The purpose of this chapter is to outline aspects of sport-related concussions most relevant in the management of young athletes seen in practice. At the outset, it is recognized that research-based data for the evaluation and management of sport-related concussions in children and adolescents are limited. Because no guideline or protocol has been specifically studied for its applicability in children and adolescents, a more cautious approach to management of concussions is recommended in this age group.

There is no universal consensus on the definition of concussion.1–4 In its practice parameter on concussion management in sports, the American Academy of Neurology defines concussion as a trauma-induced alteration in mental status that may or may not be associated with loss of consciousness.5 Confusion, loss of memory, and impaired information processing speed, which may occur immediately or several minutes later, are considered to be the key features of concussion and seen in all instances.1–8

The Prague Conference (Second International Conference on Concussion in Sports, 2004, Prague) in its definition includes the following key elements associated with concussion as a result of trauma in sports6:

1. 
   

   Concussion may be caused by a direct blow to the head, face, neck, or elsewhere on the body with “impulsive” force transmitted to the head.

   
   
2. 
   

   Concussion typically results in the rapid onset of short-lived impairment of neurologic function that resolves spontaneously.

   
   
3. 
   

   Concussion may result in neuropathologic changes, but the acute clinical symptoms largely reflect a functional disturbance rather than structural injury.

   
   
4. 
   

   Concussion may result in a graded set of clinical syndromes that may or may not involve loss of consciousness. Resolution of the clinical and cognitive symptoms typically follows a sequential course.

   
   
5. 
   

   Concussion is typically associated with grossly normal structural neuroimaging studies.

The term postconcussion syndrome refers to the persistence of symptoms and signs following the brain injury. Postconcussion syndrome can last for weeks, months, or years. Postconcussion syndrome indicates a more severe injury and precludes athlete’s return to high-risk sports.

In addition to direct impact to the head or other part of the body in contact/collision sports, concussion can also occur in noncontact sports as a result of sudden acceleration, deceleration, or rotational forces imparted to the brain.6–9 Thus, absence of a history of direct impact to the head or elsewhere on the body does not rule out the possibility of a concussion.

In high school sports in the United States, 300,000 head injuries are reported every year, and 90% of these are concussions.1–3 Reported incidence of concussions at high school level is 0.14 to 3.66 concussions per 100 player seasons accounting from 3% to 5% of all sport-related injuries.8 The highest number of concussion has been reported in American football (Table 11-1).1–4

Symptoms and signs of concussion are by definition transient and therefore many athletes may fail to grasp the significance of head trauma and subsequent symptoms of concussion and not seek timely medical attention. Some athletes may not report symptoms or head injury for fear of being excluded from further sport participation. Because of these reasons it is generally accepted that the reported incidence of concussion is an underestimate. Most athletes with concussion seen in a pediatric practice are adolescents, and the following discussion is most applicable to the adolescent age group.

Pathogenesis

Animal and experimental models have shown that in moderate to severe traumatic brain injuries a cascade of complex metabolic and biochemical changes in the setting of genetic overlay results in diffuse neuronal cell injury and dysfunction.2–9 Alterations in the intracellular and extracellular potassium and calcium ions and excitatory neurotransmitter glutamate have been described. It has been proposed that concussive brain injury causes a disturbance in the autoregulation of cerebral blood flow resulting in a relative decrease in cerebral blood flow, while at the same time there is an increased metabolic demand by the neuronal cells.2–9 The resultant mismatch between the cellular metabolic demands and cerebral blood flow is believed to be a key contributing factor leading to cellular dysfunction and increased vulnerability to further injury. There are fundamental differences between the developing brain of the child and adolescent and the mature brain of the adult making adult models of pathophysiology far less applicable to children. In broad terms, these differences include continuing neurocognitive maturation, anatomical configuration of the head and brain, structural properties of the skull, biomechanics of head trauma, vulnerability of neurons to injury, and neuronal recovery.2–9

History

Pediatricians may see an athlete with concussion on the field or more commonly in the office setting. On the sideline, the athlete may present with a history of direct blow to the head or other part of the body. The athlete may give a history of collision with another player, a fall to the ground, or being struck by an object such as a ball, a puck, or a bat. Concussion can result from indirect shearing or rotational forces imparted to the brain without direct impact. Not uncommonly, a teammate may notice that “something is not right” with the athlete and communicate that to the trainer on the sideline. The athletic trainer or the coach or less commonly a spectator may see collision and observe that the player is confused. Typically, the confused and disoriented athlete is not able to execute proper moves or follow commands as expected in the context of the play at the time.

