Autoimmune Axonal Neuropathies.

Objective: This article reviews autoimmune axonal neuropathies, their characteristic clinical features, disease and antibody associations, appropriate ancillary testing, treatment, and prognosis.

Latest Developments: In 2021, the American College of Rheumatology and the Vasculitis Foundation released new summary guidelines for the treatment of antineutrophil cytoplasmic autoantibody-associated vasculitides. In addition, novel autoantibodies have been recently identified; they are often paraneoplastic and associated with axonal neuropathies.

Treatment-responsive glycogen storage myopathy in a patient with POEMS syndrome: A new monoclonal gammopathy-associated myopathy.

Background: Myopathies associated with monoclonal gammopathy are relatively uncommon and underrecognized, treatable myopathies, and include sporadic late onset nemaline myopathy, light chain amyloid myopathy, and a recently described vacuolar myopathy with monoclonal gammopathy and stiffness (VAMGS). Herein, we report a new subtype of monoclonal gammopathy-associated myopathy (MGAM) in a polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes (POEMS) patient.

Method: Case report.

Plexus MRI helps distinguish the immune-mediated neuropathies MADSAM and MMN.

Background: Among immune-mediated neuropathies, clinical-electrophysiological overlap exists between multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) and multifocal motor neuropathy (MMN). Divergent immune pathogenesis, immunotherapy response, and prognosis exist between these two disorders. MRI reports have not shown distinction of these disorders, but biopsy confirmation is lacking in earlier reports.

Immune-mediated necrotizing myopathy: Unusual presentations of a treatable disease.

Introduction/aims: Immune-mediated necrotizing myopathy (IMNM) is an immune-mediated myopathy typically presenting with progressive subacute weakness and characteristic, but nonspecific, myopathological findings. Atypical cases however can mimic other inherited or acquired myopathies, depriving patients of treatment. We describe a cohort of such patients.

Neuronal intermediate filament IgGs in CSF: Autoimmune Axonopathy Biomarkers.

Objectives: To describe CSF-defined neuronal intermediate filament (NIF) autoimmunity.

Methods: NIF-IgG CSF-positive patients (41, 0.03% of 118599 tested, 1996-2019) were included (serum was neither sensitive nor specific).

: A distal myopathy with polyglucosan bodies.

Mutations in glycogenin-1 () cause an adult-onset polyglucosan body myopathy. We report here a patient presenting with late-onset distal myopathy. We wish to highlight this rare clinical phenotype of -related myopathy and the histological clues leading to its diagnosis.

Nerve Pathology Distinguishes Focal Motor Chronic Inflammatory Demyelinating Polyradiculoneuropathy From Multifocal Motor Neuropathy.

Objectives: The objective of the study is to distinguish the mechanisms of disease for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN), which we believe to be fundamentally different. However, distinguishing the mechanisms is more difficult when the presentation of CIDP is motor-predominant, focal, or asymmetric.

Methods: We describe 3 focal, motor-predominant, representative cases that could be interpreted on clinical and/or electrophysiological grounds as either MMN or focal CIDP, and present pathological findings.

Congenital myopathies in the adult neuromuscular clinic: Diagnostic challenges and pitfalls.

Objective: To investigate the spectrum of undiagnosed congenital myopathies (CMs) in adults presenting to our neuromuscular clinic and to identify the pitfalls responsible for diagnostic delays.

Methods: We conducted a retrospective review of patients diagnosed with CM in adulthood in our neuromuscular clinic between 2008 and 2018. Patients with an established diagnosis of CM before age 18 years were excluded.

Peripheral Nerve Vasculitis: Classification and Disease Associations.

"The vasculitic neuropathies encompass a wide range of disorders characterized by ischemic injury to the vasa nervorum. Patients with vasculitic neuropathies develop progressive, painful sensory or sensorimotor deficits that are typically multifocal or asymmetric. Depending on the underlying etiology, the vasculitis may be confined to the peripheral nervous system; may be one manifestation of a primary systemic vasculitis; or one manifestation of a systemic vasculitis that is secondary to underlying connective tissue disease, drug exposure, viral infection, or paraneoplastic syndrome.

Onion-bulb patterns predict acquired or inherited demyelinating polyneuropathy.

Introduction: Onion-bulbs (OB) are concentrically layered Schwann-cell processes, surrounding nerve fibers, occurring in both inherited and acquired demyelinating polyneuropathies. We investigated whether OB patterns (generalized, mixed, or focal) correlate with acquired or inherited neuropathies.

Methods: One hundred thirty-one OB-rich nerve biopsies were graded for OB pattern and inflammation without knowledge of clinical history.

