Internal-Medicine

Answers: 1–17 149
the patients. Other common initial presentations
include optic neuritis (25%) and acute myelitis.
Hemiplegia, seizures, and cervical myelopathy
(in older patients) occur occasionally as the initial
manifestation. Sphincter impairment usually
occurs later in the disease. (Ropper, p. 777)
9. (A) Posterior circulation TIA is suggested by the
transient episodes. The basilar artery is formed
by the two vertebral arteries and supplies the
pons, the midbrain, and the cerebellum. With
vertebrobasilar TIAs, tinnitus, vertigo, diplopia,
ataxia, hemiparesis, and bilateral visual impairment
are common findings. (Ropper, p. 692)
10. (E) The hemianopia is due to a lesion of the
left optic radiations. The posterior cerebral
artery arises from the basilar artery but is sometimes
a branch of the internal carotid. With posterior
cerebral artery lesions affecting the
occipital cortex, it is possible for the hemianopia
to be an isolated finding. (Ropper, p. 218)
11. (C) The two common forms of neurofibromatosis
(NF-1 and NF-2) are genetically distinct.
NF-1 is the type with multiple café au
lait spots and is associated with axillary or
inguinal freckling, iris hamartomas (Lisch nodules),
peripheral neurofibromas, and bony
abnormalities (including kyphoscoliosis).
NF-2 is associated with CNS tumors, particularly
bilateral eighth nerve tumors. Skin lesions
are spare or absent, and early lens opacities
can occur. (Ropper, p. 869)
12. (B) Huntington’s chorea is the most likely diagnosis
given the hereditary nature of this
patient’s illness (autosomal dominants). It differs
from Sydenham’s chorea by its gradual onset
and slow choreic movements versus brusque
jerks seen in Sydenham’s. The caudate nucleus
and putamen are both severely involved in
Huntington’s chorea, and degeneration of the
caudate nucleus results in enlarged lateral
ventricles (with a “butterfly” appearance on
CT). Atrophy is very widespread in the brain
and includes the cerebral cortex. A decrease in
glucose metabolism as revealed on positron
emission tomography (PET) scan precedes the
evidence of tissue loss. (Ropper, p. 911)
13. (B) Prophylactic administration of diazepam
in a withdrawing alcoholic can prevent or
reduce severe syndromes such as delirium
tremens (DTs). Prophylactic phenytoin, however,
is not helpful. A calm, quiet environment
with close observation and frequent reassurance
is very important. Vitamin administration
(especially thiamine) is important, but frequently,
severe magnesium depletion slows
improvement. (Ropper, pp. 1010–1011)
14. (C) Third nerve palsy can result in ptosis of the
eyelid. There is also loss of the ability to open
the eye, and the eyeball is deviated outward
and slightly downward. With complete lesions,
the pupil is dilated, does not react to light, and
loses the power of accommodation. In diabetes,
the pupil is often spared. The sixth cranial
nerve can also be affected by diabetes, but this
is much less common. (Ropper, p. 1135)
15. (D) This person has benign paroxysmal positional
vertigo (BPPV), which is characterized
by sudden-onset brief episodes of vertigo lasting
less than a minute. The symptoms are usually
brought on by head movement. The cause
is commonly attributed to calcium debris in
the semicircular canals, known as canalithiasis.
The debris is loose otoconia (calcium carbonate)
within the utricular sac. Although BPPV
can occur after head trauma, there is usually no
obvious precipitating factor. It generally abates
spontaneously and can be treated with vestibular
rehabilitation. (Ropper, p. 261)
16. (A) Injury to the ulnar nerve results in impaired
adduction and abduction of the fingers. The
nerve is commonly injured in elbow dislocations
and fractures. The fibers arise from the
eighth cervical and the first thoracic segments.
The ulnar is a mixed nerve with sensory supply
to the medial hand. (Ropper, p. 1168)
17. (D) This woman does not have risk factors for
sleep apnea (older age, snoring, obesity) and
likely has narcolepsy. Adrenergic stimulant
drugs such as methylphenidate or amphetamines
help the sleepiness, and tricyclic compounds
can help the cataplexy. Strategically
planned naps can also be helpful. (Ropper, p. 348)