Minimal and asymptomatic chronic inflammatory demyelinating polyneuropathy

Atypical chronic inflammatory demyelinating polyradiculoneuropathy: recent advances on classification, diagnosis, and pathogenesis

PURPOSE OF REVIEW

In recent years, there has been an intense debate in literature regarding the definition of the individual variants of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), their possible pathogenetic mechanisms, and impact in the diagnosis of CIDP.

RECENT FINDINGS

The 2021 European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) guidelines revised the definition of the individual CIDP variants and implemented their diagnostic criteria. Diagnosis of atypical CIDP is challenging and misdiagnosis is frequent, leading to diagnostic delay and consequent greater accumulation of disability and treatment dependency. Recent studies suggest that patients with typical CIDP have an antibody-mediated mechanism of neuropathy whereas in those with Lewis--Sumner syndrome (LSS) neuropathy is preferentially mediated by macrophages and T cells.

SUMMARY

Although the validity of the 2021 EFNS/PNS diagnostic criteria for atypical CIDP is unknown, they will hopefully lead to greater uniformity in the selection of patients to be enrolled in future studies and to a greater diagnostic accuracy. New data are emerging on the possible pathological mechanisms of individual variants and this could result in the discovery of specific diagnostic biomarkers and new therapies.

Atypical CIDP: diagnostic criteria, progression and treatment response. Data from the Italian CIDP Database

OBJECTIVES

A few variants of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) have been described, but their frequency and evolution to typical CIDP remain unclear. To determine the frequency and characteristics of the CIDP variants, their possible evolution to typical CIDP, and treatment response.

METHODS

We applied a set of diagnostic criteria to 460 patients included in a database of Italian patients with CIDP. Clinical characteristics and treatment response were reviewed for each patient. The Kaplan-Meier curve was used to estimate the progression rate from atypical to typical CIDP.

RESULTS

At the time of inclusion, 376 (82%) patients had a diagnosis of typical CIDP while 84 (18%) had atypical CIDP, including 34 (7%) with distal acquired demyelinating symmetric neuropathy (DADS), 17 (4%) with purely motor, 17 (4%) with Lewis-Sumner syndrome (LSS) and 16 (3.5%) with purely sensory CIDP. Based on retrospective review of the symptoms and signs present at onset and for at least 1 year, 180 (39%) patients had an initial diagnosis compatible with atypical CIDP that in 96 (53%) patients evolved to typical CIDP. Mean disease duration was longer in patients evolving to typical CIDP than in those not evolving (p=0.0016). Patients with DADS and LSS had a less frequent response to immunoglobulin than those with typical CIDP, while patients with purely motor and sensory CIDP had a similar treatment response.

CONCLUSIONS

The proportion of patients with atypical CIDP varies during the disease course. DADS and LSS have a less frequent response to intravenous immunoglobulin compared with typical CIDP, raising the possibility of a different underlying pathogenetic mechanism.

Chronic inflammatory demyelinating polyradiculoneuropathy and variants: where we are and where we should go

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a chronic and often disabling sensory motor neuropathy postulated as caused by an immune attack against peripheral nerve myelin. In addition to a classic sensory–motor polyneuropathy, other phenotypes of CIDP have been described including the Lewis- Sumner syndrome, distal acquired demyelinating symmetric (DADS) neuropathy, pure motor CIDP, pure sensory CIDP including chronic immune sensory polyradiculopathy (CISP), and focal CIDP. These phenotypes are currently considered to be variants of CIDP, even if the possibility that they represent different demyelinating neuropathies cannot be fully excluded considering differences in their response to therapy. Several data support the role of the immune system in the pathogenesis of CIDP even if the precise targets and actors (antibodies and lymphocytes) of this immune response remain uncertain. Recent studies have shown that the therapeutic response may differ in patients with peculiar clinical presentations supporting the hypothesis that different pathogenetic mechanisms may underlie the heterogeneity of CIDP. The majority of patients with CIDP show improvement after immune therapies including corticosteroids, plasma exchange, and high-dose intravenous immunoglobulin (IVIg). It remains unclear why none of the other immune therapies that were reported to be variably effective in other immune disorders proved to be effective also in CIDP.

