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Traumatic Head Injury | 마이메르시 MyMerci
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Traumatic Head Injury

NCLEX Review Guide: Head Injuries

Pathophysiology of Head Injuries

Primary vs. Secondary Brain Injury

  • Primary brain injury occurs at the moment of trauma and includes direct damage to brain tissue, blood vessels, and nerves. This includes contusions, lacerations, and diffuse axonal injury.
  • Secondary brain injury develops hours or days after the initial trauma as a result of cerebral edema, increased intracranial pressure (ICP), hypoxia, or ischemia.

Key Points

  • Primary injuries cannot be reversed; nursing care focuses on preventing secondary injuries.
  • Secondary injuries are potentially preventable with proper assessment and intervention.

Types of Head Injuries

  • Concussion: A temporary disruption of brain function without visible structural damage on standard imaging. Symptoms include confusion, amnesia, headache, and brief loss of consciousness.
  • Contusion: Bruising of brain tissue with bleeding and swelling. Can occur at the site of impact (coup) or on the opposite side of the brain (contrecoup).
  • Diffuse Axonal Injury (DAI): Widespread damage to axons caused by rotational forces, resulting in disruption of neural connections. Often causes prolonged unconsciousness and severe neurological deficits.
  • Epidural Hematoma: Arterial bleeding between the dura mater and skull, typically from a torn middle meningeal artery. Presents with brief loss of consciousness followed by a lucid interval, then rapid deterioration.
  • Subdural Hematoma: Venous bleeding between the dura and arachnoid layers. May be acute (symptoms within 48 hours), subacute (2-14 days), or chronic (>14 days).
  • Subarachnoid Hemorrhage: Bleeding into the subarachnoid space, causing severe headache, meningeal irritation, and potential vasospasm.

Comparison of Intracranial Hematomas

Feature Epidural Hematoma Subdural Hematoma
Source of bleeding Arterial (middle meningeal artery) Venous (bridging veins)
Onset Rapid (minutes to hours) Variable (hours to days)
Classic presentation Brief LOC → lucid interval → deterioration Gradual onset of symptoms, may be subtle in elderly
CT appearance Lens/biconvex shape Crescent shape
Common location Temporoparietal region Frontal and parietal regions

Key Points

  • The "lucid interval" is a hallmark sign of epidural hematoma and represents a medical emergency.
  • Elderly patients and those on anticoagulants are at higher risk for subdural hematomas, which may present with subtle symptoms.
  • DAI often has normal CT findings despite severe neurological impairment.

Assessment of Head Injuries

Neurological Assessment

  • The Glasgow Coma Scale (GCS) is the gold standard for assessing level of consciousness in head-injured patients. It evaluates eye opening (1-4 points), verbal response (1-5 points), and motor response (1-6 points), with a total score ranging from 3-15.
  • Pupillary assessment includes size, shape, equality, and reactivity to light. A unilateral dilated and nonreactive pupil may indicate increased ICP with herniation on the same side.
  • Vital signs should be monitored for Cushing's triad: hypertension, bradycardia, and irregular respirations - a late sign of increased ICP.
  • Motor function assessment includes strength, movement, and posturing. Decorticate (flexion) posturing indicates damage above the midbrain, while decerebrate (extension) posturing indicates damage at the midbrain/brainstem level.

Memory Aid: Glasgow Coma Scale

Remember "E-V-M" for the three components:

  • Eye opening (4 points max): 4 = Spontaneous, 3 = To voice, 2 = To pain, 1 = None
  • Verbal response (5 points max): 5 = Oriented, 4 = Confused, 3 = Inappropriate words, 2 = Incomprehensible sounds, 1 = None
  • Motor response (6 points max): 6 = Obeys commands, 5 = Localizes pain, 4 = Withdraws from pain, 3 = Flexion to pain, 2 = Extension to pain, 1 = None

Severity: 13-15 = Mild, 9-12 = Moderate, ≤8 = Severe (intubation often indicated)

Key Points

  • GCS ≤8 indicates severe head injury and likely need for airway protection.
  • Always document the specific components of the GCS, not just the total score.
  • Deteriorating GCS score is more significant than a single assessment.

