Sjögren's Disease and Stiff Person Syndrome: A case series highlighting a rare but significant autoimmune overlap

A co-occurrence between Sjogren's Disease (SjD) and Stiff Person Syndrome (SPS) is extremely rare, with only two prior case reports in the literature. This case series investigates this potential association.

We present three cases with confirmed diagnosis of SPS and SjD. All the patients were evaluated and managed for both conditions in our institution.

Three patients (2 females, 1 male; ages 59-71) were diagnosed with SPS and SjD. They met 2016 ACR/EULAR classification criteria for SjD. All the patients had positive serum anti-GAD65 antibodies, with one case showing anti-GAD65 antibodies in the CSF. In addition, at least one other autoimmune disorder was present in each case. The clinical manifestations of SPS preceded the onset of sicca symptoms by several years in all three cases. Patients demonstrated varying responses to therapy and the outcome was overall unfavorable. One patient underwent hematopoietic stem cell transplant for management of SPS, and two patients suffered major intracranial hemorrhages, one of which was fatal.

This series suggests a possible association between SPS and SjD. Clinicians should maintain a high index of suspicion for this overlap to facilitate early diagnosis and management. Larger studies are needed to confirm this association.