Misdiagnosis Analysis of Myasthenia Gravis: Two Cases Report

Background Myasthenia gravis( MG) is an autoimmune disorder with predominantly neuromuscular junction involvement,the typical clinical manifestations were symptoms of muscle weakness,such as volatility and fatigability of skeletal muscles. Atypical MG can easily be misdiagnosed,thus the treatment is delayed. Objective To improve the understanding of atypical MG,so as to decrease the misdiagnosis rate. Methods The clinical manifestation,therapeutical and prognostic profile as well as misdiagnosis reasons of two MG patients were analyzed. Results Case 1,72- year old female,abrupt onset of multi- brainstem symptoms combined with positional vertigo and urination disorder,the case was diagnosed with progressive stroke for posterior circulation or high cervical spinal cord disorder initially. According to wide Jitter wave and conduction block of single fiber electromyography,chest CT suggests thymic hyperplasia,and immune therapy( pyridostigmine bromide and intravous immunoglobulin) was effective,the case was diagnosed with MG; case 2,27- year old male,suffered from multi- cranial nerve disorder including facial paresthenia,along with protein- cell separation in cerebrospinal fluid,the case was diagnosed with multiple cranial neuropathy more than once. According to seropositive RyR antibody and Titin antibody,wide Jitter wave and conduction block of single fiber electromyography,as well as chest CT and pathology suggest B3 type thymoma,the case was diagnosed with MG. Conclusion MG has diverse clinical manifestations except for myasthenia,clinicians should pay more attention to these,analysis of atypical clinical manifestations may enhance understanding of the pathogenesis of MG.