Paraproteinemic neuropathy: a practical review

Effects of oral steroid sparing immunosuppressive drugs in long term maintenance treatment of chronic inflammatory demyelinating polyradiculoneuropathy

Background and objectives

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired treatable autoimmune disorder. Due to limited availability and affordability of IV immunoglobulins and therapeutic plasma exchange in Pakistan, oral immunosuppressive drugs (ISDs) are used despite limited role in literature. The study aimed to determine the response to ISDs in CIDP patients by assessing the frequency of remission, reduction of disability using a neuropathy related disability score called Inflammatory Neuropathy Cause and Treatment score (or INCAT score), as well as reduction in steroid maintenance dose.

Methods

The retrospective observational study of six months duration (May to October, 2020) was carried out in Aga Khan University Hospital, Karachi, Pakistan. Medical record of all the patients with idiopathic CIDP taking oral ISDs in last five years was selected which included bio-data, clinical signs and symptoms, medication details, and INCAT scores. Descriptive statistics were described i.e. frequency, percentages, mean/standard deviation using Microsoft Excel v.2021.

Results

Out of thirteen patients, Azathioprine was used in nine, Mycophenolate mofetil in two and Cyclosporine in two, with remission (INCAT score improvement ≥ 1) achieved in eight, one and zero patients respectively. Duration of ISDs ranged from three to twenty-four months (average 15.8 months). Patients with monoclonal paraproteinemia and prior exposure to ISDs had a poor response to the introduction of subsequent ISDs.

Conclusion

The study describes preliminary experience of the potential role of relatively cheaper and more convenient oral ISDs (especially Azathioprine) as an alternative or sparing agent to first line agents for CIDP and sets the stage for larger scale studies and randomized controlled trials.

Unraveling the unexpected: Interference in iron assay leads to diagnosis of multiple myeloma

BACKGROUND

Iron studies are critical for diagnosing iron deficiency and hemochromatosis. We present a case exhibiting macrocytic anemia with perplexingly high plasma iron concentrations.

METHODS AND RESULTS

The initial clinical presentation with significantly elevated iron results raised concerns for hemochromatosis. However, inconsistent results in dilution studies suggested the presence of an interfering substance. Inspection of the reaction curves from the instrument revealed very high background absorption in the 800 nm channel. This, coupled with the observation of an insoluble precipitate upon mixing the acid buffer reagent with the patient's serum, as well as the patient's high total protein and low albumin levels, suggested immunoglobulin overproduction. Serum protein electrophoresis confirmed a monoclonal gammopathy with a subsequent diagnosis of multiple myeloma.

CONCLUSION

Excessive monoclonal immunoglobulins can precipitate in acidic buffers and interfere with spectrophotometric measurements in iron testing. Although challenging, investigating an interference and determining its cause can uncover underlying diseases that have yet to be diagnosed.

Peripheral Neuropathy

Peripheral neuropathy is a commonly encountered diagnosis in both neurology and primary care office settings. It is important for primary care providers to identify, characterize, and diagnose patients with neuropathy. This study aims to describe the clinical presentation, diagnostic work up, and treatment options for this entity, as well as the identification of atypical features that should prompt specialized laboratory testing, electrodiagnostic testing, and neurologic consultation.

Neuralgic Amyotrophy and Hourglass Nerve Constriction/Nerve Torsion: Two Sides of the Same Coin? A Clinical Review

Neuralgic amyotrophy, also called Parsonage-Turner syndrome, in its classic presentation is a brachial plexopathy or a multifocal neuropathy, involving mainly motor nerves of the upper limb with a monophasic course. Recently, a new radiological entity was described, the hourglass constriction, which is characterized by a very focal constriction of a nerve, or part of it, usually associated with nerve thickening proximally and distally to the constriction. Another condition, which is similar from a radiological point of view to hourglass constriction, is nerve torsion. The pathophysiology of neuralgic amyotrophy, hourglass constriction and nerve torsion is still poorly understood, and a generic role of inflammation is proposed for all these conditions. It is now widely accepted that nerve imaging is necessary in identifying hourglass constrictions/nerve torsion pre-surgically in patients with an acute mononeuropathy/plexopathy. Ultrasound and MRI are useful tools for diagnosis, and they are consistent with intraoperative findings. The prognosis is generally favorable after surgery, with a high rate of good motor recovery.

