What is the appropriate evaluation, imaging criteria, and management plan for a patient with a cerebral concussion?

Cerebral Concussion: Evaluation, Imaging, and Management

Initial Evaluation and Diagnosis

For a patient with suspected cerebral concussion, immediately assess Glasgow Coma Scale (GCS) score, document loss of consciousness duration, post-traumatic amnesia, and focal neurologic deficits to establish severity and guide imaging decisions. 1, 2

Clinical Assessment Components

• GCS scoring is mandatory at presentation: mild TBI is defined as GCS 13-15, moderate as GCS 9-12, and severe as GCS 3-8 2
• Document the following specific features: loss of consciousness ≤30 minutes, post-traumatic amnesia <24 hours, confusion/disorientation, and any transient neurologic abnormalities 2
• Headache is the most common presenting symptom, followed by dizziness, imbalance, fatigue, and cognitive impairment 3
• Perform focused neurologic examination including balance testing (BESS, Romberg, tandem gait) and cognitive assessment (SAC or SCAT2) 1

Critical Red Flags Requiring Immediate Imaging

• Focal neurologic deficit, vomiting, severe headache 1
• Age ≥65 years, GCS <15 at any point 1
• Physical signs of basilar skull fracture (Battle's sign, raccoon eyes, hemotympanum, CSF otorrhea/rhinorrhea) 1
• Coagulopathy or anticoagulant therapy 1, 2
• Dangerous mechanism of injury (ejection from vehicle, pedestrian struck, fall >3 feet or 5 stairs) 1
• Post-traumatic seizure 2

Imaging Strategy

Acute Phase (First 24-48 Hours)

Non-contrast CT head is the first-line imaging modality for acute concussion when clinical decision rules indicate risk factors, as it rapidly detects neurosurgical lesions requiring intervention. 1

• CT is mandatory if any red flag criteria are present 1, 2
• Multiplanar reformatted images increase diagnostic accuracy and should be included 1
• CT is superior for detecting acute intracranial hemorrhage, skull fractures, and herniation within the first 24-48 hours 1
• Negative predictive value of 100% for neurologic deterioration requiring surgical intervention when both CT and neurologic exam are normal 1

When NOT to Image Acutely

• Mild TBI (GCS 15) without loss of consciousness or post-traumatic amnesia AND no red flag criteria present 1
• In pediatric patients, increasing clinical observation in the emergency department can obviate CT need without substantial harm in mild TBI 1

Subacute/Chronic Phase (>2 Weeks Post-Injury)

MRI without contrast is the most appropriate imaging for subacute or chronic concussion with persistent unexplained cognitive or neurologic deficits, as it is far more sensitive than CT for detecting subtle structural injury. 1, 4

• MRI detects 6 times more microbleeds using susceptibility-weighted imaging compared to older gradient-echo sequences 1
• MRI is superior for identifying focal encephalomalacia at inferior frontal/anterior temporal lobes, white matter lesions from traumatic axonal injury, and non-hemorrhagic contusions 1, 4
• Conventional MRI should include T1-weighted, T2-weighted, T2*-weighted (gradient-echo), and diffusion-weighted imaging 1
• CT misses up to 27% of abnormalities detected on subsequent MRI 4

Advanced Imaging (Not Routinely Recommended)

• No role for routine use of CTA, MRA, FDG-PET, fMRI, MR spectroscopy, or DTI in initial acute or subacute concussion evaluation 1
• These modalities remain research tools with insufficient evidence for individual patient-level clinical decisions 1

Management Algorithm

Immediate Management (First 24-48 Hours)

Remove athlete from play immediately if concussion suspected—never allow same-day return to play. 1, 2

• Brief cognitive and physical rest (not exceeding 3 days) are key initial management components 2, 3
• Strict prolonged rest beyond 3 days worsens outcomes and should be avoided 2
• Provide patient education about expected symptom trajectory and reassurance that most symptoms resolve within 1-2 weeks 3, 5
• Monitor for deterioration: instruct patients on red flag symptoms requiring immediate return (worsening headache, repeated vomiting, seizures, focal weakness, confusion) 1

Symptom Management

• Prioritize treating symptoms with significant functional impact: headache, depression, anxiety, insomnia, vertigo 5
• Use hierarchical, sequential approach targeting one symptom domain at a time 5
• Address sleep disruption early, as it compounds other symptoms 5

Return to Activity Protocol

As symptoms resolve, gradually return to activity using individualized progression based on symptom response—rigid timelines have been abandoned. 3

• Begin gradual return only after patient is asymptomatic at rest 3
• Progress through graded activity levels, advancing only if symptoms do not recur 3
• Risk factors predicting prolonged recovery include: more severe immediate post-injury symptoms, history of multiple prior concussions, age <18 years, female sex 3, 6
• Patients with risk factors require more conservative management timelines 3

Critical Pitfalls to Avoid

Imaging Pitfalls

• Up to 5% of asymptomatic elderly patients on anticoagulation have intracranial hemorrhage after minor trauma despite normal initial CT 4
• Subdural hematomas can develop or expand in delayed fashion up to 2 months after initial trauma with normal CT, especially in elderly anticoagulated patients 4
• Only 10% of diffuse axonal injury is positive on CT because most lesions lack macroscopic hemorrhage—MRI is required for detection 4
• Do not obtain CT after negative MRI in absence of new symptoms—it adds no value and exposes patient to unnecessary radiation 4

Management Pitfalls

• Never discharge without appropriate imaging when red flag criteria are present 2
• Do not assume clinical improvement means radiographic stability—repeat imaging is often necessary if symptoms worsen 2
• Avoid minimizing injury with terms like "ding" or "bell rung" during documentation, though these terms may elicit more honest history from athletes 1
• Hypotension (SBP <90 mmHg) and hypoxia (SaO₂ <90%) dramatically worsen outcomes—maintain MAP ≥80 mmHg in severe cases 2, 7

Post-Concussive Syndrome

• Occurs in 15-20% of mild TBI patients when symptoms persist beyond 2 weeks 2
• Most common persistent symptoms: headaches, memory difficulties, impaired activities of daily living 2
• Late-phase symptoms (months to years) are highly influenced by psychosocial factors and have little specificity for brain injury 5
• Effective early phase management may prevent or limit late-phase disorder development 5