Cystic fibrosis

　　Cystic fibrosis (CF) is the most common genetic disease causing reduced life expectancy among whites, with an incidence rate of about 1 in 3300 white infants, 1 in 15300 black infants, and 1 in 32000 Asian American infants in the United States; 30% of patients are adults.

　　Cystic fibrosis (CF) is an autosomal recessive genetic disease that is the most common cause of reduced life expectancy among whites, with an incidence rate of approximately 1 in 3300 white infants, 1 in 15300 black infants, and 1 in 32000 Asian American infants in the United States; 30% of patients are adults. CF is a genetic disease characterized by autosomal recessive inheritance, with 3% of whites carrying the gene. The related gene is located on chromosome 7q (long arm) of the genomic DNA, encoding a membrane-associated protein known as the cystic fibrosis transmembrane conductance regulator (CFTR). The most common gene mutation, △F508, leads to the deletion of the phenylalanine residue at position 508 of the CFTR protein and occurs in about 70% of alleles; another 30% have more than 600 less common gene mutations. The function of CFTR is not yet clear, but it is obviously a part of the cAMP-regulated chloride ion channel and regulates the transport of chloride and sodium across the cell membrane. Heterozygotes have no abnormal clinical symptoms, but there are mild abnormalities in the transport of epithelial cell membranes.

　　Concurrent purulent angiitis and arthritis can occur. After the development of pneumonia and atelectasis, coughing intensifies, thick mucus is difficult to cough up, and there is a rapid breathing. If the patient coughs up a large amount of purulent sputum or accompanied by hemoptysis, it indicates the possibility of bronchiectasis and lung abscess. After extensive fibrosis and emphysema of the lungs, there is wheezing, dyspnea after activity, and spontaneous pneumothorax or mediastinal emphysema often occur. When symptoms of hypoxia and carbon dioxide retention appear, dyspnea intensifies, cyanosis occurs, and finally, respiratory failure and pulmonary heart disease can develop. Children can also experience intestinal obstruction and rectal prolapse. Insufficient pancreatic secretion leads to abdominal distension, abdominal bulging, and the excretion of a large amount of foamy, foul-smelling feces, symptoms of dyspepsia, and even steatorrhea and nitrogen overflow. Biliary obstruction can cause jaundice, and when complicated with liver cirrhosis, portal hypertension and hyperfunction of the spleen can occur. If infants sweat excessively, they can lose a large amount of electrolytes and water, which is prone to fainting.

　　1. Respiratory system manifestations

　　The respiratory system is mainly manifested as recurrent bronchitis and airway obstruction. Symptoms may appear within a few days after birth. Early symptoms may include mild cough, accompanied by pneumonia and atelectasis, followed by worsening cough, difficulty expectorating thick phlegm, and rapid breathing. If a large amount of purulent sputum or hemoptysis is coughed up, it may indicate the possibility of bronchiectasis and lung abscess. Clubbing of fingers (toes) is often observed during physical examination. After widespread fibrosis and emphysema of the lungs, wheezing, dyspnea on exertion, and spontaneous pneumothorax or mediastinal emphysema may occur. When symptoms of hypoxia and carbon dioxide retention appear, dyspnea intensifies, cyanosis occurs, and finally, respiratory failure and pulmonary heart disease may result.

　　2. Digestion and malnutrition

　　Newborns may have meconium plug due to increased intestinal mucus secretion and viscosity, as well as the lack of pancreatic enzymes affecting protein digestion, with about 10% experiencing this. Children can also develop intestinal obstruction and rectal prolapse. Insufficient pancreatic secretion leads to symptoms of indigestion such as abdominal distension, bulging abdomen, and the excretion of large amounts of foamy, foul-smelling feces. Even steatorrhea and nitrogen diuresis may occur. Vitamin deficiency, especially vitamin A deficiency, can lead to dry eye disease. Although patients have a strong appetite and sufficient dietary intake, they still suffer from malnutrition and delayed growth and development. Biliary obstruction can cause jaundice, and when complicated with liver cirrhosis, portal hypertension and hypersplenism may occur. Infants who sweat excessively and lose a large amount of electrolytes and water are prone to fainting.

　　3. Reproductive system manifestations

　　Cystic fibrosis can also affect the reproductive system. Because thick secretions often block the ducts connecting the testicles and prostate (the vas deferens), many male patients with cystic fibrosis become infertile. Compared with normal women, the reproductive ability of women with cystic fibrosis also decreases.

　　The course of the disease varies greatly, mainly depending on the extent of lung involvement. However, deterioration is inevitable, leading to exhaustion and ultimately death, usually caused by respiratory failure and pulmonary heart disease. The therapeutic effect of nourishing the lung qi to enhance immunity through diet is worth recognizing. However, when eating, it is important to first understand the medicinal effects of the food, such as radish for those with excessive phlegm and coughing; lily for making porridge or drinking water; mung bean for those with excessive internal heat; and water chestnut can clear heat and generate fluid, which can be eaten raw or cooked. At the same time, due to the great differences in individual quality, it is necessary to choose food according to one's own condition and avoid eating too spicy, salty, greasy, and other foods.

　　Increased chloride in sweat, 80% to 85% of the pancreas's various exocrine functions are impaired, 5% to 10% have partial exocrine dysfunction, and a small part have normal exocrine function. The main manifestations of pancreatic insufficiency are steatorrhea and excessive nitrogen in feces.

　　Fat-soluble vitamins such as vitamin A, D, E, and K have malabsorption, vitamin K deficiency can occur at 1 year of age, with a tendency to bleed, low serum vitamin A levels, normal or slightly elevated levels in the liver, and symptoms such as night blindness and increased intracranial pressure may occur.

　　Normal liver function tests may have elevated direct bilirubin, elevated serum ALT, AST, and alkaline phosphatase, and some children may develop hypoproteinemia due to malabsorption.

　　Dietary Precautions:

　　Eat less spicy, fried, and other irritant greasy foods: It is necessary to eat light in daily life, especially for overweight patients, the amount of fat supply should be low. Eat meat with lean meat as the preference to achieve the purpose of removing phlegm and dampness and appropriately controlling weight. Spicy, fried, and other foods are easy to produce phlegm, lead to heat assisting evil, evil heat retained internally and not reaching, which can eventually lead to disease and heat ascending to the lung, aggravating the condition.

　　Medications that stimulate bile secretion are ineffective. There have been reports of successful treatment with saline lavage of the extrahepatic bile ducts. For patients with portal hypertension, if respiratory function is good, portosystemic shunt surgery can be performed. If respiratory function fails, bleeding from esophageal varices can only be treated with sclerotherapy or ligation. For lung infections in patients with cystic fibrosis, the new generation of antibiotics may be more effective, such as antibiotic sprays, which can directly deliver the drug to the airway for action. One of the biggest problems with long-term use of antibiotics is that bacteria may develop drug resistance, making antibiotics gradually ineffective. In addition, long-term use of antibiotics will increase the risk of fungal infections in the mouth, throat, and respiratory tract.