scholarly journals Novel methods of imaging and analysis for the thermoregulatory sweat test

2018 ◽  
Vol 125 (3) ◽  
pp. 755-762 ◽  
Author(s):  
Michael S. Carroll ◽  
David W. Reed ◽  
Nancy L. Kuntz ◽  
Debra E. Weese-Mayer
Keyword(s):  
Thermal Imaging ◽  
Neurological Disorders ◽  
Evaporative Cooling ◽  
Autonomic Nerve ◽  
Sweat Test ◽  
Standard Testing ◽  
Testing Protocol ◽  
Widespread Adoption ◽  
Sweat Testing ◽  
Thermoregulatory Sweat Test

The thermoregulatory sweat test (TST) can be central to the identification and management of disorders affecting sudomotor function and small sensory and autonomic nerve fibers, but the cumbersome nature of the standard testing protocol has prevented its widespread adoption. A high-resolution, quantitative, clean and simple assay of sweating could significantly improve identification and management of these disorders. Images from 89 clinical TSTs were analyzed retrospectively using two novel techniques. First, using the standard indicator powder, skin surface sweat distributions were determined algorithmically for each patient. Second, a fundamentally novel method using thermal imaging of forced evaporative cooling was evaluated through comparison with the standard technique. Correlation and receiver operating characteristic analyses were used to determine the degree of match between these methods, and the potential limits of thermal imaging were examined through cumulative analysis of all studied patients. Algorithmic encoding of sweating and nonsweating regions produces a more objective analysis for clinical decision-making. Additionally, results from the forced cooling method correspond well with those from indicator powder imaging, with a correlation across spatial regions of −0.78 (confidence interval: −0.84 to −0.71). The method works similarly across body regions, and frame-by-frame analysis suggests the ability to identify sweating regions within ~1 s of imaging. Although algorithmic encoding can enhance the standard sweat testing protocol, thermal imaging with forced evaporative cooling can dramatically improve the TST by making it less time consuming and more patient friendly than the current approach. NEW & NOTEWORTHY The thermoregulatory sweat test (TST) can be central to the identification and management of several common neurological disorders, but the cumbersome nature of the standard testing protocol has prevented its widespread adoption. In this study, images from 89 clinical TSTs were analyzed retrospectively using two novel techniques. Our results suggest that these improved methods could make sweat testing more reliable and acceptable for screening and management of a range of neurological disorders.

scholarly journals Disposition of MDMA and Metabolites in Human Sweat Following Controlled MDMA Administration

2009 ◽  
Vol 55 (3) ◽  
pp. 454-462 ◽  
Author(s):  
Allan J Barnes ◽  
Bruno S De Martinis ◽  
David A Gorelick ◽  
Robert S Goodwin ◽  
Erin A Kolbrich ◽  
...  
Keyword(s):  
Solid Phase ◽  
Random Order ◽  
Research Unit ◽  
Sweat Test ◽  
Test Results ◽  
Double Blind ◽  
Scientific Database ◽  
Sweat Testing ◽  
Clinical Research Unit ◽  
Sweat Tests

Abstract Background: Understanding the excretion of 3,4-methylenedioxymethamphetamine (MDMA) and metabolites in sweat is vital for interpretation of sweat tests in drug treatment, criminal justice, and workplace programs. Methods: Placebo, low (1.0 mg/kg), and high (1.6 mg/kg) doses of oral MDMA were given double-blind in random order to healthy volunteers (n = 15) with histories of MDMA use. Participants resided on the closed clinical research unit for up to 7 days after each dose. Volunteers wore PharmChek® sweat patches (n = 640) before, during, and after controlled dosing. Patches were analyzed by solid phase extraction and GC-MS for MDMA, methylenedioxyamphetamine (MDA), 4-hydroxy-3-methoxyamphetamine (HMA), and 4-hydroxy-3-methoxymethamphetamine (HMMA). Limits of quantification (LOQ) were 2.5 ng/patch for MDMA and 5 ng/patch for HMA, HMMA, and MDA. Results: MDMA was the primary analyte detected in 382 patches (59.7%), with concentrations up to 3007 ng/patch. MDA was detected in 188 patches (29.4%) at <172 ng/patch, whereas no HMMA or HMA was detected; 224 patches (35.0%) and 60 patches (9.4%) were positive for MDMA and MDA, respectively, at the 25-ng/patch threshold proposed by the Substance Abuse and Mental Health Services Administration. Conclusions: Sweat testing was shown to be an effective and reliable method for monitoring MDMA use in this controlled MDMA administration study. However, variability in sweat excretion suggests that results should be interpreted qualitatively rather than quantitatively. These data provide a scientific database for interpretation of MDMA sweat test results.

