Randomized trial of intravenous immunoglobulin maintenance treatment regimens in chronic inflammatory demyelinating polyradiculoneuropathy.

BACKGROUND AND PURPOSE: High peak serum immunoglobulin G (IgG) levels may not be needed for maintenance intravenous immunoglobulin (IVIg) treatment in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and such high levels may cause side effects. More frequent lower dosing may lead to more stable IgG levels and higher trough levels, which might improve efficacy. The aim of this trial is to investigate whether high frequent low dosage IVIg treatment is more effective than low frequent high dosage IVIg treatment. METHODS: In this randomized placebo-controlled crossover trial, we included patients with CIDP proven to be IVIg-dependent and receiving an individually established stable dose and interval of IVIg maintenance treatment. In the control arm, patients received their individual IVIg dose and interval followed by a placebo infusion at half the interval. In the intervention arm, patients received half their individual dose at half the interval. After a wash-out phase patients crossed over. The primary outcome measure was handgrip strength (assessed using a Martin Vigorimeter). Secondary outcome indicators were health-related quality of life (36-item Short-Form Health Survey), disability (Inflammatory Rasch-built Overall Disability Scale), fatigue (Rasch-built Fatigue Severity Scale) and side effects. RESULTS: Twenty-five patients were included and were treated at baseline with individually adjusted dosages of IVIg ranging from 20 to 80 g and intervals ranging from 14 to 35 days. Three participants did not complete the trial; the main analysis was therefore based on the 22 patients completing both treatment periods. There was no significant difference in handgrip strength change from baseline between the two treatment regimens (coefficient -2.71, 95% CI -5.4, 0.01). Furthermore, there were no significant differences in any of the secondary outcomes or side effects. CONCLUSIONS: More frequent lower dosing does not further improve the efficacy of IVIg in stable IVIg-dependent CIDP and does not result in fewer side effects.

[Unexpected symptoms of monoclonal gammopathy]. / Onverwachte gevolgen van monoklonale gammopathie.

Monoclonal gammopathy of undetermined significance (MGUS) is a common haematological disorder characterized by the presence of a monoclonal protein (M-protein). MGUS is considered an asymptomatic 'innocent' pre-malignant precursor condition of - mostly - multiple myeloma, without indication for treatment. We present three cases illustrating that MGUS can lead to serious problems. The first patient, a 51-year-old female, presented with polyneuropathy due to anti-MAG antibodies related to IgM MGUS. The second patient, a 37-year-old female, presented with proteinuria due to immunotactoid glomerulopathy caused by renal monoclonal IgG deposition associated with MGUS. The third patient, a 55-year-old female, presented with severe bleeding caused by an aspecific inhibitor of the coagulation cascade as part of IgG MGUS. In conclusion, in addition to the risk of progression to an overt haematological malignancy, MGUS can lead to severe symptoms and significant organ damage by auto-antibody activity or pathological accumulation in tissues of its toxic M-protein.

Effect of stem cell transplantation for B-cell malignancies on disease course of associated polyneuropathy.

B cell dyscrasias are often refractory to medical treatments, and hematological stem cell therapy (SCT) may be warranted. It is not clear whether an associated polyneuropathy may also profit from SCT. In exceptional cases SCT has been tried in patients with monoclonal gammopathy and progressive polyneuropathy refractory to medical treatments. In a cohort of 225 patients with monoclonal gammopathy and polyneuropathy, we selected the six patients who underwent SCT and retrospectively examined the effects of SCT on the disease course of the associated polyneuropathy. In all patients except one, the indication for SCT was hemato-oncological (multiple myeloma in 4 patients and primary AL amyloidosis in 1). The remaining patient had an IgG monoclonal gammopathy of undetermined significance and a progressive and painful polyneuropathy for which she was treated with SCT. SCT led to improvement of motor scores and autonomic symptoms in one patient; three patients experienced improvement of neuropathic pain or sensory deficits but showed further progression of weakness. One patient showed no improvement at all. One patient died within 100 days after SCT. In conclusion, SCT as a treatment of refractory hematological malignancy may occasionally have a positive effect on the associated progressive polyneuropathy, although the benefits are very limited and the treatment-related mortality is high.