The most common scenario for a pediatrician to see an athlete with a concussion is in the office setting when the athlete presents for a follow-up of head injury and needs a medical clearance to return to sport. The athlete may be symptomatic or asymptomatic. On the other hand, some athletes may initially present with symptoms or signs of concussion several days or weeks after the head injury; many may not realize the significance of the initial symptoms and delay seeking medical attention, or seek medical attention because of persistence or worsening or onset of new symptoms. Parents may first seek pediatrician’s advice when they notice deterioration of academic performance and changes in behavior, mood, or personality in the athlete; this is critically important to recognize and a probing history of antecedent head trauma must be ascertained.

During the annual sport preparticipation evaluation (PPE), a past history of head injury should be ascertained. Detailed history should include: when did the most recent concussion occurred, what were the symptoms and signs, how long did it take for full recovery, how many concussions have occurred in the past, interval between concussions, and results of any neuropsychologic testing or neuroimaging done.10–12 PPE visit is also the time for prevention education.

A relevant review of systems should include any known (preinjury) neurologic condition or learning disability, attention deficit hyperactivity disorder, depression, academic function before and since the injury, use of drugs or performance enhancing supplements, and use of therapeutic medications. Psychosocial history should assess athlete’s interest in sports, and any evidence of parental pressure to return to sport.13

Symptoms and Signs

The athlete with concussion may manifest any one or more of a number of symptoms or signs (Table 11-2); some immediately after the injury to the brain, whereas others may be delayed for days or weeks.3–8,14–17 Because no one or a set of symptoms and signs is pathognomonic of concussion, and most are nonspecific in nature, a contemporaneous relationship between the time of initial injury to the brain and subsequent development of symptoms and signs should be established on the basis of history and examination.

In the evaluation of an athlete with symptoms and signs of concussion the physician should consider other conditions that can present with similar clinical features. In the acute setting, heat-related illness, effects of dehydration, hypoglycemia, and acute exertional migraine can mimic concussion. Many of the delayed symptoms of concussion are nonspecific, making it necessary to carefully delineate the differential diagnosis or concomitant conditions such as depression, attention deficit/hyperactivity disorder, sleep disorder, cerebellar or brain stem lesions, or psychosomatic disorder. By definition a variable degree of mental status impairment is seen in all cases of concussion.

Mental Status and Cognitive Function

Assessment of cognitive functions and neurologic examination are essential components of evaluation of athletes with concussion. An athlete with concussion may continue to manifest physical and emotional symptoms even after resolution of cognitive deficits. Cognitive function can be affected by many factors other than the effects of concussion, such as baseline (preinjury) intellectual ability, learning disability, attention deficit/hyperactivity disorder, substance abuse, level of education, cultural background, lack of sleep, fatigue, anxiety, age, and developmental stage.1,2,18,19 Cognitive assessment techniques should be appropriate for the athlete’s age, level of education, and developmental stage or maturity.

A practical way to assess memory and orientation on the sidelines is Maddocks questions (Table 11-3); not able to answer or incorrect answer to any one of the Maddocks questions indicates concussion.20,21 The following areas of cognitive functioning and assessment techniques are generally included in a brief mental status examination of athletes with sport-related concussion.5–7,15,22,23

1. 
   

   Orientation—Orientation in person, place, and time.

   
   
2. 
   

