Health and Medicine

Diseases, Disorders, and Other Health Problems

What is a concussion?

A concussion is an injury to the brain caused by a blow or jolt to the head that disrupts the normal functioning of the brain. Concussions are usually not life-threatening. Since the brain is very complex, there is great variation in the signs and symptoms of a concussion. Some people lose consciousness; others never lose consciousness. Some symptoms may appear immediately, while others do not appear for several days or even weeks. Symptoms include:

  • Headaches or neck pain that will not go away
  • Difficulty with mental tasks such as remembering, concentrating, or making decisions
  • Slowness in thinking, speaking, acting, or reading
  • Getting lost or easily confused
  • Feeling tired all of the time, having no energy or motivation
  • Mood changes (feeling sad or angry for no reason)
  • Changes in sleep patterns (sleeping a lot more or having a hard time sleeping)
  • Light-headedness, dizziness, or loss of balance
  • Urge to vomit (nausea)
  • Increased sensitivity to lights, sounds, or distractions
  • Blurred vision or eyes that tire easily
  • Loss of sense of smell or taste
  • Ringing in the ears


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