Treatment for IgG and IgA paraproteinaemic neuropathy

BACKGROUND

Paraproteinaemic neuropathy refers to those neuropathies associated with a monoclonal gammopathy or paraprotein. Typically it presents with a chronic predominantly sensory, symmetrical neuropathy, similar to chronic inflammatory demyelinating polyradiculoneuropathy but with relatively more sensory involvement, both clinically and neurophysiologically. The optimal treatment for IgG and IgA monoclonal gammopathy of uncertain significance neuropathies is not known.

OBJECTIVES

The objective of this review is to examine the efficacy of any treatment for IgG or IgA paraproteinaemic peripheral neuropathy.

SEARCH STRATEGY

We performed searches of the Cochrane Neuromuscular Disease Group Trials register (May 2005), MEDLINE (from January 1966 to May 2005), EMBASE (from January 1980 to May 2005). We also checked bibliographies for controlled trials of treatments for IgG or IgA paraproteinaemic peripheral neuropathy.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials using any treatment for IgG or IgA paraproteinaemic peripheral neuropathy. People with IgM paraproteins were excluded. We excluded participants where the monoclonal gammopathy was considered secondary to an underlying disorder. We included participants of any age with a diagnosis of monoclonal gammopathy of uncertain significance with a paraprotein of the IgG or IgA class and a neuropathy. Included participants were not required to fulfil specific electrophysiological diagnostic criteria.

DATA COLLECTION AND ANALYSIS

The full texts of potentially relevant studies were obtained and assessed and independent data extraction was performed by three authors. Additional data and clarification were received from one author.

MAIN RESULTS

We identified only one randomised controlled trial with 18 participants which fulfilled the predetermined inclusion criteria. Four other trials were identified but these were not randomised controlled trials. The included trial revealed a modest short-term benefit of plasma exchange in IgG or IgA paraproteinaemic neuropathy, over a short follow-up period, when compared to sham plasma exchange.

AUTHORS' CONCLUSIONS

The evidence from randomised controlled trials for the treatment of IgG or IgA paraproteinaemic neuropathy is currently inadequate. More randomised controlled trials of treatments are required. These should have adequate follow-up periods and contain larger numbers of participants, perhaps through multicentre collaboration, considering the relative infrequency of this condition. Observational or open trial data provide limited support for the use of treatments such as plasma exchange, cyclophosphamide combined with prednisolone, intravenous immunoglobulin and corticosteroids. These show potential therapeutic promise but the potential benefits must be weighed against adverse effects. Their optimal use and the long-term benefits need to be considered and validated with well-designed randomised controlled trials.

Detection of CSF 14-3-3 protein in Guillain-Barre syndrome

OBJECTIVE

To search for biologic markers in the Guillain-Barré syndrome (GBS), we studied CSF samples from patients with GBS and neuropathy of various etiologies for the presence of 14-3-3 protein.

METHODS

CSF samples from patients with GBS, chronic neuropathies, motor neuron disease (MND), definite sporadic Creutzfeldt-Jakob disease (sCJD), and normal control subjects were analyzed by standard immunoblot assay, using a polyclonal anti-14-3-3 antibody. CSF samples were also tested with antibodies recognizing specific isoforms of 14-3-3 proteins, either after one-dimensional or two-dimensional electrophoretic separation.

RESULTS

A positive 14-3-3 assay was observed in 29 of 38 patients with GBS and in 4 patients with MND and other neuropathies, including 2 subjects with vasculitic neuropathy (VN). In GBS, 14-3-3 protein was detected as early as 12 to 48 hours after disease onset and showed an isoform pattern different from that encountered in patients with noninflammatory neuropathies, VN, MND, and sCJD. Immunohistochemical studies performed in archival fatal GBS cases disclosed marked 14-3-3 expression by mononuclear inflammatory infiltrates and Schwann cells.

CONCLUSION

CSF 14-3-3 assay may represent a useful biologic marker in patients with Guillain-Barré syndrome.

