Cystic fibrosis of the pancreas

　　The etiology of pancreatic cystic fibrosis is not yet fully clear. It is generally believed to be a genetic defect, an autosomal recessive hereditary disease caused by a single gene or multiple gene abnormal mutations. Autosomal recessive inheritance only causes disease when the pathogenic gene is in a homozygous state (rr). In a heterozygous state (Rr), due to the presence of a normal dominant gene R, the effect of the pathogenic gene r cannot be expressed. However, such individuals do not develop the disease but can pass on the pathogenic gene r to offspring, becoming carriers. Offspring with genetic factors have a high probability of 25% for the occurrence of pancreatic cystic fibrosis, with equal total probabilities for males and females. This disease can almost account for 2% to 4% of autopsies.

　　Pancreatic cystic fibrosis is mainly a disorder of exocrine pancreatic function, leading to electrolyte imbalance and malnutrition, characterized by a clinical syndrome with secretion disorders of multiple organs, mucus accumulation, and obstruction. The involved organs are numerous, and the symptoms are complex, making it difficult to be summarized by a simple mechanism. Some believe that there is a disorder in the transport of calcium ions in the body, with a large accumulation of calcium ions in the cytoplasm and mitochondria, causing the sodium pump function of the cell membrane to be out of control and the reabsorption of calcium ions to decrease. High concentrations of calcium ions in the cytoplasm will affect the transcription of glycoproteins, causing changes in the mucus glycoprotein pattern, thereby altering the gel-sol gel state of the secreted mucus by the exocrine glands, resulting in increased viscosity and secondary obstructive disorders of the excretory tract systems of multiple organs (pancreas, biliary, lung, small intestine).

　　In 1944, Farber reported a decrease in pancreatic secretion and a lack of pancreatic enzymes (amylase, lipase, protease), which resulted in early digestive and absorptive disorders of proteins and fats; it can also make meconium become thick, colloidal material, causing the ileum to be blocked by grayish-white meconium masses. Approximately 10% to 15% of infants with pancreatic cystic fibrosis can develop meconium ileus, which can lead to secondary ileus, intestinal necrosis, intestinal perforation, and meconium peritonitis.

　　Due to the thick consistency of sputum inside the bronchus, the abnormal composition and physical and chemical properties of sputum, it is not easy to be excreted, leading to a series of respiratory system lesions of pancreatic cystic fibrosis, including bronchial obstruction, bronchitis, peribronchitis, obstructive emphysema, bronchiectasis, pulmonary insufficiency, and even pulmonary heart disease.

　　There are reports that patients with cystic fibrosis of the pancreas can generally achieve normal growth and development before the age of 10, but after the age of 10, their growth and development may be affected due to the aggravation of malnutrition and chronic obstructive pulmonary disease. Due to the cystic fibrosis of the pancreas, about 13% of adult patients can develop diabetes, and they are also prone to acute pancreatitis. If not treated or treated improperly, most of them die from pneumonia or right heart failure in infancy, and early treatment has a better prognosis.

　　The onset of symptoms of cystic fibrosis of the pancreas usually occurs within one year. Due to the cystic fibrosis of the pancreas, the secretion and enzyme concentration of the pancreas are significantly reduced. Some cases have a large amount of feces in the neonatal period, and the meconium can be a sticky, gelatinous black substance like soot, which is tightly adhered to the intestinal wall, causing meconium ileus or peritonitis. Some may not appear significant steatorrhea until several months later. The child has a good appetite and, despite consuming a sufficient amount of food, the weight does not increase and the growth is slow. The feces are abundant, not formed, and have a peculiar smell, occurring 3 to 6 times a day. Some children may develop liver cirrhosis, and secondary hypoproteinemia, edema, anemia, xerophthalmia, and vitamin K deficiency syndrome may occur.

　　Children often have respiratory tract infections, which are recurrent and may eventually lead to chronic bronchitis, bronchopneumonia, or bronchiectasis. Severe cases may develop pneumothorax or hemoptysis. In the late stage, respiratory failure, pulmonary heart disease, and heart failure are common. The sodium and chloride content in the sweat, tears, and saliva of the child increases. During sweating, a large amount of water and electrolytes are lost, which is prone to exhaustion.

　　There is currently no effective preventive measure for cystic fibrosis of the pancreas. Early detection and early diagnosis are the key to the prevention and treatment of the disease. Patients with cystic fibrosis of the pancreas should have regular meals three times a day, avoid drinking alcohol, and do not overeat.

　　Sweat test (sweat test) is the main diagnostic method for cystic fibrosis of the pancreas. The concentration of chloride and sodium in the sweat of patients is 2 to 5 times higher than that of normal people (normal Na+ 10-80 mmol/L; Cl- 6-60 mmol/L), which has significant diagnostic significance and the diagnostic accuracy can reach 99%.

　　1. Imaging examination

　　The abdominal X-ray film shows dilated and aerated small intestine at the upper end of the obstruction, with scattered small bubbles (soap bubble sign) in the meconium, which is a typical sign of meconium ileus and one of the important diagnostic criteria for patients with cystic fibrosis of the pancreas. In patients with meconium peritonitis, fine strips or patchy calcification shadows can also be seen on the plain film. In patients with incomplete intestinal obstruction, after swallowing contrast medium, the contrast medium is distributed in segmental or mass-like patterns, with uneven diameter of the intestine and rough and disordered small intestinal mucosa. Ultrasound and CT imaging show shrinkage of the pancreas, uneven surface, extensive fibrosis, cystic dilatation of the pancreatic duct, and shrinkage, sclerosis, and dilatation of intrahepatic bile ducts with stones. The gallbladder is also shrunken, and the spleen is enlarged.