Steroid-induced inflammatory neuropathy in a patient on tumor necrosis factor-α antagonist therapy

We describe a patient on the tumor necrosis factor-α antagonist, adalimumab, for 2 years for rheumatoid arthitis, who developed a rapidly progressive inflammatory neuropathy shortly after starting oral steroids. Adalimumab was stopped at onset of neurologic symptoms. Electrophysiology showed demyelination, which persisted at 6 month follow-up, cerebrospinal fluid analysis showed persistent albuminocytologic dissociation, and magnetic resonance studies revealed enlarged and enhancing nerve roots. Treatment with intravenous immunoglobulins resulted in slow, progressive improvement. Tumor necrosis factor-α antagonists have previously been implicated in acquired demyelinating neuropathies. In this patient, we hypothesize that adalimumab may have caused an initially asymptomatic chronic inflammatory demyelinating polyneuropathy, which became symptomatic shortly after initiation of steroid therapy. This case may raise the issue of the safety of steroids in conjunction with antitumor necrosis factor-α therapy in susceptible patients.

A current view of the diagnosis, clinical variants, response to treatment and prognosis of chronic inflammatory demyelinating polyradiculoneuropathy

We retrospectively analyzed 146 patients fulfilling the European Federation of Neurological Societies and the Peripheral Nerve Society (EFNS/PNS) criteria for definite chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) to (1) evaluate the relevance of these criteria, (2) assess the frequency of CIDP variants, and (3) determine the response to treatment and the prognosis. We found that 75% of these patients fulfilled the main EFNS/PNS clinical and electrophysiological criteria (type I). The remaining patients were diagnosed using laboratory tools as supportive criteria. The common form of CIDP represented 51% of patients. We observed a high frequency of the sensory variant (35% of patients) and the rapid onset form (18%). A positive response to treatment was observed in 87% of patients, with a similar efficacy of prednisone and IVIg. However, in the long term, 40% of treated patients remained dependent on treatment. The IVIg dependency rate was higher than the prednisone or plasma exchange dependency rate (55%, 18%, and 23%, respectively; p = 0.0054). Severe handicap was observed in 24% of patients.

Chronic inflammatory demyelinating polyradiculoneuropathy: diagnostic and therapeutic challenges for a treatable condition

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a chronic neuropathy of supposed immune origin. Understanding of its pathophysiology has recently improved, although its causes remain unclear. The classic presentation of CIDP includes sensory and motor symptoms in the distal and proximal segments of the four limbs with areflexia, evolving over more than 8 weeks. Raised protein concentrations in CSF and heterogeneous slowing of nerve conduction are typical of the condition. In addition to this usual phenotype, distribution of symptoms, disease course, and disability can be heterogeneous, leading to underdiagnosis of the disorder. Diagnosis is sometimes challenging and can require use of imaging and nerve biopsy. Steroids and intravenous immunoglobulin are effective, and plasma exchange can be helpful as rescue therapy. The usefulness of immunosuppressants needs to be established. The identification of specific diagnostic markers and new therapeutic strategies with conventional or targeted immunotherapy are needed to improve the outlook for patients with CIDP.

[Diagnostic strategy for chronic inflammatory demyelinating polyradiculoneuropathy. Recommendations of the French working group]

The diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) requires a careful clinical and neurophysiological evaluation, often completed by CSF analysis. In numerous cases, this diagnosis is straightforward and leads to rapid initiation of an immunomodulatory treatment. However, some patients are not diagnosed because of atypical clinical and/or neurophysiological features, and do not benefit from a potentially effective treatment. In this context, a working group was composed with the task of establishing recommendations on diagnostic strategies for CIDP in the main clinical situations where this diagnosis may be suspected. We have summarized these recommendations and tried to present them in the form of a decision-making algorithm.

