Abstract
BACKGROUND Morvan syndrome is an autoimmune disease associated with autoantibodies against proteins of the voltage-gated potassium channel complex, particularly Caspr2. Telitacicept, a recombinant TACI-Fc fusion protein that dually inhibits BAFF and APRIL cytokines, has shown efficacy in refractory autoimmune diseases. This report describes a 54-year-old man with Morvan syndrome presenting with peripheral nerve hyperexcitability and sleep disturbance who responded to telitacicept after conventional immunotherapy failed. CASE REPORT In September 2023, a 54-year-old male patient presented with weakness, muscle cramps, burning sensation, pain in both lower limbs, and walking instability. He also reported severe sleep disturbance, cognitive impairment, difficulty concentrating, restlessness, and depression. Physical examination revealed muscle fasciculation, myokymia, hyperhidrosis, frequent micturition, and significant weight loss. Laboratory test results confirmed positive anti-Caspr2 antibodies in the serum. Due to pre-existing blood glucose concerns, the patient declined high-dose corticosteroid pulse therapy. After thorough discussion of alternative options, including intravenous immunoglobulin, plasma exchange, and rituximab, the patient opted for subcutaneous telitacicept at a dose of 160 mg weekly. Within the second week of treatment, notable improvements were observed in muscle myokymia, neuropathic pain, and sleep disturbances. Over the following 6 months, the patient achieved complete clinical remission with no recurrence of symptoms and was able to discontinue corticosteroids. No infections or other adverse effects were reported during the treatment period. CONCLUSIONS This report has highlighted the approach to diagnosing Morvan syndrome, which can present with peripheral nerve hyperexcitability, and supports the role of immunomodulatory therapy, including telitacicept.