Interstitial lung disease and what you need to know

Interstitial lung diseases is a term that refers to a very large group (>200) of diseases that cause interstitial lung lesions. These diseases cause inflammation and scarring in the lungs. Interstitial lung disease often accompanies or leads to other comorbidities, and mortality from the disease is also common.

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• 1. General overview Interstitial lung disease
• 2. Causes of interstitial lung disease
• 3. Symptoms of interstitial lung disease
• 4. Tests
• 5. Diagnosis 
• 6. General treatment

1. General overview Interstitial lung disease

Interstitial lung disease is a group of diseases that cause diffuse lung parenchymal lesions due to different mechanisms, the degree of spread and scarring are also different.

Interstitial lung disease affects mainly the areas of the lung located between the alveoli and capillaries.

In terms of lung structure, the lungs are shaped like a trunk, with the bronchi as branches and the alveoli as leaves. Leaves will have leaf veins that are pulmonary capillaries to join with alveoli to absorb O2 and remove CO2.

Microscopic structures of alveoli and capillaries

Damage to the interstitial tissue makes the space between the leaves (alveoli) and veins (pulmonary capillaries) thicker, scarred, limiting the body's gas exchange. In addition, it also increases the distance between the alveoli, causing a number of other effects.

Microscopic image of normal lung (left) and fibrosis lung (right)

However, it must be affirmed that interstitial lung disease is sometimes referred to as Diffuse parenchymal lung disease. In which the lung parenchyma also includes: alveoli (leaves) and bronchi (branches).

2. Causes of interstitial lung disease

According to the American Thoracic Society (ATS) and the European Respiratory Society in 2001, a classification of interstitial lung disease was released. This classification is mainly based on 2 groups: Known causes and unknown causes. 

2.1 Known causes of interstitial lung disease

2.1.1 Due to metal inhalation: (on long-term exposure)

• Abestos (also known as Asbestos): Is a substance present in building materials today.

Photograph of a worker taking Asbestos from the metal

• Silica: In the window, glass jar. Patients exposed to glass manufacturing.
• Hard metals: Cobalt, tungsten. Common in workers participating in production without wearing masks.
• Coal dust: Common in people exposed to a lot of time such as coal miners, people who cook with firewood and coal regularly.

2.1.2 Use of drugs 

• Nitrofurantoin: Antibiotics, treatment of urinary tract infections.
• Amiodarone: A drug used to treat cardiac arrhythmias.
• Methotrexate: Immunosuppressive drug, treatment of ectopic pregnancy, cancer.
• Chemotherapy: Chemotherapy drugs.

2.1.3 Contact with organic matter:

• Feathers: usually parrots. Can be seen in patients who like to keep pets.
• Hay.
• Mold.
• Atypical bacteria (most notably tuberculosis).

2.1.4 Other interstitial disease effects

• Rheumatoid arthritis .
• Polymyositis/dermatomyositis.
• Scleroderma (scleroderma).
• Sjogren 's syndrome .
• Smoking cigarettes, including e-cigarettes.

2.2 Cause unknown

Based on the patient's examination, examination and imaging such as CT scan, lung X-ray, biopsy, the doctor can also make a number of distinctions, such as based on the progression of the disease: 

Fast (grant – within 1 week):

• Cryptogenic organizing pneumonia.
• Acute eosinophilic pneumonia (Acute eosinophilic pneumonia).
• Diffuse alveolar hemorrhage.
• Acute hypersensitivity pneumonitis.
• Acute interstitial pneumonia.
• Exacerbations of primary pulmonary fibrosis and of other interstitial lung conditions.

Slowly (semi-grade/chronic):

• Connective tissue disease.
• Primary pulmonary fibrosis.
• Sarcoidosis granuloma.
• Chronic hypersensitivity pneumonitis.
• Occupational lung disease (inorganic exposure).
• Nonspecific interstitial pneumonia.
• Desquamative interstitial pneumonitis.
• Interstitial lung disease (respiratory bronchiolitis interstitial lung disease).
• Lymphocytic interstitial pneumonia.
• Chronic eosinophilic pneumonia.

3. Symptoms of interstitial lung disease

Symptoms of this group of diseases are not specific. Usually, interstitial lung disease will have symptoms for a long time, gradually increasing until the patient comes to the doctor.

3.1 Main symptoms of interstitial lung disease

• Shortness of breath on exertion.
• Dry cough.
• Abnormal chest X-ray.

3.2 Distinguishing symptoms 

Acute symptoms that need to be distinguished from other diseases:

• Lung infection.
• Acute heart failure (acute pulmonary edema).
• ARDS (Adult acute respiratory distress syndrome).

Chest X-ray is the imaging test of choice in patients with respiratory abnormalities. 

If symptoms are chronic, then usually a trial of antibiotics (when the doctor suspects pneumonia) and diuretics (if heart failure is suspected).

4. Tests

• Chest X-ray is the first laboratory imaging test to suggest the diagnosis of interstitial lung disease

• High-resolution CT scan of the lung (each cut <1.5mm apart)="">is a test to help evaluate lung lesions

• Blood tests

• Other (lung biopsy, endoscopy – bronchoalveolar lavage)

5. Diagnosis 

As listed, it is relatively difficult to diagnose and find the cause. The multifaceted combination of medical examination and examination, chest X-ray, lung CT scan, blood test, lung biopsy is essential. In about 30% of cases, even a biopsy of lung tissue is not very effective to diagnose the disease. Therefore, to make a diagnosis, the doctor must have a combination of all aspects:

• Examination.
• Ask illness.
• X-ray of the lungs.
• CT scan of the chest.
• Lung biopsy.
• Blood tests.

6. General treatment

Depending on the cause of the disease, there are different treatment options. But, all patients need:

6.1 Quit smoking

The risk of developing lung cancer is increased if it is accompanied by smoking. This risk is 200 times higher (for subjects who smoke 1 pack/day) than in non-smokers. Surprisingly, this group of people had a better chance of survival later on than non-smokers. This could be explained that smoking causes chronic obstructive pulmonary disease (COPD) , so that the manifestation of interstitial lung disease appears from the onset of the disease.

6.2 Rehabilitation of respiratory function

Breathing exercises to restore respiratory function

6.2.1 Endurance training

Usually 3 to 5 times per week, training continuously for 20 to 60 minutes each time. For example, jogging or cycling.

6.2.2 Alternate practice

This is a type of endurance exercise with rest periods. It consists of extreme physical activity interspersed with gentle bursts of exercise. Or take a break. For example, cycle at peak strength for 30 seconds, then rest or pedal lightly for 30 seconds, repeating several times.

6.2.3 Strength training

Is a case of heavy weightlifting to develop muscle strength in the arms and legs. This program targets the muscles used in daily activities. For example, getting dressed, showering, shopping, and housework to make it easier for you.

6.2.4 Electroneuromuscular stimulation

If you are severely damaged with shortness of breath or heart disease, you may be encouraged to do neuromuscular electrical stimulation. This type of exercise uses electrical impulses to strengthen the muscles in the legs to develop strength and workability.

6.2.5 Inspiratory muscle training

Do exercises to strengthen the respiratory muscles, to develop muscle strength and work ability

Interstitial lung disease is a syndrome caused by hundreds of diseases. If detected and treated early, the quality of life and disease complications will be low. Smoking is currently one of the leading causes of lung disease in Vietnam. This includes interstitial lung disease, chronic obstructive pulmonary disease (COPD) and lung cancer . Quitting smoking is protecting both yourself and your family.

Doctor Nguyen Doan Trong Nhan