Nervous System

Craniosynostosis

Type	Premature Suture
Trigonocephaly	Metopic
Scaphocephaly [Dolichocephaly]	Sagittal
Brachycephaly	Coronal
Plagiocephaly :: anterior	Unilateral coronal
Plagiocephaly :: posterior	Unilateral lambdoid

Indications for CT Imaging for Head Trauma

PECARN Rule

• GCS < 15
• Altered mental status
• Suspected skull fracture
• Non-frontal scalp hematoma
• LOC > 5 seconds
• Vomiting
• Headache
• Dangerous mechanism

Canadian CT Head Rule

• GCS < 15 at 2 hours after injury
• Suspected skull fracture
• Vomiting ≥ 2 episodes
• Age > 65 years
• Retrograde amnesia
• Dangerous mechanism

Signs of Basilar Skull Fracture

• Racoon eyes
• Battle sign
• CSF otorrhea
• CSF rhinorrhea
• Hemotympanum

Cortical Signs

Lobe	Area	Signs
Frontal	Prefrontal cortex	Personality changes
	Frontal eye fields (FEF)	Ipsilateral conjugate deviation
	Broca area :: dominant	Broca aphasia
	Motor cortex	Contralateral paralysis
Parietal	Sensory cortex	Contralateral paresthesia
	Arcuate fasciculus :: dominant	Conduction aphasia
	Association cortex :: dominant	Gerstmann syndrome: Acalculia Agraphia Finger agnosia
	Association cortex :: nondominant	Contralateral hemineglect Constructional apraxia Dressing apraxia
	Superior optic radiation	Contralateral inferior quadrantanopia
Temporal	Wernicke area :: dominant	Wernicke aphasia
	Meyer loop	Contralateral superior quadrantanopia
Occipital	Visual cortex	Contralateral hemianopia

Hemorrhage

Extracranial

Hemorrhage	Vessels	Bounded
Caput succedaneum	Soft tissues	-
Subgaleal	Subgaleal vessels	-
Cephalohematoma	Subperiosteal vessels	+

Intracranial

Hemorrhage	Vessels	Bounded
Epidural	Middle meningeal artery	+
Subdural	Bridging veins	-
Subarachnoid	Aneurysm Arteriovenous malformation (AVM)	-
Intraparenchymal	Microaneurysm Lipohyalinosis Amyloid angiopathy	-

Risk of Progression of TIA to Ischemic Stroke {ABCD2}

• Age > 60 years
• BP > 140/90 mmHg
• Clinical features
  • Unilateral weakness
  • Speech impairment
• Duration
• Diabetes

Presentation of Ischemic Stroke

Artery	Lesions	Symptoms
Middle cerebral artery (MCA)	Motor cortex :: upper Sensory cortex :: upper Wernicke area Broca area Frontal eye fields (FEF)	Contralateral facial palsy Contralateral paralysis Contralateral paresthesia Aphasia Hemineglect
Anterior cerebral artery (ACA)	Motor cortex :: lower Sensory cortex :: lower	Contralateral paralysis Contralateral paresthesia
Posterior cerebral artery (PCA)	Occipital lobe	Contralateral hemianopia
Lenticulo-striate artery	Internal capsule Striatum	Contralateral paralysis
Basilar artery	CN VI Paramedian pontine reticular formation (PPRF) Corticobulbar tract Corticospinal tract	Locked-in syndrome Medial pontine syndrome: Horizontal gaze palsy Pseudobulbar palsy Contralateral paralysis
Anterior inferior cerebellar artery (AICA)	CN VII & CN VIII Sympathetic fibers Cerebellar peduncles	Lateral pontine syndrome: Ipsilateral facial palsy Ipsilateral deafness Ipsilateral vertigo Ipsilateral Horner syndrome Ipsilateral ataxia
Posterior inferior cerebellar artery (PICA)	Ambiguous nucleus Sympathetic fibers Cerebellar peduncle Lateral spinothalamic tract	Lateral medullary [Wallenberg] syndrome: Dysphagia Dysarthria ↓ Gag reflex Contralateral palate deviation Ipsilateral Horner syndrome Ipsilateral ataxia Contralateral paresthesia
Anterior spinal artery (ASA)	CN XII Corticospinal tract Medial lemniscus	Medial medullary syndrome: Ipsilateral tongue deviation Contralateral paralysis Contralateral paresthesia

