Comparison of the diagnostic accuracy of the 2021 EAN/PNS and 2010 EFNS/PNS diagnostic criteria for chronic inflammatory demyelinating polyradiculoneuropathy

The overlap of diabetic and inflammatory neuropathies: Epidemiology, possible mechanisms, and treatment implications

Diabetic polyneuropathy is the common neuropathy of diabetes. However, several inflammatory neuropathies may occur during diabetes. Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) represents the most treatable example. There has been uncertainty about a higher risk of CIDP in subjects with diabetes. Contradicting earlier reports, subsequent epidemiological studies failed to confirm an association. However, more recent studies from different populations have shown a two-fold relative risk of concurrent diabetes with CIDP. Recognition of CIDP is important in diabetes as treatment response rates have been reported as comparable with or without diabetes. However, with diabetes, the clinical presentation of CIDP and the resulting disability may be more severe due to additional axonal loss from pre-existing diabetic polyneuropathy and delayed diagnosis. An association of nodo-paranodopathy has similarly been described with a three-fold relative risk of concurrent diabetes in seropositive subjects, particularly those harbouring anti-contactin 1 antibodies. Although rare, recognition of nodo-paranodopathy, with characteristic clinical features, in the context of diabetes is likewise important in view of treatment implications. Other inflammatory neuropathies in diabetes are the painful or painless, cervical, or lumbar, radiculoplexus neuropathies. These need distinguishing from variant, multifocal forms of CIDP, as are not treatable, although remit spontaneously over months or years. There are reports of possible association of Guillain-Barré syndrome (GBS), and particularly of greater GBS severity, with diabetes. Finally, vasculitic neuropathy may also occur in diabetes and requires early suspicion, urgent investigations and immunosuppressant treatment. As the worldwide prevalence of diabetes rises, prompt recognition of its concurrent inflammatory neuropathies, is essential.

Novel therapies in CIDP

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a heterogeneous but clinically well-described disease within circumscribed parameters. It is immunologically mediated through several poorly understood mechanisms. First-line therapies with steroids, intravenous immunoglobulin (IVIG) or plasma exchange are each effective in about two-thirds of patients. These treatments are seldom associated with complete resolution or cure, and often pose considerable practical, financial and medical implications.Our understanding of many of the key pathological processes in autoimmune diseases is expanding, and novel targeted therapeutics are being developed with promise in several autoimmune neurological disorders.This narrative review looks first at detailing key pathogenic mechanisms of disease in CIDP, followed by an in-depth description of potential novel therapies and the current evidence of their application in clinical practice.

Diagnostic criteria and therapeutic implications of rapid-onset demyelinating polyneuropathies

Guillain-Barré syndrome (GBS) and acute-onset chronic inflammatory demyelinating polyneuropathy (A-CIDP) are the most common autoimmune polyneuropathies. Their aetiology is unclear. The pathomechanism includes damage mainly to the myelin sheath and, in the long-term process, secondary axonal loss. Both inflammatory polyneuropathies involve different combinations of motor, sensory and autonomic fibres in the peripheral nerves. The differential diagnosis should be based on clinical and neurophysiological features, and laboratory tests. Numerous studies aim to demonstrate the most common errors in the diagnosis of Guillain-Barré syndrome and acute-onset CIDP. Misdiagnosis can result in the wrong treatment. We still do not have reliable markers to help diagnose the disease or to monitor the effectiveness of the therapy.

Characteristics and outcome of chronic inflammatory demyelinating polyradiculoneuropathy patients according to their diagnostic certainty based on the 2021 EAN/PNS criteria

INTRODUCTION

To describe the clinical characteristics and long term outcome of CIDP patients according to 2021 EAN/PNS diagnostic certainty categories.

METHODS

We reviewed clinical data, response to treatment, cerebrospinal fluid examination, and nerve conduction studies parameters of 39 adult "CIDP" and 24 "possible CIDP" patients. Data were collected at diagnosis and after one (T1), two (T2), three (T3) and five years (T5).

