Clinical analysis of skeletal muscle and small fiber involvement associated with anti-contactin-associated protein-like 2 antibodies positive Morvan syndrome / 中华神经科杂志

ABSTRACT

Objective:To analyze the clinical data of a patient with anti-contactin- associated protein-like 2 (CASPR2) antibodies-related Morvan syndrome (MoS) and the related literature, and summarize the clinical characteristics of MoS patients.Methods:Clinical data of a CASPR2 antibodies-related MoS patient who was admitted in the Department of Neurology, the First Medical Center of Chinese People′s Liberation Army General Hospital in June 2021 were collected. CASPR2 IgG was detected by cell-based assay. Positron emission tomography/computed tomography (PET/CT), skin sympathetic response (SSR) and other examinations were performed. Clinical profiles of MoS patients were summarized by database retrieval.Results:The patient was a 55-year-old man presenting with peripheral nerve hyperexcitability, autonomic dysfunctions, neuropsychiatric symptoms and pain. Physical examination showed cognitive impairment, muscle quivering and absent deep-tendon reflexes. There was no family history of MoS and poisons exposure in this patient. Auxiliary examination showed serum creatine kinase was elevated (570 U/L) and antinuclear antibodies were positive (granular-type 1∶320). Other rheumatic and immunological antibodies, erythrocyte sedimentation rate, autoantibody profile, tumor marker, thyroid function, etc, were normal. Cerebrospinal fluid (CSF) protein and immunoglobulin were slightly higher. CASPR2 antibodies were positive in both serum and CSF (serum: 1∶100, CSF: 1∶10). Needle electromyography showed myokymic discharges, motor and sensory nerve conduction velocities were normal. SSR showed no waveform was elicited from both hands and feet. Cranial magnetic resonance imaging suggested scattered ischemic changes in the brain. PET/CT showed local metabolism increased slightly in soft tissues of bilateral shoulder and back, right lumbar and back muscles and bilateral gluteus medius. A total number of 232 cases of MoS patients were found in literature reports, most of which were male. The most common clinical manifestations were sleep disorders, and cognitive deficits accounted for 32.3%. Among them, skeletal muscle involvement was found in only 1 case by PET, and 4 patients had SSR abnormalities. Most of the patients had favorable neurological outcomes after the immunotherapy.Conclusions:MoS, as an autoimmune syndrome, may present with high uptake of skeletal muscle in PET/CT examination. Skeletal muscle involvement is a rare clinical manifestation of this disease. SSR as an electrophysiological test to evaluate autonomic neuropathy, its clinical value should be further strengthened.