Clinical Characteristics of Pediatric Myasthenia: A Surveillance Study

Abstract

OBJECTIVE: To evaluate the incidence, clinical features, diagnostic, and treatment trends of pediatric myasthenia in Canada. METHODS: Through established Canadian Pediatric Surveillance Program methodology, physicians were anonymously surveyed for cases of pediatric myasthenia using a standardized clinical questionnaire containing deidentified data. Inclusion criteria were any child <18 years old with ≥1 of the following: (1) fluctuating ptosis or extraocular weakness, (2) skeletal muscle weakness or fatigue, and (3) any of the following supportive tests: clinical response to acetylcholinesterase inhibitor, positive antibodies, abnormal slow repetitive nerve stimulation, or single-fiber electromyography. RESULTS: In 2 years of surveillance, 57 confirmed cases were reported. There were 34 generalized and 18 ocular reports of juvenile myasthenia gravis plus 5 congenital myasthenic syndrome cases. There were 14 incident cases in 2010 and 6 in 2011. Age of onset ranged from “birth” to 17 years for the generalized form compared with 18 months to 11 years for the ocular subtype. Positive acetylcholine receptor titers were found in 22 (67%) of 33 generalized cases and 8 (44%) of 18 ocular patients. Of patients started on pyridostigmine, improvement was noted in 33 (100%) of 33 generalized cases and 15 (88%) of 17 ocular cases. CONCLUSIONS: This study represents the largest descriptive series of pediatric myasthenia in North America and provides valuable information about clinical characteristics. A high index of suspicion is important for this treatable disease. Children generally respond promptly to readily available therapies.

Clinical features and evolution of juvenile myasthenia gravis in a French cohort

“…Furthermore, disease progression seems to be favorable in these children, with most being stable or in complete remission by the end of our study (69%). However, we did not find a higher rate of remission, as has been reported …”

“…JMG is rare, with an incidence of 1.0 to 5.0/1,000,000/year in children aged 0–9 years (3%–15% of all MG cases) in Europe . The incidence is similar in North America and Africa, but apparently higher in Asia, where children can account for >50% of all patients with MG and tend to have predominantly ocular MG …”

Clinical and epidemiological features of myasthenia gravis in Chilean population

“…We found no thymoma in the juvenileonset MG and only four patients with thymoma were older than sixty at the age of onset. 27 There was a difference in the sex composition of the prepubescent and post-pubertal groups in our study: no sex predominance in the first group and with overwhelming predominance of female in the post-pubertal group. 14,21,22 The relatively high frequency of thymoma in patients living in the mining counties may indicate an association between thymoma and mining activities, but we found no evidence for this.…”

Early onset bilateral juvenile myasthenia gravis masquerading as simple congenital ptosis

“…In a study by VanderPluym et al on clinical characteristics of pediatric myasthenia, almost 36% of the patients had ocular myasthenia and the age for the same ranged from 18 months to 11 years [10]. 8 out of 18 patients (44%) were under 3 years of age and 10 patients presented with bilateral ptosis [10].…”

“…8 out of 18 patients (44%) were under 3 years of age and 10 patients presented with bilateral ptosis [10]. The clinical features in the juvenile myasthenia group showed a predominance of generalized symptoms (65%) compared to exclusively ocular symptoms (35%).…”