Where+is+the+Lesion

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=I. Sample Localization Problems= =II. The Game= =III. The Rules= =IV. The Play= =V. The Play, Abbreviated= =VI. Rules for Speed Play=

=Reading= >>III.1-III.8 >>III.24-25 >>I.19-20 >>III.27-III.39 >>II.40 >>II.3 >>II.34 >>II.59-60 >>II.18-II.19 >>III.77-78
 * Online Exercise
 * High-Yield, chapters 6-9,**14**, 20, 23, 24
 * Gelb, chapters 1-3
 * Coursepack
 * Neuroanatomy through clinical cases
 * Neuroanatomy Text & Atlas
 * Previous coursepack, Limbic System & Cerebral Hemispheres
 * Netters

Speed Play JGems: Hypoactgive reflexes indicate dysfunction in the peripheral portion of the reflex arc. A hyperactive reflex indicates a leasion in the central pathway suppressing the peripheral refex arc. Anterior ot the optic chiasm, a structural lesion will affect vision from only one eye. A focal lesion in the middle fothe chiasm will cause bitemporal hemianopia

The parasympathetic pupillary reflex runs through the optic chiasm, then diverges to synapse in the dorsal midrain with parasyapthetic nerve fibers that run wtih the oculormotor nerve to ennervate the pupillary constrictor muscles. Note that even with input to just one eye, both pupils will constrict.

The sympathetic pupillary ennervation runs from the hypathalamus down throught he spinal cord to the T1 level, then enters the sympathetic chain and synapses at the superior cervical ganglion. I tthen follows the internal carotid artery, then the ophthalmic division of the trigeminal nerve, ultimately terminating in the pupil. It remains on one side of the nervous system for its entire course.

Brown-Sequard Syndrome: > Partial: asymetric paresis with hypalgesia more pronounced on the less paretic side. > Pure: >> Interruption of Lateral Corticospinal Tracts >>> Ipsilateral spastic paralysis below lesion >>> Ipsilateral Babinski sign >>> May not be present in acute injury >> Interruption of posterior white column: loss of position, vibration, and fine touch sensation below lesion >> Interruption of lateral spinothalamic tract: Contralateral loss of pain and temperature sensation 2-3 levels below the lesion

1.) If both strength and pain/tempearature sensation are imparied in a single imb, the lesion is either peripheral * nere/pleus/root) or in the cortex (the pain pathway croses low in spinal cord; the motor wapthay crossses high in the medulla; the lesion must be below crossing or above medulla)

2.) Reduced paintemperature on one side and reduced positon//vibration on the other side, the lesion is in the spinal cord on the same side as the position/vibration deficit (Brown-Sequard Syndrome)

3. Bilateral sensory and motor deficites throughout the body below a roughly horizontal level on the trunk, with normal functionabove, indicate a spinal cord lesion

4. Increased reflexes in a symptomatic limb suggest a central lesion; reduced reflexes in a symptomatic limb suggest a peripheral lesion

5. Reduced pain/sensation on one side of the face and the ppositte side of the body implies a lesion between the pons and C2, ipsilateral to the facial numbness. Reducedpainemperature on one side of the face and the same side of the body implies a lesion in thee high brainstem or above facial pain wathway enters pons via trigeminal enevrve, descends to about C2, crosses, ascends on opposite side descending pathway from pons to C2 is close to the contralateral body after crossing at C2 level, the tract converying facial sensation is ipsilateral to trunk and limb sensation, but the two are nt lcose until the high brainstem

6.) Ipsilateral facial and body weakness implies a lesion in high pons or above

7. Both 3rd nerve palsy and Horner's syndrome can resolt in ptosis and puillary asymetry; but with 3rd nerve palsy, the ptosis is on the side with the large pupil, but wth Horner's syndrome the ptosis is on the side of the small pupil

8. Diplopia is always due to a lesion in brainstem or periphery, but not cortex. A gaze palsu (imparied movement of eyes in one direction, bout both eyes move congruently and stay aligned in all positions o gaze) is due to lesion in cortex or brainstem but not periphery.

9. Visal symtoms in only one eye imply lesion anterior to chiasm

10. Aphasia or dysphasia implies lesion in dominant cerebral hemisphere. Disarthria in absense of dysphasia suggests subcortical, brainstem, or cerebellar lesion

11. An ltered level of consciousness indicats either a brainstem lesion or bilateral disfunction of cerebral hemispheres. 2.)

