What are the signs and symptoms that indicate a concussion requires emergency room (ER) referral, particularly in patients with a history of prior concussions, anticoagulant medication (e.g. warfarin (coumarin) or aspirin (acetylsalicylic acid)) use, bleeding disorders, or underlying medical conditions such as dementia?

Signs and Symptoms of Concussion Requiring Emergency Room Referral

Activate emergency medical services immediately for any patient with concussion who develops loss of consciousness, worsening headache, repeated vomiting, altered mental status, seizures, visual changes, or visible scalp swelling/deformities. 1

Critical Red Flags Mandating Immediate ER Evaluation

The following signs and symptoms indicate severe head injury with increased risk of life-threatening complications such as epidural hematoma, subdural hematoma, skull fracture, or brain edema requiring hospital treatment: 1

Neurological Deterioration

• Loss of consciousness (occurs in <10% of concussions but represents a critical warning sign) 1, 2
• Altered mental status including confusion, disorientation, or decreased responsiveness 1
• Seizure activity or convulsions 1
• Focal neurologic deficits such as weakness, numbness, or abnormal reflexes 1, 3

Progressive Symptoms

• Worsening headache that progressively intensifies rather than improves 1
• Repeated vomiting (not just single episode of nausea) 1
• Increasing sleepiness or difficulty staying awake 1

Visual and Cognitive Changes

• Visual changes including blurred vision, double vision, or visual field defects 1
• Problems remembering or severe confusion 1, 3
• Abnormal behavior or personality changes 1

Physical Examination Findings

• Visible swelling or deformities of the scalp suggesting skull fracture 1
• Signs of skull fracture on examination 1

High-Risk Populations Requiring Lower Threshold for ER Referral

Anticoagulated Patients

Patients taking anticoagulants (warfarin, novel oral anticoagulants) or antiplatelet agents (aspirin, clopidogrel) face 2-6 times greater mortality risk from traumatic intracranial hemorrhage and require heightened vigilance for delayed bleeding. 4 These patients warrant emergency evaluation even with milder symptoms due to increased risk of epidural hematoma, subdural hematoma, and progressive intracranial bleeding. 4

Key consideration: Warfarin use with INR ≥2.0 is associated with increased severity of traumatic brain injury and higher likelihood of intracranial hemorrhage requiring neurosurgical intervention. 4

Patients with Dementia

Patients with pre-existing dementia require special attention as they have higher baseline risk of adverse outcomes and may not reliably report symptoms. 5 Any head trauma in this population warrants careful monitoring and lower threshold for imaging and emergency evaluation. 5

History of Multiple Prior Concussions

Patients with history of multiple concussions are at higher risk for prolonged recovery and should be evaluated more conservatively. 6 The concept of postconcussive vulnerability suggests that a second injury before complete recovery results in worsening metabolic changes and prolonged dysfunction. 6

Initial Assessment and Monitoring

Any patient with suspected concussion must be immediately removed from activity and monitored for deterioration. 1 Home observation should focus on watching for the red flag symptoms listed above rather than frequent waking or pupil checks, which are not supported by evidence. 1

Return Instructions for Patients and Caregivers

Patients discharged from initial evaluation must return immediately to the emergency department if they develop: 1, 3

• Repeated vomiting
• Worsening headache
• Problems remembering
• Confusion
• Focal neurologic deficit
• Abnormal behavior
• Increased sleepiness or passing out
• Seizures

Common Pitfalls to Avoid

Do not rely on loss of consciousness as a requirement for serious injury - LOC occurs in less than 10% of concussions, yet patients without LOC can still develop life-threatening intracranial hemorrhage. 1, 2

Do not dismiss symptoms in anticoagulated patients - even with normal initial presentation, these patients require CT imaging and extended observation due to risk of delayed intracranial bleeding. 4

Do not assume symptom resolution means safety - symptoms may evolve over minutes to hours following injury, requiring continued monitoring. 1, 2

Recognize that standard orientation questions (time, place, person) are unreliable - memory assessment is more sensitive for detecting concussion than basic orientation. 1