Mild Traumatic Brain Injury — Concussion in Adults

Key Points

• Concussion is a clinical diagnosis and conventional CT is usually normal.
• Use validated CT decision rules only in the populations for which they were designed.
• Anticoagulated patients often warrant initial CT even when other features appear low risk.
• A neurologically baseline anticoagulated patient with a negative CT does not routinely need repeat CT or mandatory admission solely because of anticoagulation.
• Recommend 24 to 48 hours of relative rest followed by gradual return to activity.
• Prolonged strict rest can delay recovery and is not recommended.
• Avoid repeat head injury until symptoms have resolved and return-to-activity criteria are met.
• Clear written return precautions are essential because deterioration can occur after discharge.

Algorithm

1. Assess GCS, neurologic examination, mechanism, vomiting, headache, amnesia, skull-fracture signs, intoxication, and anticoagulant use.
2. Apply an appropriate validated head CT rule when the patient meets its inclusion criteria.
3. Obtain noncontrast head CT when indicated or when clinical red flags override a low-risk pathway.
4. If CT shows intracranial injury, manage according to trauma and neurosurgical protocols.
5. If CT is negative and neurologic status is baseline, treat symptoms and determine whether any non-head-injury reason for observation exists.
6. Provide written danger signs and concussion-specific recovery instructions.
7. Recommend 24 to 48 hours of relative rest, then gradual sub-symptom activity.
8. Arrange follow-up for persistent symptoms or higher risk of prolonged recovery.

Clinical Synopsis & Reasoning

Concussion can follow a direct blow to the head, face, or neck or a force transmitted to the brain from an impact elsewhere on the body. Loss of consciousness is not required. Symptoms can include headache, dizziness, nausea, light or noise sensitivity, slowed thinking, poor concentration, memory difficulty, imbalance, irritability, anxiety, fatigue, and sleep disturbance. The diagnosis is clinical because conventional CT and MRI are usually normal in uncomplicated concussion.

The ED task is to separate concussion from structural traumatic brain injury. Assess Glasgow Coma Scale, repeated vomiting, severe or worsening headache, seizure, focal neurologic deficit, signs of skull fracture, dangerous mechanism, intoxication, anticoagulant or antiplatelet use, age, amnesia, and persistent altered mental status. Validated head CT decision rules, particularly the Canadian CT Head Rule in the population for which it was developed, reduce unnecessary imaging. Decision rules should not be applied outside their validated inclusion criteria or used to override major clinical red flags.

Patients taking anticoagulants or antiplatelet agents other than aspirin alone deserve a low threshold for initial CT because decision rules may not safely exclude hemorrhage in this group. Current ACEP guidance supports discharge after a single negative CT in many anticoagulated patients who have returned to baseline neurologic function, without routine repeat CT or mandatory observation solely because of the medication, provided there are no other reasons for monitoring and reliable discharge instructions can be given.

Concussion symptoms may evolve after discharge, so patient education is part of diagnosis. A normal CT excludes many dangerous acute structural injuries but does not rule out concussion. Conversely, persistent neurologic decline, repeated vomiting, worsening headache, focal weakness, seizure, or increasing confusion should not be attributed to a benign postconcussive course without reassessment.

Treatment Strategy & Disposition

Treat pain and nausea symptomatically while avoiding unnecessary sedation that obscures neurologic assessment. Acetaminophen is commonly used early. NSAIDs can be used in selected patients after clinically important intracranial bleeding has been excluded and bleeding risk is acceptable. Routine corticosteroids, prophylactic antiseizure medication, and strict prolonged bed rest are not treatments for uncomplicated concussion.

Recommend 24 to 48 hours of relative physical and cognitive rest rather than complete sensory deprivation. Patients do not need to remain in a dark room without activity. After the brief rest period, begin light daily activity and low-level aerobic exercise that does not substantially worsen symptoms. Increase activity gradually. Mild transient symptom increase during recovery can occur, but significant or sustained worsening should lead to a reduction in activity and reassessment.

Patients should avoid activities with meaningful risk of another head impact until recovered and cleared when appropriate. Return to driving, work at heights, heavy machinery, and other safety-sensitive tasks depends on symptoms such as slowed reaction time, dizziness, visual disturbance, and concentration difficulty. Athletes should follow a staged return-to-play protocol and should never return to contact sport on the same day as a suspected concussion.

Discharge is appropriate when the patient is neurologically stable, serious intracranial injury has been reasonably excluded, symptoms are controlled, and reliable observation and return precautions are available. Arrange follow-up for patients at increased risk of prolonged symptoms, including those with prior concussions, significant initial symptom burden, migraine, mood disorders, vestibular symptoms, or occupational and academic consequences. Persistent symptoms benefit from targeted rehabilitation such as vestibular, cervical, headache, sleep, or neuropsychological care rather than indefinite rest.

Epidemiology / Risk Factors

• Concussion accounts for a large proportion of mild traumatic brain injury visits.
• Falls, motor vehicle crashes, occupational injuries, assaults, and sports are common mechanisms.
• Most adults improve substantially within days to a few weeks.
• Prior concussion, migraine, mood disorders, and high early symptom burden can prolong recovery.
• Repeat injury before recovery can worsen symptoms and increases risk of another concussion.

Investigations

When to Image

Pharmacology

Prognosis / Complications

• Most adults recover without permanent neurologic disability.
• Symptoms often improve over one to two weeks, although a meaningful minority have longer courses.
• Persistent symptoms can affect work, school, sleep, mood, and driving even when structural imaging is normal.
• Targeted rehabilitation and gradual activity are more useful than prolonged inactivity for many persistent symptoms.
• New neurologic deterioration after an initially reassuring visit requires urgent reassessment for delayed or previously occult injury.

Patient Education / Counseling

• Provide written red flags: worsening severe headache, repeated vomiting, increasing confusion, seizure, weakness, slurred speech, unusual behavior, inability to awaken, or new vision or balance problems.
• Use relative rest for the first 24 to 48 hours, then gradually resume normal activities below the threshold that causes marked symptom worsening.
• Avoid alcohol, recreational drugs, and activities with another head-impact risk during recovery.
• Do not return to contact sports on the day of injury.
• Delay driving or safety-sensitive work while dizziness, slowed thinking, visual disturbance, or poor concentration is present.
• Arrange follow-up if symptoms persist beyond the expected course or interfere substantially with daily function.

Notes

Concussion management has shifted away from prolonged strict rest. A short period of relative rest helps during the most symptomatic phase, but recovery generally benefits from gradual resumption of activity. The patient should use symptoms as a guide rather than trying to eliminate every sensation before moving at all.

The other major shift is more selective use of repeat imaging and observation. A patient on anticoagulation still deserves careful initial assessment, but a stable baseline neurologic examination and negative CT can support discharge when no other risk factor requires admission. Reliable instructions and return access are essential parts of that decision.

References

1. ACEP Clinical Policy: Mild Traumatic Brain Injury — Link
2. CDC Mild TBI Management Resources — Link