Cystic fibrosis

Introduction to cystic fibrosis Cystic pulmonary fibrosis (CPF or CF) is a congenital disease with a family autosomal recessive hereditary. The typical clinical manifestation is that the child has repeated respiratory and pulmonary infections, and there is a manifestation of pancreatic exocrine glands, such as a large amount of fat. The initial symptoms of the respiratory tract are cough, mainly dry cough. The sputum is sticky and difficult to cough up. It is followed by paroxysmal cough and increased sputum. basic knowledge The proportion of illness: 0.025% Susceptible people: no special people Mode of infection: non-infectious Complications: bronchiectasis hemoptysis

Cause of cystic fibrosis

Gene mutation (35%):

Studies have shown that the occurrence of CF and the transmembrane regulatory factor gene (CFTR) mutation directly lead to P. aeruginosa infection, the direct consequence of P. aeruginosa infection is airway mucus obstruction and progressive lung tissue necrosis.

Genetic factors (30%):

Cystic pulmonary fibrosis (CF) is an autosomal recessive congenital exocrine gland disease, the most susceptible organ of the respiratory tract and gastrointestinal tract. At present, the research on the pathogenesis of CF has been at the molecular level. Patients with a specificity of 15% showed adequate pancreatic function and were functionally adequate. In other patients, pancreatic function was insufficient and functionally inadequate. Scientists in the United States and Canada believed that the gene of CF was the first to determine its site based only on binding analysis. The cloned gene (site gene) also showed that the CF gene is located on chromosome 7, next to the CF gene, around a region of about 1.5 million base pairs, due to "chromosome beating" and "chromosome shifting" technology. In combination, a 500 kb DNA was cloned, of which about 256 kb was the CF gene. A part of this gene was used as a probe for a cDNA library of mRNA derived from sweat gland duct cells, and these cells showed CF. The patient's salt transport function was lost, a positive clone was found, and the cDNA was sequenced. The cDNA is about 6000 bp in length and contains an open reading region and an encoded egg. Consistently, further studies comparing the cDNA sequences of normal humans and patients revealed an interesting mutation, a lack of 3 bases, resulting in the lack of a protein protein product, 508 and a phenylalanine base (CF508). This mutation is only visible in CF patients and has never been seen by normal people.

Pathological changes: due to the abnormal function of the exocrine glands, the secretions of the respiratory tract are increased and thick, and the damage of the cilia removal function causes the bronchial mucus to clog, followed by secondary infection. Under normal circumstances, the patient has no respiratory lesions at birth. Early bronchial gland hypertrophy, goblet cell degeneration, and then bronchial mucous glands secrete a thick secretion, so that mucociliary epithelial activity is inhibited, mucus drainage is not smooth, resulting in bronchial obstruction, secondary suppurative bronchitis, lung Inflammation, such as recurrent lung infection, can further cause atelectasis, lung abscess, bronchiectasis, especially cystic bronchiectasis, extensive pulmonary fibrosis and obstructive emphysema, pulmonary hypertension in the later stage, pulmonary origin Heart disease, heart failure, etc., the disease begins to occur in the right upper lobe bronchus, often invading the sub-bronchus and bronchioles, the bronchiectasis of these two parts, is the characteristics of this disease, cystic bronchiectasis can be seen under the microscope, gland duct Dilation and hypersecretion, inflammatory swelling of the bronchial wall, plasma cells and lymphocytes Run, pancreatic lesions have ductal dilatation in the early stage, epithelial cells flatten, and later cause pancreatic degeneration and fibrosis, and finally can induce diabetes, liver lesions and pancreas are similar, early bile duct dilatation, hyperplasia, a few develop portal cirrhosis The sweat gland structure and sweat viscosity are normal, but the increase of Na, K, Cl- concentration in sweat is also a characteristic of this disease. About 10% of children may cause meconium intestinal obstruction due to abnormal gastrointestinal secretion glands.

