Abnormal Electrolyte Composition of Sweat in Cystic Fibrosis of the Pancreas

Abstract

The electrolyte composition of sweat secreted in response to a standard mild thermal stimulus was found to be abnormal in 43 patients with cystic fibrosis of the pancreas. Sodium and chloride concentrations in sweat were 2 to 4 times as high as those found in 50 patients with a variety of other diseases. Sweat potassium levels were also increased in cystic fibrosis of the pancreas although not to the same extent. In contrast, the amount of sweat was not significantly different in patients with fibrocystic disease of the pancreas and control patients. It was shown that pancreatic deficiency, chronic pulmonary disease and the administration of certain drugs do not per se affect the electrolyte composition of sweat. It was also demonstrated by metabolic studies that disturbances in renal and adrenal function are not responsible for the high sweat chloride and sodium in fibrocystic disease. The dissociation between increased electrolytes in the sweat and their very low levels in the urine during salt restriction are unique to this condition. The fact that the sweat glands do not retain salt effectively in hot weather, during salt restriction or when DCA is administered, points to a disturbance in the sweat glands themselves. This abnormality may not be pathognomonic of cystic fibrosis of the pancreas, but it is an expected finding. These disturbances in sweat composition together with preliminary observations of abnormal salivary gland secretion suggest that the secretory activity of many and perhaps all exocrine glands is affected in cystic fibrosis of the pancreas. The term "mucoviscidosis" does not seem justified in view of the fact that at least two nonmucus-secreting structures are affected in this condition. Massive salt loss through sweating in hot weather accounts satisfactorily for the "heat casualties" in cystic fibrosis of the pancreas. The mechanisms are discussed and it is emphasized that the symptoms are initiated by pure salt loss and the consequent reduction in extracellular fluid volume. Since the condition may, if not treated, lead to fatal cardiovascular collapse, it should be regarded as an acute medical emergency. Under the usual circumstances, serum electrolyte concentrations are normal in fibrocystic disease of the pancreas. In the presence of marked pulmonary dysfunction in this disease, the bicarbonate of the plasma is elevated and the chloride reduced in compensation. It is therefore necessary to demonstrate a lowered serum sodium as well as chloride to detect the massive salt loss which may occur in hot weather.

CFTR bearing variant p.Phe312del exhibits function inconsistent with phenotype and negligible response to ivacaftor

“…In addition, the father in Family B experienced multiple episodes of dehydration, volume depletion, and vomiting, very similar to the cases of heat prostration reported in children with CF during a summer heat wave in 1948 ( 25 ). As shown later, loss of salt from the sweat glands caused volume depletion and abnormally low serum sodium, chloride, and potassium in the children with CF ( 26 ), and we presume the same mechanism was responsible for the electrolyte abnormality episodes in the father of Family B. Of note are reports of 3 children who presented with dehydration and/or hypochloremic metabolic alkalosis (salt-loss syndrome) and were thereafter identified to have F312del (reported as ΔF311 or DF311) and other severe CF-causing variants ( 7 , 8 ).…”

Roll-to-Roll Gravure Printed Electrochemical Sensors for Wearable and Medical Devices

“…Following benchtop characterization in buffer solutions, we demonstrate that the printed electrode-based sensors are equally high performing in biofluids including sweat, urine, and saliva. Na + is chosen as the target analyte as its concentration in these biofluids is relevant to assessing kidney disease and heart failure among other health complications, as well as for monitoring electrolyte loss or dehydration during exercise. ,− Na + sensors are fabricated on the printed electrode arrays and characterized using multipoint calibration to determine their concentration-to-potential curve. This information is used to accurately covert the sensor signal to a concentration measurement for the sweat, urine, and saliva samples.…”

Point-of-care and self-testing for potassium: recent advances

“…Vairo et al (2017) showed that electrolyte concentration in sweat sampled following physical activity did not reflect concentrations in plasma. 70 This is not to underestimate sweat's utilityfor example, electrolyte composition of sweat is known to be abnormal in cystic fibrosissodium and chloride concentrations are much higher 71,72 and sweat chloride concentration is a common diagnostic tool for cystic fibrosis. 73 In health, electrolytes such as sodium and potassium could be related to hydration status, and characterization of sweat electrolytes of athletes could suggest modifications of diet and training habits.…”