Paraproteinemic Neuropathies

OBJECTIVE

Coexistence of polyneuropathy and gammopathy is a common but potentially challenging situation in clinical practice. This article reviews the clinical, electrophysiologic, and hematologic phenotypes of the paraproteinemic neuropathies and the diagnostic and treatment strategies for each.

LATEST DEVELOPMENTS

Advances in our understanding of the underlying pathophysiology of various paraproteinemic neuropathies and their corresponding phenotypes have identified potential new therapeutic targets. Therapeutic strategies to diminish anti-myelin-associated glycoprotein (MAG) IgM antibodies have shown partial and inconsistent efficacy; however, antigen-specific immune therapy is being investigated as a novel treatment to remove the presumably pathogenic anti-MAG antibody. Advances in genetic and cell signaling studies have resulted in the approval of Bruton tyrosine kinase inhibitors for Waldenström macroglobulinemia. Monoclonal antibodies are being investigated for the treatment of light chain amyloidosis.

ESSENTIAL POINTS

Early recognition and treatment of underlying plasma cell disorders improves clinical outcomes in patients with paraproteinemic neuropathy. Despite significant progress, our knowledge regarding underlying mechanisms for paraproteinemic neuropathy is still limited. Clinicians' awareness of clinical phenotypes, electrophysiologic hallmarks, and hematologic findings of the different paraproteinemic neuropathies is crucial to promptly identify and treat patients and to avert misdiagnosis. Multidisciplinary collaboration among specialists, including neurologists and hematologists, is paramount for the optimal treatment of these patients with overlapping conditions.

Monoclonal Gammopathies of Clinical Significance: A Critical Appraisal

Monoclonal gammopathies of clinical significance (MGCSs) represent a group of diseases featuring the association of a nonmalignant B cells or plasma cells clone, the production of an M-protein, and singularly, the existence of organ damage. They present a current framework that is difficult to approach from a practical clinical perspective. Several points should be addressed in order to move further toward a better understanding. Overall, these entities are only partially included in the international classifications of diseases. Its definition and classification remain ambiguous. Remarkably, its real incidence is unknown, provided that a diagnostic biopsy is mandatory in most cases. In fact, amyloidosis AL is the final diagnosis in a large percentage of patients with renal significance. On the other hand, many of these young entities are syndromes that are based on a dynamic set of diagnostic criteria, challenging a timely diagnosis. Moreover, a specific risk score for progression is lacking. Despite the key role of the clinical laboratory in the diagnosis and prognosis of these patients, information about laboratory biomarkers is limited. Besides, the evidence accumulated for many of these entities is scarce. Hence, national and international registries are stimulated. In particular, IgM MGCS deserves special attention. Until now, therapy is far from being standardized, and it should be planned on a risk and patient-adapted basis. Finally, a comprehensive and coordinated multidisciplinary approach is needed, and specific clinical trials are encouraged.

Pragmatic guide to peripheral nerve disease and the role of clinical biomarkers

In clinical neurology practice, there are few sensitive, specific and responsive serological biomarkers reflecting pathological processes affecting the peripheral nervous system. Instead, we rely on surrogate multimodality biomarkers for diagnosis and management. Correct use and interpretation of the available tests is essential to ensure that appropriate treatments are used and adjusted in a timely fashion. The incorrect application or interpretation of biomarkers can result in misdiagnosis and delays in appropriate treatment. Here, we discuss the uses and limitations of such biomarkers and discuss possible future developments.