Pompe Disease Could Mimic Exam Findings of Amyloidosis: Two Rare Diagnoses Bona Fide.

A 70-year-old female presented with a three-year history of evolving macroglossia causing dysphagia and dysarthria, with proximal muscle weakness. Given the classic physical finding of macroglossia, the patient underwent extensive evaluation for amyloidosis which proved to be negative apart from a bone marrow biopsy which stained positive for transthyretin without amino acid sequence abnormality, thus giving wild-type transthyretin amyloidosis. Since the wild-type transthyretin amyloidosis could not entirely explain her clinical presentation and evaluation, further studies were conducted in a sequential manner, thus leading to a diagnosis of Pompe disease explaining her presenting signs and symptoms including her macroglossia.

Brachial Plexus Neuritis Associated With Anti-Programmed Cell Death-1 Antibodies: Report of 2 Cases.

Recently, guidelines have been outlined for management of immune-related adverse events occurring with immune checkpoint inhibitors in cancer, irrespective of affected organ systems. Increasingly, these complications have been recognized as including diverse neuromuscular presentations, such as demyelinating and axonal length-dependent peripheral neuropathies, vasculitic neuropathy, myasthenia gravis, and myopathy. We present 2 cases of brachial plexopathy developing on anti-programmed cell death-1 checkpoint inhibitor therapies (pembrolizumab, nivolumab).

History, Diagnosis, and Management of Chronic Inflammatory Demyelinating Polyradiculoneuropathy.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is probably the best recognized progressive immune-mediated peripheral neuropathy. It is characterized by a symmetrical, motor-predominant peripheral neuropathy that produces both distal and proximal weakness. Large-fiber abnormalities (weakness and ataxia) predominate, whereas small-fiber abnormalities (autonomic and pain) are less common.

Subacute demyelinating polyradiculoneuropathy complicating Epstein-Barr virus infection in GATA2 haploinsufficiency.

Introduction: Autosomal dominant haploinsufficiency of GATA2 causes monocytopenia and natural killer cell lymphopenia, resulting in predisposition to mycobacterial, fungal, and viral infections.

Methods: Herein we report on the clinical, serologic, electrophysiologic, and pathologic evaluations of a 29-year-old woman with GATA2 haploinsufficiency and active Epstein-Barr virus (EBV) infection complicated by subacute painful neuropathy.

Results: Nerve conduction and electromyography studies showed predominantly demyelinating sensorimotor polyradiculoneuropathy.

GAD65 neurological autoimmunity.

The glutamic acid decarboxylase 65-kilodalton isoform (GAD65) antibody is a biomarker of autoimmune central nervous system (CNS) disorders and, more commonly, nonneurological autoimmune diseases. Type 1 diabetes, autoimmune thyroid disease, and pernicious anemia are the most frequent GAD65 autoimmune associations. One or more of these disorders coexists in approximately 70% of patients with GAD65 neurological autoimmunity.

Neurolymphomatosis: A report of 2 cases representing opposite ends of the clinical spectrum.

Introduction: Neurolymphomatosis (NL) is a rare disorder characterized by invasion of cranial or peripheral nerves, nerve roots, or plexi, usually by aggressive subtypes of non-Hodgkin lymphoma (NHL). The most common clinical presentation is that of a painful polyneuropathy or polyradiculopathy, followed by cranial neuropathy and, less frequently, by painless polyneuropathy.

Methods: Clinical and pathologic findings are reported for 2 NL cases.

Prostate cancer with perineural spread and dural extension causing bilateral lumbosacral plexopathy: case report.

Perineural tumor spread in prostate cancer is emerging as a mechanism to explain select cases of neurological dysfunction and as a cause of morbidity and tumor recurrence. Perineural spread has been shown to extend from the prostate bed to the lumbosacral plexus and then distally to the sciatic nerve or proximally to the sacral and lumbar nerves and even intradurally. The authors present a case of a bilateral neoplastic lumbosacral plexopathy that can be explained anatomically as an extension of the same process: from one lumbosacral plexus to the contralateral one utilizing the dural sac as a bridge between the opposite sacral nerve roots.

Progressive polyradiculoneuropathy due to intraneural oxalate deposition in type 1 primary hyperoxaluria.

Introduction: A 24-year-old man with primary hyperoxaluria type 1 (PH1) presented with a rapidly progressive axonal and demyelinating sensorimotor polyradiculoneuropathy shortly after the onset of end-stage renal disease. His plasma oxalate level was markedly elevated at 107 µmol/L (normal<1.8 µmol/L).