RESULTS

At diagnosis, "possible CIDP" patients' phenotypes were more atypical (especially focal/multifocal, p < .01) and "CIDP" patients had a higher NIS and INCAT scores (p = .08 and 0.08). Compared to baseline: median NIS score decreased in "CIDP" and was stable in "possible CIDP" patients at T1 (p < .05), T2 (p < .05) and T3 (p < .01); median MRC score slightly increased in "CIDP" and was stable in "possible CIDP" patients at T2 (p < .05); and INCAT disability scale slightly decreased in "CIDP" and was stable in "possible CIDP" patients at T3 (p < .05). The proportion of moderate to severely disabled (mRS > 2) patients in "possible CIDP" group was higher than in "CIDP" group (not significant). "CIDP" patients had a better objective response to immunotherapy (59 % responders) than "possible CIDP" patients (29 % responders, p < .05), especially among typical CIDP patients (86 % of responders in "CIDP" versus 33 % of responders in "possible CIDP" patients, p < .05).

CONCLUSION

"CIDP" patients had a more severe neuropathy, estimated with the NIS and INCAT scores, and "possible CIDP" patients had a more atypical phenotype at baseline. Our data suggest that long-term patient outcome and response to immunotherapy is better in "CIDP" than "possible CIDP".

Whole-body magnetic resonance neurography in patients with chronic inflammatory demyelinating polyneuropathy

INTRODUCTION/AIMS

Whole-body magnetic resonance neurography (MRN) is an imaging modality that shows peripheral nerve signal change in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). We aimed to explore the diagnostic potential of whole-body MRN and its potential as a monitoring tool after immunotherapy in treatment-naïve CIDP patients.

METHODS

Whole-body MRN using coronal 3-dimensional short tau inversion recovery (STIR) sampling perfection with application-optimized contrasts by using different flip angle evolution (SPACE) techniques was performed in patients being investigated for CIDP and in healthy controls. Baseline clinical neuropathy scales and electrophysiologic parameters were collected, and MRN findings were compared before and after CIDP treatment.

RESULTS

We found highly concordant symmetrical thickening and increased T2 signal intensities in the brachial/lumbosacral plexus, femoral, or sciatic nerves in five of the eight patients with a final diagnosis of CIDP and none of the healthy controls. There were no treatment-related imaging changes in five patients with CIDP who completed a follow-up study. Diffuse, symmetrical thickening, and increased T2 signal in root, plexus, and peripheral nerves were found in two patients ultimately excluded due to a diagnosis of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) syndrome in addition to signal changes in the muscles, bony lesions, organomegaly, and lymphadenopathy.

DISCUSSION

Whole-body MRN imaging shows promise in detecting abnormalities in proximal nerve segments in patients with CIDP. Future studies evaluating the role of MRN in assessing treatment response should consider follow-up scans after treatment durations of more than 4 months.

Impact of 2021 European Academy of Neurology/Peripheral Nerve Society diagnostic criteria on diagnosis and therapy of chronic inflammatory demyelinating polyradiculoneuropathy variants

BACKGROUND AND PURPOSE

There are different criteria for the diagnosis of different variants of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The 2021 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) guidelines provide specific clinical criteria for each CIDP variant even if their therapeutical impact has not been investigated.

METHODS

We applied the clinical criteria for CIDP variants of the 2021 EAN/PNS guidelines to 369 patients included in the Italian CIDP database who fulfilled the 2021 EAN/PNS electrodiagnostic criteria for CIDP.

RESULTS

According to the 2021 EAN/PNS clinical criteria, 245 patients achieved a clinical diagnosis of typical CIDP or CIDP variant (66%). We identified 106 patients with typical CIDP (29%), 62 distal CIDP (17%), 28 multifocal or focal CIDP (7%), four sensory CIDP (1%), 27 sensory-predominant CIDP (7%), 10 motor CIDP (3%), and eight motor-predominant CIDP (2%). Patients with multifocal, distal, and sensory CIDP had milder impairment and symptoms. Patients with multifocal CIDP had less frequently reduced conduction velocity and prolonged F-wave latency and had lower levels of cerebrospinal fluid protein. Patients with distal CIDP more frequently had reduced distal compound muscle action potentials. Patients with motor CIDP did not improve after steroid therapy, whereas those with motor-predominant CIDP did. None of the patients with sensory CIDP responded to steroids, whereas most of those with sensory-predominant CIDP did.

