A thorough physical examination in search of myasthenia gravis might reveal easy fatiguability, with the weakness improving after rest and worsening again on repeat of the testing for exertion. Though this is not often performed in medical examinations, when applying ice to the patient’s weak muscle groups, the weakness characteristically will improve (decrease). Additional tests are often performed in the search for myasthenia gravis, some of which are mentioned below. Additionally, a good response to medication can also be considered a sign of autoimmune pathology.

The hallmark of myasthenia gravis is muscle weakness that increases during periods of activity and improves particularly after periods of rest. The muscles that control eye and eyelid movement, chewing, talking, facial expression, and swallowing are particularly susceptible. The muscles that control neck and limb movements as well as breathing movements can also be affected. Often the physical examination is within normal limits, proving to be inadequate for diagnosis of myasthenia gravis, and as such, patients, especially children, may go for years without proper diagnosis of myasthenia gravis
The onset of the disorder myasthenia gravis might be sudden or rapid, and as such, often symptoms will come and go over time. The diagnosis of myasthenia gravis is initially and frequently often missed.

In most cases of myasthenia gravis, the first noticeable symptom that the patient displays will be weakness of the eye muscles. In other patients, primary symptoms to notice will be slurred speech and difficulty in swallowing, which also may be the first signs of the disease. The degree of muscle weakness involved in myasthenia gravis frequently varies greatly among patients, ranging from a localized form, limited to eye muscles (ocular myasthenia), to a more severe or generalized form where many muscles - sometimes including those that control breathing - are affected with weakness and straining. Symptoms of the disease, which vary in severity and type, may include an asymmetrical drooping of one or both eyelids (ptosis), double vision (diplopia) due to weakness of the muscles that control eye movements, and also possibly an unstable or waddling gait, as well as weakness in the arms, hands, fingers, legs, and neck, and also perhaps a change in facial expression. More symptoms may include difficulty swallowing (dysphagia), shortness of breath, and also impaired speech (dysarthria) often due to weakness of the pharyngeal muscles.
When paralysis of the respiratory muscles occurs, necessitating assisted ventilation to sustain the patient’s life, this is called myasthenic crisis. In patients whose respiratory muscles are already existing to be weak, myasthenia crises may be brought on, or triggered, by infection, fever, an adverse reaction to medication, or even emotional stress. Heart muscles are stimulated differently, and so therefore, the heart is not typically affected by myasthenia gravis.
Although myasthenia gravis is often hard to diagnose, knowing these hallmark symptoms may aid you in the search for identifying myasthenia gravis in your own child.