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Neurology: Part I

Petey Nawrocki

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What We Will Cover

Sensing+Moving: Ascending and Descending Spinal Cord Tracts

What can go wrong?

Blood of the Brain

Circulation of the Brain
Stroke
Clinical Examples

Sleep
Neurocutaneous Disorders

Petey Nawrocki, Doctorials 2021/2022

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How Do We Get Sensations?

Two primary pathways:

Dorsal Column Medial Lemniscus

Proprioception
Vibration
Fine Touch
Pressure

Spinothalamic Tract (anterior, lateral)

Temperature
Pain
Crude Touch
Pressure

Peter Nawrocki, Doctorials 2021/2022

Amboss

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DCML Tract

Sensory nerve fibers have pseudounipolar cell body in dorsal root ganglion
Axon enters spinal cord, ascends ipsilaterally (same side)

T6 and below=via gracile fasciculus
T5 and above=via cuneate fasciculus (higher up is cute)

Decuss at medulla oblongata (ipsilateral), moves to opposite (contralateral) side

Peter Nawrocki, Doctorials 2021/2022

Teach Me Anatomy

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DCML Tract in Detail

Peter Nawrocki, Doctorials 2021/2022

Blumenfeld

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Spinothalamic Tract

Anterior: Crude touch + pressure
Lateral: Pain + temperature

Peter Nawrocki, Doctorials 2021/2022

Teach Me Anatomy

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Spinothalamic Tract

Peter Nawrocki, Doctorials 2021/2022

Blumenfeld

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How is Movement Initiated?

Peter Nawrocki, Doctorials 2021/2022

Blumenfeld

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UMN vs LMN

Upper motor neuron:

Originates in cerebral cortex or brainstem
Info carried to lower motor neurons to activate them ->makes contraction
UMN of motor cortex=main source of voluntary movement

Lower motor neuron:

In regions where synapsis with UMN occurs
Link between UMN↔muscle contraction

UMN lesion: Within CNS+spinal cord

No inhibition via GABAergic neurons

LMN lesion: Outside of CNS

No motor control to muscle

Peter Nawrocki, Doctorials 2021/2022

An upper motor neuron is:

-Found in cerebral cortex or brainstem

-Carries information down to activate lower motor neurons, which will control contraction of muscles

-UMN of cerebral cortex=main source of voluntary movement

A lower motor neuron is:

-Found in regions where synapsis w/UMN occurs

-Acts as link between UMN and muscles

LMN Lesion:

Occurs after the CNS- complete loss of motor control to muscle

From the brain stem, axons of LMNs extend through cranial nerves to innervate skeletal muscles of the face and head.

From the spinal cord, axons of LMNs extend through spinal nerves to innervate skeletal muscles of the limbs and trunk.

Key concepts

UMN can be in the brain or spinal chord

UMN connects to LMN and regulates it, LMN connects to tissue and exerts an action (ie. muscle contraction)

Upper motor nuerons regulate the amount of activity of lower motor nuerons by sending inhibtory GABA signalling.

UMN leads to lack of inhibitory signalling which means LMN stimuation of muscle is overactive= spasticity

In LMN lesions, there is no neural input to muscles, which leads to flaccid paralysis due to lack of resting muscle tone and subsequent atrophy from disuse

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Lateral vs Medial Motor Systems

Lateral:

-Lateral Corticospinal Tract

-Rubrospinal Tract

Control distal structures

Medial:

-Anterior Corticospinal Tract

-Vestibulospinal Tract
-Tectospinal Tract
-Reticulospinal Tract
Control proximal structures (axial, girdle muscles, also posture/balance/walking)

Peter Nawrocki, Doctorials 2021/2022

Blumenfeld

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Pyramidal Vs Extrapyramidal Tracts

Will begin in cortex, extrapyramidal nuclei
Pyramidal tracts: Originate in cerebral cortex, pass through medullary pyramids in medulla oblongata