Chronic Inflammatory Demyelinating Polyradiculoneuropathy in Association With Concomitant Diseases: Identification and Management

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare, heterogeneous, but treatable autoimmune-mediated peripheral neuropathy characterized by demyelination. CIDP can occur independently or simultaneously with a variety of diseases such as diabetes, monoclonal gammopathy of undetermined significance (MGUS), connective tissue disease, and HIV. It is important to identify CIDP and specific peripheral neuropathies caused by these diseases; this review aims to summarize the CIDP literatures related to diabetes, MGUS, SLE, and HIV, and to be helpful for the management of such patients.

Immunoglobulin M Monoclonal Gammopathies of Clinical Significance

Immunoglobulin M monoclonal gammopathy of undetermined significance (MGUS) comprises 15-20% of all cases of MGUS. IgM MGUS is distinct from other forms of MGUS in that the typical primary progression events include Waldenstrom macroglobulinaemia and light chain amyloidosis. Owing to its large pentameric structure, IgM molecules have high intrinsic viscosity and precipitate more readily than other immunoglobulin subtypes. They are also more commonly associated with autoimmune phenomena, resulting in unique clinical manifestations. Organ damage attributable to the paraprotein, not fulfilling criteria for a lymphoid or plasma cell malignancy has recently been termed monoclonal gammopathy of clinical significance (MGCS) and encompasses an important family of disorders for which diagnostic and treatment algorithms are evolving. IgM related MGCS include unique entities such as cold haemagglutinin disease, IgM related neuropathies, renal manifestations and Schnitzler's syndrome. The diagnostic approach to, and management of these disorders differs significantly from other categories of MGCS. We describe a practical approach to the evaluation of these patients and our approach to their treatment. We will also elaborate on the key unmet needs in IgM MGCS and highlight potential areas for future research.

CIDP and hemopathies, an underestimated association

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated and treatable disease that may be associated with various systemic conditions. Our objective is to describe the clinical, electrophysiological and pathological data of a series of patients with both CIDP and hemopathy. In this retrospective study, we analyzed 21 patients with CIDP and various hemopathies (malignant or not), consecutively observed for almost five years. In this particular context (with a risk of neurological complications of the hemopathy), a nerve biopsy was taken from each patient (after written consent). All the patients fulfilled the EAN/PNS electrodiagnostic criteria (2021) of CIDP: 16 with 'CIDP' and 2 with 'possible CIDP' (no data for 3 patients). For each patient, pathological analysis of nerve biopsy was compatible with the diagnosis of CIDP, and there was no evidence for hematological complication of the peripheral nervous system. In cases of peripheral neuropathy and malignant hemopathy, the possibility that the peripheral neuropathy is CIDP should not be overlooked because CIDP is clearly accessible to appropriate therapies, with high potential for a positive clinical response. If the diagnosis of CIDP is usually suspected clinically and electrophysiologically, it should be confirmed by pathological study (nerve biopsy) in certain cases. The management of such patients benefits from the collaboration of neurologists, hematologists and oncologists.

Pain in the Cancer Survivor

Recent decades have demonstrated significant strides in cancer screening, diagnostics and therapeutics. As such there have been dramatic changes in survival following a diagnosis of cancer.

Management of Myeloma Manifestations and Complications: The Cornerstone of Supportive Care: Recommendation of the Canadian Myeloma Research Group (formerly Myeloma Canada Research Network) Consensus Guideline Consortium

Multiple myeloma (MM) is a hematological cancer associated with significant symptomatic burden. Bone disease, renal insufficiency, cytopenias, infection, and peripheral neuropathy, among other disease manifestations and complications, impair patients' quality of life. The Canadian Myeloma Research Group Consensus Guideline Consortium, formerly Myeloma Canada Research Network Consensus Guideline Consortium, proposes national consensus recommendations for the management of MM-related manifestations and complications. To address the needs of Canadian physicians and people living with MM across the country, this document focuses on the improvement and maintenance of patient care by clarifying best-practice approaches for the prevention, detection and management of disease manifestations and complications. The Canadian Myeloma Research Group Consensus Guideline Consortium will periodically review the recommendations herein and update as necessary.

