alveolar microlithiasis
Introduction
Introduction to alveolar microlithiasis Pulmonary alveolar microlithiasis (PAM) is a rare disease in which there are diffusely distributed tiny stones containing calcium and phosphorus. basic knowledge The proportion of illness: 0.007%-0.008% Susceptible people: no special people Mode of infection: non-infectious Complications: pulmonary hypertension, respiratory failure
Cause
Causes of alveolar microlithiasis
The cause of this disease is unknown.
Systemic metabolic disease (30%):
The patient had no history of chronic infection, history of allergies or occupational history. It is thought that it may be the lung performance of systemic metabolic diseases, but the closely related indicators of calcium and phosphorus are normal in blood tests. Whether the local calcium and phosphorus metabolism of the alveolar is abnormal due to viral infection, but the related virus has never been isolated from the lung tissue.
Chromosomal recessive inheritance (40%):
According to molecular genetics theory, biological traits are closely related to biological metabolism. Any metabolic process is a biochemical process. The genetic characteristics of a living organism depend on the order of nucleotides on the chromosomal DNA strand. A wide range of calcium and phosphorus corpuscles are deposited in the alveoli of this disease, which may be caused by the "out of control" of biochemical regulatory genes. If a minor error occurs in the genetic code or password, the mutated gene can be passed to the offspring through the parent of the close relative.
Congenital (10%):
The disease may also be caused by abnormalities in calcium and phosphorus metabolism in the congenital lung.
Pathogenesis
The disease mainly invades the lungs, microscopic examination: the lungs become hard, solid, and the weight increases, some up to 4000 grams, the lungs are not collapsed from the chest, sinking in the water, cutting the lungs, feeling the friction of sand Exposed to the diffuse distribution of fine sand stones, sand stones with more lungs at the bottom of the lungs, but 80% of the alveoli have such stones in the severe cases, microscopic examination: micro-calculus diameter 0.02 ~ 3mm, 30% ~ 80% The alveoli contain onion skin-like objects, most of which are densely calcified. The single stone has a circular concentric plate structure, stained with SE or PAS, and the central part is darkly dark. The main components of the stone are calcium phosphate and small amount. Calcium carbonate salt, there is a fibrous cord-like interstitial space between the stones, macrophage infiltration around the stone, no inflammatory reaction in the early stage, different degrees of leukocyte infiltration in the late stage, some can see different degrees of interstitial fibers Chemical.
Prevention
Alveolar microlithiasis prevention
To avoid or reduce dust, smoke inhalation, avoid active and passive smoking, so as not to aggravate lung damage, prevent and prompt treatment of colds, lower respiratory tract and lung infections, oxygen therapy should be given to family oxygen therapy to delay pulmonary hypertension and chronic The occurrence of pulmonary heart disease.
Complication
Alveolar microlithiasis complications Complications pulmonary hypertension respiratory failure
After several years, ten or decades later, it gradually developed into pulmonary hypertension, chronic pulmonary heart disease and respiratory failure.
Symptom
Symptoms of alveolar microlithiasis Common symptoms Breathing sounds low sputum purulent sputum dry cough sputum blood short dyspnea erythrocytosis respiratory failure chest tightness
The disease can occur at any age. It has been reported in the literature that it occurs from infants to children at the age of 90, but most of them occur in 20 to 30 years old. Women are reported abroad more than men, and women account for about 60%. In contrast, domestic reports: The female is 3:1. It has been reported that the disease has a certain regionality. The high incidence of the disease in Turkey is exemplified. The disease is chronic and progressive, and there is no symptom in the early stage. It is found during routine physical examination that mild dry cough and chest tightness may occur. Symptoms, generally do not pay attention, with the development of the disease, gradually appear chest tightness, shortness of breath, breathing difficulties after activities, increased cough, accompanied by a small amount of mucous sputum, hemoptysis is rare, late symptoms aggravated, breathing difficulties at rest, cyanosis Both are obvious, and secondary erythrocytosis can occur; such as secondary pulmonary infection, there are fever, coughing, purulent sputum, hemoptysis and other symptoms, early signs are often absent, as the disease progresses, the lung bottom breath sounds Low, bursting voice can occur, auscultation in the lungs can have voices after infection, after several years, ten or decades later, gradually developed into pulmonary hypertension, chronic pulmonary heart disease and respiratory failure.