Small-fibre neuropathy can be detected in patients with chronic idiopathic axonal polyneuropathy.

BACKGROUND: The main sensory presenting symptoms of chronic idiopathic axonal polyneuropathy (CIAP) are paraesthesias, numbness and burning pain in the feet. Although these symptoms indicate the involvement of small nerve fibres, clinical analysis or electrophysiological investigations have not yet been studied in detail. METHOD: Cardiovascular autonomic tests and cold and heat pain perception threshold tests were performed in 10 patients with CIAP, 10 patients with diabetes mellitus (DM) and 10 healthy volunteers. The results of the DM group were used to see whether the tests were able to detect small-fibre neuropathy in patients with diabetes and pain. RESULTS: Quantitative sensory threshold and autonomic tests showed more frequent abnormal test results in the patients compared to the healthy control group. The proportion of abnormal test results reached significance for the deep breathing tests in both patient groups and for the cold threshold and heat pain test in patients with CIAP. The spectral analysis of RR intervals showed a significant decrease in the high frequency in both patients with DM and CIAP. CONCLUSION: The results of this study demonstrated that small-fibre neuropathy can be detected in patients with CIAP.

The additional yield of combined nerve/muscle biopsy in vasculitic neuropathy.

BACKGROUND: vasculitic neuropathy can be confirmed by demonstrating vasculitis in a nerve biopsy, but it is uncertain to what extent combined (i.e. nerve/muscle) biopsy improves the yield. METHODS: a random-effects meta-analysis was performed to assess the additional yield of combined biopsy in vasculitic neuropathy. Medline, Embase, LILACS and ISI were searched from January 1980 until January 2009 for relevant articles on the yield of nerve, muscle or combined biopsy to diagnose vasculitic neuropathy. Fourteen (15%) studies were included. Methodological quality was scored using a modified Quality Assessment for Diagnostic Accuracy Studies tool. RESULTS: in patients clinically suspected of vasculitic neuropathy, the additional yield of definite vasculitis in combined biopsy was 5.1% (95% CI 1.1-9.2%; P = 0.013). In patients diagnosed with vasculitic neuropathy, the additional yield of definite vasculitis in combined biopsy was 15% (95% CI 2.1-28%; P = 0.023). CONCLUSIONS: there is a modest additional yield of definite vasculitis in combined biopsy compared to nerve biopsy alone. Because of methodological flaws in analysed studies, the findings should be validated in a prospective study.

Peripheral Nerve Society Guideline on the classification, diagnosis, investigation, and immunosuppressive therapy of non-systemic vasculitic neuropathy: executive summary.

