Tips in navigating the diagnostic complexities of chronic inflammatory demyelinating polyradiculoneuropathy

Diagnosis of hereditary transthyretin amyloidosis in patients with suspected chronic inflammatory demyelinating polyneuropathy unresponsive to intravenous immunoglobulins: results of a retrospective study

BACKGROUND AND AIMS

Hereditary transthyretin amyloidosis (ATTRv) should be considered in patients diagnosed with intravenous immunoglobulin (IVIg)-resistant chronic inflammatory demyelinating polyradiculoneuropathy (IVIg-NR CIDP). In this 1-year long, retrospective, multicentric study, an online questionnaire was sent to 1100 French healthcare professionals (HCPs) investigating: (i) how many IVIg-NR CIDP patients they followed; (ii) how many IVIg-NR CIDP patients had undergone TTR gene analysis; and (iii) how many IVIg-NR CIDP patients were eventually diagnosed with ATTRv. The questionnaire was sent every 3 months for 1 year and contained information on ATTRv clinical manifestations and diagnosis.

RESULTS

One-hundred and ten (10%) HCPs responded. A total of 2131 patients with CIDP were identified, including 315 (22.1%) with IVIg-NR CIDP. TTR gene analysis was performed in 144 patients and was positive in 43 cases (29.9%).

CONCLUSIONS

This study demonstrates that ATTRv should be investigated systematically in patients diagnosed with IVIg-NR CIDP. HCP-directed information campaigns are useful for modifying diagnostic practices.

Distinguishing Chronic Inflammatory Demyelinating Polyneuropathy From Mimic Disorders: The Role of Statistical Modeling

BACKGROUND AND AIMS

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is difficult to distinguish from mimicking disorders, with misdiagnosis resulting in IVIG overutilization. We evaluate a clinical-electrophysiological model to facilitate CIDP versus mimic neuropathy prediction.

METHODS

Using the European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) 2021 CIDP guidelines we derived 26 clinical and 144 nerve conduction variables. The model was generated and validated utilizing total CIDP (n = 129) and mimics (n = 309); including (1) IgG4-nodopathies; (2) POEMS (polyneuropathy-organomegaly-endocrinopathy-monoclonal protein-skin changes); (3) anti-myelin-associated-glycoprotein; (4) paraneoplastic; (5) Waldenström B-cell lymphoma; (6) diabetic neuropathies; (7) amyloidosis; (8) Charcot-Marie-Tooth; (9) motor neuropathies/neuronopathies; and (10) idiopathic-inflammatory-myopathies.

RESULTS

We analyzed 9282 clinical and 51 408 electrophysiological data points. Univariate analysis identified 11 of 26 clinical variables with significant odds ratios. A multivariate regression model using four clinical and two electrophysiologic variables achieved 93% area-under-curve (95% CI 91-95): progression over 8 weeks (OR 40.66, 95% CI 5.31-311.36), absent autonomic involvement (OR 17.82, 95% CI 2.93-108.24), absent muscle atrophy (OR 16.65, 95% CI 3.27-84.73), proximal weakness (OR 3.63, 95% CI 1.58-8.33), ulnar motor conduction velocity slowing < 35.7 m/s (OR 5.21, 95% CI 2.13-12.76), and ulnar motor conduction block (OR 13.37, 95% CI 2.47-72.40). A web-based probability calculator (https://news.mayocliniclabs.com/cidp-calculator/) was developed, with 100% sensitivity and 68% specificity at a 92% probability threshold. Specificity improved to 93% when considering "red flags," electrophysiologic criteria, and laboratory testing.

INTERPRETATION

A probability calculator using clinical electrophysiological variables assists CIDP differentiation from mimics, with scores below 92% unlikely to have CIDP. The highest specificity is achieved by considering clinical "red flags," electrophysiologic demyelination, and laboratory testing.

Chronic Inflammatory Demyelinating Polyneuropathy: A Narrative Review of a Systematic Diagnostic Approach to Avoid Misdiagnosis

Chronic inflammatory demyelination polyradiculoneuropathy (CIDP) is a rare autoimmune neuropathy generated by cellular and humoral immune responses. Its course can be chronic, progressive, monophasic, or relapsing-remitting. Misdiagnosis and inappropriate therapy are common in CIDP. Given the scarcity of integrative information, we aimed to briefly summarize the epidemiology, pathophysiology, clinical phenotypes, diagnostic tools, and diagnostic criteria and provide a systematic diagnostic approach. We reviewed articles on Medline (PubMed) from 2018 to 2023, using Google Scholar to summarize the topics. The results are presented as a narrative review, in accordance with recommendations of the Scale for the Assessment of Narrative Review Articles (SANRA) guidelines. The included evidence showed that CIDP is a challenging neuropathy to diagnose and treat. Pathologic factors initiating typical CIDP and atypical CIDP are still clearly unknown. CIDP is diagnosed using the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) criteria, which combine clinical features with electrophysiological evidence of demyelination. However, some patients need to fulfill the requirements. Another challenge is monitoring the disease progression and recognizing patients who do not respond to evidence-based first-line therapy to individualize their treatment. Based on the evidence, we conclude that 2021 EFNS/PNS guidelines allow for a more accurate diagnosis and treatment of CIDP and its variants. New diagnostic tools and molecular approaches are helpful in the diagnosis process but cannot replace clinical and electrodiagnostic criteria.

