Stiff person syndrome masquerading as multiple sclerosis

Background Stiff person syndrome (SPS) is a rare neuroimmunological disorder presenting with a wide variety of signs and symptoms that mimic neuro-inflammatory diseases, such as multiple sclerosis (MS), thus delaying diagnosis. Methods We performed a retrospective chart review of over 100 patients with SPS who were treated at Johns Hopkins Hospital and identified five patients previously diagnosed with MS. Results Patients were female with a mean age of 53 years old (range 43–64). Mean time to SPS diagnosis was 5.5 years. They presented with typical SPS features (axial/leg spasms, torso rigidity, hyperlordosis, and gait instability) as well as atypical features (hemiparesis, hemisensory dysfunction, fine motor impairment) and were all initially given a diagnosis of MS. In all patients, brain MRI demonstrated non-specific white matter lesions and CSF was negative for intrathecal antibodies in the 4 out of 5 patients who underwent lumbar puncture. SPS diagnosis was supported by elevated anti-glutamic acid decarboxylase (GAD65) antibodies in each patient. Two patients were treated with disease-modifying therapies for MS before being diagnosed with SPS. Following diagnosis with SPS, the patients were treated with varying combinations of immunosuppressants and symptomatic therapies resulting in stabilization or improvement in four of the patients. Conclusion We present five patients with SPS, who were initially thought to have MS, including one patient treated with three different MS therapies due to “disease progression”. These cases demonstrate the need to consider less common neuroimmunological disorders, such as SPS, especially in patients with atypical features for MS.