Polyneuropathies and chronic inflammatory demyelinating polyradiculoneuropathy in multiple sclerosis

Area of Science:

• Neurology
• Immunology
• Clinical Medicine

Background:

• Polyneuropathies frequently coexist with multiple sclerosis (MS), potentially exacerbating disability.
• These co-occurring conditions are often underdiagnosed, hindering timely and appropriate patient management.

Purpose of the Study:

• To identify the prevalence and types of polyneuropathies in patients with MS.
• To compare the clinical and electrophysiological characteristics of MS with chronic inflammatory demyelinating polyradiculoneuropathy (MS-CIDP) against MS with other non-inflammatory polyneuropathies.

Main Methods:

• A retrospective chart review was conducted on patients diagnosed with both MS and polyneuropathy at the Mayo Clinic.
• Serum samples from MS-CIDP patients were analyzed for IgG autoantibodies targeting neurofascin-155.

Main Results:

• 133 cases of MS with co-occurring polyneuropathy were identified between 1980-2013.
• Inflammatory neuropathies, including CIDP, were observed in 28 cases, while 15 had inherited neuropathies and 32 had diabetic sensorimotor polyneuropathy.
• MS-CIDP cases exhibited distinct features, such as absent ankle reflexes, earlier neuropathy onset, greater impairment, and specific electrophysiological findings, with a subset showing IgG4 autoantibodies to neurofascin-155.

Conclusions:

• Polyneuropathies significantly contribute to the neurological disability experienced by MS patients.
• The diagnosis of polyneuropathy in MS patients is challenging and likely underreported, emphasizing the need for increased recognition, especially for treatable conditions like CIDP.
• The increased incidence of inflammatory neuropathy, particularly CIDP, in MS suggests a potential shared autoimmune pathogenesis, further supported by the presence of neurofascin-155 autoantibodies.