Pain as the presenting symptom of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)

French recommendations for the management of adult & pediatric chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare autoimmune disorder of the peripheral nervous system, primarily affecting the myelin sheath. The pathophysiology of CIDP is complex, involving both humoral and cellular immunity. The diagnosis of CIDP should be suspected in patients with symmetrical proximal and distal motor weakness and distal sensory symptoms of progressive onset, associated with decreased/abolished tendon reflexes. Treatments include intraveinous immunoglobulins, steroids and plasma exchange, with usually an induction phase followed by a maintenance therapy with progressive weaning. Treatment should be rapidly initiated to prevent axonal degeneration, which may compromise recovery. CIDP outcome is variable, ranging from mild distal paresthesiae to complete loss of ambulation. There have been several breakthroughs in the diagnosis and management of CIDP the past ten years, e.g. discovery of antibodies against the node of Ranvier, contribution of nerve ultrasound and magnetic resonance imaging to diagnosis, and demonstration of subcutaneous immunoglobulins efficiency. This led us to elaborate French recommendations for the management of adult & pediatric CIDP patients. These recommendations include diagnosis assessment, treatment, and follow-up.

High-Dose Intravenous Immunoglobulin Is Effective in Painful Diabetic Polyneuropathy Resistant to Conventional Treatments. Results of a Double-Blind, Randomized, Placebo-Controlled, Multicenter Trial

OBJECTIVES

The efficacy and safety of high-dose intravenous immunoglobulin (IVIG) in treatment-resistant diabetic painful polyneuropathy (DPN) were assessed.

DESIGN

This was a randomized, double-blind, placebo-controlled, multicenter trial (EudraCT 2010-023883-42).

SETTING

This trial was conducted at eight sites in Italy with a neurology specialist level of care.

SUBJECTS

Twenty-six diabetic patients with DPN who reported baseline severity of pain >60 units (mm) on a VAS scale at enrollment and were resistant to antidepressants and antiepileptic drugs were enrolled; 23 were randomized (11 in the IVIG arm and 12 in the placebo arm). All patients completed the study and were evaluated. All patients were Caucasian, 15 were male, and 21 had a diagnosis of type II diabetes.

METHODS

IVIG (0.4 g/kg/d) or placebo was given for five consecutive days. Pain intensity (visual analog scale, Neuropathic Pain Symptom Inventory) and quality of life (36-Item Short-Form Health Survey, Clinical/Patient Global Impression of Change questionnaires) assessments were performed at visits: baseline, start of therapy (one week later), end of therapy (five days later), and follow-up (four and eight weeks later).

RESULTS

The study achieved its prespecified primary end point of ≥50% pain reduction at four weeks after IVIG, achieved in seven of 11 patients (63.6%) in the IVIG group vs zero of 12 in the placebo group (P = 0.0013). Only two adverse events were reported during the study: one patient in the treatment arm reported a mild "dermatitis psoriasiform," whereas one patient from the placebo group reported a mild "influenza."

CONCLUSIONS

Treatment with IVIG at the dose given was efficacious and safe for patients with DPN resistant to standard therapies.

Pain in Chronic Inflammatory Demyelinating Polyradiculoneuropathy: A Systematic Review and Meta-Analysis

INTRODUCTION

Although chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) predominantly affects large myelinated fibers, many patients have pain. The aim of this paper is to systematically review the current literature regarding CIDP with a particular focus on epidemiological and clinical characteristics of painful CIDP.

METHODS

A systematic literature search was conducted on PubMed database.

RESULTS

Our search strategy identified 146 articles. Thirty-eight papers, reporting on 991 patients, met the inclusion criteria and were used for this review. The pooled estimate of the prevalence of pain at any point within the course of CIDP was 46% (95% CI 36-57%). Immune treatment of CIDP might be adequate as monotherapy for the management of pain. Treatment specific to pain currently shows effectiveness as adjuvant treatment when CIDP is treated and pain persists.

CONCLUSIONS

Pain in CIDP is an underexplored field. Future research should focus on the natural history, phenomenology, and management of pain in CIDP.

Prognostic factor of poor outcome in anti-MAG neuropathy: clinical and electrophysiological analysis of a French Cohort

BACKGROUND

Anti-MAG polyneuropathy (anti-MAG PN) is an immune-mediated peripheral sensorimotor neuropathy characterized by distal demyelination and ataxia. However, this disorder, unlike other immune-mediated neuropathies, is difficult to treat in most cases.

