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This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.
The Bottom Line
- TBI severity by GCS: mild 13-15, moderate 9-12, severe <=8.
- Prevent secondary brain injury: avoid hypoxia, hypotension, hypercapnia, hypoglycemia, fever, and seizures.
- Head CT is first-line imaging for clinically significant acute TBI.
- Epidural hematoma: lucid interval, biconvex lens on CT, often middle meningeal artery.
- Subdural hematoma: crescent-shaped bleed, bridging veins, common in elderly, alcohol use, anticoagulation, and abuse.
Overview
Traumatic brain injury includes concussion, contusion, diffuse axonal injury, skull fracture, epidural hematoma, subdural hematoma, subarachnoid hemorrhage, and intraparenchymal hemorrhage. Primary injury occurs at impact; emergency management focuses on preventing secondary injury from hypoxia, hypotension, raised intracranial pressure, seizures, fever, and metabolic derangement.
Epidemiology
TBI is a major cause of death and disability in the United States. Falls predominate in older adults and young children, while motor vehicle collisions, sports, assaults, and firearms contribute substantially. Anticoagulant use and advanced age increase intracranial hemorrhage risk after apparently minor trauma.
Clinical Features
Symptoms
Headache, vomiting, amnesia, dizziness, confusion, or loss of consciousness
Seizure after head injury
Worsening headache, repeated vomiting, drowsiness, agitation, or focal weakness
Clear rhinorrhea or otorrhea suggesting CSF leak
Concussion symptoms: headache, photophobia, nausea, concentration difficulty, sleep disturbance, emotional lability
Signs
GCS <=8, declining GCS, unequal pupils, or focal neurologic deficit
Signs of basilar skull fracture: Battle sign, raccoon eyes, hemotympanum, CSF leak
Cushing triad: hypertension, bradycardia, irregular respirations — late sign of raised ICP
Scalp hematoma, skull depression, penetrating injury, or open fracture
Investigations
First-line
Non-contrast CT headBest initial imaging for acute intracranial hemorrhage, skull fracture, mass effect, herniation, and hydrocephalus.
GCS and neurologic examSerial GCS, pupils, motor/sensory exam, cranial nerves, and signs of deterioration.
Glucose, CBC, BMP, coagulation studiesIdentify hypoglycemia, anemia, electrolyte disturbance, and anticoagulation/coagulopathy.
Second-line
CT cervical spineIndicated with high-risk mechanism, midline tenderness, neurologic deficit, intoxication, altered mental status, or distracting injury.
Repeat CT headFor neurologic deterioration, anticoagulation, significant hemorrhage, or neurosurgical guidance.
MRI brainMore sensitive for diffuse axonal injury and subacute findings; not usually first-line in unstable acute TBI.
Specialist
Intracranial pressure monitoringConsider in severe TBI with abnormal CT or high-risk normal CT features; neurosurgical/ICU management.
Management
ACS Best Practices Guidelines for Traumatic Brain Injury and Brain Trauma Foundation principles1
Initial stabilization
- Airway protection with cervical spine precautions; intubate for GCS <=8, inability to protect airway, or severe agitation preventing care.
- Avoid hypoxia; maintain oxygenation and normocapnia after intubation.
- Avoid hypotension; maintain adequate SBP/MAP for cerebral perfusion.
- Treat hypoglycemia, severe hyperglycemia, hyperthermia, and seizures.
- Elevate head of bed to 30 degrees and keep neck midline if increased ICP suspected.
2
Intracranial hemorrhage / raised ICP
- Immediate neurosurgical consultation for epidural, large subdural, depressed skull fracture, penetrating injury, mass effect, or deterioration.
- Hyperosmolar therapy for herniation or severe ICP: hypertonic saline or mannitol if hemodynamically stable.
- Brief hyperventilation can be used as a temporizing measure for impending herniation only.
- Reverse anticoagulation urgently when intracranial hemorrhage is present.
- Seizure prophylaxis for severe TBI or high-risk intracranial bleeding, commonly levetiracetam for 7 days.
3
Concussion / mild TBI
- Discharge only if low risk, normal mental status, reliable observation, and no concerning CT/clinical features.
- Brief cognitive and physical rest for 24-48 hours, then gradual return to activity.
- No same-day return to play after suspected concussion.
- Strict return precautions for worsening headache, vomiting, confusion, seizure, weakness, or drowsiness.
4
Disposition
- ICU for severe TBI, abnormal CT with risk of deterioration, intubation, or need for ICP monitoring.
- Transfer to trauma/neurosurgical center if local neurosurgical capability is unavailable.
- Consider non-accidental trauma in children with inconsistent history, retinal hemorrhages, or subdural bleeding.
Complications
- Herniation: Uncal herniation causes ipsilateral blown pupil and contralateral weakness
- Seizures: Early post-traumatic seizures occur within 7 days
- Diffuse axonal injury: Coma out of proportion to CT findings after acceleration-deceleration injury
- Post-concussion syndrome: Persistent headache, dizziness, mood, sleep, and cognitive symptoms
- Neuroendocrine dysfunction: Pituitary injury can cause diabetes insipidus or hypopituitarism
USMLE Step 2 CK Exam Tips
- 1GCS <=8 = intubate.
- 2Epidural hematoma = lucid interval + biconvex lens-shaped bleed.
- 3Subdural hematoma = crescent bleed from bridging veins; elderly/alcohol/anticoagulation/high-risk infants.
- 4Diffuse axonal injury = coma after high-speed MVC with initially normal or subtle CT; MRI shows lesions at gray-white junction/corpus callosum.
- 5Do not perform lumbar puncture when increased ICP or mass lesion is suspected.
- 6Cushing triad is late; act before it appears.
- 7Hyperventilation is temporary rescue for herniation, not routine TBI management.
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