Incidence and Ocular Features of Pediatric Myasthenias

Abstract

Purpose: To report the incidence, demographics, and ocular findings of children with myasthenia Design: Retrospective cohort study Methods: The medical records of all children (< 19 years) examined at Mayo Clinic with any form of myasthenia from January 1 1966, through December 31, 2015, were retrospectively reviewed.Results: A total of 364 children were evaluated during the study period, of which 6 children were residents of the Olmsted County at the time of their diagnosis, yielding an annual age-and sex-adjusted incidence of 0.35 per 100,000 <19 years, or 1 in 285,714 <19 years. The incidence of juvenile myasthenia gravis (JMG) and congenital myasthenic syndrome (CMS) was 0.12 and 0.23 per 100,000, respectively. Of the 364 study children, 217 (59.6%) had JMG, 141 (38.7%) had CMS, and 6 (1.7%) had Lambert-Eaton syndrome, diagnosed at a median age of 13.5, 5.1, and 12.6 years, respectively. A majority of the JMG and CMS patients had ocular involvement (90.3 and 85.1% respectively), including ptosis and ocular movement deficits. Among children with at least one year of follow-up, (JMG; median, 7.1 years, CMS; median, 7.0 years) improvement was seen in 88.8% of JMG patients (complete remission in 31.3%) and in 58.3% of CMS patients. Conclusion:Although relatively rare, myasthenia gravis in children has two predominant forms, CMS and JMG, both of which commonly have ocular involvement. Improvement is more likely in children with the juvenile form.Myasthenia gravis is a chronic autoimmune disease characterized by fluctuating weakness and fatigability of the voluntary muscles of the body. 1 Pediatric myasthenia is a common term for disease onset prior to 19 years of age and includes both the autoimmune and inherited etiologies. 2 Pediatric myasthenia is divided into neonatal, congenital, and juvenile forms. Congenital myasthenic syndrome includes a diverse group of inherited disorders, typically present at birth, caused by a defective signal transmission at the neuromuscular

Management of Juvenile Myasthenia Gravis

“…In a long-term follow-up study in Denmark from 1996-2009, the incidence rate was 7 times higher in those aged 10–19 years compared to those aged 0–9 years (2.2/million v 0.3/million person-years) ( 3 ). The incidence in Olmstead county, USA, was determined as part of a larger cohort study as 1.2/million person years but this was only based on two confirmed cases ( 4 ). In contrast to these studies, a national study of AChR antibody positive MG from South Africa, estimated to account for 75% of cases, showed a higher incidence rate of 4.3/million person-years in those under 20 years ( 5 ).…”

The Epidemiology and Phenotypes of Ocular Manifestations in Childhood and Juvenile Myasthenia Gravis: A Review

“…A review from Thailand, but in juveniles (<15 years) presenting with ocular MG, also found limitations of EOM movement in more than 50% (of 62), and most had complete duction failure ( 29 ). Juvenile MG cases seen at the Mayo clinic (most were Caucasian children) found limitations of EOM movement in 30%, although there may be a bias to more severe cases in this cohort as most patients were not residents of the county ( 19 ).…”

“…A study from China found similar proportions of AChR-Abs by RIA and cell-based assay (CBA) in juveniles (<19 years of age) compared to adult-onset MG cases, although 18% of the juveniles (compared to 10% of adults) were only positive by CBA ( 31 ). The age-adjusted incidence rates of AChR-Ab positive MG among juveniles from South Africa ( 24 ) appeared to be higher than in Caucasian cohorts from the UK, USA, Norway, and Canada (≈3 per million vs. <1.5 per million, respectively) ( 12 , 19 , 32 , 33 ).…”

“…Although there is recognition worldwide of an increasing predominance of MG among the elderly, including in Asia and Africa ( 4 , 21 – 25 ), incidence rates among younger people manifesting with MG appear to differ between Asia and Europe. Population data including children are sparse and methodologies vary widely, but there appear to be four-fold higher incidence rates of MG among younger children from Asia compared to Europe and North America ( 12 , 19 , 26 ). A multiracial pediatric cohort from the United Kingdom (UK) in which data were accrued over 10 years showed similar findings with higher proportions of Afro-Caribbean, Asian, and Arabic children with MG compared to Caucasian children living in the UK ( 20 ).…”

Miastenia Gravis Okular Juvenil: Laporan Kasus

“…Insiden di daerah Olmstead Amerika Serikat, pada studi kohort yang lebih besar menunjukkan 1,2 juta orang per tahun tetapi hanya didasarkan pada 2 kasus yang dikonfirmasi (Mansukhani et al, 2019). Berbeda dengan studi ini, studi di Afrika Selatan dengan kasus antibodi AChR miastenia gravis positif diperkirakan mencakup 75% kasus, menunjukkan tingkat insiden yang lebih tinggi yaitu sebesar 4,3 juta orang per tahun pada mereka yang berusia di bawah 20 tahun (Mombaur et al, 2015).…”