Overview

Head Injury

Quick Reference

Critical Alerts

GCS ≤8 = severe TBI: Intubate for airway protection
Cushing's triad: Hypertension, bradycardia, irregular respirations = impending herniation
Pupils: Unilateral dilation suggests uncal herniation - urgent neurosurgery
Anticoagulated patients: Much higher risk of intracranial hemorrhage - low threshold for CT
Clinical decision rules: Canadian CT Head Rule and PECARN help reduce unnecessary imaging
Secondary injury prevention: Avoid hypotension, hypoxia, hyperthermia, hypoglycemia

Key Diagnostics

Test	Finding	Significance
GCS	Score 3-15	Severity classification
CT Head Non-Contrast	Hemorrhage, fracture, mass effect	Immediate imaging for moderate-severe
Pupils	Size, reactivity	Signs of herniation
Coagulation studies	PT/INR	Anticoagulation status
Blood glucose	Hypoglycemia	Treatable cause of altered mental status

Emergency Treatments

Condition	Treatment	Dose/Details
Elevated ICP	Mannitol	1-1.5 g/kg IV
Alternative ICP	Hypertonic saline	23.4% 30mL or 3% 250mL
Herniation	Hyperventilation (temporary)	PaCO2 30-35 mmHg
Coagulopathy reversal	4-factor PCC (warfarin)	25-50 units/kg
Seizure	Levetiracetam	20 mg/kg IV (max 3g)
Hypotension	IV fluids, vasopressors	MAP >80 mmHg, CPP >0

Definition

Overview

Head injury encompasses any trauma to the scalp, skull, or brain, ranging from minor lacerations to severe traumatic brain injury (TBI). TBI specifically refers to brain dysfunction caused by an external mechanical force. Emergency management focuses on identifying life-threatening injuries, preventing secondary brain injury, and facilitating appropriate neurosurgical intervention.

Classification

By Severity (Glasgow Coma Scale):

Category	GCS	Description
Mild TBI (Concussion)	13-15	Most common (80%); brief or no LOC
Moderate TBI	9-12	May require monitoring; variable outcomes
Severe TBI	3-8	Coma; requires ICU, possible surgery; high morbidity/mortality

By Pathology:

Type	Description	Features
Epidural hematoma (EDH)	Arterial bleeding between skull and dura	"Lucid interval," lens-shaped on CT
Subdural hematoma (SDH)	Venous bleeding between dura and brain	Crescent-shaped, crosses suture lines
Subarachnoid hemorrhage (SAH)	Blood in subarachnoid space	Trauma #1 cause of SAH
Intraparenchymal hemorrhage	Contusion or hematoma within brain	Common in frontal/temporal lobes
Diffuse axonal injury (DAI)	Shearing injury to axons	Often from acceleration-deceleration; poor prognosis
Skull fracture	Linear, depressed, basilar, open	May require surgical intervention

By Mechanism:

Primary injury: Direct damage at time of impact (not modifiable)
Secondary injury: Subsequent damage from hypoxia, hypotension, inflammation, edema (preventable)

Epidemiology

Incidence: 2.5 million ED visits annually in US; 300,000 hospitalizations
Mortality: 50,000 deaths/year in US
Leading causes: Falls (50%), MVCs (25%), struck by/against (15%), assault (10%)
Age groups: Bimodal - young adults (15-24) and elderly (>75)
Gender: Males 3× more likely to die from TBI

Etiology and Risk Factors

Mechanism	Common Causes
Falls	Leading cause, especially elderly
Motor vehicle crashes	High-energy, often severe injuries
Violence/Assault	Intentional injury, consider abuse
Sports injuries	Contact sports, falls from bicycles
Penetrating trauma	GSW, stab wounds

High-Risk Populations:

Elderly (>65): Falls, anticoagulation, brain atrophy
Children (<4): Falls, abuse (shaken baby syndrome)
Substance users: Impaired judgment, falls
Athletes: Contact sports, cumulative injury
Anticoagulated patients: Higher bleeding risk

Pathophysiology

Primary vs Secondary Brain Injury

Primary Injury:

