Symptoms of Myasthenia Gravis

The hallmark of MG is painless, fluctuating or fatiguable muscle weakness. This means that with increasing muscle use, the muscles feel weaker and these symptoms may improve following rest. Symptoms may vary from day to day or even hour to hour, and typically gets worse as the day progresses. Several factors are known to worsen the severity of MG, and these include physical and emotional stress, coexisting infections, and certain drugs ( see Table 1).


The key symptoms that patients with MG present with include:

 ·   Muscle fatiguability and muscle weakness in the limbs (especially the proximal muscles)

 ·   Droopiness of the eyelids (referred to as ptosis) and double vision

 ·   Facial muscle weakness, slurring of speech and difficulty swallowing

 ·   Breathing difficulties


3.1 Fatiguable muscle weakness in the limbs

Both upper and lower limb muscles can be affected and tend to occur more in the proximal part of the limbs (eg the shoulder girdle muscles in the upper limbs and the thigh muscles in the lower limbs).

3.2  Droopy eyelids and double vision

Typically in many patients, the weakness starts with the eye muscles, with 60% of patients presenting with ocular symptoms of ptosis (drooping eyelids, often asymmetrical) or diplopia (double vision). Eventually, up to 90% of patients will demonstrate a degree of extraocular muscle weakness.

3.3  Facial muscular weakness and slurring of speech

 Myasthenia Gravis may affect the bulbar or throat muscles, presenting with symptoms like weakness of mouth closure, difficulties in chewing, a “snarling’ smile, nasal or slurred speech that can noticeably deteriorate as speech continues, impaired swallowing, reduced tongue movements and head droop related to neck weakness in 10% of the patients.

3.4  Breathing difficulties

 Breathing problems are rare, and affects only 1% as an initial presenting symptom, but this will require aggressive medical management as respiratory failure may occur rapidly.