Alveolitis is a diffuse inflammatory lesion of the alveolar and interstitial lung tissue that can occur in isolation or develop against other diseases.

Pulmonary alveoli participate in the act of breathing, providing gas exchange with pulmonary capillaries, and are the end part of the respiratory apparatus. The total number of alveoli reaches 600-700 million in both lungs..

Alveolitis is characterized by inflammation of the pulmonary alveoli Causes and risk factors Exogenous allergic alveolitis develops against the background of allergic reactions (often allergens are plant and house dust, drugs, pet hair, components of microscopic fungi, industrial irritants, etc.. The ingestion of an allergen causes the formation of IgG. Immune complexes (antigen-antibody) settle on the surface of the alveoli, which causes damage to the cell membrane, the release of a significant amount of biologically active substances with the development of the inflammatory process. An important role in the development of this form of alveolitis is played by repeated exposure of the allergen to the body..

Allergies to dust can lead to the development of allergic alveolitis. The causes of idiopathic fibrosing alveolitis are not fully understood.. It is assumed that the disease can be autoimmune in nature, occur against the background of infection with some viruses (hepatitis C virus, herpes virus, cytomegalovirus, adenoviruses). Risk factors for the development of this form of the disease include work in the agricultural sector, woodworking, metallurgy, and smoking. In this case, the inflammatory process in the pulmonary alveoli leads to an irreversible thickening of their walls, followed by a decrease in permeability for gas exchange.

The main reason for the development of toxic fibrosing alveolitis is a direct or indirect effect on the lungs of toxic substances that enter the pulmonary alveoli by the hematogenous or aerogenous route (among others, drugs such as Azathioprine, Mercaptopurine, Methotrexate, Furadonin, Cyclophosphamide).

Secondary alveolitis occurs against the background of other pathological processes. Most often it is sarcoidosis, tuberculosis, diffuse connective tissue diseases.

Risk factors include:.

genetic predisposition;

immunodeficiency states;

collagen metabolism disorders.

Forms of the disease Depending on the etiological factor, as well as the characteristics of the disease, there are:.

idiopathic fibrosing alveolitis;

toxic fibrosing alveolitis;

exogenous allergic alveolitis.

Lungs with fibrosing alveolitis Alveolitis can be primary and secondary, as well as acute, subacute and chronic.

Idiopathic fibrosing alveolitis is prone to gradual progression with the development of complications. Due to increasing irreversible changes in the alveolar-capillary system of the lungs, the risk of death is high.

Stages of the disease Depending on the histological picture, five stages of idiopathic fibrosing alveolitis are distinguished:.

Infiltration and thickening of the septum of the pulmonary alveoli.

II. Filling pulmonary alveoli with cell composition and exudate.

III. Destruction of pulmonary alveoli.

IV. Changing the structure of lung tissue.

The formation of cystic-altered cavities.

Symptoms of alveolitis Symptoms of alveolitis vary depending on the form of the disease, but there are a number of manifestations common to all forms of lung alveolitis. The main symptom is shortness of breath, which at the initial stage of the disease occurs after exercise, but as the pathological process progresses, it also begins to appear at rest. In addition, patients complain of dry, unproductive cough, fatigue, pain in muscles and joints. In the late stages of the disease, weight loss, cyanosis of the skin, as well as changes in the shape of fingers (“drumsticks”) and nails (“watch glasses”) are observed.

Dyspnea is the first symptom of alveolitis. The first symptoms of acute exogenous allergic alveolitis can appear within a few hours after contact with the allergen.. In this case, the general signs of the disease resemble the clinical picture of influenza. Patients have a fever, chills, headache, then cough and shortness of breath, heaviness and pain in the chest. In children with certain allergic diseases, asthma-like shortness of breath and sometimes asthma attacks occur in the initial stages of exogenous allergic alveolitis.. During auscultation, almost bubbly wet rales are heard over almost the entire surface of the lungs.. After the exclusion of contact with the allergen that caused the development of the disease, the symptoms disappear within a few days, but return with subsequent contact with the causative allergen. In this case, general weakness, as well as shortness of breath, which is aggravated by physical exertion, may persist in the patient for several weeks.

The chronic form of exogenous allergic alveolitis can occur with repeated episodes of acute or subacute alveolitis or independently. This form of the disease is manifested by inspiratory dyspnea, persistent cough, weight loss, deterioration of the general condition of the patient.

Complications of alveolitis can be chronic bronchitis, pulmonary hypertension, pulmonary heart, right ventricular heart failure, interstitial fibrosis, pulmonary emphysema, respiratory failure, pulmonary edema.

Idiopathic fibrosing alveolitis develops gradually, while the patient has irreversible changes in the pulmonary alveoli, which is expressed in increasing shortness of breath. In addition to severe shortness of breath, patients complain of pain under the shoulder blades that interfere with deep breath, fever. With the progression of the pathological process, hypoxemia increases (a decrease in the oxygen content in the blood), right ventricular failure, pulmonary hypertension. The terminal stage of the disease is characterized by severe signs of respiratory failure, an increase and expansion of the right heart (pulmonary heart).

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