PURPOSE:No formal diagnostic criteria exist for the neuropathic subtype of postural orthostatic tachycardia syndrome (POTS). Skin biopsy and quantitative sudomotor axon reflex testing (QSORT) are preferred methods of assessment for autonomic small fiber neuropathy (SFN). This study characterizes the utility of these testing methods at a tertiary center and identifies clinical features associated with abnormal testing.METHODS:Medical records of 2658 patients undergoing tilt table testing at a single institution between June 2018 and December 2020 were reviewed. Patients with postural orthostatic tachycardia syndrome were included for analysis of intraepidermal nerve fiber density (IENFD), sweat output, comorbidities, symptoms, measures of cardiovascular autonomic function, and serum antibody levels.RESULTS:356 patients (90% female, mean age 31 ± 10) met the diagnostic criteria for postural orthostatic tachycardia syndrome. Of 211 patients who underwent quantitative sudomotor axon reflex testing, 70 (33%) demonstrated reduced sweat output. These patients were more likely to demonstrate sympathetic impairment during the Valsalva maneuver. Of 80 patients who underwent skin biopsies, 19 (24%) demonstrated reduced intraepidermal nerve fiber density. These patients tended to be older and have reduced heart rate variability during deep breathing. Neither test was associated with specific serum antibodies, symptoms, or comorbidities, though there was a trend toward higher rates of comorbid autoimmune disease in patients with abnormal testing.CONCLUSION:A subset of patients with postural orthostatic tachycardia syndrome have evidence of small fiber neuropathy. These patients tend to have impaired cardiovascular autonomic function but are otherwise similar to patients with no evidence of small fiber neuropathy.

Background Miscommunications during care transfers are a leading cause of medical errors. Recent consensus-based recommendations to standardise information transfer from outpatient clinics to the emergency department (ED) have not been formally evaluated. We sought to determine whether a receiver-driven structured handoff intervention is associated with 1) increased inclusion of standardised elements; 2) reduced miscommunications and 3) increased perceived quality, safety and efficiency. Methods We conducted a prospective intervention study in a paediatric ED and affiliated clinics in 2016-2018. We developed a bundled handoff intervention included a standard template, receiver training, awareness campaign and iterative feedback. We assessed a random sample of audio-recorded handoffs and associated medical records to measure rates of inclusion of standardised elements and rate of miscommunications. We surveyed key stakeholders pre-intervention and post-intervention to assess perceptions of quality, safety and efficiency of the handoff process. Results Across 162 handoffs, implementation of a receiver-driven intervention was associated with significantly increased inclusion of important elements, including illness severity (46% vs 77%), tasks completed (64% vs 83%), expectations (61% vs 76%), pending tests (0% vs 64%), contingency plans (0% vs 54%), detailed callback request (7% vs 81%) and synthesis (2% vs 73%). Miscommunications decreased from 48% to 26%, a relative reduction of 23% (95% CI -39% to -7%). Perceptions of quality (35% vs 59%), safety (43% vs 73%) and efficiency (17% vs 72%) improved significantly post-intervention. Conclusions Implementation of a receiver-driven intervention to standardise clinic-to-ED handoffs was associated with improved communication quality. These findings suggest that expanded implementation of similar programmes may significantly improve the care of patients transferred to the paediatric ED.

Purpose and Hypothesis: To identify and distinguish central autonomic dysfunction from peripheral autonomic dysfunction (or both) in migraineurs suffering from orthostatic intolerance (OI) compared to migraineurs not suffering from OI. We hypothesize that OI manifests from a predominantly central autonomic component.Methods: We studied two populations of migraineurs, one group complaining of symptoms of OI for 6 months or longer and a group without OI symptoms, using a 70-degree, 45-minute passive head-up tilt-table test (HUT), R-R interval measurements during deep breathing, blood pressure and heart rate monitoring during Valsalva maneuver and release, Quantitative Sudomotor Axon Reflex Test (QSART), and skin biopsy for intraepidermal nerve fiber density. Categorical differences between the two populations were compared using exact likelihood ratio chi-square tests, and 95% confidence intervals for sensitivity, specificity, positive and negative predictive values were calculated.Results: Thirty-seven migraineurs with OI (Group 1) and 22 migraineurs without (Group 2) were studied and were demographically similar except for a greater representation of migraines with brainstem auras in Group 1 (27% v 5%; p= 0.032). Ninety-seven percent of Group 1 patients, versus 68% Group 2, manifested abnormal 45-minutes HUT, a significant difference (p=0.020, Fisher’s exact test). The first 5-minute evaluation of the HUT exhibited high specificity (1.00; 95% CI: 0.85-1.00) for the diagnosis of postural tachycardia syndrome (POTS) with a positive predictive value of 1.00 (0.59, 1.00; p=0.037). The HUT extended to 45-minutes however showed greater sensitivity compared with the 10-minute HUT (0.95; 95% CI:0.82-0.99; p=0.020). We found no differences between groups in autonomic laboratory or skin biopsy findings. Fifty-seven percent of Group 1 and 50% of Group 2 exhibited biopsy-proven small fiber neuropathy (SFN), a difference that did not reach statistical significance.Conclusions: We failed to confirm our hypothesis that OI is a manifestation of a central autonomic dysfunction in migraineurs. The finding of SFN in a majority of subjects points to peripheral autonomic contributions and raises the possibility of an underlying systemic disorder. Extending HUT table testing to 45-minutes increases diagnostic sensitivity and better reflects life events.Funding Statement: This study was supported by a grant from the Bakken Heart-Brain Institute, Cleveland Clinic, Cleveland, Ohio, USA.Declaration of Interests: We declare no competing interests.Ethics Approval Statement: The study was approved by the Cleveland Clinic’s Institutional Review Board. Informed consent was obtained from all participants in the study.

