Autoimmune neuromuscular disorders in childhood

Don't Miss This! Red Flags in the Pediatric Eye Examination: Ophthalmoplegia in Childhood

Paralytic strabismus in children is rare, occurring in about 0.1% of children. This rate is far less common than the 3% rate usually noted for comitant strabismus. The relative rates of ocular motor pareses were fourth nerve palsies in 36%, sixth in 33%, third in 22%, with multiple ocular motor nerve palsies in 9%. In a single population series from Minnesota, few cases were associated with neoplasm. However, institutional case series reports a high rate of neoplasm for acquired third nerve and sixth nerve palsies after excluding trauma and congenital causes. Tumor is rare in children with fourth cranial nerve palsies, usually associated with other neurologic disease. Rare causes of external ophthalmoplegia, to be considered when the motility pattern is variable or not fitting an ocular motor nerve pattern, include myasthenia gravis and congenital fibrosis of the extraocular muscles. Myasthenia most often presents as ptosis with exotropia. Rarer still is involvement of the extraocular muscles in childhood thyroid disease.

Therapeutic Plasma Exchange Use in Pediatric Neurologic Disorders at a Tertiary Care Center: A 10-Year Review

Pediatric neurologic conditions requiring therapeutic plasma exchange are rare in children and literature is sparse. The study aims to determine the outcomes, safety, and feasibility of therapeutic plasma exchange treatment in pediatric neurologic disorders. This retrospective analysis looked at the outcomes and safety of therapeutic plasma exchange in children (n = 50) with neurologic conditions. Patient age ranged <1 to 19 years old with a mean of 10.35 years. Of the 50 children treated with plasmapheresis, 26 patients received inpatient rehabilitation. At discharge, functional status can be summarized as follows: 24 (48%) with mental status impairment, 10 (20%) with vision impairment, 19 (38%) with bladder incontinence, and 37 (74%) with motor impairment. Three-month follow-up: 30% with mental status impairment, 10% with vision impairment, 18% with bladder incontinence, and 52% with motor impairment. Therapeutic plasma exchange is an effective and safe therapy for neurological conditions in the pediatric population.

Tacrolimus Improves Symptoms of Children With Myasthenia Gravis Refractory to Prednisone

BACKGROUND

Myasthenia gravis tends to affect children in China. Oral pyridostigmine and prednisone could effectively improve the symptoms, but multiple side effects become a major concern after long-term oral prednisone. To avoid the long-term complications of prednisone therapy and to obtain more satisfactory improvement, we tested the efficacy and safety of tacrolimus in children with myasthenia gravis.

METHODS

Children with myasthenia gravis who had not achieved satisfactory improvement or who experienced severe side effects after prednisone therapy were recruited between January 2015 and December 2016 at Tongji Hospital. All the children were treated with tacrolimus 1 mg to 2 mg daily and the dose was adjusted on the basis of the clinical response and the serum concentration. The dosage of prednisone, the severity of symptoms, blood samples, the serum concentration of tacrolimus, and titers of antiacetylcholine receptor antibodies were evaluated every four weeks.

RESULTS

Fourteen children were enrolled. One child withdrew two weeks after the enrollment. Thirteen children have completed the therapy for one year. At the end point, the dosage of prednisone was significantly decreased (P < 0.05), the symptoms were evaluated by the quantitative myasthenia gravis score, and myasthenia gravis-specific manual muscle testing and myasthenia gravis-activities of daily living scores were significantly improved (P < 0.05, P < 0.05, and P < 0.01, respectively). More importantly, ten (76.9%) patients had completely discontinued prednisone, and the major side effects were nearly reversed. The mean titer of antiacetylcholine receptor antibodies significantly dropped from 1.96±2.62 nmol/L to 0.70±1.04 nmol/L (P < 0.05). No severe adverse events were reported.

CONCLUSIONS

Our results suggest that tacrolimus is a promising agent for children with refractory myasthenia gravis. Randomized clinical trials are needed to confirm the observation.

Update on juvenile myasthenia gravis

PURPOSE OF REVIEW

Juvenile myasthenia gravis is a relatively rare autoimmune neuromuscular disorder. The pathophysiology of juvenile myasthenia gravis is similar to that of adult myasthenia gravis, though there remain important differences regarding presentation and therapeutic options. We review the pathophysiology, clinical presentation, and treatment options for juvenile myasthenia gravis.

RECENT FINDINGS

Randomized clinical studies of myasthenia gravis have been carried out primarily in adult populations. As juvenile myasthenia gravis is rare, it has been difficult to collect prospective randomized controlled data to evaluate treatment outcomes and efficacy. A recent retrospective series suggests that, as in adult myasthenia gravis, thymectomy is a viable therapeutic option for selected cases of generalized juvenile myasthenia gravis. This is corroborated by the clinical experience of the authors in a referral center with a cohort of patients affected by juvenile myasthenia gravis over a number of years.

SUMMARY

Recent studies illustrate that some, but not all, adult research on myasthenia gravis is applicable to children and adolescents with juvenile myasthenia gravis. Adult research can inform pediatric studies, but should not be regarded as a substitute for dedicated research in those populations.

Enuresis and more

We describe Pervasive Refusal Syndrome, an important but rare, debilitating condition that may present to paediatric services. Although previous reports have described improvement seen with care delivered in the mental health setting, we have demonstrated treatment predominately delivered in a paediatric ward environment associated with successful recovery.

Clinical characteristics of pediatric myasthenia: a surveillance study

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.