Non-systemic vasculitic neuropathy (NSVN) is routinely considered in the differential diagnosis of progressive axonal neuropathies, especially those with asymmetric or multifocal features. Diagnostic criteria for vasculitic neuropathy, classification criteria for NSVN, and therapeutic approaches to NSVN are not standardized. The aim of this guideline was to derive recommendations on the classification, diagnosis, investigation, and treatment of NSVN based on the available evidence and, where evidence was not available, expert consensus. Experts on vasculitis, vasculitic neuropathy, and methodology systematically reviewed the literature for articles addressing diagnostic issues concerning vasculitic neuropathy and NSVN as well as treatment of NSVN and the small-to-medium vessel primary systemic vasculitides using MEDLINE, EMBASE, and the Cochrane Library. The selected articles were analyzed and classified. The group initially reached consensus on a classification of vasculitides associated with neuropathy. Non-diabetic radiculoplexus neuropathy was incorporated within NSVN. The consensus definition of pathologically definite vasculitic neuropathy required that vessel wall inflammation be accompanied by vascular damage. Diagnostic criteria for pathologically probable vasculitic neuropathy included five predictors of definite vasculitic neuropathy: vascular deposits of IgM, C3, or fibrinogen by direct immunofluorescence; hemosiderin deposits; asymmetric nerve fiber loss; prominent active axonal degeneration; and myofiber necrosis, regeneration, or infarcts in peroneus brevis muscle biopsy (Good Practice Points from class II/III evidence). A case definition of clinically probable vasculitic neuropathy in patients lacking biopsy proof incorporated clinical features typical of vasculitic neuropathy: sensory or sensory-motor involvement, asymmetric/multifocal pattern, lower-limb predominance, distal-predominance, pain, acute relapsing course, and non-demyelinating electrodiagnostic features (Good Practice Points from class II/III evidence). Proposed exclusionary criteria for NSVN--favoring the alternate diagnosis of systemic vasculitic neuropathy--were clinicopathologic evidence of other-organ involvement; anti-neutrophil cytoplasmic antibody (ANCAs); cryoglobulins; sedimentation rate ≥100 mm/h; and medical condition/drug predisposing to systemic vasculitis (Good Practice Points supported by class III evidence). Three class III studies on treatment of NSVN were identified, which were insufficient to permit a level C recommendation. Therefore, the group reviewed the literature on treatment of primary small-to-medium vessel systemic vasculitides prior to deriving Good Practice Points on treatment of NSVN. Principal treatment recommendations were: (1) corticosteroid (CS) monotherapy for at least 6 months is considered first-line; (2) combination therapy should be used for rapidly progressive NSVN and patients who progress on CS monotherapy; (3) immunosuppressive options include cyclophosphamide, azathioprine, and methotrexate; (4) cyclophosphamide is indicated for severe neuropathies, generally administered in IV pulses to reduce cumulative dose and side effects; (5) in patients achieving clinical remission with combination therapy, maintenance therapy should be continued for 18-24 months with azathioprine or methotrexate; and (6) clinical trials to address all aspects of treatment are needed.

Randomised controlled trial comparing two different intravenous immunoglobulins in chronic inflammatory demyelinating polyradiculoneuropathy.

BACKGROUND: Different preparations of intravenous immunoglobulin (IVIg) are considered to have comparable clinical efficacy but this has never been formally investigated. Some patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) report that some IVIg brands are more effective than others. A liquid IVIg preparation is more user friendly and potentially can be infused at a faster rate. OBJECTIVES: The primary objective was to compare the efficacy of two different IVIg brands in CIDP. The secondary objective was to compare their safety. METHODS: This was an investigator-initiated multi-centre randomised controlled double-blind trial. Twenty-seven patients with active but stable CIDP treated with their individual stable IVIg (Gammagard S/D) maintenance dose and interval were randomised to receive four infusions of freeze-dried 5% IVIg (Gammagard S/D) or the new liquid 10% IVIg (Kiovig). The overall disability sum score (ODSS) was used as the primary outcome scale. The equivalence margin was defined as a difference of ≤1 point in mean ΔODSS between treatment groups. Main secondary outcome scales were the MRC sum score and the Vigorimeter. RESULTS: Repeated measurements analysis of variance, adjusted for baseline ODSS, showed a clinically insignificant treatment difference of 0.004 (95% CI -0.4 to 0.4). We also found no significant differences in any of the other outcome measures. Besides a lower occurrence of cold shivers in patients randomised to Kiovig (p=0.03), no significant differences were found in the occurrence of adverse events. CONCLUSIONS: This trial demonstrated equal clinical efficacy between a freeze-dried and a liquid IVIg preparation for maintenance treatment of CIDP.

Prognosis of polyneuropathy due to IgM monoclonal gammopathy: a prospective cohort study.

