Cerebral blood flow and end-tidal CO2 predict lightheadedness during head-up tilt in patients with orthostatic intolerance.

Orthostatic intolerance (OI) is a common problem. Reliable markers of OI are missing, as orthostatic blood pressure and heart rate poorly correlate with orthostatic symptoms. The objective of this study was to assess the relationship between orthostatic lightheadedness and cerebral blood flow. In this retrospective study patients with OI were evaluated at the Autonomic Laboratory of the Department of Neurology, Brigham and Women's Faulkner Hospital, Boston. The 10-minute head-up tilt test was performed as a part of autonomic testing. Orthostatic lightheadedness was evaluated at every minute of the head-up tilt. Heart rate, blood pressure, capnography, and cerebral blood flow velocity (CBFv) in the middle cerebral artery using transcranial Doppler were measured. Repeated-measures design with a linear mixed-effects model was used to evaluate the relationship between orthostatic lightheadedness and hemodynamic variables. Correlation analyses were done by calculating Pearson's coefficient. Twenty-two patients with OI were compared to nineteen controls. Orthostatic CBFv and end-tidal CO2 decreased in OI patients compared to controls (p < 0.001) and predicted orthostatic lightheadedness. Orthostatic heart rate and blood pressure failed to predict orthostatic lightheadedness. The lightheadedness threshold, which marked the onset of lightheadedness, was equal to an average systolic CBFv decrease of 18.92% and end-tidal CO2 of 12.82%. The intensity of lightheadedness was proportional to the CBFv and end-tidal CO2 decline. Orthostatic lightheadedness correlated with systolic CBFv (r=-0.6, p < 0.001) and end-tidal CO2 (r=-0.33, p < 0.001) decline. In conclusion, orthostatic CBFv and end-tidal CO2 changes predict orthostatic lightheadedness and can be used as objective markers of OI.

Mast Cell Activation Syndrome: current understanding and research needs.

Mast cell activation syndrome (MCAS) is a term applied to several clinical entities which have gained increased attention from patients and medical providers. While several descriptive publications about MCAS exist, there are many gaps in knowledge resulting in confusion about this clinical syndrome. Whether MCAS is a primary syndrome or exists as a constellation of symptoms in the context of known inflammatory, allergic, or clonal disorders associated with systemic mast cell (MC) activation is not well understood. More importantly, the underlying mechanisms and pathways that lead to MC activation in MCAS patients remain to be elucidated. The purpose of this manuscript is to summarize the known literature, identify gaps in knowledge, and highlight research needs. Several topics are covered: 1) Contextualization of MCAS and MCAS-like endotypes and related diagnostic evaluations; 2) Mechanistic research; 3) Management of typical and refractory symptoms, and 4) MCAS-specific education for patients and healthcare providers.

Mismatch between subjective and objective dysautonomia.

Autonomic symptom questionnaires are frequently used to assess dysautonomia. It is unknown whether subjective dysautonomia obtained from autonomic questionnaires correlates with objective dysautonomia measured by quantitative autonomic testing. The objective of our study was to determine correlations between subjective and objective measures of dysautonomia. This was a retrospective cross-sectional study conducted at Brigham and Women's Faulkner Hospital Autonomic Laboratory between 2017 and 2023 evaluating the patients who completed autonomic testing. Analyses included validated autonomic questionnaires [Survey of Autonomic Symptoms (SAS), Composite Autonomic Symptom Score 31 (Compass-31)] and standardized autonomic tests (Valsalva maneuver, deep breathing, sudomotor, and tilt test). The autonomic testing results were graded by a Quantitative scale for grading of cardiovascular reflexes, sudomotor tests and skin biopsies (QASAT), and Composite Autonomic Severity Score (CASS). Autonomic testing, QASAT, CASS, and SAS were obtained in 2627 patients, and Compass-31 in 564 patients. The correlation was strong between subjective instruments (SAS vs. Compass-31, r = 0.74, p < 0.001) and between objective instruments (QASAT vs. CASS, r = 0.81, p < 0.001). There were no correlations between SAS and QASAT nor between Compass-31 and CASS. There continued to be no correlations between subjective and objective instruments for selected diagnoses (post-acute sequelae of COVID-19, n = 61; postural tachycardia syndrome, 211; peripheral autonomic neuropathy, 463; myalgic encephalomyelitis/chronic fatigue syndrome, 95; preload failure, 120; post-treatment Lyme disease syndrome, 163; hypermobile Ehlers-Danlos syndrome, 213; neurogenic orthostatic hypotension, 86; diabetes type II, 71, mast cell activation syndrome, 172; hereditary alpha tryptasemia, 45). The lack of correlation between subjective and objective instruments highlights the limitations of the commonly used questionnaires with some patients overestimating and some underestimating true autonomic deficit. The diagnosis-independent subjective-objective mismatch further signifies the unmet need for reliable screening surveys. Patients who overestimate the symptom burden may represent a population with idiosyncratic autonomic-like symptomatology, which needs further study. At this time, the use of autonomic questionnaires as a replacement of autonomic testing cannot be recommended.

