Neurology · Traumatic Brain Injury
The facts most likely to be tested
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A concussion is a functional rather than structural injury, meaning non-contrast head CT will be normal in the absence of intracranial hemorrhage.
The Canadian CT Head Rule mandates imaging for patients with GCS < 15 two hours post-injury, suspected open or depressed skull fracture, or signs of basilar skull fracture.
Loss of consciousness is not required for the diagnosis of a concussion, as most patients remain conscious throughout the event.
Relative (not strict) physical and cognitive rest is the initial management strategy for the first 24–48 hours, followed by a graduated return-to-activity protocol.
Second-impact syndrome is a rare, potentially fatal condition caused by a second concussion occurring before the symptoms of the first have fully resolved, leading to cerebral edema.
Persisting symptoms after concussion (formerly post-concussion syndrome) is defined by the persistence of symptoms such as headache, dizziness, and cognitive impairment beyond the expected recovery window (commonly >4 weeks).
Return-to-play decisions in athletes must follow a stepwise progression where each stage lasts at least 24 hours; brief, mild symptom exacerbation (<=2 points on a 0-10 scale, resolving within 1 hour) is permitted during the early non-contact steps.
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A 17-year-old high school football player is evaluated on the sideline after a helmet-to-helmet collision. He reports a transient headache and dizziness but denies loss of consciousness. On examination, he is alert and oriented, follows commands, and has a GCS of 15. His neurological exam is non-focal, and he has no signs of trauma to the head or neck. He is currently asymptomatic at rest.
What is the most appropriate next step in management?
Removal from play and initiation of a graduated return-to-activity protocol.
The patient meets the criteria for a concussion but does not meet the Canadian CT Head Rule criteria for imaging; therefore, the focus is on relative (not strict) physical and cognitive rest for 24-48 hours, followed by early symptom-limited activity and a graduated return-to-sport strategy.
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Etiology / Epidemiology
Traumatic brain injury caused by biomechanical forces; common in contact sports and falls.
Clinical Manifestations
Transient altered mental status and post-traumatic amnesia; symptoms often delayed.
Diagnosis
Clinical diagnosis; CT head only if red flags present per Canadian CT Head Rule.
Treatment
Relative rest for 24-48 hours, then symptom-limited activity; no return to play until the graduated return-to-sport strategy is completed with medical clearance.
Prognosis
Most resolve within 2 weeks in adults and 4 weeks in children/adolescents; risk of second impact syndrome if premature return.
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Epidemiology & Etiology
Concussions result from direct blows or impulsive forces transmitted to the head. Contact sports (football, hockey) and falls are the leading causes in pediatric and geriatric populations. Recurrent injury significantly increases the risk of long-term neurocognitive deficits.
Pertinent Anatomy
The brain undergoes rotational acceleration within the cranium, causing shearing of axons. The corpus callosum and brainstem are particularly vulnerable to these diffuse forces.
Pathophysiology
Injury triggers a metabolic crisis characterized by an efflux of potassium and influx of calcium. This leads to a state of hypermetabolism followed by a period of reduced cerebral blood flow. The resulting energy crisis renders the brain highly susceptible to secondary injury.
Clinical Manifestations
Patients present with confusion, headache, dizziness, and nausea. Red flags requiring urgent imaging include focal neurologic deficits, worsening headache, or repeated vomiting. Post-traumatic amnesia and loss of consciousness are common but not required for diagnosis.
Diagnosis
Diagnosis is strictly clinical; CT head is reserved for patients meeting Canadian CT Head Rule criteria (e.g., age >=65, GCS <15 at 2 hours, or suspected open skull fracture). Neuropsychological testing (e.g., ImPACT) may assist in tracking recovery but is not diagnostic.
Treatment
Initial management requires relative physical and cognitive rest for 24-48 hours; strict rest until symptoms resolve is not recommended. Acetaminophen is preferred initially; NSAID use is individualized given theoretical bleeding concerns. Early sub-symptom-threshold aerobic activity (e.g., walking) may begin within 24-48 hours, and gradual, symptom-limited return to activity is the first-line approach; no return to play on the same day as injury.
Prognosis
Most patients recover within 4 weeks (typically ~2 weeks in adults, up to 4 weeks in children and adolescents); 20-30% have persisting symptoms. Failure to adhere to rest protocols risks second impact syndrome, a rare but fatal condition involving rapid cerebral edema.
Differential Diagnosis
Intracranial hemorrhage: focal neurologic deficits and rapid decline
Skull fracture: palpable bony step-off or Battle sign
Cervical spine injury: neck pain and radiculopathy
Persisting symptoms after concussion: symptoms lasting >4 weeks at any age
Migraine: unilateral throbbing headache with aura