PAS staining positive

Introduction Pulmonary alveolar proteinosis (PAP), also known as Rosen-Castle-man-Liebow syndrome. The alveolar and bronchial lumens are filled with PAS staining positive, and the phospholipid-rich protein material from the lung is characterized. It occurs in young and middle-aged people, and the incidence of men is about three times that of women. The cause is unknown and may be related to immune dysfunction (such as thymus atrophy, immune deficiency, lymphopenia, etc.). Dust, especially those exposed to dust, can cause PAP, so it is thought that it may be a non-specific reaction to certain irritants, leading to decomposition of alveolar macrophages and production of PAS-positive proteins.

Cause

The cause is unknown, and it is speculated to be related to several factors: such as a large amount of dust inhalation (aluminum, silica, etc.), decreased immune function (especially infants and young children), genetic factors, alcoholism, microbial infections, etc. For infections, it is sometimes difficult to confirm whether it is a primary pathogenic factor or secondary to alveolar proteinosis. For example, cytomegalovirus, Pneumocystis carinii, histoplasmosis infection, etc. are found to have high protein deposition in the alveoli.

Although the triggering factor is not clear, it basically agrees that the pathogenesis is caused by lipid metabolism disorder. That is, the metabolism of alveolar surfactant is abnormal due to the action of internal and external factors. So far, more studies have shown the activity of alveolar macrophages. Animal experiments have shown that the activity of macrophages after phagocytosis of dust is significantly reduced, and the particles in macrophages in the lavage of patients can reduce the viability of normal cells. After alveolar lavage treatment, the alveolar macrophage activity can be increased. The study did not find an increase in type II cell-producing proteins, and no abnormalities in systemic lipid metabolism. Therefore, it is generally believed that this disease is associated with a decline in clearance capacity.

an examination

Related inspection

Chest radiography bronchoscopy

Pathological diagnosis is mainly based on bronchoalveolar lavage examination or fiberoptic bronchoscopy or thoracotomy. The coughed sputum was fixed with 80% ethanol, and PAS stained with 15% positive lipid.

Diagnose based on:

A small number of cases can be asymptomatic, with only X-ray abnormalities. Respiratory dysfunction is aggravated with the development of the disease, and breathing difficulties accompanied by cyanosis also become more serious.

Differential diagnosis

Alveolar proteinosis is non-specific and should be differentiated from:

1 idiopathic pulmonary interstitial fibrosis: idiopathic pulmonary interstitial fibrosis (respiratory medicine) (IPF) refers to diffuse inflammatory disease of the lower respiratory tract of unknown cause. Inflammation invades the alveolar wall and adjacent alveolar spaces, causing alveolar septal thickening and pulmonary fibrosis. Alveolar epithelial cells and capillary endothelial cells, which can also be involved in small airways and small blood vessels. Its clinical features include progressive dyspnea, Velcro, and progressive hypoxemia. Impaired lung function is dominated by restrictive ventilatory disorders and diffuse dysfunction.

2 alveolar carcinoma: alveolar cell carcinoma: originated from the bronchial mucosa epithelium, also known as bronchioloalveolar cell carcinoma or bronchioloalveolar carcinoma, or abbreviated alveolar carcinoma. The part is around the lung field. In all types of lung cancer, the incidence is low, and women are more common. Generally, the degree of differentiation is higher and the growth is slower. The cancer cells grow along the bronchioles, alveolar ducts and alveolar walls without invading the alveolar septum. Lymphatic and hematogenous metastases occur later, but can spread to other lungs or invade the pleura via the bronchus. Alveolar cell carcinoma has two types of nodular and diffuse types in X-ray morphology. The former can be a single nodule or multiple nodules; the latter is similar to pneumonia.

3 Miliary tuberculosis: Tuberculosis is a chronic infectious disease caused by Mycobacterium tuberculosis. Mainly transmitted through the respiratory tract. All organs of the body can occur, but tuberculosis is the most common. Its pathological features are tuberculous nodules with varying degrees of caseous necrosis.

4 lung substantive diseases such as viral pneumonia, mycoplasma pneumonia and chlamydia pneumonia. Pathological diagnosis is mainly based on bronchoalveolar lavage examination or fiberoptic bronchoscopy or thoracotomy. The coughed sputum was fixed with 80% ethanol, and PAS stained with 15% positive lipid.

Diagnostic basis: a small number of cases can be asymptomatic, only X-ray has abnormal performance. Respiratory dysfunction is aggravated with the development of the disease, and breathing difficulties accompanied by cyanosis also become more serious.

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