　　2, Endoscopic examination

　　Laparoscopic examination can reveal hardening, fibrosis, and irregular nodular surface of the pancreas; liver enlargement caused by fatty degeneration, focal or diffuse cholestatic liver cirrhosis.

　　Fiberoptic duodenoscopy or esophageal varices can be seen, duodenal fluid is thick, ERCP造影 shows segmental cystic dilatation of the pancreatic duct. Rectoscopy shows large and dilated crypts, with a large amount of thick mucus retained.

　　3, Pathological examination

　　Currently, the progress of imaging technology, under the guidance of B-ultrasound or CT, pancreas and liver puncture biopsy is relatively safe. Under the microscope, the acinar and ductal structures of the pancreas are blocked by eosinophilic material, with hyperplasia of surrounding fibrous tissue and infiltration of inflammatory cells, and the liver tissue shows cholestatic liver cirrhosis changes and stone formation.

　　The diet of patients with cystic fibrosis of the pancreas should be reasonably balanced, paying attention to the proportion of carbohydrates, fats, and proteins. Carbohydrates should be the main part, and the amount of fats and proteins should be appropriate; consume easily digestible proteins such as lean meat, eggs, and fish; adopt reasonable cooking methods such as boiling, stewing, simmering, steaming, sautéing, and blanching, and do not use methods such as frying, frying, and stir-frying to prevent excessive secretion of pancreatic juice due to excessive food fat.

　　The main pathological and physiological changes of cystic fibrosis of the pancreas are dysfunction of pancreatic exocrine secretion; secretion disorders of multiple organs, mucus accumulation, and obstruction. Therefore, except for surgical treatment for intestinal obstruction and portal hypertension, only symptomatic treatment can be carried out through internal medicine.

　　One, Internal medicine treatment

　　1, Improve pancreatic function: Appropriate administration of pancreatin helps food absorption. Pancreatin preparations (pancreatin or multi-enzyme tablets) are convenient to take, 600-800mg orally before each meal, and the dose of pancreatin preparations should be appropriately increased by 3-4 times for severe symptoms. Pay attention to adjusting the diet of infants and young children, and provide low-fat, moderate amount of carbohydrates, high-protein, and high-calorie diet. Such as taking medium-chain triglycerides, hydrolyzed protein, glucose, a variety of vitamins (fat-soluble vitamin A, vitamin D should be given in double dose), trace element preparations, salts. Daily approximately need 836J (210cal)/kg of heat for infants, 627J (150cal)/kg for children. For severe cases, elemental diet or parenteral nutrition can be provided.

　　2, Preventing lung infections: Mucus blocking the bronchi is a basic pathological change in the respiratory system. Encouraging expectoration, posture drainage, steam inhalation, and ultrasonic atomization (with an appropriate amount of trypsin) inhalation are helpful for the excretion of thick sputum. If there is a large amount of mucus blocking the bronchi, tracheal suction or bronchoscope lavage is required. The significance of preventive application of antibiotics is not great, and it is now rarely used. Once coughing, shortness of breath, and fever rise, indicating respiratory tract infection, medication can be selected according to oral swabs and sputum culture and their drug sensitivity tests, generally requiring continuous medication for about 10 days. Pseudomonas aeruginosa infection is often the cause of death, and it should be timely treated with ciprofloxacin, carbenicillin, cefoperazone, and other broad-spectrum antibiotics.

　　3. Incomplete meconium ileus: Saline solution containing pancreatic enzymes, balanced fluid enema, and oral sorbitol, mannitol, and other mild laxatives can be used. There are reports of using diluted iohexol enema, which is believed to both provide intestinal X-ray imaging for diagnosis and dilute tenacious meconium, stimulate peristalsis to promote defecation. Teenage patients can take 10% N-acetylcysteine (mucolytic) orally; or 10% N-acetylcysteine plus pancreatic enzyme preparation enema. Most patients can relieve meconium ileus through enema.

　　4. Others: 1% to 2% of pediatric patients have diabetes mellitus, which can rise to 13% in adults, and insulin therapy is required. For patients with biliary cirrhosis, liver protection and bile duct promotion should be maintained.

　　Second, surgical treatment

　　1. Intestinal obstruction: Complete meconium ileus, combined with intestinal torsion, intestinal necrosis, and intestinal perforation, all require surgical treatment. For meconium ileus, incision to remove fecal mass, colostomy, and colectomy can be used to relieve obstruction.

　　(1) Removal of fecal mass: Incise the intestinal wall at the hard meconium mass, remove the fecal mass, and then rinse with isotonic solution to try to remove as much meconium as possible, and suture the intestinal wall.

　　(2) Colostomy: For patients with severe illness who are not suitable for long-term operations, a larger rubber tube can be placed at the proximal obstruction site for stoma creation and decompression, and postoperative lavage of tenacious meconium can be performed through this tube. If the condition permits, the obstructed intestinal loop can be incised first to remove the fecal mass, and then it can be extracted to perform a double-barrel intestinal stoma or Mikulicz ileostomy.

　　(3) Colectomy: Sometimes meconium is extremely tenacious and difficult to remove, and the obstructed intestinal loop containing a large amount of meconium can be excised and anastomosed (Bishop-Koop ileum-ileum end-to-side anastomosis). However, attention should be paid to the fact that the intestinal wall of meconium obstruction is very thin, and intestinal anastomosis is very difficult, and it should be done with caution.

　　2. Portal hypertension: Children with esophageal varices and bleeding should receive portosystemic shunt surgery in a timely manner.