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A 36-year-old female with symptoms of orthostatic intolerance and syncope was diagnosed with vasovagal syncope on a tilt table test and with postural tachycardia syndrome (POTS) after a repeat tilt table test. However, an echocardiogram at our institution revealed obstructive cardiomyopathy without severe septal hypertrophy, with a striking increase in left ventricular outflow tract gradient from 7 mmHg at rest to 75 mmHg during Valsalva, with a septal thickness of only 1.3 cm. Cardiac MRI showed an apically displaced multiheaded posteromedial papillary muscle with suggestion of aberrant chordal attachments to the anterior mitral leaflet contributing to systolic anterior motion of the mitral valve. She underwent surgery with reorientation of the posterior medial papillary muscle head, resection of the tethering secondary chordae to the A1 segment of the mitral valve, chordal shortening and tacking of the chordae to the A1 and A2 segments of the mitral valve, and gentle septal myectomy. After surgery, she had significant improvement in her prior symptoms. To our knowledge, this is the first reported case of obstructive cardiomyopathy without severe septal hypertrophy with abnormalities in papillary muscle and chordal attachment, in a patient diagnosed with vasovagal syncope and POTS.

BACKGROUND:Miscommunication during patient transfers is a leading cause of medical errors. Inpatient standardization of handoff communication has been associated with reduced medical errors, but less is known about best practices for handoffs from referring providers to the emergency department (ED). The study aims were to identify (1) stakeholder perceptions of current handoff processes and (2) key handoff elements and strategies to optimize patient care on transfer.METHODS:A mixed-methods needs assessment study was conducted at a tertiary care children's hospital with a communication center that receives verbal handoff via telephone from referring providers and provides written summary to the ED. ED, primary care providers, and communication center staff were surveyed to understand perceptions of handoff processes and ideal handoff elements. Focus groups were conducted to refine concepts. Descriptive statistics, chi-square analysis, and qualitative content analysis were used to analyze responses.RESULTS:The survey response rate was 129/152 providers (85%). Forty-two percent of respondents described the quality of the handoff process as "very good" or "excellent"; 43% reported miscommunication occurring "sometimes" or "frequently." Within the I-PASS framework-Illness severity, Patient summary, Action list, Situation awareness and contingency planning, and Synthesis by receiver-respondents identified 10 key elements to obtain through a receiver-driven process to optimize care on transfer. Free-text responses revealed a perceived need to standardize communication.CONCLUSION:A minority of providers perceived handoff quality between outpatient practices and the ED as "very good" or "excellent"; almost half perceived regular miscommunication. A receiver-driven process is a novel approach that may help ensure standardized communication of key handoff elements in this context.

Introduction: The literature lacks data on accuracy of single fiber electromyography (SFEMG) for myasthenia gravis (MG) patients followed longitudinally. Methods: We included patients with a clinical suspicion of MG who received SFEMG and follow-up at our institution between 2003 and 2013. Data collected included demographics, symptom details, clinical deficits, other diagnostic testing results, MG medication regimen, duration on treatment, response to therapy, and ultimate diagnosis after follow-up. When available, information was also extracted from the MG-specific Activities of Daily Living, MG Quality of Life, and European Quality of Life assessments before and after SFEMG. Results: Three hundred forty eight SFEMG patients met inclusion criteria. Myasthenia gravis was ultimately diagnosed in 31% (19% ocular, 12% generalized). A sensitivity of 78% was seen for MG regardless of subtype, 73% for ocular MG, and 85% for generalized MG. A specificity of 91% was obtained for MG of either ocular or generalized subtype. Conclusions: The diagnostic accuracy of SFEMG using this methodology minimizing incorporation bias is more reliable than that usually described in previous studies. There is utility in increasing diagnostic yield when SFEMG results are combined with clinical data and those from other diagnostic tests, particularly serology.

