Principles of Neurological
Diagnosis
1. Localization
2. Etiology
Example 1
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A 25 YO male, acute paraparesis
with urinary incontinence, severe
LBP:
Localization: spinal cord
 Etiology: acute disc herniation
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Example 2

A 75 YO female with diabetes and
HBP, sudden weakness of left side
limbs
Localization: right hemisphere
 Etiology: intracerebral hemmorhage
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Gross
Anatomy
of
the
CNS
Subsystems for this talk
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Motor system
Sensory system
Visual and ocular
Blood supply
Motor system
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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
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Motor unit
Fasciculation
Weakness & atrophy
Root – plexus – nerve
Upper
motor
neuron
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Origin at prerolandic
motor cortex
Humunculus, somatotopic 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)
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Patterns of
paralysis
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Monoplegia without atrophy
Monoplegia with atrophy
Hemiplegia
Paraplegia
Tetraplegia
Cortico
Bulbar
Tract
Basal
ganglia
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Negative signs:
hypokinesia,
bradykinesia
Positive signs:
involuntary
movements
Extrapyramidal ClinicoPathological Correlations
Symptom
Morbid anatomy
Unilateral Rigidity + Tremor
Contralat Substantia Nigra
Unilateral hemibalismus
Contralat subthalamic nuc (Luis)
chorea
Caudate and putamen
Cerebellar dysfunction
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Incoordination – ataxia (dysmetria, dysdiadochokinesis)
Intention tremor
Dysarthria (slurred speech)
Nystagmus
Disordered gait and equilibrium
Sensory
system
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Skin or visceral sense organs
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Primary afferent (DRG)
Spinal tracts:
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Distribution by nerve, root,
CNS
Dorsal columns
Spinothalamic
Spinocerebellar
Thalamus and cortex
Descending analgesic tract
Dorsal
Columns
Sensory dysfunction

Positive - paresthesia, pain, allodynia,
hyperalgesia
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Negative – hypesthesia, anesthesia,
analgesia
Symptoms and Signs in
Neurology
+
-
Motor
Fasciculation
Involuntary
Movement
Weakness
paralysis
Hypotonia
Sensory
Paresthesia, pain,
allodynia,
hyperalgesia
Hyp/anesthesia
Hyp/analgesia
Autonomic
Hyperhydrosis
Diarrhea
Impotence
Orthostatism
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 limb
On exam:
Weak, spastic, hyperreflexic right leg
Loss of touch on Rt leg
Loss of pain and temp.
on Lt leg
Hemi-Sensory level D8
Spino
Thalamic
Dorsal
Columns
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Exercise II
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70 YO female,
weakness of
right side,
speech
difficulty
On exam:
Rt hemiparesis
Motor
dysphasia
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Exercise III
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60 YO male,
Rt side
weakness
On exam:
Rt hemiparesis
Lt facial
weakness
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