BACKGROUND: The disease course of polyneuropathy associated with immunoglobulin M monoclonal gammopathy (IgM MGUSP) can be highly variable. In order to identify factors that influence long-term disease outcome, a prospective cohort study was performed of 140 patients with IgM MGUSP over a period of 23 years. METHODS: All patients with IgM MGUSP who were diagnosed in our tertiary referral center for polyneuropathy were eligible. All patients underwent nerve conduction studies and were tested for anti-MAG antibodies. The modified Rankin Scale, graded muscle strength, quantified sensory function, and laboratory testing were performed at 0, 1, 2, and 5 years and at last visit. The primary outcome measure was the risk of developing a modified Rankin Scale score of > or = 3 points. RESULTS: A total of 140 patients with IgM MGUSP fulfilled inclusion criteria (101 [72%] demyelinating, 39 [28%] axonal, 63 [44%] MAG positive). The median age at onset was 59 years (interquartile range 52-67), median disease duration at baseline was 3.2 years (interquartile range 1.9-6). Anti-MAG antibodies were associated with a lower risk of Rankin Scale score > or = 3. Demyelination and a higher age at onset were associated with a higher risk for Rankin Scale score > or = 3. Based on these 3 factors, a Web-based prognostic model was developed that directly allows clinicians to estimate the probability of developing disability (http://www.umcutrecht.nl/subsite/Prognosis-MGUS-Neuropathy). CONCLUSION: Higher age at onset and demyelination increase the risk, whereas anti-MAG antibodies decrease the risk, of developing Rankin Scale score > or = 3 in polyneuropathy associated with immunoglobulin M monoclonal gammopathy (IgM MGUSP). Our Web-based prognostic model allows determination of prognosis in IgM MGUSP.

Detection of anti-MAG antibodies in polyneuropathy associated with IgM monoclonal gammopathy.

BACKGROUND: Detection of serum antibodies to myelin-associated glycoprotein (MAG) by Western blot (WB) is a valuable assay to diagnose a distinct type of demyelinating polyneuropathy with immunoglobulin M (IgM) monoclonal gammopathy. In this study, the diagnostic accuracy of a new and more practical ELISA to detect these antibodies was validated. METHODS: Routine WBs from 2 independent laboratories and ELISA were used to detect anti-MAG IgM in serum from 207 patients with neuropathy and controls. The sensitivity and specificity of these assays were compared and related to the patient clinical and electrophysiologic characteristics. RESULTS: In ELISA, anti-MAG antibodies were found in serum from 49 (72%) of 68 patients with demyelinating polyneuropathy and IgM monoclonal gammopathy. However, in this subgroup of patients, only 30 (44%) and 37 (54%) were positive in the 2 WBs. All of the patients positive in the 2 WBs were also positive in ELISA. A high correlation was found for IgM activity in ELISA to MAG and sulfate-3-glucuronyl paragloboside (SGPG) (Spearman rho = 0.72, p < 0.0001), supporting the notion that the shared sulfated glucuronic acid moiety of MAG and SGPG is preserved. Most patients positive in anti-MAG ELISA had a slowly progressive sensory-motor demyelinating polyneuropathy, even if the WB was negative. In control groups, however, 4 WB-negative patients with a nondemyelinating monoclonal gammopathy-related polyneuropathy were positive in anti-MAG ELISA. The remaining samples were negative in ELISA. CONCLUSION: ELISA is more sensitive than Western blot to diagnose anti-myelin-associated glycoprotein related polyneuropathy, although a positive serology may be found in other forms of polyneuropathy as well.

Rituximab for polyneuropathy with IgM monoclonal gammopathy.

