Master the board step 3

Neurology
Restless Legs Syndrome (RLS)
RLS often comes to the health care provider’s attention when the bed partner
comes in complaining of pain and bruises in the legs. The patient experiences
an uncomfortable feeling in the legs, which is relieved by movement.
RLS is associated with iron
deficiency.
Treat with pramipexole or ropinirole.
A man comes to the emergency department with weakness in his legs that has
been getting markedly worse over the last few days. He has weakness and loss of
deep tendon reflexes in the legs. He recalls an upper respiratory illness about 2–4
weeks prior that resolved. What is the most urgent step?
a. Steroids
b. Intravenous immunoglobulins
c. Peak inspiratory pressure
d. Intubation
e. Lumbar puncture
Answer: C. This case is Guillain-Barré. Ascending weakness with loss of deep tendon
reflexes is characteristic. Peak inspiratory pressure is the correct answer. The peak inspiratory
pressure diminishes as the diaphragm is weakened. Peak inspiratory pressure
predicts who will have respiratory failure before it happens. This is the most important
factor in determining the need for therapy with either intravenous immunoglobulins
(IVIG) or plasmapheresis. Combinations of these medications are not effective. Steroids
are not effective. Lumbar puncture will show an elevated protein level with no cells.
Myasthenia Gravis
Myasthenia gravis presents with weakness of the muscles of mastication, making
it hard to finish meals. Blurry vision from diplopia results from the inability
to focus the eyes on a single target. The case may classically report drooping
of the eyelids as the day progresses.
Diagnostic Testing
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Best initial test: Anti-acetylcholine receptor antibodies (ACHR)
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Most accurate test: Clinical presentation and ACHR are more sensitive and
specific than an edrophonium or “Tensilon” stimulation test.
Treatment
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Best initial therapy: Pyridostigmine or neostigmine
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Thymectomy: Use in patients < 60 if pyridostigmine or neostigmine do not
work.
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Prednisone: If thymectomy does not work, or if there simply is no response
to pyridostigmine or neostigmine.
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Azathioprine and cyclosporine are used to try to keep the patient off of longterm
steroids.
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