Head-down tilt reduces the heart rate in postural tachycardia syndrome in acute setting: a pilot study.

BACKGROUND: Reduced preload and thoracic blood volume accompany postural tachycardia syndrome (POTS). Head-down tilt (HDT) increases both preload and intrathoracic blood volume. The objective of this study was to assess the safety and efficacy of HDT in POTS in acute settings. METHODS: This retrospective study evaluated POTS patients. Analyzed data included heart rate, blood pressure, cerebral blood flow velocity (CBFv) in the middle cerebral artery, and capnography. The baseline supine hemodynamic data were compared with the data obtained at the second minute of the -10° HDT. A linear mixed-effects model was used to assess the effect of HDT on hemodynamic variables. RESULTS: The HDT was explored in seven POTS patients and an additional seven POTS patients without HDT served as controls. In the HDT arm, four POTS patients had overlapping diagnoses of myalgic encephalopathy/chronic fatigue syndrome (ME/CFS) and one patient had comorbidity of post-acute sequelae of SARS-CoV-2 infection (PASC). HDT lowered heart rate by 10% and increased end-tidal CO2 by 8%. There was no change in other cardiovascular variables. CONCLUSIONS: In the acute setting, HDT is safe. HDT reduces the heart rate presumably by modulating baroreflex by enhancing preload and stroke volume, which in turn increases thoracic blood volume with a net effect of parasympathetic cardiovagal activation and/or sympathetic withdrawal. This pilot study provides a foundation to proceed with longitudinal studies exploring the long-term effect of repetitive HDT in conditions associated with preload failure such as POTS, ME/CSF, and PASC.

Crocus sativus L. Extract (Saffron) Effectively Reduces Arthritic and Inflammatory Parameters in Monotherapy and in Combination with Methotrexate in Adjuvant Arthritis.

Rheumatoid arthritis (RA), an autoimmune disease, is characterized by inflammation that affects not only the liver but also other organs and the musculoskeletal system. The standard therapy for RA is methotrexate (MTX), which has safety limitations. The extract from Crocus sativus L. (saffron-SF) is also known for its anti-inflammatory effects. Therefore, we decided to investigate the potential benefit of SF in monotherapy via two doses (SF1-25 mg/kg of b.w.; SF2-50 mg/kg of b.w.) and in combination with MTX (0.3 mg/kg of b.w., twice a week) using adjuvant arthritis in rats. To evaluate these therapeutic settings, we used biometric, immunological, and biochemical parameters, as well as the relative gene expression of the mRNA in the liver. Our results showed a statistically significant increase in the experimental animals' body weight and the arthritic score (AS) on day 14 for monotherapy with SF1 and SF2. The change of hind paw volume (CHPV) was significant only for SF2 monotherapy on the 14th day of the experiment. A combination of SF1 and SF2 with MTX significantly modulated all the biometric parameters during the experimental period. Additionally, AS and CHPV improved considerably compared to MTX monotherapy on day 21. Furthermore, all monotherapies and combination therapies were significant for the biochemical parameter γ-glutamyl transferase (GGT) in the joint. GGT activity in the spleen was less pronounced; only MTX in combination with SF1 significantly modified this parameter. The higher dose of SF monotherapy (SF2) was similarly significant with respect to immunological parameters, such as plasmatic IL-17A, IL-1ß, and MMP-9 on day 21. The combination of both doses of SF with MTX significantly improved these immunological parameters, except for C-reactive protein (CRP), which was influenced only by the higher dose of SF2 in combination with MTX in plasma at the end of the experiment. A different effect was found for the relative expression of CD36 mRNA, where only SF1 significantly decreased gene expression in the liver. However, the relative gene mRNA expression of IL-1ß in the liver was significantly reduced by the SF monotherapies and the combination of both SF doses with MTX. Our findings showed SF's partial antiarthritic and anti-inflammatory potential in monotherapy, but the effect was stronger in combination with MTX.