Anterior/lateral corticospinal tract
Corticobulbar tract

Extrapyramidal: Originate in brainstem, carry motor fibers to spinal cord

Tectospinal
Rubrospinal
Vestibulospinal
Reticulospinal

Petey Nawrocki, Doctorials 2021/2022

Teach me Anatomy

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Pyramidal Tract: Lateral+Anterior Corticospinal

Peter Nawrocki, Doctorials 2021/2022

Teach me Anatomy

Controls movement of contralateral extremities
Origin from primary motor cortex

Premotor+supplementary motor areas

Travel to internal capsule (white matter pathway)

Midbrain->pons->medulla…
85% of UMN will:

Decuss at caudal medulla (level of foramen magnum) ->lateral (to anterior horn of spinal cord ->LMN->muscle movement

15% of UMN will:

Remain ipsilateral ->anterior (to cervical/thoracic level->decuss->LMN>muscle movement)

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Lateral+ Anterior Corticospinal Tract

Peter Nawrocki, Doctorials 2021/2022

Blumenfeld

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Corticobulbar Tracts: Also Pyramidal!

Motor function of non-oculomotor cranial nerves
Primary motor cortex->brain stem
Terminate @ motor nuclei of cranial nerves V, VII, IX, XII

Peter Nawrocki, Doctorials 2021/2022

Teach me Anatomy

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Extrapyramidal Tracts

Proximal axial/girdle muscles involved in postural tone, balance, head/neck movements, gait-related movements
Arise from nuclei in brainstem

Ipsilateral:

Vestibulospinal: Balance/posture (“antigravity” muscles”)

Lateral nuclei: Info on balance/posture->Innervate arm flexors/leg extensors
Medial nuclei: Innervate neck muscles (head position)

Reticulospinal: Muscle tone/voluntary movement control

Medial: Pons, ↑ voluntary movement and tone
Lateral: Medulla, ↓ voluntary movement and tone

Contralateral:

Rubrospinal: Function not entirely known

From red nucleus (midbrain)

Tectospinal: Moves head in relation to visual stimuli

From superior colliculus (midbrain)->signals from optic nerve
Cervical termination

Peter Nawrocki, Doctorials 2021/2022

-Originate in brainstem, carry motor fibers to spinal cord

-involuntary/automatic control of muscles (muscle tone/balance/posture/locomotion)

Vestibulospinal: Innervate “antigravity” muscles (flexors of arm/extensors of leg) ->balance + posture

-Have medial/lateral pathway

-Arise from vestibular nuclei

-Ipsilateral

Reticulospinal: Increases or decreases muscle tone, facilitates or inhibits voluntary movements

-Medial: from pons, facilitates voluntary movements, increases tone

-Lateral: From medulla, inhibits voluntary movements, decreases tone

-Ipsilateral

Rubrospinal: Function not entirely known, fine control of hand movements?

-From red nucleus (midbrain)

-Decussate as emerge

Tectospinal: Coordinates head movements in relation to visual stimuli

-From superior colliculus (midbrain)->gets signals from optic nerves

-UMN’s decuss, enter spinal cord, terminate at cervical levels

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Summary

Blumenfeld

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Basal Ganglia

Modulation/refinement of movements that we want
Subcortical nuclei:

Putamen
Globus Pallidus (internal+external)
Caudate
Subthalamic nucleus
Substantia nigra

Caudate+putamen=striatum
Globus pallidus+putamen=lentiform
Signals from cortex, negative feedback to cortex to modulate movement
Direct pathway: Increase in desired motor activity
Indirect pathway: Decrease in undesired motor activity

Peter Nawrocki, Doctorials 2021/2022

Teach me Anatomy

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Direct + Indirect Pathways

-

Peter Nawrocki, Doctorials 2021/2022

Teach Me Anatomy

First off: Hyperdirect pathway

Gpi excited -> thalamus + cerebral cortex inhibition of wanted and unwanted movements

Direct pathway: Thalamus activated to make desired movement

Glutamate → striatum
Striatum →GABA →Gpi
Gpi (cant release GABA), results in activated thalamus

Indirect pathway: Thalamus inactivated to make undesired movement

Glutamate → striatum
Striatum →GABA →Gpe
Gpe (cant release GABA), results in activated subthalamic nucleus
STN activates Gpi → can release GABA →inactivated thalamus