European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of multifocal motor neuropathy

Several diagnostic criteria for multifocal motor neuropathy have been proposed in recent years and a beneficial effect of intravenous immunoglobulin (IVIg) and various other immunomodulatory drugs has been suggested in several trials and uncontrolled studies. The objectives were to prepare consensus guidelines on the definition, investigation and treatment of multifocal motor neuropathy. Disease experts and a patient representative considered references retrieved from MEDLINE and the Cochrane Library in July 2004 and prepared statements which were agreed in an iterative fashion. The Task Force agreed good practice points to define clinical and electrophysiological diagnostic criteria for multifocal motor neuropathy and investigations to be considered. The principal recommendations and good practice points were: (i) IVIg (2 g/kg given over 2-5 days) should be considered as the first line treatment (level A recommendation) when disability is sufficiently severe to warrant treatment. (ii) Corticosteroids are not recommended (good practice point). (iii) If initial treatment with IVIg is effective, repeated IVIg treatment should be considered (level C recommendation). The frequency of IVIg maintenance therapy should be guided by the individual response (good practice point). Typical treatment regimens are 1 g/kg every 2-4 weeks or 2 g/kg every 4-8 weeks (good practice point). (iv) If IVIg is not or not sufficiently effective then immunosuppressive treatment may be considered. Cyclophosphamide, ciclosporin, azathioprine, interferon beta1a, or rituximab are possible agents (good practice point). (v) Toxicity makes cyclophosphamide a less desirable option (good practice point).

European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of paraproteinaemic demyelinating neuropathies: report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society*

BACKGROUND

Paraprotein-associated neuropathies have heterogeneous clinical, neurophysiological, neuropathological and haematological features. Objectives. To prepare evidence-based and consensus guidelines on the clinical management of patients with both a demyelinating neuropathy and a paraprotein (paraproteinaemic demyelinating neuropathy, PDN).

METHODS

Search of MEDLINE and the Cochrane library, review of evidence and consensus agreement of an expert panel.

RECOMMENDATIONS

In the absence of adequate data, evidence based recommendations were not possible but the panel agreed the following good practice points: (1) Patients with PDN should be investigated for a malignant plasma cell dyscrasia. (2) The paraprotein is more likely to be causing the neuropathy if the paraprotein is immunoglobulin (Ig)M, antibodies are present in serum or on biopsy, or the clinical phenotype is chronic distal sensory neuropathy. (3) Patients with IgM PDN usually have predominantly distal and sensory impairment, with prolonged distal motor latencies, and often anti-myelin associated glycoprotein antibodies. (4) IgM PDN sometimes responds to immune therapies. Their potential benefit should be balanced against their possible side-effects and the usually slow disease progression. (5) IgG and IgA PDN may be indistinguishable from chronic inflammatory demyelinating polyradiculoneuropathy, clinically, electrophysiologically, and in response to treatment. (6) For POEMS syndrome, local irradiation or resection of an isolated plasmacytoma, or melphalan with or without corticosteroids, should be considered, with haemato-oncology advice.

Immunotherapy for IgM anti-myelin-associated glycoprotein paraprotein-associated peripheral neuropathies

BACKGROUND

Serum monoclonal anti-myelin associated glycoprotein antibodies may be pathogenic in some people with IgM paraprotein and demyelinating neuropathy. Immunotherapies aimed at reducing the level of these antibodies might be expected to be beneficial.

OBJECTIVES

To examine the efficacy of any form of immunotherapy in reducing disability and impairment resulting from IgM anti-myelin associated glycoprotein paraprotein-associated demyelinating peripheral neuropathy.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Register (March 2005), MEDLINE (January 1966 to March 2005) and EMBASE (January 1980 to March 2005) for controlled trials. We also checked bibliographies and contacted authors and experts in the field.

SELECTION CRITERIA

We included randomised or quasi-randomised controlled trials of participants of any age treated with any type of immunotherapy for anti-myelin-associated glycoprotein antibody associated demyelinating peripheral neuropathy with monoclonal gammopathy of undetermined significance of any severity. Our primary outcome measure was change in the Neuropathy Impairment Scale or Modified Rankin Scale at six months after randomisationSecondary outcome measures were: Neuropathy Impairment Scale or the Modified Rankin Score at 12 months after randomisation; ten-metre walk time, subjective clinical scores and electrophysiological parameters at six and 12 months after randomisation; IgM paraprotein levels and anti-myelin associated glycoprotein antibody titres at six months after randomisation and adverse effects of treatments.

DATA COLLECTION AND ANALYSIS

We identified eight possible trials. Of these, five randomised controlled trials were included after discussion between the authors. One author extracted and the other checked the data. No missing data could be obtained from trial authors.

