scholarly journals Cystic fibrosis with normal sweat chloride concentration: case report

2003 ◽  
Vol 58 (5) ◽  
pp. 260-262 ◽  
Author(s):  
Luiz Vicente Ferreira da Silva Filho ◽  
Maria Helena de Carvalho Ferreira Bussamra ◽  
Cleyde Miriam Aversa Nakaie ◽  
Fabíola Villac Adde ◽  
Joaquim Carlos Rodrigues ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Genetic Disease ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Chloride Concentration ◽  
Rapid Decrease ◽  
Compound Heterozygous ◽  
Sweat Chloride ◽  
Sweat Testing ◽  
Chloride Concentrations

Cystic fibrosis is a genetic disease usually diagnosed by abnormal sweat testing. We report a case of an 18-year-old female with bronchiectasis, chronic P. aeruginosa infection, and normal sweat chloride concentrations who experienced rapid decrease of lung function and clinical deterioration despite treatment. Given the high suspicion ofcystic fibrosis, broad genotyping testing was performed, showing a compound heterozygous with deltaF508 and 3849+10kb C->T mutations, therefore confirming cystic fibrosis diagnosis. Although the sweat chloride test remains the gold standard for the diagnosis of cystic fibrosis, alternative diagnostic tests such as genotyping and electrophysiologic measurements must be performed if there is suspicion of cystic fibrosis, despite normal or borderline sweat chloride levels.

Evaluation of a cystic fibrosis screening system incorporating a miniature sweat stimulator and disposable chloride sensor.

1986 ◽  
Vol 32 (5) ◽  
pp. 850-853 ◽  
Author(s):  
W J Warwick ◽  
N N Huang ◽  
W W Waring ◽  
A G Cherian ◽  
I Brown ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Chloride Concentration ◽  
Test System ◽  
Sweat Test ◽  
Sweat Chloride ◽  
The Subject ◽  
New System ◽  
Chloride Concentrations ◽  
Cystic Fibrosis Screening ◽  
Center Study

Abstract A new sweat test (CF Indicator; Medtronic, Inc.) for cystic fibrosis (CF) features a compact, portable configuration of electrodes that dispense pilocarpine for iontophoresis. A disposable chloride sensor patch absorbs a specified volume of sweat, in which the chloride concentration is immediately determined as less than 40, 40-60, or greater than 60 mmol/L. We assessed the performance of the system in a five-center study, in relation to the clinical diagnosis and to the Gibson-Cooke sweat test (GCST) as a control test. With sweat chloride concentrations of less than or equal to 40 mmol/L defined as normal and greater than 40 mmol/L as indicating persons at risk for CF, the new system showed 91% specificity and 100% sensitivity for CF, as compared with 92.8% and 100%, respectively, for the GCST. When we used sweat chloride concentrations of less than or equal to 60 mmol/L as probably normal and greater than 60 mmol/L as probably indicative of CF, the new system showed a 99.1% specificity and 98.6% sensitivity, vs 97.8% specificity and 97.9% sensitivity for the GCST test. In both procedures, occasionally insufficient sweat was collected, and this appeared related to the age of the subject. We conclude that the new sweat test system is potentially useful in physicians' offices, in clinics, and similar settings.

Outcomes of Cystic Fibrosis Screening–Positive Infants With Inconclusive Diagnosis at School Age

PEDIATRICS ◽  
2021 ◽  
Author(s):  
Tanja Gonska ◽  
Katherine Keenan ◽  
Jacky Au ◽  
Annie Dupuis ◽  
Mark A. Chilvers ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Chloride Concentration ◽  
Predictive Biomarkers ◽  
School Age ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Sweat Chloride ◽  
Sweat Testing ◽  
Prospective Longitudinal ◽  
Cystic Fibrosis Transmembrane

BACKGROUND AND OBJECTIVES Cystic fibrosis (CF) screen–positive infants with an inconclusive diagnosis (CFSPID) are infants in whom sweat testing and genetic analysis does not resolve a CF diagnosis. Lack of knowledge about the health outcome of these children who require clinical follow-up challenges effective consultation. Early predictive biomarkers to delineate the CF risk would allow a more targeted approach to these children. METHODS Prospective, longitudinal, multicenter, Canada-wide cohort study of CF positive–screened newborns with 1 to 2 cystic fibrosis transmembrane conductance regulator gene variants, of which at least 1 is not known to be CF-causing and/or a sweat chloride between 30 and 59 mmol/L. These were monitored for conversion to a CF diagnosis, pulmonary, and nutritional outcomes. RESULTS The mean observation period was 7.7 (95% confidence interval 7.1 to 8.4) years. A CF diagnosis was established for 24 of the 115 children with CFSPID (21%) either because of reinterpretation of the cystic fibrosis transmembrane conductance regulator genotype or because of increase in sweat chloride concentration ≥60 mmol/L. An initial sweat chloride of ≥40 mmol/l predicted conversion to CF on the basis of sweat testing. The 91 remaining children with CFSPID were pancreatic sufficient and showed normal growth until school age. Pulmonary function as well as lung clearance index in a subgroup of children with CFSPID were similar to that of healthy controls. CONCLUSIONS Children with CFSPID have good nutritional and pulmonary outcomes at school age, but rates of reclassifying the diagnosis are high. The initial sweat chloride test can be used as a biomarker to predict the risk for CF in CFSPID.

