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Neuro Path Flashcards

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1
Q

Neural Development

A
  • Notochord induces overlying ectoderm to become neuroectoderm. Becomes plates with crest cells, then fold to generate neural tube.
  • Notochord remains as NP.
  • Alar is sensory and Basal is motor.
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2
Q

Structures of developing Brain

A 
Forebrain:
 - telencephalon - Hemispheres and lateral ventricles
 -diencephalon - 3rd ventricle
Midbrain:
 -Mesencephalon - Midbrain, aqueduct
Hindbrain (rhombencephalon)
 -Metencephalon - Cerebellum and pons (4th Ven)
 -Myelencephalon - Medulla (4th vent)
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3
Q

Neural Tube Defects

A
  • All related to decreased folate at the time of conception.
  • All will present with elevated AFP and elvated AchE
  • Valproate and carbemazapine may also cause neural tube defects
  • SBO: No arch of vertebral body
  • Meningocele- Meniges protrude
  • Meningomyelocele - Meninges and chord protrude. Leads to paralysis below lesion. Often occompanied by Chiari 2 formation and syringomyelia.
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4
Q

Anencephaly

A
  • Failure of cranial neuropore to close. Folate involved.
  • Elevated AFP and polyhydramnios
  • Associated with Maternal DM1
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5
Q

Holoprosencephaly

A
  • Failure of separation of cerebral hemispheres.
  • Can cause cycloplegia and cleft lip and palate
  • Associated with Patau Syndrome
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6
Q

Chiari (II)

A
  • Chiari 1 is often clinically silent. Slight decrease in posterior fossa formation.
  • Chiari 2 - Herniation of cerebellar vermis through foramen magnum.
  • stenosis of 4th ventricle and noncommunicating hydrocephalus
  • Syringomyeleia and Myelomeningocele
  • There will often be paralysis below defect
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7
Q

Dandy Walker

A
  • Agenesis of the cerebellar vermis leads to cystic dilation of the 4th ventricle.
  • Hydrocephalus
  • Associated with spina bifida.
  • Presents with vommiting and convulsions secondary to increased ICP
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8
Q

Syringolmyelia

A
  • Cystic dilation of the central canal
  • Generally occurs in the thoraco cervical region
  • Loss of P/T in capelike distribution, generally involving back and hands. Due to loss of anterior white commisure of crossing spinothalamic fibers.
  • Associated with Chiari 1,2 and myelomeningocele
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9
Q

Tongue Development and Sensation and Motor

A
  • Branchial Pouch 1 - Muscles and sensory for CN V3. Makes the anterior 2/3 of tongue and general sensation. Special sensation via chorda tympani (7)
  • Branchial Pouch 3 and 4 Make posterior tongue. 3 is done by CN9 and 4 by CN10. CN9 does most taste ans sensation while 10 does the very posterior (nucleus solitarius)
  • Foramen cecum (thyroglossal duct) and sulcus terminalis (circumvalate papilla) divide the anterior and psoterior portions of the tongue
  • Motor innervation by hypoglossal (12) come from occipital myotomes. Damage will cause deviation towards the side of the lesion (genioglossus unoposed)
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10
Q

Wallerian Degeneration

A

Destruction of an axon leads to dissolution of distal portion and retraction of the proximal portion.

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11
Q

Chromatolysis

A

In response to axonal injury the Nissl substance breaks apart and the nucleus is displaced laterally.

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12
Q

Acute ischemic death in neurons

A

Eosinophilia and an analog of coagulative necrosis with pyknosis and karryorexis.

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13
Q

Diffuse Axonal Injury

A
  • Widespread destruction of white matter in brain. Often leads to vegatative state.
  • Shaken baby or TBI
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14
Q

Astrocytes

A
  • Maintain BBB with foot processes, regulate K concentration and assist in NT reycling and clearance.
  • Marker is GFAP present in many cancers.
  • Reactive gliosis
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15
Q

Microglia

A
  • Mesodermally derived, function as macrophages of CNS

- Site for HIV brain infection, will show large multinucleated cells.

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16
Q

Oligodendrocytes

A
  • Myelinate in CNS, can myelinate many neurons at once.
  • Destroyed in MS
  • Tumor looks like fried eggs
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17
Q

Schwann Cells

A
  • Neural Crest Derived
  • Myelinate in periphery and can aid in regeneration. Myleinate a single neuron at a time.
  • Damaged in Guillan Bare
  • Schwannomas are characteristic of NF diseases. Bilateraly vestibular in NF2
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18
Q

Sensory Receptors

A
  • Free: A delta (mylinated) C - Pain sensation, present nearly everywhere except minimal in GI
  • Meisners Corpuscles: Light touch, enriched on glaborous skin. Rapidly adapting
  • Pacinian Corpuscles: Deep Skin: Vibration and pressure
  • Merkels Disks: Slowly adapting deep pressure and position
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19
Q

Peripheral Nerve Layers

A
  • Endoneurium surrounds each nerve (location of Guillan Bare Inflammation)
  • Perineureum surrounds a fascicle, needs to be rejoined for nerve regeneration
  • Epineurium: Strong CT
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20
Q

NE, diesase and Location

A
  • Made in locus cerruleus in pons

- Decreased in depression and increased in anxiety

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21
Q

DA, disease and location

A
  • Increased in psychosis, decreased in parkinsons and depression.
  • Ventral tegmentum (midbrain) and SNC
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22
Q

5-HT

A
  • Majority in gut, in brain. Decreased in depression and decreased in anxiety
  • Raphe nucleus (pons)
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23
Q

