pneumoconiosis



Overview of the disease

Long-term inhalation of dust and retention in the lungs, resulting in diffuse fibrosis of lung tissue is mainly a group of lung diseases early on, mostly asymptomatic or asymptomatic, with the progression of the disease cough, sputum, chest pain, chest tightness and other symptoms in the occupational activities of the long-term inhalation of productive mineral dust and the cause of the disease no specific treatment, the main treatment methods include general treatment, drug treatment, surgical treatment, etc.

Definition

Pneumoconiosis (hereinafter referred to as pneumoconiosis) is a collective term for a group of occupational lung diseases caused by long-term inhalation of productive mineral dusts of different pathogenicity in occupational activities and deposition of such dusts in the lungs, resulting in diffuse fibrosis of lung tissues.

Pneumoconiosis is the most serious and common occupational disease in China.

Classification

According to the type of long-term inhalation of productive mineral dust, pneumoconiosis can be classified into various types, mainly including silicosis (silicosis), coal workers’ pneumoconiosis, asbestosis, graphite pneumoconiosis, carbon black pneumoconiosis, talcum pneumoconiosis, cement pneumoconiosis, mica pneumoconiosis, potter’s pneumoconiosis, aluminum pneumoconiosis, welder’s pneumoconiosis, and casting pneumoconiosis.

Morbidity situation

As of 2017, China has cumulatively reported more than 950,000 cases of occupational diseases, including more than 850,000 cases of pneumoconiosis, accounting for 89.8%, mainly silicosis and coal workers’ pneumoconiosis. Silicosis is also the most serious of the pneumoconiosis.

According to information published in Global Burden of Disease (2015), the estimated number of pneumoconiosis cases that died in China in 2015 was 9,538, and silicosis cases were 6,456.

Causes of the disease

Causes of the disease

The main cause of pneumoconiosis is the long-term inhalation of productive mineral dusts of different pathogenicity during occupational activities, which are retained in the lungs and cause diffuse fibrotic changes in the lung tissue. Different kinds of productive mineral dusts can cause different kinds of pneumoconiosis, which are as follows.

Silicosis: caused by long-term inhalation of dust containing free silica crystals.

Coal workers’ pneumoconiosis: caused by long-term inhalation of coal mine dust (silica dust and coal dust particles) in the production environment by coal miners.

Asbestosis: caused by long-term inhalation of large amounts of asbestos fibers.

Hard metal pneumoconiosis: caused by exposure to dust from hard metal objects (e.g. dust from handling cobalt).

Caster’s pneumoconiosis: caused by long-term inhalation of mixed dusts such as clay, graphite, coal dust, limestone and talcum powder, which contain very low silica.

Predisposing factors

Prolonged exposure to environments with productive mineral dust and failure to wear dust masks or helmets under dust exposure.

Involved in operations such as rock rolling, crushing, glass manufacturing, crushing, asbestos screening and asbestos processing.

Engaged in rock drilling and blasting in mining, quarrying, and tunneling.

Engaged in sand grinding, sand mixing, molding, furnace laying, sand blasting and sand cleaning in the foundry industry.

Have chronic lung diseases such as emphysema and tuberculosis.

Symptoms

Main Symptoms

Pneumoconiosis has a long course, and early symptoms may be asymptomatic or inconspicuous and often neglected by patients. As the disease progresses, the symptoms gradually worsen (the disease will still progress and worsen even if the patient is out of the dust-exposed environment), and the main manifestations are as follows.

Cough and sputum

The degree of coughing and the amount of sputum are closely related to bronchitis or secondary infection in the lungs.

A few patients may have blood in sputum or hemoptysis.

Chest pain

Chest pain is often pins and needles.

It mostly occurs on one or both sides of the anterior chest.

Chest tightness and shortness of breath

If the lesion is extensive and progresses rapidly, the symptoms of chest tightness and shortness of breath (labored breathing or insufficient breath) are obvious and gradually worsen to dyspnea.

It may be accompanied by dizziness, generalized weakness, palpitations, emaciation, and susceptibility to lung infections.

