Determination of sweat chlorides. Life of children with cystic fibrosis. Tips and practical recommendations from a pediatric gastroenterologist.

Note: The sweat conductivity test is not equivalent to the chloride concentration test. Sweat electrical conductivity indicator - screening test; value > 50 mEq/L is a quantitative indicator of chlorides in sweat. Conductivity is approximately 15 mEq/L, which is higher than the concentration in sweat.

Chloride concentration in sweat

>60 mEq/L on 2x measurements has a sensitivity of 90% with characteristic clinical findings or family history and confirms the diagnosis of cystic fibrosis.

Interpretation of results

Sweat testing is fraught with numerous technical and laboratory errors, so tests should be duplicated at least twice and different days, for the study taking > 100 mg of sweat.

Indicators in healthy individuals can be increased, as in patients with fibrous cystosis, and this increase is rapid (for example, when performing physical exercise, high temperature), but pilocarpine stimulation does not cause an increase in sweating.

Mineralocorticoids reduce the sodium concentration in sweat by approximately 50% in healthy people and by 10-20% in cystic fibrosis, in the latter case the final sodium concentration is significantly higher than normal.

Promotion

Endocrine disorders (eg, untreated adrenal insufficiency, hypothyroidism, vasopressin resistance, diabetes, familial hypoparathyroidism, pseudohypoaldosteronism).

Metabolic disorders (eg, nutritional disorders, glycogen storage disease type I, mucopolysaccharidosis IH or IS, fucosidosis).

Genitourinary disorders (eg, Klinefelter's syndrome, nephrosis).

Allergic-immunological diseases (for example, hypogammaglobulinemia, prolonged

prostaglandin E1 infusion, atopic dermatitis).

Neuropsychiatric diseases (for example, anorexia).

Others (eg, ectodermal dysplasia, G6PD deficiency).

Laboratory changes secondary to complications that also suggest the diagnosis of cystic fibrosis.

Respiratory disorders

Chronic diseases of the lungs (especially the upper lobes) with a decrease in p02, an increase in CO2, metabolic alkalosis, severe recurrent infection, cor pulmonale, also nasal polyps, pansinusitis; no changes in x-ray examination sinus significantly excludes cystic fibrosis.
Bronchopulmonary lavage typically reveals increased levels of polymorphonuclear leukocytes (compared to >50% in cystic fibrosis and 3% in healthy controls) with a significant increase in the absolute number of neutrophils, strongly indicating cystic fibrosis even in the absence of pathogens.
Bacteriological research requires special techniques. In 25% of children under 1 year of age, Staphylococcus aureus and pseudomonas are detected in 20% of cultures from the respiratory tract; in adults, pseudomonas grows in 80% of cases and S. aureus in 20%. N. influenzae is detectedin 3.4% of crops. Pseudomonas aeruginosa is found significantly more frequently after treatment of staphylococcal infections, and specific identification and presumption tests should be performed for P. auruginosa. Determination of P. cepacia infection is more significant in de. after one year of age. An increase in serum antibodies against P. aeruginosa may document suspected infection when culture results are negative.

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Cystic fibrosis of the pancreas - cystic fibrosis - an autosomal recessive disease caused by a gene mutation on chromosome 7, the main function of which is the regulation of the transport of water and salts, especially chlorides, through cell membranes through a special protein - the cystic fibrosis transmembrane regulator (CFTR).

Diagnostic criteria for cystic fibrosis

Must have at least one characteristic clinical symptom (respiratory, hyperhidrosis, gastrointestinal), or a sibling with cystic fibrosis, or a positive neonatal screen and sweat chloride greater than 60 mEq/L, or the presence of 2 CFTR genes, or a positive nasal transmembrane difference potential.

Quantitative pilocarpine iontophoresis sweat test (properly performed)

Significant concentration chlorides in sweat (more than 60 mEq/L) is constantly observed in cystic fibrosis. Increased sodium content (more than 60 mEq/L) or increased to a lesser extent; potassium is determined in almost all homozygotes, 3-5 times higher than in healthy individuals or patients with other diseases. They are determined from birth to death, and the degree of impairment does not depend on the severity of the disease or the involvement of the organ in the pathological process. The volume of sweat is not increased.

