**3. Physical examination**

The physical examination should detect fatigable weakness in specific muscle groups by repetitive or sustained activity and also again after rest [1, 4].

Diplopia can be demonstrated by having the patient look laterally for about 30 seconds, leading to evident eye muscle fatigue [3]. The lid ptosis can improve by applying cold on the affected eye ("ice pack test"). Also, passively lifting a ptotic lid may cause the opposite lid to fall ("enhanced ptosis") [1]. Cogan's lid twitch—a pathognomic sign in MG—is described as the brief twitch seen in an eyelid that is elevated after rest [4, 5].

A useful functional test for dysarthria implies asking the patient to speak aloud without interruption producing nasality and/or hoarseness [6].

To test the limb muscle weakness, the patient should be asked to maintain for 3 minutes a horizontally stretched position of arms, hands, and fingers. In patients with MG, this test will lead to shaking or a gradual drooping of arms, hands, or fingers. Also, patients should be able to do knee bends or rise from a chair repeatedly without any support, 20 times.

Importantly, vital capacity and peak flow measurements should be assessed in all myasthenic patients [6].

## **4. Clinical classification**

Several scoring systems of myasthenic signs or the global state of the patient have been proposed including the Osserman classification, myasthenia gravis composite (MGC) scale, and quantitative myasthenia gravis (QMG) score [6]. However, currently the most widely accepted is the MG Foundation of America (MGFA) Clinical Classification which divides MG into five main classes and several subclasses [3, 5] as follows:

• **Class I**: Any ocular muscle weakness; may have weakness of eye closure. All other muscle strength is normal.

	- **IIa**. Predominantly affecting the limb, axial muscles, or both. May also have lesser involvement of oropharyngeal muscles.
	- **IIb**. Predominantly affecting the oropharyngeal, respiratory muscles, or both. May also have lesser or equal involvement of the limb, axial muscles, or both.
	- **IIIa**. Predominantly affecting the limb, axial muscles, or both. May also have lesser involvement of oropharyngeal muscles.
	- **IIIb**. Predominantly affecting the oropharyngeal and respiratory muscles or both. May also have lesser or equal involvement of the limb, axial muscles, or both.
	- **IVa**. Predominantly affecting the limb, axial muscles, or both. May also have lesser involvement of oropharyngeal muscles.
	- **IVb**. Predominantly affecting oropharyngeal, respiratory muscles, or both. May also have lesser or equal involvement of limb, axial muscles, or both.
