Lecture Notes: Concussion

What is a Concussion?

• A mild traumatic brain injury affecting normal brain functions.
• Caused by forceful blows to the head, either direct or indirect.
• Examples:
  • Direct blow: Injury on the side of impact or opposite side.
  • Indirect blow: E.g., whiplash causing brain to shake within the skull.
• Common causes include falls, contact sports, motor vehicle accidents, and physical abuse.

Mechanics of Brain Injury

• Types of Movement: Translational, Rotational, Angular
  • Rotational/Angular forces cause twisting of the brain against brainstem.
  • Brainstem injuries are serious as it controls vital functions, including consciousness.
• Concussion is a functional injury, not structural.
  • Brain appears normal on imaging tests.
  • Damage occurs microscopically, affecting large brain areas.
• Impact Dynamics:
  • Shockwaves stretch/shear neuron membranes, especially long axons.
  • Ionic imbalances and energy crisis due to reduced blood flow post-impact.
  • Ionic disturbances disrupt neuron communication.

Risks in Children and Teens

• Greater risk due to developing brain.
• Young brains have axons not fully myelinated, hence more susceptible to damage.
• Recovery in young people may take longer and brain development may pause.

Signs and Symptoms

• Subtle and may not appear immediately; can show up 20 minutes to hours after impact.
• Common symptoms:
  • Headache, drowsiness, dizziness
  • Sensitivity to light, memory loss
  • Difficulty concentrating, feeling slowed down
• Critical Observation:
  • Watch for 48 hours for worsening signs: loss of consciousness, severe headache, vomiting, speech issues, confusion, seizures, limb weakness.
  • Worsening symptoms require emergency care.

Recovery and Risks

• Concussion usually resolves with rest (physical and cognitive).
• Most recover in weeks, but some take longer.
• During recovery, avoid activities that risk further impact.
• Repeated injury during recovery increases risk of permanent damage or fatality.