Second impact can lead to severe swelling of the brain and death

Dr. Wendy Lin

Every year there are more than 300,000 emergency department visits for concussions in the United States. A concussion is a clinical syndrome characterized by short-term changes in brain function resulting from a physical impact. This can include hits directly to the head or neck or anywhere in the body causing forces transmitted to the brain.

The main symptoms include, but are not limited to, headache, nausea and mood changes. Concussions do not require loss of consciousness. These symptoms are due to changes in metabolism in the brain rather than a structural injury. Research has shown that after a concussion, there is decreased blood flow to the brain and changes in the concentrations of chemicals in the brain. These changes usually return to normal in about two weeks coinciding with recovery of symptoms. When symptoms last longer, more testing may be required.

Second impact syndrome and chronic traumatic encephalopathy are the more frightening things reported as a result of repeated concussions. Second impact syndrome is an extremely rare entity described as severe swelling of the brain leading ultimately to death. It has been reported mainly in high school male athletes. It can occur after a relatively light impact, before the brain has fully healed from an initial concussion. Chronic traumatic encephalopathy has been described as a degenerative disease of the brain caused by repeat concussions in adult athletes. Symptoms include memory loss, and mood and behavior changes. The brains of former athletes who have had repeated concussions with these symptoms look like brains of patients with Alzheimer’s disease.

“When can I return to the game?” is the question that all athletes have after any injury. According to California Assembly Bill 25 signed on Oct. 4, 2011, the student-athlete who is suspected of sustaining a concussion or head injury during practice or a game is removed for the remainder of the day. The athlete “... shall not be permitted to return to the activity until he or she is evaluated by a licensed health care provider, trained in the management of concussions...”

Neurologic recovery is often just a waiting game with symptoms improving over time. Neuropsychologists often work with physicians to help evaluate when there is full cognitive recovery. Afterward, there is a step by step approach to return to full play that takes at least one week to complete.

Protective equipment is only one part of concussion prevention. There are always new products coming out for various sports. No matter what equipment the athlete wears it is important that the equipment fits well and he/she is strong enough to use it.

Equipment is not the only thing to rely on, however. Physical conditioning and good decision making are also key to concussion prevention. Good endurance, core and neck strength, balance and agility are what the body needs to reduce the impact to the brain.

Dr. Wendy Lin is a pediatric rehabilitation medicine specialist at Rady Children’s Hospital San Diego. She can be reached at