What are the red flags for concussion?

Red Flags Requiring Emergency Referral

The following warrant immediate emergency department assessment, as they may indicate structural brain injury (e.g. intracranial bleeding) or cervical spine injury:

Consciousness and Cognition

• Prolonged loss of consciousness (≥2 minutes), or any deterioration in conscious state
• Inability to recognise people or places
• Increasing confusion, restlessness, agitation, or combativeness
• Excessive drowsiness or inability to be woken

Neurological

• Seizures or convulsions
• Pupillary asymmetry (one pupil larger than the other)
• Dysarthria (slurred speech)
• Weakness, tingling, or numbness in arms or legs
• Ongoing diplopia or other significant visual disturbances

Other Physical Signs

• Severe or worsening headache
• Repeated vomiting (>1 episode in adults; any vomiting in children)
• Severe neck pain or midline cervical tenderness
• Ongoing severe dizziness/vertigo
• Significantly unusual or inappropriate behaviour / personality changes

Higher-Risk Groups

The comparative significance of these red flags is heightened in:

• People aged ≥65 years (elevated risk of intracranial bleeding)
• Patients on anticoagulants or antiplatelets
• Prolonged post-traumatic amnesia (>12 hours)

Additional Notes

• Symptoms can appear or worsen in the first 24 to 48 hours after injury, so ongoing monitoring is essential
• Clinical decision rules (e.g. Canadian CT Head Rule) can help guide imaging decisions in the ED