Workup of Ischemic Stroke

• Coagulation panel
• Non-contrast CT of the head
• CT angiography of the head and neck
• MR imaging of the head
• Carotid ultrasound
• Electrocardiography (ECG)
• Echocardiography

Treatment of Ischemic Stroke

• Antihypertensives
  • BP < 185/110 mmHg if revascularization
  • BP < 220/120 mmHg otherwise
• Antihyperglycemic if glucose > 140 ~ 180 mg/dL
• Antiplatelets
• Revascularization
  • Thrombolysis if duration < 3 ~ 4.5 hours
  • Thrombectomy if duration < 6 ~ 24 hours

Ideal Door-to-Reperfusion Time for Ischemic Stroke

• Door-to-needle < 60 minutes
• Door-to-puncture < 120 minutes

Brain Lesions & Breathing Patterns

Brain Lesion	Breathing Pattern
Cerebrum	Cheyne-Stokes respiration
Midbrain	Tachypnea
Upper pons	Apneustic respiration
Lower pons	Cluster respiration
Medulla	Ataxic [Biot] respiration

Abnormal Neurologic Examination Findings in Hemineglect

• Cancellation test
• Reading test
• Bisection of lines
• Copy of drawings

Aphasia

Aphasia	Comprehension	Repetition	Fluency
Global	↓	↓	↓
Broca	-	↓	↓
Wernicke	↓	↓	-
Conduction	-	↓	-
Mixed transcortical	↓	-	↓
Transcortical motor	-	-	↓
Transcortical sensory	↓	-	-

Triad of Normal Pressure Hydrocephalus (NPH) {3W}

Mnemonic	Presentation
Wet	Urinary incontinence
Wobbly	Ataxia
Wacky	Cognitive dysfunction

Presentation of Elevated Intracranial Pressure (ICP)

• Cushing triad
  • Pressure :: hypertension & ↑ pulse pressure
  • Pulse :: bradycardia
  • Respiration :: pattern change
• ↓ Consciousness
• Headache
• Nausea ± vomiting
• Papilledema
• Diplopia

Treatment of Elevated Intracranial Pressure (ICP)

• Position :: head elevation
• Hyperventilation
• Diuretics :: Mannitol
• Sedation
• Corticosteroids
• Craniectomy

Treatment of Idiopathic Intracranial Hypertension (IIH)

• Weight loss
• Diuretics
  • Acetazolemide
  • Loop diuretics
• Topiramate
• Lumbar puncture
• Shunting
• Optic nerve sheath fenestration

Contraindications to Lumbar Puncture

• Skin infection over puncture site
• Brain mass causing ↑ intracranial pressure (ICP)

Types of Primary Headaches

	Cluster	Migraine	Tension
Sex	Male	Female	-
Laterality	Unilateral	Unilateral	Bilateral
Location	Periorbital	Head	Band
Duration	15 minutes ~ 3 hours	4 hours ~ 3 days	30 minutes ~ 7 days
Triggers	-	+	+

Treatment of Primary Headaches

Headache	Acute	Chronic
Cluster	100% O2 -Triptans	Verapamil
Migraine	NSAIDs -Triptans Ergotamine	β antagonists TCAs Valproate Topiramate Botulinum toxin Lifestyle modification
Tension	NSAIDs Acetaminophen	TCAs Lifestyle modification

Red Flags for Secondary Headaches

• Sudden onset
• Onset after 50 y/o
• ↑ frequency or severity
• New onset with an underlying medical condition
• Focal neurologic sequelae
• Papilledema
• Preceding head trauma

Seizures

Anticonvulsants

Mechanism	Medication
Na channel blockers	Phenytoin Valproate Carbamazepine Lamotrigine Topiramate
Ca channel blockers	Ethosuximide Gabapentin Pregabalin
SV2A antagonists	Levetiracetam
GABAA agonists	Barbiturates Benzodiazepines
GABA reuptake inhibitors	Tiagabine
GABA transaminase inhibitors	Vigabatrin