Sweat chlorides: 40-59 mEq/L, this level is considered borderline and requires further research. A reading of less than 40 mEq/L is normal. May be normal in non-classical cystic fibrosis. 2% of patients with cystic fibrosis have a reading of 60 mEq/L. In rare cases, patients with a borderline value of the indicator have a mild course of the disease.

Plasma potassium has no diagnostic value, since it partially covers normal values.

Different levels of sweat indicators can be found in patients with fibrous cystosis and in healthy people with minimal deviation.

Sweat indicators (average values are indicated, mEq/l):

1. Chlorides

Cystic fibrosis – 115 (79-148)
Norma 28 (8-43)

Cystic fibrosis 111 (75-145)
Norma 28 (16-46)

Cystic fibrosis - 23 (14-30)
Norm - 10 (6-17)

Note: The sweat conductivity test is not equivalent to the chloride concentration test. Sweat electrical conductivity indicator - screening test; a value of more than 50 meq/l is a quantitative indicator of chlorides in sweat. Conductivity is approximately 15 mEq/L, which is higher than the concentration in sweat.

Chloride concentration in sweat

The concentration of chlorides in sweat is more than 60 mEq/L measured twice has a sensitivity of 90% with characteristic clinical findings or family history and confirms the diagnosis of cystic fibrosis.

Interpretation of the test result for chlorides in sweat

Sweat testing is fraught with numerous technical and laboratory errors, so tests should be duplicated at least twice and on different days, taking more than 100 mg of sweat for the study.

Indicators in healthy individuals can be increased, as in patients with fibrous cystosis, and this increase is rapid (for example, during exercise, high temperature), but pilocarpine stimulation does not cause an increase in sweating.

Increased chloride concentration in sweat

Endocrine disorders (eg, untreated adrenal insufficiency, hypothyroidism, vasopressin resistance, diabetes, familial hypoparathyroidism, pseudohypoaldosteronism).
Metabolic disorders (eg, nutritional disorders, glycogen storage disease type I, mucopolysaccharidosis IH or IS, fucosidosis).
Genitourinary disorders (eg, Klinefelter's syndrome, nephrosis).
Allergic-immunological diseases (for example, hypogammaglobulinemia, prolonged infusions of prostaglandin E1, atopic dermatitis).
Neuropsychiatric diseases (for example, anorexia).
Others (eg, ectodermal dysplasia, G6PD deficiency).
Laboratory changes secondary to complications that also suggest the diagnosis of cystic fibrosis.

- Respiratory disorders

Chronic diseases of the lungs (especially the upper lobes) with a decrease in pO2, an increase in CO2, metabolic alkalosis, severe recurrent infection, cor pulmonale, also nasal polyps, pansinusitis; the absence of changes on x-ray examination of the sinus largely excludes cystic fibrosis.
Bronchopulmonary lavage usually reveals an increased content of polymorphonuclear leukocytes (for comparison: more than 50% in cystic fibrosis and 3% in healthy people) with a significant increase in the absolute number of neutrophils, which reliably indicates cystic fibrosis even in the absence of pathogens.
Bacteriological research requires special techniques. In 25% of children under 1 year of age, Staphylococcus aureus and pseudomonas are detected in 20% of cultures from the respiratory tract; in adults, pseudomonas grows in 80% of cases and S. aureus in 20%. H. influenzae is found in 3.4% of crops. Pseudomonas aeruginosa is found significantly more frequently after treatment of staphylococcal infections, and specific identification and presumptive tests should be performed for P. auruginosa. Determination of P. cepacia infection is more significant in children after one year of age. An increase in serum antibodies against P. aeruginosa may document suspected infection when culture results are negative.

