Incomplete Presentations in Typical Chronic Inflammatory Demyelinating Polyneuropathy: A Single‐Center, Retrospective Study

Introduction/Aims:
Incomplete forms of typical chronic inflammatory demyelinating polyneuropathy (CIDP) have recently been described, but their frequency and clinical characteristics are uncertain. This study aimed to describe a cohort of patients with incomplete typical CIDP.

Methods:
We retrospectively analyzed 64 consecutive treatment-naïve patients with CIDP. Phenotypes were classified based on detailed motor examinations, and clinical, electrophysiological, and therapeutic characteristics were compared.

Results:
Nineteen (30%) subjects with typical CIDP presented with an incomplete phenotype; 12 (63.2%) exhibited a proximal arm-sparing pattern, 3 (15.8%) a distal arm-sparing pattern, 3 (15.8%) a pure paraparetic form, and 1 (5.2%) had a pure proximal form. In cases without full motor recovery, 11 (68.8%) maintained their original phenotype, while the rest transitioned to the complete (18.8%) or to another incomplete form (12.5%) due to involvement of previously unaffected segments. Subjects with incomplete typical CIDP had milder pre-treatment disability and weakness compared to those with the complete form, while other clinical and electrodiagnostic features were comparable. As opposed to the complete form, disability in incomplete typical CIDP at diagnosis showed no correlation with muscle strength.

Discussion:
Incomplete forms were observed in nearly one-third of subjects with typical CIDP. Incomplete typical CIDP represents a milder form of complete typical CIDP; however, its other disease characteristics, including treatment response, are similar, highlighting the importance of its proper prompt recognition as CIDP. Impairments beyond motor weakness, such as more diffuse proprioceptive loss, might play a role in the disability of patients with incomplete typical forms of CIDP.