Treatment of Status Epilepticus

• Barbiturates
• Benzodiazepines
• Phenytoin

Treatment of Neuropathic Pain

• Ca channel blockers
  • Gabapentin
  • Pregabalin
• Reuptake inhibitors
  • TCAs
  • SNRIs

Treatment of Essential Tremor

• β antagonists :: Propranolol
• Barbiturates :: Primidone

Neurodegenerative Disorders

Disorder	Lesions	Findings	Precursor
Parkinson disease	Substantia nigra	Lewy body	α-Synuclein
Huntington disease	Striatum	-	-
Alzheimer disease	Cortex Hippocampus	Senile plaque	Amyloid precursor protein (APP)
		Neurofibrillary tangle	Tau protein
		Hirano body	Actin
Frontotemporal dementia	Frontotemporal lobe	Pick body	Tau protein
Lewy body dementia	Cortex	Lewy body	α-Synuclein
Vascular dementia	Cortex	-	-
Normal pressure hydrocephalus (NPH)	-	-	-
Creutzfeldt-Jakob disease	Striatum	Prion	Prion protein (PrP)

Basal Ganglia and Diseases

Presentation of Parkinson Disease {PARTS}

• Postural instability
• Akinesia & Bradykinesia
• Rigidity :: cogwheel
• Tremor :: resting & pill-rolling
• Shuffling gait

Medications for Parkinson Disease

Mechanism	Medication
M antagonists	Benztropine
D2 agonists	Bromocriptine Cabergoline Pramipexole Ropinirole
MAO inhibitors	Selegiline
COMT inhibitors	-Capones
Dopa	Levodopa
Dopa decarboxylase inhibitors	Carbidopa Benserazide
NMDA antagonists	Amantadine

Treatment of Restless Legs Syndrome (RLS)

• Ca channel blockers
  • Gabapentin
  • Pregabalin
• Levodopa
• D₂ agonists
  • Pramipexole
  • Ropinirole

Medications for Huntington Disease

Mechanism	Medication
VMAT2 inhibitors	Tetrabenazine Valbenazine
D2 antagonists	2° Antipsychotics

Medications for Alzheimer Disease

Mechanism	Medication
ACh esterase inhibitors	Rivastigmine Galantamine Donepezil
NMDA antagonists	Memantine

Etiology of Myelopathy

Lesion	Dorsal Column	Spinothalamic Tract	Corticospinal Tract	Anterior Horn
Syringomyelia	-	-	-	-
Poliomyelitis	-	-	-	+
Spinal muscular atrophy (SMA)	-	-	-	+
Amyotrophic lateral sclerosis (ALS)	-	-	+	+
Tabes dorsalis	+	-	-	-
Subacute combined degeneration (SCD)	+	-	+	-
Anterior spinal artery syndrome	-	+	+	+
Brown-Sequard syndrome	+	+	+	+
Transverse myelopathy	+	+	+	+

Etiology of Peripheral Neuropathy

• Heme synthesis disorders
• Diabetic neuropathy
• Chemotherapy toxicity
• Tabes dorsalis
• Subacute combined degeneration (SCD)
• Guillain-Barre syndrome (GBS)
• Charcot-Marie-Tooth (CMT) disease

Demyelinating Diseases

• Central pontine myelinolysis (CPM)
• Multiple sclerosis
• Progressive multifocal leukoencephalopathy (PML)
• Leukodystrophies
• Tabes dorsalis
• Subacute combined degeneration (SCD)
• Guillain-Barre syndrome (GBS)
• Charcot-Marie-Tooth (CMT) disease

Charcot Triad of Multiple Sclerosis {SIN}

• Scanning speech
• Intention tremor
• Incontinence
• Internuclear ophthalmoplegia
• Nystagmus

White Matters Affected By Multiple Sclerosis

White Matter	Symptoms
Optic nerve	Marcus Gunn pupil
Medial longitudinal fasciculus (MLF)	Internuclear ophthalmoplegia Nystagmus
Cerebellum	Scanning speech Intention tremor
Spinal cord	Incontinence

