SHM Converge Scientific Abstract ePoster Gallery-Stiff Person Syndrome Presenting as Non-Epileptic Seizure Disorder

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This case report describes a 44-year-old woman with a 5-year history of episodic shaking initially thought to represent seizures or psychosomatic events. Despite multiple prior video EEG studies showing no epileptiform activity, her symptoms worsened and became more frequent, especially with stress. During hospitalization, she developed episodic truncal and proximal muscle rigidity with preserved awareness, anisocoria, autonomic instability, elevated creatine kinase, and markedly elevated serum anti-GAD antibodies, all supporting a diagnosis of stiff person syndrome (SPS). MRI showed periventricular white matter hyperintensities, while CSF and paraneoplastic testing were unrevealing.<br /><br />Her course was complicated by critical illness, including obtundation, hypotension, tachycardia, tachypnea, stress cardiomyopathy, acute deep vein thrombosis, and a retroperitoneal hematoma that limited anticoagulation. She was treated with plasmapheresis and stress-dose steroids, with full recovery of neurological and cardiovascular function, and was discharged to rehabilitation. Plasmapheresis was chosen over IVIG because of her prothrombotic state.<br /><br />The report emphasizes that SPS is a rare autoimmune neurologic disorder associated with anti-GAD antibodies and impaired GABAergic inhibition, leading to muscle stiffness and co-contraction. It also highlights that SPS can present atypically and be mistaken for seizure disorder or non-epileptic events, contributing to significant diagnostic delay and patient distress. The authors stress the importance of considering SPS in patients with unexplained episodic rigidity or shaking, even when presentations are unusual, and note that greater awareness and research are needed to improve diagnosis and treatment.

Asset Subtitle

Catherine Ye

Meta Tag

Author List Bilal Khan, Catherine Ye, Maarij Baig, Nishma Jain

Category Clinical Vignettes

Concept Stiff Person Spectrum Disorder

Concept GAD65 Antibody

Concept Rigidity

Concept Benzodiazepines

Concept GABAergic Inhibition

Distinguished Non-Finalist

Presenter Organization Rutgers New Jersey Medical School

Presenting Author Catherine Ye

Track Adult

Keywords

stiff person syndrome

anti-GAD antibodies

episodic shaking

muscle rigidity

autoimmune neurologic disorder

video EEG

plasmapheresis

stress cardiomyopathy

diagnostic delay

GABAergic inhibition

Stiff Person Spectrum Disorder

GAD65 Antibody

Rigidity

Benzodiazepines

GABAergic Inhibition