Ach

A

-decreased in alzheimers and huntingtons. Nucleus of meynert

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24
Q

GABA

A
  • Decreasd in huntingtons and anxiety

- Present in nucleus accumbens

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25
BBB
- Endothelial Cells, BM, Astrocyte foot processes - Allow lipophilic substances, hydrophilic need transporter (glucose/aa, etc) - Discontinuous at: Area postrema, osmolar sensors hypothalamus, releasing centers of post pit - Damage leads to vasogenic edema
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Hyropathalmic Nuclei
- Anterior - Cooling body temperature regulation (PANS). Also contains inputs from mamillary body as part of papez circuit. - Posterior- Heating body temperture (SANS) - Lateral - Hunger centers. Inhibited by leptin and destruction leads to anorexia and depression - Ventromedial - Satiety center. Damage leads to hyperphagia and aggressive behavior. (craniopharyngoma) - Suprachiasmatic - Circadian rythms, ADH production. OVLT zone that senses osmolality (Weak BBB) - Suproptic - Sexually dimorphinc nucleus GnRH - Paraventricular - Oxytocin - Dorsomedial - Connections with orbitofrontal, smell and emotions, regultes BP, HR and GI (like VM with smell) - Aruate: Dopamine (PRL) and GHRH
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Posterior Pituitary
- ADH released, created in superchiasmatic hypothalamus | - Oxytocin released, made in paraventricular
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Craniopharyngoma
- Tumor of surface ectoderm (epithelium) that was rathkes pouch (made anterior pituitary) - Commonly presents in children as bitemporal hemianopia. May cause damage to hypothalmic structures and produce with their specific signs. - Usually appears calcified on imaging.
29
Pituitary Adenoma
- Tumor of a specific type of cell in the AP. - Most commonly secretes nothing, but does commonly secrete PRL. - Most common in adults, presents as bitemporal hemianopia or ammenorrhea in women.
30
Wernicke Encephalopathy
- thiamine deficency in alcoholics - Lesions of mamillary bodies of diencephalon - Occular palsies, ataxic gate, and confabulations
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Thalamic Sensory Nuclei
- Recieve information and send to brain - VPL: Recieves all Sensory from body (P/T and Fine) DCML and ST - VPM: Sensory from face (CN 5) and taste (CN 7,9,10) - MG: Hearing, recieves input from superior olive and inferior colliculus (gaze reflexes). Outputs to temporal Lobe - LG: Vision from optic nerve, projects to calcarine sulcus in occipital lobe.
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Thalamic Motor Nuclei
VA/VL: VL is main output to cortex, VA is reciprocal with BG and Cerebellum
33
Thalamic Lesions
-Most commonly due to infarction from lenticulostriate (perforating branches of MCA) Lacunar HTN, and will result in contralateral loss of the given function.
34
Limbic Constiutuents
- Generates emotions, long term memory, smell, autonomics, | - Mamillary Bodies, Hippocampus, Amygdala, Cingulate Gyrus,
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Papez circuit
-Hippocampus to mamillary bodies via Fornix. Then to anterior hypothalamus, to cingulate gyrus, to entorhinal cortex to hypothalamus
36
Wernicke Encephalopathy
-Hemorrhagic destruction to mamillary bodies due to severe thiamine deficency. Most commonly seen in alcoholics -Occular dysfunction, ataxia, confabulations
37
Kluver-Bucy
- Damage to the anterior temporal lobe (amygdala) results in hyperphagia, hypersexuality, docility. - Most commonly caused by HSV (Likes to cause temporal lobe encephalopathy) in AIDS pts. - Can also be caused by trauma and tumor
38
Foster Kennedy
- Increased ICP leads to damage of the optic nerve and the olfactory tracts - Presents with anosmia and visual disturbances - Caused by increased ICP (Tumor, etc)
39
Hippocampal Pathology
- Common site of siezure initiation - Earliest site of damage in alzheimers - Very sensitive to hypotension and hypoxia
40
Cerebellar Function and anatomy
- All function is ipsilateral. - Inferior peduncle is sensory from ipsilateral cord - Middle is from contralateral cortex input - Superior is output to contralateral cortex - Perkinje cells are only cells with output and it is inhibitory on VA/VL thalamus
41
Cerbellar parts
- Vermis functions for trunkal balance and outputs to the fastigal nucleus - Paravermal is for trunkal and limb balance and outputs to eboliform and globos - Lateral hemisphere is for coordination of movements of the limbs, outputs to dentate. Largest and most extensive connections - Anterior is descending postural information, Posterior is information to cerebral cortex for motor planning and higher order functions - Folculonodular is for balance and vestibular system
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Cerebellar Injury
- Alcohol is most common and damages anterior vermis. Damages leg balance. Trunkal ataxia. - Cerebellum is common site of tumor in kids - Posterior cerebellar syndrome - upper trunkal ataxia - Lateral Syndrome ataxia of ipsilateral side. Seen falling to ipsilateral side.
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Basal Ganglia Structures
- Input from cortex to Caudate and Putamen. - Caudate and putamen also recieve input from SNc - Output is inhibitory only and via gpi/snr
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Excitatory Pathway
-D1 receptors on striatum recieve input from snc. Leads to inhibition of Gpi/Snc. Which removes inhibiton of thalamus
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Inhibitory BG
- D2 receptors inhibit the inhibitory pathway in striatum. - Normally pathway has positive influence on STN which leads to increased stimulation of gpi/snr which leads increased inhibition of thalamus.
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Parkinsons
- Depletion of dopaminergic neurons in snr. - Can't initiate movement. Leads to bradykinesia, resting tremor, gait instablity. - Pathology shows lewy bodies with alpha synuclein inclusions. - Late in the disease dementia will develop
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Supranuclear Palsy
-Tau body formation with parkinson symtpoms and occular impairment. Tau will be present in BG and Brain stem
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Tardive Dyskinesia
- Often permanent effect of antipsychotics that occurs because of increased sensitivity of dopamine in nigrostriatal pathway. - Usually begins with mouth smacking and results in complete atheosis. Less common with atypical antipsychotics
49
Huntingtons Disease
