Concussion Workup
The workup for suspected concussion is primarily clinical—based on history and physical examination—with CT head imaging reserved only for patients meeting validated high-risk criteria (CCHR or NOC) to rule out intracranial injury requiring neurosurgical intervention. 1
Initial Assessment: Rule Out Serious Injury First
Before diagnosing concussion, you must exclude:
- Intracranial hemorrhage requiring neurosurgical intervention
- Cervical spine injury 2
This is your first priority—concussion is a diagnosis of exclusion after ruling out life-threatening pathology.
Clinical Diagnosis
Concussion remains a clinical diagnosis—there is no imaging or laboratory test that diagnoses concussion itself. 3, 2
Key History Elements:
- Mechanism of injury: Direct or indirect trauma to the head causing rotational/angular forces 4
- Temporal relationship: Symptoms must have clear onset after the traumatic event 4
- Loss of consciousness or amnesia (though neither is required for diagnosis)
- Symptom inventory: Headache (most common), dizziness, nausea/vomiting, confusion, balance problems, visual disturbances, cognitive difficulties, emotional changes, sleep disturbances 4, 5
Physical Examination Components:
The examination should systematically evaluate 6:
- Mental status: Orientation, immediate and delayed recall, concentration, mood, affect
- Cranial nerves (all 12)
- Ocular examination: Pupillary reactivity, extraocular movements, visual tracking, convergence
- Balance testing: Static (Romberg) or dynamic (tandem gait)
- Cervical spine: Inspection for trauma/tenderness, range of motion, Spurling maneuver
- Motor strength and deep tendon reflexes
- Coordination testing
CT Head Imaging: When to Order
Do NOT routinely order CT for concussion diagnosis—imaging has no role in diagnosing concussion itself. 2 CT is only indicated to rule out intracranial injury requiring intervention.
Use Validated Decision Rules:
Canadian CT Head Rule (CCHR) - Order CT if ANY high-risk factor present 1:
- Failure to reach GCS 15 within 2 hours
- Suspected open skull fracture
- Signs of basal skull fracture (hemotympanum, raccoon eyes, Battle's sign, CSF leak)
- Vomiting ≥2 episodes
- Age >64 years
New Orleans Criteria (NOC) - Order CT if ANY factor present (in patients with GCS 15 and LOC/amnesia) 1:
- Headache
- Vomiting
- Age >60 years
- Drug or alcohol intoxication
- Deficits in short-term memory
- Physical evidence of trauma above clavicles
- Posttraumatic seizure
These rules are 98-100% sensitive for clinically important brain injury. The CCHR high-risk criteria are 100% sensitive for neurosurgical intervention. 1
What NOT to Order
The following have no role in initial concussion workup 7:
- MRI head
- CT angiography (unless vascular injury suspected)
- Skull radiographs (replaced by CT)
- SPECT imaging
- MR spectroscopy
- Functional MRI
Repeat Imaging
Do not routinely repeat CT in patients with normal initial CT and stable neurologic examination. 7 The risk of deterioration with both normal CT and normal neurologic exam is extremely low (0.006%). 7
Consider repeat imaging only if:
- Neurologic deterioration occurs
- GCS remains <15 after 24 hours despite normal initial CT 7
Adjunctive Assessment Tools
While not required for diagnosis, these can supplement clinical evaluation 3, 8:
- Symptom checklists (e.g., SCAT5, Post-Concussion Symptom Scale)
- Cognitive testing (baseline vs. post-injury neuropsychological testing)
- Balance assessment tools (BESS)
- Sideline assessment tools (for sports-related injury)
Common Pitfalls
- Ordering unnecessary CT scans: Use validated decision rules—not every head injury needs imaging
- Expecting imaging to diagnose concussion: CT/MRI are normal in concussion; they only rule out structural injury
- Delaying removal from risk: If concussion suspected in an athlete, immediate removal from play is mandatory 4
- Overlooking cervical spine injury: Always assess the neck in head trauma 2
- Missing subtle symptoms: Concussion symptoms can be nonspecific and easily overlooked in the ED setting 2