Substantia nigra: Release of dopamine to enhance these pathways

D1 receptor=on striatum for direct
D2 receptor=on striatum for indirect

The pedunculopontine nucleus (PPN) as a part of the midbrain, linked with the basal ganglia and corticospinal circuits. It inhibits muscle tone

Direct pathway:

In addition, the subthalamic nucleus stimulates the substantia nigra (pars compacta) → dopamine release → stimulation of D1 receptor in striatum → further inhibition of Gpi → inhibition of GABA release → thalamus disinhibition → premotor cortex stimulation → muscle activation → ↑ movement

Indirect pathway:

The striatum also stimulates the substantia nigra (pars compacta) → dopamine release → stimulation of D2 receptor in striatum → inhibition of GABA release → disinhibition of Gpe → GABA release → inhibition of subthalamic nucleus → ↓ stimulation of GPi → disinhibition of thalamus → ↑ movement

Now lets talk about the most important concept- how the basal ganglia function. This will allow you to understand why conditions such as parkinsons and huntingtons present the way that they do, and why their treatments work. I have included some information in the notes below this slide on the exact functions of every part of the basal ganglia as well as a short table on the various input and output nuclei. But, the most important thing for you to know about the BG right now is 1) there are three pathways which modulate movement, one (the hyperdirect) which you should be aware of but don’t need to know in detail and 2 (the indirect and direct, which you will need to firmly understand) 2) These are controlled by excitatory (glutamate) and inhibitory (gaba) nuerotransmitters 3) inhibition of inhibition leads to movement (we’ll explain this in the next slide 4) the modulatory effect of these pathways can be altered by the substantia nigra

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Cerebellum: Movement and balance

Info from spinocerebellar +vestibular tract (balance) → Output to descending movement tracts
Two hemispheres, connected by midline vermis
Dentate, emboliform+globose, fastigial (lateral →medial)

DON’T EAT GREASY FOOD
Information output

Peter Nawrocki, Doctorials 2021/2022

Conor Clancy, Doctorials 2020/2021

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Cerebellum: Movement and balance

Cerebrocerebellum: Planned movements of distal limbs, motor learning

Lateral cerebellar hemispheres
Cerebral cortex/pontine nuclei→CC→ red nucleus+thalamus
Lateral lesions (intention tremor, dysarthria)
“Arms”

Spinocerebellum: Proprioception

Vermis+intermediate zone
Golgi tendon organs+muscle spindles→SC→spinal cord
Medial lesions (staggering/wide based gait)
“backbone”

Vestibulocerebellum: Balance and ocular reflexes (fixation on target)

Vestibular appratus→VC →vestibular nuclei
Lesions: poor balance/nystagmus
“feet”

Peter Nawrocki, Doctorials 2021/2022

Conor Clancy, Doctorials 2020/2021

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What Can Go Wrong?

Peter Nawrocki, Doctorials 2021/2022

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Spinal Cord Pathologies: Key Points

Know your locale based on what you see

Lateral horn cutoff (T1-L2, sympathetics)
White matter/grey matter ratio in segments (least white matter in lower sacral segment)

Tract location (see below)

Symptoms based on areas damaged

Peter Nawrocki, Doctorials 2021/2022

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High Yield Spinal Lesions

Petey Nawrocki, Doctorials 2021/2022

First Aid 2021

Condition	Key points	Lesion Location
Werdnig-Hoffman Disease	-Anterior Horn Degeneration -”Floppy Baby”, symmetric hypotonia (LMN lesion) -Unlike poliomyelitis (polio)-> asymmetric
ALS (Amyotrophic Lateral Sclerosis)	-UMN (corticobulbar/spinal) + LMN (anterior horn) degeneration -Sensation spared -Dysarthria, dysphagia, resp difficulties
Anterior Spinal Artery Occlusion	-UMN deficit below lesion -LMN deficit at lesion (anterior horn) -Pain/temp loss below lesion (spinothalamic tract)
Syringomyelia	-Anterior white commissure affected (spinothalamic tract) -Loss of pain/temp bilaterally “cape”
Tabes Dorsalis	-Tertiary syphilis -Dorsal columns+roots affected -Proprioception affected->coordination lost
Vit B12 Deficiency	-Spinocerebellar, corticospinal, dorsal columns affected “Tabes Dorsalis + UMN symptoms”

