Aetiology

There are no clearly defined genetic or environmental risk factors.[2]​ Infection, immunisation, or surgical procedures precede CIDP in approximately 10% to 30% of patients.​[4][6]​​[17]​​​​ There is an increased incidence of CIDP in patients with diabetes mellitus, and severity of CIDP may be worse in these patients.​​[18][19][20]​​​​​ CIDP can also occur in association with infection, including HIV.​​​[19][20] About 10% to 15% of patients have a benign monoclonal gammopathy of undetermined significance (MGUS), most often with an IgA or IgG paraprotein; MGUS may affect disease course and response to treatment.​​​[2][19][20] CIDP may also co-exist with other autoimmune diseases, such as systemic lupus erythematosus, connective tissue disease, inflammatory bowel disease, thyroid disease, sarcoidosis, glomerulonephritis, chronic active hepatitis, or graft-versus-host disease.[19][20]

Pathophysiology

Evidence suggests that CIDP is an autoimmune disease directed against peripheral nerve myelin. Nerve biopsies from patients with CIDP suggest underlying cell-mediated immunity as a mechanism of disease. Endoneurial infiltrates consist mainly of CD4+ and CD8+ T cells and macrophages.[21][22]​​ Immunoglobulin and complement have been immunolocalised to myelin sheaths of affected nerves, and a variety of cytokines, chemokines, co-stimulatory molecules, adhesion molecules, growth factors, and transcription factors are up-regulated in biopsies from patients with CIDP.​​​​[2]​ Humoral immunity also probably plays a role (especially given the discovery of disease mediated by antiparanodal and antinodal antibodies), but auto-antibodies directed against myelin proteins and lipids, such as gangliosides, sulfatides, galactocerebroside, and myelin protein zero, have been found in only a minority of patients.​​​[2]

Classification

European Academy of Neurology/Peripheral Nerve Society (EAN/PNS)[1]

The 2021 EAN/PNS guideline defines two levels of diagnostic certainty for CIDP:[1]

  • CIDP

  • Possible CIDP.

The most common presentation is typical CIDP.[1][2]

CIDP variants are:[1]

  • Distal CIDP (also known as distal acquired demyelinating symmetrical neuropathy)

  • Multifocal CIDP (also known as multifocal demyelinating neuropathy with persistent conduction block, Lewis-Sumner syndrome; multifocal acquired demyelinating sensory and motor neuropathy [MADSAM]; multifocal inflammatory demyelinating neuropathy)

  • Focal CIDP

  • Motor CIDP

  • Motor-predominant CIDP

  • Sensory CIDP

  • Sensory-predominant CIDP.

See Diagnostic criteria.

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