(A738) The Diagnosis and Management of Laryngeal Myasthenia Gravis: A Systematic Review

Introduction: Isolated laryngeal myasthenia gravis (LGMG) is a rare manifestation of a usually systemic disease process. As such, LGMG is not widely studied and lack of awareness may preclude diagnosis. We aim to provide a systematic review of the existing literature on LGMG.

Methods: A systematic review of the literature pertaining to LGMG was conducted using Pubmed, Cochrane Library, Scopus, Web of Science, and CINAHL. Papers with unique data regarding LGMG were included. Isolated abstract screening followed by full-text review was performed to determine eligibility. The data extracted includes patient demographics, presentation, diagnoses, treatment, and outcomes.

Results: A total of 20 studies with 28 cases were included with most patients being female (52%). The average age at presentation was 50 years and the median time from presentation to diagnosis was 6 months. Common symptoms included dysphagia (n=16, 28%), dysphonia (n=15, 26%), dysarthria (n=9, 16%), dyspnea (n=6, 11%), and stridor (n=3, 5%). The most common laryngoscopy finding was impaired laryngeal movement (n=9, 47%). The most common diagnostic methods were anticholinesterase testing (n=9, 47%), serology (n=4, 21%), or both (n=4, 21%). Although 20% of patients were seronegative (n=3), the most detected antibodies were anti-AchR (n=11, 73%), and anti-LRP4 (n=1, 7%). Common treatments included pyridostigmine and immunosuppressants (n=10, 53%) and pyridostigmine alone (n=7, 35%). Of the treated patients, 100% experienced symptom improvement, and the majority experienced complete resolution (n=11, 55%).

Conclusions: LGMG is a rare manifestation with nonspecific laryngeal symptoms, resulting in a challenging diagnosis. Awareness is key to establishing a LGMG diagnosis. With proper identification, our review suggests that LGMG can be effectively managed with conventional therapies. Further study is needed to better characterize specific LGMG diagnostic criteria.