   Attention

   
   
   
   
   • Digit span: Recite a series of two digits to the athlete at a rate of about one per second. Ask the athlete to repeat the numbers back to you. If the athlete is able to correctly repeat the two digits, recite a series of three numbers, then four, five, and so on, as long as the athlete is able to correctly repeat the digits back to you. If the athlete makes an error, try one more time with another series of the same length. Stop after the athlete fails at the second attempt. Similarly, have the athlete repeat the digits backwards starting with a series of two. Normally the athlete should be able to repeat correctly at least five digits forward and four backwards.
     
   • Serial 7s: Ask the athlete to subtract 7 from 100 and keep subtracting. Typically, the athlete should be able to complete a serial 7 in 1.5 minutes with fewer than four errors. If the athlete finds it difficult to do serial 7s, have him do serial 3s in a similar way.
     
   • Spelling backwards: Say a five-letter word, spell it, then ask the athlete to spell it backward.
   
   
   
   
3. 
   

   Memory

   
   
   
   
   • Give the athlete five words and ask him or her to repeat them back to you. The athlete with intact registration and immediate recall should be able to correctly repeat the five words back to you. Without informing the athlete that he or she will be asked to recall these words later, move on to another task of assessment in the meantime. Five minutes later ask the athlete to recall the five words. The athlete with intact delayed recall should be able to recall the five words.
     
   • Ask the athlete to recite the months of the year in reverse order starting with a given month or the current month (other than December or January).
     
   • Ask the athlete to tell current score of the game, which quarter it is and the name of the opposing team (recent memory).
     
   • Ask the athlete to tell you the name of his or her elementary school or place of birth (remote memory).
     
     
     
     • The onset of posttraumatic amnesia, a key feature of concussion, may be delayed for more than 20 minutes following injury to the brain.2 Resolution of posttraumatic amnesia is best indicated by the athlete’s ability to recall fully the events from before the injury to the brain to present (continuous memory).2,8,16
   
   
   
   
4. 
   

   Higher cognitive functions—General knowledge and vocabulary are good indicators of intellectual function. Assess calculation ability by asking the athlete to perform a simple task: how many nickels make a quarter? Or what is the square root of 64? Abstract thinking can be assessed by asking the athlete meaning of a common proverb for example: rolling stone gathers no moss; or by similarities test, for example: how are a train and an airplane similar? Constructional abilities give a good indication of visual motor abilities. To test constructional abilities ask the athlete to draw for example a clock face with numbers and hands and judge the quality of the drawing.

   
   
5. 
   

   Other areas of mental status—Insight, judgment, affect, and mood are other areas of mental status that should be assessed in athletes with concussion.

Neurologic Examination

A complete neurologic examination is essential in the evaluation of athletes with concussion with specific attention to the following components: (1) Speech, (2) visual acuity, visual fields, ocular fundi, pupillary reactions, and extraocular movements, (3) muscle strength and deep tendon reflexes, and (4) tandem gait, finger-nose test, pronator drift, and Romberg test. By definition, neurologic examination should be normal in athletes with concussion, except the mental status functions. Abnormal or focal findings on neurologic examination should prompt consideration of a focal intracranial pathology and emergent evaluation and management of the athlete.

Before the athlete is allowed to return to play, he or she must be asymptomatic both at rest as well as on exertion and the examination must be normal. The athlete should be assessed for recurrence of any symptoms or signs on physical exertion; simple exertion provocative measures (Table 11-4) can be integrated in the examination.2,5,6,8

Severity Grading of Concussions

Most concussion grading systems are based on the presence or absence of loss of consciousness, duration of loss of consciousness, presence or absence of confusion, and presence or absence and duration of posttraumatic amnesia, none of which have been shown to reliably predict the severity or prognosis for recovery.1–6,8,24 The duration of symptoms and signs following the initial brain injury has been shown to predict the severity of concussion and prognosis for recovery more reliably, hence the prevailing view is to consider the severity grading of concussion retrospectively after the clinical resolution of concussion.2,6,8,24 Although more than 20 grading schemes for concussion have been published, the American Academy of Neurology (Table 11-5) and Cantu (Table 11-6) grading systems are the most widely known.2,5,24