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Principles of Neurological Diagnosis
1. Localization2. Etiology
Example 1 A 25 YO male, acute paraparesis
with urinary incontinence, severe LBP:
Localization: spinal cord Etiology: acute disc herniation
Example 2 A 75 YO female with diabetes and
HBP, sudden weakness of left side limbs
Localization: right hemisphere Etiology: intracerebral hemmorhage
Gross Anatomy of the CNS
Subsystems for this talk Motor system Sensory system Visual and ocular Blood supply
Motor system Lower motor neuron Upper motor neuron (origin of the corticospinal tract) Brainstem nuclei that project to the cord Basal ganglia Cerebellum Premotor frontal cortex Prefrontal cortex
Lower motor neuron Motor unit Fasciculation Weakness & atrophy Root – plexus – nerve
Upper motor neuron
Origin at prerolandic motor cortex
Humunculus, somato-topic arrangement
Posterior capsule Isolated movements
evoked by electrical stimulation
Paralysis due to UMN lesion
Weakness distribution (additional systems, crossed syndromes, sparing of midline bilateral muscles)
‘Classic UMN’ picture: spasticity, increased tendon reflexes, positive Babinski’s, (spinal shock)
Patterns of paralysis
Monoplegia without atrophy Monoplegia with atrophy Hemiplegia Paraplegia Tetraplegia
Cortico BulbarTract
Basal ganglia
Negative signs: hypokinesia, bradykinesia
Positive signs: involuntary movements
Extrapyramidal Clinico-Pathological Correlations
SymptomMorbid anatomy
Unilateral Rigidity + TremorContralat Substantia Nigra
Unilateral hemibalismusContralat subthalamic nuc (Luis)
choreaCaudate and putamen
Cerebellar dysfunction Incoordination – ataxia (dysmetria, dysdiadochokinesis) Intention tremor Dysarthria (slurred speech) Nystagmus Disordered gait and equilibrium
Sensory system
Skin or visceral sense organs Distribution by nerve, root,
CNS Primary afferent (DRG) Spinal tracts:
Dorsal columns Spinothalamic Spinocerebellar
Thalamus and cortex Descending analgesic tract
Dorsal Columns
Sensory dysfunction
Positive - paresthesia, pain, allodynia, hyperalgesia
Negative – hypesthesia, anesthesia, analgesia
Symptoms and Signs in Neurology
+-
MotorFasciculationInvoluntary Movement
Weakness paralysis
Hypotonia
SensoryParesthesia, pain, allodynia,
hyperalgesia
Hyp/anesthesiaHyp/analgesia
AutonomicHyperhydrosisDiarrhea
ImpotenceOrthostatism
Visual system Retina, optic nerve, chiasm, tract, radiation, cortex
Ocular movements
Blood supply
Circle of Willis
MRA of the Circle of Willis
Middle cerebral artery
Ant & Post Cerebral Arteries
Exercise I
30 YO man, weakness of right lower limbOn exam:Weak, spastic, hyper-reflexic right legLoss of touch on Rt legLoss of pain and temp. on Lt legHemi-Sensory level D8
Spino DorsalThalamic Columns
Exercise II
70 YO female, weakness of right side, speech difficulty
On exam: Rt hemiparesis Motor
dysphasia
Exercise III
60 YO male, Rt side weakness
On exam: Rt hemi-
paresis Lt facial
weakness