What Are the Signs of Cystic Fibrosis in Children?

Cystic fibrosis (CF), also known as sticky disease or mucous sticky disease, is an autosomal recessive genetic disorder in children and adults with systemic exocrine gland dysfunction. The disease can affect multiple systems, mainly involving the respiratory and digestive tracts, with the highest morbidity and mortality being lung lesions.

Basic Information

nickname

Sticky disease

English name

cystic fibrosis

Visiting department

Pediatrics

Common causes

Autosomal recessive disease

Common symptoms

Cough, sputum purulent, stuffy nose and runny nose, bloating, vomiting, and delayed fetal discharge, etc.

Causes of cystic fibrosis in children

Cystic fibrosis is an autosomal recessive genetic disease. The disease-causing gene of a child is located on the long arm of the seventh pair of chromosomes, and is generally larger than 250 kb of DNA. Encoding genes. There was a deletion in one of the segments which resulted in the deletion of phenylalanine at position F508. It is actually known that more than 100 genetic mutations can lead to the phenotype of CF. It is now possible to detect heterozygotes and perform prenatal diagnosis of individuals with F508 deficiency. This disease mainly affects epithelial tissues and affects secretion and absorption functions. Among them, cystic fibrosis gene (CFTR) protein is mainly related to chloride ion translocation. In clinically, 99% of these children have increased chloride ion concentration in sweat, but some scholars believe that CFTR is a direct or indirect The ion permeates the related molecules.

Clinical manifestations of cystic fibrosis in children

The three major clinical features are diffuse chronic obstructive pulmonary disease, pancreatic insufficiency, and sodium and chlorine concentrations in sweat 3 to 5 times higher than normal.

Respiratory tract performance

More than 90% of patients have recurrent chronic infections of the upper and lower airways, including chronic bronchitis, atelectasis, and recurrent pneumonia. May be associated with empyema, chronic sinusitis, and bronchiectasis. Pseudomonas aeruginosa and Staphylococcus aureus are common infections.

Older children may have increased coughing in the morning and after exercise, and most of the phlegm is purulent. Some children may be asymptomatic for a long time or only show a long-term acute respiratory infection. Capillary bronchitis is often accompanied by wheezing, which is most common within 1 year of age, and can occur with cough, persistent or paroxysmal wheezing, and rapid breathing. When the lung disease progresses or is repeatedly exacerbated, the cough persists, there is a lot of sputum, stickiness is not easy to cough, shortness of breath, and backward growth and development. Due to repeated infections, fever, restless sleep, and loss of appetite, children are becoming thinner. Pulmonary heart disease can eventually occur and death due to respiratory failure.

Nasal mucosal inflammation, edema, and nasal polyps can cause nasal congestion and runny nose. Acute sinusitis is uncommon, and nasal polyps are common in patients 5 to 20 years old.

Examination revealed barrel-shaped chests, shaved shoulders, depressions between the intercostals and clavicle, clubbing fingers (toes), cyanosis of lips and nails, and shortness of breath. On auscultation, there were wheezing sounds and dry and wet rales. As the survival rate of children has increased and the age of survival has increased in recent years, pneumothorax and hemoptysis are more common than in the past. Hemoptysis caused by ruptured aneurysm of bronchopulmonary artery shunt.

2. Digestive tract performance

In neonatal CF, 15% to 20% of meconium-induced intestinal obstruction and peritonitis occur, manifested by abdominal distension, vomiting, and delayed fecal discharge. Most children have symptoms of pancreatic insufficiency. The child has a good appetite. Although he consumes a sufficient amount of milk and complementary foods, he still does not gain weight and often cry because of hunger. There are many stools and a large amount of stool, and there is significant fatty diarrhea with a bad smell. The weight loss of the limbs is in sharp contrast to the swollen belly. Rectal prolapse often. Neonatal CF children may develop cholestatic jaundice with low liver function, and older children may develop cirrhosis, portal hypertension, and hypersplenism. Fatal gastrointestinal bleeding, pancreatic hyposecretion, and malabsorption may occur, such as hypoproteinemia, edema, malnutrition anemia, growth retardation, fat-soluble vitamin deficiency, hypolipemia, and hypocholesterolemia disease.

3. Other

Symptomatic bile duct sclerosis occurs in 2% to 3% of patients, with jaundice, ascites, and esophageal varices causing vomiting and hypersplenism. In addition to insufficient pancreatic exocrine glands, there may also be hyperglycemia, diabetes, polyuria, and weight loss. Gonadal development was delayed, with an average delay of 2 years. About 95% of men have azoospermia due to Wolffian tube development. The incidence of inguinal hernia, scrotal fluid, and undescended testicles was higher than in normal people. Women may have cervicitis. Toddlers may lose too much salt due to sweating, "salt cream" on the skin or a strange smell on the skin. Such children can manifest as hypochlorine alkalosis.

Pediatric Cystic Fibrosis

Blood gas analysis

Alveolar-arterial oxygen partial pressure difference increased, arterial PO ₂ decreased and CO ₂ retention.

2. sweat chloride test

The patient's sweat sodium chloride increased. The sweat collection method is the most accurate method using pilocarpine ion penetration method. Collect sweat after stimulating sweat glands (at least 0.1ml ~ 0.5ml). Then, the chlorine was measured by titration, and the sodium and potassium were measured by flame photometry. If adrenal insufficiency can be ruled out, sweat chloride value <40mmol / L (40mEq / L) is normal; 50-60mmol / L (50-60mEq / L) is suspicious; 60mmol / L (60mEq / L) or more The diagnosis is necessary to confirm the clinic. Sweat chloride> 60mmol / L (60mEq / L) is positive, and two sweat chloride tests are required.