Introduction: Antibody against the acetylcholine receptor of autonomic ganglia (gAChR‐Ab) is implicated in the pathogenesis of autoimmune autonomic ganglionopathy (AAG) and several other disorders. Methods: This study was a retrospective evaluation of 95 patients positive for gAChR‐Ab. Results: Twenty‐one (22%) patients had AAG, with a greater median gAChR‐Ab level (0.21 nmol/L) and higher percentage (57%) of antibody levels >0.20 nmol/L when compared with the remaining 74 patients without autonomic manifestations (non‐AAG group, 0.10 nmol/L and 15%, respectively). Only 2 new cases of malignancy were diagnosed after gAChR‐Ab detection. The non‐AAG group was associated with high frequencies of neurological and non‐neurological autoimmunity, but also included 23 (31%) patients with mostly degenerative disorders. Conclusion: Detection of gAChR‐Ab, especially at a higher level, is helpful for the diagnosis of AAG in patients with corresponding autonomic symptoms. However, its value is limited for predicting cancer risk and for diagnosis and management of patients without autonomic symptoms. Muscle Nerve 52:386–391, 2015

Introduction: Polyneuropathy evaluation in older patients is often challenging due to conflicting data regarding normative values for peripheral nerve testing. Methods: We characterized the results of sural nerve conduction studies, intraepidermal nerve fiber density (IENFD), and quantitative sudomotor axon reflex testing (QSART) in a prospective study of 50 healthy subjects aged 60 years. Results: Of the 50 subjects, 48 (96%) had an obtainable sural sensory nerve action potential (SNAP). Using quantile regression, we estimated the lower limit of normal (LLN) for sural amplitudes to be 3 V for patients 60-70 years, 1 V for those 70-74 years, and <1 V (absent) for those 75 years of age. IENFD and QSART volume were reduced with advancing age, although IENFD was lower in men and QSART volume was lower in women. Conclusions: We propose that an absent sural SNAP in patients up to 75 years of age should be considered abnormal. Our findings also support age- and gender-stratified normative data for IENFD and QSART. Muscle Nerve 49:564-569, 2014

Introduction: We report the electrodiagnostic (EDX) features of 32 patients with surgically verified true neurogenic thoracic outlet syndrome (TN-TOS). Methods: Retrospective record review. Results: We found uniform EDX evidence of a chronic axon loss process that affected the lower portion of the brachial plexus and disproportionately involved the T1 more than the C8 sensory and motor fibers. Because of this relationship, the medial antebrachial cutaneous sensory nerve (T1) and median motor (T1>C8) study combination was abnormal in 89%, whereas response combinations that primarily assessed the C8 fibers were less frequently affected. Conclusions: The characteristic EDX features of TN-TOS are T1>C8 nerve fiber involvement. A comprehensive EDX examination of the lower plexus with contralateral comparison studies is imperative to diagnose this disorder accurately. Muscle Nerve49: 724-727, 2014

Tentorial dural arteriovenous fistulas (TDAVFs) draining into the spinal venous system are rare lesions. The clinical presentation can be devastating and the diagnosis delayed because of the initial nonspecific imaging and laboratory findings. We report a case of a 20-year-old woman with a rapidly progressive myelopathy, who was found to have a left TDAVF, fed by a single arterial feeder with drainage into the perimedullary venous system. The fistula was surgically clipped. The patient showed neurologic improvement at her 3-month follow-up but still had significant weakness of all 4 extremities. Early diagnosis is key as the neurologic symptoms are reversible with appropriate treatment. We review the relevant literature, imaging characteristics, and treatment modalities for TDAVF.

Research into heart rate variability (HRV) and respiration over the past 150 years has led to the insight that HRV with deep breathing (HRVdb) is a highly sensitive measure of cardiovagal or parasympathetic cardiac function. This sensitivity makes HRVdb an important part of the battery of cardiovascular autonomic function tests used in clinical autonomic laboratories. HRVdb is a reliable and sensitive clinical test for early detection of cardiovagal dysfunction in a wide range of autonomic disorders.

Neuralgic amyotrophy (NA), or Parsonage–Turner syndrome, is an uncommon idiopathic disorder that occurs on a sporadic or hereditary basis. We describe the clinical and electrodiagnostic (EDX) features of NA in two siblings with documented Epstein–Barr virus (EBV) infections. This raises the possibility that a common infection may trigger NA in family members who possess a genetic disposition to this disease. Patient 1, a 20-year-old right-handed man, presented with fever, night sweats, and fatigue followed by aching pain in the right elbow and left shoulder. On day 11, he developed weakness in bilateral shoulder elevation, forearm pronation, right thumb flexion, right finger flexion, left wrist extension, and patchy sensory loss. The table contains laboratory and imaging results. IV solumedrol (900 mg/day for 3 days) did not provide relief. His weakness and pain continued to progress over 2 months, and a trial of IV immunoglobulin (IVIG; 400 mg/kg/day for 5 days) resulted in dramatic relief of pain. An EDX examination on day 62 showed evidence of severe to apparently complete …