Differences between Acute-onset Chronic Inflammatory Demyelinating Polyneuropathy (A-CIDP) and Acute Inflammatory Demyelinating Polyneuropathy (AIDP) in adult patients. (P1.436)

Objective: The aim of this study is to find predicting factors that allow differentiating A-CIDP from AIDP at early stages. Background: Acute Inflammatory Demyelinating Polyneuropathy (AIDP) and Acute-onset Chronic Inflammatory Demyelinating Polyneuropathy (A-CIDP) present with similar clinical features within the first 4 weeks, although the latter can progress after 8 weeks. Design/Methods: Clinical records of adult patients (> 18 years old) with AIDP and A-CIDP were reviewed retrospectively from January-2006 to July-2017. The demographic features, clinical manifestations, cerebrospinal-fluid (CSF) features, therapy related to these conditions and clinical evolution were analyzed. Nerve conduction studies were performed in all patients with a follow-up of more than 1 year. Parametric and nonparametric statistical tests were used to compare both groups. Results: Ninety-four patients were included (AIDP, n=80; A-CIDP, n=14). The median age of A-CIDP group was higher (55.5 vs. 42.5 years; p=0.04 ). Diabetes mellitus was more frequent in A-CIDP group (29% vs. 7.5%; p=0.039 ). There were no significant differences in frequency of HIV status, autoimmune and oncologic diseases; the involvement of cranial, motor, sensitive and autonomic nerves were similar in both groups. Among A-CIDP group, we observed a higher tendency of proprioceptive disturbances (55% vs. 29%; p=0.08 ), sensory ataxia (38% vs. 16%; p=0.06 ), albumin-cytological dissociation (93% vs. 73%; p=0.098 ) and CSF-protein level (114.5mg/dl vs. 79.8mg/dl; p=0.067 ). Combined immunotherapy was more frequent in A-CIDP group (29% vs. 2.5%; p=0.004 ). There were no significant differences in ICU admission and mortality. Eleven patients with A-CIDP had a chronic course. Conclusions: Although most of demographic and clinical features were similar in both groups; patients with A-CIDP were older, had more frequency of diabetes mellitus and a higher tendency of proprioceptive disturbances and elevated CSF-protein level. It is important to distinguish both entities, since patients with A-CIDP have a chronic course and require combined immunotherapy frequently. Disclosure: Dr. Alessandro has nothing to disclose. Dr. Pastor has nothing to disclose. Dr. Wilken has nothing to disclose. Dr. Querol has nothing to disclose. Dr Marrodan has nothing to disclose. Dr Marrodan has nothing to disclose. Dr. Rivero has nothing to disclose. Dr. Barroso has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Pfizer. Dr. Barroso has received research support from Alnylam. Dr. Farez has nothing to disclose.