Video-assisted thoracoscopic thymectomy in juvenile myasthenia gravis

Effectiveness of thymectomy in juvenile myasthenia gravis and clinical characteristics associated with better outcomes

Thymectomy is an established treatment in adult myasthenia gravis, but its exact role in juvenile myasthenia gravis (JMG) is still uncertain. Thymectomy is frequently considered in the treatment of severe, medically refractory JMG. Surgical approaches have evolved from open median sternotomy to the more cosmesis-preserving thoracoscopic approach. This paper reviews current evidence on the effectiveness of thymectomy in JMG and discusses clinical characteristics which may be associated with improved outcomes. 17 studies including 588 patients who underwent thymectomy from 1997 to 2020 were found, which either reported uncontrolled cohorts undergoing thymectomy, or compared cohorts undergoing different surgical approaches. An improvement in clinical status or reduced requirement for medical therapy following thymectomy was seen in 453 patients (77%). Complete remission was seen in 40% (n = 172/430). Thoracoscopic approaches may provide improved outcomes, fewer complications, and better cosmetic outcomes. Better surgical outcomes may be associated with early intervention, intervention after the onset of puberty, being acetylcholine receptor antibody positive, having more severe disease and the presence of hyperplastic thymic tissue. However, analysis remains hindered by the limitations of the currently available retrospective studies of small cohorts. Nonetheless, available literature suggests a role for thymectomy in JMG patients, especially those with certain clinical characteristics.

The role of thymectomy in the treatment of juvenile myasthenia gravis: a systematic review

BACKGROUND

The role of thymectomy in the treatment of juvenile myasthenia gravis (JMG) is poorly defined. The objective of this systematic review was to evaluate the effect of thymectomy on survival, disease severity, and peri-operative complications for patients with JMG.

METHODS

A search of MEDLINE, EMBASE, and the Cochrane Library (1/1/2000-3/1/2016) identified all English language, human studies of thymectomy for JMG. The population was patients with JMG age ≤18 years who underwent thymectomy (comparator group was unexposed to thymectomy). Outcomes included survival, disease severity, and post-operative complications. Data extraction was performed by independent reviewers.

RESULTS

Sixteen retrospective studies included 1131 participants with JMG and 488 (43%) underwent thymectomy. Post-operative improvement in JMG severity occurred for 77% (n = 376/488). Comparisons of thymectomy to non-operative management were mixed. Post-operative complications were poorly recorded. Power to compare surgical approaches was limited. Outcomes specific to antibodies, surgical pathology findings, severity of JMG, and timing of thymectomy were sparse.

CONCLUSIONS

Existing data regarding thymectomy for JMG are limited and entirely retrospective. The majority of patients who underwent thymectomy had improvement in disease severity and post-operative complications were rare. Prospective, multicenter study of thymectomy for JMG is warranted.

Management of juvenile myasthenia gravis

Juvenile myasthenia gravis is an uncommon autoimmune disorder. Its management is not standardized. Juvenile myasthenia gravis is pathophysiologically similar to myasthenia gravis in adults. However, a number of significant particularities related to race, age at onset, severity, and antibody status complicate the management. We summarize the unique clinical features of juvenile myasthenia gravis and review the therapeutic options.

Visual and systemic outcomes in pediatric ocular myasthenia gravis

PURPOSE

To evaluate visual and systemic outcomes in pediatric patients with purely ocular myasthenia gravis (OMG) treated at the Children's Hospital of Philadelphia.

DESIGN

Retrospective chart review.

METHODS

Pediatric patients with OMG seen at a single institution over a 16-year period with a minimum follow-up of 1 year were reviewed. Associations of demographic and clinical characteristics with disease resolution, amblyopia, and development of generalized symptoms of myasthenia gravis were analyzed.

RESULTS

Thirty-nine patients were identified, with a mean age of 5.4 ± 4.8 years and mean follow-up of 4.8 ± 4.3 years. Fifteen patients were treated with pyridostigmine only, 19 (49%) also received steroids, and 15 (38%) underwent thymectomy. Four patients (10%) received steroid-sparing immunosuppressive therapy. Resolution occurred in 10 patients, and generalized symptoms eventually occurred in 9 patients. Although 10 patients were treated for amblyopia, only 1 had amblyopia at the final visit. There was no correlation between sex or age with amblyopia or development of generalized symptoms. Thymectomy, when performed before the onset of generalized symptoms, showed a trend toward protection from the development of generalized symptoms (P = .07).

CONCLUSIONS

In our series, 24% of patients had disease resolution and 23% had generalized symptoms. Our larger cohort confirms previous findings that treated and untreated pediatric patients with OMG have a relatively low risk of developing generalized symptoms and that related amblyopia is readily reversible. Although our treatments were more aggressive than those previously reported, our rates of amblyopia and development of generalized symptoms are comparable.