Spectrum of Acute Neuropathy Associated With Covid-19: A Clinical and Electrophysiological Study of 13 Patients From a Single Center

OBJECTIVES

To analyze clinical and nerve conduction patterns in patients with acute neuropathy, preceded by or concomitantly having Covid-19 disease (Acute neuropathy associated with Covid-19 or ANAC 19).

METHODS

A retrospective analysis of clinical details, laboratory evaluation and electrophysiological parameters in patients with ANAC 19 was performed. These data were compared with non-Covid Guillain-Barre syndrome (GBS) described in literature and also with patients with acute neuropathy without Covid-19 who had presented to the center during the study period.

RESULTS

Records of 13 patients with ANAC 19 were reviewed. Most patients clinically had paraparesis, and electrophysiologically showed demyelinating neuropathy. Peroneal and sural nerves were the most frequently abnormal motor and sensory nerves, respectively. A proportion of patients showed a peroneal velocity-sparing pattern. Higher incidence of paraparesis and encephalopathy differentiated ANAC 19 from non-Covid GBS.

CONCLUSIONS

ANAC 19 had a comparable electrophysiological profile to non-Covid GBS; however, it had a distinct clinical presentation.

Diffuse Large B-Cell Lymphoma Presenting as an Unusual Paraneoplastic Neurologic Syndrome Affecting the Central and Peripheral Nervous Systems

A 68-year-old man presented with a two-week history of ascending, symmetric, sensory neuropathy concerning an acute inflammatory demyelinating polyneuropathy that briefly responded to intravenous immunoglobulin (IVIg) therapy. The initial workup was negative for acquired causes. After three months of poor response to standard therapies, he was hospitalized for severe disability, unintentional weight loss, and additional, unexplained neurologic symptoms including cerebellar ataxia, dysarthria, and muscle twitching. Positron emission tomography revealed hypermetabolism isolated to the bone marrow. Bone marrow biopsy confirmed the diagnosis of diffuse large B-cell lymphoma (DLBCL). Due to rapidly worsening performance status, plasmapheresis was initiated prior to treatment with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy. His symptoms initially improved following plasmapheresis and resolved with chemotherapy. One year following treatment, he remains in complete remission. This case describes a unique paraneoplastic neurologic syndrome involving the central and peripheral nervous system that responded well to plasmapheresis and systemic chemotherapy.

Treatment Approaches for Atypical CIDP

The variants of chronic inflammatory demyelinating polyneuropathy (CIDP) differ not just in their clinical, pathological and electrophysiological characteristics, but often in their indifferent response to conventional immunosuppressive agents which are effective in typical CIDP. High quality evidence is lacking as far as the management of these atypical variants is concerned. In this review, we summarize the treatment approaches to each of these CIDP variants based on existing data. Distal acquired demyelinating symmetric polyneuropathy (DADS) has the phenotype of a symmetric, demyelinating sensory, length-dependent polyneuropathy and is frequently associated with paraproteinemia and anti myelin associated glycoprotein (MAG) antibodies. While the management of idiopathic DADS (DADS-I) is the same as CIDP, DADS-M responds suboptimally and has a favorable response to rituximab. Multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) manifests as a chronic progressive demyelinating mononeuropathy multiplex which can evolve to a confluent pattern indistinguishable from CIDP. Evidence favors treating MADSAM with conventional immunomodulatory therapy (IMT), but this disorder responds less favorably than CIDP. Some patients present with purely sensory symptoms, known as pure sensory CIDP or chronic inflammatory sensory polyradiculoneuropathy (CISP), the latter localizing to a pre-ganglionic pathology. Both respond well to first line IMT, particularly to intravenous immunoglobulin (IVIG), but patients relapse without maintenance therapy. Pure motor CIDP resembles multifocal motor neuropathy with conduction block (MMNCB), but the previously reported worsening status after steroid treatment was not reproduced in recent studies, and IVIG remains the first-line therapy. Some focal forms of CIDP defy exact classification, but respond well to first-line IMT including IVIG. Overall, atypical CIDP responds to treatment with first-line IMT, but has a suboptimal response compared to CIDP. There is evidence for effectiveness with agents such as rituximab, especially in DADS-M, and this medication can also be used in cases refractory to conventional IMTs. Rituximab is also effective in CIDP with IgG4 antibodies which has distinct clinical features and is mostly refractory to first-line IMT.

