362.1 🎓 醫孞生版

362.1.0.1 📌 䞀頁重點

362.1.0.1.1 Two-Step Diagnostic Approach

362.1.1 Step 1: Where? (Anatomic Localization)

  • Cortex: cognition, language, complex motor/sensory
  • Subcortical white matter: connectivity
  • Basal ganglia: movement (Parkinson, Huntington)
  • Brainstem: cranial nerves, consciousness, long tracts crossing
  • Cerebellum: coordination, balance, gait
  • Spinal cord: sensory level, UMN below, LMN at
  • Nerve root: dermatome/myotome
  • Plexus: multiple roots
  • Peripheral nerve: length-dependent (longest first)
  • NMJ: fatigable, fluctuating
  • Muscle: proximal weakness, CK elevated

362.1.2 Step 2: What? (Etiologic Diagnosis)

  • Vascular (sudden onset)
  • Inflammatory/Infectious (days-weeks)
  • Demyelinating
  • Neoplastic (progressive)
  • Degenerative (slow)
  • Traumatic
  • Metabolic/Toxic
  • Iatrogenic
  • Genetic
362.1.2.0.1 History

362.1.3 Key Elements

  • Onset (sudden = vascular; gradual = neoplastic, degenerative)
  • Duration + course (acute, subacute, chronic; static, progressive, fluctuating, relapsing-remitting)
  • Distribution (focal, multifocal, diffuse)
  • Associated symptoms (systemic, vascular risks)
  • Pre-existing conditions (DM, HTN, autoimmune, cancer)
  • Family history
  • Medications + substances
  • Functional impact

362.1.4 Time Course Clues

Pattern Suggests
Seconds-minutes Vascular (stroke), seizure
Hours-days Infection, inflammation
Weeks-months Tumor, autoimmune
Months-years Degenerative, hereditary
Fluctuating NMJ (MG), MS relapses
Stepwise Multi-infarct
362.1.4.0.1 Neurological Examination

362.1.5 Components

  1. Mental status: alertness, orientation, attention, memory, language, executive
  2. Cranial nerves: I-XII
  3. Motor: strength (0-5 MRC), tone, bulk, fasciculations
  4. Reflexes: DTRs, plantar (Babinski), primitive
  5. Sensation: light touch, pinprick, vibration, position, cortical
  6. Coordination: finger-nose, heel-shin, rapid alternating
  7. Gait + station: stance, tandem, Romberg
  8. Special tests: Hoffmann, Lhermitte, etc.

362.1.6 UMN vs LMN

Feature UMN LMN
Weakness Yes Yes
Tone ↑ (spasticity) ↓ (flaccid)
Atrophy Late Early, prominent
Reflexes ↑↑, clonus ↓ or absent
Fasciculations No Yes
Plantar Upgoing (Babinski) Downgoing

362.1.7 Glasgow Coma Scale (GCS)

  • Eye opening (1-4): spontaneous, to voice, to pain, none
  • Verbal (1-5): oriented, confused, inappropriate, incomprehensible, none
  • Motor (1-6): obeys, localizes, withdraws, flexor, extensor, none
  • Total 3-15
362.1.7.0.1 Neuroimaging

362.1.8 CT

  • Use: acute hemorrhage, trauma, bone
  • Fast, widely available
  • Limitations: posterior fossa, subtle lesions, early stroke

362.1.9 MRI

  • Definitive for most pathology
  • Sequences:
    • T1: anatomy, fat bright, fluid dark
    • T2: pathology bright (most), fluid bright
    • FLAIR: T2 with CSF suppressed; great for MS, edema
    • DWI: acute stroke (bright within minutes-hours)
    • **T2*/SWI**: hemosiderin, microbleeds
    • MRA/MRV: vessels
    • Gadolinium: enhancement (BBB disruption, tumor, infection, inflammation)

362.1.10 Other Imaging

  • CT/MR angiography: vessels
  • DSA (digital subtraction): gold standard for vessels
  • PET: FDG (metabolism), amyloid, tau, dopamine transporters
  • SPECT: perfusion
362.1.10.0.1 Electrophysiology

362.1.11 EEG

  • Seizures, encephalopathy, brain death
  • Generalized vs focal
  • Sleep stages

362.1.12 EMG + NCS

  • Neuropathy: axonal vs demyelinating
  • NMJ disorders: decremental response (MG), incremental (LEMS)
  • Myopathy: characteristic patterns

362.1.13 Evoked Potentials

  • VEP, BAEP, SSEP, MEP
  • MS demyelination
362.1.13.0.1 CSF Analysis (Lumbar Puncture)

362.1.14 Indications

  • Meningitis, encephalitis
  • SAH (CT-negative)
  • MS (oligoclonal bands)
  • Inflammatory/autoimmune
  • Cancer (LM disease)
  • Pressure (IIH, NPH)

362.1.15 Contraindications

  • ↑ ICP with mass effect (herniation risk)
  • Coagulopathy
  • Infection at puncture site

362.1.16 Components

  • Opening pressure (normal 10-20 cm H2O)
  • Cell count (normal < 5 WBC, no RBCs)
  • Protein (normal 15-45 mg/dL)
  • Glucose (normal 2/3 of serum)
  • Gram stain + culture
  • Specific: oligoclonal bands, cytology, flow, autoantibodies, PCR

362.1.17 Patterns

Condition Cell count Protein Glucose
Bacterial meningitis ↑↑ PMN ↑↑ ↓
Viral meningitis ↑ lymphs ↑ mild Normal
TB meningitis ↑ lymphs ↑↑ ↓
Fungal ↑ lymphs ↑ ↓
MS Mild ↑ lymph OCB Normal
SAH Many RBCs ↑ Normal
GBS Normal cells ↑↑ (albuminocytologic) Normal
362.1.17.0.1 Genetic Testing
  • Hereditary neuropathies
  • Muscular dystrophies
  • Movement disorders (Huntington, ataxias)
  • Mitochondrial diseases
  • Familial ALS
  • AD genetics (APP, PSEN1, PSEN2, APOE)

362.1.17.1 🩺 床邊速查

  • Localize first, then etiology
  • Onset speed → vascular (sudden), inflammatory (days), neoplastic (weeks-months), degenerative (months-years)
  • MRI > CT for most neuro pathology; CT for acute bleed
  • DWI: acute stroke (bright)
  • CSF patterns: bacterial (PMN, ↓ glucose), viral (lymphs, normal glucose), MS (OCB)
  • UMN vs LMN distinction critical