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Friedreich Ataxia

Spastic paralysis

Lateral corticospinal tract

Ataxia

Spinocerebellar tract

Decreased vibration, proprioception

Dorsal Column

Deep tendon reflex loss

Dorsal root ganglia

GAA trinuc. repeats (chromosome 9)

Frataxin→mitochondrial dysfunction

Main cause of death: hypertrophic cardiomyopathy

Petey Nawrocki, Doctorials 2021/2022

First Aid 2021

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Quick Break!

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Brain Circulation + Strokes

Petey Nawrocki, Doctorials 2021/2022

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Cerebral Artery Origins

Anterior Circulation

Anterior Cerebral
Middle Cerebral

Posterior Circulation

Posterior Cerebral

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Circle of Willis

The internal carotid arteries, the anterior cerebral arteries, and the posterior cerebral arteries anastomose through the anterior and posterior communicating arteries to form the circle of Willis, a vascular circuit surrounding the optic chiasm and pituitary stalk. The circle of Willis equalizes the blood flow between the cerebral hemispheres and provides anastomotic circulation, connecting the anterior and posterior cerebral circulations and, thereby, permitting continued perfusion of the brain in the event of carotid occlusion

Circle of Willis: Anastomosis of ACA, Internal carotid, PCA

-Surrounds optic chiasm/pituitary stalk

-Functions to equalize blood flow between cerebral hemispheres, makes anastomic circulations between anterior/posterior circulations

-Allows continued perfusion of brain in event of carotid occlusion

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Homunculus-Focal Lesions

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Anterior Cerebral Artery

Supplies anteromedial cortex

Primary motor, primary sensory cortices
Frontal, parietal lobes

Rare to infarct (collateral circ. via anterior communicating artery)

Infarction results in:

Contralateral leg weakness
Contralateral leg sensation loss
Urinary incontinence
Left: Aphasia (if large enough)
Right: Hemineglect (if large enough)
Abulia

Petey Nawrocki , Doctorials 2021/2022

Neuroanatomy.ca

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Anterior Cerebral Artery

Petey Nawrocki, Doctorials 2021/2022

Neuroanatomy.ca

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Middle Cerebral Artery

Petey Nawrocki, Doctorials 2021/2022

Neuroanatomy.ca

Most common site of stroke
Most often in superficial divisions, lenticulostriate branches

Superficial:

Contralateral head, neck, trunk, arm weakness (motor cortex)
Contralateral head, neck, trunk, arm sensory loss (sensory cortex)

Dominant hemisphere: Brocas, Wernickes aphasia
Non-dominant hemisphere: Contralateral hemineglect

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Aphasia

Inability to understand, produce, use language appropriately

No motor dysfunction in vocal apparatus
Dominant hemisphere damage (often left)

Broca’s area: Plans sequences of sounds to be made “production”
Wernicke’s area: Picks up sounds, comprehends as words “comprehension”

Petey Nawrocki, Doctorials 2021/2022

Blumenfeld

	Broca’s Aphasia	Wernicke’s Aphasia
Location	Inferior Frontal Gyrus	Superior Temporal Gyrus
Sound fluent?	N	Y
Insight?	Y	N
Repetition?	N	N
Features	Broken, grammatically incorrect speech, pt frustrated	Speech doesn’t make sense (word salad, “flush” instead of “brush”

Unlike dysarthria (difficulty in articulation due to incoordination/weakness of musclulature of speech, with language being normal), dysphasia is an impairment of language -> Brocas, Wernickes aphasia

