Concussion
Concussion (mild traumatic brain injury) is a biomechanically induced, temporary alteration of brain function with a normal neurologic examination and, when obtained, a normal head CT. Management is symptom-guided with an early, graduated return to activity; most symptoms resolve within 7 to 10 days.
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What this article covers
- Overview
Definition: concussion, synonymous with mild traumatic brain injury (mild TBI), is a clinical syndrome of biomechanically induced, temporary alteration of brain function following a direct or…
- Epidemiology
Common mechanism spectrum: falls, motor vehicle collisions, assaults, and sports participation are the leading causes; after accidents generally, sporting activities are the second most common source…
- Risk factors
Prior concussion: a history of previous concussion increases risk of another concussion and of a more prolonged postconcussive course.
- Pathophysiology
Biomechanical force transmission: rotational and linear acceleration-deceleration forces applied to the head and neck cause a transient neurometabolic cascade and disruption of neuronal and axonal…
- Clinical features
Four symptom domains: physical (headache, nausea/vomiting, dizziness/vertigo, gait disturbance, photophobia/phonophobia, visual blurring, dysarthria, seizures), cognitive (poor concentration, mental…
- Differential diagnosis
Moderate or severe traumatic brain injury: GCS 12 or less, loss of consciousness beyond brief duration, or structural findings (contusion, hemorrhage, edema, skull fracture) on head CT are absent in…
- Diagnosis
Clinical diagnosis: concussion is diagnosed clinically based on a biomechanically plausible mechanism, characteristic transient alteration of brain function, and (when obtained) a normal head CT; no…
- Management
First step, acute injury: immediate removal from play or the precipitating activity and structured sideline assessment; if any CDC head CT criterion is met, obtain noncontrast head CT before further management decisions.
- Complications
Postconcussive syndrome: persistent physical, cognitive, psychological, and sleep symptoms extending beyond the typical 7-to-10-day resolution window, requiring multidisciplinary management.
- Prognosis
Favorable in most patients: the large majority of concussions resolve spontaneously within 7 to 10 days with no long-term sequelae.
- Prevention
Immediate removal from play: any athlete suspected of sustaining a concussion should be removed from play immediately and assessed by a provider trained in concussion evaluation, preventing a second…
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Related articles
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- Migraine headache
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- Tension-type headache
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- Chronic subdural hematoma
A collection of liquefied blood between the dura and arachnoid that develops over weeks after often-trivial or forgotten trauma, typically in elderly or anticoagulated patients with cerebral atrophy; CT confirms the diagnosis, and burr-hole drainage is the treatment for a symptomatic hematoma with significant thickness or midline shift.
- Epidural hematoma
Epidural hematoma is an arterial bleed, classically from the middle meningeal artery after a temporal bone fracture, that collects between the skull and dura in a biconvex shape that does not cross suture lines; a lucid interval followed by rapid decline is classic, and a GCS below 9, anisocoria, or hematoma over 30 mL requires urgent surgical evacuation.
- Acute subdural hematoma
Acute subdural hematoma is venous bleeding between the dura and arachnoid membrane from ruptured bridging veins, producing a crescent-shaped collection that crosses suture lines on CT. Older adults and patients with alcohol use disorder or on anticoagulation are most susceptible; a hematoma over 10 mm, a GCS under 9, or pupillary asymmetry mandate immediate surgical evacuation.