The Long Road of Long COVID: Specific Considerations for the Allergist/Immunologist.

Long COVID (coronavirus disease 2019) syndrome, also known as post-acute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, is a new disorder that can develop after an acute infection with the SARS-CoV-2 virus. The condition is characterized by multiorgan system involvement with a wide range of symptoms that can vary in severity from mild to debilitating. Some of the common symptoms associated with long COVID syndrome include cardiovascular issues such as heart palpitations and chest pain; thrombotic events (eg, blood clotting disorders); metabolic problems (eg, type 2 diabetes); dysautonomia; paroxysmal orthostatic tachycardia syndrome; myalgic encephalomyelitis/chronic fatigue syndrome; reactivation of the Epstein-Barr virus; the presence of autoantibodies; chronic spontaneous urticaria (hives); and connective tissue diseases. Whereas long COVID syndrome can affect individuals from various backgrounds, certain populations may be at higher risk such as individuals of Hispanic and Latino heritage, as well as those with low socioeconomic status, although approximately one-third of affected patients have no known risk factors or preexisting conditions. Many survivors of COVID-19 struggle with multiple symptoms, increased disability, reduced function, and poor quality of life. Whereas vaccination has been the most significant intervention able to decrease the severity of acute SARS-Cov2 infection and curtail deaths, limited data are available related to its modulating effect on long COVID necessitating the need for further investigation. Furthermore, several inflammatory pathways have been proposed for the pathogenesis of long COVID that are the targets for ongoing clinical studies evaluating novel pharmacological agents. The purpose of the present report is to review the many factors associated with long COVID with a focus on those aspects that have relevance to the allergist-immunologist.

Daily intranasal insulin at 40IU does not affect food intake and body composition: A placebo-controlled trial in older adults over a 24-week period with 24-weeks of follow-up.

Centrally administered insulin stimulates the reward system to reduce appetite in response to food intake in animal studies. In humans, studies have shown conflicting results, with some studies suggesting that intranasal insulin (INI) in relatively high doses may decrease appetite, body fat, and weight in various populations. These hypotheses have not been tested in a large longitudinal placebo-controlled study. Participants in the Memory Advancement with Intranasal Insulin in Type 2 Diabetes (MemAID) trial were enrolled in this study. This study on energy homeostasis enrolled 89 participants who completed baseline and at least 1 intervention visit (42 women; age 65 ± 9 years; 46 INI, 38 with type 2 diabetes) and 76 completed treatment (16 women, age 64 ± 9; 38 INI, 34 with type 2 diabetes). The primary outcome was the INI effect on food intake. Secondary outcomes included the effect of INI on appetite and anthropometric measures, including body weight and body composition. In exploratory analyses, we tested the interaction of treatment with gender, body mass index (BMI), and diagnosis of type 2 diabetes. There was no INI effect on food intake or any of the secondary outcomes. INI also showed no differential effect on primary and secondary outcomes when considering gender, BMI, and type 2 diabetes. INI did not alter appetite or hunger nor cause weight loss when used at 40 I.U. intranasally daily for 24 weeks in older adults with and without type 2 diabetes.

