Interstitial lung diseases are a group of diseases that occur with the development of diffuse inflammation of the stroma of the lungs, mainly bronchioles and alveoli. A reflection of such changes are fever, general malaise, weight loss, unproductive cough, dry inspiratory wheezing, pulmonary insufficiency (shortness of breath, tachypnea), right ventricular heart failure. The diagnosis of interstitial diseases is confirmed by the data of radiography and CT of the lungs, FER examination, lung biopsy. As a treatment, steroid therapy (or cytostatics), bronchodilators, and oxygen therapy are prescribed.
ICD 10
J84 Other interstitial lung diseases
Meaning
Interstitial lung diseases (ILD) are various lung lesions, the pathomorphological basis of which is chronic diffuse inflammatory infiltration of the alveoli, small bronchi, pulmonary capillaries with the outcome in fibrosis. ILD includes 130 diseases of clear and unclear etiology. In patients hospitalized in pulmonology departments, certain interstitial lung diseases are diagnosed in 10-15% of cases. The predominant contingent of patients are men aged 40-70 years, in most cases smokers. Some diseases of this group have a reversible course and a relatively favorable prognosis, while others lead to disability and even death early.
Classification
Currently, the classification of ILD, developed in 2002 by the American Thoracic Society (ATS) and the European Respiratory Society (ERS), has been adopted as a basis. According to this classification , interstitial lung diseases are distinguished:
1. With established etiology:
- medicinal, radiation, toxic ILD
- pneumomycosis associated with HIV infections
- ILD on the background of collagenoses (scleroderma, dermatomyositis, rheumatoid arthritis, SLE) and pneumoconioses (asbestos, silicosis, berylliosis)
- ILD on the background of infections (atypical pneumonia, disseminated pulmonary tuberculosis, pneumocystis pneumonia, etc.)
- ILD on the background of exogenous allergic alveolitis
2. Idiopathic interstitial pneumonia:
- nonspecific, desvamative, acute, lymphoid, cryptogenic organizing;
- idiopathic pulmonary fibrosis
3. Granulomatous:
- ILD on the background of sarcoidosis, Wegener’s granulomatosis, hemosiderosis of the lungs, exogenous allergic alveolitis
4. Associated with other diseases:
- pathology of the liver (chronic hepatitis, primary biliary cirrhosis of the liver), intestines (NYAK, Crohn’s disease), CRF
- hereditary diseases (neurofibromatosis)
- malignant tumors
5. Other:
- associated with histiocytosis X, lymphangioleiomyomatosis, pulmonary proteinosis, primary amyloidosis of the lungs.
The pathomorphological classification of interstitial lung diseases distinguishes the following types of interstitial fibrosis: simple, desquamative, lymphocytic, giant cell, and obliterating bronchiolitis with pneumonia.
Interstitial lung diseases causes
To date, the etiological mechanisms of most ILD remain unclear. We can only reliably talk about the causes of interstitial lung diseases with a known etiology. Among them – inhalation of inorganic substances, organic dust, mercury vapor; taking toxic drugs (cyclophosphamide, penicillamine, bleomycin, etc.), radiation therapy.
Recurrent bacterial, fungal and viral pneumonia, tuberculosis of the respiratory system, respiratory distress syndrome, bronchoalveolar cancer may underlie the development of ILD. In addition, interstitial lung diseases can accompany collagenoses, blood diseases (hemolytic anemia, thrombocytopenic purpura, chronic lymphocytic leukemia), hereditary diseases, etc. The most significant risk factor for ILD is smoking.
In the pathogenesis of interstitial lung diseases, acute, chronic and terminal stages are distinguished. In the acute stage, the lesion affects the pulmonary capillaries and the alveolar epithelium, intraalveolar edema develops. During this period, there may be complete reversibility of changes or their progression. With the transition of ILD into a chronic course, extensive lung damage (widespread fibrosis) is noted. In the terminal stage, the alveoli and capillary network are completely replaced by fibrous tissue with the formation of expanded cavities (a lung in the form of “honeycombs”).