CONCLUSIONS

The 2021 EAN/PNS criteria for CIDP allow a better characterization of CIDP variants, permitting their distinction from typical CIDP and more appropriate treatment for patients.

Evaluation of diagnostic yield of the 2021 European Academy of Neurology/Peripheral Nerve Society diagnostic criteria for CIDP

INTRODUCTION/AIMS

It is unclear whether the revised European Academy of Neurology/Peripheral Nerve Society diagnostic criteria (EAN/PNS 2021 criteria) improved the diagnostic yield for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) compared with the previous version. Therefore, this study aimed to compare the sensitivity and specificity of the EAN/PNS 2021 criteria and the European Federation of Neurological Societies/Peripheral Nerve Society 2010 diagnostic criteria (EFNS/PNS 2010 criteria), with a specific focus on the electrodiagnostic criteria.

METHODS

Data of patients with clinically suspected CIDP who exhibited objective treatment response, and of those with chronic axonal neuropathies, obtained between 2009 and 2021, were extracted retrospectively from our database. Patients who underwent nerve conduction studies in at least unilateral upper and lower extremities were enrolled. We compared the sensitivity and specificity of the EAN/PNS 2021 and EFNS/PNS 2010 criteria.

RESULTS

In total, 55 patients with clinically suspected CIDP and 36 patients with chronic axonal neuropathies were enrolled. When considering the "possible CIDP" category, the EAN/PNS 2021 criteria showed lower sensitivity than the EFNS/PNS 2010 criteria (78% vs. 93%, p < .05), whereas its specificity was higher (78% vs. 61%, p < .05). The lower sensitivity was caused mainly by the failure to fulfill the sensory nerve conduction criteria. The revised definition of abnormal temporal dispersion of the tibial nerve contributed markedly to the improved specificity.

DISCUSSION

To improve the sensitivity of the EAN/PNS 2021 criteria, increasing the number of tested sensory nerves may be necessary.

Challenges in the Early Diagnosis and Treatment of Chronic Inflammatory Demyelinating Polyradiculoneuropathy in Adults: Current Perspectives

Diagnosing Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) poses numerous challenges. The heterogeneous presentations of CIDP variants, its mimics, and the complexity of interpreting electrodiagnostic criteria are just a few of the many reasons for misdiagnoses. Early recognition and treatment are important to reduce the risk of irreversible axonal damage, which may lead to permanent disability. The diagnosis of CIDP is based on a combination of clinical symptoms, nerve conduction study findings that indicate demyelination, and other supportive criteria. In 2021, the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) published a revision on the most widely adopted guideline on the diagnosis and treatment of CIDP. This updated guideline now includes clinical and electrodiagnostic criteria for CIDP variants (previously termed atypical CIDP), updated supportive criteria, and sensory criteria as an integral part of the electrodiagnostic criteria. Due to its many rules and exceptions, this guideline is complex and misinterpretation of nerve conduction study findings remain common. CIDP is treatable with intravenous immunoglobulins, corticosteroids, and plasma exchange. The choice of therapy should be tailored to the individual patient's situation, taking into account the severity of symptoms, potential side effects, patient autonomy, and past treatments. Treatment responses should be evaluated as objectively as possible using disability and impairment scales. Applying these outcome measures consistently in clinical practice aids in recognizing the effectiveness (or lack thereof) of a treatment and facilitates timely consideration of alternative diagnoses or treatments. This review provides an overview of the current perspectives on the diagnostic process and first-line treatments for managing the disease.