Dropout risk and effectiveness of retention strategies in the Memory Advancement by Intranasal Insulin in Type 2 Diabetes (MemAID) Clinical Trial.

BACKGROUND: Effective recruitment and retention strategies are essential in clinical trials. METHODS: The MemAID trial consisted of 12 visits during 24 weeks of intranasal insulin or placebo treatment and 24 weeks of post-treatment follow-up in older people with and without diabetes. Enhanced retention strategies were implemented mid study to address high drop-out rate. Baseline variables used in Cox regression models to identify dropout risk factors were: demographics and social characteristics, functional measures, metabolic and cardiovascular parameters, and medications. RESULTS: 244 participants were randomized; 13 (5.3%) were discontinued due to adverse events. From the remaining 231 randomized participants, 65 (28.1%) dropped out, and 166 (71.9%) did not. The Non-retention group included 95 participants not exposed to retention strategies, of which 43 (45.2%) dropped out. The Retention group included 136 participants exposed to enhanced retention strategies, of which 22 (16.2%) dropped out. Dropout risk factors included being unmarried, a longer diabetes duration, using oral antidiabetics as compared to not using, worse executive function and chronic pain. After adjusting for exposure to retention strategies, worse baseline executive function composite score (p = 0.001) and chronic pain diagnosis (p = 0.032) were independently associated with a greater risk of dropping out. The probability of dropping out decreased with longer exposure to retention strategies and the dropout rate per month decreased from 4.1% to 1.8% (p = 0.04) on retention strategies. CONCLUSIONS: Baseline characteristics allow prediction of dropping out from a clinical trial in older participants. Retention strategies has been effective at minimizing the impact of dropout-related risk factors. TRIAL REGISTRATION: Clinical trials.gov NCT2415556 3/23/2015 (www. CLINICALTRIALS: gov).

In Vitro Anticancer Activity of the Light Stable Zinc Isotope (64Zn) Compounds.

BACKGROUND/AIM: Today, stable isotopes of zinc are actively used for diagnostic purposes in oncology. However, there is extremely limited data on the attempts to apply stable zinc isotopes in cancer therapy or about the molecular mechanisms of their effects on the biology of tumor cells. Therefore, in this in vitro research, we evaluated the cytotoxic activity of stable zinc isotope (64Zn) enriched compounds against malignant cells and determined the mechanisms of their action. MATERIALS AND METHODS: Malignant and non-malignant cells of different histogenesis were used as objects of the study. The effect of the Zn64aspartate, Zn64glutamate, and Zn64sulfate on cell viability in a comparative aspect was evaluated. Compounds containing 64Zn stable isotope enriched to 99.2%. Western blot analysis was used to determine the expression level of apoptosis regulatory proteins. RESULTS: Salts of 64Zn with amino acids had the most significant cytotoxic effect on malignant cells. The studied tumor cells, and especially MB16 melanoma cells were the most sensitive to the cytotoxic effects of Zn64aspartate. Zn64aspartate showed more significant cytotoxic activity than Zn aspartate (with natural isotope distribution) in the studied cell models. Zn64aspartate induced caspase-dependent cell death in A-549 cells and the p53-mediated apoptosis in melanoma cells. CONCLUSION: Malignant cells were more sensitive to the cytotoxic effect of the Zn64aspartate than normal cells. An increase in the intracellular concentration of 64Zn, and hence isotope mass balance changes, may lead to the suppression of the viability and proliferation of malignant cells. These results can become the basis for developing a new generation of anticancer drugs.

Phase 1 First-in-Human Dose Escalation and Dose Expansion Study of KLS-1 (64Zinc Aspartate) in Patients With Cancer and Neurodegenerative Diseases.