Signs and Symptoms of Increased ICP

  • Early signs include headache, vomiting (especially projectile), altered level of consciousness, and subtle personality changes.
  • Late signs include Cushing's triad (hypertension, bradycardia, irregular respirations), pupillary changes, posturing, and respiratory pattern changes (Cheyne-Stokes, ataxic breathing).
  • Papilledema (swelling of the optic disc) may be present but develops over hours to days.

Clinical Scenario

A 24-year-old male is brought to the ED after a motorcycle accident. He was initially alert and oriented but now appears confused and has a severe headache. His right pupil is dilated and sluggishly reactive. Vital signs: BP 160/90, HR 58, RR 16 irregular. GCS is 13 (E3, V4, M6).

Analysis: This patient is showing signs of increased ICP with potential herniation. The deteriorating LOC, pupillary changes, and developing Cushing's triad (hypertension and bradycardia) require immediate intervention.

Key Points

  • Changes in neurological status, especially decreasing LOC, should be reported immediately.
  • Cushing's triad is a late sign of increased ICP and indicates impending herniation.
  • Pupillary changes often follow a predictable pattern with herniation: ipsilateral dilation → bilateral dilation.

Diagnostic Studies

  • CT scan is the initial diagnostic study of choice for acute head injury. It can quickly identify hemorrhage, fractures, edema, and mass effect.
  • MRI provides more detailed images and is better for identifying diffuse axonal injury, small contusions, and posterior fossa injuries, but is not typically used in the acute setting.
  • ICP monitoring may be used in severe head injuries (GCS ≤8) to guide treatment. Normal ICP is 5-15 mmHg; sustained values >20 mmHg require intervention.
  • Skull X-rays have limited value in acute head trauma and have largely been replaced by CT scans.

Key Points

  • CT scan without contrast is the gold standard for initial evaluation of acute head injury.
  • A normal CT scan does not rule out concussion or diffuse axonal injury.
  • Serial CT scans may be needed to monitor evolving injuries.

Management of Head Injuries

Initial Management

  1. Establish and maintain airway, breathing, and circulation (ABCs). Intubation may be needed for GCS ≤8 or deteriorating respiratory status.
  2. Immobilize the cervical spine until cleared (assume concurrent cervical injury in any patient with head trauma).
  3. Assess neurological status using GCS and pupillary response.
  4. Control external bleeding and address other life-threatening injuries.
  5. Obtain IV access and draw blood for laboratory studies.
  6. Administer isotonic fluids (normal saline) to maintain systolic BP >90 mmHg and prevent secondary brain injury from hypotension.
  7. Elevate head of bed 30° (if no spinal injury) to promote venous drainage and reduce ICP.
  8. Maintain normothermia and normoglycemia to prevent secondary brain injury.

Key Points

  • Hypotension (SBP <90 mmHg) and hypoxemia (PaO2 <60 mmHg) must be avoided as they significantly worsen outcomes.
  • Maintain euvolemia with isotonic fluids; avoid hypotonic solutions which may worsen cerebral edema.
  • Hyperventilation is no longer recommended as a routine measure for ICP control.

Management of Increased ICP

  • Positioning: Elevate head of bed 30° with head in neutral alignment to promote venous drainage. Avoid extreme hip flexion, which increases intra-abdominal pressure.
  • Osmotic therapy: Mannitol (0.25-1 g/kg IV) or hypertonic saline (3% or 7.5%) may be used to reduce cerebral edema by drawing fluid from brain tissue into the vascular space.
  • Sedation: Propofol, benzodiazepines, or barbiturates may be used to reduce cerebral metabolic demands and control agitation that can increase ICP.
  • CSF drainage: Ventricular drains may be placed to directly remove CSF and monitor ICP.
  • Surgical intervention: Craniotomy or craniectomy may be necessary to evacuate hematomas or create space for brain swelling.

Important Alert: Mannitol Administration

Before administering mannitol, ensure adequate intravascular volume and renal function. Monitor serum osmolality (keep <320 mOsm/L) and electrolytes. Rapid administration may cause hypotension and worsen cerebral perfusion. Use an in-line filter for administration.