Pulmonary cystic fibrosis prevention

1. Prevent infection, strengthen exercise, enhance physical fitness, improve autoimmune function and regular life.

2, a reasonable diet can eat more high-fiber and fresh vegetables and fruits, balanced nutrition, including protein, sugar, fat, vitamins, trace elements and dietary fiber and other essential nutrients, meat and vegetables, diversified food varieties, Giving full play to the complementary role of nutrients in food is also helpful in preventing this disease.

Cystic fibrosis complications Complications bronchiectasis hemoptysis

If there is repeated hemoptysis in the case of bronchodilation, there may be cyanosis and clubbing in the later stage, often with serious complications such as pulmonary heart disease and heart failure.

Pulmonary cystic fibrosis symptoms Common symptoms Gas diffusion disorder Hair loss Difficult chest tightness Pulmonary fibrosis Dry cough heart failure Hemoptysis Pulmonary infection

1. The typical clinical manifestation is that children have repeated respiratory and pulmonary infections, and there are manifestations of pancreatic exocrine glands, such as a large number of fat stools, which can be clinically different. It responds to cystic pulmonary fibrosis at the molecular level. Specificity, 15% of children with residual pancreatic function are adequate, classified as adequate pancreatic function, these children are better than residual pancreatic insufficiency type, if other family members are involved, must obtain the family history of the patient, sometimes the baby is born When the pancreatic function is insufficient, the meconium can cause meconium ileus due to sticky meconium.

2, the initial symptoms of the respiratory tract are cough, mainly dry cough, phlegm sticky and not easy to cough up, after the occurrence of paroxysmal cough, increased sputum, due to respiratory infection, many children due to fever, and then hospitalized for further examination, by Asked about the medical history and the relevant examination was confirmed. Because the child's respiratory tract infection is serious, it is difficult to cough up and will not cough, so there may be hypoxia such as chest tightness, suffocation and difficulty in breathing. These symptoms can last for weeks or even In the month, many children have serious diseases, but they are diagnosed in their 10s. Cystic pulmonary fibrosis can also affect the reproductive system. Therefore, most of the sick men and women are infertile.

3, such as combined bronchodilation with repeated hemoptysis, late can have cyanosis and clubbing, often with serious complications such as pulmonary heart disease and heart failure, often died before the age of 10, on the contrary, if you can get early diagnosis and With reasonable comprehensive treatment, most patients can live to be more than 20 years old or even longer.

Examination of cystic fibrosis

1. The sweat test is positive.

2. Pancreas stimulation test:

Trypsin was measured and pancreatic enzyme decreased significantly or nearly normal, but bicarbonate was significantly reduced.

In addition to clinical symptoms, X-ray, CT, and MRI can provide a certain diagnostic basis for auxiliary examination.

3. X-ray inspection:

(1) Changes in lung texture: Early in the lesion, bronchiectasis is manifested by enhanced lung texture.

(2) lobular pneumonia-like changes: manifested as bronchial obstruction below the segment, infection, forming a small patchy blurred shadow.

(3) Lung field change: There is an annular shadow around the hilum, which is an important X-ray sign of the capsular cavity at the beginning of the bronchi. This annular shadow is an abnormal bronchiectasis, not a true cavity. More obvious, there may be signs of air accumulation in the lower lobe, which includes loss of peripheral blood vessel distribution and diaphragmatic lowering, and localized obstructive atelectasis, emphysema, lung abscess and pulmonary heart disease.

(4) bronchography: manifested as light, moderate columnar bronchiectasis, often occurs in the upper lobe of both lungs.

4. Chest CT examination:

(1) thickening of the bronchial wall, bronchiectasis: can be widely distributed in the leaves of both lungs, especially in the upper lobe of both lungs, bronchiectasis is mainly light, moderate columnar bronchiectasis, bronchial wall thickening can occur in expansion The bronchi can also occur in non-expanded bronchi, often with mild thickening, and smooth inside and outside the wall.

(2) diffuse emphysema of both lungs: the lung field density is low and uneven, and the severity of the lesions varies in different cases, especially in infants or children.