Standardized Autonomic Testing in Patients With Probable Radiation-Induced Afferent Baroreflex Failure

Hypertension ◽  
2021 ◽  
Author(s):  
Guillaume Lamotte ◽  
Elizabeth A. Coon ◽  
Mariana D. Suarez ◽  
Paola Sandroni ◽  
Eduardo Benarroch ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Pressure Monitoring ◽  
Sweat Test ◽  
Plasma Norepinephrine ◽  
Pressure Monitoring ◽  
Autonomic Testing ◽  
Baroreflex Failure ◽  
Radiation Induced ◽  
Thermoregulatory Sweat Test ◽  
Blood Pressure Lability

Injury of the afferent limb of the baroreflex from neck radiation causes radiation-induced afferent baroreflex failure (R-ABF). Identification and management of R-ABF is challenging. We aimed to investigate the pattern of autonomic dysfunction on standardized autonomic testing in patients with probable R-ABF. We retrospectively analyzed all autonomic reflex screens performed at Mayo Clinic in Rochester, MN, between 2000 and 2020 in patients with probable R-ABF. Additional tests reviewed included ambulatory blood pressure monitoring, plasma norepinephrine, and thermoregulatory sweat test. We identified 90 patients with probable R-ABF. Median total composite autonomic severity score (range, 0–10) was 7 (interquartile range, 6–7). Cardiovascular adrenergic impairment was seen in 85 patients (94.4%), increased blood pressure recovery time after Valsalva maneuver in 71 patients (78.9%; median 17.4 seconds), and orthostatic hypotension in 68 patients (75.6%). Cardiovagal impairment was demonstrated by abnormal heart rate responses to deep breathing (79.5%), Valsalva ratio (87.2%), and vagal baroreflex sensitivity (57.9%). Plasma norepinephrine was elevated and rose appropriately upon standing (722–1207 pg/mL). Ambulatory blood pressure monitoring revealed hypertension, postural hypotension, hypertensive surges, tachycardia, and absence of nocturnal dipping. Blood pressure lability correlated with impaired vagal baroreflex function. Postganglionic sympathetic sudomotor function was normal in most cases; the most frequent thermoregulatory sweat test finding was focal neck anhidrosis (78.9%). Standardized autonomic testing in R-ABF demonstrates cardiovascular adrenergic impairment with orthostatic hypotension, blood pressure lability, and elevated plasma norepinephrine. Cardiovagal impairment is common, while sudomotor deficits are limited to direct radiation effects.

How to perform and interpret the sweat test

2019 ◽  
Vol 105 (4) ◽  
pp. 230-235 ◽  
Author(s):  
Anthony Brown ◽  
Laura Jenkins ◽  
Alastair Reid ◽  
Anne Leavy ◽  
Glen McDowell ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Screening Programme ◽  
Autosomal Recessive Disease ◽  
Clinical Suspicion ◽  
Sweat Test ◽  
Western World ◽  
Physiological Basis ◽  
Common Life ◽  
Sweat Testing ◽  
Life Threatening

Cystic fibrosis (CF) is the most common life-threatening autosomal-recessive disease affecting Caucasians in the western world. The sweat test is the main diagnostic test for CF. It is indicated as part of the clinical assessment for infants that have picked up on the national neonatal screening programme. It may also be requested where clinical suspicion of a diagnosis of CF exists despite normal screening results. This article outlines the physiological basis behind sweat testing and the technical aspects of performing the test. Indications for performing the test are also considered. The article aims to provide clinicians with a guide to interpretation of results.

