Neuroanatomy
Meds IV
Shannon L Venance, MD PhD
Objectives:
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1.
2.
At the end of this session, provided
with a history and exam, participants
will be able:
Localize the lesion to the appropriate
part of the nervous system
Compare and contrast vascular with
demyelinating or neoplastic
presentations of brainstem lesions.
Case 1
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A 47 year old man presents with a decreased
level of consciousness (LOC).
 He complained of an sudden posterior
occipital headache with R face tingling and
drooping and then collapsed to knees(1130
hrs) while remaining alert.
 On route to hospital, seizure activity noted
and he was intubated on arrival to the
community ER and loaded with dilantin.
 He was transferred to Victoria Hospital as
there were no ICU beds available locally.
Case 1 continued…..
PMHx: brief episodes of vertigo,
dysarthria, collapsing (seconds to
minutes only) for 8 months; otherwise
healthy
 Med: ASA
 NKDA
 Soc Hx: married with 3 children

Case 1 24 hrs after presentation

hemodynamically stable
 intubated and fully ventilated, no sedating drugs
 unresponsive to voice
 no spontaneous eye opening
 pupils were pinpoint and reactive
 no horizontal eye movements with oculocephalic
maneuver (OCM)
 absent corneal reflexes, no response to nasal tickle
 weak gag, constant hiccoughing ~ 1-2/min
 tone was reduced with brisk withdrawal to noxious
stimuli in the legs bilaterally
 reflexes present, left > right; toes ↓↓
patient
normal
Case 1 48 hrs after presentation
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intubated, no breathing over the vent
pupils were fixed and dilated
no eye movements with OCM
corneals and nasal tickle absent
no gag, no hiccoughs
flaccid tone
no response to noxious stimuli all 4
extremities
reflexes left > right; toes ↑↑
http://www.med-ed.virginia.edu/courses/rad/headct/index.html
Case 2
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32 yo male presents with a 6 month history of
intermittent bifrontal headache with progressive
symptoms
3 months of intermittent diplopia on looking right or
left (no improvement with prism glasses)
headache became constant, associated with mild
nausea, worse in the mornings
2 months of right side weakness and incoordination
(dropping glasses, r leg buckling, falling to the right)
1 month right facial numbness
choking on liquids and had nasal regurgitation with
coffee, tea
symptoms worsened 1 week prior with a viral illness
and fever
Case 2

normal mental status
 pupils 8 mm OS and 6 mm OD, reactive, no APD
 restriction of right eye abduction with nystagmus
 vertical nystagmus on upgaze
 reduced pinprick right V1, V2, V3
 right lower motor neuron type facial palsy
 palate deviated to the right, tongue midline
 flaccid, hypophonic dysarthria
 right arm/leg spasticity with ankle clonus
 R>L hyperreflexia with extensor plantar response
bilaterally
 mild pyramidal weakness on the R
 dysmetria right > left
“control”
patient
Case 3
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Francois, a 48 yo right handed man woke this morning
with weakness involving the entire left side of his face.
Two days prior he noticed pain behind the left ear which
continues. His breakfast tasted “strange” this morning.
He has no other symptoms and he has otherwise been
well.
Your focused exam reveals normal tympanic
membranes, full extraocular movements, a left lower
motor neuron facial weakness (reduced forehead
wrinkling, eye closure and grimace) with a midline
tongue and palate. He hears sounds more loudly in his
left ear. No pronator drift. Deep tendon reflexes are 2+
symmetrical with flexor plantar responses.
Which of the following statements
about facial weakness is true?
A.
B.
C.
D.
E.
Ramsay-Hunt syndrome is a cranial nerve VII
palsy associated with lateral rectus paralysis.
Prednisone is the treatment of choice for Bell’s
palsy when started within 48 hours of onset.
Lower motor neuron facial palsy involves
paresis/paralysis of the lower facial quadrant
only.
There is no risk of recurrence with a Bell’s
palsy.
Cranial nerve nuclei located in the pons along
with the facial nucleus include CN III, IV and VI
Case 4
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53 yo woman develops sudden onset of left
sided weakness, right facial weakness and
double vision 2 weeks after an MI treated with
angioplasty
 PMHx also includes hypertension, stopped
smoking 2 weeks ago (prev 25 ppy hx)
 her medications include ASA, ramipril,
metoprolol and lipitor
Case 4
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abnormal eye movements on looking left
– right eye does not adduct but convergence is spared (right
eye adducts and pupil constricts)
– left eye abducts with left-beating nystagmus
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vertical eye movements are normal
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weakness of the right face including the forehead
weakness of the left arm and leg ~4/5 in a pyramidal
distribution
reflexes, L brisker than R with an upgoing L toe
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http://upload.wikimedia.org/wikipedia/en/thumb/b/b0/Internuclear_ophthalmoplegia.jpg/180px-Internuclear_ophthalmoplegia.jpg
Some pathology
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82 year old had been followed for many
years, on levodopa/carbidopa for a
degenerative process causing a rest tremor,
slowness and stiffness of movement, soft
voice with drooling and dysphagia; he had
been falling more recently
 died of complications after sustaining a hip
fracture from a fall
control
Parkinsonism
Case
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55 yo emaciated and dishevelled woman was found wandering
on the streets and brought to the ER on Christmas Day
she knew her name but was not oriented to date or time and
could not give her age or address but provided a rich story
which could not be corroborated
language was normal but she was unable to recall 3 items after
2 minutes; 5 minutes later she denied having seen you before;
otherwise reading, writing and higher mental functions were
normal
her neurologic exam was otherwise normal
while waiting for the neurology resident, she was given a tray of
holiday goodies which she devoured
No known medical history, medications, allergies
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on examination 2 hours later, she was slightly drowsy
but rousable, not oriented to month or year and
thought the resident was her boyfriend
she had nystagmus in all directions of gaze and her
gaze was dysconjugate when looking right or left
normal strength, reflexes 2+ except ankles 1+ and
her toes were upgoing bilaterally
mild reduction in vibration at the toes
she was unable to heel-shin bilaterally and her gait is
wide-based and markedly ataxic
http://medlib.med.utah.edu/WebPath/CNSHTML/CNS083.html
http://www.urmc.rochester.edu/neuroslides/slide157.html
Summary: clinical brainstem
CN III – XII symptoms and signs
 crossed sensory or motor findings
 coordination, ocular, vertigo
acute onset
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– abrupt is vascular; if over hours – toxic, metabolic
– if LOC, remember reticular activating system
(RAS) within brainstem is responsible for alertness
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chronic
– over weeks to months; neoplastic, demyelinating,
degenerative
http://www.meddean.luc.edu/lumen/MedEd/Images/NeuroLab/nl35sl.jpg
http://www.meddean.luc.edu/lumen/MedEd/Images/NeuroLab/nl35sl.jpg
http://www.meddean.luc.edu/lumen/MedEd/Images/NeuroLab/nl35sl.jpg
http://www.meddean.luc.edu/lumen/MedEd/Images/NeuroLab/nl35sl.jpg
Questions?