Proximal Nerve Root Involvement in immunoglobulin M Anti-Myelin-Associated Glycoprotein Neuropathy Presenting as Cauda Equina Syndrome

Typical distal symptoms in anti-myelin-associated glycoprotein (anti-MAG) neuropathy are believed to be due to the binding of immunoglobulin M to distal nerve terminals. We describe the case of a 56-year-old man diagnosed with immunoglobulin M anti-MAG neuropathy in the setting of Waldenström macroglobulinemia, which developed acute neurological worsening presenting as cauda equina syndrome. Lumbosacral magnetic resonance imaging revealed enlarged nerve roots with diffuse heterogeneous gadolinium enhancement. Treatment with steroids resulted in substantial clinical improvement. Increased recognition of atypical presentations may lead to improved characterization of anti-MAG neuropathy as a more widespread disease.

Immunoglobulin M Paraproteinaemias

Monoclonal paraproteinaemia is an increasingly common reason for referral to haematology services. Paraproteinaemias may be associated with life-threatening haematologic malignancies but can also be an incidental finding requiring only observation. Immunoglobulin M (IgM) paraproteinaemias comprise 15–20% of monoclonal proteins but pose unique clinical challenges. IgM paraproteins are more commonly associated with lymphoplasmacytic lymphoma than multiple myeloma and can occur in a variety of other mature B-cell neoplasms. The large molecular weight of the IgM multimer leads to a spectrum of clinical manifestations more commonly seen with IgM paraproteins than others. The differential diagnosis of B-cell and plasma cell dyscrasias associated with IgM gammopathies can be challenging. Although the discovery of MYD88 L265P and other mutations has shed light on the molecular biology of IgM paraproteinaemias, clinical and histopathologic findings still play a vital role in the diagnostic process. IgM secreting clones are also associated with a number of “monoclonal gammopathy of clinical significance” entities. These disorders pose a novel challenge from both a diagnostic and therapeutic perspective. In this review we provide a clinical overview of IgM paraproteinaemias while discussing the key advances which may affect how we manage these patients in the future.

Polyneuropathie im Alter

Das periphere Nervensystem ist im Laufe des Alternsprozesses Veränderungen unterworfen. So kommt es unter anderem zu einer Abschwächung von Muskeleigenreflexen und Propriozeption. Davon abzugrenzen sind Polyneuropathien als krankhafte Veränderungen des peripheren Nervensystems. Die jährliche Inzidenz von Polyneuropathien wird auf 118/100.000 geschätzt, die Prävalenz liegt bei etwa 1 %, für ältere Populationen werden 7 % angegeben. Die Ursachen sind vielfältig und ähnlich den Ursachen von Neuropathien des jüngeren Alters: Neben metabolischen, immunvermittelten, hereditären, toxischen und infektiösen Ätiologien können Polyneuropathien Ausdruck von Systemerkrankungen sein. Entsprechend der Altersverteilung der verschiedenen Ursachen sind Neuropathien im Zusammenhang mit Diabetes, monoklonalen Gammopathien und Malignomen im Alter häufiger. Allerdings nimmt der Anteil der kryptogenen Neuropathien, also ohne eindeutige Ursache, mit dem Alter zu. Bei alten Menschen führen Polyneuropathien zu einer zusätzlichen Beeinträchtigung der Mobilität und einem erhöhten Sturzrisiko, was auch die Abklärung funktioneller Fähigkeiten erforderlich macht.