Direct mechanical damage at time of impact
Neuronal injury, vascular disruption, axonal shearing
Not reversible; prevention is only intervention

Secondary Injury (Occurs Minutes to Days After):

Factor	Mechanism	Prevention
Hypoxia	Reduced oxygen delivery → neuronal death	Maintain SpO2 >4%
Hypotension	Reduced cerebral perfusion	SBP >90 mmHg, MAP >0
Hyperthermia	Increased metabolic demand	Active cooling if febrile
Hypoglycemia	Cellular energy failure	Maintain glucose 80-180
Hyperglycemia	Osmotic, inflammatory effects	Avoid extreme hyperglycemia
Intracranial hypertension	Reduced CPP, herniation	ICP monitoring, interventions
Seizures	Increased metabolic demand	Prophylaxis in high-risk
Infection	Meningitis, abscess	Prophylaxis for open fractures

Cerebral Perfusion and ICP

Monroe-Kellie Doctrine:

Fixed intracranial volume = brain (~80%) + blood (~10%) + CSF (~10%)
Increase in one component → increase in ICP → decrease in perfusion

Cerebral Perfusion Pressure (CPP):

CPP = MAP - ICP
Normal CPP > 60 mmHg (some target 60-70)
Goal: Maintain CPP to prevent ischemia

Autoregulation:

Normal cerebral blood flow maintained with MAP 50-150 mmHg
Lost after TBI → brain vulnerable to BP changes

Herniation Syndromes

Type	Pathology	Signs
Uncal	Medial temporal lobe through tentorium	Ipsilateral dilated pupil (CN III), contralateral hemiparesis
Central	Bilateral downward displacement	Bilateral pupil dilation, posturing → death
Tonsillar	Cerebellar tonsils through foramen magnum	Respiratory arrest, death
Subfalcine	Cingulate gyrus under falx	Contralateral leg weakness (ACA compression)

Clinical Presentation

History (AMPLE + Mechanism)

Mechanism Details:

AMPLE:

Symptoms:

Physical Examination

Primary Survey (ABCDE):

Glasgow Coma Scale:

Component	Response	Score
Eye Opening	Spontaneous / To voice / To pain / None	4/3/2/1
Verbal	Oriented / Confused / Inappropriate / Incomprehensible / None	5/4/3/2/1
Motor	Obeys / Localizes / Withdraws / Flexion / Extension / None	6/5/4/3/2/1

Pupil Examination:

Finding	Significance
Unilateral dilated, unreactive	Ipsilateral uncal herniation (CN III compression)
Bilateral dilated, fixed	Bilateral herniation, severe hypoxia, death imminent
Bilateral pinpoint	Pontine lesion, opioid intoxication
Hippus (varying)	Normal variant or early herniation

Signs of Basilar Skull Fracture:

Signs of Elevated ICP:

What happened? (Fall, MVC, assault, sports)

Common presentation.

Height of fall or speed of impact

Common presentation.

Loss of consciousness? Duration?

Common presentation.

Post-traumatic amnesia?

Common presentation.

Seizure activity?

Common presentation.

Prior neurosurgery or VP shunt?

Common presentation.

Red Flags

Immediate Life Threats

Finding	Concern	Action
GCS ≤8	Severe TBI, airway at risk	Intubate, CT, neurosurgery
Unilateral dilated pupil	Uncal herniation	Hyperventilation, mannitol, emergent surgery
Cushing's triad	Impending herniation	ICP reduction, emergent surgery
Rapidly declining GCS	Expanding hematoma	Repeat CT, surgery
Open skull fracture	Infection risk, brain exposure	Antibiotics, surgery
Penetrating injury	Active hemorrhage, object in situ	Do not remove object, surgery

High-Risk Features for Intracranial Injury

LOC >5 minutes
Post-traumatic amnesia >4 hours
Focal neurological deficit
Skull fracture
Coagulopathy or anticoagulation
Age >65 years
Two or more episodes of vomiting
Dangerous mechanism (pedestrian struck, ejection, fall >5 feet)
GCS <15 at 2 hours post-injury

