Postconcussion syndrome

Diagnosis

The DSM-5 definition (major or mild neurocognitive disorder due to traumatic brain injury) requires evidence of TBI plus one or more of the associated findings: loss of consciousness, posttraumatic amnesia, “disorientation and confusion”, or neurological signs such as new onset of seizures or worsening of pre-existing disorder, hemiparesis, anosmia, either clinically recognized or on imaging; signs must be evident immediately following the TBI and persist up to 3 months.

Symptoms following a concussion (often used synonymously with mild traumatic brain injury) can be categorized as early phase and late phase (Dwyer and Katz 2018).

• Early phase (days to weeks after injury): most common symptom is headache, can also include photophobia/phonophobia, dizziness, imbalance, fatigue, sleep disruption, cognitive symptoms (inattention, fogginess, word finding difficulties, memory problems, slowed processing), and emotional symptoms (irritability, anxiety) (Dwyer and Katz 2018)
  • Headache is typically tension or migraine-like. They can also be related to musculoskeletal injury (cervical whiplash, craniomandibular injury, occipital neuralgia from occipital nerve injury, trigeminal nerve injury) (Dwyer and Katz 2018)
  • Dizziness may represent vestibular or nonvestibular etiology, or may represent true vertigo in cases of benign paroxysmal positional vertigo (Dwyer and Katz 2018)
  • Most early-phase symptoms improve 2 weeks postinjury but in some cases take 4 weeks 74
• Late phase (months to years after injury): somatic, emotional, and cognitive symptoms (“persistent postconcussion syndrome” has no consensus as to the necessary duration of symptoms, and range between 3 months and a year) (Dwyer and Katz 2018)
  • Late phase symptoms are highly influenced by psychosocial factors and less specifically related to the brain injury itself. There is a substantial overlap between common symptoms of depression and symptoms attributed to the concussion (Dwyer and Katz 2018)
  • Only a minority of patients go on to develop late phase symptoms – risk factors include prominent early symptom burden (this is the strongest and most consistent predictor), premorbid psychiatric conditions, learning disorder, female gender, history of multiple concussions, younger age, and longer duration of unconsciousness or amnesia (Dwyer and Katz 2018)
  • At 1 year post-injury, a study of 421 mild TBI patients had no difference observed on any neuropsychological measure compared to trauma controls (with the exception of an isolated measure of episodic memory and learning in patients who had complicated mild TBI with positive head CT findings, though these are arguably not mild TBI); however, more than half continue to report symptoms 75
  • Assess for coexisting disorders (mood/anxiety disorders, poor sleep, chronic pain, vestibular dysfunction, MSK injury, psychosocial stressors, personality factors) (Dwyer and Katz 2018)

Treatment

• Early assessment, education about symptoms and expectations for recovery, minimize early-phase symptoms to prevent progression to late-phase disorder (i.e. treatment of depression, insomnia, headache, vertigo) (Dwyer and Katz 2018)
• For late phase treatment, in addition to identifying/treating the primary (i.e. treating cervical spine pathology or vestibular dysfunction) and secondary pathologies (i.e. treating depression with psychotherapy), there is early evidence to suggest efficacy of aerobic exercise to target deconditioning / autonomic instability (Dwyer and Katz 2018)

References

American Psychiatric Association. Diagnostic and statistical manual of mental disorders: DSM-5 (5th ed.). (American Psychiatric Association).

Dwyer, B. & Katz, D. I. Postconcussion syndrome. in Handbook of Clinical Neurology vol. 158 163–178 (Elsevier, 2018). https://pubmed.ncbi.nlm.nih.gov/30482344/