Distinctive patterns of peripheral neuropathy across the spectrum of plasma cell disorders

Many patients with plasma cell disorders suffer from peripheral neuropathy, but differential diagnosis with chronic inflammatory demyelinating polyneuropathy (CIDP) is difficult. We aimed to (1) identify factors useful for differential diagnosis between peripheral neuropathy associated with plasma cell disorders versus CIDP and (2) determine whether neuropathy presentations and severity varied across the spectrum of different plasma cell disorders. A retrospective chart review of 18 monoclonal gammopathy of unknown significance (MGUS) patients, 15 POEMS syndrome patients and 34 CIDP patients between January 2005 and December 2016 was conducted. The peripheral neuropathy associated with plasma cell disorders seemed to be more sensory oriented compared to CIDP. MGUS patients were significantly older than CIDP patients (median age 70 vs. 59, respectively, p = 0.027). POEMS syndrome patients showed significantly higher platelet count at the time of neuropathy presentation compared to CIDP (p = 0.028). Lambda type MGUS patients were associated with less severe symptoms compared to POEMS syndrome patients despite harboring lambda monoclonal gammopathy as a common denominator. Kappa type MGUS patients showed predominantly axonal type neuropathy compared to its counterpart and POEMS syndrome. Careful inspection of clinical profiles and symptoms of patients presenting with neuropathy can help to discriminate those with underlying plasma cell disorders. The phenotype of neuropathy, platelet count and age at presentation seem to be the most useful indicators.

Plasma exchange in neurological disease

Plasma exchange is a highly efficient technique to remove circulating autoantibodies and other humoral factors rapidly from the vascular compartment. It was the first effective acute treatment for peripheral disorders such as Guillain-Barré syndrome and myasthenia gravis before intravenous immunoglobulin became available. The recent recognition of rapidly progressive severe antibody-mediated central nervous system disorders, such as neuromyelitis optica spectrum disorders and anti-N-methyl-D-aspartate-receptor encephalitis, has renewed interest in using plasma exchange for their acute treatment also. In this review we explain the principles and technical aspects of plasma exchange, review its current indications, and discuss the implications for its provision in the UK.

Monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant plasma cell dyscrasia that consistently precedes multiple myeloma (MM) with a 1% risk of progression per year. Recent advances have improved understanding of the complex genetic and immunologic factors that permit progression from the aberrant plasma cell clone to MGUS and overt MM. Additional evidence supports bidirectional interaction of MGUS cells with surrounding cells in the bone marrow niche that regulates malignant transformation. However, there are no robust prognostic biomarkers. Herein we review the current body of literature on the biology of MGUS and provide a rationale for the improved identification of high-risk MGUS patients who may be appropriate for novel clinical interventions to prevent progression or eradicate premalignant clones prior to the development of overt MM.

Peripheral Demyelinating Diseases: From Biology to Translational Medicine

Demyelinating diseases represent a spectrum of disorders that impose significant burden on global economy and society. Generally, the prognosis of these diseases is poor and there is no available cure. In recent decades, research has shed some light on the biology and physiology of Schwann cells and its neuroprotective effects in the peripheral nervous system (PNS). Insults to the PNS by various infectious agents, genetic predisposition and immune-related mechanisms jeopardize Schwann cell functions and cause demyelination. To date, there are no effective and reliable biomarkers for PNS-related diseases. Here, we aim to review the following: pathogenesis of various types of peripheral demyelinating diseases such as Guillain-Barre syndrome, Chronic Inflammatory Demyelinating Polyradiculoneuropathy, Anti-Myelin Associated Glycoprotein Neuropathy, POEMS syndrome, and Charcot-Marie-Tooth disease; emerging novel biomarkers for peripheral demyelinating diseases, and Schwann cell associated markers for demyelination.

Resistant type II cryoglobulinaemic vasculitis successfully treated with bortezomib in a patient with SLE

We report an interesting case of hepatitis C virus-negative type II cryoglobulinaemic vasculitis (CV) in a patient with a background history of systemic lupus erythematosus. The type II CV became less responsive to traditional treatments over time and culminated in an intensive care unit admission with critical multiorgan failure. A detailed flow cytometric evaluation of the bone marrow proved to be helpful in treatment. It demonstrated that bortezomib was a viable alternative treatment option for the type II CV. The patient received bortezomib and has made a full and durable recovery.

