Desquamative interstitial pneumonia

Introduction to desquamative interstitial pneumonia Desquamative interstitialpneumonitis (DIP) is a type of interstitial pneumonia that is characterized by chronic lung inflammation characterized by airway mononuclear cell infiltration. DIP is a clinically and pathologically independent disease name that affects smokers between the ages of 30 and 40. Most patients have shortness of breath. It is characterized by extensive a large number of alveolar cell desquamation and hyperplasia in the alveolar cavity and a good response to steroid hormones. basic knowledge The proportion of illness: 0.003% Susceptible people: no specific population Mode of infection: non-infectious Complications: respiratory failure

The cause of desquamative interstitial pneumonia

Cause of the disease (50%)

The cause of desquamative interstitial pneumonia is unknown. It is a foreign body reaction or an autoimmune phenomenon or a sequelae of infection. It is unclear. Because rheumatoid factor, anti-nuclear antibody and lupus erythematosus cells have been found, it was once considered to be a kind of Connective tissue disease is also thought to be associated with alveolar proteinosis. It has also been reported to be secondary to respiratory viruses and mycoplasma infections, or without any obvious cause. It has been reported in children with inflammatory bowel disease treated with Sulfesalazine.

Pathology (30%)

Desquamative interstitial pneumonia is an interstitial pneumonia. The main histological features are as follows:

1 lung epithelial cells (mainly type II lung cells) proliferate and fall off into the alveolar space;

2 Macrophages accumulate in the alveoli and are positive for PAS staining. The cytoplasmic granules of anti-amylase are free in the alveolar space;

3 pulmonary interstitial lymphocytes, monocytes, plasma cells and eosinophils infiltration;

4 The alveolar wall is significantly thickened by edema, hyperemia and cell infiltration. Eosinophilic nucleus inclusions in type II lung cells and exfoliated cells are caused by degeneration, which is composed of myelin, no alveolar wall necrosis. And no transparent membrane formation, occasionally macrophages fuse to form multinucleated cells, so it is very similar to giant cells, so some people think that this disease is the early stage of giant cell interstitial pneumonia, the disease is not clear, but there are observations After several years, the disease can evolve into diffuse pulmonary fibrosis and even evolve into pulmonary heart disease.

Desquamative interstitial pneumonia prevention

1. Avoid cold and prevent upper respiratory tract infection.

2. Actively improve the air quality in the living environment; eat more fruits and drink more water. Eat high protein digestible or semi-liquid foods.

3. Smoking patients should quit smoking immediately and change bad habits. Conducive to the recovery of the disease.

4, desquamation of interstitial pneumonia is best to eat salty, greasy, hot and dry products. It is not advisable to eat sweet fruits such as apricots, peaches, oranges, and plums to avoid heat and oysters. Pepper, pepper, Sichuan pepper, mustard, etc. should not be added to the diet. No smoking ban.

Desquamative interstitial pneumonia Complications, respiratory failure, pneumothorax

Pulmonary infection is a common complication, can induce respiratory failure, and even lead to death, should be actively treated, hypoxemia is common, there may be no obvious incentives, such as PaO2 <7.33kPa (55mmHg), Home oxygen therapy should be performed. In the late stage of pulmonary heart disease with right heart failure, according to cardiac insufficiency treatment, pneumothorax may occur repeatedly for pleural adhesions.

Symptoms of desquamative interstitial pneumonia Common symptoms Difficulty breathing, loss of appetite, dry cough, pulmonary dyspnea, weight loss, heart failure, purpura edema

The disease can be divided into primary and secondary, the primary disease is more acute, secondary to other diseases, the symptoms are similar to diffuse pulmonary fibrosis, the incidence of more insidious, but also suddenly Disease, mainly manifested as rapid breathing, progressive dyspnea, heart rate increase, purpura, dry cough, weight loss, weakness and loss of appetite, fever no more than 38 ° C, severe heart failure, can suddenly die after eating milk, Physical examination sometimes shows clubbing, toe, lung signs are not obvious, sometimes the lower lung can hear the fine wet rales, X-ray chest shows two lungs glass or mesh, flaky shadow, can have edges The blurred triangular shadow of the Qing dynasty is released from the lung edge along the heart to the lung base and the periphery. Sometimes there are complications such as emphysema, pneumothorax and pleural effusion. In the long-term, pulmonary heart disease can be complicated, and peripheral blood eosinophils can be seen to increase.

X-ray performance, the two lungs have symmetrical frosted glass shadows, the most prominent at the bottom of the lungs, there are also triangular blurred shadows, stretching from the hilum to the lungs on both sides, sometimes with spontaneous pneumothorax or pleural effusion.

