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Science News: CIDP: Five New Things

Submitted by:  Niranjan Singh, MD
Edited by: Vishwajit Hegde, MD

Karam C. Chronic inflammatory demyelinating polyradiculoneuropathy: Five new things. Neurol Clin Pract. 2022;12(3):258-262. doi:10.1212/CPJ.0000000000001150

Summary: Chronic inflammatory demyelinating Polyradiculoneuropathy (CIDP) is one of the most common autoimmune neuropathies. The disease is heterogeneous with atypical case and evolving immunomodulation therapy. There are several recent developments in CIDP. This article brings us five take-home points:
1. Classification of CIDP The European Federation of Neurological Societies/Peripheral Nerve Society (PNS) CIDP criteria was revised in 2021 and classified CIDP into typical and variant CIDP; atypical CIDP was dropped. CIDP variants included distal CIDP, multi focal CIDP, focal CIDP, motor CIDP, motor predominant CIDP, sensory CIDP and sensory predominant CIDP. Similarly, autoimmune nodopathy are no longer considered part of CIDP. Electrodiagnostic criteria are now classified in to supportive of CIDP and possible CIDP.
Typical CIDP will have evidence of primary demyelination in at least 2 motor nerves and sensory conduction abnormality in 2 nerves. The possible CIDP patients may not meet electrodiagnostic criteria but may have ultrasound or MRA abnormality, cerebrospinal fluid (CSF) protein elevation, pathology on nerve biopsy.
2. The CIDP-CISP Relation: Chronic immune sensory polyradiculopathy (CISP) was initially included as atypical CIDP in 2010 but in 2021 no longer considered CIDP. These patients had chronic sensory ataxia with normal nerve conduction studies and abnormal somatosensory evoked potentials, enlarged nerve roots, elevated CSF protein, and inflammatory hypertrophic changes in sensory nerve roots. Patient who has additional mild distal weakness and mild abnormality in nerve conduction study are now referred as CISP. These patients respond to immune modulating drugs typically use for CIDP.
3. Current therapy of CIDP Both steroid and intravenous immunoglobulin (IVIG) remained the 1st line of treatment and preferred over plasma exchange. Cyclophosphamide, cyclosporine, or rituximab can be considered in refractory patient. CellCept, azathioprine, and cyclosporine may be considered as immunoglobulin or cortical steroid sparing agents. subcutaneous immunoglobulin (SCIG) has been found effective in CIDP and can be given weekly. Less treatment related side effects including less fluctuation. 2021 guidelines suggest 1:1 does conversion. 0.2 gram/kilogram per week and 0.4 grams/kilogram per week both were found to be effective.
4. Antibodies and Serum Neurofilament Light Chain Now autoimmune nodopathy consisting of antibodies directed against proteins located at or around the node of ranvier , neurofascin- anti NF155, anti NF 140/186, Contactin-CNTN1 have been described. These antibodies are rare and seen in less than 5% of patients diagnosed with CIDP. Now this entity is separate from CIDP. They have a different pathology, acute onset, no evidence of inflammation or demyelination, and poor response to IVIG. Serum neurofilament light chain level sNfL can be used as a biomarkers of disease activity in CIDP though more studies are needed.
5. Mimics of CIDP These are rare and mostly due to over interpretation of CSF and electrodiagnostic findings.
Comments: This article provides a nice summary on CIDP depicting diagnosis of CIDP and a spectrum including CIDP variants, atypical CIDP, nodopathy, CISP, diagnostic features including use fullness of EMG and ancillary testing, CSF studies and protein, treatment response from IVIG, steroids, subcutaneous IVIG, use of rituximab in refractory cases, and over diagnosis. This article is very useful for diagnostic and therapeutic purposes. Classification of CIDP is very important in clinical management.
Articles of Similar Interest:
Broers MC, Bunschoten C, Drenthen J, Beck TAO, Brusse E, Lingsma HF, et al. Misdiagnosis and diagnostic pitfalls of chronic inflammatory demyelinating polyradiculoneuropathy. Eur J Neurol. 2021 Jun;28(6):2065-73
Van den Bergh, P. Y. K., van Doorn PA, Hadden RDM, Avau B, Vankrunkelsven P, Allen JA, et al. European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of chronic inflammatory demyelinating polyradiculoneuropathy: Report of a joint Task Force-Second revision. Eur J Neurol. 2021;26(3):242-268

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