Clinical features of chronic inflammatory demyelinating polyneuropathy: a single-center experience with 33 patients

Background: Chronic inflammatory demyelinating polyneuropathy (CIDP) is an immune-mediated neuropathy with heterogeneous clinical presentations. Although several clinical subtypes, including typical and variants, have been described, evidence regarding their distribution and treatment outcomes remains limited, particularly for CIDP variants. Methods: We retrospectively analyzed 33 consecutive patients diagnosed with CIDP at Kumamoto University Hospital between January 2020 and March 2025. Clinical data included demographic characteristics, disease duration, subtype classification, electrophysiological and cerebrospinal fluid (CSF) findings, imaging findings, treatment details, and treatment responsiveness. Subtypes were classified according to the 2021 EAN/PNS diagnostic criteria. Treatment responsiveness was defined as objective improvement confirmed by at least two neurologists. Results: Among the 33 patients, 36.4% had typical CIDP and 63.6% had CIDP variants, including distal (39.4%), multifocal (15.2%), motor (3.0%), and sensory (6.0%) subtypes. Distal CIDP was the most frequent subtype. Patients with multifocal CIDP experienced the longest diagnostic delays (mean, 4.6 years) due to fewer demyelinating findings on electrophysiological studies. The MRC sum score was lowest in typical CIDP, suggesting greater disease severity. Intravenous immunoglobulin (IVIg) demonstrated high efficacy across all subtypes, including multifocal CIDP, in contrast to previous reports of lower responsiveness. During a mean follow-up period of 5.1 years, 78.8% of patients required maintenance therapy, most commonly IVIg and corticosteroids. No changes in clinical subtypes were observed during follow-up. Conclusion: In this single-center study, variants outnumbered typical CIDP, reflecting the case mix at a specialized tertiary referral center. Multifocal CIDP showed the longest diagnostic delays. IVIg demonstrated high efficacy across subtypes, including multifocal CIDP, contrasting with previous reports. These findings highlight the importance of improving diagnostic accuracy and establishing individualized long-term treatment strategies for CIDP.