Differential Diagnosis

Considerations Beyond Traumatic Injury

Diagnosis	Clinical Clues	Evaluation
Spontaneous ICH	Risk factors for stroke, sudden headache	May have precipitated the fall
Syncope → fall	Pre-syncopal symptoms, cardiac history	ECG, orthostatics
Hypoglycemia	Known diabetic, symptoms before fall	Fingerstick glucose
Seizure	Witnessed tonic-clonic activity, post-ictal	EEG, history
Alcohol/drug intoxication	History, toxidrome	Tox screen
Stroke → fall	Focal deficits, risk factors	CT/MRI
Elder abuse	Pattern of injuries, social situation	Social work, forensic evaluation

Diagnostic Approach

Clinical Decision Rules

Canadian CT Head Rule (Adults with Minor Head Injury, GCS 13-15): CT if ANY high-risk criterion (for neurosurgical intervention):

GCS <15 at 2 hours post-injury
Suspected open or depressed skull fracture
Any sign of basilar skull fracture
≥2 episodes of vomiting
Age ≥65 years

CT if ANY medium-risk criterion (for brain injury on CT):

Retrograde amnesia ≥30 minutes before impact
Dangerous mechanism (pedestrian struck, ejection, fall >3 feet or >5 stairs)

Not applicable if: GCS <13, age <16, anticoagulation, obvious skull fracture

PECARN (Pediatric <18 years):

Validated for children; used to avoid unnecessary CT

Imaging Studies

CT Head Non-Contrast (Gold Standard):

Indications: All moderate-severe TBI, high/medium risk by clinical rules, anticoagulated, coagulopathic
Findings to look for:
- Epidural hematoma: Lens-shaped, doesn't cross sutures
- Subdural hematoma: Crescent, crosses sutures
- Subarachnoid blood: Hyperdense in sulci
- Contusion: Hemorrhage within parenchyma
- Midline shift: >5mm often surgical indication
- Effacement of ventricles, cisterns

CT Angiography:

Suspected vascular injury (dissection, traumatic aneurysm)
Penetrating trauma

MRI Brain:

Better for diffuse axonal injury, subacute/chronic bleeds
Not emergent; usually delayed

Laboratory Studies

Test	Purpose
Blood glucose	Exclude hypoglycemia
CBC	Baseline Hgb, platelet count
PT/INR, aPTT	Coagulopathy, anticoagulation
Type and Screen	For potential surgery
Blood alcohol, drug screen	Contributing factors
LFTs	If concern for hepatic coagulopathy

Treatment

Principles of Management

Prevent secondary injury: Avoid hypoxia, hypotension, hyperthermia
Early airway management: Intubate for GCS ≤8
Control ICP: Medical and surgical interventions
Reverse coagulopathy: Critical for anticoagulated patients
Neurosurgical consultation: Early for significant findings

Airway Management

Indications for Intubation:

GCS ≤8
Inability to protect airway
Combativeness requiring sedation
Need for hyperventilation
Hypoxia not corrected with supplemental O2
Transport of severe TBI

RSI Considerations in TBI:

Agent	Dose	Notes
Lidocaine	1.5 mg/kg IV	May blunt ICP response (controversial)
Fentanyl	1-2 mcg/kg	Blunts sympathetic response
Etomidate	0.3 mg/kg	Hemodynamically neutral
Ketamine	1-2 mg/kg	Previously avoided; now acceptable
Propofol	1-2 mg/kg	Causes hypotension; use cautiously
Rocuronium	1.2 mg/kg	Preferred paralytic

Hemodynamic Management

Blood Pressure Goals:

Age	Target SBP
Adults	>90 mmHg (>00 associated with better outcomes)
Elderly	Consider higher targets due to chronic HTN

Hypotension + TBI = doubles mortality
Bolus crystalloid, then vasopressors if needed (norepinephrine)

CPP Goal: 60-70 mmHg (MAP - ICP)

ICP Management

Tier 1 (Basic Measures):

Head of bed 30° (improves venous drainage)
Head midline (no jugular compression)
Loosen cervical collar if too tight
Avoid hyperthermia
Adequate sedation and analgesia
Avoid hypoxia and hypotension

Tier 2 (Osmotherapy):