- Gastrointestinal disorders

Chronic pancreatitis or acute recurrent pancreatitis.
Pancreatic insufficiency: up to one year of age more than 90%; in adults - 95%. Protein nutritional disorder, hypoproteinemia; impaired fat malabsorption with vitamin B deficiency in feces and duodenal contents indicates a lack of trypsin processing of gelatin; informative test up to 4 years of age; decreased production of chymotrypsin.
Altered glucose tolerance in 40% of patients with glucosuria and hyperglycemia in 8% of cases precede the development of diabetes.
Liver diseases, including cirrhosis, fatty liver, biliary tract stricture, cholelithiasis, etc. in 5% of cases. Neonatal cholestasis in 20% of children with this pathology can persist for months.
Meconium ileus in infancy is a cause of neonatal intestinal obstruction; detected at birth in 8% of children in this group. Almost all children will develop clinical signs of cystic fibrosis.
Increased incidence of gastrointestinal cancer.

Salt wasting syndrome

Hypochloremic metabolic alkalosis and hypokalemia due to excessive loss of electrolytes in sweat and stool.
Acute salt depletion.

Consequences of genitourinary tract abnormalities

Aspermia (complete absence of sperm according to spermogram results) in 98% of cases due to obstructive changes in the vas deferens and epididymitis, confirmed by testicular biopsy.
Serum chloride, sodium, potassium, calcium and phosphate are within normal limits until complications develop (for example, chronic lung diseases with CO2 accumulation, and massive loss of salts with profuse sweating can cause hypokalemia). Urine electrolytes are normal.
In the saliva of the submandibular gland there is a slight increase in chlorides and sodium, but not potassium; a significant excess of the norm prevents diagnostic use.
The saliva of the submandibular gland is cloudy, with increased levels of calcium, total protein and amylase. These changes are not usually detected in saliva from the parotid gland.
Serum protein electrophoresis reveals an increase in the content of IgG and IgA with the progression of the pulmonary disease; there is no noticeable increase in IgM and IgD.
Serum albumin is often low (due to hemodilution during the development of cor pulmonale; may be detected before clinically significant cardiac involvement in the pathology).

DNA genotyping (use of blood for analysis or scarification of the buccal mucosa) to confirm the diagnosis of cystic fibrosis, based on two mutations, is highly specific but not sensitive. A diagnosis of cystic fibrosis is suggested, but the absence of gene mutations does not exclude cystic fibrosis due to large quantity alleles. In a significant number of patients with cystic fibrosis, gene mutations cannot be identified. The study should be performed if sweat tests are borderline or negative. Can also be used to detect carrier status.

Genotype may be associated with the severity of the disease. Genotype cannot be used as the sole diagnostic criterion for cystic fibrosis.

Neonatal screening using dry filters to measure immunoreactive trypsin is used to confirm sweat tests or genotyping. The norm was noted in approximately 15% of infants, an increase in false-negative values with meconium ileus. Doctors cannot diagnose cystic fibrosis in 30% of children until the end of the first year of life.

Prenatal testing of chorionic villus samples in the first trimester or from amniocentesis in the second or third trimesters: more than 1000 mutations of the CFTR (cystic fibrosis transmembrane conductance regulator) gene, but only 25 are counted in approximately 90% of carriers. 52% are homozygous for aF508 and 36% heterozygous for dE508/other mutations.

Measuring electrical nasal potential differences may be more reliable than sweat tests, but is much more difficult: -46 mV in patients and -19 mV in healthy people.

Chlorides enter the body in the form of sodium, calcium, and magnesium salts, which, when dissolved, dissociate into chlorine cations and anions. Ionized chlorine plays an important role in maintaining acid-base balance and water balance in the body.

Normal concentration: in blood - 97-108 mmol/l, in urine - 150-250 mmol/day.

In healthy people, despite excess or insufficient intake sodium chloride(table salt), the normal concentration of chlorine ions in the blood is maintained due to the regulation of their excretion in the urine. The clinical significance of the determination of chlorides is the same as that of sodium.

An increase in the concentration of chlorides in the blood - a sign of dehydration - can occur with insufficient fluid intake, impaired urination due to kidney disease or blockage of the ureters, diabetes insipidus, respiratory alkalosis, or adrenal insufficiency.