BACKGROUND: Polyneuropathy with IgM monoclonal gammopathy can be a disabling disorder necessitating treatment. METHODS: In a prospective open label trial, 17 patients with disabling IgM MGUS polyneuropathy were treated with rituximab, a chimeric anti-CD-20 monoclonal antibody. RESULTS: Rituximab induced an improvement of >or=1 point on the Overall Disability Sum Score in 2/17 patients, an improvement of >or=5% of the distal MRC sum score in 4/17 and the sensory sum score in 9/17 patients. Bone marrow investigations showed CD 20 B cell depletion in all patients. There were no serious adverse events. Compared with treatment with intermittent cyclophosphamide with prednisone or treatment with fludarabine, it shows a comparable response percentages but fewer side effects. The presence of anti-MAG and a disease duration shorter than 10 years may predict treatment response. CONCLUSION: Rituximab is a candidate for treatment of IgM MGUS polyneuropathy and should be further investigated in a double-blind randomised trial.

The realistic yield of lower leg SNAP amplitudes and SRAR in the routine evaluation of chronic axonal polyneuropathies.

OBJECTIVE: To assess the realistic yield of lower leg sensory nerve action potential amplitudes (SNAP) and the sural/radial nerve amplitude ratio (SRAR) in the routine evaluation of suspected distal axonal polyneuropathy. METHODS: Investigated were 721 people. In 393 referents without and 328 patients with chronic distal symmetrical polyneuropathy the SRAR, sural, superficial peroneal and dorsal sural SNAP were determined. RESULTS: The dorsal sural SNAP could not be elicited in 26 % of referents. Axonal polyneuropathy was confirmed by an abnormally low value of the sural or superficial peroneal SNAP or SRAR in 70 % of patients, and most often (68 %) by an absent sural or superficial peroneal SNAP. In 9 % of patients there was a normal sural but abnormal superficial peroneal SNAP, and 11 % had an abnormal sural but normal superficial peroneal SNAP. ROC curve analysis demonstrated equal accuracy of the sural and superficial peroneal SNAP. CONCLUSIONS: To confirm distal axonal polyneuropathy in routine clinical practice the sural and superficial peroneal SNAP had equal and complementary yield, whereas the SRAR and dorsal sural SNAP had limited additional yield.

[Progressive, ascending neurological impairment: a spinal epidural abscess that presents as Guillain-Barré syndrome]. / Progressieve, opstijgende neurologische uitval: een spinaal epiduraal abces dat zich presenteert als het syndroom van Guillain-Barré.

Over the course of 4 days, a 65-year-old man developed fever and thoracic back pain, followed by weakness and sensory changes in both legs. Physical examination revealed dyspnoea, subfebrile temperature, neck pain withoutnuchal rigidity, sensory impairment, areflexia and weakness in both legs (and arms to a lesser extent). Guillain-Barré syndrome was considered, and treatment with intravenous immunoglobulins was started. The patient nevertheless developed respiratory insufficiency, progressive leg paresis and nuchal rigidity. Spinal MRI revealed an extensive cervicothoracic epidural abscess. Surgical decompression and drainage were performed, followed by antibiotic treatment; the patient recovered and was able to walk with assistance. A spinal epidural abscess can be difficult to recognise and is potentially lethal. The diagnosis should be considered in patients with fever and back pain, especially when these coincide with symptoms of neurological impairment. The efficacy of therapy depends on timely recognition; to this end, neuroimaging with MRI is essential.

Intermittent cyclophosphamide with prednisone versus placebo for polyneuropathy with IgM monoclonal gammopathy.