Serum glycobiomarkers for chronic inflammatory demyelinating polyneuropathy

BACKGROUND

This study conducted a comprehensive glycan analysis of serum to determine how glycan biomarkers are associated with the pathophysiology of chronic inflammatory demyelinating polyneuropathy (CIDP) and the effects of its treatment.

METHODS

We comparatively analyzed N- and O-glycans in the pretreatment serum of 27 treatment-naïve patients with typical CIDP and 20 age- and sex-matched healthy controls (HC) using mass spectrometry. We determined the association between clinical parameters and glycans. The serum glycan and neurofilament light-chain (NfL) levels were assessed at the baseline, and treatment response was defined according to the degree of improvement in the modified Rankin scale 12 weeks after the first dose of intravenous immunoglobulin (IVIg).

RESULTS

Compared with the HC, the CIDP group demonstrated significantly lower levels of serum total N-glycans (CIDP, median 973.3 [IQR 836.2-1131.3] pmol/μL; HC, 1125.0 [1005.0-1236.2] pmol/μL; p < 0.05), especially sialylated N-glycans (CIDP, 898.0 [752.2-1037.2] pmol/μL; HC, 1064.4 [942.7-1189.8] pmol/μL; p < 0.01). In contrast, the O-glycan levels did not differ significantly between the two groups. The treatment response was associated with low N-glycan levels, but not with the serum NfL levels. Low levels of sialylated N-glycans were associated with resistance to treatment over 12 weeks, with an area under the curve of 0.822 (p < 0.01).

CONCLUSIONS

Low levels of sialylated N-glycans could potentially serve as a novel biomarker, reflecting pathophysiology and therapeutic resistance in typical CIDP.

New chronic inflammatory demyelinating polyneuropathy/Guillain-Barré syndrome guidelines - impact on clinical practise

PURPOSE OF REVIEW

There is no diagnostic biomarker that can reliably detect Guillain-Barré syndrome (GBS) or chronic inflammatory demyelinating polyneuropathy (CIDP). Diagnosis relies upon integrating key clinical characteristics and relevant supportive data. Consequently, misdiagnosis and delayed diagnosis are common. Diagnostic criteria have proven valuable resources to improve diagnosis, but are underutilized during routine clinical care.

RECENT FINDINGS

In 2021, the EAN/PNS CIDP criteria was published, and were followed by the EAN/PNS GBS criteria in 2023. Both guidelines utilized GRADE methodology to formulate evidence-based recommendations that are intended to be used by adult and paediatric clinicians across diverse care settings to optimize diagnostic accuracy and improve patient outcomes during routine clinical care.

SUMMARY

The EAN/PNS GBS and CIDP criteria detail specific clinical, electrophysiological, and laboratory features that raise diagnostic confidence, and call attention to diagnostic mimics. The sensitivity of EAN/PNS and other modern criteria to detect GBS and CIDP is high, but utilization during clinical practice is low. Complexity is one factor limiting widespread application. Strategies are needed to optimize criteria adoption during routine clinical care such that GBS and CIDP diagnosis can be achieved with greater speed and accuracy.

Genetic analyses of inflammatory polyneuropathy and chronic inflammatory demyelinating polyradiculoneuropathy identified candidate genes

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare, immune-mediated disorder in which an aberrant immune response causes demyelination and axonal damage of the peripheral nerves. Genetic contribution to CIDP is unclear and no genome-wide association study (GWAS) has been reported so far. In this study, we aimed to identify CIDP-related risk loci, genes, and pathways. We first focused on CIDP, and 516 CIDP cases and 403,545 controls were included in the GWAS analysis. We also investigated genetic risk for inflammatory polyneuropathy (IP), in which we performed a GWAS study using FinnGen data and combined the results with GWAS from the UK Biobank using a fixed-effect meta-analysis. A total of 1,261 IP cases and 823,730 controls were included in the analysis. Stratified analyses by gender were performed. Mendelian randomization (MR), colocalization, and transcriptome-wide association study (TWAS) analyses were performed to identify associated genes. Gene-set analyses were conducted to identify associated pathways. We identified one genome-wide significant locus at 20q13.33 for CIDP risk among women, the top variant located at the intron region of gene CDH4. Sex-combined MR, colocalization, and TWAS analyses identified three candidate pathogenic genes for CIDP and five genes for IP. MAGMA gene-set analyses identified a total of 18 pathways related to IP or CIDP. Sex-stratified analyses identified three genes for IP among males and two genes for IP among females. Our study identified suggestive risk genes and pathways for CIDP and IP. Functional analyses should be conducted to further confirm these associations.

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.