METHOD

We retrospectively collected all anti-MAG PN patients followed in two hospitals for a period of 12 years to determine prognostic factors, especially those that indicated a good response to the various therapeutic strategies used.

RESULTS

Forty-seven patients were included in the study; of these, 61% had a classical 'distal demyelinating pattern', 34.2% had a 'CIDP-like pattern', and the others had an 'axonal pattern'. The most commonly used treatments were intravenous immunoglobulin (IVIg) as the first-line treatment and rituximab as the second- or third-line treatment. No prognostic factor was identified for IVIg, but electrophysiological parameters at onset were better in patients with a good response to rituximab than in non-responder patients, even though mild or high disability was observed in nearly half the patients at last examination.

CONCLUSION

Even though disability seems to progress in most cases despite the treatments used, our results suggest that an early electrophysiological reduction in sensory nerves could be considered a 'red flag' for the prompt initiation of rituximab to try to delay long-term disability.

Spinal cord stimulation in the treatment of neuropathic pain in chronic inflammatory demyelinating polyneuropathy

We describe a case of a 70-year old man with sensorimotor chronic inflammatory demyelinating polyneuropathy (CIDP) with small-fibre involvement resulting in severe diffuse neuropathic pain which was refractory to immunotherapy and anti-neuropathic medication. His pain was successfully treated with implantation of a spinal cord stimulation (SCS) system comprising bilateral cervical and lumbar epidural leads. Following SCS programming, he experienced a 50% reduction in average pain severity with substantial improvement in quality of life, persisting at 18 months after surgery. SCS has been employed to treat a variety of neuropathic pain syndromes. However, this is the first report to our knowledge of SCS utilised effectively for pain in CIDP. This therapy should be considered in painful CIDP for neuropathic pain refractory to medical management, though further studies are required to evaluate its efficacy.

One-year follow-up study of neuropathic pain in chronic inflammatory demyelinating polyradiculoneuropathy

We sought to gather information about frequency and features of neuropathic pain (NeP) in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients and to investigate course of NeP during 1-year follow-up. Study included 105 patients diagnosed with CIDP. Patients with diabetes (N = 26) were excluded. NeP was diagnosed by the official guidelines and painDETECT questionnaire (PD-Q). Medical Research Council Sum Score (MRC-SS), INCAT disability and sensory scores, and Beck Depression Inventory were also measured. PD-Q showed presence of NeP in 16 (20%) of 79 CIDP patients and their mean pain was moderate (5.1 ± 3.0 of 10). Diagnostic delay in CIDP patients with NeP was prolonged compared to CIDP patients without NeP (21 ± 28 vs 9 ± 12 months, P < .05). Slowly progressive course of the disease was more frequent in patients with NeP (81% vs 52%, P < .05). Patients with NeP had worse INCAT sensory score (P < .01), INCAT disability score (P < .05), MRC-SS, as well as worse disease outcome at time of testing (P < .05). Depression was more common in patients with NeP (69% vs 17%, P < .01). During 1-year follow-up, majority of our CIDP patients had good control of NeP with gabapentinoids or amitriptyline. NeP was common in our cohort of non-diabetic CIDP patients. It was associated with worse functional disability, worse sensory deficit, and depression. Special attention should be paid to CIDP patients with NeP because they request additional symptomatic therapy that appeared efficacious in our cohort.

Immune-mediated neuropathies

Since the discovery of an acute monophasic paralysis, later coined Guillain-Barré syndrome, almost 100 years ago, and the discovery of chronic, steroid-responsive polyneuropathy 50 years ago, the spectrum of immune-mediated polyneuropathies has broadened, with various subtypes continuing to be identified, including chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN). In general, these disorders are speculated to be caused by autoimmunity to proteins located at the node of Ranvier or components of myelin of peripheral nerves, although disease-associated autoantibodies have not been identified for all disorders. Owing to the numerous subtypes of the immune-mediated neuropathies, making the right diagnosis in daily clinical practice is complicated. Moreover, treating these disorders, particularly their chronic variants, such as CIDP and MMN, poses a challenge. In general, management of these disorders includes immunotherapies, such as corticosteroids, intravenous immunoglobulin or plasma exchange. Improvements in clinical criteria and the emergence of more disease-specific immunotherapies should broaden the therapeutic options for these disabling diseases.

