Concussion

At the level of the neuron, linear and rotational forces can lead to structural and metabolic changes that transiently impair function and contribute to physical, cognitive, and emotional symptoms. The molecular substrate for these acute clinical changes is the subject of much current research on cellular ionic transients in sodium and calcium, axonal integrity, bioenergetics, neurovascular coupling, and genetics. What is apparent in sufferers of a concussion is that symptoms may persist for days, weeks, or months after a concussive event.

Clinical Symptomatology. The signs and symptoms of concussions are diverse. Typically, individuals have difficulty with thinking and memory skills, and their emotions may be affected. The physical problems include headache, nausea, and visual disturbances. The Centers for Disease Control and Prevention advocates that any athlete suspected of having a concussion should be immediately removed from play, evaluated by a health-care professional, and only allowed to return when cleared by a health-care professional. At present, there are no “neuroprotective” drugs that can be used for this condition, and it is recommended that for safety, physical and mental activities that excessively stimulate the injured brain should be discontinued. Furthermore, a graded return-to-play system is recommended as the safest way to bring an athlete back to full contact activities.

Second Impact Syndrome. Second impact syndrome is the most devastating, yet rare, consequence of repeat concussion in the postinjury phase. This condition occurs when an individual experiences a second traumatic episode to the brain before the brain has fully recovered from the initial traumatic injury. These subjects rapidly develop global cerebral edema, coma, severe neurologic impairment, and the potential for death. This rare condition has been observed mainly in youths younger than 21 years. At present, there are no methods for determining the recovery period after a concussion or even the duration of a “window of vulnerability” after a concussion. Hence much of the current emphasis in the management of concussion and return-to-playing of sports in young athletes is on reducing any potential for second impact syndrome.

Repeat Concussions and Chronic Traumatic Encephalopathy. Individuals who suffer an isolated concussive event should recover completely if they allow an appropriate time for recovery, with rest and cessation of sports. In contrast, brain autopsy studies of former professional athletes in contact sports, such as boxing, football, and hockey, have revealed a chronic, neurodegenerative disease termed chronic traumatic encephalopathy. This disease was first described in 1928 as dementia pugilistica in deceased boxers. The clinical syndrome associated with this pathology, so-called “punch drunk” condition, was believed to be limited to boxers who displayed progressive cognitive, emotional, and behavioral symptoms, such as depression, agitation, and dementia, years after repeated traumatic brain injuries. Recently, however, many other cases of chronic traumatic encephalopathy have been described in deceased players from other sports, for example, football, hockey, and wrestling. Although the cases vary in severity of neuropathology, they share the common feature of increased deposition of aggregated tau protein within neurofibrillary tangles, which is similar to neurodegenerative diseases such as Alzheimer disease. In addition, earlier stages of chronic traumatic encephalopathy are being reported in athletes as young as 18 years old, where there is evidence of white matter loss in brain imaging.

Only gold members can continue reading. Log In or Register to continue