Traumatic Brain Injury (TBI) is an intracranial injury that occurs when an external force injures the brain. When clinically significant, the DSM-5 diagnoses are major neurocognitive disorder or mild neurocognitive disorder due to Traumatic Brain Injury.[1]
The criteria are met for major or mild neurocognitive disorder
There is evidence of a traumatic brain injury—that is, an impact to the head or other mechanisms of rapid movement or displacement of the brain within the skull, with one or more of the following:
The neurocognitive disorder presents immediately after the occurrence of the traumatic brain injury or immediately after recovery of consciousness and persists past the acute post-injury period.
Concussions can be considered a form of mild traumatic brain injury. A regional study of Canadian adolescents found that approximately 20% of all adolescents have sustained a concussion[11]
Chronic traumatic encephalopathy (CTE) is a term used to describe brain degeneration likely caused by repeated head trauma. CTE is thought to significantly increase the risk for dementia.[12] A diagnosis of CTE can only be made during autopsy. CTE is a rare condition and usually found in individuals who play contact sports.
The cognitive presentation and symptoms after a TBI can be variable. Difficulties in the domains of complex attention, executive ability, learning, and memory are common as well as slowing in speed of information processing and disturbances in social cognition. In more severe TBIs that involve brain contusion, hemorrhage, or a penetrating injury, there can be more neurocognitive deficits, such as aphasia, neglect, and constructional dyspraxia. TBIs are also associated with:
Injury characteristic | Mild TBI | Moderate TBI | Severe TBI |
---|---|---|---|
Loss of consciousness | <30 minutes | 30 minutes-24 hours | >24 hours |
Posttraumatic amnesia | <24 hours | 24 hours-7 days | 7 days |
Glasgow Coma Scale on assessment | 13-15 (not below 13 at 30 minutes) | 9-12 | 3-8 |
Depending on the neuroanatomical region of the injury, symptoms of TBI can vary as described above. In general, TBIs can cause a variety of cytotoxic processes, including axonal injury, free-radical injuries, changes in Mg+2 and Ca+2 signalling, and neurotransmitter excitotoxicity. These changes contribute to a range of cognitive and neuropsychiatric symptoms.
In some instances, the severity of neurocognitive symptoms may appear to be inconsistent with the severity of the TBI. After previously undetected neurological complications (e.g., chronic hematoma) are excluded, the possibility of diagnoses such as somatic symptom disorder or factitious disorder need to be considered. Posttraumatic stress disorder can co-occur with the neurocognitive impairment and have overlapping symptoms (e.g. - difficulty concentrating, depressed mood, aggressive behavioural disinhibition).
Biomarkers for acute concussion have been identified, including ubiquitin carboxy-terminal hydrolase L1 (UCH-L1).[14] The FDA has recently approved this for clinical use.
There are no approved pharmacological treatments for TBI, and use is off-label to address neuropsychiatric symptoms related to the injury.[15] A variety of medications can be used depending on the symptom.
If there is no urgent or acute symptoms, do watchful waiting and assess for spontaneous resolution of symptoms first. A “start low and go slow” approach is important as those with TBI have increased sensitivity to to cognitive side effects of psychotropic and neurological medications.
Dopamine agonists | Amantadine 100 to 300mg daily, bromocriptine 5 to 45mg daily |
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Acetylcholinesterase inhibitors | Donepezil, rivastigmine 3 to 6mg daily[16] |
Stimulants | Methylphenidate 10 to 15mg BID, modafinil 100 to 400mg daily |
SSRIs | Fluoxetine 60mg daily, sertraline 100mg daily |
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Anticonvulsants | Valproic acid 600 to 2250mg daily, carbamazepine 400 to 800mg daily |
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Beta-blockers | Propranolol up to 420mg/daily,[17] pindolol 60 to 100mg daily |
Mood stabilizers | Lithium 900mg daily |
Second generation antipsychotics | Clozapine 300 to 500mg daily, quetiapine 25 to 300mg daily, ziprasidone 20 to 80mg daily |
Stimulants | Methylphenidate 10 to 15mg BID, modafinil 100 to 400mg daily |
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Guideline | Location | Year | Website | |
---|---|---|---|---|
Evidence-Based Review of Moderate-to-Severe Brain Injury (ERABI) | Canada | 2007 | Link | Link |
Ontario Neurotrauma Foundation | Canada | 2017 | Link | Link |
British Columbia Medical Journal (BCMJ) | Canada | 2010 | - | Link |
BMJ Open (Systematic Review) | UK | 2019 | - | Link |
PsychiatricTimes (Expert Opinion) | USA | 2019 | - | Link |
Tele-Rehabilitation Interventions through University-based Medicine for Prevention and Health (TRIUMPH) | USA | 2020 | Link | - |