Mitochondrial damage and "plugging" of transport selectively in myelinated, small-diameter axons are major early events in peripheral neuroinflammation

Background

Small-diameter, myelinated axons are selectively susceptible to dysfunction in several inflammatory PNS and CNS diseases, resulting in pain and degeneration, but the mechanism is not known.

Methods

We used in vivo confocal microscopy to compare the effects of inflammation in experimental autoimmune neuritis (EAN), a model of Guillain-Barré syndrome (GBS), on mitochondrial function and transport in large- and small-diameter axons. We have compared mitochondrial function and transport in vivo in (i) healthy axons, (ii) axons affected by experimental autoimmune neuritis, and (iii) axons in which mitochondria were focally damaged by laser induced photo-toxicity.

Results

Mitochondria affected by inflammation or laser damage became depolarized, fragmented, and immobile. Importantly, the loss of functional mitochondria was accompanied by an increase in the number of mitochondria transported towards, and into, the damaged area, perhaps compensating for loss of ATP and allowing buffering of the likely excessive Ca²⁺ concentration. In large-diameter axons, healthy mitochondria were found to move into the damaged area bypassing the dysfunctional mitochondria, re-populating the damaged segment of the axon. However, in small-diameter axons, the depolarized mitochondria appeared to “plug” the axon, obstructing, sometimes completely, the incoming (mainly anterograde) transport of mitochondria. Over time (~ 2 h), the transported, functional mitochondria accumulated at the obstruction, and the distal part of the small-diameter axons became depleted of functional mitochondria.

Conclusions

The data show that neuroinflammation, in common with photo-toxic damage, induces depolarization and fragmentation of axonal mitochondria, which remain immobile at the site of damage. The damaged, immobile mitochondria can “plug” myelinated, small-diameter axons so that successful mitochondrial transport is prevented, depleting the distal axon of functioning mitochondria. Our observations may explain the selective vulnerability of small-diameter axons to dysfunction and degeneration in a number of neurodegenerative and neuroinflammatory disorders.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1094-8) contains supplementary material, which is available to authorized users.

CIDP presenting as recurrent severe back pain without weakness or sensory loss

A 71-year-old woman presented with severe back pain, limb weakness and cranial nerve dysfunction associated with high cerebrospinal fluid (CSF) protein; we diagnosed Guillain-Barré syndrome and her symptoms completely resolved after intravenous immunoglobulin. Over the next 4 years, she had three further episodes of excruciating back pain accompanied by raised CSF protein, but without weakness, sensory loss, or abnormalities in routine nerve conduction studies. Sensory evoked potentials suggested proximal demyelination and lumbosacral plexus imaging suggested inflammation. We argue that this is a relapsing proximal polyradiculoneuropathy on the spectrum of chronic inflammatory demyelinating polyradiculoneuropathy.

Fatigue, Pain, Anxiety and Depression in Guillain-Barré Syndrome and Chronic Inflammatory Demyelinating Polyradiculoneuropathy

BACKGROUND

In the clinical evaluation of patients with Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), scant attention is paid to symptoms such as fatigue, pain and anxiety/depression. We aimed at addressing seminal studies that focused on the burden of these symptoms and their impact on quality of life (QoL) in these conditions.

SUMMARY

Fatigue, pain, and anxiety/depression are increasingly being recognized in patients with GBS and CIDP, although their pathophysiological provenance remains unknown. Fatigue and pain are significant in terms of prevalence and intensity, may be a presenting symptom, and can persist for years after apparent functional recovery, suggesting residual injury. Anxiety/depression has also been examined although studies are limited. Despite their negative impact on QoL, the long-term dynamics of these symptoms in patients with GBS and particularly CIDP receiving therapy in routine clinical practice have not been systematically evaluated. Such observations formed the basis for the ongoing (GAMEDIS) studies evaluating the effect of Gamunex on fatigue and depression in patients with CIDP, of which some preliminary data are presented.

