Like broken bones, brain trauma needs time to heal

Q. My 12-year-old son is an avid BMX racer. At a race this weekend he crashed and was knocked out for a few seconds. The ER doctor said he had a concussion, and watched him for a few hours. Since then he's felt fine and is keen to race again. When can he?
- SF
A. A concussion is when you get hit in the head, and your brain stops working normally. This could mean seeing stars, feeling dazed, or losing consciousness. It is the mildest form of a traumatic brain injury.
In the event of a trauma, the scalp, skull, and cerebrospinal fluid absorb some energy, with the rest transmitted to the brain, an organ with the firmness of soft cheese.
Too-sudden an impact, and the brain deforms against the skull. It rebounds, and although the CT scan of the brain will look normal, at a cellular level there is damage. The result of this damage in the short term can be a loss of consciousness, confusion, or amnesia. Over the longer term one can have headaches, trouble concentrating, or irritability which lasts from days to months, and in a unlucky few, persists indefinitely. Specialists debate when it's safe to return to sport, with multiple guidelines based more on expert opinion than on controlled trials. For a few seconds of lost consciousness, most guidelines suggest no return to play for one week after all symptoms have resolved.
A return of symptoms (such as headache) would mean an immediate stop and follow up with an experienced physician for re-evaluation. One concern is second-impact syndrome, a rare and poorly understood condition where a person still recovering from a first concussion sustains a second minor concussion, but with unexpectedly devastating outcomes.
There are also long-term issues of the link between repeated concussions and memory loss, depression, and even Parkinson's disease.
The take home points for readers are that concussions are brain injuries, and injuries need time to heal.
Gary Payinda MD is an emergency medicine consultant in Whangarei.
Have a science, health topic or question you'd like addressed? Email: drpayinda@gmail.com
(This column provides general information and is not a substitute for the medical advice of your personal doctor.)