Letter to the Editor

PEDIATRICS ◽  
1969 ◽  
Vol 43 (5) ◽  
pp. 905-906
Author(s):  
Aubrey Milunsky
Keyword(s):  
Cystic Fibrosis ◽  
Bone Marrow ◽  
Clinical Presentation ◽  
Pancreatic Insufficiency ◽  
Chloride Concentration ◽  
Letter To The Editor ◽  
Patient Reported ◽  
Sweat Sample ◽  
Chloride Concentrations

The patient reported in the foregoing letter is of particular interest in view of the recent observations on patients with tnisomy 21 and cystic fibrosis. The multiple possibilities that could explain the clinical presentation have no doubt been considered by the authors. However, the description of "hypoplastic thrombocytopenia" and later pancytopenia in this patient, associated with pancreatic insufficiency, leads to the serious consideration of Shwachman's syndrome (pancreatic insufficiency and bone marrow dysfunction). The wide discrepancy between the sodium and chloride concentrations in the sweat reported in their letter indicates that evaporation of water may have occurred from the sweat sample, leading to an apparently higher sodium and chloride concentration.

Test for the Concentration of Electrolytes in Cystic Fibrosis of the Pancreas Utilizing Pilocarpine by Iontophoresis, by Lewis E. Gibson and Robert E. Cooke,Pediatrics; 1959;24:545–549

PEDIATRICS ◽  
1998 ◽  
Vol 102 (Supplement_1) ◽  
pp. 230-231
Author(s):  
Victor Chernick
Keyword(s):  
Cystic Fibrosis ◽  
Filter Paper ◽  
Direct Injection ◽  
Heat Stroke ◽  
Chloride Concentration ◽  
Hot Water ◽  
Sweat Test ◽  
High Concentration ◽  
Sweat Chloride ◽  
Plastic Bag

Aim. To develop a method for stimulating sweating that is rapid, painless, and avoids the risk of heat stress. Background. Since the discovery that there is a high concentration of sodium and chloride in the sweat of patients with cystic fibrosis of the pancreas in 1953, the sweat test has been performed by placing the patient's body in a plastic bag with or without hot water bottles to stimulate sweating. This method is unsatisfactory because of complications such as hyperpyrexia and heat stroke. Direct injection of a cholinergic agent intradermally is painful and therefore not practical. Methods. A rheostat with a milliampere meter was constructed at a cost of ∼$7 that allowed the iontophoresis of pilocarpine into the skin using negative and positive (2-cm diameter) electrocardiography electrodes. The positive electrode was placed on the flexor surface of the arm over a filter paper soaked in 0.2 mL of 0.2% pilocarpine nitrate. Current (0.2 mA) was applied for 5 minutes and then sweat was collected onto a preweighed filter paper for 30 minutes. Sweat chloride was determined by a polarographic method. Sweat tests were performed on 25 patients with cystic fibrosis (CF), 17 asymptomatic relatives and 27 control patients. Patients with CF had sweat chloride concentration >80 mEq/L; relatives, 32.5 mEq/L (highest 57 mEq/L); and control subjects, 21.1 mEq/L (highest 60 mEq/L). Conclusions. The iontophoresis of pilocarpine into the skin is a rapid, painless, safe, and reliable method for stimulating sweating and facilitating the determination of sweat chloride concentration.

Negative Effects of Oral Fatty Acid Supplementation on Sweat Chloride in Cystic Fibrosis

PEDIATRICS ◽  
1979 ◽  
Vol 64 (1) ◽  
pp. 50-52
Author(s):  
John D. Lloyd-Still ◽  
Stuart H. Simon ◽  
Hans U. Wessel ◽  
Lewis E. Gibson
Keyword(s):  
Cystic Fibrosis ◽  
Fatty Acid ◽  
Sweat Rate ◽  
Chloride Concentration ◽  
Control Group ◽  
Safflower Oil ◽  
Negative Effects ◽  
Fatty Acid Supplementation ◽  
Acid Supplementation ◽  
Sweat Chloride

Essential fatty acid supplementation with oral safflower oil (1 gm/kg/day) to 11 cystic fibrosis patients (aged 6 months to 14 years) for one year produced no significant change in sweat chloride concentration (mEq/liter) or sweat rate (gm/min/m2). Addition of vitamin E (10 mg/kg/day) to the safflower oil had no effect on sweat chloride concentration or rate compared to placebo. No clinical improvement could be detected compared to a control group. These results do not support previous reports of the effects of fatty acid supplementation on sweat electrolyte concentrations in cystic fibrosis.

scholarly journals Variability of sweat chloride concentration in subjects with cystic fibrosis and G551D mutations

2017 ◽  
Vol 16 (1) ◽  
pp. 36-40 ◽  
Author(s):  
F. Vermeulen ◽  
C. Le Camus ◽  
J.C. Davies ◽  
D. Bilton ◽  
D. Milenković ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Chloride Concentration ◽  
Sweat Chloride