KEY MESSAGES

Strength and sensory deficits are the main areas of focus in patients with GBS and CIDP, but they do not explain the total reduction in QoL, suggesting the possible role of other complaints. A more comprehensive approach to patient care demands that factors such as pain, fatigue and anxiety/depression receive greater attention. The non-interventional GAMEDIS studies are expected to provide valuable insight into the long-term effectiveness of Gamunex in everyday practice.

Effects of active immunisation with myelin basic protein and myelin-derived altered peptide ligand on pain hypersensitivity and neuroinflammation

Neuropathic pain is a debilitating condition in multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). Specific myelin basic protein (MBP) peptides are encephalitogenic, and myelin-derived altered peptide ligands (APLs) are capable of preventing and ameliorating EAE. We investigated the effects of active immunisation with a weakly encephalitogenic epitope of MBP (MBP87-99) and its mutant APL (Cyclo-87-99[A(91),A(96)]MBP87-99) on pain hypersensitivity and neuroinflammation in Lewis rats. MBP-treated rats exhibited significant mechanical and thermal pain hypersensitivity associated with infiltration of T cells, MHC class II expression and microglia activation in the spinal cord, without developing clinical signs of paralysis. Co-immunisation with APL significantly decreased pain hypersensitivity and neuroinflammation emphasising the important role of neuroimmune crosstalk in neuropathic pain.

Cutaneous silent period recordings in demyelinating and axonal polyneuropathies

OBJECTIVE

To investigate the cutaneous silent period (CSP), a spinal inhibitory reflex mainly mediated by A-delta fibres, in demyelinating and axonal polyneuropathy (PNP) and evaluate whether CSP parameters differ between patients with and without neuropathic pain.

METHODS

Eighty-four patients with demyelinating PNP, 178 patients with axonal PNP and 265 controls underwent clinical examination, DN4 questionnaire, standard nerve conduction study, motor-root stimulation and CSP recordings from abductor digiti minimi. We calculated the afferent conduction time of CSP (a-CSP time) with the formula: CSP latency-root motor evoked potential latency.

RESULTS

In the demyelinating PNP group the a-CSP time was significantly longer; in the axonal PNP group, CSP duration was shorter than the demyelinating group (p=0.010) and controls (p=0.001). CSP parameters were not different between patients with and without neuropathic pain.

CONCLUSIONS

The abnormality of a-CSP time in the demyelinating PNP group suggests the crucial role of A-delta fibres in the mechanism of CSP; the shorter CSP duration in the axonal PNP group supports the strong influence of the number of axons on this parameter. Our study suggests that neuropathic pain could be related to pathophysiological mechanisms differing from mere A-delta fibre loss.

SIGNIFICANCE

CSP evaluation is effective in detecting A-delta fibre dysfunction in axonal as well as demyelinating PNP.

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.

Occurrence and characterization of Pain in immune-mediated neuropathies: a multicentre prospective study

BACKGROUND

pain is a common symptom of peripheral neuropathies that may severely affect patients' Quality of Life. Pain questionnaires, based on verbal descriptors, are a useful way to investigate it.

METHODS

we performed a multicentre study through validated measures to characterize pain in a sample of consecutive patients affected by immune-mediated neuropathies.

RESULTS

ninety-three patients were enrolled in 16 Italian centres. Based on the numeric rating scale, almost half of the patients complained of moderate pain and one-third of the patients severe pain. Overall, up to 50% of our patients with immune-mediated neuropathies complained of neuropathic pain. The most common neuropathic symptoms were paraesthesia/dysesthesia and superficial spontaneous pain. Surprisingly, also patients with neuropathies commonly thought to be painless (such as multifocal motor neuropathy) reported discomfort and painful symptoms.

CONCLUSIONS

pain questionnaires should be considered in the clinical evaluation of immune-mediated neuropathies, also when evaluating therapy efficacy, because they may provide clinicians with useful information on painful symptoms and patients' quality of life.

Chronic inflammatory demyelinating polyneuropathy: diagnosis and management

Over the course of 8 weeks, a 50-year-old man developed progressive bilateral leg and arm weakness, with numbness and tingling of the feet and hands. His symptoms persisted for 6 months, with impaired manual dexterity, arm weakness when brushing his teeth, tripping when walking, inability to climb stairs and gait imbalance. On examination, there is mild proximal and distal weakness of the upper and lower extremity muscles, length-dependent sensory loss of vibratory perception and joint position sense, areflexia, positive Romberg test and steppage gait with bilateral foot drop. Motor nerve conduction studies of the arms and legs show partial conduction blocks in several nerves with nonuniform slowing, and sensory responses are absent in the hands, however, normal sural responses are noted. Lumbar puncture reveals acellular cerebrospinal fluid with elevated protein. After 2 months following treatment, his strength and gait improved significantly, and his sensory symptoms resolved.

