Postural orthostatic tachycardia syndrome (POTS): Priorities for POTS care and research from a 2019 National Institutes of Health Expert Consensus Meeting - Part 2.

The National Institutes of Health hosted a workshop in 2019 to build consensus around the current state of understanding of the pathophysiology of postural orthostatic tachycardia syndrome (POTS) and to identify knowledge gaps that must be addressed to enhance clinical care of POTS patients through research. This second (of two) articles summarizes current knowledge gaps, and outlines the clinical and research priorities for POTS. POTS is a complex, multi-system, chronic disorder of the autonomic nervous system characterized by orthostatic intolerance and orthostatic tachycardia without hypotension. Patients often experience a host of other related disabling symptoms. The functional and economic impacts of this disorder are significant. The pathophysiology remains incompletely understood. Beyond the significant gaps in understanding the disorder itself, there is a paucity of evidence to guide treatment which can contribute to suboptimal care for this patient population. The vast majority of physicians have minimal to no familiarity or training in the assessment and management of POTS. Funding for POTS research remains very low relative to the size of the patient population and impact of the syndrome. In addition to efforts to improve awareness and physician education, an investment in research infrastructure including the development of standardized disease-specific evaluation tools and outcome measures is needed to facilitate effective collaborative research. A national POTS research consortium could facilitate well-controlled multidisciplinary clinical research studies and therapeutic trials. These priorities will require a substantial increase in the number of research investigators and the amount of research funding in this area.

Postural orthostatic tachycardia syndrome (POTS): State of the science and clinical care from a 2019 National Institutes of Health Expert Consensus Meeting - Part 1.

Postural orthostatic tachycardia syndrome (POTS) is a chronic and often disabling disorder characterized by orthostatic intolerance with excessive heart rate increase without hypotension during upright posture. Patients often experience a constellation of other typical symptoms including fatigue, exercise intolerance and gastrointestinal distress. A typical patient with POTS is a female of child-bearing age, who often first displays symptoms in adolescence. The onset of POTS may be precipitated by immunological stressors such as a viral infection. A variety of pathophysiologies are involved in the abnormal postural tachycardia response; however, the pathophysiology of the syndrome is incompletely understood and undoubtedly multifaceted. Clinicians and researchers focused on POTS convened at the National Institutes of Health in July 2019 to discuss the current state of understanding of the pathophysiology of POTS and to identify priorities for POTS research. This article, the first of two articles summarizing the information discussed at this meeting, summarizes the current understanding of this disorder and best practices for clinical care. The evaluation of a patient with suspected POTS should seek to establish the diagnosis, identify co-morbid conditions, and exclude conditions that could cause or mimic the syndrome. Once diagnosed, management typically begins with patient education and non-pharmacologic treatment options. Various medications are often used to address specific symptoms, but there are currently no FDA-approved medications for the treatment of POTS, and evidence for many of the medications used to treat POTS is not robust.

Intravenous Immunoglobulin Therapy in Refractory Autoimmune Dysautonomias: A Retrospective Analysis of 38 Patients.

BACKGROUND: Intravenous immunoglobulin (IVIG) has recognized efficacy in autoimmune peripheral nerve disorders, but there has been limited study of the use of IVIG in autoimmune dysautonomias. STUDY QUESTION: To determine the efficacy and safety of IVIG in patients with disabling, refractory autoimmune dysautonomias, including patients with postural tachycardia syndrome and gastrointestinal dysmotility. STUDY DESIGN: Patients with one or more autonomic disorder(s) and persistent serological evidence for autoimmunity who were unable to work or attend school despite usual treatments for dysautonomia were treated with IVIG for at least 3 months at a dose of at least 1 gm/kg monthly. MEASURES AND OUTCOMES: Outcome measures included the composite autonomic symptom scale 31 survey and a functional ability score. RESULTS: There were 38 patients, 84% female and mean age of 28.4 years. Of patients, 83.5% improved on IVIG as defined by at least 20% improvement in the composite autonomic symptom scale 31 and/or functional ability score. The mean pretreatment functional ability score was 21% (mostly bedridden), which improved to a mean of 74% (nearing able to return to work/school) for responsive patients after at least 1 year of IVIG. The mean time to the first sign of response was 5.3 weeks. There were no serious adverse events. The Mayo autoimmune dysautonomia panel antibodies and traditional Sjögren antibodies were present in only 13% and 8% of patients, respectively, but antiphospholipid antibodies and novel Sjögren antibodies were present in 76% and 42% of patients, respectively. CONCLUSIONS: There is increasing evidence that IVIG is safe and effective in a subset of patients with autonomic disorders and evidence for autoimmunity. A 4-month IVIG trial should be considered in severely affected patients who are refractory to lifestyle and pharmacological therapies. Antiphospholipid antibodies and novel Sjögren antibodies are often present in these patients and correlate with a high response rate to IVIG.

How We Treat Autoimmune Small Fiber Polyneuropathy with Immunoglobulin Therapy.

Intravenous immunoglobulin therapy is FDA approved for the immune-mediated peripheral nerve disorders Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy, and multifocal motor neuropathy. Immunoglobulin therapy has been used increasingly with significant efficacy in the treatment of patients with disabling autoimmune forms of dysautonomia, which are most often small fiber (autonomic and/or sensory) polyneuropathies. It is recognized by most who treat these disorders, however, that patients with autonomic dysfunction treated with intravenous immunoglobulin therapy develop aseptic meningitis or severe lingering headache more frequently than other patient populations when this therapy is dosed in the traditional fashion. We discuss our combined 27 years of experience with the use of immunoglobulin and other immune modulatory therapy in patients with autoimmune small fiber polyneuropathy.

Chiari type I malformation: a mimicker of myasthenia gravis.

INTRODUCTION: Myasthenia gravis is an autoimmune disease, which commonly presents with extraocular muscle weakness, eyelid ptosis, bulbar dysfunction, and proximal limb weakness. We report an unusual differential diagnosis for myasthenia gravis. CASE REPORT: A 56-year-old woman presented with worsening blurry vision, double vision, eyelid droopiness, slurred speech, and fatigable limb weakness, worsening over a 6-month period. On neurological examination, she showed dysarthric speech, ptosis, and proximal limb weakness with preserved reflexes. Myasthenia gravis was considered strongly, but serological and electrodiagnostic testing did not confirm the diagnosis of myasthenia gravis. At subsequent visits, the patient developed headaches and downbeating nystagmus, and a magnetic resonance imaging of the brain showed a Chiari type I malformation. CONCLUSIONS: Chiari type I malformation is an unusual differential for sero-negative myasthenia gravis. Magnetic resonance imaging of the brain, carried out in patients with all classical signs and symptoms of myasthenia gravis, helps identify this anomaly. Headaches, although a classic feature of Chiari type I malformation, need not be an early manifestation. Eyelid ptosis as a manifestation of Chiari malformation has not been reported in the literature.

Electrodiagnostic testing of nerves and muscles: when, why, and how to order.

The electrodiagnostic examination can provide essential information in cases of suspected peripheral nervous system disorders or injury. To optimize the yield of this test, one must have a basic understanding of how it works, when and how to order it, and its inherent limitations.