Myasthenia Gravis Coexisting With Primary Sjögren's Syndrome: Report of Three Cases and Literature Review

Abstract

Objective: The coexistence of myasthenia gravis (MG) and primary Sjögren's syndrome (pSS) is rarely reported. This study aims to describe the clinical features, treatment and outcome of MG coexisting with pSS. Materials and Methods: Herein we reported three cases with the two coexisting diseases, and also searched the PubMed, Medline databases, and China Wanfang databases for the relevant case reports written in English, Chinese, or Japanese with detailed data. Results: We reviewed a total of 17 patients with both diseases. Fifteen patients were female. The median age at onset was 48 years (range 28–78 years). MG was the initial disease in nine of 17 cases. The median interval between the onsets of the two diseases was 30 months (range 7 months to 20 years). The symptoms of MG included fatigable ptosis (64.7%), bulbar symptoms (58.8%), muscle fatigability (64.7%), diplopia (64.7%), dyspnea (23.5%), and facial paralysis (5.9%). Anti-acetylcholine receptor antibody was positive in 70.6% patients. All the patients had sicca symptoms. Manifestations of pSS also included swollen exocrine glands (23.5%), joint pain (23.5%), hair loss (11.8%), leukopenia (11.8%), recurrent oral ulcers (5.9%), Raynaud phenomenon (5.9%), and fever (5.9%). ANA positivity was present in 70.6% patients, anti-SSA positivity in 47.1%, and double positivity of anti-SSA and anti-SSB in 17.6%. There were 12 patients (70.6%) with two autoimmune diseases (pSS and MG), and five patients with more than two autoimmune diseases. Cholinesterase inhibitors were the most commonly prescribed drugs (82.4%). Seven patients received thymectomy and one patient improved after the operation. Two patients were given intravenous methylprednisolone pulse therapy, and four patients oral steroids combined with immunosuppressants initially. Intravenous immunoglobulin and plasma exchange were used in two patients, respectively, for the respiratory failure. All the patients improved following treatment except one patient who died of MG crisis due to medication withdrawal. Conclusion: The coexistence of SS with MG is quite rare. The onset of MG may occur before or after the diagnosis of SS. Co-morbidity with MG does not seem to adversely affect the course of SS. Thus, controlling the progress of MG is the critical aspect of treatment.

Anti-dsDNA Is Associated with Favorable Prognosis in Myasthenia Gravis: A Retrospective Study

“…The relationship between MG and other ADs is also still controversial to date. Similar to the findings observed in patients with SLE, MG combined with AITD or RA tended to be a milder form of the disease, [3,26] and comorbidity with MG did not seem to adversely affect the course of SS [32]. However, some studies showed that patients with both MG and HT had a more severe MG status and that MG in association with other autoimmune disorders had a less favorable prognosis [35,62].…”

“…Furthermore, patients with MG and SLE were previously shown to predominantly have generalized MG [31]. Most MG patients coexisting with primary Sjögren syndrome were classified as generalized MG, [32] while thyroid diseases showed the highest association rate with ocular early-onset MG [33]. 6 Acta Neurologica Scandinavica Thymoma, a rare tumor of the thymus, was found to be associated with many ADs including MG, pure red cell aplasia, and SLE [34].…”

Myasthenia Gravis with Idiopathic Inflammatory Myopathy and Sjögren Syndrome, A Triad of Immune-Mediated Diseases

“…Conversely, the association between SS and MG, mainly in the early stage, has been reported. MG was reported before the diagnosis of SS, with initial bulbar symptoms of MG and predominantly positive anti-Ro/SSA antibodies, as in the case presented, and the presence of constitutional symptoms should be considered significant, as it may be associated with thymoma and mediastinal tumor masses [8][9][10]. In this case, there was no thymoma or mediastinal mass.…”

Clinical features of myasthenia gravis with neurological and systemic autoimmune diseases

“…SS is a B-cell mediated autoimmune disease with anti-SSA (Ro), anti-SSB, and ANA Abs. The frequency of neurological involvement, such as peripheral neuropathy, aseptic meningitis, NMO, and MS in SS is up to 20% ( 98 – 100 ). However, the coexistence of MG and SS has rarely been reported.…”

“…Li et al. reviewed 17 patients with both diseases and revealed that MG may develop before or after SS ( 100 ). The coexistence of both diseases predominantly affected female and EOMG patients.…”