Description

• Postconcussion syndrome (PCS) is a constellation of symptoms involving physical, cognitive, and/or behavioral symptoms persisting after a concussion (mild traumatic brain injury [mTBI]) that may continue for weeks to years (1).
• It is unclear when concussive symptoms transition to become postconcussive syndrome. A recent consensus defines this as persistent symptoms lasting >10 to 14 days in adults and 4 weeks in children (2).
• Symptoms of PCS may include (1)
  • Cognitive
    • Poor focus
    • Poor organization
    • Diminished academic/intellectual performance
    • Slowed response time
  • Physical
    • Headache
    • Nausea
    • Visual changes
    • Light and noise sensitivity
    • Tinnitus
    • Dizziness and balance problems
    • Fatigue and sleep disturbance
  • Behavioral
    • Depression
    • Irritability/emotional lability
    • Apathy
    • Increased sensitivity to alcohol
• Diagnosis is based on history and clinical symptoms.

Epidemiology

Incidence
The reported frequency of patients with mTBI who develop PCS varies widely between 5% and 80%.

• Largely due to difficulty differentiating postconcussion symptoms from PCS
• 80–90% of concussion victims recover from postconcussion symptoms within 7 to 10 days, slightly longer in children/adolescents (2). A diagnosis of PCS is made in patients with persistent concussive symptoms.

Prevalence
Predominant sex: Females are slightly more likely to experience prolonged symptoms following a concussive injury.

Etiology and Pathophysiology

• Controversial; exact mechanism(s) unknown
• Microscopic axonal injury from shearing forces leads to inflammation causing secondary brain injury.
• Conflicting data on structural brain damage and correlation of imaging with physical symptoms (1)
• Because the pathophysiology of PCS is not well understood and because of symptom overlap with other psychiatric conditions, PCS remains difficult to diagnose and to manage.
  • Only some individuals with mTBI develop PCS; it is unclear what causes postconcussion symptoms to persist leading to postconcussion syndrome.
  • Behavioral factors are commonly associated with (and may play a role in) the development of PCS. It can be challenging to differentiate some behavioral disorders from PCS (1). Neuropsychiatry evaluation can be helpful.
  • Patients who reported high symptom burden following mTBI are at increased risk of PCS (3)[B].

Risk Factors

• Strongest predictor is severity of initial symptoms (2).
• Initial symptoms including retrograde amnesia, difficulty concentrating, disorientation, insomnia, loss of balance, sensitivity to noise, or visual disturbance (4)
• Preexisting psychiatric disease including depression, anxiety, personality disorder, and posttraumatic stress disorder (PTSD)
• Preexisting expectation of poor outcomes following mTBI (1)
• Nonsport concussion/mTBI
• Unclear if previous history of concussion(s) is a risk factor for PCS
• Low socioeconomic status
• Loss of consciousness is NOT predictive of PCS.

General Prevention

• Education of players, coaches, parents, and athletic trainers about concussion, PCS, and appropriate safety rules
• Head injury precautions are advised. Evidence is lacking that these decrease incidence of mTBI/PCS.
• Screening and intervention for anxiety and depression

Commonly Associated Conditions

• PTSD
• Anxiety
• Depression
• Fibromyalgia
• Personality disorders (namely, compulsive, histrionic, and narcissistic)
• ADHD