Examine
Examination of alveolar microlithiasis
Microscopic stones can sometimes be seen in sputum or bronchoalveolar lavage fluid (BALF).
1. Imaging examination is the main means of diagnosing this disease. PAM has the following specific features on X-ray:
(1) Small nodules with diffuse distribution of the two lungs, diameter <1mm, high density, clear edges, but irregular shape.
(2) The density and distribution of nodules are prominent in the middle and lower lung fields, and the middle zone is prominent. When the lesions overlap, the ground glass or flaky shadows can be displayed.
(3) The lesions may not change significantly for many years, but may also increase slightly. A small number of patients cough stones and see fewer lesions.
(4) Later, it can cause different degrees of fibrosis, emphysema, and pulmonary bleb, which eventually lead to pulmonary hypertension and chronic pulmonary heart disease.
(5) can be spontaneous pneumothorax, radiology often divided into light, medium and heavy according to the extent and density of the lesion.
1 Mild: chest radiographs have a wide diffuse sand-like or star-like calcareous spots in the middle and lower lung fields. The boundaries between the spots are clear, the upper lung fields are clear, the fine texture of the calcareous fibers is upward, the external radiation, the hilar shadow Normal, diaphragm, rib angle, palpebral angle and outline of heart shadow are clearly identifiable. At this time, there are no clinical symptoms, and routine laboratory examination and pulmonary function examination are mostly normal.
2 moderate: from the second intercostal space, it is characterized by diffuse fine sand-like calcium spots, which are obvious in the inner and lower lung fields. The fine texture of calcium is radially from the hilum and upward, and the calcium points are not yet fused. The left and right heart margins have been partially covered. At this time, most of them have only mild clinical symptoms, and the lung function has ventilation function disorder, PaO2 is decreased, and P(Aa)O2 is increased.
3 Severe: The entire lung field is densely sand-like or star-like calcareous spots, especially in the middle and lower lung fields. The apical area is increased in transparency due to the relationship of vesicular emphysema. The fine texture of calcium is to the tip of the lung and around. Radiation, heart shape, rib angle, cross-sectional contour disappeared, even a blur, hilar lymph nodes were not swollen.
A small number of patients with X-ray films showed diffuse high-density lamella shadows and reticular changes, which need to be confirmed by chest CT. Chest CT and HRCT can clearly show miliary, high-density edge-clear micro-calculus shadows. It can be seen that the interlobular septal thickening, fibrosis and adjacent visceral involvement.
2. Pulmonary function test: Pulmonary function changes are also gradual, and there is no abnormality in early lung function. As the disease progresses, ventilatory dysfunction, diffuse dysfunction and hypoxemia may gradually appear, further worsening, and limitations occur. Ventilation dysfunction, advanced into respiratory failure.
Diagnosis
Diagnosis and diagnosis of alveolar microlithiasis
According to the history of the disease and the characteristics of imaging, the diagnosis of this disease is generally not difficult. Very few patients need sputum, bones obtained in BALF or confirmed by fiberoptic bronchoscopy lung biopsy.
Because some diseases have similar diffuse small nodules or miliary shadows on the X-ray, this disease needs to be diagnosed with the following diseases.
1. Miliary tuberculosis: symptoms of tuberculosis, such as high fever, fatigue, loss of appetite, weight loss, acute illness, X-ray chest radiographs in the acute phase of diffuse distribution of size, density, distribution of three uniform, marginally clear millet The shape of the shadow is much lower than that of the alveolar microlithiac; the subacute and chronic hematogenous disseminated pulmonary tuberculosis, the size of the two upper and middle lung fields, and the density of the lesions are very different from the alveolar microlithiasis.
2. Dust-sucking lung: The disease has a history of inhalation of silicon dust, the size of the X-ray nodules in the lungs varies, and the fibrous mesh-like shadows are included. The lesions are consistent with the bronchial direction, stage I silicosis, hilar lymph node enlargement; stage III silicosis, Conjunctival sacral nodules often appear in the upper part of both lungs.
3. Idiopathic pulmonary hemosiderosis: This disease is more common in children, with repeated hemoptysis, shortness of breath, fever and hypoxia and cyanosis. The lungs may have a lighter density and nodular shadows of different sizes. And flaky infiltration, after the hemoptysis stops, the shadow can be gradually absorbed, leaving a small amount of mesh, fibrous shadow.
