Bulbar-Predominant Myasthenia Gravis Associated With Muscle-Specific Tyrosine Kinase Antibodies: A Diagnostic Challenge

Muscle-specific tyrosine kinase (MuSK) myasthenia gravis (MG) is an uncommon subtype of MG characterized by prominent bulbar and facial weakness with the potential for rapid progression and respiratory compromise.Patients are typically negative for acetylcholine receptor (AChR) antibodies, which may contribute to delayed recognition and diagnosis.We present a 20-year-old postpartum woman who developed a sore throat followed by progressive dysphagia shortly after an uncomplicated vaginal delivery.Persistent and worsening bulbar symptoms prompted further neuromuscular evaluation.AChR antibodies were negative, whereas MuSK antibodies were markedly elevated at 1934 U/mL, supporting the diagnosis of MuSK-positive MG with predominant bulbar involvement.This case highlights the importance of considering MuSK-MG in patients with unexplained progressive bulbar symptoms despite negative AChR antibody testing.Early recognition of this clinical phenotype and appropriate serologic testing are essential to facilitate timely diagnosis and treatment.