A 30-year-old female presents with diplopia and weakness
of her upper limbs that increases towards evening. On examination there is
demonstrable fatiguability, reflexes are normal. There is no sensory loss.
The patient is treated with pyridostigmine and there is
resolution of her symptoms. She subsequently presents with increasing weakness
that has begun to involve her limbs and she also has involvement of the
muscles of respiration. There are no fasiculations, pulse rate is 90 beats per
minute, pupils normal in size, equal and react to light and accommodation.
In this situation the best mode of treatment would be
with:
a)
Steroids
b)
Steroids and azathioprine
c)
Atropine
d)
Edrophonium
e)
Plasma exchange
Answer: e)
The clinical features suggest the patient has developed a
myasthenic crisis. There are no cholinergic features. In this life-threatening
situation plasma exchange is extremely helpful as an immediate measure. It is
thought to work by removing circulating acetylcholine receptor antibody
Revision Tip
Revise myasthenia gravis KEYS to
SUCCESS in Medicine page 478-480