Complications

Pneumothorax

Pneumothorax is mostly caused by rupture of alveoli due to severe coughing, aggravation of shortness of breath, extraction of heavy objects and other factors.

Most of the patients have an acute onset of the disease, which is characterized by sudden pinprick-like chest pain of short duration, accompanied by chest tightness and dyspnea, and may be accompanied by irritating cough.

Chronic Obstructive Pulmonary Disease (COPD)

Chronic obstructive pulmonary disease (COPD) is caused by chronic inflammation of the airways during prolonged dust exposure, resulting in irreversible airflow limitation.

Initially there is shortness of breath only during labor, walking up stairs or climbing, which is relieved by rest. As the lesion progresses, shortness of breath can also occur during level ground activities.

In the early stage, there will be varying degrees of hypoxemia, with labored breathing, chest tightness, and bruising of the lips and nail beds.

In severe cases, symptoms of respiratory failure may occur, such as cyanosis (cyanosis of the skin and mucous membranes, most commonly seen on the lips and tip of the nose), headache, drowsiness, and trance.

Chronic Pulmonary Heart Disease

Chronic pulmonary heart disease, also known as chronic pulmonary heart disease, is due to pneumoconiosis interstitial fibrosis caused by increased pulmonary resistance to pulmonary arterial hypertension, which in turn causes right ventricular hypertrophy, enlargement, and even the occurrence of right heart failure.

Severe dyspnea, increased respiratory rate, sedentary breathing, oliguria, double lower limbs or generalized edema may occur.

Consultation

Department of Medicine

Respiratory Medicine

Coughing, coughing up sputum, chest pain, chest tightness and other symptoms, it is recommended to consult a doctor promptly.

Emergency Department

For emergencies such as rapidly worsening respiratory distress, hemoptysis, or unconsciousness, immediate consultation at the Emergency Department is recommended.

Preparation for medical treatment

Preparing for medical treatment: registration, preparation of documents, common problems

Tips for medical treatment

Chest X-rays or chest CT are often needed, so avoid wearing clothes made of metal, and inform your doctor if you are pregnant or planning to become pregnant.

Preparation Checklist

Symptom list

Pay particular attention to the time of onset of symptoms, special signs and symptoms, etc.

Is there a cough? How long has the cough lasted?

Is there sputum? What kind of phlegm?

Is there chest pain or tightness? How long have the symptoms been present?

Under what circumstances do these symptoms worsen or lessen?

List of medical history

What kind of work was performed? Has there been prolonged exposure to mineral dust?

Are there regular physical examinations?

Checklist

Examination results of the last six months, which can be brought to the doctor’s office

Laboratory tests: blood test with C-reactive protein, arterial blood gas analysis, sputum examination

Imaging: Chest X-ray, Chest CT

Others: Lung function test

Medication List

Medications used in the last 3 months, if available, bring the box or package with you to the doctor’s office.

Anti-inflammatory drugs: budesonide aerosol, methylprednisolone, montelukast, zalustat

Bronchodilators: salbutamol, terbutaline, aminophylline, ipratropium bromide

Cough suppressants: codeine, dextromethorphan

Expectorants: Bromhexine, Ambroxol

Diagnosis

Diagnostic basis

Pneumoconiosis is an occupational disease and must be diagnosed by a doctor qualified in occupational diseases.

Medical history

A clear history of exposure to productive mineral dust.

Clinical manifestations

Symptoms such as cough, sputum, chest pain, chest tightness, exertional dyspnea, etc., which are gradually aggravated and recurring, may occur.

In severe cases, there may be signs of pulmonary insufficiency such as dyspnea, with corresponding signs of compensatory emphysema or emphysema in both lower lungs.

Laboratory tests

Laboratory tests are useful in determining the nature and extent of lung disease, but there are no laboratory tests that can be used to diagnose pneumoconiosis. They are usually used to rule out other diseases and to see if there are any comorbidities or complications.