Key Points

  • ICP >20-25 mmHg for >5 minutes typically requires intervention.
  • Cerebral perfusion pressure (CPP = MAP - ICP) should be maintained between 60-70 mmHg.
  • Avoid routine hyperventilation (PaCO2 <35 mmHg) as it can cause cerebral vasoconstriction and ischemia.

Nursing Care and Monitoring

  • Perform neurological assessments frequently (q1h or more often if unstable) and document trends.
  • Monitor vital signs, oxygen saturation, and end-tidal CO2 (if intubated).
  • Prevent factors that increase ICP: pain, anxiety, fever, seizures, coughing, Valsalva maneuver, and extreme neck rotation.
  • Maintain normothermia; treat fever aggressively as it increases cerebral metabolism and ICP.
  • Provide eye care for unconscious patients to prevent corneal abrasions.
  • Implement seizure precautions and administer prophylactic anticonvulsants as ordered.
  • Provide DVT prophylaxis (sequential compression devices and/or pharmacological prophylaxis as ordered).
  • Monitor fluid balance and electrolytes, especially sodium (both hyponatremia and hypernatremia can worsen cerebral edema).

Memory Aid: Factors That Increase ICP - "SCALP"

  • Straining (Valsalva maneuver)
  • Coughing/suctioning
  • Anxiety/agitation
  • Lying flat (position)
  • Pain/pyrexia (fever)

Key Points

  • Cluster nursing activities to minimize stimulation and allow rest periods.
  • Pre-medicate before potentially noxious stimuli (e.g., suctioning).
  • Maintain strict glycemic control as both hypoglycemia and hyperglycemia can worsen outcomes.

Special Considerations

Concussion Management

  • Concussions may not appear on standard imaging but can cause significant symptoms and functional impairment.
  • Symptoms include headache, dizziness, nausea, fatigue, sleep disturbances, and cognitive issues (memory problems, difficulty concentrating).
  • Physical and cognitive rest is recommended during the acute phase (24-48 hours), followed by gradual return to activities.
  • Provide patient education on post-concussive symptoms, expected recovery timeline, and when to seek medical attention.

Return to Activity Protocol After Concussion

Stage Activity Level Examples
1 No activity Complete physical and cognitive rest
2 Light aerobic exercise Walking, swimming, stationary cycling at <70% max heart rate
3 Sport-specific exercise Running drills, no head impact activities
4 Non-contact training More complex training drills, progressive resistance training
5 Full contact practice Following medical clearance
6 Return to normal activity Normal game play or activity

Key Points

  • Each stage of return to activity should take at least 24 hours; if symptoms return, the patient should rest and try again when symptoms resolve.
  • Second impact syndrome, although rare, can be catastrophic if a second concussion occurs before the first has resolved.
  • Long-term effects of multiple concussions include chronic traumatic encephalopathy (CTE).

Pediatric Considerations

  • Children have different physiological responses to head trauma compared to adults. Their higher brain water content and larger head-to-body ratio increase vulnerability.
  • The pediatric GCS includes modifications for verbal responses in pre-verbal children.
  • Children may have normal neurological exams despite significant intracranial injury ("talk and die" syndrome).
  • Signs of increased ICP in infants include bulging fontanelles, separated sutures, irritability, high-pitched cry, and setting-sun sign (downward deviation of eyes).

Important Alert: Pediatric Vital Signs

Cushing's triad manifests differently in children. Bradycardia is an ominous sign in pediatric patients and indicates severe, life-threatening increased ICP. Children can maintain normal blood pressure until late stages of decompensation, then rapidly deteriorate.

Key Points

  • The absence of loss of consciousness does not rule out significant head injury in children.
  • Child abuse should be considered in infants and young children with head injuries, especially if the history is inconsistent with the injury pattern.
  • Radiation exposure from CT scans is a greater concern in children; clinical decision rules help determine when imaging is necessary.

Geriatric Considerations

  • Elderly patients are at higher risk for head injuries due to falls and have worse outcomes compared to younger patients with similar injuries.
  • Brain atrophy provides more space for blood collection before symptoms appear, potentially masking significant subdural hematomas.
  • Anticoagulant and antiplatelet medications increase the risk of intracranial hemorrhage, even after minor trauma.
  • Baseline cognitive impairment can make neurological assessment challenging; obtain history from family members or caregivers about baseline function.