MAIN RESULTS

The five eligible trials (97 participants) tested intravenous immunoglobulin, interferon-alpha or plasma exchange. Only two, of intravenous immunoglobulin, had comparable interventions and outcomes but both were short-term. There were no significant benefits of the treatments used in the outcomes predefined for this review, but not all the predefined outcomes were used in every included trial. Intravenous immunoglobulin showed benefits in terms of improvement in Modified Rankin Scale at two weeks and 10-metre walk time at four weeks. Serious adverse effects of intravenous immunoglobulin are known to occur from observational studies but none were encountered in these trials.

AUTHORS' CONCLUSIONS

There is inadequate reliable evidence from trials of immunotherapies in anti-myelin associated glycoprotein paraproteinaemic neuropathy to recommend any particular immunotherapy treatment. Intravenous immunoglobulin is relatively safe and may produce some short-term benefit. Large well-designed randomised trials of at least six to 12 months duration are required to assess existing or novel therapies.

European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of chronic inflammatory demyelinating polyradiculoneuropathy: report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society

Numerous sets of diagnostic criteria have sought to define chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and randomized trials and systematic reviews of treatment have been published. The objective is to prepare consensus guidelines on the definition, investigation and treatment of CIDP. Disease experts and a patient representative considered references retrieved from MEDLINE and Cochrane Systematic Reviews in May 2004 and prepared statements which were agreed in an iterative fashion. The Task Force agreed on good practice points to define clinical and electrophysiological diagnostic criteria for CIDP with or without concomitant diseases and investigations to be considered. The principal treatment recommendations were: (1) intravenous immunoglobulin (IVIg) or corticosteroids should be considered in sensory and motor CIDP (level B recommendation); (2) IVIg should be considered as the initial treatment in pure motor CIDP (Good Practice Point); (3) if IVIg and corticosteroids are ineffective plasma exchange (PE) should be considered (level A recommendation); (4) If the response is inadequate or the maintenance doses of the initial treatment are high, combination treatments or adding an immunosuppressant or immunomodulatory drug should be considered (Good Practice Point); (5) Symptomatic treatment and multidisciplinary management should be considered (Good Practice Point).

Circulating levels of cytokines and their modulation by intravenous immunoglobulin in multifocal motor neuropathy

We found comparable levels of tumor necrosis factor (TNF)-alpha, interferon-gamma, interleukin (IL)-2, IL-4, IL-10, and IL-12 in the sera of 22 patients with multifocal motor neuropathy (MMN), 12 with amyotrophic lateral sclerosis (ALS), 12 multiple sclerosis, seven chronic inflammatory demyelinating polyneuropathy, five myasthenia gravis, and 13 healthy controls (NS). TNF-alpha levels, however, were higher in 15 (68%) MMN patients than in any NS. In all but one MMN patient tested, TNF-alpha levels repeatedly, albeit slightly, increased after each intravenous immunoglobulin infusion in parallel with clinical improvement and decreased 3-4 weeks after therapy, while in both ALS patients tested, they decreased or remained unchanged. The possible pathogenetic relevance of serum TNF-alpha modification in MMN remains to be clarified.

Long term disability and social status change after Guillain-Barré syndrome

OBJECTIVE

Even if the majority of patients with Guillain-Barré syndrome (GBS) have a favourable functional outcome some residual motor and sensory signs and symptoms may remain. The aim of this study was to evaluate the long-term effect of GBS on daily life,working activities, hobbies and social status and the presence of residual symptoms.

PATIENTS AND METHODS

Seventy patients with GBS enrolled in a case-control study were examined. Information on signs or symptoms during the acute phase of the disease was retrieved from medical records and an ad-hoc questionnaire administered during hospitalization. Patients were interviewed by phone 3 to 5 years after disease onset about residual symptoms and changes in daily living. Disability and handicap were assessed using the Hughes, Rankin and Rotterdam 9-items scale.

RESULTS

At follow-up 45 patients (64 %) made a complete functional recovery; 19 patients (27%) had some minor limitations in daily life although they were able to perform all their activities independently while 6 (9 %) needed aid for some hours or continuously during the day. Nineteen patients (27 %) had, however, to make substantial changes in their job, hobbies or social activities. There was no significant correlation between clinical and laboratory features during the acute phase of GBS and outcome.