=Goals=

3. Know how to interpret abormalties on the nurological exam
=4. Know how to use localization and time course to deduce the likely disease category==

Know attention and neglect: phenomena, hemispheric dominance
==8. Know memory: Episodic, semantic, cprocedural working memory; papez c ciruit)

9. Know common mechaisms of brain injury and death: Oxidative stress, excitotxicity, encrosis, apoptosis, gliosis, protin sequestration, expanded trinlceotide repeats)
nervous system each sx/sign corresponds to a line segment: CNS &lt;--&gt; Periphery &gt; May still find pattern: all peripheral nerve, all proximal/distal, and motor/sensory....
 * If all line segments intersect at a sngle point, that's the lesion
 * if more than one such point, must differentiate
 * if no single point, look for two
 * if still unsuccessful, look for a pattern

still possible that there are two lesions rather than one... Where does it cross? often will reduce the possible locations of lesions

Pain/Tempearature(limb)

 * Spinothalamic Tract (Anterolateral system)
 * Crosses within 2 segments, prjects to thalamus and psot central gyjrs

Strength(limb)

 * Corticospinal tract
 * Crosses at level of Medulla

//Can usually ignore crossectional detail//

Position/Vibtration pathway ==Medial lemniscus tract

Face: Facial Sensation Slightly more complicated Comes in left side, enters pons: 5th cranial nerves goes down to spinal cord crosses over then crosses over and goes up

Face: Strength Corticobulbar Tract Crossin high pons, also uncrossed pathway for forehead muscles of bottom 2/3 of face...

If have stroke in left cortex, lose all cells going to right facial nerve nucleus going to take out all central input to bottom 2/3 of face but top part of face willstill have

Pupillary constriction to light optic nerve/tract--&gt; Bilateral oculootor nerve Pupillary dilatation Sympathetic nervous sytem

details of where pathway runs

pupillary pathway... starts in hypothalamus, goes down to high thoracic cord onto sympathetic trunk ascends to carotid artery

at level of brainstem, left lateral rectus moves right nerve... but at level of brain...both sides have connections to brainstem

reflexes pathway for DTR gaze center concerned which direction eyes are moving

loss of hearing loss of

point: assymmetric pupils pa-1650-05D

can't tell immediately from looking

Can approach neurological diseases in a systematic way

=Apporach to neuro diagnosis=

Localization
need to stick with it

Time Course
Acute Subacute chronic transient/recurrent/episodic

Demographic Factors
Diabetes, alchoholism, family hx

system:
 * || Acute: static||Acute: progressive||Subacute||chronic||
 * focal||-vascular (sischemic), trauma||vascular (hemorrhage), trauma||inflammatory (absess)||neoplasm||
 * diffuse||toxic/metabolic, trauma (concussion)|| vascular (SAH) trauma (SAH) toxic/metabolic||inflammatory (meningitis), toxic/metabolic||degenerative||

Definitions Localization Temporal Profile Epidemiology Etiology > Degenerative Diseases > Neoplastic Diseasess > Vascular DIseases > Inflammatory diseases > Toxic and metabolic diseases > Traumatic diseases > Congenital disesaes

=localization, part 2= =common themes in neuro disease=

trauma hx may not always be evident

//example: Numbness and weakness in feet past 2 days; gradually progressing up LEs. Exam: Weakness both LEs, wrose L; flexores worse than extensors, proximal = distal reduced pain/temp sense in right leg decreased vibration position sensation left LE L LE hyperreflexia and L Babinski//

Numbness, weakness in feet 2 days areflexea both UEs, normal strength, senssation

weakness both LEs, worse distally, R=L reflexia areflexia

Guillan-Barre won't get to exact diagnosis

vascular lesion rarely infarcts one nerve

Focal: TIA migraine Seixure

Hypoperfusion Migraine Seizure Metabolic

Localization, part 2
Easy stuff: senssation, limbs, vision, audtiion, oflaction, taste...movement, speech, swallowing, eyemovements, autonoic functions

Hard stuff: language, memory, attention, consciousness

if deviate, fix it control system thermostats deep tendon reflex mathcing motor neuronf iring rate to joint position

pre-frontal cortex: mathcing immediate goal to long-term goal

lesion of frontal lobes: keep doing something long past point where no longer useful

frontal lobes... allow to process what are main goals which information going to pay attention to

never finishes task seems like opposite of perseveration.... perseveration &amp; persistance not keeping goal-oriented

ascending levels of control conscious/unconscious