- AD CAG repeat leads to death of cells in the caudate and caudate atrophy. Mediated by glutamate toxicity and NMDA-R. - Shows anticipation with increasing CAG repeats occuring during spermatogenesis. - Presents with athetosis that wil progress to aggression, depression, often commit suicide. - Loss of GABA and Ach
50
Hemibalism
- HTN induced lacunar infarct of STN. Loss of STN is a loss of inhibitory pathway. - Flinging athetotic movements. - Lesion is in contralateral STN
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Myoclonus
- Unsustained spasm of muscle - Common and seen in siezures - Rapid slow wave depolarization on EEG - Seen in Critzfeld Jacob and other prion diseases
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Dystonia
- Sustained spastic contraction of muscle | - Can treat with antiepileptic drugs and muscle relaxants.
53
Essential Tremor
- Tremor that is present at rest minimally and gets worse if try to hold in same position. - Ethanol, beta blockers, and barbituates decrease.
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MTPT
Street drug with metabolites that destroy neurons in snc. Parkinsons
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Wilsons Disease
- Hepatolenticular degeneration. - Copper deposits in basal ganglia and other structures - Normally seen in 20's with dementia, psychosis, and athetosis. - Tx Peniclamine
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Brocas Aphasia
Damage to the speech area on the dominant hemisphere in the frontal cortex. Motor aphasia. - Can still comprehend but can't speak - MCA stroke
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Wernickes aphasia
- Damage to speech area in temporal lobe. - Receptive or sensory aphasia - Occlusion of MCA
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Conduction Apashia
-Damage to arcuate fassiculus which connects wernicke's and brocas area. -Can't repeat, but can recieve and speak MCA
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Gerstmanns syndrome
- Damage to inferior parietal lobule on domninat side. - Agraphia and acalcula - MCA
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Spacial Neglect Syndrome
- Damage to nondominant side inferior parietal lobule results in hemineglect - MCA
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Frontal Lobe Function and Damage
- Higher order processing and motor functioning - Personality changes and cognitive changes - Disihibition and return of primative relexes - MCA or ACA - Also motor
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Reticular Activating System
- Located in midbrain, contains extensive cholinergic and adrenergic synapses. - Damage leads to coma
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Hippocampal Damage
- Anterograde amnesia is first sign | - Trauma, alzheimers
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PPRF
- Lesion will cause nystagmus and occular gaze problems. | - Eyes will deviate away from lesion
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Frontal Eye Field Damage
- Saccade damage and occular impairment | - Eyes will deviate towards lesion
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Central Pontine Myelinolysis
- Extensive demylination of the pons, will appear as hyperintense on T2 weighted image - Due to too rapid of correction in Na concentrations. Alcoholics or severely malnourishe - Causes locked in syndrome.
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Overview of ACA
- Arises from anterior circle of willis and supplies the inferior and medical aspects of the frontal and some parietal lobe. - Occlusion will lead to loss of motor and sensory in the feet and legs (Homunclulus)
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Overview of MCA
- Supplies the lateral frontal lobe, parietal, and some temporal - Most commonly infarcts in smaller feeder arteries. - Comes off internal carotid quickly so is common source of embolism and thrombus - Will cause loss of motor and sensory to upper body and face (homunculus)
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Overview of PCA
- Branch off vertebral artery, does communicate via circle of willis - Supplies midbrain, temporal lobe, occipital lobe
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Watershed areas
- Upper leg and arm weakness (ACA/MCA) | - Higher order processing (MCA/PCA)
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Regulation of Cerebral Blood Flow
- Mainly autoregulation - pCO2 greatly controls flow - Dilates with increased pCO2 - Hyperventilation will lead to dilation of vessels by decreasing pCO2. - At extremely low O2 saturation there will be dilation of cerebral vessels.
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Lateral Striate Artery obstrucion
- Most commonly caused by HTN and hyaline arteriolosclerosis - Generates lacunar infarcts - BG, Internal Capsule - Effects will be contralateral - Anterior internal capsule is relay between BG, Cortex, Cerebellum. - Genu- corticobulbar fibers (face paralysis) - Posterior Limb - Corticospinal fibers leads to focal paralysis. (posterior also contains some optic and acoustic fibers.) Also contains blood supply from the internal carotid directly (anterior choroidal)
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Anterior Spinal Artery Infarction
- Caudal Medial Medulla - Loss of Motor from contralateral body, DCML - Loss of hypoglossal nerve 12 - No motor or fine sensation, tongue deviates to the ipsilateral side
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PICA infarction
- Lateral Medullary Syndrome - Loss of: Vestibular, 9,10, (Nucleus Ambiguus), ST, SANS, Inferior cerebellar peduncle, Spinal 5. - Loss balance, vertigo, nasuea (8), Fine touch contralateral body, Ataxia, dysmetria, P/T to face. Horners. - Gag reflex, P/T contralateral body distinguish from AICA.
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AICA
- Lateral inferior pons: - Loss of 7,8. Middle/inferior cerebellar peduncles, SANS, Spinal 5 - Loss P/T to face, vertigo (8), ataxia/dysmetira, horners - Loss hearing (cochlear), Facial motion (reflexes, tearing) ditinguish from PICA
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PCA
- Occipital cortex | - Hemianopia with macular sparing
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PCA paramedian
- Damage to midbrain - CN 3, 4, UMN of 7 - Loss of motor to contralateral lower face.
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Medial branches of basilar caudal pons
-DCML, Corticospinal, Abducens
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Prinauds