Recommendations on diagnostic strategies for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune mediated treatable peripheral neuropathy, the diagnosis of which is straightforward in more than half of cases. Numerous sets of electrophysiological criteria have been published. However, in some cases, electrophysiological data are not sufficient and patients that may benefit from treatment escape accurate diagnosis.

OBJECTIVE

To describe a step by step diagnostic procedure for neurologists facing a peripheral neuropathy of undetermined cause, to help make an accurate diagnosis of CIDP.

METHODS

A group of French experts was established, neurologists and neurophysiologists being recruited on the basis of personal experience with patients suffering from CIDP and also on publications in the field. A full literature review was conducted on the topic of diagnostic criteria and procedures for the diagnosis of CIDP, and meetings were scheduled to reach a consensus on the best diagnostic workup in different clinical situations.

RESULTS

Six meetings were conducted and a consensus was reached, based on the available literature and experience in the management of such patients. Discussions resulted in defining five clinical situations in which a diagnosis of CIDP may be considered, and procedures were detailed in each case, including the location of nerve biopsy and use of non-conventional electrophysiological testing and imaging procedures.

CONCLUSION

The guidelines in the diagnostic procedure reported here result from a consensus of French experts in the field of peripheral neuropathy and allow a diagnosis of CIDP to be made in the most frequently encountered situations. These recommendations may be of value for physicians as they rely on the rational use of available techniques in typical clinical situations.

Clinical heterogeneity in mild chronic inflammatory demyelinating polyneuropathy

We describe the clinical presentation, progression and electrodiagnostic features of three patients with a mild form of chronic inflammatory demyelinating polyneuropathy (CIDP). The unusually mild but also variable clinical picture was a cause of diagnostic uncertainty in all, but CIDP was eventually confirmed by extensive electrophysiological studies in each case, as well as by histology in one. Cerebrospinal fluid protein was raised in only one patient. Two patients were treated by intravenous immunoglobulins and both improved. Awareness of the existence of this relatively benign form of CIDP in its various presentations is essential as it can be functionally disabling, progress to more severe symptomatology, and as patients may benefit from immunomodulatory therapy.

Les limites cliniques du concept de polyradiculonévrite chronique

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy is an autoimmune disease that target myelin sheats of peripheral nerves. Its diagnosis is often difficult to make, and a number of cases are probably not identified because of the clinical heterogeneity. Numerous sets of diagnostic criteria have sought to define CIDP but clinical criteria are generally not detailed.

OBJECTIVES

To review the main clinical characteristics suggestive of CIDP (that means not compatible with a length-dependent axonal process) and the critical clinical points of the neuropathy which make the differential diagnosis with the main other forms of chronic auto immune neuropathy sometimes difficult.

RESULTS

The main clinical characteristic are: a symmetric proximal and distal motor weakness predominantly affecting the lower limbs, a diffuse areflexia, a sensory deficit characterized by a preferential involvement of large fibers, an evolution which may be either chronic progressive or recurrent. These aspects raise many questions concerning overlap with other inflammatory neuropathies such as Guillain Barre syndrome, Lewis-Sumner neuropathy, chronic ataxic neuropathy. The distinction of a subgroup of CIDP associated with other diseases such as diabetes or HIV are also controversial.

CONCLUSION

The growing body of knowledge on the pathogenesis of CIDP and clinical or electrophysiological differentiation of subforms may help to develop more effective therapies for CIDP in the next few years.

