The neuromuscular evaluation of postural orthostatic tachycardia syndrome.

Postural orthostatic tachycardia syndrome (POTS) is a diagnosis with a wide spectrum of symptomatology and a variety of clinicopathological associations, including hereditary, autoimmune, and infectious associations. There is little consensus regarding the appropriate diagnostic approach to the condition. The aim of this work was to provide guidance on the initial diagnosis and when and how to expand diagnostic testing. We define the "typical" POTS patient as younger, female, and with a normal examination apart from joint hyperextensibility. Red flags for "atypical" POTS would be older age at onset, male, prominent syncope, review of systems suggestive of specific alternative diagnoses, examination abnormalities other than joint hyperextensibility, or disease refractory to nonpharmacological and other first-line treatments. Although a limited evaluation is appropriate in POTS with typical features, we recommend an expanded and individualized workup in atypical cases, including additional cardiac testing, autonomic testing, neuropathy workup, and/or autoimmune workup (including consideration of Guillain-Barré syndrome), depending on clinical presentation. We emphasize the importance of shared decision-making in this condition for which treatment remains primarily symptomatic regardless of etiology.

Autonomic neuropathies.

Autonomic neuropathies represent a complex group of disorders that preferentially target autonomic fibers and can be classified as either acute/subacute or chronic in onset. Acute-onset autonomic neuropathies manifest with such conditions as paraneoplastic syndromes, Guillain-Barre syndrome, Sjögren syndrome, infection, or toxins/chemotherapy. When the presentation is acute, immune-mediated, and without a secondary cause, autoimmune autonomic ganglionopathy is likely, and should be considered for immunotherapy. Of the chronic-onset forms, diabetes is the most widespread and disabling, with autonomic impairment portending increased mortality and cardiac wall remodeling risk. Acquired light chain (AL) and transthyretin (TTR) amyloidosis represent two other key etiologies, with TTR amyloidosis now amenable to newly-approved gene-modifying therapies. The COMPASS-31 questionnaire is a validated outcome measure that can be used to monitor autonomic severity and track treatment response. Symptomatic treatments targeting orthostatic hypotension, among other symptoms, should be individualized and complement disease-modifying therapy, when possible.

Young girl presenting with exercise-induced myoglobinuria.

INTRODUCTION: The sarcoglycanopathies are a heterogeneous group of autosomal recessive limb-girdle muscular dystrophies that cause varying degrees of progressive proximal muscle weakness. METHODS: We describe the case of a Caucasian girl who presented with exercise intolerance, myalgia, and dark urine. Onset of symptoms was at age 4, and she had myalgia with physical activity throughout childhood. Creatine kinase levels were as high as 18,000. RESULTS: Immunostaining of a muscle biopsy showed mildly diminished alpha sarcoglycan staining, and SGCA gene sequencing revealed n.C229T; p.Arg77Cys (R77C) and n.C850T; p.Arg284Cys (R284C), which is associated with alpha sarcoglycanopathy. CONCLUSIONS: This patient presented with exercise intolerance, myoglobinuria, and almost normal muscle strength into adolescence, which is uncommon in sarcoglycanopathies. This uncommon presentation should be kept in mind, so that early recognition and intervention may prevent future comorbidities and help preserve the quality of life. Muscle Nerve 54: 161-164, 2016.

Elsberg Syndrome with Mixed Presentation as Meningitis Retention Syndrome: A Pediatric Case Report and Comprehensive Review of the Literature.

Elsberg syndrome is a typically infectious syndrome that may cause acute or subacute bilateral lumbosacral radiculitis and sometimes lower spinal cord myelitis. Patients often present with various neurological symptoms involving the lower extremities, including numbness, weakness, and urinary disturbances such as retention. A 9-year-old girl with no significant past medical history presented with altered mental status, fever, urinary retention, and anuria and was found to have encephalomyelitis. An extensive diagnostic workup led to ruling out possible etiologies until identifying Elsberg syndrome. In this report, we describe a case of Elsberg syndrome caused by West Nile virus (WNV). To the best of our knowledge, this is the first reported case of its kind in the pediatric population. Utilizing PubMed and Web of Science databases, we reviewed the literature to describe the neurogenic control of the urinary system in correlation to a multitude of neurologic pathologies.

A Pediatric Case of Sensory Predominant Guillain-Barré Syndrome Following COVID-19 Vaccination.

