A football coach asks: One of our defensive tackles sustained a concussion during a game last year. A doctor has seen him and told him it is OK to go back to sports. He is not complaining of any problems this year. When should I worry about a more severe concussion?

Dr. Patel writes: A concussion is when the brain sustains a traumatic event that is induced by outside forces such as a collision. It can also result from transmitted forces from another part of the body. Most of the times the symptoms are short lived impairments with a rapid onset and resolution.

A concussion results in a set of syndromes with or without loss of consciousness. Some other signs and symptoms of concussion are: Loss of consciousness, amnesia, disorientation, headaches, nausea / vomiting, drowsiness and slurred speech.

There are three grades to a concussion that may be useful for coaches / trainers to remember:

Grade 1 — No loss of consciousness or amnesia. Treatment involves return to play when the athlete is not complaining of any symptoms as long as he or she has not had more than three concussions in a season.

Grade 2 — Loss of consciousness for less than five minutes, confusion, or amnesia. These athletes should be taken out of the game for one week and return to play when they are not complaining of anything. Repeated episodes need to be evaluated by a doctor and suspension of play.

Grade 3 — Prolonged loss of consciousness, permanent amnesia and persistent disorientation to time, place, or person. These athletes should get an automatic suspension of play and needs to be seen by a healthcare professional immediately.