Agent	Dose	Mechanism	Notes
Mannitol	1-1.5 g/kg IV	Osmotic diuresis	Monitor osmolality <320
Hypertonic saline (3%)	250-500 mL	Draws fluid intravascularly	Can repeat
Hypertonic saline (23.4%)	30 mL	Rapid ICP reduction	Via central line preferred

Tier 3 (Rescue Therapies):

Hyperventilation: PaCO2 30-35 (transient, rescue only - causes vasoconstriction)
Barbiturate coma: Pentobarbital for refractory ICP
Decompressive craniectomy: Surgical removal of bone flap

Coagulopathy Reversal

Agent	Reversal	Dose
Warfarin	4-factor PCC + Vitamin K	PCC 25-50 units/kg; VitK 10mg IV
Dabigatran	Idarucizumab	5g IV
Factor Xa inhibitors	Andexanet alfa or 4F-PCC	Per protocol
Heparin	Protamine	1mg per 100 units heparin
Antiplatelet (emergency surgery)	Platelet transfusion	1-2 units

Seizure Management

Prophylaxis Indications:

Depressed skull fracture
Penetrating injury
Severe TBI (GCS ≤10)
Epidural, subdural, or intracerebral hematoma
Within 7 days of injury (reduces early seizures)

Prophylaxis Regimen:

Levetiracetam 20 mg/kg IV (max 3g) then 500-1000 mg BID × 7 days
Alternative: Phenytoin 20 mg/kg IV, then maintenance

Treatment of Active Seizure:

Benzodiazepines (lorazepam 4 mg IV, midazolam 10 mg IM)
Then levetiracetam or phenytoin loading dose

Surgical Management

Indications for Surgery:

Lesion	Surgical Indication
Epidural hematoma	>30 mL, thickness >15 mm, midline shift > mm
Subdural hematoma	Thickness >10 mm, midline shift > mm, GCS drop ≥2
Intraparenchymal	Volume >0 mL, progressive deterioration
Depressed skull fracture	Depression > thickness of skull, open, cosmetic
Posterior fossa lesion	Deterioration, ventricular obstruction

Neurosurgical Procedures: A Guide for Non-Surgeons

Understanding what happens in theatre helps in post-op care.

1. Burr Hole Evacuation (For Chronic SDH)

Indication: Liquefied Chronic Subdural Haematoma.
Position: Supine, head turned.
Steps:
1. Incision over the parietal boss (or maximal thickness).
2. Drill: Single burr hole through skull.
3. Dura: Incised (cruciate).
4. Flow: Dark "motor oil" fluid drains out under pressure.
5. Irrigation: Warm saline until clear.
6. Drain: Subdural drain left in situ for 24-48h.
Post-Op: Flat bed rest for 24h to encourage brain re-expansion.

2. Craniotomy (For Acute EDH/SDH)

Indication: Solid clot (Acute blood is jelly-like and won't drain through a hole).
The "Question Mark" Incision: Large flap starting at the tragus, curving around the parietal eminence to the midline.
Bone Flap: Removed with craniotome.
Evacuation: Suction/Irrigation of clot. Diathermy of bleeding vessel (e.g., Middle Meningeal Artery).
Closure: Bone flap replaced and fixed with mini-plates.

3. Decompressive Craniectomy (For Intractable ICP)

Concept: When the brain is swollen (edema) and ICP is >25mmHg despite medical therapy, the skull is a fixed box killing the brain. We remove the lid.
Procedure:
- Large Hemicraniectomy (12-15cm).
- Bone is NOT replaced. It is stored (frozen) or discarded (titanium plate later).
- Durotomy: The dura is opened widely to allow the brain to herniate OUTWARDS through the defect, relieving pressure on the brainstem.
Post-Op: Patient has a soft spot. "Helmet Sign" - patient must wear a helmet when mobilized until Cranioplasty (months later).

Critical Care: Advanced ICP Management (The "Lund Protocol" Concept)

Tier 3: The "Metabolic Suppression" Phase

When Mannitol and Saline fail.

