the coma scale, emergency care is required immediately as a severe head injury is present. Those with scores of 9–11 are considered to have a moderate head injury, and those with a score of 12 or higher are considered to have a mild head injury.

Caution must always be exercised with head injuries. Unfortunately, the practitioner or coach who has to decide whether to allow an athlete to continue playing has no way of knowing if secondary brain damage is going to develop. At the time of injury, bleeding may have occurred which could accumulate and give rise to a subdural haematoma.

An athlete who remains unconscious should be placed in the recovery position until an ambulance is available to take him or her to hospital. If there is bleeding or discharge from an ear, the athlete should be turned so that the affected ear is dependent. Nothing should be given by mouth, and the athlete should not be left unattended. Testing for responses should continue regularly (every 10 minutes or more frequently) and any changes in the athlete’s condition should be recorded.