Myasthenia gravis is an autoimmune disease that primarily affects the neuromuscular junction, leading to abnormalities in acetylcholine receptors. This can cause weakness in some or all skeletal muscles, which easily fatigues, particularly after activity or exertion, with symptoms worsening. Symptoms can be alleviated after rest or treatment with cholinesterase inhibitors. As an autoimmune disease, myasthenia gravis often co-occurs with other autoimmune disorders such as hyperthyroidism, thyroiditis, systemic lupus erythematosus, and rheumatoid arthritis. Symptoms of myasthenia gravis typically lessen in the morning and worsen after activity, showing a pattern of being lighter in the morning and heavier in the evening.