Thermoregulatory Sweat Test

2016 ◽  
pp. 643-657
Author(s):  
Robert D. Fealey
Keyword(s):  
Body Surface ◽  
Sweat Rate ◽  
The Body ◽  
Sweat Test ◽  
Report Generation ◽  
The Core ◽  
Before And After ◽  
Anterior Body ◽  
Total Body ◽  
Thermoregulatory Sweat Test

The thermoregulatory sweat test (TST) consists of giving a controlled heat and humidity stimulus to produce a generalized sweat response. The TST assesses the integrity of efferent sympathetic sudomotor pathways. The entire anterior body surface is tested for both pre- and post-ganglionic lesions. The TST can evaluate patients with symptoms of small-fiber neuropathy and demonstrate autonomic involvement in disorders such as multiple system atrophy, hyperhidrosis, and some skin disorders. An indicator powder placed on the body surface before heating provides visualization of sweating and non-sweating skin. The patient’s weight (before and after heating) and height allows calculation of total body sweat rate, and the slope of the core temperature rise with time provides an estimate of heat tolerance. Normal and abnormal TST patterns, report generation, and difficulties and pitfalls in test interpretation are described.

Chronic Sinusitis and a Negative Sweat Test in a Patient with Cystic Fibrosis

1995 ◽  
Vol 9 (4) ◽  
pp. 225-228 ◽  
Author(s):  
Todd T Kingdom ◽  
Kelvin C. Lee ◽  
Gerd J. Cropp
Keyword(s):  
Cystic Fibrosis ◽  
Unusual Case ◽  
Dna Analysis ◽  
Chronic Sinusitis ◽  
Carrier State ◽  
Sweat Test ◽  
Genetic Mutations ◽  
Dna Mutation ◽  
Sweat Chloride ◽  
Sweat Testing

The diagnosis of cystic fibrosis (CF) is based on sweat chloride and DNA mutation testing. A subset of CF patients may have normal sweat chloride levels, thus requiring DNA analysis for confirmation of the diagnosis. These patients may escape diagnosis if sweat testing is the only modality used for screening. Recently, the putative structural gene for CF was localized to chromosome 7. The delta-F508 mutation accounts for approximately 70% of the CF chromosomes identified in North American Caucasians. Over 400 identified mutations constitute the remainder. It is now possible to screen patients for the presence of many of these genetic mutations, thus establishing the diagnosis of CF or defining a carrier state. We report an unusual case of a 17-year-old male with chronic sinusitis, mild pulmonary disease, and pancreatic sufficiency with nondiagnostic sweat chloride levels diagnosed to have CF after DNA analysis. This technique may thus serve as an important tool that pediatricians and otolaryngologists can use to diagnose children suspected of having CF.

Implementation of a Quality Improvement Program to Improve Sweat Test Performance in a Pediatric Hospital

2014 ◽  
Vol 138 (7) ◽  
pp. 920-922 ◽  
Author(s):  
Barina Aqil ◽  
Aaron West ◽  
Michael Dowlin ◽  
Estella Tam ◽  
Cristy Nordstrom ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Quality Improvement ◽  
Test Performance ◽  
Sweat Test ◽  
Pediatric Hospital ◽  
Improvement Program ◽  
Sweat Chloride ◽  
Sweat Production ◽  
Sweat Testing ◽  
Set Up

Context.—All positive screening of newborns for cystic fibrosis using the dried blood spot 2-tiered immunoreactive trypsinogen/DNA method requires subsequent sweat chloride testing for confirmation. Obtaining an adequate volume of sweat to measure chloride is a challenge for many cystic fibrosis centers across the nation. The standard for patients older than 3 months is less than 5% quantity not sufficient (QNS) and for patients 3 months or younger is less than 10% QNS. Objective.—To set up a quality improvement (QI) program for sweat testing to improve QNS rates using the Wescor Macroduct (Wescor, Inc, Logan, Utah) method at Texas Children's Hospital's laboratory, Houston, Texas. Design.—Single-center study. Results.—Quantity not sufficient rates were evaluated for 4 months before and 8 months after implementation of the QI program for patients aged 3 months or younger and those older than 3 months. The QI program included changes in technician training, service, site of collection, mode of collection, weekly review, and forms to screen patients for medications that may alter sweat production. A marked improvement was observed in the rates of QNS, which declined considerably from 16.7% to 8.5% (≤3 months old) and from 9.3% to 2.2% (>3 months old) after implementation of the QI initiative in both age categories. Conclusion.—This report demonstrates the effectiveness of the QI program in significantly improving QNS rates in sweat chloride testing in a pediatric hospital.

The clinical thermoregulatory sweat test induces maximal seating

2001 ◽  
Vol 11 (4) ◽  
pp. 227-234 ◽  
Author(s):  
Caleb Hsieh ◽  
Kevin McNeeley ◽  
Thomas C. Chelimsky
Keyword(s):  
Sweat Test ◽  
Thermoregulatory Sweat Test
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