BACKGROUND: The best treatment for polyneuropathy associated with IgM monoclonal gammopathy (MGUS) is unknown. Oral cyclophosphamide combined with prednisone showed limited efficacy in a previous open label pilot study. We therefore performed a double-blind, randomized, placebo-controlled study of combined oral cyclophosphamide and prednisone in IgM MGUS polyneuropathy. METHODS: Thirty-five patients with progressive IgM MGUS polyneuropathy were included. After stratification for anti-MAG antibodies patients were randomized to oral cyclophosphamide 500 mg once daily for 4 days combined with oral prednisone 60 mg once daily for 5 days (treatment) (n = 16), or placebo (n = 19), repeated every 28 days for six times. Primary outcome was improvement of the Rivermead Mobility Index (RMI). Secondary outcomes were improvement of the modified Rankin scale, Medical Research Council and sensory sum scores, levels of M protein, EMG, and Short Form-36 scale after treatment. Patients were examined at 0, 6, 12, 18, and 24 months. RESULTS: After 6 months of treatment and at later follow-up, no difference in change of the RMI between the two groups was observed. Change of the Rankin scale was similar in both groups. Other outcome parameters showed more improvement in the treatment group: the MRC sum score improved more from 6 to 24 months after treatment; the sensory sum score improved more at 6 months; the SF 36 mean health change score and physical role score improved more; and the median nerve distal conduction (abductor pollicis brevis muscle) improved more in the treatment group. The most common adverse event was nausea. CONCLUSIONS: Compared with placebo treatment, this first double-blind randomized trial with cyclophosphamide and prednisone in IgM MGUS polyneuropathy showed no beneficial effect on the functional scales, but a beneficial effect on muscle strength and sensation was observed.

Immunosuppressive treatment for non-systemic vasculitic neuropathy.

BACKGROUND: Non-systemic vasculitic neuropathy is a rare disabling disease that usually has a subacute onset of progressive or relapsing-remitting sensory or sensorimotor deficits. Asymmetry, pain and weakness are key features. The diagnosis can only be made by exclusion of other causes, the absence of systemic vasculitis or other rheumatic diseases, and the demonstration of vasculitis in a nerve or a combined nerve and muscle biopsy. There is a need for efficacious therapy to prevent disease progression and to improve prognosis. OBJECTIVES: To assess if immunosuppressive treatment in non-systemic vasculitic neuropathy reduces disability, and ameliorates neurological symptoms, and if such therapy can be given safely. SEARCH STRATEGY: The Cochrane Neuromuscular Disease Group Trials Register (March 2006), The Cochrane Library (Issue 1, 2006), MEDLINE, EMBASE, LILACS, and ISI were searched from January 1980 until April 2006. In addition, the reference lists of relevant articles, reviews and textbooks were handsearched. SELECTION CRITERIA: All randomised or quasi-randomised trials that examined the efficacy of immunosuppressive treatment for non-systemic vasculitic neuropathy at least one year after the onset of therapy were sought. Participants had to fulfill the following criteria: absence of systemic or neurological disease, exclusion of any recognised cause of the neuropathy by appropriate clinical or laboratory investigations, electrophysiological studies in agreement with axonal neuropathy, confirmation of vasculitis in a nerve or a combined nerve and muscle biopsy. The primary outcome measure was to be improvement in disability. Secondary outcome measures were to be change in the mean disability score, change in muscle strength measured with the Medical Research Council sum score, change in pain or other positive sensory symptoms, number of relapses, and adverse events. DATA COLLECTION AND ANALYSIS: Two authors independently reviewed and extracted details of all potentially relevant trials. For included studies pooled relative risks and pooled weighted standardised mean differences were to be calculated to assess treatment efficacy. MAIN RESULTS: Fifty-nine studies were identified and assessed for possible inclusion in the review, but all were excluded because of insufficient quality or lack of relevance. AUTHORS' CONCLUSIONS: No adequate randomised or quasi-randomised controlled clinical trials have been performed on which to base treatment for non-systemic vasculitic neuropathy. Randomised trials of corticosteroids and other immunosuppressive agents are needed.

The Dutch neuromuscular database CRAMP (Computer Registry of All Myopathies and Polyneuropathies): development and preliminary data.

Each of the various neuromuscular diseases is rare. Consequently, solid epidemiological data are not available and it is often difficult to find sufficient patients for studies. For this reason, the Dutch neuromuscular database, CRAMP (Computer Registry of All Myopathies and Polyneuropathies), was developed in 2004 by the Dutch Neuromuscular Research Support Centre, to store information on patient characteristics and diagnoses (based on Rowland and McLeod's classification) in a uniform and easily retrievable manner. Care was taken to preserve data confidentiality. It is envisaged that CRAMP will prove particularly useful for studies in which multicentre collaboration is needed to recruit a sufficiently large number of patients. More than 10,000 patients with neuromuscular diseases (4,837 female, 5,476 male) have been registered since 2004, half of whom (n=5059) have peripheral nerve disorders.