Approach to Peripheral Neuropathy for the Primary Care Clinician

Peripheral neuropathy is commonly encountered in the primary care setting and is associated with significant morbidity, including neuropathic pain, falls, and disability. The clinical presentation of neuropathy is diverse, with possible symptoms including weakness, sensory abnormalities, and autonomic dysfunction. Accordingly, the primary care clinician must be comfortable using the neurologic examination-including the assessment of motor function, multiple sensory modalities, and deep tendon reflexes-to recognize and characterize neuropathy. Although the causes of peripheral neuropathy are numerous and diverse, careful review of the medical and family history coupled with limited, select laboratory testing can often efficiently lead to an etiologic diagnosis. This review offers an approach for evaluating suspected neuropathy in the primary care setting. It will describe the most common causes, suggest an evidence-based workup to aid in diagnosis, and highlight recent evidence that allows for selection of symptomatic treatment of patients with neuropathy.

Acute Autonomic Symptoms with Anti-myelin-associated Glycoprotein Neuropathy as a Presentation of Small B Cell Lymphoma: A Case Report and Literature Review

The association of symmetrical distal sensorimotor polyneuropathy with anti-myelin-associated glycoprotein antibodies (MAG) has been well established. Although autonomic symptoms are uncommon with anti-MAG antibody neuropathy (MAN). We are presenting an unusual case, who developed acute onset urinary retention, orthostatic hypotension, bradycardia and was found to have MAN. She was a 68-year-old lady, presented with progressive ascending numbness, weakness of her extremities and balance problems. On neurological examination, she had generalized muscle weakness, reduced perception to all modalities of sensation with marked impairment of vibration and position sense in the lower limbs. Reflexes were diminished throughout and Romberg sign was positive. Initial lab work including thyroid-stimulating hormone (TSH), vitamin B12, Hb1c, and routine lab reports was normal. The patient then developed acute urinary retention, severe orthostatic hypotension, and symptomatic bradycardia. Workup during this time revealed M spike on serum electrophoresis with IgM kappa on immunofixation. IgM titers were higher than normal. Initially, she was thought to have monoclonal gammopathy of undetermined significance (MGUS) related neuropathy but further workup showed very high levels of anti-MAG antibody titer. Further workup including a bone marrow biopsy revealed a small B cell lymphoma. Only a few cases have reported a small B cell lymphoma presenting with MAN-associated autonomic symptoms. She is currently being treated with rituximab with significant improvement in her neuropathic symptoms. Further case studies are needed to show whether autonomic symptoms are the feature of MAN or this atypical presentation is the paraneoplastic manifestation of the lymphoma.

Multiple Myeloma of the Central Nervous System: 13 Cases and Review of the Literature

Central nervous system involvement is a rare complication of multiple myeloma with extremely poor prognosis as it usually fails to respond to therapy. We present 13 cases diagnosed at two centers in Budapest and review the current literature. The majority of our cases presented with high-risk features initially; two had plasma cell leukemia. Repeated genetic tests showed clonal evolution in 3 cases. Treatments varied according to the era, and efficacy was poor as generally reported in the literature. Only one patient is currently alive, with 3-month follow-up, and the patient responded to daratumumab-based treatment. Recent case reports show promising effectivity of pomalidomide and marizomib.