Impact of social-functioning and sleep on quality of life in chronic inflammatory demyelinating polyneuropathy

INTRODUCTION/AIMS

The impact of impairment of social functioning and sleep on health-related quality of life (HR-QoL), is unknown in chronic inflammatory demyelinating polyneuropathy (CIDP). The value of the Chronic Acquired Polyneuropathy Patient-Reported Index (CAP-PRI) to identify potential social functioning and sleep issues is equally unknown.

METHODS

We performed a cross-sectional evaluation of social functioning and sleep using the "Scales for Outcomes in Parkinson's Disease" (SCOPA) in 40 subjects with clinically-stable CIDP through a structured questionnaire. We assessed HR-QoL through the CAP-PRI. Disability was evaluated through the Overall Neuropathy Limitation Score (ONLS).

RESULTS

SCOPA social functioning scores were impaired at least "a little" per averaged item in > 50 % of subjects, and at least "quite a bit" per averaged item in > 20 %. Most affected items were (i) difficulty with work/household/other chores (ii) difficulties with hobbies/sport/leisure activities. SCOPA sleep sub-scores indicated at least "a little concern" for night-time sleep in nearly 50 % of subjects. Abnormal sleep timing was rare. Associations were found between both SCOPA social-functioning and SCOPA sleep scores and the CAP-PRI. Linear regression demonstrated the SCOPA social-functioning score was independently associated with the CAP-PRI. The CAP-PRI showed high association with disability scores, good internal consistency, absence of ceiling effect, absence of significant floor-effect, and good criteria-related as well as construct-related validity.

DISCUSSION

Social functioning and night-time sleep are frequently affected in CIDP and impact on HR-QoL. In contrast to traditional disability scales, the CAP-PRI additionally allows adequately capturing these impairments and may represent an adequate holistic outcome measure.

Chronic Immune-Mediated Demyelinating Neuropathies

OBJECTIVE

This article is an overview of chronic demyelinating neuropathies and highlights the phenotypic categorization, diagnosis, and treatment of chronic immune-mediated neuropathies. The clinical and diagnostic characteristics of other chronic demyelinating neuropathies that are common mimics of immune-mediated neuropathies are also discussed.

LATEST DEVELOPMENTS

The underlying pathophysiology of chronic demyelinating neuropathies is heterogeneous, and components of both humoral and cellular immune responses are thought to play a role in the immune-mediated types of chronic demyelinating neuropathy. The role of the humoral response is highlighted with a specific focus on the relatively recent discovery of antibody-mediated antinodal and paranodal demyelinating neuropathies. Additionally, new diagnostic criteria for some of the chronic demyelinating neuropathies, as well as ways to differentiate chronic inflammatory demyelinating polyradiculoneuropathy from other chronic demyelinating polyneuropathies, are discussed.

ESSENTIAL POINTS

Chronic demyelinating neuropathies can present with overlapping clinical characteristics with seemingly subtle variations. It is clinically important to differentiate these types of neuropathies because the treatment and management can vary and affect prognosis.

Objectivity, practicality, and significance of practice guidelines for the practicing neurologists: What we learnt from consensus criteria in CIDP, Myasthenia Gravis and Inflammatory Myopathies

The value of practice guidelines in the three most common autoimmune neuromuscular disorders, namely Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), Myasthenia Gravis (MG) and Autoimmune Inflammatory Myopathies (AIM), has been extensively debated regarding their usefulness in clinical practice, objectivity and universal value considering that guidelines are also established regionally in certain countries. This commentary highlights common concerns on how guidelines are presently generated, pointing out: (a) non-sufficient diversity among Task-Force members to identify and address not only routine clinical and electrophysiology issues but also immunology, imaging, pathology, biomarkers, epidemiology or treatment economics; (b) Task-Force being often comprised by the same or seemingly like-minded members conveying the erroneous impression that experts with opposing views might have been excluded, even if this is clearly not the case; and (c) relying on web-based registries or retrospective data collections from heterogeneous sources. As a result, the existing practice guidelines in CIDP, MG and AIM remain an unfinished business but an excellent base for further enhancement. Guidelines can be extremely helpful not only for clinical trials but also in clinical practice if viewed as a living document with continuously updated versions by experts even with opposing views with precise information on diagnostics, pathomechanisms, therapeutic schemes, evolving biomarkers and economics of new therapies with validation of the post-guidelines criteria. Geographic diversity should be taken into consideration because the availability of biomarker testing, and therapies differ among countries. Patient preferences need to be also considered in therapeutic guidelines because newly marketed drugs offer more options steadily changing the therapeutic algorithms in autoimmune neuromuscular diseases generating also questions as to whether they also influence decisions on insurance coverage. Collectively, these startup considerations are aimed to make practice guidelines more objective, widely acceptable worldwide and more practical or easier to follow in clinical practice.