A decrease in the concentration of chlorides in the blood occurs with excessive sweating, vomiting, respiratory and metabolic acidosis, the use of diuretics, and the appearance of edema.

Increased urinary excretion is observed with adrenal insufficiency, depletion of sodium reserves, chronic nephritis; reduced excretion - with the development of edema, fasting, vomiting, increased sweating.

The concentration of chlorides increases sharply in sweat and saliva in cystic fibrosis.

Chlorine, like sodium, is an extracellular element, so their determination has similar clinical significance, with the difference that physiological mechanisms maintain sodium concentrations within much narrower limits.
This happens because sodium is the main cation of extracellular fluids, accounting for 92-93% of all positive charges, while there are three main anions: chlorine, bicarbonate and organic acids, with chlorine accounting for only 2/3 of their total quantities. Although the sum of anions is also constant, like the sum of cations, the fluctuations of chlorine are relatively greater than those of sodium, since they are balanced by changes in other anions.

Determination of sodium in biological fluids using a flame photometer is simple and reliable; There is no similar method for chlorine, so sodium is determined in biochemical laboratories much more often than chlorine. However, in some cases, when it comes to the analysis of individual samples in small laboratories, especially when testing urine, the determination of chlorine is preferable, since it does not require almost any equipment. The simultaneous determination of both chlorine and sodium along with other inorganic plasma ions is sometimes used to calculate the organic acid content, which corresponds to the difference between the sums of inorganic cations and anions.

Chlorine is most often determined by titration, since, like other halogens, Cl– forms poorly soluble salts with silver and mercury ions.
The main methodological problem is how to determine the end of the titration, i.e. the appearance of excess silver or mercury. For this, electrochemical methods or back titration are used, when chlorine ions are precipitated by silver ions, and their excess is then titrated with thiocyanate ions, using iron salts as an indicator of the end of titration. However, the most practical is the direct method, in which mercury salts are added to the test solution and insoluble calomel precipitates. These methods are possible thanks to effective indicators for mercury - organic substances, the mercury salts of which are colored. When all the chlorine has been removed from the solution, new portions of the titrant color it. This is the basis for a unified method in which diphenylcarbazone is used as an indicator for mercury.

The most common methods for determining chlorine are instrumental methods that use coulometric titration. It involves measuring the amount of electricity required to remove all the chlorine from a solution.
The analysis boils down to the fact that a small amount of the test liquid (about 0.01-0.02 ml) - plasma, serum, urine or sweat - is diluted with a buffer solution containing nitric acid salts. Three electrodes are immersed in the solution: working, indicator and indifferent. A positive electric potential is applied to the working (silver) electrode, as a result of which a current flows through the solution, the amount of which is measured by a special electronic circuit- coulometer. The silver atoms on the working electrode are converted into Ag+ ions, which immediately react with Cl– ions, resulting in the precipitation of insoluble silver chloride. When all the chlorine is removed from the solution, the concentration in it increases sharply; this is detected by the indicator electrode, the signal from which stops the titration. The chlorine content in the sample is calculated using Faraday's formula, which relates the amounts electric current and the released silver, which was required to bind all the chlorine..

Sweating is the process of formation and secretion of uncolored liquid on the surface of the skin, which tastes salty. The role of sweating is extremely important for the normal functioning of the body's vital processes. Human sweat glands secrete a secretion (sweat) of liquid consistency onto the surface of the epidermis, the release of which to the outside through the pores ensures internal water-salt metabolism, regulates metabolism and cools the body. Sweat has a positive effect on the skin. Together with it, harmful toxins and substances are removed, and through its evaporation the process of thermoregulation is carried out.

Compound

Now let's find out what the composition of sweat is. If you make a short list, then 98-99% of sweat is a colorless liquid consisting of water, the remaining 1-2% is distributed into salts, urea, nitrogenous compounds and other waste products. The sodium and potassium salt content gives sweat a salty taste. Subsequently, they contribute to the release of chlorides, which are involved in maintaining normal water balance. When dehydrated, the body loses moisture and their concentration increases. With vomiting and excessive sweating, they, on the contrary, lose concentration and performance decreases.