The diseased lungs are grayish yellow, solid, airless, and microscopically examined. The most prominent feature is that there are a large number of desquamated granular cells in the alveolar cavity, ranging in size from 7 to 8 m; some cells are spindle-shaped, multinucleated, and cells. It contains very few vacuoles, no carbon residue, cytoplasm containing a large amount of PAS staining positive, anti-amylase granules, often iron-free pigment granules, lipid staining positive, electron microscopy, most of desquamation cells are giant Phagocytosis, alveolar epithelial cells and desquamation cells see mitotic division, alveolar epithelial cells proliferate or hypertrophy, no transparent membrane formation, unequal amount of interstitial fibrosis and reticular fiber formation, sometimes showing the nature of myxoma, interstitial muscle fibers Hyperplasia, lung stiffness, common pulmonary lobular septa, alveolar septum and pleural edema and fibrosis, alveolar occlusion is not common, in the severe lung area, often occlusive pulmonary endarteritis, focal lymphocyte aggregation, which Germination Center.

Examination of desquamative interstitial pneumonia

Blood routine examination of red blood cells, hemoglobin increased, erythrocyte sedimentation rate, pulmonary function test DIP patients, lung function showed restrictive ventilation dysfunction, DLCO decreased, mild to moderate hypoxemia, P (A-aDO2) increased, early PaCO2 reduce.

X-ray chest radiographs have characteristic changes, about 75% of patients have very similar lung shadows, mainly as a triangular shadow, extending from the lung gate to the base of the two lungs along the heart, the bottom of the triangle is on the side, and the tip is at the corner of the heart. At the same time, the shadow is blurred and ground glass. The texture radiated from the lung door is obviously thickened. It is the dilated pulmonary vascular shadow, the shadow is thickened in the heart, and the peripheral edge of the lung is shallow and reduced. This typical shadow sometimes lasts 4 ~6 years unchanged, some change or gradually absorb within a few months, 25% of patients can show diffuse blurred spotted lung shadows, or in addition to the lung base triangle shadow, but also from the lung door The upper lung field is radioactively lined and smeared with blurred shadows. The whole lung field presents a "dirty-lung" appearance. 50% to 70% of the HRCT is ground glass, and there are also stoves. Sexual, flaky shadows, the main lesions are distributed in the lower lungs and middle lung fields, 50% to 60% have different degrees of fibrosis, but far less than IPF, there are few cell lungs, and some cases have subpleural pulmonary alveolar Easy to spontaneous pneumothorax, bronchoalveolar lavage Solution lymphocytes, alveolar macrophages, and plasma cells based inflammatory changes.

Diagnostic identification of desquamative interstitial pneumonia

diagnosis

From clinical symptoms, X-ray findings can only be diagnosed, and the diagnosis can be confirmed by bronchoscopy or open chest biopsy. The pathological diagnostic criteria proposed by Ashen et al. (1984) are as follows:

1 Macrophages containing PAS-positive granules were found to aggregate in the alveoli.

2 swelling and hyperplasia of type II epithelial cells in the alveoli.

There are lymphocytes in plasma, plasma cells and eosinophils infiltrating, and mild interstitial fibrosis.

Differential diagnosis

Idiopathic pulmonary fibrosis (pathologically known as interstitial pneumonia), respiratory bronchiolitis with interstitial lung disease, non-specific interstitial pneumonia, acute interstitial pneumonia, lymphocytic interstitial pneumonia And cryptogenic organizing pneumonia.

DIP is different in histopathological difference from interstitial pneumonia. The former tends to be diffuse and uniform, and may have alveolar septum due to fibrotic tissue, mild to moderately widened, with moderate lymphocytes, plasma. Cells and occasionally eosinophilic interstitial infiltration. The alveolar wall is lined with swollen cubic alveolar cells. The most prominent feature is that there are a large number of macrophages in most of the distal air cavities. There may be honeycomb-like changes, but usually not like It is as broad and obvious as in IUP. Some experts believe that distinguishing between DIP and UIP is artificial because both types of tissue often occur in the same lung (possibly representing different periods of the same disease). However, DIP-like responses in UIP are usually Very mild, and no similar lung parenchymal invasion was found in the DIP.

Pulmonary function tests showed a limited change with a decrease in DLCO, and arterial blood gas showed hypoxemia. Chest X-rays are normal in up to 20% of cases. If abnormal, the severity is lower than interstitial pulmonary fibrosis. HRCT shows patchy, subglacial ground-glass shadows.

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