- Tumor of pineal gland (pinealoma or dysgerminoma) often calcified on imaging - Hydrocephalus - Superior Colliculus : Upward and downward gaze palsy
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Schwannoma
- Occurs at cerebellopontine angle. Involves CN 8. May not damage 7. - Occurs bilaterally in NF2 - Classically: hearing loss and balance 8, spinal 5
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Jugular Foramen Syndrome
- Can be from thombosis or compression - 9,10,11 - Loss of gag reflex and shoulder shrug (head will be weak when turning opposite side of lesion)
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Subclavian Steal
- Thombosis or compression of subclavian reduces perfusion through vertebral artery. - During exercise there will be pain in left arm. There will also be dizziness and vertigo.
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Anterior Communicating
- Connects ACA to Internal Carotid/MCA - Most common site of saccular anyeurisms. - Anyeruism may compress optic chiasm leading to bitemporal heminaopia. - Rupture of anyeurism leads to SAH with worst headache of life - Gives off medial striate arteries which supply BG/Thal
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Posterior Com
- Connects PCA and verterobasilar system to internal carotid system - Second most common site of berry anyeurism, compress CN3.
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Anterior Choroidal
- Off of internal carotid - Supplies posterior limb of internal capsule (Motor) - Common location of charcotbreusard microanyeurism and HTN arteriolosclerosis leading to lacunar infarcts. Leads to motor and sensory loss that is isolated.
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Berry Anyerurism
- Most common ant communicating branch points (lack media) - Rupture leads to SAH with worst headache of life. - Increased risk with HTN, APKD, Marfans, Ehlers danlos, smoking.
87
Epidural Hematoma
- Bleeding outside of brain dura. High pressure arterial creates lens shape. Does not cross suture lines. - Classically rupture of middle meningeal (branch maxillary through foramen spinosum) due to fracture of temporal bone. - Presents with lucid period that is followed by precipitous decline due to herniation. - Herniation is often transtentorial and causes CN3 palsy.
88
Subdural Hematoma
- Occurs due to rupture of bridging veins and bleeds subdurally. Low pressure venous. Can cross suture lines - Most common in elderly because of brain atrophy. Also seen in shaken babies, trauma. - Bleed is slow with progressive neurologic signs. - May cause herniation
89
Subarachnoid Hematoma
- Caused by rupture of berry anyeurism - Bleed into Subarachnoid space, presents with worst headache of my life, red/yellow csf, and nuchal rigidity. - 2-3 days post bleed, blood breakdown products may cause vasospasm and subsequent neuro signs. Treat with Ca channel blocker nimodipine to prevent rebleed.
90
Intraparenchymal Hemorrhage
- Due to rupture of charcot brousard microanyeurisms. - Commonly secondary to HTN and creates lacunar infarct. Also seen in cererbral arterial amyloidopathy, vasculitis, neoplasm. - Most common location is BG and internal capsule (lenticuostriate off MCA and anterior choiroidal off IC)
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Global Ischemia
- Bouts of hypotension or hypoglycemia - Transient confusion and lightheadedness - Most vulnerable are pyramidal cells: Perkinje in cerebellum, 3,5,6 Cortex, Hippocampus
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Immediate appearance of infarction
- Pale is from atherosclerotic thrombi (most common in cortex of MCA branches) - Embolic will lead to hemorrhagic stroke upon clot dissolution - Hemorrhage-tumor etc - Lacunar: Microanyerusism. Most common in BG and Internal capsule (lenticlostriate)
93
Evolution of Neuronal Damage in stroke
- Eventual result is liquefactive necrosis with cystic lesion. - 12-24 hrs there will be red neurons with pyknosis of nucleus and intense eosinophilia - 1-2 days is influx of neutrophils - 3-5 days is influx of microglia - 1-2 weeks is granulationt tissue and influx of astrocytes - 2 weeks plus is the formation of glial scar (inhibits regeneration but maintains BBB integrity)
94
TIA
- Brief period less than 24 hours of acute changes with complete resolution. Will not be evident on MRI - CADASIL is mutation in Notch 3 and is the most common cause of heredtery stroke risk, defect in smooth muscle function. TIA are common in young individuals and MRI will often show multiple infarcts (most often ischemic) common cause of vascular dementia.
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Venous Sinuses
-Straight, sagital, transverse drain to confluence. Then into sigmoid and finally into jugular foramen.
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Ventricular System
- Production of CSF by ependymal cells in choroid plexus. - Flow from lateral ventricles, through interventriular foramen to 3rd ventricle, through aqueduct to 4th ventricle. Out 4th ventricle through magendie/lushka into Subarachnoid space. - Reabsorbed via arachnoid granulations in venou sinuses. - Large resivoirs of subarachnoid space called cisterns
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CSF compared to plasma
- Increase in Na and Cl | - Decrease in K, Ca, glucose, protein
98
Noncommunicating Hydrocephalus
- Blockage leading to accumulation behind blockage | - Tumors, Chiari, Dandy Walker, Congenital stenosis
99
Communicating hydrocephalus
- Caused by increased production due to ependymoma (rare) - Imparied resorption by arachnoid granulations, post menintitis - Increased ICP, papilledema, herniation (can also occur with noncommunicating)
100
Normal Pressure Hydrocephalus
- Most common in middle aged women. - CSF with normal pressure, dilation of ventricles - Wacky wobbly, wet due to compression of corona radiata
101
Hydrocephalus ex vacuo
- Decreased volume of brain parenchyma leads to elevatd levels of CSF - Not clincally significant, more of a sign. - Huntingtons, Alzheimers, HIV, Picks disease.
102
Spinal Cord ends
- L1/L2 do LP at L3-L5 | - ends at L3 in kids and differential growth changes.
103
Spinal Tract Locations
- DCML: ascends ipsilaterally in cuneatus (lateral) and gracilus (medial) - Corticospinal: Descends laterally at midlevel (1st order crosses in caudal medulla). Legs are lateral and arms are medial - ALS: Crosses over at spinal cord (synapse in substatia gelatinosa and cross in anterior white commisure) ascends anterior (crude touch) and lateral (Pain/Temp) with legs lateral and arms medial. - Sympathetics from T1-L2/3 run in medial gray.
104
Babinski
