Acquired demyelinating polyneuropathy presenting as a pure clinical sensory syndrome

The value of sensory nerve conduction studies in the diagnosis of Guillain-Barré syndrome

Electrophysiology plays a determinant role in Guillain-Barré syndrome (GBS) diagnosis, classification, and prognostication. However, traditional electrodiagnostic (EDX) criteria for GBS rely on motor nerve conduction studies (NCS) and are suboptimal early in the course of the disease or in the setting of GBS variants. Sensory nerve conduction studies, including the sural-sparing pattern and the sensory ratio are not yet included in EDX criteria despite their well-established role in GBS diagnosis. The aim of this review is to discuss the diagnostic value of sensory NCS in GBS, their role in establishing the diagnosis and predicting the outcome according to the various subtypes of the disease.

Diagnosis and management of sensory polyneuropathy

Sensory polyneuropathies, which are caused by dysfunction of peripheral sensory nerve fibers, are a heterogeneous group of disorders that range from the common diabetic neuropathy to the rare sensory neuronopathies. The presenting symptoms, acuity, time course, severity, and subsequent morbidity vary and depend on the type of fiber that is affected and the underlying cause. Damage to small thinly myelinated and unmyelinated nerve fibers results in neuropathic pain, whereas damage to large myelinated sensory afferents results in proprioceptive deficits and ataxia. The causes of these disorders are diverse and include metabolic, toxic, infectious, inflammatory, autoimmune, and genetic conditions. Idiopathic sensory polyneuropathies are common although they should be considered a diagnosis of exclusion. The diagnostic evaluation involves electrophysiologic testing including nerve conduction studies, histopathologic analysis of nerve tissue, serum studies, and sometimes autonomic testing and cerebrospinal fluid analysis. The treatment of these diseases depends on the underlying cause and may include immunotherapy, mitigation of risk factors, symptomatic treatment, and gene therapy, such as the recently developed RNA interference and antisense oligonucleotide therapies for transthyretin familial amyloid polyneuropathy. Many of these disorders have no directed treatment, in which case management remains symptomatic and supportive. More research is needed into the underlying pathophysiology of nerve damage in these polyneuropathies to guide advances in treatment.

Immunotherapy-responsive allodynia due to distal acquired demyelinating symmetric (DADS) neuropathy

INTRODUCTION

Distal acquired demyelinating symmetric (DADS) neuropathy is a distal variant of chronic inflammatory demyelinating polyradiculoneuropathy. It is characterized by chronic distal symmetric sensory or sensorimotor deficits. Sensory ataxia is a common clinical presentation. Nerve conduction studies typically show markedly prolonged distal motor latencies.

METHODS

We report 2 patients with chronic progressive generalized pain and fatigue, with normal neurological examinations except for allodynia.

RESULTS

Nerve conduction studies were typical of DADS neuropathy. Monoclonal protein studies were negative. Cerebrospinal fluid protein levels were elevated. Sural nerve biopsies revealed segmental demyelination and remyelination. One biopsy had marked endoneurial and epineurial lymphocytic infiltration. Immunomodulatory therapy alleviated the pain and fatigue and markedly improved distal motor latencies in both patients.

CONCLUSIONS

DADS neuropathy can present with pain and a normal neurological examination apart from allodynia. Nerve conduction studies are necessary for diagnosis. These patients respond to immunotherapy better than typical DADS neuropathy patients with sensory ataxia. Muscle Nerve 54: 973-977, 2016.

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

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

Chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune disorder of the peripheral nervous system. This article highlights our current understanding of the condition along with its phenotypic variants that are encountered in clinical practice. The diagnostic evaluation of CIDP includes laboratory studies to detect associated medical conditions and electrodiagnostic studies to assess for demyelination. Current treatment options include corticosteroids, plasma exchange, and intravenous immune globulin, along with alternative therapies that may be used as corticosteroid-sparing agents or for treatment-refractory cases. Approximately 85% to 90% of patients eventually improve or stabilize with treatment, and the long-term prognosis of CIDP is favorable.

Multifocal motor neuropathy, multifocal acquired demyelinating sensory and motor neuropathy, and other chronic acquired demyelinating polyneuropathy variants

Chronic acquired demyelinating neuropathies (CADP) constitute an important group of immune neuromuscular disorders affecting myelin. This article discusses CADP with emphasis on multifocal motor neuropathy, multifocal acquired demyelinating sensory and motor neuropathy, distal acquired demyelinating symmetric neuropathy, and less common variants. Although each of these entities has distinctive laboratory and electrodiagnostic features that aid in their diagnosis, clinical characteristics are of paramount importance in diagnosing specific conditions and determining the most appropriate therapies. Knowledge regarding pathogenesis, diagnosis, and management of these disorders continues to expand, resulting in improved opportunities for identification and treatment.

Sensory Guillain-Barré syndrome and related disorders: an attempt at systematization

The possibility that some patients diagnosed with an acute sensory neuropathy could actually have Guillain-Barré syndrome (GBS) has been repeatedly advanced in the literature, but the number of cases reported is small. The reports have shown different clinical presentations and electrophysiological findings and are variously named, thus generating terminological and nosological confusion. We operatively defined sensory GBS as an acute, monophasic, widespread neuropathy characterized clinically by exclusive sensory symptoms and signs that reach their nadir in a maximum of 6 weeks without related systemic disorders and other diseases or conditions. We reviewed the literature through searches of PubMed from 1980 to March 2011 and our own files. On the basis of the size of fibers involved and the possible site of primary damage, we propose tentatively classifying sensory GBS and related disorders into three subtypes: acute sensory demyelinating polyneuropathy; acute sensory large-fiber axonopathy-ganglionopathy; and acute sensory small-fiber neuropathy-ganglionopathy.

Clinical heterogeneity in mild chronic inflammatory demyelinating polyneuropathy

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

Neurologic Complications of Plasma Cell Disorders

Plasma cell disorders are associated with a wide spectrum of neurologic complications that predominantly involve the peripheral nervous system. Distinct clinical syndromes have been recognized, and antibodies to several glycoproteins of the peripheral nervous system have been identified. The main clinical, laboratory, immunologic, and pathologic features of neurologic complications that occur in patients with monoclonal gammopathies of unknown significance, multiple myeloma, plasmacytoma, plasma cell leukemia, Waldenstrom's macroglobulinemia, and immunoglobulin-related amyloidosis are summarized in this review. Knowledge of the pathogenesis in this group of disorders has increased in recent years, allowing better diagnosis and treatment.

[The diagnosis of acquired sensory neuropathies]

INTRODUCTION

Peripheral neuropathies usually include a sensory component of various causes. The diagnosis approach requires careful a clinical assessment and a precise electrophysiological exploration.

STATE OF ART

Axonal sensory polyneuropathies are classified according to the type of fibers involved (large or small fibers). While there is a large number of causes, current emphasis is placed on glucose intolerance as a source of small-fiber sensory neuropathies. Demyelinating polyneuropathies are often associated with a monoclonal IgM gammapathy with anti-MAG activity. Multiple sensory mononeuropathies are exceptional and suggest possible early-phase vasculities, sensorymotor neuropathy with conduction blocks or leprosy. Sensory neuronopathies can also suggest Sjögren's syndrome or a paraneoplastic syndrome. Finally chronic sensory polyradiculoneuritis constitute a rare subgroup clearly defined as demyelinating inflammatory neuropathy.

CONCLUSION

The diagnostic approach to sensory neuropathies requires careful nosological electroclinical classification to reduce the number of explorations performed for etiological diagnosis.

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

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

Clinical spectrum of chronic acquired demyelinating polyneuropathies

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