The goal of this observational study is to learn about the characteristics and prognostic outcomes of diaphragmatic ultrasound in myasthenia gravis. The main question it aims to answer is:

Does diaphragmatic ultrasound predict prognosis of myasthenia gravis in six months? Participants diagnosed as myasthenia gravis will take the diaphragm ultrasound examinations.

Inclusion Criteria:

• 1: Patients who seek treatment at the First Affiliated Hospital of Chongqing Medical University and have fluctuating skeletal muscle weakness and at least one of the following three conditions will be included: positive reaction to cholinesterase inhibitors

  2: Serum positive antibodies against acetylcholine receptors, muscle specific kinases, or lipoprotein related proteins

  3: Repeated electrical stimulation examination showed a decrease in wave amplitude.

Exclusion Criteria:

• 1: Patients with lung disease or heart failure, or a history of non-invasive ventilator or tracheotomy

Patients who seek treatment at the First Affiliated Hospital of Chongqing Medical University and have fluctuating skeletal muscle weakness and at least one of the following three conditions will be included: positive reaction to cholinesterase inhibitors; Serum positive antibodies against acetylcholine receptors, muscle specific kinases, or lipoprotein related proteins; Repeated electrical stimulation examination showed a decrease in wave amplitude.