Transcript Neurology - muhadharaty.com

• Cerebral
hemisphere
• Diencephalon
• Brain stem
• Spinal cord
Neurology
deals with the diagnosis and treatment of all categories of
disease involving the nervous system
which comprises 3 parts :
1) Central nervous systems
2) peripheral nervous systems
3) autonomic nervous systems,
Anatomy
What are the basic anatomical
components of the nervous system ?
Clinical features differences between UMN and LMN lesion ?
Upper motor neuron sign
== above ant. horn and
cranial nuclei
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No wasting
Weakness [UMN]
No Fasculation
Hypereflexia
Hypertonia [clasp knife
spasticity ]
lower motor neuron sign
== anterior horn or cranial
nerve nuclei and below
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Wasting
Weakness [LMN]
Fasculation
Hyporeflexia
Hypotonia
FUNCTIONAL ANATOMY
Types of cells includes:
1. Neurons
2. glial cells--- of 3 types
I.
Astrocytes
I.
II.
III.
structural framework
control the biochemical environment around the neuron
with the blood vessels forms the blood-brain barrier
II. Oligodendrocytes
I.
formation and maintenance of the myelin sheath] inside the CNS
III. Microglia[blood-derived mononuclear
macrophages]
3. ependymal cells lining the cerebral ventricles
Schwann cells : Peripheral neurons have axons invested in myelin
made by Schwann cells which line the nerve axon [ OUTSIDE PNS
Cerebral hemispheres
has four functionally specialised lobes
1.
2.
3.
4.
Frontal
parietal
Temporal
Occipital
 The brain stem
1.
2.
3.
midbrain
pons
medulla
oblengata
Brain stem
1-An important link between
spinal cord and higher brain
levels
2-relays motor and sensory
impulses between other
“higher” parts of the brain
and spinal cord
3-Midbrain – eye movement
control
4-Pons/Medulla Signal relay
Involuntary functions
Many cranial nerves
 Spinal cord : 31
different
segments
1. cervical
2. Thoracic [dorsal]
3. lumber
4. Sacral
5. coccygeal
The terminal portion of the spinal cord is called the conus medullaris
The cauda equina (“horse’s tail”) the collection of nerves root at the
end of the spinal cord
Gray Matter –masses of neurons + Absence of myelin
accounts for the gray matter of the brain – Cerebral Cortex
White Matter - Myelinated neurons gives neurons a white
appearance – inner layer of cerebrum
Physiology
Who does the nerve impulse take
place ?
THE GENERATION AND TRANSMISSION OF THE
NERVOUS IMPULSE
Nerve terminal
AXON
Synapse and
synaptic terminal
CELL BODY
Transmissions of information
between different part of nervous
system take place in 2 physiological
steps
1. conduction through the nerve
followed by
2. synaptic transmission
MYLEINE
AXON
• conduction [Nerve impulse] :
Electrical wave
conducted along the nerve leading to transmission of
information between neurons through generation and
propagation of an action potential
this is initiated by series of chemical transport of Na+ and
K+ across the neuronal cell
• Synaptic transmission : Entry of calcium causes
release of the neurotransmitter across the synaptic
cleft which binds to receptors on the post-synaptic
membrane which depolarize the membrane and
initiate an action potential in the postsynaptic
structure.
Neurotransmitter :are of
2 types
Excitatory
1-Acetylcholine
2-Noradrenaline/
3- adrenaline
4-Glutamate
5-Aspartate
6- 5-hydroxytryptamine
Inhibitory
1) Gamma-aminobutyric acid (GABA
2) Glycine
Te r m s
• Agnosia: faulty identification of recognition of an object
which cannot be explained by primary sensory deficit .
 Finger agnosia: :inability to identify and differentiate between his
fingers
 Astereognosia :inability to identify an object
by palpation
 Bilateral astereognosia = tactile agnosia
 Visual agnosia :inability to identify
an object by vision
 Apraxia :
loss of ability to execute previously
learned skills; in patients with normal
sensory , motor ,cerebellar and extra
pyramidal systems
Frontal lobe
Personality
Disinhibition
Emotional control
Lack of initiation
Antisocial behaviour
Social behavior
Contra lateral motor control
hemiplagia
Language[dominant lobe]
Expressive dysphasia[dominant lobe]
Incontinence
Micturition
Olfaction
Impaired smell[anosmia]
Apraxia of the left hand
Dominant
Parietal lobe :non dominant
Spatial orientation and Constructional skills
1. Apraxia[bilateral]
• Dominant
lobe
2. Tactile agnosia
• Non dominant
3. Agraphaesthesia
4. Gerstman syndrom
[Acalculia + agraphia+ Rt-Lt disorintation + finger agnosia ]
1) Constructional apraxia
2) Dressing apraxia
3) Neglect of contra lateral side [anasognosia]
4) Spatial disorientation
1. Focal sensory seizures
2. Contra lateral hemi sensory loss
3. Contra lateral homonymous
4. lower quadrantanopia
5. Asymmetry of OKN
Parietal: dominant:
- Language
- Calculation
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Dysphasia
Contralateral hemisensory loss
Focal sensory seizures
Dyscalculia
Astereognosis
Dyslexia
Agraphaesthesia
Apraxia
Contralateral homonymous
Agnosia
lower quadrantanopia
Asymmetry of optokinetic nystagmus
Temporal: dominant
= Auditory perception
=Language
= Verbal memory
= Smell
= Balance
Lesion leads to
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Receptive aphasia
Dyslexia
Amusia :non recognition of music
Impaired verbal memory
Contralateral homonymous upper quadrantanopia
Temporal: non-dominant Auditory perception
= Melody/pitch perception
= Non-verbal memory
= Smell
= Balance
Lesion leads to
•Impaired non-verbal memory
•Impaired musical skills (tonal perception)
• Contralateral homonymous upper quadrantanopia
Occipital
Visual processing
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Visual inattention
Visual loss
Visual agnosia [dominant]
Homonymous hemianopia (macular sparing)
Investigations :
• Electrophysiological

EEG[electroencephalogram]
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EMG [electromyography ]
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NCS [nerve conduction study]

evoked potential [visual , somatosensory ,brainstem audatory ]

IMAGING
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CT [computerized tomography]
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MRI [magmatic resonant tomography]
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SPECT or PET
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ultrasound (Doppler or duplex scanning)
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MR angiography MR venography

CT angiography
 Laboratory
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CSF
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Oligoclonal band
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IgG index

antibodies