Immunological, Physical, and Psychological Interventions in Young-Onset Stiff-Person Syndrome.

Dear Editor, Young-onset stiff-person syndrome (SPS) is rare, with most patients presenting initially to non-neurology doctors, and the majority not being diagnosed until adulthood.1 A 16-year-old female presented with progressively unsteady gait that first appeared at the age of 13 years. At 12 years old she noticed generalized body aches when remaining in one position for too long, and at 14 years old she started experiencing recurrent falls, leading to worsening basophobia. At home, she was extremely anxious about climbing stairs or taking a shower, and she feared crossing roads when outside. She was easily startled by sound and touch sensations, which triggered painful muscle spasms. She had a normal intellect and no relevant family history. She first sought medical help at 15 years old, and was diagnosed with anxiety and depression. After receiving a third opinion, the patient consulted a neurologist. A physical examination revealed prominent axial stiffness and rigidity (Supplementary Video 1, Section 1 in the online-only Data Supplement). She had a forward-leaning posture with thoracic and cervical hyperlordosis. Her gait was stiff, wide-based, and high-stepping due to stiffness. She had an exaggerated startle response and a positive head-retraction reflex. Laboratory investigations revealed elevated creatinine kinase (302 U/L; normal, 29–168 U/L) and lactate dehydrogenase (275 U/L; normal, 130–250 U/L). Antinuclear antibodies were positive, and extractable nuclear antigens were negative. Serum anti-glutamic-acid decarboxylase (anti-GAD) antibodies were strongly positive, at >2,000 IU/mL (normal, <10 IU/mL). CSF demonstrated five unique intrathecal oligoclonal bands. Brain MRI was unremarkable, while whole-spine MRI demonstrated premature scoliosis. Serology tests for type 1 diabetes and autoimmune thyroid disease were negative. Surface EMG revealed continuous motorunit activity of the paraspinal muscles, which increased during spontaneous painful muscle spasms (Supplementary Video 1, Section 2 in the online-only Data Supplement). Treatment with clonazepam (0.5 mg TDS) and baclofen (10 mg BDS) was inadequate, and so two cycles of IVIG at 0.5 mg/kg were administered over 5 days. Repeat EMG demonstrated a significant reduction in motor-unit activity, and her gait visibly improved (Supplementary Video 1, Section 3 in the online-only Data Supplement). Weekly physical therapy sessions comprising massage and stretching exercises significantly relieved the muscle stiffness, while psychotherapy and cognitive behavioral therapy (CBT) alleviated her anxiety and basophobia. The clinical improvement was sustained at 3 months post-IVIG, and the patient resumed participating in sports at school. Her anti-GAD antibody had decreased to 250 IU/mL. Symptom progression was reviewed at 3-monthly follow-ups. Young-onset SPS accounts for 5% of SPS cases. The median age at symptom onset is 11 years (range, 1–15 years).1 The most commonly associated antibody is anti-GAD65, followed by antiglycine-receptor antibody. Paraneoplastic antiamphiphysin antibody has been reported with a pediatric malignancy.3 Concurrent autoimmune diseases are common and must be screened for, especially autoimmune thyroid disease and autoimmune diabetes. A family history of autoChun Seng Phua Shalini Bhaskar