Over six billion doses of Coronavirus Disease 2019 (COVID-19) vaccines have been administered worldwide. Amidst the global COVID-19 vaccination campaign, vaccine-related side effects are of ongoing concern and investigation. According to the Centers for Disease Control and Prevention (CDC) and the United States Department of Health and Human Services, three main conditions in adults have surfaced in association with receiving the COVID-19 vaccines. These include thrombosis with thrombocytopenia syndrome (TTS), a rare syndrome involving venous or arterial thrombosis and thrombocytopenia, Guillain-Barre syndrome (GBS), and myocarditis. While a number of GBS cases in adults have been published, to our knowledge, only one pediatric case of COVID-19 vaccine-related GBS has been reported. Herein we describe a case of sensory predominant GBS following the Pfizer-BioNTech COVID-19 vaccine in a 16-year-old female presenting with bilaterally ascending upper and lower extremity numbness and paresthesia.

Effect of Ezogabine on Cortical and Spinal Motor Neuron Excitability in Amyotrophic Lateral Sclerosis: A Randomized Clinical Trial.

Importance: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of the motor nervous system. Clinical studies have demonstrated cortical and spinal motor neuron hyperexcitability using transcranial magnetic stimulation and threshold tracking nerve conduction studies, respectively, although metrics of excitability have not been used as pharmacodynamic biomarkers in multi-site clinical trials. Objective: To ascertain whether ezogabine decreases cortical and spinal motor neuron excitability in ALS. Design, Setting, and Participants: This double-blind, placebo-controlled phase 2 randomized clinical trial sought consent from eligible participants from November 3, 2015, to November 9, 2017, and was conducted at 12 US sites within the Northeast ALS Consortium. Participants were randomized in equal numbers to a higher or lower dose of ezogabine or to an identical matched placebo, and they completed in-person visits at screening, baseline, week 6, and week 8 for clinical assessment and neurophysiological measurements. Interventions: Participants were randomized to receive 600 mg/d or 900 mg/d of ezogabine or a matched placebo for 10 weeks. Main Outcomes and Measures: The primary outcome was change in short-interval intracortical inhibition (SICI; SICI-1 was used in analysis to reflect stronger inhibition from an increase in amplitude) from pretreatment mean at screening and baseline to the full-dose treatment mean at weeks 6 and 8. The secondary outcomes included levels of cortical motor neuron excitability (including resting motor threshold) measured by transcranial magnetic stimulation and spinal motor neuron excitability (including strength-duration time constant) measured by threshold tracking nerve conduction studies. Results: A total of 65 participants were randomized to placebo (23), 600 mg/d of ezogabine (23), and 900 mg/d of ezogabine (19 participants); 45 were men (69.2%) and the mean (SD) age was 58.3 (8.8) years. The SICI-1 increased by 53% (mean ratio, 1.53; 95% CI, 1.12-2.09; P = .009) in the 900-mg/d ezogabine group vs placebo group. The SICI-1 did not change in the 600-mg/d ezogabine group vs placebo group (mean ratio, 1.15; 95% CI, 0.87-1.52; P = .31). The resting motor threshold increased in the 600-mg/d ezogabine group vs placebo group (mean ratio, 4.61; 95% CI, 0.21-9.01; P = .04) but not in the 900-mg/d ezogabine group vs placebo group (mean ratio, 1.95; 95% CI, -2.64 to 6.54; P = .40). Ezogabine caused a dose-dependent decrease in excitability by several other metrics, including strength-duration time constant in the 900-mg/d ezogabine group vs placebo group (mean ratio, 0.73; 95% CI, 0.60 to 0.87; P < .001). Conclusions and Relevance: Ezogabine decreased cortical and spinal motor neuron excitability in participants with ALS, suggesting that such neurophysiological metrics may be used as pharmacodynamic biomarkers in multisite clinical trials. Trial Registration: ClinicalTrials.gov Identifier: NCT02450552.

A case of encephalomyeloradiculopathy in a non-carcinomatous patient associated with P/Q type voltage gated calcium channel antibodies.

The presence of P/Q type voltage gated calcium channel (VGCC) antibodies has been strongly correlated with Lambert Eaton Syndrome (LES), present in 90% of non-immunocompromised patients with LES. However, there have been case reports which have shown its association between paraneoplastic syndrome affecting both central nervous system and the peripheral nervous system causing encephalomyelitis and sensory neuronopathy/neuropathy. We present a case of a young man, who presented with encephalomyelitis, and was further noted to have superimposed cervical polyradiculopathy associated with P/Q type VGCC antibodies.

Isolated sciatic neuropathy as an initial manifestation of a high grade B-cell lymphoma: A case report and literature review.

Sciatic nerve neuropathy due to infiltrating of a high grade B-cell lymphoma is a very rare situation and has not often been reported. We report a case with a previous history of indolent lymphoma who presented with isolated sciatic nerve neuropathy and was found to have diffuse large B cell lymphoma involving the sciatic nerve. Although the current case is not a primary sciatic nerve lymphoma given the systematic involvement shown on MRI and PET/CT scan, the case represents a neurolymphomatosis of the sciatic nerve given the direct invasion of the lymphoma cells into the sciatic nerve. Due to the rarity of this condition, we subsequently reviewed related literatures.