Background KLS-1 is zinc (Zn) aspartate enriched with isotope 64Zn to 99.2% mass fraction of total zinc. KLS-1 is intended as a novel therapeutic approach for patients with a variety of diseases including but not limited to different forms of cancer and neurodegenerative diseases. The purpose of this first-in-human study was to determine the maximum tolerated dose (MTD), safety, and pharmacokinetics (PK) in patients with medical disorders. Methods The study was designed as consisting of two consecutive parts: the dose escalation part and the dose expansion part. Adult patients with refractory glioblastoma, primary progressive aphasia/dementia, amyotrophic lateral sclerosis, Parkinson's disease (PD), and type 1 diabetes were included. KLS-1 formulated as a 10 mL water solution containing 26.42 mg/mL of 64zinc aspartate (that is equivalent to 5.184 mg/mL of 64Zn) was administered twice weekly in two-week cycles via two-hour intravenous (IV) infusion at various dose levels during the dose escalation part and twice weekly during five subsequent weeks in the dose expansion part. The study was conducted at Pan American Cancer Treatment Center (Tijuana, Mexico) in 2020 and had a duration of 10 months. Results A total of eight patients (all white/Caucasian) were enrolled in both parts of the study. A total of four patients who participated in the dose escalation part were dosed twice weekly at 1, 2, and 4 mg/kg in two-week cycles for each dose level with the dose increased to the next higher level in the subsequent cycle. Dose-limiting toxicities (DLTs) were defined at dose level 4 mg/kg due to treatment-emergent reversible adverse events that required medications for symptomatic relief. The most common drug-related toxicities that occurred in two or more patients (≥25%) were weakness (five patients), fatigue (four patients), dizziness (three patients), nausea (two patients), poor sleep (two patients), and abdominal discomfort (two patients). In the dose expansion part, a dose of 2 mg/kg administered twice weekly was investigated for five continuous weeks in four patients and was established as recommended phase 1b/2 dose. Systemic exposure to KLS-1 (area under the curve (AUC) and maximum serum concentration (Cmax)) increased from 1 to 4 mg/kg and showed a linear relationship. Conclusions Multiple doses of KLS-1 ranging from 1 to 2 mg/kg administered twice a week via intravenous infusion for up to five continuous weeks were safe and well tolerated in patients with different types of therapeutic conditions including but not limited to a few forms of cancer and Parkinson's disease, and the evaluated pharmacokinetic parameters exhibited favorable profile.

Correction: Phase 1 First-in-Human Dose Escalation and Dose Expansion Study of KLS-1 (64Zinc Aspartate) in Patients With Cancer and Neurodegenerative Diseases.

[This corrects the article DOI: 10.7759/cureus.29921.].

Clinical Trial-Ready Patient Cohorts for Multiple System Atrophy: Coupling Biospecimen and iPSC Banking to Longitudinal Deep-Phenotyping.

Multiple system atrophy (MSA) is a fatal neurodegenerative disease of unknown etiology characterized by widespread aggregation of the protein alpha-synuclein in neurons and glia. Its orphan status, biological relationship to Parkinson's disease (PD), and rapid progression have sparked interest in drug development. One significant obstacle to therapeutics is disease heterogeneity. Here, we share our process of developing a clinical trial-ready cohort of MSA patients (69 patients in 2 years) within an outpatient clinical setting, and recruiting 20 of these patients into a longitudinal "n-of-few" clinical trial paradigm. First, we deeply phenotype our patients with clinical scales (UMSARS, BARS, MoCA, NMSS, and UPSIT) and tests designed to establish early differential diagnosis (including volumetric MRI, FDG-PET, MIBG scan, polysomnography, genetic testing, autonomic function tests, skin biopsy) or disease activity (PBR06-TSPO). Second, we longitudinally collect biospecimens (blood, CSF, stool) and clinical, biometric, and imaging data to generate antecedent disease-progression scores. Third, in our Mass General Brigham SCiN study (stem cells in neurodegeneration), we generate induced pluripotent stem cell (iPSC) models from our patients, matched to biospecimens, including postmortem brain. We present 38 iPSC lines derived from MSA patients and relevant disease controls (spinocerebellar ataxia and PD, including alpha-synuclein triplication cases), 22 matched to whole-genome sequenced postmortem brain. iPSC models may facilitate matching patients to appropriate therapies, particularly in heterogeneous diseases for which patient-specific biology may elude animal models. We anticipate that deeply phenotyped and genotyped patient cohorts matched to cellular models will increase the likelihood of success in clinical trials for MSA.

