clinical features

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The clinical features of myasthenia gravis are:

  • external ocular muscles - affected in over 90% of cases, and are the muscles first affected in 65% of cases; diplopia or ptosis, often asymmetrical, are typical; ocular myasthenia describes myasthenia confined to the eyes.

  • limb weakness - characteristically, increased by exercise, i.e. easily fatigued; shoulder girdle is commonly affected - patient may complain of difficulty in raising their arms above their head, or of brushing their hair; arm flexion is often more strong than extension; tone is normal and reflexes are often brisk; lower limbs are rarely affected; muscle wasting may occur in chronic disease.

  • bulbar - loss of facial expression - patient appears unable to smile and may seem to snarl; inability to whistle; dysarthria - often, slurring speech; difficulty in chewing and swallowing; weakness of the neck muscles may force the patient to sit with their jaw propped by a hand

  • respiratory - shortness of breath; may be exacerbated by lying down.

Last reviewed 06/2021