Polyradiculonévrites inflammatoires démyélinisantes chroniques : stratégie diagnostique

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) comprises a group of dysimmune neuropathies easily diagnosed in more than half of the patients. Diagnosis is based on clinical, electrophysiological and biological clues. In some patients, diagnosis is unclear because of the debated value of the available clues. In such circumstances, dysimmune neuropathies may not be diagnosed, leading to insufficient treatment. This is an important category of patients because immunomodulatory drugs have proven efficacy. The CIDP spectrum includes a relatively wide range of diseases. Besides the easily recognized classic forms, there are many clinical variants, sometimes with a paucisymptomatic presentation leading to uncertain diagnosis. The French CIDP study group has established guidelines for diagnostic strategy in CIDP patients. The first part of this paper is devoted to the clinical aspects of the disease, classical forms and variants. In the second part, the results of electrophysiological studies are reported. In a third chapter, complementary examinations useful for diagnosis are discussed. The fourth chapter deals with the diagnostic strategy, discussed in relation to the different situations which may be encountered in clinical practice. details the technical modalities of appropriate electrophysiological studies and presents normal results together with those indicating demyelinating neuropathy. Nerve biopsy technique and results are given in appendix II.

Fatigue as the main presenting symptom of chronic inflammatory demyelinating polyradiculoneuropathy: a study of 11 cases

Fatigue has been shown to be more frequent than previously thought in immune-mediated polyneuropathies. However, fatigue has not been reported as the main cause of referral in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients. Between January 2001 and December 2003, we investigated 11 patients referred for fatigue, for which we established a final diagnosis of CIDP. All patients had at least two clinical examinations including assessment of the fatigue severity scale (FSS) and one electrophysiological and laboratory work up. Additionally, 10 of the 11 patients had a nerve biopsy. There were 11 male patients. Mean age at onset was 53 +/- 11 years. Main cause of referral was fatigue in all patients. Additional symptoms included cramps (one case), distal paresthesias (six cases), limb pain (seven cases) and vasomotor disturbances (one case). Cerebrospinal fluid (CSF) analysis displayed a moderate increase in protein content in four patients. Electrophysiological analysis showed abnormalities in all patients. Among 11 patients, one fulfilled the American Academy of Neurology electrodiagnostic criteria for CIDP and three fulfilled the inflammatory neuropathy cause and treatment group or the Nicolas et al. criteria. In the eight remaining patients, a nerve biopsy confirmed the diagnosis of CIDP. Ten patients were treated, among which seven showed a significant improvement based on the FSS scale. This study shows that fatigue is a possible cause of referral for patients with CIDP and, like previous reports, emphasizes the lack of sensitivity of widely accepted electrophysiological criteria of CIDP. Long-term follow up of these patients is warranted to determine the prognosis of these minimal forms of CIDP and establish the best therapeutic strategy in such cases.

Disorder resembling Guillain-Barré syndrome on initiation of statin therapy

We report a disorder resembling Guillain-Barre syndrome, occurring on initiation of simvastatin, in a 58-year-old man, who had experienced a similar but milder episode after starting pravastatin 6 months earlier. This case suggests that acute polyradiculoneuropathy may represent a rare but serious side-effect of statin treatment. It also raises the issue of the pathophysiology of acute neuropathy on statin exposure, with a hypersensitivity reaction resulting in an immune-mediated process being possible instead of the hypothesized mitochondrial dysfunction in chronic cases.

Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP): A Review of Clinical Syndromes and Treatment Approaches in Clinical Practice

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a chronic, acquired immune and inflammatory disorder of the peripheral nervous system. The classic form of the disorder is manifested by progressive or relapsing proximal or generalized limb weakness and areflexia, and usually easily recognized; it is the large number of regional and functional variants and variety of associated illnesses that pose a challenge to the clinician in practice. Similarly, laboratory and electromyography criteria have been developed to confirm the diagnosis; however, these various schemes are contrived because only 50% to 60% of patients with typical clinical features of CIDP fulfill these strict electrodiagnostic research criteria. Several studies have established the efficacy of immune therapies such as corticosteroids, plasma exchange, and intravenous immune globulin as the mainstay of treatment of CIDP, but these treatments might provide only short-term benefit. This review offers an approach to the evaluation and management of patients with CIDP and highlights the difficult clinical problems in those who do not respond or frequently relapse after treatment with standard therapies such as patients with CIDP and concomitant axonal loss, and the assessment of those with CIDP and concurrent diseases such as diabetes mellitus.