Barbiturate Coma (Thiopental):
- Mechanism: Reduces cerebral metabolic rate (CMRO2) by 50%.
- Side Effect: Profound hypotension (requires vasopressors) and immune suppression.
- Monitoring: EEG required (aim for Burst Suppression).
Targeted Temperature Management (Hypothermia):
- Target: 33-35°C.
- Evidence: Controversial (Eurotherm trial showed harm?), but still used in specific refractory cases.
- Risk: Coagulopathy, Infection.

Disposition

Admission Criteria

GCS <15 or any neurological deficit
Intracranial hemorrhage or skull fracture on CT
Persistent symptoms (severe headache, vomiting)
Anticoagulated with positive CT or clinical concern
No reliable observer for discharge
Suspected child abuse

ICU Criteria

GCS ≤8 (severe TBI)
Need for ICP monitoring
Intubated
Hemodynamic instability
Large intracranial hemorrhage
Post-operative neurosurgical care

Discharge Criteria (Mild TBI)

GCS 15
Normal neurological examination
Normal CT (if obtained) or low-risk by clinical decision rules
Symptoms improving
Reliable adult to observe for 24 hours
Understands return precautions

Follow-Up

Situation	Follow-Up
Mild TBI with positive CT	Neurosurgery within 1-2 weeks
Mild TBI with negative CT	PCP in 1-2 weeks; sports medicine if athlete
Anticoagulated with positive CT	Neurosurgery urgent; hematology
Moderate TBI	Rehabilitation, neurology
Severe TBI	Intensive rehabilitation planning

Patient Education

Discharge Instructions for Mild TBI (Concussion)

What to Expect:

Headache, fatigue, difficulty concentrating common for days to weeks
Most symptoms resolve within 7-10 days; some take longer

Activity Restrictions:

Physical and cognitive rest for 24-48 hours
Gradual return to normal activities as tolerated
No contact sports until cleared by physician
No alcohol for 48 hours minimum
No driving until symptom-free

Return Precautions (Seek Immediate Care If):

Worsening or severe headache
Repeated vomiting (>2 times)
Increasing confusion or drowsiness
Difficulty waking up
Seizures or convulsions
One pupil larger than the other
Slurred speech
Weakness or numbness in extremities
Clear fluid from nose or ear
Loss of consciousness

Observer Instructions:

Check on patient every 2-4 hours for first 24 hours (can awaken for checks)
Watch for warning signs above
Call 911 if concerned

Special Populations

Anticoagulated Patients

Much higher risk of intracranial hemorrhage (even minor trauma)
Lower threshold for CT imaging
Repeat CT at 6-24 hours if initial negative but mechanism/concern
Early reversal of anticoagulation for bleeding
Hematology and neurosurgery input

Elderly (>65 Years)

Brain atrophy increases subdural bleeding risk
More likely on anticoagulation
Falls are leading cause
Higher mortality
Consider abuse or neglect

Pediatric

Fontanelles (if open) may mask ICP
PECARN criteria validated for imaging decisions
Consider non-accidental trauma if: Inappropriate history, multiple injuries, retinal hemorrhages
More resilient brain but vulnerable to DAI

Athletes

Gradual return-to-play protocols
No same-day return after concussion
Post-concussion syndrome more common with multiple injuries
Neuropsychological testing may guide return

Penetrating Trauma

Do not remove impaled objects
Antibiotics for infection prophylaxis
CT to evaluate trajectory
Neurosurgical emergency

Quality Metrics

Performance Indicators

Metric	Target	Rationale
CT within 25 min for severe TBI	100%	Rapid diagnosis
Hypoxia avoided (SpO2 >0%)	100%	Prevent secondary injury
Hypotension avoided (SBP >0)	100%	Prevent secondary injury
Neurosurgery consult for surgical lesion	100%	Timely intervention
Seizure prophylaxis for high-risk	>0%	Prevent early seizures
Coagulopathy reversal for anticoagulated	100%	Reduce hematoma expansion

Documentation Requirements

Mechanism of injury
GCS (individual components)
Pupil examination
Neurological examination
Medications (especially anticoagulants)
CT interpretation
ICP management if applicable
Neurosurgical consultation
Disposition plan and return instructions

