CIDP Variants Outnumber Typical Cases in Single-Center Cohort

A retrospective, single-center study found that variants of chronic inflammatory demyelinating polyneuropathy (CIDP) accounted for most cases in a tertiary referral cohort, with distal CIDP emerging as the most common subtype and multifocal disease associated with the longest diagnostic delays. Investigators also reported strong treatment responsiveness to intravenous immunoglobulin (IVIg) across subtypes, including multifocal CIDP, contrasting with earlier reports suggesting lower efficacy in that population.¹

Study Overview

Senior author Mitsuharu Ueda MD, PhD, professor at Kumamoto University in Japan, and colleagues evaluated 33 consecutive patients diagnosed with CIDP at Kumamoto University Hospital between January 2020 and March 2025. Investigators examined clinical characteristics, electrophysiological findings, cerebrospinal fluid (CSF) profiles, imaging results, treatment patterns, and therapeutic responses. CIDP subtypes were classified according to the 2021 diagnostic criteria from the European Academy of Neurology and the Peripheral Nerve Society.¹

Among the cohort, typical CIDP accounted for 36.4% of cases (n = 12), whereas variants comprised 63.6%. The distribution of variants included distal CIDP (39.4%), multifocal CIDP (15.2%), motor CIDP (3.0%), and sensory CIDP (6.0%). Notably, distal CIDP was the most common presentation in the study population.¹

The investigators noted that these findings differ from previous reports in which typical CIDP accounts for approximately 50% to 60% of cases. The authors suggested that referral patterns at specialized centers and increased recognition of CIDP variants may have contributed to the higher proportion observed in this cohort.¹

Diagnostic Patterns and Clinical Characteristics

Diagnostic delays varied substantially across subtypes. Patients with typical CIDP had the shortest time from symptom onset to diagnosis, with a mean interval of approximately 1.0 year. In contrast, multifocal CIDP demonstrated the longest diagnostic delay, averaging 4.6 years.¹

The authors attributed these delays to the relative absence of classic demyelinating findings on electrophysiological studies in multifocal CIDP. In several cases, patients were initially misdiagnosed with alternative conditions, including drug-induced neuropathy, idiopathic neuropathy, cervical spondylosis, or tarsal tunnel syndrome.¹

Clinical severity also differed between subtypes. Patients with typical CIDP demonstrated the lowest mean Medical Research Council (MRC) sum scores, suggesting more severe motor impairment compared with variant forms of the disease. Electrophysiological studies similarly indicated greater nerve conduction abnormalities in typical CIDP, including slower motor nerve conduction velocities and prolonged distal and F-wave latencies.¹ In contrast, electrophysiological parameters in multifocal CIDP often showed fewer characteristic demyelinating changes, potentially contributing to diagnostic uncertainty.¹

Treatment Response

IVIg was the most frequently used induction therapy, administered to 32 of the 33 patients (97.0%). Overall response rates were high, with 31 of 32 treated patients demonstrating clinical improvement.¹

Investigators also reported strong responses across subtypes, including a 100% response rate among patients with multifocal CIDP. Corticosteroids were used in approximately one-third of patients and demonstrated a similarly high response rate of 90.9%. Plasma exchange was used in a smaller subset of patients, primarily those with treatment-resistant typical CIDP.¹

Read more: Grip Strength in CIDP: A Practical, Scalable Biomarker for Efficacy and Care Optimization

Overall, these findings contrasted with previous studies suggesting that IVIg may be less effective in multifocal CIDP, potentially reflecting differences in underlying immunopathology between CIDP subtypes.¹

Long-Term Outcomes and Interpretation

During a mean follow-up period of 5.1 years, the majority of patients (78.8%) required ongoing maintenance therapy. IVIg and corticosteroids were the most common long-term treatment approaches, while smaller numbers of patients received subcutaneous immunoglobulin or the neonatal Fc receptor inhibitor efgartigimod. Notably, no patients experienced changes in clinical subtype during follow-up.

The investigators concluded that CIDP variants may be more common than previously reported in specialized referral centers and that multifocal CIDP remains particularly challenging to diagnose due to atypical electrophysiological features.¹ At the same time, the strong treatment responses observed across subtypes highlight the importance of early recognition and prompt initiation of immunotherapy in patients with suspected CIDP.¹

The investigators noted that “these findings highlight the importance of improving diagnostic accuracy and establishing individualized long-term treatment strategies.”

REFERENCES
1. Nomura T, Misumi Y, Ueda M. Clinical features of chronic inflammatory demyelinating polyneuropathy: a single-center experience with 33 patients. Front. Neurol. 2026; 17 (1): 743650. doi: 10.3389/fneur.2026.1743650