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Complications of Concussion

Concussion may cause a wide range of short- or long-term complications, affecting thinking, sensation, language or emotions. These changes may lead to problems with memory, communication, personality changes, as well as depression and the early onset of dementia. Below are other potential complications of concussion.

Post-concussion syndrome

  • Persistent post-concussion symptoms lasting three months or longer
  • Indicator of concussion severity
  • Precludes RTP while present
  • Increased risk of depression

Convulsive motor phenomena

  • Tonic posturing or convulsive movements within seconds of the concussion
  • Dramatic, but usually benign
  • Require no management beyond on-field ABCs
  • No anticonvulsant therapy required

Post-traumatic seizures

  • Seizure occurs days to months after concussion
  • Does require seizure management and precautions
  • Usually requires anticonvulsant therapy

Second-impact syndrome

  • Occurs within minutes of concussion in athlete still symptomatic from prior brain injury, which can be earlier in same event.
  • Vascular engorgement leads to massive increase in intracranial pressure and brain herniation resulting in severe brain damage or death.
  • May occur with associated small subdural hematoma.
  • Except for boxing, most cases in literature in adolescents.

Chronic Traumatic Encephalopathy (CTE)

  • A progressive neurodegenerative disease (tauopathy) caused by total brain trauma, and is not limited to athletes who have reported concussions.
  • The incidence and prevalence is unknown.
  • Diagnosed only after death by distinctive immunoreactive stains of the brain for Tau protein, and is not the same disease as Alzheimer’s.
  • Typical signs and symptoms include a decline of recent memory and executive function, mood and behavioral disturbances (especially depression, impulsivity, aggressiveness, anger, irritability, suicidal behavior and eventual progression to dementia).
  • Initial signs and symptoms do not typically manifest until decades after trauma received (ages 40-50).
  • Chronic Traumatic Encephalomyopathy (CTEM) A small subset of individuals with CTE develops a progressive motor neuron disease characterized by profound weakness, atrophy, spasticity and fasciculation similar to amyotrophic lateral sclerosis (ALS).

CTE

Source: Boston University Center for the Study of Traumatic Encephalopathy (CSTE)
Figure: Tau immunostained sections of medial temporal lobe from 3 individuals; Top left: Whole brain section from a 65 year old control subject showing no tau protein deposition; Bottom left: Microscopic section from 65 year old control subject also shows no tau protein;Top middle: Whole brain section from John Grimsley showing abundant tau protein deposition in the amygdala and adjacent temporal cortex; Bottom middle: Microscopic section showing numerous tau positive neurofibrillary tangles and neurites in the amygdala; Top right: Whole brain section from a 73 year old world champion boxer with severe dementia showing very severe tau protein deposition in the amygdala and thalamus; Bottom right:Microscopic section from a 73 year old world champion boxer with severe dementia showing extremely dense tau positive neurofibrillary tangles and neurites in the amygdala.

Depression

  • Increased risk following a history of multiple concussions
  • May pre-date concussion and/or occur independent of concussion
  • Athletes with depression who later sustain concussion may experience worsening symptoms.


Mild-Cognitive Impairment

  • Increased risk later in life following a history of multiple concussions.
  • May pre-date concussion and/or occur independent of concussion
  • Multiple concussions have been associated with an earlier onset of mild cognitive impairment

Adapted from: Herring et al. Concussion (Mild Traumatic Brain Injury) and the Team Physician: A Consensus Statement. Medicine and Science in Sports & Exercise. in press.

 

 

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