Left hemisphere is dominant for language in 95% of right handers and 60-70% of left handers
Articulation of sounds for speech depends on the face area of the primary motor cortex, however the motor program that activates particular sequences of sounds to produce words and sentences is formulated in the adjacent association cortex called broca’s area
Auditory information reaches the primary auditory cortex in the temporal lobe, but Wernicke’s area will allow for processing and enabling the particular sequence of sounds to be identified and comprehended as meaningful words
The ability to hear a word and then repeat it out load requires transfer of information from Wernicke’s area to broca’s area

Sounds are converted into words in Wernicke’s area
Words are converted back into sounds in Broca’s area
The two areas communicate with each other via the white matter tract called the arcuate fasciculus

Adapted from Casey Goldstein, Neurology I Doctorials 2020/2021

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Lenticulostriate Artery

Arising from Middle Cerebral Artery
Basal Ganglia, Internal Capsule

Pure contralateral hemiparesis

Lacunar infarction high risk zone

Small vessel blockage
Via hyaline arteriolosclerosis (unmanaged HTN)

Petey Nawrocki, Doctorials 2021/2022

Blumenfeld

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Posterior Cerebral Artery

Occipital lobe, inferior temporal lobe

Contralateral homonomous hemianopsia with macular sparing

Thalamus, internal capsule (if big enough)

Contralateral hemisensory loss, hemiparesis

Alexia without agraphia: Loss of reading comprehension, without loss of writing

Left PCA (dominant hemisphere)
Corpus callosum region affected

Prosopagnosia: Cant recognize familiar faces

Right PCA (non dominant hemisphere)

Peter Nawrocki, Doctorials 2021/2022

Neuroanatomy.ca

Why is macular region spared??

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Strokes of Brainstem: Rule of 4’s

4 CN in midbrain, pons, medulla
Midline CNs divide into 12:

CN 3, 4, 6, 12

Lateral CNs do NOT divide into 12:

CN 5, 7, 8, 9, 10, 11

Midline structures start with “M”:

Motor pathways (corticospinal) + motor nuclei
MLF->Aligning horiz. eye movements
Medial lemniscus->vibration, proprioception

Lateral (side) structures start with “S”:

Sympathetic chain (dilation/sweating)
Spinothalamic
Sensory
Spinocerebellar

Casey Goldstein, Doctorials 2020/2021

Peter Nawrocki, Doctorials 2021/2022

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Basilar Artery

Medial pons

Corticospinal, corticobulbar tracts

Face, mouth, tongue movements
Quadriplegia

CN VI

Ipsilateral Loss of horizonal eye movements
Vertical is spared

Dorsal column, MLF also affected

Supplies most of Pons
Union of vertebral arteries

Gives off Anterior Inferior Cerebellar Art.

Locked-in Syndrome: RAS spared

Communication by blinking, vertical eye movements
May completely recover

Petey Nawrocki, Doctorials 2021/2022

First Aid 2021, Blumenfeld

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Anterior Inferior Cerebellar Artery

Peter Nawrocki, Doctorials 2021/2022

First Aid 2021, Blumenfeld

Lateral pons, anterior inferior cerebellum

Middle +Inferior Cerebellar peduncle (spinocerebellar pathway)

Ipsilateral ataxia, dysmetria

Spinothalamic tract

Pain/temp sensation loss (contralateral)

CN V sensory nucleus

Facial sensation loss (ipsilateral)

Sympathetic fibers

Ptosis, miosis, anhidrosis (Horners syndrome) ipsilaterally

CN VIII nuclei

Vomiting, vertigo, nystagmus

Facial nerve nucleus

Facial weakness (ipsilateral)
↓ lacrimation, salivation, taste
Facial droop means AICA’s pooped

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Posterior Inferior Cerebellar Artery

Lateral medulla, posterior inferior cerebellum (branch from vertebral art.)