Types of Multiple Sclerosis

• Relapsing-remitting
• Progressive relapsing
• 1° progressive
• 2° progressive

Treatment of Multiple Sclerosis

Mechanism	Medication
NF-κB inhibitors	Corticosteroids
CD20 inhibitors	Ocrelizumab
CD52 inhibitors	Alemtuzumab
α4-integrin inhibitors	Natalizumab
-	Plasmapheresis
-	IFN-β

Treatment of Guillain-Barre Syndrome (GBS)

• Plasmapheresis
• Intravenous immunoglobulin (IVIG)

Comparison Between UMN and LMN Lesions

	UMN	LMN
Weakness	+	+
Atrophy	-	+
Fasciculations	-	+
Tone	↑	↓
Reflexes	↑	↓
Primitive reflexes	+	-
Paralysis	Spastic	Flaccid

• Upper motor neuron (UMN)
• Lower motor neuron (LMN)

Abnormal Physical Examination Findings in Nerve Injuries

Exam	Injury
Lhermitte sign	Cervical myelopathy
Spurling test	Cervical radiculopathy
Kemp test	Lumbar radiculopathy
Straight leg raising test (SLRT)	Lumbar radiculopathy
Hoffmann sign	UMN lesion
Babinski sign	UMN lesion

Evoked Electromyography (EMG)

Interpretation of Electromyograghy (EMG)

Condition	Rest	Amplitude	Duration	Phase	Recruitment
Normal	-	0.2 ~ 2 mV	5 ~ 15 ms	Triphasic	-
Neuropathy :: UMN	-	-	-	Triphasic	-
Neuropathy :: LMN	Fibrillations	↑	↑	Polyphasic	↓
Myopathy :: non-inflammatory	-	↓	↓	Polyphasic	↑
Myopathy :: inflammatory	Fibrillations	↓	↓	Polyphasic	↑

Etiology of Myopathy

• Inflammatory myopathy
  • Polymyositis
  • Dermatomyositis
• Endocrine
  • Hypothyroidism
  • Cushing syndrome
• Metabolic myopathy
  • Glycogen storage diseases (GSD)
  • Lysosomal storage diseases (LSD)
• Muscular dystrophy
  • Duchenne muscular dystrophy (DMD)
  • Myotonic dystrophy
  • Limb-girdle muscular dystrophy
• Drug-induced myopathy
• Rhabdomyolysis

Comparison Between Myopathy and Myalgia

	Myopathy	PMR	Fibromyalgia
ESR	↑/-	↑	-
CK	↑	-	-

Pathogenesis of Horner Syndrome

Etiology of Horner Syndrome

• Ischemic stroke
  • Anterior inferior cerebellar artery (AICA)
  • Posterior inferior cerebellar artery (PICA)
• Pancoast tumor
• Carotid dissection

Presentation of Horner Syndrome {MAP}

• Miosis
• Anhidrosis
• Ptosis :: superior tarsal muscle

Etiology of Neurogenic Bladder

• Stroke
• Normal pressure hydrocephalus (NPH)
• Multiple sclerosis
• Neurodegenerative disorders
• Cauda equina syndrome
• Herniated disk
• Spinal cord injury
• Spinal stenosis
• Diabetic neuropathy

CSF Analysis

	Pressure	WBCs	Glucose	Protein
Normal	50 ~ 180 mmH2O	< 5/mm3	40 ~ 70 mg/dL	20 ~ 45 mg/dL
Inflammatory	-	-	-	↑
Bacterial	↑	↑ PMNs	↓	↑
TB & Fungal	↑	↑ Lymphocytes	↓	↑
Viral	↑	↑ Lymphocytes	-	↑

IgG Index

Parameter	(CSFIgG ÷ CSFAlbumin) ÷ (PIgG ÷ PAlbumin)
CSFIgG	CSF IgG
CSFAlbumin	CSF albumin
PIgG	Serum IgG
PAlbumin	Serum albumin

