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

Primary Sjogren's Disease Coexisting With Myasthenia Gravis: Two Distinct Autoimmune Diseases Successfully Treated With a Rituximab-Based Induction Regimen

Primary Sjögren's syndrome (pSS) and myasthenia gravis (MG) are autoimmune diseases and are rarely reported in coexistence. MG is a chronic autoimmune neuromuscular disease where antibodies bind to acetylcholine receptors or to functionally related molecules in the postsynaptic membrane, weakening the skeletal muscles and causing diplopia, ptosis, and difficulty in breathing and swallowing. In this report, we discuss the case of a 43-year-old female patient who presented with dry eyes, weight loss, fatigue, ptosis, dysarthria, and quadriparesis, which ultimately led to the diagnosis of pSS and MG. Severe dry eyes, myasthenic symptoms, hypokalemic paralysis, and pancytopenia were among the disease and treatment-related consequences that had to be managed during the course of treatment. The symptoms of MG and pSS were initially managed with high-dose corticosteroids, azathioprine, and pyridostigmine/neostigmine. Escalation to an induction regimen based on rituximab was required due to persistent disease activity of both MG and pSS. Significant hematological and clinical improvements were noted after treatment, highlighting rituximab's effectiveness in inducing remission in these overlapping autoimmune diseases. To the best of our knowledge, this is the first case in the literature where these coexisting diseases were simultaneously, successfully treated with a rituximab-based induction regimen.

Clinical features of myasthenia gravis with neurological and systemic autoimmune diseases

Multiple reports on the co-existence of autoimmune diseases and myasthenia gravis (MG) have raised considerable concern. Therefore, we reviewed autoimmune diseases in MG to explore their clinical presentations and determine whether the presence of autoimmune diseases affects the disease severity and treatment strategies for MG. We reviewed all the major immune-mediated coexisting autoimmune conditions associated with MG. PubMed, Embase and Web of Science were searched for relevant studies from their inception to January 2023. There is a higher frequency of concomitant autoimmune diseases in patients with MG than in the general population with a marked risk in women. Most autoimmune comorbidities are linked to AChR-MG; however, there are few reports of MuSK-MG. Thyroid disorders, systemic lupus erythematosus, and vitiligo are the most common system autoimmune diseases associated with MG. In addition, MG can coexist with neurological autoimmune diseases, such as neuromyelitis optica (NMO), inflammatory myopathy (IM), multiple sclerosis (MS), and autoimmune encephalitis (AE), with NMO being the most common. Autoimmune diseases appear to develop more often in early-onset MG (EOMG). MS coexists more commonly with EOMG, while IM coexists with LOMG. In addition, MG complicated by autoimmune diseases tends to have mild clinical manifestations, and the coexistence of autoimmune diseases does not influence the clinical course of MG. The clinical course of neurological autoimmune diseases is typically severe. Autoimmune diseases occur most often after MG or as a combined abnormality; therefore, timely thymectomy followed by immunotherapy could be effective. In addition, thymoma-associated AChR MG is associated with an increased risk of AE and IM, whereas NMO and MS are associated with thymic hyperplasia. The co-occurrence of MG and autoimmune diseases could be attributed to similar immunological mechanisms with different targets and common genetic factor predisposition. This review provides evidence of the association between MG and several comorbid autoimmune diseases.

Rare Manifestation of Sjögren's Syndrome as Unilateral Facial Paralysis: A Case Report and Literature Review

Herein, we present a unique case of Sjögren's syndrome (SS) first presenting as facial palsy, as well as a literature review of case reports describing SS-associated facial paralysis. A PubMed search for papers containing the keywords Sjögren's syndrome or Sjögren's disease, as well as facial paralysis, facial paresis, facial palsy, or Bell's palsy, was performed. Articles not in English and cases of SS not involving facial paralysis were excluded. Appropriate articles were reviewed for patient demographics and symptoms of SS, including laterality of facial paralysis, cranial nerve involvement, and comorbid diseases. House-Brackmann grades were annotated based on either assignment by individual case reports or the authors' descriptions when sufficient details were present. Of 43 peer-reviewed articles found, 14 were both in the English language and provided adequate information on a total of 16 patients with facial paralysis and SS diagnosis. Ultimately, SS and other systemic autoimmune disorders should be considered in the differential diagnosis of patients presenting with insidious onset facial paralysis.

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

Objectives. To investigate the presence of serum antinuclear antibody (ANA) and anti-double-stranded DNA antibody (anti-dsDNA) in patients with myasthenia gravis (MG) and analyze the clinical characteristics and prognostic factors associated with MG. Methods. We retrospectively enrolled 363 patients with MG and analyzed the clinical characteristics and follow-up data between patients positive and negative for ANA and anti-dsDNA. We defined a Myasthenia Gravis Activities of Daily Living (MG-ADL) reduction as a main prognosis predictor and used logistic regression to determine independent factors associated with prognosis. We built a nomogram to predict prognosis and evaluate the internal validity of the model. Results. Ninety-eight (27.0%) patients were positive for ANA, and 51 (14.0%) were positive for anti-dsDNA. Patients positive for ANA and anti-dsDNA antibodies tended to be female and positive for acetylcholine receptor antibody (AChR-Ab). The rate of thymoma was higher in anti-dsDNA-positive patients with MG (p-dsDNA-MG) than in patients negative for anti-dsDNA (49.0% vs. 26.0%, $p=0.001$ ), and p-dsDNA-MG was associated with reduced MG-ADL score. Regression analysis showed that except for age of onset ( $\text{OR}=0.986$ , $95\%\text{CI}=0.973–0.999$ , $p=0.037$ ), anti-dsDNA ( $\text{OR}=2.800$ , $95\%\text{CI}=1.381–5.679$ , $p=0.004$ ), ptosis ( $\text{OR}=2.930$ , $95\%\text{CI}=1.827–4.699$ , $p<0.001$ ), and eye movement disorder ( $\text{OR}=2.815$ , $95\%\text{CI}=1.672–4.741$ , $p<0.001$ ) were independent predictive factors of a favorable prognosis of MG. These predictors were used to generate a nomogram with an excellent predictive value. Conclusions. Being female and the presence of AChR-Ab were features of ANA- or anti-dsDNA-positive MG. The presence of anti-dsDNA was associated with a favorable prognosis of MG.

Association of early-onset myasthenia gravis and primary Sjögren's syndrome: a case-based narrative review

Coexistent myasthenia gravis (MG) and primary Sjögren's syndrome (pSS) is an absolute rarity. That is kind of a surprise as both entities seem to share the same corresponding immunologic mechanisms. We hereby report the case of a 41-year-old woman with coincident early-onset MG (EOMG) and pSS. Because EOMG was the leading clinical feature, she was primarily treated by innovative non-intubated uniportal subxiphoid video-assisted thoracoscopic surgery (VATS) thymectomy. As the association of EOMG and pSS is so unusual, we contextualize our findings with the relevant literature. Particular relevance is an anti-nuclear antibody screening throughout the clinical course of MG and-in reverse-a screening for MG variables when pSS patients complain either muscle fatigability or fatigable ptosis. As pSS patients do not develop any serious morbidity, supervising MG progress in patients with both diseases is of utmost importance. Apart from conscientious pSS diagnosis, prompt adjusting of EOMG progress is the essential aspect of targeted treatment. In this context, it is relevant that therapeutic decisions are made in a multidisciplinary approach. Due to its rarity, multicenter prospective studies of larger sample sizes are indispensably needed to obtain a better understanding of this unusual link.