Why is sweat analyzed for chlorides? The disease “cystic fibrosis” is often found in children; the result of the diagnosis depends on the analysis of chlorides. After a detailed chemical analysis, biologically active additives such as pheromones can be included in the sweat. 360 mg of nitrogen per day is excreted through sweat.

The level of sweating is influenced by the food included in the daily diet, the level of physical activity and the presence of diseases. Heat also affects the intensity of sweat production. The acid-base balance of sweat has a beneficial effect on the surface of the epidermis; when it is disturbed, harmful organisms appear.

Researchers Petrov I.M. and Petrov M.N. discovered that by analyzing the information of water that is present in sweat, information about human diseases can be obtained. This was published in the work “Information Analysis of Sweat” (magazine “Uspekhi modern natural science.” – 2007. – No. 6 – P. 85-86).

PH and specific gravity

Now you know what sweat consists of, let's look at its pH value. The fight against bacterial and fungal infections is supported by the normal acidic reaction of the skin. Alkaline irritants harm the epidermis with increased level acidity. Acidic sweat can leave stains on clothing that are difficult to remove. The lower the salt value, the more acidic the sweat produces. Under the influence of medications and physical activity The human body produces sweat with a lower acidity than perspiration at high temperatures.

Sweat glands located throughout the body, according to the formula for calculating pH, have a value in the range from 3.8 to 5.6, and the hollows of the armpits and groin area - in the range from 6.2 to 6.9. Specific gravity sweat is also calculated using a formula and its value ranges between 1.001 and 1.006, in rare cases reaching 1.010.

The causes of sweating can be different. For example, hyperhidrosis is accompanied by pronounced sweating, with the most unpleasant sour “aroma”. Vitamins B, E, and A are actively used in the treatment of this disease. Vitamin D deficiency increases the volume of sweat and can cause the development of rickets in children.

Sweat volume

If we lost the ability to sweat, we could only live for half an hour! Every five minutes our temperature would increase by one degree, resulting in hyperthermia and death. If you've always thought that sweating is bad for you, it's time to change your mind.

How much sweat can the body remove? The sweat system provides continuous sweat production of 500 to 700 ml per day at all times. The volume of sweating in people in tropical climates can easily reach from 5 to 12 liters per day. Dehydration occurs when you sweat 3 liters per hour, this is the maximum.

Physiology - a quick overview

Sweating is not just water filtration, but a complex physiological process. There is noticeable and imperceptible sweating. Its intensity is affected by muscle loads or increased ambient temperature.

Prolonged, low-intensity work also increases the amount of sweat produced. In case of insufficiency of renal function, the normal functioning of the sweating system is irreplaceable. Physical labor reduces blood flow to the kidneys, there is a sharp decrease in pressure in the capillaries of the renal glomeruli and disruption of urine formation, but the process of sweating well compensates for the resulting deficiency, taking over the excretory process.

Evaporation of sweat is one of the tools of thermoregulation. This process cools sweaty areas. The mechanisms of thermal sweating in a calm state and in a state of emotional arousal and elevated temperature differ. Let's briefly consider this difference using our own example. We are all familiar with the “cold” emotional sweat and sweat that is released when playing sports or when exposed to fluctuations in ambient temperature.

There are apocrine (large) and eccrine (small) sweat glands. If you add up their total size, you get a number equal in size to 5 square meters. m!

The task of apocrine cells is not directly related to thermal protection; their task is the humoral regulation of behavior. The specific fluid that this gland produces differs in composition, not only between men and women, but also among people of the same sex. The secretion is not produced all the time; it appears under the influence of various factors and phases of the menstrual cycle. Physiology has determined their place on our body - this is the groin zone and the hollows - the axillary zones. The substance that is secreted by them can attract or repel individuals of the opposite sex, and they themselves are always associated with body hair. The peak of their activity occurs during puberty and weakens throughout life, as they grow older and grow older.