CONCLUSIONS

Although over 90% of our GBS patients had a more or less complete functional recovery, almost 30% of them had to make substantial changes in daily life. These findings indicate that GBS still has a significant impact on patients' life which may go beyond their residual disability or impairment. Treatment of GBS should not be only aimed at improving patients' disability but also at limiting the impact of the disease on their social life.

Immunosuppressant and immunomodulatory treatments for multifocal motor neuropathy

BACKGROUND

Multifocal motor neuropathy is a distinct clinical entity characterised by progressive, predominantly distal, asymmetrical limb weakness and minimal sensory abnormality. The diagnostic feature of this condition is the presence of multiple partial motor nerve conduction blocks. Controlled trials have demonstrated the efficacy of regular intravenous immunoglobulin infusions. Immunosuppressive agents have been used as primary, second-line or adjunctive agents for its treatment. This review was undertaken to identify and review systematically randomised controlled trials of immunosuppressive agents. The use of intravenous immunoglobulin will be the subject of a separate review.

OBJECTIVES

To provide the best available evidence from randomised controlled trials on the role of immunosuppressive agents for the treatment of multifocal motor neuropathy.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group trials register for all trials of multifocal motor neuropathy published, using 'multifocal motor neuropathy' OR 'chronic inflammatory demyelinating polyradiculoneuropathy' OR ' conduction block' OR ' motor neuropathy' AND 'immunosuppressive agents', 'immunosuppressants', 'corticosteroids', 'plasma exchange', 'azathioprine', 'cyclophosphamide', 'cyclosporin', 'ciclosporin', 'methotrexate', and 'mycophenolate', 'immunomodulatory agents', 'interferon', 'total lymphoid irradiation' or 'bone marrow transplantation' as search terms. In addition we searched MEDLINE, EMBASE for 2000 and 2001 and CINAHL, LILACS for all years. We updated the register search in February 2004 and searched MEDLINE (January 1966 to end May 2004) and EMBASE (January 1980 to end May 2004).

SELECTION CRITERIA

All randomised controlled trials and quasi-randomised clinical trials in which allocation was not random but was intended to be unbiased (e.g. alternate allocation) were to have been selected. Since no such trials were discovered, all prospective and retrospective case series were included in the 'background' or 'discussion' sections of the review.

DATA COLLECTION AND ANALYSIS

All studies on multifocal motor neuropathy or lower motor neuron weakness with conduction block and no sensory abnormality were scrutinised for data on patients treated with any form of immunosuppressive agents besides intravenous immunoglobulin. The information on the outcome of treatment was then collated and summarised.

MAIN RESULTS

We found no randomised controlled trials of any immunosuppressive agents for multifocal motor neuropathy. We summarised the results of retrospective and prospective case series in the discussion of the review.

AUTHORS' CONCLUSIONS

There are no randomised controlled trials to indicate whether immunosuppressive agents are beneficial in multifocal motor neuropathy.

Multifocal motor neuropathy: current concepts and controversies

Multifocal motor neuropathy (MMN) is now a well-defined purely motor multineuropathy characterized by the presence of multifocal partial motor conduction blocks (CB), frequent association with anti-GM1 IgM antibodies, and usually a good response to high-dose intravenous immunoglobulin (IVIg) therapy. However, several issues remain to be clarified in the diagnosis, pathogenesis, and therapy of this condition including its nosological position and its relation to other chronic dysimmune neuropathies; the degree of CB necessary for the diagnosis of MMN; the existence of an axonal form of MMN; the pathophysiological basis of CB; the pathogenetic role of antiganglioside antibodies; the mechanism of action of IVIg treatments in MMN and the most effective regimen; and the treatment to be used in unresponsive patients. These issues are addressed in this review of the main clinical, electrophysiological, immunological, and therapeutic features of this neuropathy.

IgM paraproteinaemic neuropathies

PURPOSE OF REVIEW

To conduct a critical review of recent studies on the pathogenesis and treatment of IgM paraproteinaemic neuropathies and analyse their implication for patient management.

