brain stem lessions in sensory symptoms
Post on 08-Jul-2015
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HOW TO
LOCALISE
BRAIN STEM
LESIONS WITH
SENSORY
SYMPTOMS????
THE CURIOUS CASE OF A 62 YEAR OLD DRIVER…
H/o sudden onset of
unsteadiness of gait,tendency to fall
to right side
C/o loss of sensation in the rt half
of face & left hemitorso,dysphagia.
O/e partial
ptosis,enophthalmos, miosis of right
eye.
Cerebellar signs present
No motor loss.
ANATOMY OF BRAIN STEM
LOCALISATION OF THE LESION IS BY OBSERVING THE COMPANY THEY KEEP…
A midbrain
lesion: CN III
: ptosis, dilated
pupil, eye down and
out
: vertical gaze palsy
A lesion of the pons: CN 6 or 7
(this is a LOWER motor neurone type
lesion)
: Horizontal gaze palsy
: Unilateral facial numbness from CN 5
(results in CROSSED SENSORY
LOSS)
: Unilateral deafness
A lesion of the
medulla: bulbar palsy
: Unilateral facial numbness from
CN V
(Descending spinal tract and
nucleus)
Nystagmus :
medullo-pontine
junction.
MEDIAL LESIONS
Medial Lemniscus:
contralateral loss of vibration and
proprioception in the arm and leg
Medial longitudinal fasciculus:
ipsilateral inter-nuclear
ophthalmoplegia
Motor cranial nerve nuclei
LATERAL LESIONS
Sensory pathways.
Motor cranial nerve nuclei.
Cerebellar peduncles.
• Ataxic tremorsuperior
• General clumsinessmiddle
• Motor adaptation impaired.inferior
ptosis
BACK TO THE CASE…
Cross section of
medulla
WALLENBERGS
SYNDROME/ LATERAL
MEDULLARY SYNDROME
VENTRAL LESIONS
Descending corticospinal
pathways
LOW MEDULLARY LESIONS
Bilaterl or ipsilateral
weakness/sensory disturbance.
Main pathways decussate at this
level.
BALACLAVA HELMET DISTRIBUTION
Trigeminal sensory
fibres
Back of face-descend
more
More forward areas
of face- descend
shorter distance
MULTIPLE SCLEROSIS
Resemble trigeminal neuralgia
CEREBELLAR INVOLVEMENT
Unsteadiness of gait
Intention tremor
Nystagmus on attempted
lateral gaze
FALSE LOCALISATION SIGNS
Increased ICT – 6th CN palsy
Third nerve palsy
Tentorial herniation.
Posterior communicating
artery aneurysm
Thank you!!!
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