Recurrences, vaccinations and long-term symptoms in GBS and CIDP

We determined the frequency of recurrent Guillain-Barré syndrome (GBS), whether vaccinations led to recurrences of GBS or an increase of disability in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and we assessed the prevalence of pain, fatigue and the impact on quality of life after GBS and CIDP. Additionally, we assessed the presence of common auto-immune disorders. Four hundred and sixty-one members of the Dutch society of neuromuscular disorders received a questionnaire. Two hundred and forty-five GBS and seventy-six CIDP patients were included (response rate 70%). Nine patients had a confirmed recurrent GBS, and two patients had experienced both GBS and CIDP. Common auto-immune diseases were reported in 9% of GBS and 5% of CIDP patients. None of the 106 GBS patients who received a flu vaccination (range 1-37 times, total 775 vaccinations) reported a recurrence thereafter. Five out of twenty-four CIDP patients who received a flu vaccination (range 1-17 times) reported an increase in symptoms. Pain or severe fatigue was reported in about 70% of patients after the diagnosis of GBS (median 10 years) or after onset of CIDP (median 6 years), and quality of life was significantly reduced. Flu vaccinations seem relatively safe. GBS and CIDP patients often experience pain, fatigue and a reduced quality of life for many years after the diagnosis.

Cytokine and chemokine regulation of sensory neuron function

Pain normally subserves a vital role in the survival of the organism, prompting the avoidance of situations associated with tissue damage. However, the sensation of pain can become dissociated from its normal physiological role. In conditions of neuropathic pain, spontaneous or hypersensitive pain behavior occurs in the absence of the appropriate stimuli. Our incomplete understanding of the mechanisms underlying chronic pain hypersensitivity accounts for the general ineffectiveness of currently available options for the treatment of chronic pain syndromes. Despite its complex pathophysiological nature, it is clear that neuropathic pain is associated with short- and long-term changes in the excitability of sensory neurons in the dorsal root ganglia (DRG) as well as their central connections. Recent evidence suggests that the upregulated expression of inflammatory cytokines in association with tissue damage or infection triggers the observed hyperexcitability of pain sensory neurons. The actions of inflammatory cytokines synthesized by DRG neurons and associated glial cells, as well as by astrocytes and microglia in the spinal cord, can produce changes in the excitability of nociceptive sensory neurons. These changes include rapid alterations in the properties of ion channels expressed by these neurons, as well as longer-term changes resulting from new gene transcription. In this chapter we review the diverse changes produced by inflammatory cytokines in the behavior of sensory neurons in the context of chronic pain syndromes.

[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.

Chemokines and the pathophysiology of neuropathic pain

Chemokines and chemokine receptors are widely expressed by cells of the immune and nervous systems. This review focuses on our current knowledge concerning the role of chemokines in the pathophysiology of chronic pain syndromes. Injury- or disease-induced changes in the expression of diverse chemokines and their receptors have been demonstrated in the neural and nonneural elements of pain pathways. Under these circumstances, chemokines have been shown to modulate the electrical activity of neurons by multiple regulatory pathways including increases in neurotransmitter release through Ca-dependent mechanisms and transactivation of transient receptor channels. Either of these mechanisms alone, or in combination, may contribute to sustained excitability of primary afferent and secondary neurons within spinal pain pathways. Another manner in which chemokines may influence sustained neuronal excitability may be their ability to function as excitatory neurotransmitters within the peripheral and central nervous system. As is the case for traditional neurotransmitters, injury-induced up-regulated chemokines are found within synaptic vesicles. Chemokines released after depolarization of the cell membrane can then act on other chemokine receptor-bearing neurons, glia, or immune cells. Because up-regulation of chemokines and their receptors may be one of the mechanisms that directly or indirectly contribute to the development and maintenance of chronic pain, these molecules may then represent novel targets for therapeutic intervention in chronic pain states.