Objective: Myasthenia gravis(MG) is an acquired autoimmune disorder of neuromuscular junction. Prepubertal  children have a higher prevalence of ocular symptoms(OMG), lower frequency of acetylcholine receptor antibodies(AChR), and higher probability of achieving remission. We define presenting features and outcomes in our cohort.

Methods:  We identified four prepubertal children with MG.

Results:  Two males (M) and two females(F) with age of onset at  3(F1), 2.5(M1), 1.5(F2), and 10y(M2) were reviewed. All patients were tensilon test positive. They had electrophysiology, including the repetitive nerve stimulation(RNS) tests. All patients  had antibodies sent against AChR and Muscle specific Kinase(MuSK). Neuroimaging was done in three who presented with acute symptoms.

Three  children(F1,M1,F2)  presented acutely following  viral infections which included Chicken pox, diarrhoeal illness and  herpetic stomatitis respectively.  F1 presented with ptosis and bilateral divergent squint and was initially diagnosed with internuclear opthalmoplegia.  Months later was diagnosed with OMG following positive tensilon.  AChR antibodies are positive. Ptosis  resolved with pyridostigmine but the opthalmoplegia partially persists. F2 and M1 presented with ptosis and generalised weakness(M1). RNS showed a decrement in both. Both are antibody negative. Symptoms resolved with pyridostigmine in both.

M2 presented insidiously, is antibody positive and has a refractory course needing thymectomy, plasma exchange and rituximab.

Discussion: Could the relatively higher remission rates and lower levels of acetylcholine receptor antibodies seen in prepubertal  MG be related to a postinfectious autoimmune phenomenom? Or is there a genetic predisposition which is triggered by infection?  A high index of suspicion is necessary to make an early diagnosis.