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Clinical Features and Examination of Head Injury

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1. Definitions and Classification

• Rosen's Emergency Medicine, p. 367

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2. The Glasgow Coma Scale (GCS)

• The motor component is the strongest single predictor of outcome after TBI.
• GCS does not replace a full neurologic examination.
• Adams & Victor's Principles of Neurology, 12th ed., p. 899

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3. Symptoms by Severity

A. Mild TBI / Concussion (GCS 13-15)

1. Loss of consciousness (LOC) < 30 minutes, or decreased level of consciousness
2. Post-traumatic amnesia < 24 hours (retrograde + anterograde)
3. Alteration in mental state at time of injury: feeling dazed, disoriented, confused, "seeing stars," foggy, slowed thinking
4. Neurologic deficits (weakness, loss of balance, vision change, sensory loss) - may be transient

• Headache (most common)
• Giddiness/dizziness
• Nausea and vomiting
• Amnesia (circumscribed confusional state with repetitive questioning)
• Fatigability, mental fogginess
• Insomnia, irritability, nervousness (post-concussive syndrome)
• "Dazed" appearance, difficulty concentrating

Even a brief stunning ("saw stars") with no LOC warrants monitoring for late epidural/subdural hematoma.

• Rosen's Emergency Medicine, p. 367; Adams & Victor, p. 899

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B. Moderate TBI (GCS 9-12)

• Drowsiness, lethargy (arousable from deep sleep, but lapses back to minimal responsiveness)
• Persistent headache
• Vomiting (particularly important - associated with increased risk of skull fracture and intracranial bleeding)
• Confusion, disorientation
• May lie down and appear somnolent

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C. Severe TBI (GCS 3-8)

• Coma: unresponsive to verbal or physical stimulation
• Absent or abnormal motor responses (decerebrate or decorticate posturing)
• Pupillary abnormalities (fixed, dilated - indicates herniation)
• Loss of brainstem reflexes
• Abnormal respiratory patterns (Cheyne-Stokes, central hyperventilation, apneusis)
• Cushing's triad: hypertension + bradycardia + irregular respiration = sign of raised ICP / impending herniation

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4. Signs of Raised Intracranial Pressure (ICP)

• Severe, worsening headache
• Vomiting (often projectile, without nausea)
• Altered/declining conscious level (falling GCS)
• Papilloedema (fundoscopy)
• Cushing's triad (late sign: hypertension, bradycardia, irregular breathing)
• Unilateral pupil dilatation and loss of light reflex (CN III compression by uncal herniation)
• Contralateral hemiparesis

• Bulging anterior fontanelle
• Sunset sign (downward deviation of eyes)
• Irritability, high-pitched cry
• Poor feeding
• Head circumference increase
• Papilloedema
• Rosen's Emergency Medicine, p. 3138

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5. Clinical Examination - Systematic Approach

Step 1: Primary Survey - ABCDE

• Airway patency (with cervical spine immobilization)
• Breathing - look for abnormal respiratory patterns
• Circulation - hypotension and hypoxia are key causes of secondary brain injury
• Disability - rapid neurologic status using GCS or AVPU scale
• Exposure

Cerebral Perfusion Pressure (CPP) = MAP - ICP. Target CPP > 40 mmHg and ICP < 20 mmHg.

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Step 2: Mental Status Assessment

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Step 3: Head Examination

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Step 4: Neurological Examination

• Size, symmetry, reactivity to light
• Unilateral fixed dilated pupil = uncal herniation (CN III compression) until proven otherwise
• Bilateral fixed dilated pupils = severe brain injury / bilateral herniation

• Ocular movements, gaze deviation ("eyes look toward the lesion" in frontal lobe injury)
• Doll's eye reflex (oculocephalic reflex) and caloric testing in comatose patients
• Dysconjugate gaze = brainstem lesion

• Limb tone and power in all 4 limbs
• Asymmetric response to pain = focal brain injury / haematoma
• Decorticate posturing (abnormal flexion) - injury above red nucleus
• Decerebrate posturing (extension of all limbs) - midbrain/pontine injury (worse prognosis)
• Babinski sign (upgoing plantar) = upper motor neuron injury

• Check for gross sensory deficits

• Deep tendon reflexes
• Gag reflex, cough reflex (brainstem function)

• Ataxia, dysmetria (posterior fossa injury)

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Step 5: Important Associated Findings

• Impact seizures (immediate post-injury) - brief, with rapid return to normal; require CT but may be benign.
• Post-traumatic seizures suggest significant cortical injury.

• Retrograde amnesia = loss of memory for events before the injury
• Anterograde (post-traumatic) amnesia = loss of memory for events after the injury
• Duration of amnesia correlates with severity of brain injury

• Transient paraplegia or blindness following occipital/vertex blows
• Transient hemiparesis, aphasia or migrainous phenomena in athletes
• Delayed hemiplegia - consider expanding epidural/subdural haematoma or internal carotid dissection

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6. Special Patterns - Specific Injuries

Epidural Haematoma

• Classic lucid interval: brief LOC → apparent recovery → rapid deterioration
• Arterial bleeding (middle meningeal artery)
• Ipsilateral fixed dilated pupil + contralateral hemiparesis
• Usually temporal bone fracture

Subdural Haematoma

• Venous bleeding (bridging veins)
• Older patients at higher risk (brain atrophy increases tension on bridging veins)
• Acute: headache, confusion, declining GCS
• Chronic: gradual confusion, personality change, headache (can mimic dementia)

Subarachnoid Haematoma

• Sudden severe ("thunderclap") headache
• Meningism (neck stiffness, photophobia)

Diffuse Axonal Injury (DAI)

• High-speed rotational/deceleration forces
• Immediate coma without focal lesion on CT
• Common in MVAs
• Children particularly susceptible (less myelinated brain, higher water content)

Temporal Bone Fracture

• Longitudinal (80%): conductive hearing loss, CSF otorrhoea, external auditory canal fracture
• Transverse (20%): facial nerve palsy, sensorineural hearing loss (permanent), profound vertigo
• Bailey & Love's Surgery, p. 783

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7. Red Flag Features Requiring Urgent CT Head

• GCS < 15 at 2 hours post-injury
• Suspected open or depressed skull fracture
• Any sign of basal skull fracture (Battle's sign, raccoon eyes, CSF leak, haemotympanum)
• Two or more episodes of vomiting
• Age > 54 years

• Retrograde amnesia ≥ 30 minutes
• Dangerous mechanism (pedestrian/cyclist vs. vehicle; ejection from vehicle; fall > 3 feet/5 stairs)
• Adams & Victor's Principles of Neurology, 12th ed., p. 900

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8. Special Populations

Elderly (>60 years)

• Higher incidence of subdural and intraparenchymal haematomas
• Brain atrophy increases free space: significant bleeding may accumulate with minimal early symptoms
• Anticoagulant use (warfarin, clopidogrel, DOACs): warrants immediate non-contrast CT even with minor mechanism or no symptoms
• INR should be checked; degree of anticoagulation correlates with adverse outcome risk

Children

• Larger head-to-body ratio predisposes to higher torque forces
• Less myelinated brain: higher risk for shearing injury and DAI
• Sutures provide some protection but internal force can injure brain without skull fracture
• Modified (pediatric) GCS used for preverbal children

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Summary Table: Key Clinical Findings