Neurologic and hematologic response to fludarabine treatment in IgM MGUS polyneuropathy.

We studied the efficacy of fludarabine in 16 patients with immunoglobulin M monoclonal gammopathy of unknown significance polyneuropathy in a prospective uncontrolled trial. The modified Rankin scale improved in 5/16 patients, all of whom had a demyelinating polyneuropathy. The motor conduction velocity improved by more than 10% in two or more nerves for four of five of these patients. Hematologic response in bone marrow occurred in three of five of these patients, whereas two of five already had small polyclonal B cell populations. There were no serious side effects.

Feasibility and cost efficiency of a diagnostic guideline for chronic polyneuropathy: a prospective implementation study.

BACKGROUND: Extensive investigations are often performed to reveal the cause of chronic polyneuropathy. It is not known whether a restrictive diagnostic guideline improves cost efficiency without loss of diagnostic reliability. METHODS: In a prospective multicentre study, a comparison was made between the workup in patients with chronic polyneuropathy before and after guideline implementation. RESULTS: Three hundred and ten patients were included: 173 before and 137 after guideline implementation. In all patients, the diagnosis would remain the same if the workup was limited to the investigations in the guideline. After guideline implementation, the time to reach a diagnosis decreased by two weeks. There was a reduction of 33% in the number and costs of routine laboratory investigations/patient, and a reduction of 27% in the total number of laboratory tests/patient, despite low guideline adherence. CONCLUSION: The implementation of a diagnostic guideline for chronic polyneuropathy can reduce diagnostic delay and the number and costs of investigations for each patient without loss of diagnostic reliability. Continuous evaluation strategies after guideline implementation may improve guideline adherence and cost efficiency.

[Sensory disturbances caused by multivitamin preparations]. / Gevoelsstoornissen veroorzaakt door multivitaminepreparaten.

2 patients, men aged 60 and 65 years, presented with symptoms of chronic sensory polyneuropathy. Symptoms in the first patient were bilateral numbness in the hands and leg pain and, in the second patient, painful tingling in the legs. Pyridoxine (vitamin B6) toxicity due to daily use of multivitamin supplements was diagnosed. The patients were taking 24 and 40 mg per day, respectively. Neurotoxic syndromes due to pyridoxine overdose have been described before in patients taking high-dose vitamin B. These patients mostly developed progressive sersory neuronopathy with sensory ataxia. Chronic sensory polyneuropathy has not been associated with the use of vitamin supplements, which have previously been considered harmless. Both patients recovered after discontinuation of supplement intake.

Malignant transformation in polyneuropathy associated with monoclonal gammopathy.

OBJECTIVE: To assess the frequency of hematologic malignancies at diagnosis and to determine the incidence and predictors of malignant transformation during follow-up in patients with polyneuropathy associated with monoclonal gammopathy. METHODS: Potential predictors of malignant transformation from medical history, hematologic, neurologic, and laboratory examination performed each 6 months were evaluated by univariable and multivariable Cox proportional hazard analysis. RESULTS: Of 193 patients with polyneuropathy associated with monoclonal gammopathy, 17 patients had a hematologic malignancy at diagnosis. The incidence rate of malignant transformation in 176 patients without a malignancy at diagnosis was 2.7/100 patient years. Weight loss, progression of the polyneuropathy, unexplained fever or night sweats, and M-protein level were independent predictors. CONCLUSIONS: Since hematologic malignancies occur frequently in polyneuropathy associated with monoclonal gammopathy, the authors suggest that all patients should be screened at diagnosis and subsequently during follow-up if malignant transformation is suspected.