Relation of sweat chloride concentration to severity of lung disease in cystic fibrosis

2004 ◽  
Vol 38 (3) ◽  
pp. 204-209 ◽  
Author(s):  
Pamela B. Davis ◽  
Mark D. Schluchter ◽  
Michael W. Konstan
Keyword(s):  
Cystic Fibrosis ◽  
Lung Disease ◽  
Chloride Concentration ◽  
Sweat Chloride

Correlation of Sweat Chloride Concentration with Genotypes in Cystic Fibrosis Patients in Saguenay Lac-Saint-Jean, Quebec, Canada

1998 ◽  
Vol 31 (1) ◽  
pp. 33-36 ◽  
Author(s):  
Marc De Braekeleer ◽  
Christian Allard ◽  
Jean-Pierre Leblanc ◽  
Gervais Aubin ◽  
Fernand Simard
Keyword(s):  
Cystic Fibrosis ◽  
Chloride Concentration ◽  
Sweat Chloride

scholarly journals Nasal Potential Difference in Cystic Fibrosis considering SevereCFTRMutations

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Ronny Tah Yen Ng ◽  
Fernando Augusto de Lima Marson ◽  
Jose Dirceu Ribeiro ◽  
Antonio Fernando Ribeiro ◽  
Carmen Silvia Bertuzzo ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Statistical Analysis ◽  
Gold Standard ◽  
Healthy Subjects ◽  
Gene Sequencing ◽  
Potential Difference ◽  
Healthy Controls ◽  
Exact Tests ◽  
Sweat Chloride ◽  
Nasal Potential Difference

The gold standard for diagnosing cystic fibrosis (CF) is a sweat chloride value above 60 mEq/L. However, this historical and important tool has limitations; other techniques should be studied, including the nasal potential difference (NPD) test.CFTRgene sequencing can identifyCFTRmutations, but this method is time-consuming and too expensive to be used in all CF centers. The present study compared CF patients with two classes I-IIICFTRmutations (10 patients) (G1), CF patients with classes IV-VICFTRmutations (five patients) (G2), and 21 healthy subjects (G3). The CF patients and healthy subjects also underwent the NPD test. A statistical analysis was performed using the Mann-Whitney, Kruskal-Wallis,χ2, and Fisher’s exact tests,α=0.05. No differences were observed between the CF patients and healthy controls for the PDMax, Δamiloride, and Δchloride + free + amiloride markers from the NPD test. For the finger value, a difference between G2 and G3 was described. The Wilschanski index values were different between G1 and G3. In conclusion, our data showed that NPD is useful for CF diagnosis when classes I-IIICFTRmutations are screened. However, if classes IV-VI are considered, the NPD test showed an overlap in values with healthy subjects.

scholarly journals Case Report: Japanese Siblings of Cystic Fibrosis With a Novel Large Heterozygous Deletion in the CFTR Gene

2022 ◽  
Vol 9 ◽  
Author(s):  
Mayumi Kawase ◽  
Masato Ogawa ◽  
Takayuki Hoshina ◽  
Masumi Kojiro ◽  
Miyuki Nakakuki ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Direct Sequencing ◽  
Chloride Concentration ◽  
Conventional Polymerase Chain Reaction ◽  
Large Deletion ◽  
Heterozygous Deletion ◽  
Real Time Quantitative Pcr ◽  
Sweat Chloride ◽  
Exon 1 ◽  
Fecal Pancreatic Elastase

Cystic fibrosis (CF) is a rare disease in the Japanese. The most common CFTR variant in Japanese CF patients is a large heterozygous deletion that can easily avoid detection by standard gene sequencing methods. We herein report a novel large heterozygous deletion in the CFTR gene in Japanese siblings with CF. A genetic analysis was performed in two patients (9-year-old boy and 5-month-old girl) who were clinically diagnosed with CF because of the positive result for the rapid fecal pancreatic elastase antigen test and the elevation of the sweat chloride concentration. In addition to conventional polymerase chain reaction (PCR) and direct sequencing, multiplex ligation-dependent probe amplification (MLPA) was performed to check for a large deletion and duplication of the CFTR gene. Based on MLPA findings, the breakpoint of heterozygous deletion was identified by real-time quantitative PCR followed by the sequence of the amplified junction fragment. In MLPA, the numbers of the fragments corresponding to exons 1, 16, 17a, and 17b and 234 nt and 747 nt upstream from the translation initiation codon of exon 1 in the CFTR gene and exon 3 in the ASZ1 gene were reduced by almost half. The c.2908+1085_3367+260del7201 variant (exon 16-17b deletion) was identified in one allele. The other allele had a large 137,567-bp deletion from g.117,361,112 (ASZ1 3′ flanking region) to g.117,498,678 (CFTR intron 1) on chromosome 7. Since the deletion variant lacked the entire promoter region of CFTR, CFTR mRNA would not be transcribed from the allele, indicating it to be a novel pathogenic variant causing CF. As large mutations are frequently detected in Japanese CF patients, MPLA can be useful when searching for variants.

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