Mild traumatic brain injury

Background

Mild TBI.JPG
  • Concussion (mild TBI)
    • GCS 14-15
    • Neurologic dysfunction that varies without gross lesions (ie patients have trouble with memory, attention, and executive functioning
    • Occurs after a blunt force or acceleration-deceleration head injury
    • Likely secondary to metabolic insult ie low oxygen state, ion changes
    • Structural imaging on MRI or CT might not indicate any injury
    • Often evidence on microscopic level of injury with histology
    • Important to not expose the already injured brain to repeated insults which is why there are usually worsening symptoms after a repeat concussion

Types

  • Simple concussion
    • Gradual resolution of symptoms within 7-10d
  • Complex concussion
    • Persisting symptoms or cognitive impairment
    • Symptoms with exertion

Pathophysiology

  • Predominantly metabolic insult
    • Mitochondrial dysfunction
    • shifts in calcium and sodium balances
  • Ultimately leads to damage to axonal integrity and axonal transport
  • Microscopic structural injury is often unidentifiable on CT or MRI

Clinical Features

  • Most consistent abnormality is subtle impairments in cognitive function
    • Attention, concentration, amnesia, memory, processing speed, reaction time, calculation, executive function
  • Physical signs/symptoms
  • Behavioral changes
    • Irritability, depression, anxiety, sleep disturbances, problems related to school/work, emotional lability, loss of initiative, loneliness and helplessness

Differential Diagnosis

Intracranial Hemorrhage Types

Evaluation

  • No reliable test that can confirm diagnosis of concussion
  • Clinical Signs and Symptoms may occur immediately or be delayed by days-weeks
  • Important to document full examination and should do gait and congnition testing
    • Mini Mental State Exam
    • Standardized Assessment for Concussion
      • Takes 10-15 mins to administer often not performed in ED

Management

Simple

  • Limitations on playing and training while symptomatic
  • Follow up with primary care provider

Complex

  • Refer to sports medicine or concussion specialist

Disposition

  • Given good follow up instructions detailing a graded return-to-activity program and symptoms to anticipate during recovery [1]
  • Discharge patient to care of responsible individual
  • Patients might not understand discharge instructions so repeat them to the individual taking care of the patient
  • Recommend strict rest for 1-2 days with gradual introduction back to regular activity[2]
  • Physical activity at any level (light aerobic, moderate, full) within first 7 days compared with no activity associated with lower rates of persistent symptoms at 28 days (29% vs. 40%)[3]
    • Multicohort study - 2400 children, aged 5-18, in the emergency department
    • Still recommend strict rest for first 24-48 hours

Prognosis

See also post-concussive syndrome

  • At 3 mo after injury 20-40% are symptomatic
    • with treatment for the most common symptoms of headache, difficulty concentrating and short-term memory difficulties being rest and in some circumstances NSAIDS.
  • At 1 yr after injury 15% are symptomatic

See Also

References

  1. Ronsford J, et al. Impact of early intervention on outcome after mild traumatic head in adults. 2002
  2. Thomas DG, Apps JN, Hoffmann RG, et al. Benefits of strict rest after acute concussion: a randomized controlled trial. Pediatrics. 2015; 2(135):213-223.
  3. Grool AM et al. Association Between Early Participation in Physical Activity Following Acute Concussion and Persistent Postconcussive Symptoms in Children and Adolescents. JAMA. 2016;316(23):2504-2514.