Week 4
12:30-1:30
DISORDERS OF VISION, HEARING, AND BALANCE
Case 1: A
63-year-old white male presented because he was unable
to see objects to his left. This became manifest when he
was sideswiped by a garbage truck in cross-traffic. On
examination he had a left homonymous hemianopsia to
confrontation, extending to the midline. Visual acuity
was normal. He showed "extinction" of tactile stimuli
applied simultaneously to his right and left hands
(i.e., he only reported stimulation of the right hand).
Otherwise, sensory and motor testing was normal. The
remaining neurological exam was negative.
1. What is the
course of fibers from retina to
occipital lobe?
2. What is the significance of the following
visual fields deficits: a) Homonymous
hemianopsia b) Heteronymous hemianopsia (such as
bitemporal hemianopsia) c) Homonymous superior quadrantanopsia d) Homonymous inferior quadrantanopsia
3. Occlusion of which vessel(s) may give homonymous
hemianopsia?
4. What is the significance of his extinction of
simultaneously applied sensory stimuli?
Case 2: A
33-year-old right-handed woman slowly lost hearing in
her left ear over a three-year period. There were no
other reported symptoms. Exam confirmed decreased acuity
to whisper on the left, with air conduction greater than
bone conduction bilaterally, and Weber lateralizing to
the right ear. There was gaze-evoked nystagmus on
looking to the left. The left corneal reflex was
diminished. A mild clumsiness and intention tremor were
noted in the left hand.
1. What is the differential diagnosis of hearing loss
in one ear?
2. What factors on exam or specialized testing might
distinguish cochlear from retro-cochlear lesions?
3. What is the localizing significance of the left hand
clumsiness and intention tremor?
4. What is the differential diagnosis in this woman?
Case 3: A
27-year-old woman developed progressive visual blurring
in her left eye and clumsiness in her right hand over
several days. Two years ago she had transient horizontal
diplopia. She has had a two-year history of fatigue,
heat intolerance and urinary urgency. On exam she has a
relative afferent pupillary defect on the left, a subtle
internuclear ophthalmoplegia (INO) on the right and
cerebellar ataxia in the right hand.
1. Localize the lesions and the physiology underlying
her afferent pupillary defect, INO, and ataxia.
2. Describe the differential diagnosis and the work-up.
3. Describe the
common signs and symptoms of multiple
sclerosis, its pathogenesis and treatment.
Case 4: A
55-year-old right-handed man awoke with severe nausea
and vomiting. He had previously been well, apart from
treated hypertension. When seen in the emergency room,
he preferred to lie on his left side, and became quite
ill when he rolled over. He denied other neurological
symptoms. On examination, he had a horizontal-torsional
nystagmus in primary position beating to the left (slow
phases to the right). This nystagmus was accentuated
when he looked to the left. He showed past-pointing to
the right and tended to fall to this side when he stood.
His hearing was mildly impaired bilaterally.
1. Localize the lesion in this man – is it due to a
peripheral (vestibular) or central lesion?
2. What is the differential diagnosis of acute vertigo:
at age 25? at age 65?
3. What other examinations and investigations could you
obtain on this patient?
4. How would you manage his problem?
5. What is the differential diagnosis of
posturally-induced vertigo?
6. What is the differential diagnosis of "dizziness”?
Extra Cases if Time Permits
Case 5: A
26-year-old right-handed woman complained of headache
and blurred vision for the past two weeks. There was no
history of underlying disease or head trauma. She was
very obese. Fundi showed bilateral papilledema. Her
acuity was 20/20 in both eyes, with her glasses. Visual
fields were full to confrontation except for enlargement
of her blind spot. Examination was otherwise negative,
except for difficulty in fully abducting either eye.
1. What is the definition of "papilledema" and what
is its differential diagnosis?
2. What is the possible significance of her difficulty
with eye abduction?
3. At the bedside, how does one test visual fields and
size of blind spots?
4. How does papilledema differ from optic neuritis and
ischemic optic neuropathy?
5. What is the differential diagnosis in this case?
Case 6: A
25-year-old RN suddenly notices that her left pupil is
larger than her right pupil (5 vs. 3 mm). She makes
inquiries of a third year clinical clerk, who is busy
pondering a laxative order.
1. What is the pathway mediating the
pupillary light
reflex?
2. What is the "near reflex" and its neuroanatomical
basis?
3. What is the differential diagnosis of
anisocoria?
4. What is
Horner's syndrome and what is it due to?
5. When does
anisocoria indicate that emergency measures
are required?
6. How can you
determine that self administered
atropine-like eye drops are the cause of anisocoria? |
