Pediatric alveolar proteinosis

Introduction to pulmonary alveolar proteinosis in children Pulmonary alveolar proteinosis (PAP) is a subacute, progressive respiratory dysfunction. The accumulation of mucinous substances and lipids in the alveoli, also known as pulmonary alveolar phospholipidosis, is an unknown cause. The rare chronic lung disease is characterized by the accumulation of lipid-rich glycogen (PAS)-positive protein substances in the alveoli. These substances are called surface active substances and are a mixture of phospholipids and various surface active proteins. Due to the accumulation of excess surface active substances in the alveolar cavity and airway, the ventilation and ventilation functions of the lungs are severely affected, resulting in difficulty in breathing. Dyspnea is the most prominent clinical manifestation of alveolar proteinosis. There are two types of PAP in childhood: lethal congenital PAP and acquired acquired PAP. basic knowledge The proportion of illness: the incidence rate is about 0.005% - 0.0075% Susceptible people: infants and young children Mode of infection: non-infectious Complications: respiratory failure

Causes of pulmonary alveolar proteinosis in children

(1) Causes of the disease

The cause is unknown. Some people think that this disease is a non-specific allergic reaction to inhaled chemical irritants; it is thought to be related to the body's immune deficiency; this disease is often accompanied by various fungal and bacterial infections; this disease can be seen familial, prompt It is related to hereditary factors; it is considered that this disease is similar to desquamative interstitial pneumonia, and may be different changes of the same disease, but desquamative interstitial pneumonia is effective with corticosteroid treatment, but this disease is ineffective, a small part of congenital PAP is associated with the lack of surfactant protein B. It has been reported that the subunit of granulocyte-macrophage colony stimulating factor (GM-CSF) receptor in 4 PAP infants. Defects in expression, SP-A, B and C in the alveolar lavage fluid of older children, but the structure of these proteins has a significant change, which changes the function and metabolism of alveolar surfactant.

(two) pathogenesis

Possible pathogenesis is:

1. Excessive production of normal or abnormal alveolar material (including phospholipids and lamellar bodies).

2. Alveolar abnormalities in the clearance of phospholipid proteins.

3. Unbalanced production and clearance of alveolar phosphatidic acid.

4. The ability of alveolar macrophages to break down lamellar bodies is impaired.

5. Hyperplasia and destruction of alveolar type II cells, the increase of immunoglobulin in bronchoalveolar lavage fluid of patients, alveolar sedimentation is formed by the reaction of infection or environmental toxic substances, animal experiments suggest: alveolar protein deposition and II Excessive secretion of surfactants in alveolar epithelial cells and alveolar macrophages are associated with decreased clearance of lipoprotein-like substances, and some patients with thymic lymphaplasia or immunoglobulin deficiency, often accompanied by various fungi and bacteria Infection; related to genetic factors; some congenital PAP is associated with the lack of surfactant protein B.

Prevention of pulmonary alveolar proteinosis in children

Pay attention to the prevention of recurrent infections, for unknown reasons, especially congenital PAP, no specific prevention methods.

Complications of pulmonary alveolar proteinosis in children Complications, respiratory failure

Mainly for respiratory failure and infection. Respiratory failure is a serious disorder of lung ventilation and/or ventilation function caused by various reasons, so that effective gas exchange cannot be performed, resulting in hypoxia with or without carbon dioxide retention, resulting in a series of physiological functions and metabolic disorders. Clinical syndrome.

Symptoms of pulmonary alveolar proteinosis in children Common symptoms Secondary infection Chest pain Breathing difficulty Pleural friction Fatigue Loss of appetite Hair loss Weight loss Arpeggio hemoptysis

Onset can be urgent and slow, and exercise intolerance is the most common first-time performance. If not diagnosed, it can be characterized as progressive dyspnea and cough, accompanied by fever, weakness, weight loss, chest pain, hemoptysis and loss of appetite. Infants and young children with respiratory symptoms are more insidious, mostly manifested as poor growth and development, can vomiting and diarrhea as the first symptoms, secondary infection can be yellow purulent, lesion progression can occur cyanosis and severe shortness of breath, signs are rare, only a little scattered in wet Arpeggio or pleural friction, sometimes visible to the clubbing, toe.