- Flexor is normal and negative | - Extensor is positive and abnormal
105
Spinal Cord Lesions
-polio, Werdnig Hoffman (SMA), ALS, Tabes Dorsalis, Syringomyelia, Subacute Combined Degeneration, ASA syndrome, Freidrichs ataxia, MS, Brown Sequard, Horners
106
Poliomyelitis
- Caused by infection with positve stranded RNA virus. Infection by fecal oral route. Oropharynx and gut IgA are main defense. Disseminates to CNS via the blood. CNS will show elevated WBC. - Destruction of anterior horn cells leads to flaccid paralysis and LMN signs.
107
Werdnig Hoffman (SMA)
- Death to LMN in anterior horn. SNM gene, AR. - Floppy baby and dead by 7 months is classic presentation. There can also be a gradient to minimal clinical significance
108
ALS
- Destruction to upper and lmn. Leads to pure motor signs. - Genetic predisposition with superoxide dismutase mutation. Decrease in glutamate may aid in slowing progression - Generally starts with fasiculations in hands and tongues (can involve cranial nerves). Doesn't involve CNS or cognition. Also doesn't involve sensory. - Die because of respiratory collapse
109
MS
- Disseminated in time and space. Involves death of white matter (oligodendrocytes) T cells (CD4 and 8), Macrophages, and oligoclonal bands will be present. - Generally first seen with optic disturbances. - Worse with heat
110
Tabes Dorsalis
- Tertiery syphilis, causes destruction of DCML sensory neurons and tracts. - Loss of proprioception. Also loss of DTRs. - Tertiary syphilis will also have argyll robertson pupil: will accomadate but not react to light. - Painful charcot joints because of loss of position sense (GTO) - Sensory Ataxia with positive rhomber sign.
111
Subacute Combined Degeneration
- Demylination of tracts due to B12, E, Copper deficnecy. Most commony pernicous anemia, can also be abetalipoproteinemia. - Initially presents with tingling (DMCL) sensory signs, will progress to cause weakness and ataxia (Motor and sensory signs as well as spinocerebellar)
112
Synringomyelia
- Cystic dilation of central canal - Causes loss of anterior white commisure and loss of pain and temerature at the level of the lesion - Can expand and involve motor first and the SANS (IML gray) - Seen in Chiari II
113
Anterior Spinal Artery Occlusion
- Commonly seen at watershed area of T8. ASA from vertebral above and Adamkewitcz from thoracic aorta below. In times of hypotension - Destruction of everything except DCML. Loss motor, P/T, Spinocerebellar
114
Freidrichs Ataxia
- Trinucleotide repeat in frataxin gene (Fe-S) in mitochondria. - Lateral Spinal tracts and cerebellum show signs. Loss of LMN, DCML, Cerebellar. - Signs other than neuro: Kyphoscoliosis, Pez Cavus - Causes Hypertrophic Cardiomyopathy which is most common cause of death. Also increased rates of DM2.
115
Brown Sequard
- Transection (Hemisection of cord) | - Know signs
116
Horners Syndrome
- SANS from hypothalamus, synapse into IML Gray from T1-L2/L3. Then synapse in superior cervical ganglion. Finally travel along blood vessels and synapse in eye. - Ipsilateral miosis, ptosis and anhydrosis. - Destruction anywhere along tract. PICA, Pancoast Tumor, transection, etc.
117
Reflexes
-S1, 2: Ankle Jerk -L3,4: Patella -C,6: Biceps C7,8: Triceps
118
Primative Reflexes Reemerge
Primative reflexes inhibited by intact frontal lobe. Damage to frontal lobe may allow them to reappear
119
Pons external anatomy
- Cerebellar Peduncle | - CN 5,6,7,8
120
Medulla External Anatomy and CN
-Pyramids and olives. CN 9-12 (11 is extension of cervical nerve)
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Midbrain
- CN4: Arises dorsally, decusates and moves venrally - CN3 - Superior and inferior colliculi
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Pineal Gland
- Secretes melatonin (circadian rythms - Superior colliculi: Conjugate gaze (vertical) - Inferior colliculi: Auditory connections - Prinaud syndrome is pineal tumor or dysgerminoma, appears calcified, may compres CN4 and superior colliculus leading to vertical conjugate damage or inabilty to look down and out
123
Stylopharyngeus
-Elevates palate for swallowing. Only derivative of 3rd arch muscle. CN 9 only muscle.
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Vagal Nuclei
- Solitarius: Visceral Sensory (Taste, Abdominal Distension, baroreceptors) - Ambiguus: Somatic motor (pharynx, larynx, upper esophagus) - Dorsal Motor: PANS motor
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Optic Canal Contains
-Optic nerve, central retinal artery (opthalmic artery)
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Superior Orbital Fissure
-CN 3, 4, V1, 6, retinal vein, sympathetics
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Rotundum
-V2
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Ovale
-V3
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Spinosum
-Middle meningeal (Branch maxillary)
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Cavernous Sinus
- Internal Carotid artery in bony cage with 3,4,v1, v2, 6, and SANS. Lateral to pituitary - Cavernous sinus syndrome from mass effect (fistula, thrombosis, anyeurism) leads to fixed pupil, with loss of sensation from V1 and V2. Vision is normal. - Common site of skin bacterial spread (Staph, Strep)
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CN Testing
-V: Jaw toward lesion -7: Loss of blink reflex, lacrimation and facial expression -10: uvula away from lesion -11: Drop on ipsilateral side, can't turn head to contralateral side -12: Tongue deviates toward lesion
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Hearing Loss
Conductive: Can hear through bone but not air Sensoneurial: Can't hear anything through effected ear (Usually lesion of nerve.) Central lesion will usually only present with diminished hearing. -MS pts commonly have impaired hearing. -Presbicusis: Long term damage to base of organ of corti loss of high frequency sound. -Rupture of typmanic membrane is acute muffled hearing.
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Facial Nerve Lesions
- UMN lesion will result in paralysis of contralateral lower face. Upper face recieves dual UMN supply. Can occur from infarction of Genu of internal capsule - LMN Lesion is ipsilateral loss of all face motion and associated PANS. - Temporary (Bells Palsy Seen in many diseases): Lyme, HIV, VZV, HSV, DM.
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Mastication
- From branchial arch 1 innervated by V3 - Temporalis, Masseter, and medial pterygoid close. - Lateral pterygoid opens.
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Glaucoma (open angle)
