Head Trauma & Intracranial Hypertension
Evidence-based emergency management of traumatic brain injury (TBI): Canadian CT Head Rule, PECARN pediatric head injury algorithm, distinguishing epidural vs subdural vs subarachnoid hematomas, ICP reduction strategies, and concussion guidelines.
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In severe traumatic brain injury, the primary goal of the emergency physician is preventing SECONDARY BRAIN INJURY: avoid hypotension (maintain SBP >= 100 mmHg if age 50–69, or >= 110 mmHg if age 15–49 or >= 70) and avoid hypoxia (SpO2 >= 90%). A single episode of hypotension doubles TBI mortality. Use the Canadian CT Head Rule in adults and PECARN in children to guide neuroimaging. For acute intracranial herniation, administer 3% Hypertonic Saline (250 mL IV bolus) and immediately mobilize neurosurgery.
Traumatic brain injury (TBI) causes primary mechanical damage (contusions, lacerations, hemorrhage) followed by secondary ischemic, inflammatory, and cytotoxic cascades. Rapid non-contrast head CT differentiates operative intracranial hematomas:
| Intracranial Lesion | Vascular Source & Mechanism | Classic CT Morphology | Clinical Presentation & Surgical Trigger |
|---|---|---|---|
| Epidural Hematoma (EDH) | Middle Meningeal Artery laceration associated with temporal bone / pterion fracture | Biconvex / Lenticular (lens-shaped) hyperdensity; does NOT cross cranial suture lines (dura adheres tightly to sutures) | CLASSIC LUCID INTERVAL: Brief loss of consciousness -> period of clear lucidity -> rapid neurological decline and uncal herniation. Emergent craniotomy if volume > 30 mL or midline shift > 5 mm. |
| Acute Subdural Hematoma (SDH) | Bridging cortical veins tearing across the subdural space; high-velocity trauma or falls in elderly/coagulopathic patients | Crescent-shaped hyperdensity along cerebral convexity; CROSSES cranial suture lines (limited only by dural reflections) | Progressive coma, hemiparesis. Carries high mortality (40–60%) due to underlying parenchymal injury. Emergent craniotomy if thickness > 10 mm or shift > 5 mm. |
| Traumatic Subarachnoid Hemorrhage (tSAH) | Rupture of small pial and subarachnoid vessels over cerebral convexities | Hyperdensity tracing the cortical sulci and basal cisterns | Headache, photophobia, meningismus; monitored in neuro-ICU; evaluate for secondary vasospasm. |
| Cerebral Contusion / Coup-Contrecoup | Deceleration impact of brain against rigid skull ridges (frontal poles, anterior temporal lobes) | Punctate 'salt-and-pepper' hyperdensities with surrounding hypodense edema | Can blossom/expand within 24–48 hours; repeat head CT mandatory for neurologic decline. |
Never order head CT scans indiscriminately in minor head injuries (GCS 13–15). Validated clinical decision instruments safely rule out significant intracranial injury without radiation:
| Rule / Population | High-Risk Criteria Mandating Immediate Non-Contrast Head CT | Medium-Risk / Additional Triggers |
|---|---|---|
| Canadian CT Head Rule (Adults >= 16 yr with GCS 13–15 + LOC or Amnesia) | High Risk (Requires neurosurgical intervention): 1) GCS < 15 at 2 hours post-injury; 2) Suspected open or depressed skull fracture; 3) Any sign of basal skull fracture (hemotympanum, raccoon eyes, Battle sign, CSF rhinorrhea/otorrhea); 4) >= 2 episodes of vomiting; 5) Age >= 65 years. | Medium Risk (Brain injury on CT): 1) Retrograde amnesia to event > 30 minutes; 2) Dangerous mechanism (pedestrian struck, ejection from motor vehicle, fall from elevation > 3 feet or 5 stairs). |
| PECARN Head Rule: Age < 2 Years (Pediatrics) | High Risk (4.4% risk of ciTBI): 1) GCS <= 14 or altered mental status; 2) Palpable skull fracture. | Intermediate Risk (0.9% risk): Occipital, parietal, or temporal scalp hematoma; LOC > 5 seconds; severe mechanism; not acting normally per parents. (Observe vs CT). |
| PECARN Head Rule: Age 2 to 18 Years | High Risk (4.3% risk of ciTBI): 1) GCS <= 14 or altered mental status; 2) Signs of basilar skull fracture. | Intermediate Risk: History of LOC; vomiting; severe mechanism; severe headache. (Observe vs CT). |
Primary mechanical injury occurs at the instant of trauma and cannot be reversed. Emergency management focuses entirely on preventing secondary brain injury caused by systemic insults:
| Systemic Threat | Physiological Target | Emergency Intervention | Clinical Evidence & Impact |
|---|---|---|---|
| Systemic Hypotension | Maintain SBP >= 100 mmHg (age 50–69) or SBP >= 110 mmHg (age 15–49 or >= 70) | Isotonic balanced crystalloids, PRBCs, and early Norepinephrine infusion | A single episode of SBP < 90 mmHg DOUBLES mortality in severe TBI (Brain Trauma Foundation Guidelines). |
| Hypoxemia | Maintain SpO2 >= 90% (target 94–98%); PaO2 >= 60 mmHg | High-flow oxygen; early endotracheal intubation (neuroprotective RSI) | Hypoxemia exacerbates cerebral ischemia and triples mortality when combined with hypotension. |
| Acute Elevated ICP / Herniation | Maintain CPP 60–70 mmHg (CPP = MAP - ICP); ICP < 20–22 mmHg | Hypertonic Saline (3% NaCl 250 mL IV over 10 min) OR Mannitol (0.5–1.0 g/kg IV); elevate HOB 30 degrees | Hypertonic saline preserves intravascular volume and blood pressure; preferred over mannitol in trauma. |
| Post-Traumatic Seizures | Seizure cessation and early prophylaxis | Levetiracetam (Keppra) 20–30 mg/kg IV (max 2g) loading dose | Reduces early post-traumatic seizures (first 7 days); seizures dramatically spike cerebral metabolic rate and ICP. |
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