Objective: To identify patients with co-occurring myasthenia gravis (MG) and primary Sjögren’s syndrome (pSS) at Virginia Commonwealth University (VCU).

Background: To date there are 17 reported cases of coexisting MG and pSS in the literature. 70.6% of these patients were AChR antibody positive. Most patients were treated successfully with cholinesterase inhibitors and corticosteroids. 2 patients required intravenous immune globulins (IVIg) or plasmapheresis (PLEX) for respiratory impairment.

Methods: We performed a retrospective chart review of patients seen at VCU in the past 5 years with coexisting MG (ICD10: G70.0) and pSS (ICD10: M35.0) Each chart was carefully reviewed by the authors to ensure there was ample documentation to clinically characterize these patients and absence of diagnostic uncertainty.

Results: 7 patients were identified to have both MG and pSS. Upon further review 3/7 were not only diagnosed correctly but complete medical records were available to review. The presentation of these 3 patients differed greatly than the 17 previously reported patients. 2/3 were seronegative with diagnosis electrodiagnostically confirmed, and 1/3 was seropositive (without AChR binding antibodies but positive modulating antibodies). All 3 had positive SSB antibodies and 2 had both SSA/SSB antibodies. The MG symptoms were severe with all patients having oculobulbar and generalized weakness and respiratory impairment in 2. Due to the severity of the disease all 3 subjects were maintained on IVIg. 2 used pyridostigmine and one was maintained also on mycophenolate mofetil. 1/3 was maintained on hydroxychloroquine for pSS.

Conclusion: In contrast to previous reports, we present 3 cases of coexisting MG and pSS, all of whom have severe disease and none of which harbor AChR binding antibodies. These 3 cases serve to expand the clinical spectrum of these rare overlap syndromes.