Blood Tests

Routine blood tests: Elevated white blood cell and neutrophil counts may be seen in cases of exacerbation such as co-infections. Fasting is not required before the test.

Arterial blood gas analysis: It can understand whether the patient has hypoxia and the degree of hypoxia, and determine whether there is respiratory failure, acid-base balance disorder and other conditions.

Erythrocyte Sedimentation Rate (ESR): it is often increased when combined with specific and non-specific infections.

C-reactive protein (CRP): elevation is often seen in non-specific inflammation.

Sputum Pathogenesis

Helps to confirm the diagnosis of respiratory and lung infections, as well as to clarify the nature of the infection (bacterial, viral, mycoplasma, etc.). Also performs drug sensitivity tests, which are important in guiding treatment.

Mouth should be rinsed 3 times before the examination to keep the mouth clean.

Imaging

X-ray chest radiograph

It is the main diagnostic basis for pneumoconiosis.

The characteristic change of X-ray chest film of pneumoconiosis is the appearance of round or irregular small shadows on chest film. With the progress of the disease, the small shadows can gradually change from few to many, and the density of small shadows gradually increases, and then small shadows can be aggregated or large shadows can be formed.

The aggregation of small shadows or large shadows usually occurs in the upper part of the lung field, and the typical cases can be symmetrical bilaterally.

Precautions: Avoid wearing metal jewelry or clothing with metal buttons during the examination.

Chest CT

Compared with X-ray chest radiography, chest CT is more sensitive and helps in the differential diagnosis of the disease.

It is more likely to detect large shadows located behind the heart and mediastinum, in the spine or along the mediastinum, as well as small fused shadows at the tip of the lungs or behind the clavicle.

It has obvious advantages in the detection of emphysema, pulmonary pustules, pleural plaques, and the detection of cavities and calcifications within large shadows.

High-resolution CT (HRCT) improves diagnostic sensitivity and significantly reduces inter-reader variability compared to conventional X-ray chest radiographs.

Lung function tests

It is mainly used to understand the respiratory function and to clarify the presence of pulmonary dysfunction and its degree and type.

In early stage patients, lung function impairment is not obvious. With the progression of the disease, restrictive ventilatory dysfunction may appear.

When combined with bronchial lesions, there may be obstructive ventilation dysfunction or mixed ventilation dysfunction.

Precautions: Relax during the examination, and follow the doctor’s instructions for exhalation and inhalation.

Lung Biopsy

Lung biopsy to obtain a histopathologic diagnosis is used only when a clinical diagnosis cannot be established, e.g., inadequate history of occupational exposure, imaging studies suggesting malignancy or infection.

Staging

The diagnosis of pneumoconiosis is categorized into stage 1, 2 and 3 based on the overall density of small shadows on X-ray chest radiographs, the extent of their distribution, the presence or absence of clustering of small shadows, large shadows, pleural plaques, and so on.

Stage 1 Pneumoconiosis

Those who have one of the following manifestations

There are small shadows with an overall density of grade 1, distributed to at least 2 lung regions.

Exposure to asbestos dust with small shadows of overall denseness grade 1, distributed to only 1 lung area, along with pleural plaques.

Exposure to asbestos dust with small shadows of overall intensity 0, but with small shadows of intensity 0/1 in at least 2 lung areas, together with pleural plaques.

Pneumoconiosis stage 2

Those with one of the following manifestations.

There are small shadows of grade 2 overall intensity distributed over more than 4 lung regions.

There are small shadows of overall denseness grade 3 with a distribution of up to 4 lung areas.

Exposure to asbestos dust with small shadows of overall intensity grade 1 spreading over more than 4 lung areas, together with pleural plaques with partial involvement of the cardiac margins or diaphragmatic surfaces.

Exposure to asbestos dust with small shadows of overall intensity grade 2 spread over 4 lung areas, together with pleural plaques and involvement of part of the cardiac margin or diaphragmatic surface.

Pneumoconiosis stage 3

The presence of large shadows with a long diameter of not less than 20 mm and a short diameter of more than 10 mm.