Key Points

  • Have a lower threshold for obtaining CT scans in elderly patients, especially those on anticoagulants.
  • Chronic subdural hematomas may present with subtle symptoms like mild confusion, personality changes, or gait disturbances.
  • Fall risk assessment and prevention strategies are essential components of discharge planning.

Commonly Confused Concepts

Concussion vs. Contusion

Feature Concussion Contusion
Definition Functional brain injury without visible structural damage Bruising of brain tissue with visible hemorrhage
Imaging findings Usually normal on CT/MRI Visible areas of hemorrhage and edema
Duration of symptoms Usually resolves in days to weeks May cause permanent deficits
Management Rest, symptom management, gradual return to activities May require surgical intervention, ICP management

Key Points

  • Concussions are functional injuries that typically don't show on imaging but can cause significant symptoms.
  • Contusions involve actual bruising of brain tissue and are visible on CT or MRI.

Decorticate vs. Decerebrate Posturing

Feature Decorticate Posturing Decerebrate Posturing
Position Flexion of arms, wrists, and fingers; extension of legs Extension and pronation of arms; extension of legs
Level of injury Cerebral cortex/internal capsule (above midbrain) Midbrain/upper brainstem
Severity Less severe More severe
Memory aid "DeCorticate = Flex toward Core" "DeCerebrate = Extended away from Cerebrum"

Key Points

  • Progression from decorticate to decerebrate posturing indicates deterioration.
  • Both types of posturing indicate severe brain injury and require immediate intervention.

Herniation Syndromes

  • Uncal herniation: Displacement of the uncus of the temporal lobe through the tentorial notch, compressing the oculomotor nerve (CN III) and cerebral peduncle. Classic signs include ipsilateral pupillary dilation and contralateral hemiparesis.
  • Central herniation: Downward displacement of the diencephalon and midbrain through the tentorial notch. Signs progress from small, reactive pupils to fixed, midposition pupils, followed by respiratory abnormalities.
  • Tonsillar herniation: Displacement of the cerebellar tonsils through the foramen magnum, compressing the medulla. Signs include neck rigidity, respiratory and cardiac irregularities, and rapid loss of consciousness.

Important Alert: Herniation Recognition

Herniation syndromes represent neurosurgical emergencies requiring immediate intervention. Key warning signs include: unilateral pupillary dilation, decreasing level of consciousness, new or worsening motor deficits, Cushing's triad, and irregular respiratory patterns.

Key Points

  • Uncal herniation typically presents with a "blown pupil" on the same side as the lesion.
  • Tonsillar herniation is rapidly fatal if not promptly treated.
  • Emergency interventions include hyperventilation, osmotic therapy, and surgical decompression.

Study Tips and Memory Aids

Key Nursing Interventions

Memory Aid: "BRAIN" for Head Injury Care

  • Bed position - Elevate HOB 30°, maintain neutral alignment
  • Respiratory support - Maintain PaO2 >80 mmHg, prevent hypercapnia
  • Assessment - Frequent neurological checks, monitor for increased ICP
  • Intracranial pressure - Avoid factors that increase ICP, administer medications as ordered
  • Normalize - Maintain normal temperature, glucose, electrolytes, and volume status

Key Points

  • Preventing secondary brain injury is the primary goal of nursing care.
  • Serial assessments are more valuable than single measurements.

Common NCLEX Questions on Head Injuries

  • NCLEX often tests prioritization of care for patients with head injuries.
  • Expect questions on recognition of increased ICP and appropriate interventions.
  • Questions may focus on differentiating types of head injuries based on assessment findings.
  • Know the nursing care for patients with ICP monitoring devices.
  • Understand medication administration principles for mannitol, hypertonic saline, and anticonvulsants.

Quick Check

A patient with a head injury develops a dilated right pupil, left-sided weakness, and decreasing level of consciousness. What is the priority nursing action?

Answer: Notify the provider immediately as these are signs of uncal herniation, a neurosurgical emergency.

Key Points

  • Focus on assessment, recognition of complications, and prioritization of care.
  • Remember that the ABCs always come first, even with neurological emergencies.

Common Pitfalls to Avoid

  • Pitfall #1: Focusing only on the GCS total score without consi

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