Routes of Brain Abscess Transmission

• Hematogenous spread
• Direct spread
  • Paranasal sinusitis
  • Otitis media
  • Mastoiditis
  • Dental infection
• Direct innoculation

Pathogens of Encephalitis

• Arbovirus
• Enterovirus
• HSV
• VZV
• CMV
• Toxoplasmosis
• Malaria

Pathogens of Meningitis

• Streptococcus pneumonia
• Haemophilus influenzae
• Neisseria meningitidis
• Enterovirus
• HSV & HIV
• Cryptococcus

Empirical Antibiotics for Meningitis

Patient	Antibiotics
≤ 1 month	Ampicillin & (3° Cephalosporins / Aminoglycosides)
1 ~ 3 months	Vancomycin & 3° Cephalosporins
3 months ~ 60 years	Vancomycin & 3° Cephalosporins
≥ 60 years Complicated	Vancomycin & Ampicillin & 3° Cephalosporins

Nervous System Tumors

Central Nervous System (CNS) Tumors

Cell	Origin	Tumors
Neurons	Neural tube	Neuroblastoma
Astrocytes	Neural tube	Astrocytoma
Ependymal cells	Neural tube	Ependymoma
Oligodendrocytes	Neural tube	Oligodendroglioma
Neuroendocrine cells	Neural tube	Pinealoma
Neuroendocrine cells	Surface ectoderm	Craniopharyngioma Pituitary adenoma
Meninges	Neural crest	Meningioma
Microglia	Mesoderm	-

Peripheral Nervous System (PNS) Tumors

Cell	Origin	Tumors
Neurons	Neural crest	Neuroblastoma
Schwann cells	Neural crest	Schwannoma
Neuroendocrine cells	Neural crest	Pheochromocytoma Paraganglioma

WHO Grading of Astrocytoma

Grade	Tumor
1	Pilocytic astrocytoma
2	Fibrillary astrocytoma
3	Anaplastic astrocytoma
4	Glioblastoma multiforme

Neural Crest Tumors

• Neuroblastoma
• Pheochromocytoma
• Paraganglioma
• Schwannoma
• Neurofibroma
• Melanoma

Management of Pituitary Adenoma

Condition	Management
Prolactinoma	Pharmacotherapy
Non-PRL secretory	Surgery
Non-secretory	Surgery
Asymptomatic	Observation

Disorders of Consciousness

	Awareness	SWC	BR	SR
Brain death	-	-	-	-
Coma	-	-	+	+
Vegetative state	-	+	+	+
Minimally conscious state	±	+	+	+
Locked-in syndrome	+	+	+	+

• Sleep-wake cycle (SWC)
• Brainstem reflex (BR)
• Spontaneous respiration (SR)

Neurologic Examination for Brain Death

• Posturing
• Pupillary reflex
• Corneal reflex
• Vestibulo-ocular reflex
• Gag reflex
• Cough reflex

Indications for Polysomnography

• Sleep apnea
• Sleep-wake disorders

Triad of Anesthesia

• Hypnosis
• Analgesia
• Muscle relaxation

Medications for General Anesthesia

Mechanism	Medication	Indications
GABAA agonists	Barbiturate	Anesthesia :: intravenous
	Benzodiazepine	Anesthesia :: intravenous
	Propofol	Anesthesia :: intravenous
	Etomidate	Anesthesia :: intravenous
NMDA antagonists	Ketamine	Anesthesia :: intravenous
↓ CNS	Nitrous oxide (N2O)	Anesthesia :: inhalational
	Halothane	Anesthesia :: inhalational
	Desflurane	Anesthesia :: inhalational
	Enflurane	Anesthesia :: inhalational
	Isoflurane	Anesthesia :: inhalational
	Sevoflurane	Anesthesia :: inhalational

Contraindications to Neuraxial Blockade {CHIPS}

• Coagulopathy
• Hypovolemia
• Increased intracranial pressure
• Infection
• Patient refusal
• Stenosis :: mitral valve & aortic valve

Order of Nerve Blockade

• Small myelinated fibers
• Small unmyelinated fibers
• Large myelinated fibers
• Large unmyelinated fibers

Neuromuscular Blockade