3. Pancreatic dysfunction

Duodenal fluid is small and thick, pH is reduced, bicarbonate ions are low, trypsin is lacking or only a small amount, trypsin test is negative, chymotrypsin, trypsin and amylase are all low.

4. Fat malabsorption

Can be checked in the following ways:

(1) Check the urine for iodine after taking lipiodol. If it does not contain iodine, it means that the fat is not absorbed.

(2) Carotene or vitamin A is poorly absorbed. If a large amount of vitamin A is taken orally, repeated measurements of carotene or vitamin A can determine this condition.

(3) The serum cholesterol content is generally lower than that of ordinary people, which also indicates that fat is poorly absorbed.

5. Other inspections

Bacterial culture and isolation of lower airway secretions; detection of genetic mutations can be performed in prenatal testing and newborn screening.

6.X-ray inspection

(1) Early signs of chest radiographs are general emphysema and diffuse atelectasis in both lungs. Atelectasis is lobular or lobulous, the latter is more common in small infants, especially the upper right lobe. The signs of mucus embolism are "finger-like" bifurcated shadows that extend outward from the hilar area and are more common in the upper lobe. Most cases of pneumonia and small abscesses often occur during repeated infections, which can extend to the periphery of the lung. Bronchiectasis appears as scattered small cystic shadows. Hilar lymph nodes often swell. Pulmonary hypertension and pulmonary heart disease occur in the late stage, and pneumothorax can occur repeatedly.

(2) Dilated intestinal canal, fluid level, and nodules can be seen on plain abdomen , and ground glass can be seen in the middle and lower abdomen.

7.CT inspection

It can be seen that the bronchial wall is thickened, the mucus is embolized, the local air is too much, and the early bronchiectasis is dilated.

8. Lung function

Abnormal lung function at the early stage showed a decrease in vital capacity and a decrease in mid-expiratory flow rate, reflecting small airway obstruction. In the future, the tidal volume will decrease, the minute ventilation volume will decrease, the residual gas volume and functional residual gas volume will increase, the lung compliance will decrease, and the airway resistance will increase.

9. Determination of nasal mucosal cell potential difference

Diagnosis of cystic fibrosis in children

The diagnostic criteria for CF are:

1. Family history.

2. Typical lung disease (chronic obstructive pulmonary disease).

3. Pancreatic insufficiency.

4. Two positive sweat tests [sweat chloride> 60mmol / L (60mEq / L)], abnormal pancreatic function, poor fat absorption, and bacterial culture isolation of lower respiratory tract secretions.

At least two of the above can be diagnosed as cystic fibrosis, but a positive sweat test is necessary to confirm the clinic. New diagnostic criteria such as the detection of gene mutations and the determination of nasal mucosal cell potential differences.

Differential diagnosis of cystic fibrosis in children

The lung lesions of this disease should be distinguished from asthma, whooping cough, chronic bronchitis or recurrent bronchopneumonia, Staphylococcus aureus pneumonia, bronchiectasis and tuberculosis. The clinical manifestations of the digestive tract should be distinguished from neonatal intestinal atresia, infantile milk allergy, ₁ -antitrypsin deficiency, celiac disease, and protein loss bowel disease. In addition, it should be distinguished from familial autonomic nervous disorders, hypoglycemia, and other immunodeficiency diseases and liver cirrhosis.

Pediatric Cystic Fibrosis Treatment

1. Treatment of lung lesions

Ultrasonic nebulization and bronchopulmonary lavage can be used to inject drugs, such as acetylcysteine and antibiotics, inhaled bronchodilators, chest physiotherapy and postural drainage; bronchoscopy can also be used to attract and lavage, especially with atelectasis And mucus obstruction; use appropriate antibiotics if necessary. Patients with cystic fibrous pulmonary disease are susceptible to secondary P. aeruginosa infection, which can be prevented by multivalent P. aeruginosa vaccine. Recombinant deoxyribonuclease (DNase) can be used to aerosolize the secretions to prevent thinning of mucus plugs and reduce infection. In addition, the treatment of pulmonary complications: such as atelectasis, hemoptysis, pneumothorax, allergic aspergillosis, hypertrophic pulmonary osteoarthropathy, and respiratory failure, right heart failure, etc.

2. Treatment of gastrointestinal diseases

(1) Diet Therapy A high-calorie meal should be provided, which is 30% -50% higher than the calories calculated by age. Protein should be increased, generally 6-8g / kg per day. Fat mass should be slightly lower. Recipes should contain simple sugars such as sugar, glucose and sucrose without starch. should be given a variety of vitamins, especially a large amount of 10,000 U per day of vitamin A, a sufficient amount of complex vitamin B and vitamin E 100 to 200 U per day; infants under 2 years of age and children with prothrombin prolonged application of vitamin K. In order to make up for chloride loss, salt should be added to the diet.

(2) Pharmacotherapy takes 2 to 5 g of pancreatin preparation per day, and its dosage is satisfactory based on length and weight gain. Oxygen should be given to severe or acute authors.

(3) Treatment of gastrointestinal complications including meconium intestinal obstruction, distal intestinal obstruction syndrome and other causes of abdominal pain, gastroesophageal reflux, rectal prolapse, liver disease, pancreatitis, hyperglycemia, etc.

3. Gene therapy

Recently, foreign studies have introduced normal genes that can express CFTR into the airways to treat CF. Currently, it is still in clinical trials, and it will take time to really use it for treatment.

4. Other

Including treatment of nasal polyps, loss of salt and hypochloric alkalosis.