Key Clinical Pearls

Diagnostic Pearls

GCS is predictive but not perfect: Serial exams are key
Lucid interval is classic for EDH: But don't rely on it
"Doesn't need CT" doesn't mean "doesn't have TBI": Clinical rules help
Elderly + anticoagulation + fall = CT: Even if feeling fine
Look for the cause of the fall: May be cardiac, neuro, or metabolic
Basilar skull fracture signs may be delayed: Check at 12-24 hours

Treatment Pearls

Hypotension kills TBI patients: Aggressive resuscitation
Intubate at GCS ≤8: Don't wait for aspiration
Hyperventilate only as bridge to surgery: Causes vasoconstriction
Mannitol or HTS for herniation: Have ready at bedside
Reverse anticoagulation immediately for ICH: Don't wait for surgery
Ketamine is safe in TBI: Previous concerns unfounded

Disposition Pearls

Reliable observer is essential for discharge: Must monitor for deterioration
Concussion symptoms can persist: Set expectations
Return-to-play requires stepwise progression: Not same-day
Repeat imaging in anticoagulated: Low threshold
Consider rehab early: For moderate-severe TBI

References

Carney N, et al. Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition. Neurosurgery. 2017;80(1):6-15.
Stiell IG, et al. The Canadian CT Head Rule for patients with minor head injury. Lancet. 2001;357(9266):1391-1396.
Kuppermann N, et al. (PECARN). Identification of children at very low risk of clinically important brain injuries. Lancet. 2009;374(9696):1160-1170.
Hawryluk GW, et al. Management of severe traumatic brain injury: a synopsis of the Brain Trauma Foundation Guidelines. Ann Neurol. 2015;82(5):720-737.
Chesnut RM, et al. A Trial of Intracranial-Pressure Monitoring in Traumatic Brain Injury. N Engl J Med. 2012;367:2471-2481.
Collaborators CRASH-3. Effects of tranexamic acid on death, disability, vascular occlusive events and other morbidities in patients with acute traumatic brain injury. Lancet. 2019;394(10210):1713-1723.
McCrory P, et al. Consensus statement on concussion in sport. Br J Sports Med. 2017;51(11):838-847.
UpToDate. Initial management of moderate to severe traumatic brain injury. 2024.

Test

Finding

Significance

GCS

Score 3-15

Severity classification

CT Head Non-Contrast

Hemorrhage, fracture, mass effect

Immediate imaging for moderate-severe

Pupils

Size, reactivity

Signs of herniation

Coagulation studies

PT/INR

Anticoagulation status

Blood glucose

Hypoglycemia

Treatable cause of altered mental status

Condition

Treatment

Dose/Details

Elevated ICP

Mannitol

1-1.5 g/kg IV

Alternative ICP

Hypertonic saline

23.4% 30mL or 3% 250mL

Herniation

Hyperventilation (temporary)

PaCO2 30-35 mmHg

Coagulopathy reversal

4-factor PCC (warfarin)

25-50 units/kg

Seizure

Levetiracetam

20 mg/kg IV (max 3g)

Hypotension

IV fluids, vasopressors

MAP >80 mmHg, CPP >0

Diagnostic Pearls

GCS is predictive but not perfect: Serial exams are key
Lucid interval is classic for EDH: But don't rely on it
"Doesn't need CT" doesn't mean "doesn't have TBI": Clinical rules help
Elderly + anticoagulation + fall = CT: Even if feeling fine
Look for the cause of the fall: May be cardiac, neuro, or metabolic
Basilar skull fracture signs may be delayed: Check at 12-24 hours

Treatment Pearls

Hypotension kills TBI patients: Aggressive resuscitation
Intubate at GCS ≤8: Don't wait for aspiration
Hyperventilate only as bridge to surgery: Causes vasoconstriction
Mannitol or HTS for herniation: Have ready at bedside
Reverse anticoagulation immediately for ICH: Don't wait for surgery
Ketamine is safe in TBI: Previous concerns unfounded

Disposition Pearls

Reliable observer is essential for discharge: Must monitor for deterioration
Concussion symptoms can persist: Set expectations
Return-to-play requires stepwise progression: Not same-day
Repeat imaging in anticoagulated: Low threshold
Consider rehab early: For moderate-severe TBI