Diagnostic value of nerve biopsy for atypical chronic inflammatory demyelinating polyneuropathy: evaluation of eight cases

The diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) relies primarily on clinical and electrophysiologic examination, but the nerve biopsy findings may be supportive, especially in atypical cases. In order to define the usefulness of nerve biopsy in this disease, we retrospectively studied 44 consecutive patients whom we classified as having CIDP on pathological grounds. We found that 8 of these 44 patients had pathological findings indicative of CIDP but did not meet any of the usually accepted electrophysiological criteria for its diagnosis. Among these eight patients, five responded favorably to conventional therapy. All of these eight patients had an electrophysiological pattern of generalized axonopathy with additional subtle findings suggestive of demyelination that prompted us to perform a nerve biopsy. Our data suggest that a significant number of patients with unrecognized CIDP are erroneously classified as having chronic idiopathic axonal polyneuropathy. CIDP should be suspected if the electrophysiological examination displays subtle abnormalities suggestive of demyelination, even in the presence of a prominent axonal pattern. Nerve biopsy in these patients may reveal abnormalities suggestive of CIDP and guide therapeutic options.

Severe chronic sensory-motor polyneuropathy: coexistence of 3 unrelated etiologies in a type 1 diabetic patient. A case report and review of the literature

We present the case of a 58-year-old man, who has suffered from type 1 diabetes mellitus since he was young. He had monoclonal IgM kappa gammopathy of undetermined significance and high anti-MAG antibody titer. He developed a polyneuropathic picture with the clinical and laboratory features of chronic inflammatory demyelinating polyneuropathy within the span of approximately 2 years. He benefited from IV administration of high doses of immunoglobulins. Investigation of all parameters, but particularly of the clinical phenotype, can lead to a better definition of the polyneuropathic picture, especially for therapeutic and prognostic purposes.

Chronic inflammatory demyelinating polyneuropathy in childhood

Chronic inflammatory demyelinating polyneuropathy (CIDP) in children is relatively rare. However, it has been recognized for many years. In patients presenting with this disease, subacute onset of weakness usually develops over at least 2 months and often progresses to a loss of ambulation. Some children's initial presentations may mimic Guillain-Barré syndrome. Dysasthesias are common. Males are affected more than females, and antecedent illnesses or vaccinations occur in approximately half of patients. Physical examination reveals diffuse, proximal greater than distal weakness, with an absence or depression of muscle stretch reflexes. Electrophysiology confirms demyelination, and spinal fluid examination demonstrates albuminocytologic dissociation. The clinical presentation, diagnosis, and prognosis of childhood CIDP are reviewed. Treatment and immunologic features are also discussed in this article.

Clinical spectrum of chronic acquired demyelinating polyneuropathies

A number of presentations of chronic demyelinating polyneuropathy have been identified, each distinguished by its phenotypic pattern. In addition to classic chronic inflammatory demyelinating polyneuropathy (CIDP), which is characterized clinically by symmetric proximal and distal weakness and sensory loss, several regional variants can be recognized: multifocal motor neuropathy (MMN: asymmetric and pure motor), multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy (asymmetric, sensory, and motor), and distal acquired demyelinating symmetric (DADS) neuropathy (symmetric, distal, sensory, and motor). There are also temporal, pathological, and disease-associated variants. This review describes a clinical scheme for approaching the chronic acquired demyelinating polyneuropathies that leads to a rational use of supportive laboratory studies and treatment options. In addition, we propose new diagnostic criteria for CIDP that more accurately reflect current clinical practice.