What are the benefits of the eccrine glands? They increase the skin's ability to kill bacteria by producing compounds that make the epidermis acidic and play an important role. Their main task and benefit is the process of thermoregulation, the removal of toxins through the skin, the possibility of sweating in under stress and overheat protection.

Benefits of Sweating

Sweating is vital for humans. Normal operation of internal systems is impossible without it. We all do not tolerate the suffocating heat, the exhausting physical work, a state of stress or wild excitement. But, fortunately, life has provided us with a saving mechanism that cools and plays on our side and has a beneficial effect on vital processes.

Sweating occurs reflexively and is controlled nervous system. Skin thermoreceptors function as sensors for internal organs and muscles. When a sweaty person overheats, a signal comes to the rescue, which is immediately sent along the nerve pathways to the brain, right up to the nerve fibers.

A woman's sweaty scent has a more sour undertone, while a man's sweat smells unpleasant.

The answer lies in the characteristics of male and female metabolism, which have characteristic features. The female body characterized by the presence of saprophytes - substances related to cocci, because of this, a woman’s sweaty aroma has a more sour tint, and lipophilic diphtheroids are responsible for the smell of male sweating, which is why it smells so unpleasant. Women's apocrine glands are less active than men's.

Corresponding member of the Russian Academy of Medical Sciences, Professor Yu. V. Lobzin, talks in more detail about the smell of sweat in his work (where the researcher proves that even soap affects this parameter.

Cystic fibrosis – cystic fibrosis- an autosomal recessive disease caused by a gene mutation on chromosome 7, the main function of which is the regulation of the transport of water and salts, especially through cell membranes through a special protein - the cystic fibrosis transmembrane regulator (CFTR).

Diagnostic criteria

Quantitative pilocarpine iontophoresis sweat test (properly performed)

Significant concentration chlorides in sweat(more than 60 mEq/L) is constantly observed in cystic fibrosis. Increased content (more than 60 meq/l) or increased to a lesser extent; determined in almost all homozygotes, 3-5 times higher than in healthy individuals or patients with other diseases. They are determined from birth to death, and the degree of impairment does not depend on the severity of the disease or the involvement of the organ in the pathological process. The volume of sweat is not increased.

Sweat chlorides: 40-59 mEq/L, this level is considered borderline and requires further study. A reading of less than 40 mEq/L is normal. May be normal in non-classical cystic fibrosis. 2% of patients with cystic fibrosis have a reading of 60 mEq/L. In rare cases, patients with a borderline value of the indicator have a mild course of the disease.

Plasma potassium has no diagnostic value, since it partially covers normal values.

Different levels of sweat indicators can be found in patients with fibrous cystosis and in healthy people with minimal deviation.

Sweat indicators (average values are indicated, mEq/l):

1. Chlorides

Cystic fibrosis – 115 (79-148)
Norma 28 (8-43)

Cystic fibrosis 111 (75-145)
Norma 28 (16-46)

Cystic fibrosis - 23 (14-30)
Normal - 10 (6-17)

Chloride concentration in sweat

Decoding the analysis result

Sweat testing is fraught with numerous technical and laboratory errors, so tests should be duplicated at least twice and on different days, taking more than 100 mg of sweat for the study.

Increased chloride concentration in sweat

Endocrine disorders (eg, untreated adrenal insufficiency, hypothyroidism, resistance to diabetes, familial hypoparathyroidism,).
Metabolic disorders (eg, nutritional disorders, glycogen storage disease type I, IH or IS, fucosidosis).
Genitourinary disorders (eg, Klinefelter's syndrome, nephrosis).
Allergic-immunological diseases (for example, prolonged infusions of prostaglandin E1, atopic dermatitis).
Neuropsychiatric diseases (for example, anorexia).
Others (eg, ectodermal dysplasia, G6PD deficiency).
Laboratory changes secondary to complications that also suggest the diagnosis of cystic fibrosis.