Examination of pulmonary alveolar proteinosis in children

an examination

Sputum check

The sputum specimens were fixed first, and hematoxylin and eosin were stained with PAS. The PAS-positive protein granules contained coniferous crystal stratified bodies, but the sputum sputum was often swallowed into the digestive tract and could not be collected. The liquid is contaminated by oral secretions, mixed with desquamated cells and other proteins, so the diagnostic value is not large. Some people use the thick sputum block discharged after lung lavage, add 0.1 equivalent of sodium hydroxide, and shake it, that is, see it. The upper layer turns pink, and according to the spectrum analysis, the spectrum of phenolsulfonium is the same as that of phenolsulfonate, and the phenolsulfonium has a great affinity with protein in an acidic environment.

2. Blood test

In the absence of liver lesions, serum lactate dehydrogenase (LDH) is often elevated, and when it returns to health, LDH is converted to normal, blood routine examination, lymphocyte reduction in about half of cases, serum IgA decreased.

Auxiliary inspection

1. X-ray manifestations: typical X-ray films can be seen around the hilar to see a small diffuse feathery infiltration shadow, spreading from the hilar to the lung edge, butterfly-like, slightly like pulmonary edema; or as a soft low density Nodular shadows, distributed in the shape of a butterfly, sometimes the inferior lobe of the lungs shows invasive lesions, or some patients begin to have nodular density deepening, starting to separate the phases, progressing from the inferior lobe to the entire lobules Consolidation, there is compensatory emphysema between the lesions or the formation of a small translucent area, the mediastinum is significantly widened, X-ray is like pulmonary edema, but no KB line.

2. Chest CT examination: especially high-resolution CT has great diagnostic value for PAP. The lung tissue of the lesion often has a ground-glass-like change, and the pleural thickening between the leaves and leaves is irregular.

3. Pulmonary function test: showed restrictive ventilation dysfunction, decreased lung capacity, diffuse dysfunction, arterial blood gas showed decreased oxygen saturation and chronic alkalosis.

4. Bronchoalveolar lavage fluid (BALF) examination: typical alveolar lavage fluid is milky or thick yellow liquid. Under light microscope, there are a lot of irregularities in the inflammatory cells, and eosinophilic granular lipoproteins of different sizes. The sample was positive for PAS staining. Under the electron microscope, there were a large number of cell debris of different sizes in the alveolar filling, surfactant particles and other protein-like substances. These surface active particles were visible under the microscope under 30,000 times. A layered structure of concentric circles.

Diagnosis and differential diagnosis of pulmonary alveolar proteinosis in children

diagnosis

Diagnosis of bronchoscopy for lung biopsy and pathological examination, clinical symptoms, chest X-ray and laboratory tests, sometimes also help to confirm the diagnosis, BALF examination combined with medical history and clinical manifestations, chest X-ray, can diagnose most patients with PAP .

Differential diagnosis

Congenital PAP develops symptoms early in the neonatal period and quickly leads to respiratory failure. Clinical and X-ray findings are not easily distinguished from other neonatal lung and heart diseases: neonatal pneumonia, systemic bacterial infection, persistent pulmonary hypertension, Meconium inhalation, infantile respiratory distress syndrome, alveolar capillary dysplasia, and congenital heart disease, especially pulmonary venous venous drainage, should be noted in addition to pulmonary edema, pulmonary fibrosis, sarcoidosis, pulmonary hemosiderosis Pulmonary mycosis and Cysticercus cellulosae, most patients with PAP have elevated serum surface active protein, but also mildly elevated in patients with idiopathic pulmonary fibrosis, pneumonia, tuberculosis, and bronchiolitis.

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