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Weakness in the right arm
A 56 year-old man complained of weakness in the right arm. For 3 months prior to evaluation he had
been dropping objects from his right hand. He was unsure of the exact time of onset of symptoms, but
said that they were “getting worse.” There were no sensory abnormalities, difficulty with gait, or pain in
the neck, back, or head. On occasion he suffered cramps in the left thigh and calf. He had no bowel or
bladder dysfunction.
On examination, speech was slow and slurred. There was decreased muscle bulk in the right forearm,
with wasting of the interosseous muscles of the right hand. Tone was increased in the left arm and both
legs. Strength was moderately impaired in the right interossei, finger extensors, wrist dorsiflexors,
triceps, and deltoids. There was minimal weakness of the left arm. He could not walk on his heels or
toes and he had a subtle right foot drop. Fasciculations were noted in the right deltoid, right pectoralis
major, right calf and left quadriceps femoris. Reflexes were globally brisk, except for the right triceps
jerk. Babinski’s sign was present bilaterally. Sensation was normal.
1) Summarize the case briefly, including neuroanatomic localization and pathogenesis.
2) What is the most likely diagnosis? Name 1-2 alternative diagnoses, and discuss briefly why these
are less likely.
3) What additional information (history, exam, laboratory or other studies, consultations) would you
obtain? What laboratory findings would you expect if your most likely diagnosis is correct?
4) Assuming your most likely diagnosis is correct, how would you manage this patient? Include doses
for one medication you might prescribe, along with an estimate of the cost of a month of your
proposed therapy. How would you counsel the patient about his condition and about any proposed
therapy?) Summarize the case briefly, including neuroanatomic localization and pathogenesis.
2) What is the most likely diagnosis? Name 1-2 alternative diagnoses, and discuss briefly why these
are less likely.
3) What additional information (history, exam, laboratory or other studies, consultations) would you
obtain? What laboratory findings would you expect if your most likely diagnosis is correct?
4) Assuming your most likely diagnosis is correct, how would you manage this patient? Include doses
for one medication you might prescribe, along with an estimate of the cost of a month of your
proposed therapy. How would you counsel the patient about his condition and about any proposed
therapy?