What are the stages of concussion and how to identify a patient with concussion?

Identifying a Patient with Concussion

Any patient with a head injury and any alteration in consciousness or the typical constellation of concussion symptoms across physical, cognitive, emotional, or sleep domains should be immediately suspected of having a concussion and removed from activity for formal medical evaluation. 1, 2

Clinical Diagnosis Framework

Concussion is a clinical diagnosis based on the temporal relationship between a mechanism of injury (direct blow to head, face, neck, or impulsive force transmitted to the head) and the subsequent development of characteristic symptoms. 1, 3 There are no "stages" of concussion per se—rather, concussion presents with an evolving constellation of symptoms that are typically most severe in the first 24-48 hours and follow a sequential resolution pattern. 4, 5

Recognition: The Four Symptom Domains

Physical Symptoms

• Headache (most common, occurring in the majority of cases) 2
• Dizziness and balance problems 2, 6
• Nausea and vomiting 2, 6
• Visual disturbances (blurred vision, double vision, photophobia) 2, 6
• Noise sensitivity (phonophobia) 2
• Fatigue and drowsiness 2, 6
• Numbness 2

Cognitive Symptoms

• Difficulty concentrating and remembering 2, 6
• Mental fogginess or feeling "slow" (predicts slower recovery) 2
• Confusion 2, 6
• Amnesia (both retrograde and anterograde—critical indicator of more serious injury) 2, 6
• Slowed reaction time 6

Emotional/Behavioral Symptoms

• Irritability 2, 6
• Anxiety 2, 6
• Sadness or depression 2
• Feeling more emotional 2
• Mood disturbances 6

Sleep Disturbances

• Trouble falling asleep 2
• Excessive sleep 2
• Loss of sleep 2
• Drowsiness 2, 6

Critical Red Flags Requiring Emergency Evaluation

Immediately activate emergency medical services if any of these are present: 6, 7

• Loss of consciousness (though this occurs in <10% of concussions) 2, 6, 7
• Worsening or severe headache 6, 7
• Repeated vomiting 6, 7
• Altered mental status or deteriorating neurological status 6, 7
• Seizure activity 6, 7
• Visual changes 6, 7
• Signs of skull fracture (Battle's sign, raccoon eyes, hemotympanum, CSF leak) 6, 7

Temporal Pattern of Symptom Onset

Symptoms may present immediately OR be delayed in onset. 2, 8 Approximately 16.7% of pediatric patients experience delayed symptom onset (≥15 minutes from injury, with median onset at 60 minutes). 8 This delayed presentation does NOT indicate a less severe injury—patients with delayed symptom onset have similar symptom severity, recovery length, and rates of delayed recovery compared to those with immediate symptoms. 8

Practical Assessment Approach

In the absence of a validated single-stage concussion scoring system, assessment should be based on the typical signs and symptoms of concussion. 1 The 2022 International Consensus emphasizes this good practice statement because no evidence supports specific scoring systems for first aid providers. 1

Immediate Sideline/Field Assessment

• Remove from activity immediately if ANY single symptom or sign is present 6, 7
• Document mechanism of injury 3
• Assess for red flags requiring emergency transport 6, 7
• Evaluate cervical spine 6
• Use graded symptom checklist (0-6 severity scale across all domains) 2, 3
• Test memory (retrograde and anterograde amnesia) 6, 3
• Perform balance testing 3
• Conduct brief neurological examination 3
• Serial monitoring every 5 minutes until condition improves 6

Key Diagnostic Considerations

Loss of consciousness is NOT required for diagnosis—it occurs in less than 10% of concussions and its absence does not rule out concussion. 6, 7, 3 The majority of concussions occur without loss of consciousness or frank neurological signs. 4

Symptoms cannot be explained by drug, alcohol, medication use, cervical injuries, peripheral vestibular dysfunction, or other comorbidities—careful differential diagnosis is essential. 1, 2

Standard neuroimaging (CT, MRI) is normal in concussion because symptoms reflect functional disturbance rather than structural injury. 1, 5 Imaging is reserved only for suspected intracranial bleeding or when Glasgow Coma Scale score is ≤14. 6, 7, 3

Critical Management Pitfalls to Avoid

• Never allow same-day return to activity, even if symptoms resolve 6, 3
• Do not rely on athlete self-report alone—athletes frequently minimize symptoms to return to play, particularly males 6
• Do not miss delayed symptom onset—patients with delayed symptoms are significantly less likely to be immediately removed from play (29.2% vs 71.6% immediate removal rate) 8
• Do not use cervical collars routinely in first aid settings—they may increase intracranial pressure and cause harm 1

Follow-Up Requirements

Arrange follow-up with a healthcare professional trained in concussion management within 24-48 hours, even if symptoms appear mild. 6, 7 Continue monitoring for several days as symptoms may evolve over minutes to hours following injury. 2, 6