POEMS neuropathy: optimising diagnosis and management

POEMS syndrome is a rare and disabling autoinflammatory condition characterised by a typical peripheral neuropathy and the presence of a monoclonal plasma cell disorder. The acronym 'POEMS' represents the complex and multisystem features of the disease, including polyneuropathy, organomegaly, endocrinopathy, a monoclonal plasma cell disorder and skin disease. The diagnosis of POEMS is a significant challenge because of the heterogeneity of clinical presentations and variation of POEMS features. Patients are often misdiagnosed with another cause of inflammatory neuropathy and receive one or more ineffective immunomodulatory medications, resulting in delayed diagnosis and further clinical deterioration before a diagnosis is made. University College London Hospitals sees one of the largest reported POEMS cohorts in Europe, and runs a multispecialist clinic to assist with diagnosis, treatment and ongoing support. This review draws upon our experience to present the typical features of POEMS syndrome and highlight diagnostic conundrums commonly experienced, supplemented with clinical cases. We provide an investigative guide for clinicians when considering POEMS as the diagnosis, and propose a treatment algorithm that centres on the site and degree of monoclonal cell proliferation.

Are neurological complications of monoclonal gammopathy of undetermined significance underestimated?

Objectives

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignancy preceding multiple myeloma (MM) or related disorders. Neurological symptoms caused by the monoclonal immunoglobulins or free light-chains are often associated with a high morbidity. We analyzed the prevalence of neuropathy, clinical features and the long-term outcome in 223 patients (pts.) with MGUS.

Patients and Methods

Between 1/2005 and 3/2015, 223 adult pts. with MGUS were identified in our database.

Results

In36/223 pts. (16%) a neuropathy was diagnosed (MGUS associated neuropathy, MGUS-N). 20 pts. (55%) had a distal symmetric axonal neuropathy, 10 pts. (28%) had a chronic inflammatory demyelinating polyneuropathy and 6 pts (17%) a distal acquired demyelinating symmetric polyneuropathy. In MGUS-NN (without neuropathy) and in MGUS-N, progression to smoldering MM, MM or Waldenstrom's macroglobulinemia (WM) occurred in 17% of the pts. The Immunoglobulin subtype was predominantly IgG in MGUS-NN and IgM in MGUS-N and ≥5.5% plasma cells in the bone-marrow predicted progression to MM and AL-amyloidosis in MGUS-NN and to WM in MGUS-N (p<0.05).

Conclusion

Due to the substantial prevalence of neuropathies, MGUS pts. should be monitored carefully and referred to a specialized center if neurological symptoms occur.

Diseases of the peripheral nerves

This chapter reviews the diseases of the peripheral nerves from a neuropathologic point of view, with a special focus on specific morphologic changes, and includes a summary of the histopathologic methods available for their diagnosis. As the rate of obesity and the prevalence of type 2 diabetes increase, diabetic neuropathy is the most common cause of peripheral neuropathy. Many systemic disorders with metabolic origin, like amyloidosis, hepatic failure, vitamin deficiencies, uremia, lipid metabolism disorders, and others, can also cause axonal or myelin alterations in the peripheral nervous system. The most notable causes of toxic neuropathies are chemotherapeutic agents, alcohol consumption, and exposure to heavy metals and other environmental or biologic toxins. Inflammatory neuropathies cover infectious neuropathies (Lyme disease, human immunodeficiency virus, leprosy, hepatitis) and neuropathies of autoimmune origin (sarcoidosis, Guillain-Barré syndrome/acute inflammatory demyelinating polyneuropathy, chronic inflammatory demyelinating polyneuropathy, and diverse forms of vasculitis. The increasing number of known diseases causing gene mutations in hereditary peripheral neuropathies requires precise characterization, which includes histopathology.

Multiple Myeloma Associated Chronic Inflammatory Demyelinating Polyradiculoneuropathy: The Importance of Continued Surveillance

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease presenting with weakness and numbness in a remitting or chronic progressive course. It is known to have several clinical presentations and several associated diseases. CIDP has been associated with multiple myeloma, monoclonal gammopathy of undetermined significance (MGUS), and other paraproteinemias. We present a case of refractory CIDP in which the initial workup for multiple myeloma was negative, and multiple myeloma was then diagnosed two and half years later. Treatment of the multiple myeloma led to clinical improvement. This case is instructive in that perhaps more frequent surveillance for paraproteinemia in patients with CIPD, even after a negative initial workup, could lead to a better clinical outcome.