Network autonomic analysis of post-acute sequelae of COVID-19 and postural tachycardia syndrome.

BACKGROUND: The autonomic nervous system (ANS) is a complex network where sympathetic and parasympathetic domains interact inside and outside of the network. Correlation-based network analysis (NA) is a novel approach enabling the quantification of these interactions. The aim of this study is to assess the applicability of NA to assess relationships between autonomic, sensory, respiratory, cerebrovascular, and inflammatory markers on post-acute sequela of COVID-19 (PASC) and postural tachycardia syndrome (POTS). METHODS: In this retrospective study, datasets from PASC (n = 15), POTS (n = 15), and matched controls (n = 11) were analyzed. Networks were constructed from surveys (autonomic and sensory), autonomic tests (deep breathing, Valsalva maneuver, tilt, and sudomotor test) results using heart rate, blood pressure, cerebral blood flow velocity (CBFv), capnography, skin biopsies for assessment of small fiber neuropathy (SFN), and various inflammatory markers. Networks were characterized by clusters and centrality metrics. RESULTS: Standard analysis showed widespread abnormalities including reduced orthostatic CBFv in 100%/88% (PASC/POTS), SFN 77%/88%, mild-to-moderate dysautonomia 100%/100%, hypocapnia 87%/100%, and elevated inflammatory markers. NA showed different signatures for both disorders with centrality metrics of vascular and inflammatory variables playing prominent roles in differentiating PASC from POTS. CONCLUSIONS: NA is suitable for a relationship analysis between autonomic and nonautonomic components. Our preliminary analyses indicate that NA can expand the value of autonomic testing and provide new insight into the functioning of the ANS and related systems in complex disease processes such as PASC and POTS.

Complications of endoscopic retrograde cholangiopancreatography / Az endoszkópos retrográd cholangiopancreatographia szövodményei

During the more than 50-year history of endoscopic retrograde cholangiopancreatography (ERCP), it has become an almost exclusively therapeutic procedure from a diagnostic method. This was the result of the evolution of far less invasive diagnostic procedures and the identification of its complications. Nowadays, being aware of these complications is fundamental. Remarkable knowledge has been gathered over the past decades about the risk factors, preventive methods and endoscopic treatments. A significant number of relevant publications from Hungarian authors can be found in this field. In our article, we summarize the complications of ERCP, their definitions, severity classifications, risk factors, prophylactic methods and endoscopic treatments.

MemAID: Memory advancement with intranasal insulin vs. placebo in type 2 diabetes and control participants: a randomized clinical trial.

