Neurology System Study Guide

Neurological Assessment

Level of Consciousness

• Glasgow Coma Scale (GCS): Eye (4), Verbal (5), Motor (6) = Total 3-15
• GCS ≤8: Generally indicates need for airway protection
• Assess for changes from baseline - trends matter
• AVPU: Alert, Verbal response, Pain response, Unresponsive

Pupil Assessment

• PERRLA: Pupils Equal, Round, Reactive to Light, Accommodation
• Fixed dilated pupil: Suggests ipsilateral herniation or CN III compression
• Bilateral fixed dilated: Brain death, severe anoxia, drug effect
• Pinpoint pupils: Opioid overdose, pontine lesion
• Document size in millimeters, shape, and reactivity

Motor Assessment

• Assess all four extremities for strength (0-5 scale)
• Pronator drift: Early sign of upper motor neuron weakness
• Decorticate posturing: Flexion of arms (cortical damage)
• Decerebrate posturing: Extension of arms (brainstem damage)
• Flaccid: No motor response (severe brainstem injury or spinal cord)

Cranial Nerve Assessment

• CN II: Vision, pupil response
• CN III, IV, VI: Eye movements (test with H pattern)
• CN V: Facial sensation, corneal reflex
• CN VII: Facial movement symmetry
• CN IX, X: Gag reflex, swallow (important for aspiration risk)
• CN XII: Tongue movement, deviation toward weak side

Stroke Management

Ischemic vs Hemorrhagic Stroke

• Ischemic (87%): Thrombotic or embolic occlusion of cerebral vessel
• Hemorrhagic (13%): Intracerebral hemorrhage or subarachnoid hemorrhage
• CT scan WITHOUT contrast to differentiate (blood appears white)
• Treatment differs drastically - must differentiate before intervention

NIHSS Scoring

• National Institutes of Health Stroke Scale
• 0: No stroke symptoms
• 1-4: Minor stroke
• 5-15: Moderate stroke
• 16-20: Moderate to severe stroke
• 21-42: Severe stroke
• Higher scores indicate greater neurological deficit
• Used to guide treatment decisions and predict outcomes

Ischemic Stroke Treatment

• IV tPA (Alteplase): Within 4.5 hours of symptom onset
• Strict BP control: <185/110 before tPA, <180/105 after tPA
• Mechanical thrombectomy: Up to 24 hours for large vessel occlusion
• Aspirin: 24-48 hours after ruling out hemorrhage
• Permissive hypertension initially (allows collateral flow)
• Monitor for hemorrhagic transformation post-tPA

tPA Contraindications

• Active internal bleeding or bleeding diathesis
• Recent major surgery or trauma (<14 days)
• History of intracranial hemorrhage
• Uncontrolled hypertension (>185/110)
• Platelet count <100,000
• INR >1.7 or current anticoagulation
• Recent stroke or head trauma (<3 months)

Hemorrhagic Stroke Management

• NO tPA - would worsen bleeding
• Reverse anticoagulation if applicable
• BP control: Target SBP <140 mmHg
• Neurosurgical consult for possible evacuation
• Monitor for hydrocephalus - may need EVD
• Seizure prophylaxis consideration

Increased Intracranial Pressure

ICP Fundamentals

• Normal ICP: 5-15 mmHg
• Cerebral Perfusion Pressure (CPP) = MAP - ICP
• Goal CPP: 60-70 mmHg (maintain cerebral blood flow)
• Monro-Kellie Doctrine: Skull is fixed - brain, blood, CSF must balance
• Increased volume of one component → increased ICP

Signs of Increased ICP

• Cushing Triad: Hypertension, Bradycardia, Irregular respirations (LATE sign)
• Decreased LOC, confusion, lethargy
• Headache (often worse in morning)
• Nausea/vomiting (often projectile)
• Pupil changes: Unilateral dilation, sluggish response
• Papilledema on fundoscopic exam

ICP Management Strategies

• Head of bed 30 degrees, head midline
• Avoid neck flexion, tight cervical collars
• Maintain normothermia (fever increases metabolic demand)
• Sedation and analgesia to reduce agitation
• Avoid hypotension, hypoxia, hypercapnia
• Target PaCO2 35-40 mmHg (avoid hyperventilation unless herniation)

Medical Treatment of Elevated ICP

• Osmotic therapy: Mannitol 20% (0.25-1 g/kg IV)
• Hypertonic saline: 3% or 23.4% (monitor sodium)
• CSF drainage via EVD if in place
• Hyperventilation: Only for acute herniation (temporary)
• Barbiturate coma: Last resort, decreases metabolic demand
• Decompressive craniectomy for refractory elevation