— Respiratory disorders

Chronic diseases of the lungs (especially the upper lobes) with a decrease in pO2, an increase in CO2, metabolic alkalosis, severe recurrent infection, cor pulmonale, also nasal polyps, pansinusitis; the absence of changes on x-ray examination of the sinus largely excludes cystic fibrosis.
Bronchopulmonary lavage usually reveals an increased content of polymorphonuclears (for comparison: more than 50% in cystic fibrosis and 3% in healthy people) with a significant increase in the absolute amount, which reliably indicates cystic fibrosis even in the absence of pathogens.
Bacteriological research requires special techniques. In 25% of children under 1 year of age, Staphylococcus aureus and pseudomonas are detected in 20% of cultures from the respiratory tract; in adults, pseudomonas grows in 80% of cases and S. aureus in 20%. H. influenzae is found in 3.4% of crops. Pseudomonas aeruginosa is found significantly more frequently after treatment of staphylococcal infections, and specific identification and presumptive tests should be performed for P. auruginosa. Determination of P. cepacia infection is more significant in children after one year of age. An increase in serum antibodies against P. aeruginosa may document suspected infection when culture results are negative.

— Gastrointestinal disorders

or acute recurrent.
Pancreatic insufficiency: up to one year of age more than 90%; in adults - 95%. Protein nutritional disorder, hypoproteinemia; fat disorder with vitamin B deficiency in feces and duodenal contents indicates a lack of trypsin processing of gelatin; informative test up to 4 years of age; decreased production of chymotrypsin.
Altered tolerance to glucosuria in 40% of patients and hyperglycemia in 8% of cases precede the development of diabetes.
Liver diseases, including cirrhosis, fatty liver, biliary tract stricture, cholelithiasis, etc. in 5% of cases. in 20% of children with this pathology it can persist for months.
Meconium ileus in infancy is a cause of neonatal intestinal obstruction; detected at birth in 8% of children in this group. Almost all children will develop clinical signs of cystic fibrosis.
Increased incidence of gastrointestinal cancer.

Salt wasting syndrome

Hypochloremic and hypokalemia due to excessive loss of electrolytes in sweat and stool.
Acute salt depletion.

Consequences of genitourinary tract abnormalities

Aspermia (complete absence of sperm according to the results) in 98% of cases due to obstructive changes in the vas deferens and epididymitis, confirmed by testicular biopsy.
Serum chlorides, sodium, potassium, and within normal limits until complications develop (for example, chronic lung diseases with the accumulation of CO2, and massive loss of salts with profuse sweating can cause hypokalemia). Urine electrolytes are normal.
In the saliva of the submandibular gland there is a slight increase in chlorides and sodium, but not potassium; a significant excess of the norm prevents diagnostic use.
The saliva of the submandibular gland is cloudy, with an increased content of calcium, total protein and. These changes are not usually detected in saliva from the parotid gland.
Serum protein electrophoresis reveals an increase in the content of IgG and IgA with the progression of the pulmonary disease; there is no noticeable increase in IgM and IgD.
Serum levels are often low (due to hemodilution during the development of cor pulmonale; can be detected before clinically significant involvement of the heart in the pathology).

DNA genotyping(use for analysis or scarification of the buccal mucosa) to confirm the diagnosis of cystic fibrosis, based on two mutations, is highly specific but not sensitive. A diagnosis of cystic fibrosis is suggested, but the absence of gene mutations does not exclude cystic fibrosis due to the large number of alleles. In a significant number of patients with cystic fibrosis, gene mutations cannot be identified. The study should be performed if sweat tests are borderline or negative. Can also be used to detect carrier status.

Genotype may be associated with the severity of the disease. Genotype cannot be used as the sole diagnostic criterion for cystic fibrosis.

Measuring electrical nasal potential differences may be more reliable than sweat tests, but is much more difficult: -46 mV in patients and -19 mV in healthy people.

Cystic fibrosis of the pancreas - cystic fibrosis was last modified: October 29th, 2017 by Maria Saletskaya