(3) bronchial mucus plug: due to mucus secretion retention in the trachea, depending on the bronchial direction of the mucus, the shape is different, mostly round, oval, tubular or tip pointing to the "V" shape of the hilum or " Y" shaped high-density shadow, uniform density, smooth and sharp edges, CT value is generally 15 ± 10HU, but the long-lasting mucus plug CT value can be as high as 40 ~ 80HU, enhanced scanning without reinforcement.

(4) Thin-walled balloon chamber: due to bronchiectasis, emphysema pulmonary alveolar and interstitial balloon swelling form cysts of different sizes, mainly distributed in the upper part of both lungs.

(5) Patchy shadow: manifested as infectious bronchopneumonia and sub-segment atelectasis, with patchy high-density shadows ranging from 1 to 3 cm in size, with more common or upper lung lesions in the upper lung field.

5. Chest MRI examination:

MRI shows that the pathological changes of cystic fibrosis in the respiratory system are caused by secretions blocking the bronchus and secondary infection. MRI can better show bronchial mucus emboli and pulmonary infectious lesions. Mucus emboli is slightly shorter and longer T1 abnormal signal. The signal is uniform, the edges are smooth and sharp, and its shape is different. The tip points to the hilum, and the secondary infection is mainly lobular pneumonia.

Diagnosis and differentiation of cystic fibrosis

Diagnostic criteria

A useful laboratory test for cystic pulmonary fibrosis is a quantitative test of the chlorpyrifos electroosmotic therapy, because there is a high concentration of NaCl in the sweat, in general, Cl-<60mmol/L, as measured C1-> 70mmol / L is positive, has diagnostic value, combined with children with pancreatic duct and other exocrine gland dysfunction, stool volume, and more fat, children are often prone to respiratory infections, respiratory mucus secretion increased, It is easy to cause airway obstruction, and combined with family history, X-ray, CT, MRI, etc. can still be diagnosed.

Differential diagnosis

Cystic bronchofibrosis often occurs with cystic bronchiectasis, so it needs to be differentiated from some diseases that cause cystic bronchiectasis. Cystic bronchiectasis is a complication of recurrent or chronic infection, and its performance can be similar to multiple cavities. It is not true. The cavity is a manifestation of multiple bronchiectasis with a cystic cavity.

1. Gamma globulin deficiency:

The patient is prone to recurrent bacterial infection, secondary airway obstruction and cystic bronchiectasis, sometimes difficult to identify with cystic pulmonary fibrosis, but the patient's blood gamma globulin is significantly reduced or lacking, and there is no high concentration in sweat NaCl exists and can therefore be identified.

2. Recurrent bacterial pneumonia:

Repeated episodes can cause bronchiectasis. In the early stage, this bronchiectasis can be cylindrical and reversible, but after multiple episodes of pneumonia, bronchial lesions can develop into varicose veins or cystic bronchiectasis, located in the lower lobe. Its characteristics, early chest X-ray infection is normal, with linear shadows on the bottom of the lungs, bronchial angiography can show bronchiectasis, when the bronchial dilation is further developed, it can be small cystic bronchiectasis, with high-resolution CT (HRCT) ) can be diagnosed instead of bronchography.

3. Allergic bronchopulmonary aspergillosis:

When asthma occurs, it may be accompanied by bronchial cystic dilatation, but generally the age of onset of this disease is later, there is no family history, fiber bronchoscopy can find the mycelium, glucocorticoids can be cured.

4. Tuberculous bronchiectasis:

Tuberculosis is another cause of cystic bronchiectasis. After long-term tuberculosis infection, cavities can occur in the lung tip and the whole lung. In addition to necrotic cavities, these transparent areas must also consider bronchiectasis, especially cystic bronchi. Dilatation, but the bronchiectasis caused by tuberculosis generally has symptoms of poisoning, such as low fever, night sweats, etc., tuberculosis can be found in the sputum, the disease will gradually improve through anti-tuberculosis treatment, so the clinical diagnosis is not difficult.

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