RECENT FINDINGS

A better definition and classification of IgM monoclonal gammopathies has led to recommendations on therapeutic strategies for these patients, particularly for those with the asymptomatic form of Waldenström macroglobulinemia. Studies on the pathogenetic role of IgM paraprotein in neuropathy have led to the identification of a novel antibody reactivity against trisulfated heparin disaccharide, which was associated with painful, predominantly sensory, axonal distal neuropathy. Pathological studies on patients with axonal polyneuropathy and no antibody reactivity of the IgM paraprotein have shown that vasculitis may play an important role in this form of neuropathy, as possibly confirmed by its positive response to steroids. A number of open pilot trials have addressed the effect in IgM paraproteinaemic neuropathies of the humanized monoclonal antibody (rituximab) directed against the CD20 antigen. Even if the results of these studies are less promising than initially hoped, they provide evidence that rituximab may be effective in some patients with this neuropathy.

SUMMARY

New insights into the pathogenesis of axonal forms of IgM paraproteinaemic neuropathy have derived from the identification of novel antibody reactivity and of vasculitis. The latter finding may justify the use of steroids, otherwise ineffective in IgM paraproteinaemic neuropathy. Rituximab has opened the way to more selective and apparently safer immune therapies for this neuropathy, but its efficacy needs to be confirmed by randomized controlled trials.

Polyneuropathy in POEMS syndrome: role of angiogenic factors in the pathogenesis

In order to clarify the role of angiogenic factors in polyneuropathy of POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes) syndrome, we measured the serum concentrations of vascular endothelial growth factor (VEGF) and erythropoietin (EPO) in 11 patients and correlated these with VEGF and EPO peripheral nerve expression and the degree of endoneurial vessel involvement. We found that POEMS syndrome was associated with high levels of serum VEGF and, conversely, low levels of serum EPO. Similarly, in POEMS nerves VEGF was highly expressed in blood vessels and some non-myelin-forming Schwann cells. In contrast, the expression of VEGF receptor 2 was down-regulated compared with that in normal nerves. Both EPO and EPO receptor were localized to the nerve vasculature and were expressed to similar extents in normal and POEMS nerves. The inverse correlation between VEGF and EPO serum levels was maintained during the clinical course; however, both levels returned to normal when there was a response to therapy. High serum VEGF, low serum EPO and high peripheral nerve VEGF were all associated with more severe endoneurial vessel involvement and nerve damage. Light microscopy showed an increased thickness of the basal lamina and a narrowing of the lumina of endoneurial vessels in POEMS samples, while proliferation of endothelial cells and opening of tight junctions were observed by electron microscopy. The present data support the role of angiogenic factors as diagnostic and prognostic markers of POEMS syndrome. They also suggest that VEGF and EPO are involved in the pathogenesis of polyneuropathy. In conclusion, establishing the role of angiogenic factors in polyneuropathy may lead to a better understanding of the effects of VEGF and EPO on microangiopathy and Schwann cell function.

Pathophysiological heterogeneity of conduction blocks in multifocal motor neuropathy

The pathophysiological mechanisms responsible for conduction block in multifocal motor neuropathy (MMN) are still unclear. To clarify the physiological abnormalities at the site of the block, we tested the effects induced by polarizing direct currents on motor conduction along forearm nerves in 25 normal nerves (13 subjects), and at the site of conduction block in six nerves (five patients) with MMN. In healthy controls, whereas nerve depolarization failed to change the conditioned compound muscle action potential (CMAP), hyperpolarization elicited a significant, charge-dependent, decrease in the conditioned CMAP size. Hyperpolarization with 4 mC elicited CMAPs that were 86.76 +/- 5.22% (mean +/- SEM) of the control unconditioned response (P < 0.05). Analysis of individual MMN nerves showed that polarizing currents elicited markedly heterogeneous effects: depending on the nerve tested, depolarization or hyperpolarization in most cases significantly improved conduction along motor fibres across the conduction block. In three MMN nerves, pathophysiological abnormalities were consistent with a hyperpolarizing block, in two with a depolarizing block, and in one with a mixed block. Our observations indicate that the pathophysiological abnormalities at the site of conduction block in MMN may arise from depolarization or hyperpolarization, probably depending on the course of disease.

