Prognostic value of nerve ultrasonography: A prospective multicenter study on the natural history of chronic inflammatory neuropathies

Typical CIDP, distal variant CIDP, and anti-MAG antibody neuropathy: An ultra-high frequency ultrasound comparison of nerve structure

To date, little is known about the usefulness of ultra-high frequency ultrasound (UHF-US, 50-70 MHz) in clinical practice for the diagnosis of dysimmune neuropathies. We present a prospective study aimed at comparing UHF-US alterations of nerves and fascicles in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), distal CIDP (d-CIDP) and anti-MAG neuropathy and their relationships with clinical and electrodiagnostic (EDX) features. 28 patients were included (twelve CIDP, 6 d-CIDP and 10 anti-MAG) and ten healthy controls. Each patient underwent neurological examination, EDX and UHF-US study of median and ulnar nerves bilaterally. UHF-US was reliable in differentiating immune neuropathies from controls when using mean and/or segmental nerve and/or fascicle cross-sectional area (CSA); furthermore, fascicle ratio (fascicle/nerve CSA) was a reliable factor for differentiating d-CIDP from other types of polyneuropathies. The fascicle CSA appears to be more increased in CIDP and its variant than in anti-MAG neuropathy. UHF-US offers information beyond simple nerve CSA and allows for a better characterization of the different forms of dysimmune neuropathies.

The distribution pattern of nerve enlargement in clinical subtypes of chronic inflammatory demyelinating polyneuropathy

BACKGROUND AND PURPOSE

We aim to investigate nerve enlargement patterns and their correlation with clinical subtypes and treatment response using nerve ultrasound in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

Between March 2015 and December 2021, 135 CIDP patients were recruited. Nerve ultrasound and electrophysiological studies were performed on the median and ulnar nerves. The responses to intravenous immunoglobulin (IVIg) or prednisone were evaluated with the disability score.

RESULTS

There were 99 typical CIDP cases, 10 Lewis-Sumner syndrome (LSS) cases, 15 distal acquired demyelinating symmetric neuropathy (DADS) cases, nine pure motor CIDP cases, and two pure sensory CIDP cases. Sixty (61%) typical CIDP and seven (78%) pure motor CIDP patients had moderately increased or normal cross-sectional area (CSA), and 10 (67%) DADS and seven (70%) LSS patients had significantly increased CSA. The peripheral nerve showed a diffuse enlargement pattern in 46 (51%) typical CIDP, five (50%) LSS, three (25%) DADS, and three (33%) pure motor CIDP patients and a proximal regional enlargement pattern in 11 (12%) typical CIDP, one (10%) LSS, six (50%) DADS, and four (44%) pure motor CIDP patients. Patients with diffusely moderate enlargement patterns and those with proximal regional enlargement showed a higher response rate to glucocorticoids than to IVIg.

CONCLUSIONS

Various distribution patterns of nerve enlargement existed in CIDP. Although almost all patterns could be detected in each CIDP subtype, diffusely moderate enlargement was more common in typical CIDP and LSS, while proximal regional enlargement was more common in DADS and pure motor CIDP. Different enlargement patterns might indicate different treatment responses.

Sex differences in Guillain Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy and experimental autoimmune neuritis

Guillain Barré syndrome (GBS) and its variants, and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP and its variants, are regarded as immune mediated neuropathies. Unlike in many autoimmune disorders, GBS and CIDP are more common in males than females. Sex is not a clear predictor of outcome. Experimental autoimmune neuritis (EAN) is an animal model of these diseases, but there are no studies of the effects of sex in EAN. The pathogenesis of GBS and CIDP involves immune response to non-protein antigens, antigen presentation through non-conventional T cells and, in CIDP with nodopathy, IgG4 antibody responses to antigens. There are some reported sex differences in some of these elements of the immune system and we speculate that these sex differences could contribute to the male predominance of these diseases, and suggest that sex differences in peripheral nerves is a topic worthy of further study.

Fluid Biomarkers for Monitoring Structural Changes in Polyneuropathies: Their Use in Clinical Practice and Trials

Reliable and responsive tools for monitoring disease activity and treatment outcomes in patients with neuropathies are lacking. With the emergence of ultrasensitive blood bioassays, proteins released with nerve damage are potentially useful response biomarkers for many neurological disorders, including polyneuropathies. In this review, we provide an overview of the existing literature focusing on potential applications in polyneuropathy clinical care and trials. Whilst several promising candidates have been identified, no studies have investigated if any of these proteins can serve as response biomarkers of longitudinal disease activity, except for neurofilament light (NfL). For NfL, limited evidence exists supporting a role as a response biomarker in Guillain-Barré syndrome, vasculitic neuropathy, and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Most evidence exists for NfL as a response biomarker in hereditary transthyretin-related amyloidosis (hATTR). At the present time, the role of NfL is therefore limited to a supporting clinical tool or exploratory endpoint in trials. Future developments will need to focus on the discovery of additional biomarkers for anatomically specific and other forms of nerve damage using high-throughput technologies and highly sensitive analytical platforms in adequality powered studies of appropriate design. For NfL, a better understanding of cut-off values, the relation to clinical symptoms and long-term disability as well as dynamics in serum on and off treatment is needed to further expand and proceed towards implementation.