Unclassified clinical presentations of chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

To assess the ability of the 2021 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) clinical criteria for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) to include within their classification the whole spectrum of clinical heterogeneity of the disease and to define the clinical characteristics of the unclassifiable clinical forms.

METHODS

The 2021 EAN/PNS clinical criteria for CIDP were applied to 329 patients fulfilling the electrodiagnostic (and in some cases also the supportive) criteria for the diagnosis of CIDP. Clinical characteristics were reviewed for each patient not strictly fulfilling the clinical criteria ('unclassifiable').

RESULTS

At study inclusion, 124 (37.5%) patients had an unclassifiable clinical presentation, including 110 (89%) with a typical CIDP-like clinical phenotype in whom some segments of the four limbs were unaffected by weakness ('incomplete typical CIDP'), 10 (8%) with a mild distal, symmetric, sensory or sensorimotor polyneuropathy confined to the lower limbs with cranial nerve involvement ('cranial nerve predominant CIDP') and 4 (1%) with a symmetric sensorimotor polyneuropathy limited to the proximal and distal areas of the lower limbs ('paraparetic CIDP'). Eighty-one (65%) patients maintained an unclassifiable presentation during the entire disease follow-up while 13 patients progressed to typical CIDP. Patients with the unclassifiable clinical forms compared with patients with typical CIDP had a milder form of CIDP, while there was no difference in the distribution patterns of demyelination.

CONCLUSIONS

A proportion of patients with CIDP do not strictly fulfil the 2021 EAN/PNS clinical criteria for diagnosis. These unclassifiable clinical phenotypes may pose diagnostic challenges and thus deserve more attention in clinical practice and research.

Molecular, Electrophysiological, and Ultrasonographic Differences in Selected Immune-Mediated Neuropathies with Therapeutic Implications

The spectrum of immune-mediated neuropathies is broad and the different subtypes are still being researched. With the numerous subtypes of immune-mediated neuropathies, establishing the appropriate diagnosis in normal clinical practice is challenging. The treatment of these disorders is also troublesome. The authors have undertaken a literature review of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), Guillain-Barre syndrome (GBS) and multifocal motor neuropathy (MMN). The molecular, electrophysiological and ultrasound features of these autoimmune polyneuropathies are analyzed, highlighting the differences in diagnosis and ultimately treatment. The immune dysfunction can lead to damage to the peripheral nervous system. In practice, it is suspected that these disorders are caused by autoimmunity to proteins located in the node of Ranvier or myelin components of peripheral nerves, although disease-associated autoantibodies have not been identified for all disorders. The electrophysiological presence of conduction blocks is another important factor characterizing separate subgroups of treatment-naive motor neuropathies, including multifocal CIDP (synonyms: multifocal demyelinating neuropathy with persistent conduction block), which differs from multifocal motor neuropathy with conduction block (MMN) in both responses to treatment modalities and electrophysiological features. Ultrasound is a reliable method for diagnosing immune-mediated neuropathies, particularly when alternative diagnostic examinations yield inconclusive results. In overall terms, the management of these disorders includes immunotherapy such as corticosteroids, intravenous immunoglobulin or plasma exchange. Improvements in clinical criteria and the development of more disease-specific immunotherapies should expand the therapeutic possibilities for these debilitating diseases.