IVIg in idiopathic autoimmune neuropathies: analysis in the light of the latest results

High-dose intravenous immunoglobulin (IVIg) is effective in the treatment of idiopathic autoimmune neuropathies including Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating neuropathy (CIDP) and multifocal motor neuropathy (MMN), representing a useful option or, as in MMN, the gold standard for their treatment. In GBS, two randomised, controlled trials (RCT) showed that IVIg is at least as effective as plasma exchange (PE). IVIg may however be preferred due to its low number of contraindications and complications and the fact that it can be administered at any time, in any department, including patients with contraindications to PE, or in intensive care units. In CIDP, at least four RCTs have demonstrated the efficacy of IVIg in over 60% of CIDP patients, while two additional RCTs have shown a comparable effect to steroids and PE as initial treatment. As with PE, the effects of IVIg usually last a few weeks meaning that the majority of patients require periodic maintenance infusions. The lower cost and easier administration of oral steroids compared to IVIg may be partly compensated by the safer long-term profile of IVIg over steroids. In MMN, almost 80% of patients improve with IVIg, the efficacy of which has been confirmed by four RCTs, making of IVIg the first-choice therapy in MMN, for which steroids and PE are ineffective or even detrimental. Also in these patients, IVIg induces a rapid improvement that usually lasts only a few weeks and has to be maintained with periodic IVIg infusions for long periods of time, if not indefinitely.

Treatment of dysimmune neuropathies

Several therapies are currently used in dys-immune neuropathies including steroids,plasma exchange (PE), high-dose intravenous immunoglobulins(IVIg), and immuno-suppressive agents (IS). Even if there is substantial evidence that these treatments may improve the course of the neuropathy, their effectiveness is far from being complete and is sometime hampered by the occurrence of associated side effects. In Guillain-Barré syndrome (GBS),IVIg and PE are similarly effective in accelerating the recovery but there is still little evidence that they can reduce mortality or long-term disability. Recent reports on the association of intravenous methylprednisolone or interferon-beta (IFN-beta) to IVIg did not result in significant further improvement. In chronic inflammatory demyelinating polyradiculoneuropathy(CIDP) steroids, PE, and IVIG are initially similarly effective. The short-term effect of PE and IVIgand the side effects associated with the long-term use of steroids have prompted the use of several IS, interferon and,more recently, the anti-CD20 monoclonal-antibody Rituximab, but their efficacy has still to be proved in controlled studies. The recent identification of multifocal motor neuropathy(MMN) was shortly followed by the finding of an effective therapy. Almost 80% of patients respond toIVIg whose effect needs to be maintained with periodic infusions for long periods of time, and tends to decrease after several years. Also in this condition a number of immune modulating agents have been used to reduce the frequency or improve the effectiveness of IVIg,but their efficacy has not been sofar confirmed in randomized trials. Similar conclusions can be drawn for neuropathies associated with monoclonal gammopathies where only PE and IVIg have proved to be effective in controlled studies,while the promising initial results obtained with Rituximab in neuropathy associated IgM monoclonal gammopathy awaits confirmation from controlled trials.

Cerebellar degeneration and hearing loss in a patient with idiopathic myenteric ganglionitis

A 35-year-old male with an 11-year history of intestinal pseudo-obstruction associated with an idiopathic inflammatory insult of the myenteric plexus and the presence of circulating anti-Hu antibodies developed a neurological syndrome characterized by bilateral hearing loss, deteriorating balance, an unsteady gait and difficulty in estimating distances. A similar neurological syndrome has previously been described in older patients among the paraneoplasic syndromes associated with small-cell lung carcinoma and the presence of circulating anti-Hu antibodies, but never in the rare cancer-free patients with anti-Hu-associated chronic idiopathic intestinal pseudo-obstruction. The patient underwent a steroid treatment. No further episodes of functional intestinal obstruction were observed and, after an initial improvement, the neurological symptoms stabilized, leaving a permanent reduction in hearing function and an unsteady gait. The case shows that an idiopathic inflammatory insult of the myenteric plexus may precede (and perhaps lead to) central nervous system impairment in patients with anti-Hu-associated chronic idiopathic intestinal pseudo-obstruction.

How long is IVIg effective in multifocal motor neuropathy?

The authors treated 10 patients with multifocal motor neuropathy (MMN) responding to an initial course of IV immunoglobulin (IVIg) with periodic infusion for 5 to 12 years (mean 8.2 years). At last follow-up, only two patients had maintained the maximal improvement achieved during therapy while eight worsened despite increasing Ig dosage. This decline started after 3 to 7 years (mean 4.8 years) of therapy and correlated with a reduction of distal compound muscle action potential amplitudes (p < 0.019). The effectiveness of IVIg in MMN often declines after several years possibly associated with the development of axonal degeneration.