- Increased introcular pressure leads to compression and ischemia of retinal artery. - Increased production (b2 adrenergic) or decreased drainage through canal of schlemm - Begins with tunnel vision, cells far away from central retinal artery become ischemic first. - Optic disc atrophy and increased cupping. Increased cup to disc ratio. - May be secondary to corticosteroids, vascular proliferation, uveitis.
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Closed angle glaucoma
- Lens presses against iris and obstructs flow. - Chronic closure has similiar presentation to open angle - Acute closure is emergency with painful sudden vision loss, headache, halos around lights. - Treat with pilocarpine to constrict ciliary muscle and open the angle. Never give epinephrine as this can exacerbte the closure
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Treatment of Glaucoma
- alpha 2 agonists (presynaptic receptor) decreases production of aqueos humor. Epinephrine, brimonidine. Blurry vision and myadryasis. - Beta blockers (timolol, betaxolol, carteolol) decrease aqueos humor production. - Acetazolamide inhibits carbonic anhydrase and decreases aqueous humor production - Cholinomimetics (pilocarpine, carbachol): contract ciliary muscle, open angle and meshwork. Use pilocarpine in emergencies. Causes miosis and spasm of ciliary muscle - PGF analogs (latanoprost): increase outflow.
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Cataract
- Opacification of lens, lens, lens - Neonatal: Rubella, CMV, galactosemia, galactokinase deficency. - Diabetes: sorbitol trapping - Steriods, sun exposure
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Papilledema
- Optic disk swelling: increased ICP. | - increased blind spot, blurred margins of optic disc
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Miosis and control
- Constriction of constrictor pupillae. CN3 - Ed west to ciliary ganglion 1st order - 2nd order is short ciliary to pupillary sphincter
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Mydrasis and control
- 1st order Hypothalamus to ciliospinal budge (c8-t1) - 2nd order from T1 to superior cervical ganglion - 3rd Follows internal carotid through cavernous sinus to long ciliary nerves - constriction of dilator pupillae
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Light reflexes
-Light carried by CN2 to pretectal area where synapses bilaterally on ed west nucleus. Then out to eyes and short ciliary nerves. Bilateral
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Marcus Gunn Pupil (afferent pupillary defect)
-Damage to CN2 or retinal detachment. Constriction is decreased bilaterally when light is shone in effected pupil.
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CN 3 Damage
- Motor damaged by compromised blood flow due to vascular disease (Diabetes). Ptosis and down and out gaze - Posterior communicating artery anyeurism/uncal hernia effects PANS first (Blown pupil)
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Retinal Detachment
- Separation of neural retinal layer (outside) from pigmented layer (inside) - Results in lack of support and nourishment and death of neural cells/photoreceptors. - Trauma diabetes, inflammation - Increased risk in patients with myopia. Preceded by posterior vitreous detachment (curtain drawn down)
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Retinitis Pigmentosa
- Progressive loss of vision due to retinal epithelium or photoreceptor loss - Can be seen in profound Vitamin A Deficency
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Vitamin A deficency
- Malabsorption syndrome - Loss of night vision first (retinal) - Keratomalacia and destruction of eye
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Meyers loop
- Located in temporal lobe. MCA. | - Contralateral superior quadrantanopia
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Optic radiationn
- Located in parietal lobe | - Lesion results in contralateral inferior quadrantanopia
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PCA infarction
- Hemianopia with macular sparing | - Bilateral projections of macula
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Macular degeneration
- Degeneration of macula related to age - Changes in central vision (scomata), begining with distoritions and progessing to complete loss. - Dry: deposition of drusen, yellow material beneath retina. Antioxidants may delay progression - Wet: Rapid loss of vision due to choroidal neovascularization. Treat with VEGF inhibitor (Bevacizumab) or laser
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Diabetic Retinopathy
- Early nonproliferative phase characterized by death of pericytes. Minimal vision changes - Later proliferative phase leads to vascular proliferation and covering of retina. Predisposes to retinal detachment. - Anti VEGF or lasers can treat.
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Internuclear Opthalmoplegia
- MLF allows for communication between CN 3 and 6 for horizontal gaze. Imparied in demylinating diseases. - Abduction of one eye does not cause adduction of other. - Nystagmus in abducting eye (Equalize with non adducted eye). - If right MLF, when looking to the right there will be nystagmus in right eye beating to the left. - Presents with double vision. - Commonly caused by MS and stroke.
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Alzheimers
- Progressive dementia in elderly. Cortical atrophy, neuritic plaques and NF tangles. - Lesions present in the hippocampus first (Memory loss) and progress to the rest of brain - Clinical diagnosis confirmed at autopsy - Neuritic Plaques are extracellular accumulations of AB amyloid. Formed from APP on chromosome 21 (increased in downs). APP normally is a TM protein - NF tangles are intracellular accumulations of hyper-P Tau protein. Normal Tau stabalizes MT. Correlate with severity of disease. Tau protein stains with silver stain. - There will be a decrease in Ach levels from the nucleus of mynert - Diffuse cortical atrophy leads to increased risk of subdural hematomas and will also show hydrocephalus ex vacuo. - Patient will present with early signs of memory loss that progress to cognitive decline followed by personality changes and eventually coma and death - Beta amyloid may deposit in vessels leading to weakness and hemorrhagic stroke (amyloid angiopathy) - Increased risk with Tri 21 (APP) mutations in presenilin 1 and 2 (TM proteins), Apoe4 which increases AB amyloid - ApoE2 is protective
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Picks Disease
- Frontotemporal dementia - Early degeneration of the frontal and temporal lobes with sparing of parietal and occipital. - Leads to early personlity changes and cognitive decline. Later will present with movement abnormalities. - Round intracellular Tau aggregates (silver stain)