Interstitial lung diseases symptoms
Despite the variety of etiological forms of ILD, their clinical course is largely similar and characterized by general and respiratory symptoms. Often the disease begins gradually, and the manifestations are vague, nonspecific in nature.
General symptoms may include fever, malaise and fatigue, weight loss. Signs of respiratory failure play a decisive role in the clinical picture of interstitial lung diseases. The earliest and most permanent symptom is shortness of breath: at first it occurs or increases only with exertion, then it becomes constant and progressive. Shortness of breath is usually inspiratory in nature and is accompanied by wheezing, which can be mistaken for bronchial asthma.
A characteristic symptom of ILD is an unproductive cough – dry or with scanty mucous sputum. Later signs of ILD include cyanosis and the formation of “Hippocratic fingers”. Chest deformities occur with great frequency. In severe forms, pulmonary heart failure develops.
In children, interstitial lung diseases occur with a constant cough, stridor, and are often accompanied by the formation of bronchiectasis. Persons over 70 years of age are extremely rarely ill, however, in older age, IHD is often accompanied by arrhythmias, myocardial infarction.
Diagnostics
When examining a patient with a pulmonologist, attention is drawn to tachypnea, the discrepancy between the severity of shortness of breath and physical changes in the lungs. During auscultation, crepitating wheezes of various localization are heard on inspiration. In the blood – moderate leukocytosis and increased ESR; according to ELISA – negative serological tests for the presence of At to mycoplasma, legionella, rickettsia. The analysis of the gas composition of blood and CSF is carried out (arterial hypoxemia in the early stages is replaced by hypercapnia in the terminal stage).
Radiological methods (radiography and CT of the lungs) are of great informational value in the diagnosis of interstitial lung diseases. In the early stages, on X-ray and tomograms, one can see deformation and strengthening of the pulmonary pattern, fine-focal shadows, a decrease in the transparency of the pulmonary fields (the phenomenon of “frosted glass”); in the future, an X-ray picture of interstitial fibrosis and a picture of a “cellular lung” develops.
According to spirometry data, a restrictive type of pulmonary ventilation disorders, a decrease in pulmonary volumes is more often detected. With the development of pulmonary hypertension, ECG shows myocardial hypertrophy of the right parts of the heart. Diagnostic bronchoscopy allows for bronchoalveolar lavage; with ILD, neutrophils predominate in the flushing waters of the bronchi. In addition, a trans-bronchial lung biopsy can be performed during an endoscopic examination. Also, in some cases, open or transthoracic lung tissue biopsy is resorted to.
Treatment for interstitial lung diseases
The first step in the treatment of ILD should be quitting smoking, interaction with harmful production factors, toxic drugs. All subsequent therapy is carried out in parallel with the treatment of the underlying disease.
In most cases, first-line drugs for interstitial lung diseases are corticosteroids (prednisone), which are prescribed in high dosages for 1-3 months, followed by a transition to a maintenance dose. In the absence of positive dynamics during the year, cytostatics (cyclophosphamide, azathioprine, chlorambucil) are prescribed. From other pharmaceuticals, bronchodilators are used (inside and in the form of inhalations), but they are effective only at the stage of reversible bronchial obstruction. With arterial hypoxemia (RaO2 <50-55 mmHg), oxygen therapy is indicated. In the case of severe interstitial lung disease, lung transplantation may be the only effective method.
The outcomes of IHD can be improvement, stabilization of the condition, progression of pulmonary fibrosis, death, less often – spontaneous regression of changes (for example, in nonspecific interstitial pneumonia). The average life expectancy of patients ranges from 1 year in Hamman-Rich disease to 10 years or more in respiratory bronchiolitis. Prevention of interstitial lung diseases is possible only in the case of a known etiology.