Brain Herniation Syndromes

• Uncal herniation: Ipsilateral pupil dilation, contralateral weakness
• Central herniation: Bilateral pupil changes, decerebrate posturing
• Tonsillar herniation: Brainstem compression, respiratory arrest
• Time-critical emergency - requires immediate intervention

Seizures & Status Epilepticus

Seizure Types

• Generalized tonic-clonic: Full body stiffening then rhythmic jerking
• Absence: Brief staring episodes (petit mal)
• Focal (partial): Limited to one area, may spread
• Myoclonic: Brief muscle jerks
• Atonic: Sudden loss of muscle tone (drop attacks)

Status Epilepticus

• Definition: Seizure lasting >5 minutes OR multiple seizures without return to baseline
• Medical emergency - can cause permanent brain damage
• Causes: Non-compliance with AEDs, alcohol withdrawal, infection, electrolyte imbalance
• Mortality increases with duration of seizure activity

Status Epilepticus Treatment

• ABCs: Protect airway, supplemental oxygen
• First-line: Benzodiazepines (Lorazepam 4mg IV or Midazolam IM)
• Second-line: Fosphenytoin, Valproate, or Levetiracetam
• Refractory: Propofol, Midazolam infusion, or Pentobarbital
• Check glucose - treat hypoglycemia
• Continuous EEG monitoring if intubated

Post-Seizure Care

• Monitor for recurrence
• Maintain seizure precautions: Padded side rails, suction available
• Document: Duration, type of movement, post-ictal state
• Check AED levels if applicable
• Identify and treat underlying cause

Traumatic Brain Injury

TBI Classification

• Mild TBI (Concussion): GCS 13-15
• Moderate TBI: GCS 9-12
• Severe TBI: GCS 3-8
• Primary injury: Direct damage at time of trauma
• Secondary injury: Subsequent damage from hypoxia, hypotension, edema

Types of Intracranial Hemorrhage

• Epidural hematoma: Between skull and dura, often arterial (lucid interval)
• Subdural hematoma: Between dura and arachnoid, venous bleeding
• Subarachnoid hemorrhage: In subarachnoid space, often aneurysm rupture
• Intracerebral hemorrhage: Within brain parenchyma
• Contusion: Bruising of brain tissue

TBI Management Goals

• Prevent secondary injury: Avoid hypotension and hypoxia
• SBP goal: >100 mmHg (age 50-69), >110 mmHg (age 15-49 or >70)
• PaO2 >60 mmHg, SpO2 >90%
• ICP monitoring for severe TBI (GCS ≤8 with abnormal CT)
• Maintain CPP 60-70 mmHg
• Seizure prophylaxis for first 7 days

Nursing Considerations

• Frequent neuro checks (GCS, pupils, motor)
• Head of bed elevated, head midline
• Prevent increases in ICP: Avoid Valsalva, clustering care
• Temperature management: Avoid hyperthermia
• Prevent complications: DVT prophylaxis when safe, stress ulcer prophylaxis

Brain Death Assessment

Brain Death Definition

• Irreversible cessation of all brain function including brainstem
• Legal definition of death in most jurisdictions
• Must rule out confounders: Hypothermia, drug effects, severe metabolic derangement
• Core temperature must be >36°C before testing

Clinical Examination Criteria

• Coma: No eye opening or motor response to painful stimuli
• Absent brainstem reflexes: Pupillary, corneal, oculocephalic, oculovestibular
• Absent gag and cough reflexes
• No respiratory drive (apnea test)
• Two examinations typically required, separated by observation period

Apnea Test

• Pre-oxygenate with 100% FiO2 for 10 minutes
• Disconnect from ventilator, provide passive oxygen
• Observe for respiratory effort for 8-10 minutes
• Target PaCO2 >60 mmHg (or 20 mmHg above baseline)
• Positive test: No respiratory effort with adequate CO2 stimulus
• Abort if hemodynamic instability or desaturation

Confirmatory Testing

• May be needed if clinical exam cannot be completed
• Cerebral angiography: No intracranial blood flow
• Nuclear medicine brain scan: No uptake
• EEG: Electrocerebral silence
• Transcranial Doppler: Absent diastolic or reverberating flow

Nursing Considerations

• Support family through process
• Consider organ donation - contact OPO early
• Document all examination findings carefully
• Maintain physiological support until family decision and organ recovery
• Time of death is time of brain death declaration