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Lewy Body dementia
- Creation of lewy bodies throughout the cortex. Lewy body is ubiquitinated alpha synuclein. - Patients will present with cognitive decline, memory loss, personality changes and hallucinations. - Decrease in Ach levels (cognition) precedes loss of DA levels (motor)
157
Prion Diseases
- CJD is disease of misfolded PRP. Folds into beta sheet PRP(sc) which will convert normal PrP(c) into beta form. Progressive and rapid mental decline with brain showing vaculolzation (spongiform encephalopathy) - Halmark of prion diseases is exagerated startle response with myoclonus - Mad cow disease - Fatal Familial Insomnia
158
Other Forms of dementia
- Vascular dementia is the second most common cause. Repeated vascular insults lead to widespread cortical dysfunction. Arises in the context of HTN, Diabetes, atherosclerosis, vasculitis - HIV: Activation of macrophages and microglia lead to neuronal cell loss and gliosis. - Syphilis - Vitamin Deficencies - Wilsons Disease - Normal Pressure Hydrocephalus (Wacky, Wobly, Wet)
159
Hereditry Hemorrhagic Telangectasia
- Absence of capillaries and direct veno-arterial connection. Prone to breakage and hemorrhage. Have duplication of lamina? - Most commonly present on lips and in nose (History of nose bleeds). - Most symptomatic in CNS where they cause hemorrhage, siezures, headache, etc.
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Multiple Sclerosis
- Autoimmune waxing and waning disease characterized by demylination in central and peripheral nervous system. - Plaques most commonly found periventricular and in corpus collosum but can occur anywhere. Seen on MRI - Destruction of oligodendrocytes and myelin sheaths. - Infiltrate with T cells and macrophages. Reactive gliosis follows. - Elevated CSF protein and oligoclonal IgG banding on lumbar puncture. - Most commonly effects women from 20-50 far from the equator. - Often initially present with complaints relating to vision including INO and diplopia/nystagmus. Bowel and bladder symptoms are also common. - Symptoms will be worsened with heat as heat slows the conduction of nerves. - Treatment: IFNB, Steroids during acute attack, natalizumab (Ig4 mab that prevents extravasation of T cells and macrophages). Muscarinic antagonists can be given for bladder incontinence and baclofen can be given for spacticity.
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Guillan Bare
- Autoimmune inflammation and demylination of peripheral nerves following infection (Campylobacter, CMV, Flu). Molecular mimicry. - Results in progessive, symetric ascending paralysis. May reach the diaphragm and autonomics causing respiratory distress and arrythmias. Sensation changes occur later in the disease. Usually spares pain and temperature. - Elevated CSF protein without and increase in cells (defining feature). May also show papilledema. - Decreased nerve conduction studies - Treatment is usually supportive. Can use plasmaphoresis and IVIG.
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Subacute Sclerosing Panencephalitis
- Caused by defective measles virus. Measles virus gets into neurons and glial cells but has defective membrane proteins. This prevents the virus from escaping. Will buildup in cells and cause lysis. - Inclusions occur in gray and white matter. - Measles virus usually occurs earlier (koplik spots and rash) - Negative stranded RNA paramyxovirus. - Presents with non-specific cortical signs.
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PML
- Reactivation of latent JC virus due to immunosupression. Most commonly seen in AIDS that are not compliant with meds, can also be seen in other immunocompromised states. - JC is polyomavirus (DS DNA) - Infects oligodendrocytes and glial cells. Reactivation causes death of these cells and demylination. - Rapidly progressive and fatal with disseminated lesions in brain.
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Acute disseminated encephalomyelitis
- Multifocal perivenular inflammation and deylination following infection (VZV, measles) can be after rabies and smallpox vaccination - Demylination. - Kids and adolescents. ~guillan bare for CNS
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Metachromatic Leukodystrophy
- AR lysosomal storage disorder caused by absence of arylsulfatase A - Leads to accumulation of sulfatides in oligodendrocytes leading to death and demylination. - Variable pentrance often initially presenting with peripheral motor signs progressing to central signs.
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Charcot Marie Tooth
- Group of inherited defects in mylein proteins or mitochondria that leads to demylination. (Can be AR/AD) - Most striking symptoms are loss of anterior peroneal muscles leading to pez cavus and foot drop. - Deep Peroneal Nerve is most effected - Also causes scoliosis - Decreased nerve conduction studies. - P/T spared, motor usaully goes first and sensory next. Impaired proprioception early
167
Krabbes Disease
- Loss of galactocerebrosidase - AR lysosomal storage disorder - Normal at birth but by 3-6 months progress to significant peripheral weakness and coma. fatal by 2 years. - Destruction of myelin sheath.
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Adrenoleukodystrophy
- X linked inability to process long chain FA in peroxisomes. - Variable penetrance from complete vegetative state to mild adrenal insufficency.
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Siezure
- Synchronous firing of neurons in a specific area of brain. - Normally inhibitory pathway exist to prevent synchronous firing. - Most commonly originate in temporal lobe - Kids: Febrile, Epilepsy, Trauma, infection, tumor - Adults: Tumor, Stroke, infection, trauma - Often begin with aura of smell or sensation
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Partial Siezures
- Effect only a single part of brain - Simple Partial: Patient remains consious - Complex partial: patient has impairment in concious, but not complete loss.
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Generalized Siezures
- Can be absence: no movement | - Myoclonic, tonic-clonic, Tonic, Atonic
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Epilepsy
-Recurrent siezures. Febrile don't count
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Status Epilepticus
- Loss of conciousness for 30+ mins. May or may not be siezing the whole time. - Treatment is benzos and is a medical emergency
174