BACKGROUND: This study aimed at assessing the long-term effects of intranasal insulin (INI) on cognition and gait in older people with and without type 2 diabetes mellitus (T2DM). METHODS: Phase 2 randomized, double-blinded trial consisted of 24 week treatment with 40 IU of INI (Novolin® R, off-label use) or placebo (sterile saline) once daily and 24 week follow-up. Primary outcomes were cognition, normal (NW), and dual-task (DTW) walking speeds. Of 244 randomized, 223 completed baseline (51 DM-INI, 55 DM-Placebo, 58 Control-INI, 59 Control-Placebo; 109 female, 65.8 ± 9.1; 50-85 years old); 174 completed treatment (84 DM, 90 Controls); 156 completed follow-up (69 DM). RESULTS: DM-INI had faster NW (~ 7 cm/s; p = 0.025) and DTW on-treatment (p = 0.007; p = 0.812 adjusted for baseline difference) than DM-Placebo. Control-INI had better executive functioning on-treatment (p = 0.008) and post-treatment (p = 0.007) and verbal memory post-treatment (p = 0.004) than Control-Placebo. DM-INI increased cerebral blood flow in medio-prefrontal cortex (p < 0.001) on MRI. Better vasoreactivity was associated with faster DTW (p < 0.008). In DM-INI, plasma insulin (p = 0.006) and HOMA-IR (p < 0.013) decreased post-treatment. Overall INI effect demonstrated faster walking (p = 0.002) and better executive function (p = 0.002) and verbal memory (p = 0.02) (combined DM-INI and Control-INI cohort, hemoglobin A1c-adjusted). INI was not associated with serious adverse events, hypoglycemic episodes, or weight gain. CONCLUSION: There is evidence for positive INI effects on cognition and gait. INI-treated T2DM participants walked faster, showed increased cerebral blood flow and decreased plasma insulin, while controls improved executive functioning and verbal memory. The MemAID trial provides proof-of-concept for preliminary safety and efficacy and supports future evaluation of INI role to treat T2DM and age-related functional decline.

Qpack-a Python package for QASAT-quantitative scale for grading cerebral blood flow, autonomic testing, and skin biopsies.

Quantitative grading of testing has research and clinical relevance. QASAT (quantitative scale for grading of cardiovascular reflex tests, transcranial Doppler, sudomotor testing, and small fiber densities from skin biopsies) is an objective instrument for grading dysautonomia, related small fiber neuropathy and cerebral blood flow. QASAT uses established autonomic tests (deep breathing, Valsalva maneuver, tilt test, sudomotor test) and skin biopsies for assessment of small fibers. Calculations of scores are complex. This paper presents a qpack-an open source software package that implements QASAT in a Python programming language. The qpack automatically generates reproducible scores of each test and reduces calculation errors. Datasets for verifying the correct qpack implementation are provided. The goal of qpack is to facilitate availability, reproducibility, and quality of autonomic studies and skin biopsies for assessment of small fibers. Qpack is easy to use with standard Python distributions, can be incorporated into routine clinical or research autonomic testing and it is freely available.

Mast cell disorders are associated with decreased cerebral blood flow and small fiber neuropathy.

BACKGROUND: Mast cell disorders including hereditary alpha tryptasemia (HαT) and idiopathic mast cell activation syndrome (MCAS) can be associated with neurologic symptoms such as orthostatic intolerance, pain, and cognitive impairment. The origin of these symptoms is not well understood. OBJECTIVE: To characterize neurologic findings in patients with HαT and MCAS through objective measurements. METHODS: Patients with a confirmed diagnosis of HαT or MCAS with neurologic symptoms were referred for standardized autonomic testing encompassing Valsalva maneuver, deep breathing, sudomotor and tilt tests with cerebral blood flow velocity (CBFv) determination, and skin biopsies for small fiber neuropathy (SFN). RESULTS: There were 15 patients with HαT (age 44.4 ± 15.9 years), 16 with MCAS (34.4 ± 15.5), and 14 matched controls who were evaluated. Baseline serum tryptase level was increased in patients with HαT when compared with patients with MCAS (14.3 ± 2.5 ng/mL vs 3.8 ± 1.8; P <.001) and neurologic symptoms were similar between the 2 groups. When compared with controls, orthostatic CBFv was reduced in HαT (-24.2 ± 14.3%; P <.001) and MCAS (-20.8 ± 5.5%; P <.001). Reduced nerve fibers consistent with SFN were found in 80% of patients with HαT and 81% of those with MCAS. Mild-to-moderate dysautonomia was detected in all patients with HαT and MCAS when results of sympathetic, parasympathetic, and sudomotor tests were combined. CONCLUSION: We provide evidence of reduced orthostatic CBFv and SFN associated with mild-to-moderate autonomic dysfunction in patients with HαT and MCAS. Our findings suggest that comprehensive autonomic testing may be helpful to explain neurologic symptoms and guide treatment in patients with HαT and MCAS.