localising the lesion – where in the nervous system?
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Localising the lesion – where in the nervous system?. CRAIG HICKSON & Helga Magnusson. Aims and objectives. Definitions of the CNS & PNS To learn the signs associated with LMN and UMN Brief recap on the functions associated with different lobes Cortical representation of body parts - PowerPoint PPT PresentationTRANSCRIPT
Localising the lesion – where in the nervous system?
CRAIG HICKSON & HELGA MAGNUSSON
Aims and objectives
Definitions of the CNS & PNSTo learn the signs associated with LMN and UMNBrief recap on the functions associated with
different lobesCortical representation of body partsCircle of Willis and blood supply to each hemisphereMotor tracts – lateral corticospinalSensory – lateral spinothalamic & dorsal column
Clinic scenarios/Case vignettes
The central nervous system
‘The CNS consists of the ........ and the ....... .......
Some definitions include the ....... ....... and the retina
?
The peripheral nervous system
‘The PNS consists of the nerves and the ganglia outside of the brain and the spinal cord’
Includes autonomic NS and in most definitions the cranial nerves
Upper motor neuron signs
Spastic paralysisHypereflexiaHypertoniaNo muscle wasting – some wasting from lack of use eventually
Pyramidal weakness – flexion of upper limbs, extension of lower limbs
Positive Babinski – up-going plantar
?
Lower motor neuron signs
Flaccid paralysisHyporeflexiaHypotoniaMuscle wastingFasiculationsWeakness of muscle groups – mytomes
-ve Babinski?
Lobar function
Fontal – personality, executive function, cognition, & primary motor cortex. Left Frontal – Broca’s area
Parietal – primary sensory cortexOccipital – visionTemporal – hearing
Left Temporal – Wernicke’s area
Cerebellum – balance, co-ordinationBasal ganglia – initiation, inhibition of movement
Homonculus
Hands and face massively‘over represented’
More sensitive
Circle of Willis
Anterior cerebral artery
Middle cerebral artery
Posterior cerebral artery
Basilar artery
A = ?
B = ?
?Anterior spinal artery
Vertebral artery
Blood supply to the brain
The tracts
Dorsal column
Corticospinal
Spinothalamic
?
?
?
Spinothalamic
• Contra-lateral
• Cross at entry level pain and temp over 1 level touch over several
• Pain, Temperature, touch• ?
Dorsal Column
• Contra-lateral
• Cross at Medulla
• Vibration, propriaception Discriminative touch• ?
Corticospinal
• Motor tracts
• Contra-lateral
• Cross at Medulla
How to think
UMN or LMN signs?LMN: peripheral nerve/neuromuscular
junction/muscular.UMN: cerebral (?lobe), cerebellar, spinal cord
(?tract)Can the symptoms be explained by one
lesion?Differential diagnosis:
Immediate: vascular. Intermediate: inflammation/infection/malignancy. Long term: degenerative/malignancy.
Cases
• 57 year old man complaining of weakness and altered sensation in upper limbs and lower limbs
• Loss of sensation from shoulders and down, urinary incontinence
• ON Examination• CN intact• Upper limbs weakness, hypotonia, reduced
reflexes• Lower limbs spasticity, hyper-reflexia and
Babinski +ve, reduced sensation from shoulders down
What could have caused this picture?
Cases
• 85 year old man with long standing (20yr) history of balance problems worse in the dark.
• Gait is high stepping• ON Examination• CN intact• Motor intact• Loss of propriaception with +ve romberg
What could have caused this picture?
Cases
• 35 year old lady who cant feel hot water when she puts her hand in the bath anymore
• ON Examination• Sensation – pain and temp reduced in upper
limbs• Light touch and propriaception retained
What could have caused this picture?
Cases
• 42 year old lady complaining of unsteadiness of balance and slurred speech, she has noticed weakness and loss of sensation in her left leg
• Leg symptoms have been present for two months• Unsteadiness and slurred speech came on over last 10
days• On examination:• CN intact• Weakness left lower limb 4/5• Hyper-reflexia – left leg only• Coordination impaired on left• Mental state NAD
What could have caused this picture?
Thankyou for listening and contributing
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