Cluster Headache
- Unilateral headache that starts behind the eyeball. - Intense brief periods of pain that recur for 15 mins to 3 hrs. - Often accompanied by lacrimation, rhinorrhea. May induce horners syndrome - Tx: triptans (seretonin analog) and oxygen
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Trigeminal Neuralgia
-Intense pain carried by CNV. Similar presentation to cluster headache except shorter duration
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Tension Headache
- Bilateral - No aura or other associated symptoms - Stead pain for 30 mins-6hrs
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Migrane Headache
- Unilateral, often preceded by aura. Pulsating pain - Photophobia, phonophobia, nausea - Irritation of CNV, meninges, blood vessels - Causes release of substance P, CGRP (calcitonin related peptide, vasodilation), and vasoactive peptides - Abortive Therapy is triptans - Preventative therapy is propranolol or topiramate
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Peripheral Vertigo
- Caused by damage to inner ear (semicircular canals), Vestibular nerve infection, menieres disease. - Delayed nystagmus on positional testing with minimal other signs
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Menieres disease
- Endolymphatic hydrops. Caused by excessive fluid in inner ear - Vertigo, tinnitus, and hearing loss
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Central vertigo
- Damage to Brainstem (Vestibular nuclei in pons) or cerebellum - Positional testing will show immediate nystagmus that may occur in all directions - Associated symptoms such as ataxia, dysmetria, vommiting - Most common cause is a stroke, may also be tumor or infection.
181
Sturge Weber Syndrome
- Caused by a somatic mutation that disegulates blood vessel growth - Causes Port Wine stain along CN V1 (Cutaneous hemangiomas) and hemangiomas of leptomeninges causing various neurologic symptoms. - Commonly causes glaucoma, pheochromocytoma, siezures and other neural signs.
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Tuberous sclerosis
- AD mutation in TSG leading to many hamartomas throughout body - Most significant arise in CNS and give rise to focal and general neuro defecits. - Rhabdomyoma causing mitral regurg is also common. - Ash leaf spots, siezures and hamartomas
183
NF1
- AD mutation in protein regulating RAS leads to increase RAS activity and the growth of cutaneous neurofiromas - Skin, Eyes, Pheo, optic gliomas - Cafe Au Lait spots, lisch nodules (in eyes)
184
NF-2
- AD mutation in Merlin TSG. Contact mediated cell cycle supression. - Bilateral acoustic neuromas - May cause hearing loss, Facial paralysis, and CNV dysfunction
185
VHL
- Mutation in VHL gene which is a TSG that regulates HIF physiology. polycythemia possible complication. - Leads to cutaneous vascular proliferation. Hemangiomas. - Bilateral Renal Cell Carcinomas - Hemangiomas in Brain and cord, also pheo.
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Metastatic Brain Tumors
- Most commonly from Breast, Lung, and Kidney (RCC) | - Genrally metastasize to meninges or to grey-white junction
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Glioblastoma Multiforme
- Tumor in adults of astrocytes (GFAP) - Crosses midline, poor prognosis - Causes massive necrosis with pseudopalisading cells surrounding areas of necrosis - Also see endothelial proliferation
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Meningioma
- 2nd most common tumor in adults, from arachnoid cells - Benign and attached to dura, does not spread to parenchyma - May grow and compress parenchyma causing focal signs and siezures. - Biopsy shows whirling spindle cells with psamomma bodies and calcifications
189
Schwannoma
- Of schwan cells but occurs within the vault at the cerebellopontine angle - Bilateral seen in NF-2 - Hearing loss and tinitus, may compromise 5th CN. Rarely involves the 9th and 10th. Never involves 7th, strangley - S100 positive (Neural Crest Marker)
190
Oligodedroma
- Tumor of oligodendrocytes in white matter. Most commonly in frontal lobe - Usually causes focal symtoms (Siezures) - Cells appear like fried eggs and are often calcified.
191
Pilocytic Astrocytoma
- Most common brain tumor in kids (Below tentorium) - Astrocytes GFAP positive. - Benign with good prognosis. - Biopsy shows eosinophilic corkscrew shaped astrocytes called rosenthal fibers
192
Medulloblastoma
- From primative neuroectoderm granular cells - Small blue cell tumor that forms rosettes around neuritic processes. - Highly malignant but highly responsive to radiotherapy
193
Ependymoma
- Tumor of ependymal cells, usually occuring in the 4th ventricle - May cause hydrocephalus, - Poor prognosis - Biopsy will show cells forming rosettes around vessels - Seen in NF-2 - May cause seringomyelia
194
Hemangioblastoma
- Seen in VHL patients - Tumor of foamy cells that is highly vascularized - Commonly seen with retinal hemangiomas (proliferation of vessels in retina) - May cause secondary polycythemia due to elevated EPO.
195
Craniopharyngoma
- Tumor of surface ectoderm of rathkes pouch (will make anterior pituitary) - Commonly calcified and may cause bitemporal hemianopia
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Herniations
- Cingulate/subfalcine: may compress anterior cerebellar artery. Ischemia in frontal lobe - Uncal Herniation: Uncus is medial temporal lobe, transtentorial. Causes decordicate posturing (flexor), compression of third cranial nerve, compression of PCA leading to macular sparing visual field defects, duret hemorhages (of paramedian basilar). Contralateral hemiparesis. Damage to reticular formation leading to coma. - Tonsilar Herniation: Compression of brainstem and respiratory centers leads to coma and death. Increased risk with arnold chairi and ehlers danlos.
197
Moro Reflex
- Startle causes arms to be pulled toward chest. Hang on for life reflex - Disappears at 3-6 months
198
Palmar Grasp Reflex
-Disappears at 1-2 months
199
Babinski Sign
-Disappears in 12 months
200
Sword Reflex
Disappears 7-8 months
201
Progressive Supranuclear Palsy
- Pathology will show widespread subcortical neuronal loss with reactive gliosis. - Gaze disturbanes plus parkinsonian symptoms, Neck dystonia, slurring of speech
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Muscle Sensors
- GTO: Detects muscle tension and is involved in relaxation to overtension. Also involved in proprioception and fine control - Spindle afferents: Stretch receptors that tell about degree of stretch. Intrafusal fibers will adjust to maintain proper tension.
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