[Pubmed] Laryngeal Myasthenia Gravis in Voice Patients: Clinical, Serologic, and Neuromuscular Characterization of Seron

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J Voice. 2024 Oct 16:S0892-1997(24)00331-X. doi: 10.1016/j.jvoice.2024.09.038. Online ahead of print.

ABSTRACT

OBJECTIVE: Laryngeal myasthenia gravis (MG) is a focal manifestation of MG, and most patients are seronegative for antibodies against the acetylcholine receptor (AChR) and muscle-specific kinase (MuSK). The purpose of this study was to determine the incidence of anti-AChR and anti-Musk antibodies in voice patients and to characterize the clinical and neuromuscular profiles of these patients in order to guide the diagnosis of laryngeal MG.

STUDY DESIGN: This was a retrospective case-control study that included patients over the age of 18 who underwent laryngeal electromyography (LEMG) as part of their evaluation for neuromuscular junction dysfunction.

METHODS: Cases and controls were evaluated serologically, for the anti-AChR, anti-MuSK, and anti-striational muscle antibodies, and neuromuscularly using the Tensilon test in some patients, repetitive nerve stimulation (RNS) test, and a treatment trial of pyridostigmine bromide. Cases were defined as either (1) positive anti-AChR or anti-MuSK, or (2) a positive Tensilon test or positive pyridostigmine bromide trial.

RESULTS: Two hundred and eleven patients were screened; 61 (29%) patients were identified with laryngeal MG, and 77 (36%) patients were selected as controls. All case and control patients were seronegative for the anti-AChR and anti-MuSK antibodies with no significant difference between case and control status for seropositivity for anti-striational muscle antibodies. Of the case patients with an electrically positive Tensilon test (80.6%) who completed a treatment trial, 100% had symptom improvement. Of the case patients with a symptomatically positive Tensilon test (16.1%), only 60% of patients had improvement with a treatment trial. The RNS was more likely to be positive in case patients than control patients, and cases had a higher severity of paresis in all laryngeal muscles with LEMG evaluation.

CONCLUSIONS: Laryngeal MG is an underrecognized condition in the otolaryngology community owing in part to its seronegative presentation. Electrical improvement with a Tensilon test, or electrical or substantial symptomatic improvement with pyridostigmine bromide represents the most robust diagnostic criteria in these patients.

PMID:39419706 | DOI:10.1016/j.jvoice.2024.09.038


Source: https://pubmed.ncbi.nlm.nih.gov/3941970 ... t9+e462414