Juvenile Myasthenia Gravis

A child previously healthy, presented to the ED with his mother for new onset right upper eyelid ptosis of few weeks duration. History was significant for variability in eye alignment over the past few months. Exam was notable for right upper eyelid ptosis with MRD1 of -2 and poor levator function. There was also elevation deficit in the right eye, however other extraocular movement were normal. VA was equal in both eyes. Pupils were equal and reactive with no APD. Anterior and posterior segment exams were within normal limits. MRI/MRA of brain and orbit with and without contrast were ordered and confirmed to be negative for any intra-cranial pathology. On follow up visit, exam was noticeable for new onset bilateral abduction deficit, old pictures were also obtained from a family member which showed bilateral upper eyelid ptosis. Patient was then referred to neurology service for myasthenia gravis work up. Lab tests came back positive for Acetylcholine Receptor Binding Antibody= 7.45 (high), Acetylcholine Receptor Modulating Ab =72 (high), her Acetylcholine Receptor Blocking Antibody<15, MuSK Interpretation: negative. Genetic testing for congenital MG was negative. The patient was diagnosed with Juvenile onset Myasthenia Gravis disease and was started on pyridostigmine. Her symptoms improved initially with pyridostigmine and prednisone but recurred a few weeks later. The patient started developing bulbar and respiratory symptoms requiring intensive care treatment, in addition to worsening of extraocular movement including bilateral ptosis obscuring the visual axis. Rituximab was then added leading to gradual improvement in the patient’s symptoms and eventual resolution of ocular symptoms as well.

Presentation Date: 12/09/2021

Issue Date: 01/07/2022