Internal-Medicine

Answers: 18–37 151
27. (D) This patient has trigeminal neuralgia.
Carbamazepine (an anticonvulsant drug) is
given in doses varying from 600 to 1200
mg/day. Phenytoin has also been used. The
two drugs can also be used in combination.
Operative procedures include alcohol injection
of the nerve or ganglion, partial section of the
nerve in the middle or posterior fossa, decompression
of the root, and medullary tractotomy.
Radiofrequency surgery can destroy pain fibers
but spare motor fibers. (Ropper, pp. 161–163)
28. (B) In central vertigo, the vertigo can be mild
and chronic. In peripheral disease, the symptoms
are generally more severe, but finite
(although often recurrent). (Ropper, p. 265)
29. (E) In myasthenia gravis, weakness of the facial
and levator palpebrae muscles produces a characteristic
expressionless face, with drooping of
the eyelids. Weakness of the ocular muscles
may cause paralysis or weakness of individual
muscles, paralysis of conjugate gaze, ophthalmoplegia,
or a pattern similar to internuclear
ophthalmoplegia. The presence of normal
pupillary responses to light and accommodation
with weakness of extraocular muscles, levators,
and orbicularis oculi is almost completely
diagnostic of myasthenia. (Ropper, pp. 1250–1251)
30. (A) Adenomas of the pituitary gland constitute
approximately 7% of intracranial tumors,
with the chromophobic type being the most
common. With macroadenomas, some degree
of pituitary insufficiency is common, and half
the patients have headaches. With microadenomas,
the other pituitary functions may be
completely normal. (Ropper, p. 575)
31. (A) The most common initial symptom of ALS
is weakness and wasting of the extremities.
The fasciculations can be a very prominent part
of the disease. This is rare in other neurologic
disorders. (Ropper, p. 939)
32. (C) The characteristic triad in Parkinson’s disease
(Tremor, Rigidity, Akinesia) has been
expanded to include Postural instability. This
forms the mnemonic TRAP. Autonomic instability
is also common. Findings on examination
also include masklike facies, dysarthria, stooped
posture, and abnormal gait. (Ropper, pp. 916–917)
33. (B) Tinnitus and deafness may be found in
peripheral vertigo, but not central. The nystagmus
is usually unidirectional and is never
vertical. Visual fixation inhibits vertigo and nystagmus
during testing in peripheral vertigo.
(Ropper, p. 260)
34. (A) Adults may develop hydrocephalus as a
result of occlusion of CSF pathways by tumors
in the third ventricle, brain stem, or posterior
fossa. In adults, the symptoms of obstructive
hydrocephalus include headache, lethargy,
malaise, incoordination, and weakness. Seizures
do not usually occur. Dementia, altered consciousness,
ocular nerve palsies, papilledema,
ataxia, or corticospinal tract signs may be present.
(Ropper, p. 535)
35. (B, D, F) Myelin is a complex protein lipid carbohydrate
structure, which forms part of the
cell membrane of the oligodendroglia. Vascular
lesions cause demyelination because of ischemia.
Papovaviruses can cause progressive multifocal
leukoencephalopathy in patients with HIV infection,
or less commonly, malignancy. Acute disseminated
encephalomyelitis has been described
after smallpox or rabies vaccination. Nutritional
deficiencies can also cause demyelination (e.g.,
pernicious anemia with vitamin B 12
deficiency).
(Ropper, p. 771)
36. (C) Pontine hemorrhage is associated with
impaired oculocephalic reflexes and small,
reactive pupils. It generally evolves over a few
minutes, usually with coma and quadriplegia.
The prognosis is poor, and death often occurs
within hours. (Ropper, p. 714)
37. (B) Cerebellar hemorrhage, when mild, may
present with only headache, vomiting, and
ataxia of gait. Patients may complain of dizziness
or vertigo. The eyes may be deviated to the
side opposite the hemorrhage. Nystagmus is
not common, but an ipsilateral sixth nerve palsy
can occur. This is the only type of intracerebral
hemorrhage that commonly benefits from surgical
intervention. (Ropper, p. 741)