Inferior Cerebellar peduncle (spinocerebellar pathway)

Ipsilateral ataxia, dysmetria

Spinothalamic tract

Pain/temp sensation loss (contralateral)

CN V sensory nucleus

Facial sensation loss (ipsilateral)

Sympathetic fibers

Ptosis, miosis, anhidrosis (Horners syndrome) ipsilaterally

CN VIII nuclei

Vomiting, vertigo, nystagmus

Nucleus ambiguus (CN IX, X, XI)

Dysphagia, hoarseness, ↓ gag reflex, uvula deviation
Bulbar palsy (Wallenburg syndrome)
Don’t pick a (PICA) horse (hoarse) that cant eat (dysphagia)

Peter Nawrocki, Doctorials 2021/2022

First Aid 2021, Blumenfeld

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Anterior Spinal Artery

Medial medulla

CN XII

Ipsilateral tongue weakness
Deviates to affected side

Medial lemniscus

Contralateral proprio, vib, FT, pressure loss

Motor tracts (corticospinal)

Contralateral upper/lower limb paralysis

Peter Nawrocki, Doctorials 2021/2022

First Aid 2021, Blumenfeld

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Clinical Examples

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A 67 yo pt presents to your office with a 2 hr history of altered mental status. He was found unresponsive on the couch while watching Jeopardy. On physical exam, you note 4/5 motor strength of the left lower extremity, 0/5 motor strength of the right lower extremity, and 5/5 motor strength in both upper extremities. He has intact sensation to all facial muscles and can puff out cheeks, swallow, smile. His gag reflex is intact, and there is no tongue or uvula deviation. Which of the following is the type of stroke experienced by this patient?

A: Right anterior cerebral artery stroke

B: Left anterior Cerebral artery stroke

C: Right middle cerebral artery stroke

D: Left middle cerebral artery stroke

E: Right lateral medullary stroke

Peter Nawrocki, Doctorials 2021/2022

Dirty USMLE

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A 76 y/o patient presents to your clinic with an 8 hour history of diffuse motor weakness on his entire right side. He is asked to look to the left, findings are shown below. Which of the following best categorizes his stroke?

A: Left medial pontine stroke

B: Right medial pontine stroke

C: Left lateral Midbrain Stroke

D: Right Anterior Cerebral Artery

Peter Nawrocki, Doctorials 2021/2022

Dirty USMLE

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Sleep

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Sleep Physiology

Circadian rhythm dependent

Suprachiasmatic Nucleus (Hypothalamus) → regulated by light
ACTH, prolactin, melatonin, norepinephrine
Releases NE→pineal gland →melatonin release

Blue light (400-535 nm) inhibition

Balance between Reticular activating system (RAS) of midbrain, Hypothalamus and its nuclei
RAS:

Nucleus coeruleus-> Takes in orexin to ++alertness
Raphe nuclei->serotonergic neurons, direct communication w/SCN
PMCT complex->High frequency waves
Tuberomammillary nucleus

Hypothalamus:

Lateral hypothalamus -> Orexin (alert)
VLPO -> RAS component inhibition via GABA
SCN

Teach Me Physiology

RAS of brainstem=controls alertness, wakefulness, attention

Nuclei include:

-Nucleus ceruleus: Contains NE neurons projecting to cerebrum/cerebellum, regulates wakefulness and arousal, excited by orexin from lateral hypothalamus

-Raphe nuclei: Direct communication w/SCN and hence circadian rhythm regulation

-PMCT complex: Pons/midbrain, projections to thalamus/cortex to shift slow waves->higher frequency awake rhythms

-Tubermammilary nucleus: Histaminergic neurons

SCN: Above optic chiasm in hypothalamus, takes in visual stimuli from retina, is major circadian clock

Lateral hypothalamus: Secretes orexin (REM inhibition, wakefulness++)

Ventrolateral preoptic nucleus: Inhibits RAS components (sleep++) via GABA secretion

-Consists of 4-5 sleep cycles, including 3 stages of Non rapid eye movement (NREM) sleep and one rapid eye movement stage (REM)

** HY tips

-Phases, waves

-When bruxism, sleepwalking, nightmares occur

-cite TEACH ME PHYSIOLOGY https://teachmephysiology.com/nervous-system/sensory-system/consciousness-and-sleep/

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Sleep Cycle

Peter Nawrocki, Doctorials 2021/2022

USME FA 2021, AMBOSS

N3 + REM sleep disruptors:

Alcohol, benzodiazepines, barbiturates (naughty 3 decrease N3)
Norepinephrine (REM only)

Important for GEMS (and USMLE)

Phases, waves in each
When does bruxism, sleepwalking, nightmares occur?
Changes in elderly, depression

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Sleep Cycle Disorders

Peter Nawrocki, Doctorials 2021/2022

Condition	Def’n	Cause	Presentation
Delayed Sleep-wake Phase Disorder	Consistent sleep-wake onset time delay	Circad. Rhythm malfunction (caffeine, puberty)	Difficulty falling asleep, wakes late (no night waking)
Insomnia*	Bad quality/quantity of sleep, making daytime dysfunction	-Hyperarousal -Depression, anxiety	Cant fall, stay asleep Early rising
Narcolepsy*	Daytime sleepiness + rapid-onset sleepiness episodes, but feel rested	↓Orexin (from LH)	-Hypnogogic, hypnopompic hallucinations -Cataplexy
Sleepwalking Disorder	Perform activity in sleep (first 1/3 cycle)	-Stress -Sleep deprivation	-Amnesia of event
Sleep terror Disorder*	Waking w/feelings of terror	-Stress -Fever -Sleep deprivation	-Scream/cry upon waking (early in night) -nonREM -No memory

Dyssomnia: Difficulty falling/staying asleep, or hypersomnia

Parasomnias: While falling asleep, during, waking up

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Neurocutaneous Disorders

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Neurocutaneous Disorders

Ectoderm cells

Skin
Nervous System
Eyes

Other organs affected

Sturge-Weber
Tuberous Sclerosis
Neurofibromatosis
Von Hippel-Lindau Disease
Autosomal Dominant inheritance (Except SW=nonhereditary)

Peter Nawrocki, Doctorials 2021/2022

AMBOSS

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Sturge-Weber Syndrome

Congenital anomaly of neural crest cell derivatives

GNAQ gene somatic mosaicism

‘”Port wine stain” (A)

Capillary malformation

Seizures/epilepsy, intellectual disability

Leptomeningeal angioma (B)

Early onset glaucoma

Peter Nawrocki, Doctorials 2021/2022

First Aid 2021

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Tuberous Sclerosis

Autosomal dominant
Mutation of tumor suppressor genes:

TSC1: Hamartin (chromosome 9)
TSC2: Tuberin (chromosome 16)

HAMARTOMASS

Angiofibromas (C)
Ash-leaf spots (D), Shagreen patches
Renal Angiolipomas

Peter Nawrocki, Doctorials 2021/2022

First Aid 2021

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Neurofibromatosis

Neurofibromatosis I
Cutaneous neurofibromas (G)

Nerve sheath tumors, affect myelinated nerves

Lisch nodules (H)
Optic gliomas (vision loss)
Pheochromocytoma (neural crest dysfunction)

NF1 tumor suppressor gene mutation (chrom. 17) -> Neurofibromin

Neurofibromatosis II
Bilateral vestibular schwannoma

Hearing loss, tinnitus

Juvenile cataracts
NF2 affects 2 ears, 2 eyes

NF2 tumor suppressor gene mutation (chrom. 22) ->Merlin

Peter Nawrocki, Doctorials 2021/2022

First Aid 2021

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Von-Hippel Lindau disease

VHL gene deletion on chromosome 3p

Ubiquitination of hypoxia-inducible factor 1a compromised

More hypoxia-inducible factor 1a=too much angiogenesis!

Hemangioblastomas (J)
Retina, brainstem, cerebellum, spine
Hyperchromatic nuclei (I)

Also associated with

Bilateral renal cell carcinomas
Pheochromocytoma

Peter Nawrocki, Doctorials 2021/2022

First Aid 2021

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Questions?

19122063@studentmail.ul.ie

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References

Blumenfeld, H., n.d. Neuroanatomy Through Clinical Cases.
Neuroanatomy.ca
Le, Tao and Bhushan, Vikas. First Aid for the USMLE Step 1 2021, Thirty First edition. New York: McGraw-Hill Education, 2021.
Teachmeanatomy.com
Amboss.com