2021 European Guidelines Improve Diagnosis and Treatment of Chronic Inflammatory Demyelinating Polyradiculoneuropathy Variants

Newly published in the European Journal of Neurology, a study on the 2021 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) guidelines for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) showed that the criteria provided a better characterization of CIDP variants, allowing their distinction from typical CIDP and more appropriate treatments for patients.¹

According to the clinical criteria from the 2021 EAN/PNS guidelines, 245 patients were diagnosed with typical CIDP or a CIDP variant (66%). Investigators identified 106 patients with typical CIDP (29%), 62 distal CIDP (17%), 28 multifocal or focal CIDP (7%), 4 sensory CIDP (1%), 27 sensory-predominant CIDP (7%), 10 motor CIDP (3%), and 8 motor-predominant CIDP (2%). Notably, researchers observed that those with multifocal, distal, and sensory CIDP showed milder impairment and symptoms.

Lead author Alberto De Lorenzo, MD, research fellow in neurology at Humanitas Research Hospital in Milan, Italy, told NeurologyLive®, "Different criteria for the definition of CIDP variants have been proposed in literature but their explicit inclusion in clinical guidelines has only been recently achieved. Our findings support the role of the novel clinical criteria for CIDP variants provided by the EAN/PNS taskforce in identifying disease subtypes with unique clinical, therapeutic, and possibly pathophysiological features."

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In this study, investigators applied the clinical criteria of the 2021 EAN/PNS guidelines for CIDP variants to 369 patients included in the Italian CIDP database who fulfilled the 2021 EAN/PNS electrodiagnostic criteria for the condition. Using the same methodology from a previous study,2 all participants underwent a detailed clinical history that included data on the time of onset, distribution, and progression of signs and symptoms including weakness, sensory symptoms, ataxia, pain, cramps, tremor, fatigue, and cranial nerve impairment. Also, results of diagnostic nerve conduction studies (NCS) performed during the disease as part of routine clinical care were included. The findings from previously performed examinations, including cerebrospinal fluid (CSF) analysis and sural nerve biopsy, if available, were also included in the analysis.

In the analysis, investigators reported that patients with multifocal CIDP demonstrated less frequently reduced conduction velocity (14%) and prolonged F-wave latency (4%). Additionally, patients with multifocal CIDP also exhibited lower levels of CSF protein (55%). The patients who had distal CIDP displayed a more frequent reduction of distal compound muscle action potentials (39%). Although participants with motor CIDP did not improve after steroid therapy (0%), those with motor-predominant CIDP did show improvement (100%). Authors noted that despite not one of the patients with sensory CIDP responded to steroids (0%), most of those with sensory-predominant CIDP did show a response (73%).

"The most notable results apply to multifocal CIDP patients, since they shows distinctive electrophysiological features and a less satisfactory response to intravenous immunoglobulins. Furthermore, electrodiagnostic distinction of motor and sensory CIDP from their motor and sensory – predominant counterparts identify steroid-resistant cases and may help in designing tailored treatment strategies," De Lorenzo told.

All told, limitations of the study included the retrospective nature of the data because of possible selection bias particularly with nontypical cases, and lack of standardization in the conduction of NCS. In addition, the majority of the patients included in the database were enrolled prior to the publication of the 2021 EAN/PNS criteria in which authors noted that response to treatment was only confirmed using an impairment or a disability measure. Furthermore, investigators noted that multiple testing correction was not applied because of the exploratory nature of the study and the relatively reduced sample size in CIDP variant subgroups.

"Our work took advantage of the big effort of the Italian CIDP database with its about 700 patients, but, surely, further studies are needed to characterize rare CIDP variants," coauthor Giuseppe Liberatore, MD, assistant in Neuromuscular and Neuroimmunology Service at Humanitas Clinical and Research Institute in Milan, Italy, added. "The new diagnostic criteria were the first step to point out the distinguishing features of CIDP variants, but we think that translational research dedicated specifically to CIDP variants is needed to advance our comprehension of the pathophysiology underlying these subtypes."

REFERENCES
1. De Lorenzo A, Liberatore G, Doneddu PE, et al. Impact of 2021 European Academy of Neurology/Peripheral Nerve Society diagnostic criteria on diagnosis and therapy of chronic inflammatory demyelinating polyradiculoneuropathy variants. Eur J Neurol. Published online January 2, 2024. doi:10.1111/ene.16190
2. Doneddu PE, Cocito D, Manganelli F, et al. Atypical CIDP: diagnostic criteria, progression and treatment response. Data from the Italian CIDP Database. J Neurol Neurosurg Psychiatry. 2019;90(2):125-132. doi:10.1136/jnnp-2018-318714