There are small shadows of overall density grade 3, spread over more than 4 lung regions with clustering of small shadows.

There are small shadows of overall denseness grade 3, distributed over more than 4 lung areas and with large shadows.

Exposure to asbestos dust with small shadows of overall density grade 3 spreading over more than 4 lung areas, together with single or bilateral multiple pleural patches whose combined length exceeds one-half of the length of the unilateral chest wall or which involve the cardiac margins so that parts of them appear disorganized.

Differential Diagnosis

The clinical symptoms of pneumoconiosis are similar to those of tuberculosis, idiopathic pulmonary hemosiderosis, tuberculosis, lung cancer, etc., which need to be differentiated by combining with the medical history, laboratory examination and imaging examination.

Tuberculosis

In addition to cough, sputum, chest tightness and other symptoms, it may be accompanied by afternoon low-grade fever, hemoptysis, night sweats and unexplained weight loss. The patient has no occupational history and no history of exposure to productive mineral dust.

Combined with the history of exposure to Mycobacterium tuberculosis, clinical manifestations and a positive tuberculin test, as well as imaging dynamic observation can mostly clarify the differential diagnosis.

Idiopathic pulmonary ferritinosis

It is mainly seen in children, often with unexplained iron deficiency anemia as the earliest clinical manifestation and lack of respiratory symptoms. During acute hemorrhage there may be blood in the sputum or even hemoptysis, low-grade fever, and chest pain.

Chest X-ray typically shows diffusely distributed patchy shadows with indistinct margins in the middle and lower lung fields of both lungs. The patient had no occupational history of productive mineral dust exposure.

Nodular disease

In addition to respiratory symptoms, patients may present with multi-system symptoms such as nodular erythema of the skin, subcutaneous nodules, eye pain, dry eyes, diminished vision, dizziness, headache, abdominal pain, and diarrhea.

Typical pathologic features of nodular disease are non-caseating necrotizing epithelioid granulomas with negative antacid staining. The patient had no occupational history of productive mineral dust exposure.

Lung cancer

Patients may present with cough, blood in sputum or hemoptysis, wheezing, chest pain and other symptoms. Lung cancer compression symptoms, such as hoarseness, dysphagia, upper chest venous rage, etc., may appear in the advanced stage.

X-ray chest film, PET-CT, bronchoscopy, transcavitary needle aspiration cytology or histology, sputum cytology are helpful for differential diagnosis.

Treatment

Aim of treatment: improve and maintain lung function, reduce patients’ pain, delay disease progression, improve quality of life and social participation, and prolong life.

Treatment principle: Pneumoconiosis patients should be timely separated from dust work, and according to the needs of the disease, comprehensive treatment should be carried out to actively prevent and treat tuberculosis and other complications.

Treatment methods: including general treatment, drug treatment, surgical treatment, whole lung lavage treatment and respiratory rehabilitation treatment.

General treatment

Reasonable oxygen therapy

Controlled oxygen therapy can be considered for those with dyspnea and hypoxia to prevent the complications of chronic hypoxemia.

Nasal catheter oxygen administration is suitable for those with mild to moderate hypoxemia.

Mask oxygenation is generally used for patients who require higher oxygen concentrations.

Home oxygen therapy is available when available.

Nutritional support

Patients are in a high metabolic state and need to ensure adequate nutrition.

For critically ill patients who are unable to eat by mouth, a nasogastric tube or nasojejunal tube may be placed.

Specific nutritional regimens should be developed by professionals on an individual basis.

Rest

Avoid exertion, take proper rest, and closely monitor respiration, heart rate, and blood pressure in order to understand the condition.

For bedridden patients with prolonged illness, they should turn over and pat the back regularly to keep the airway open.

Health management

Quit smoking and avoid second-hand smoke inhalation to avoid accelerated pulmonary fibrosis.

Strengthen sports exercise under doctor’s guidance.

Patients with pneumoconiosis should avoid further exposure to productive mineral dust. Measures may include optimizing respiratory protection in the workplace or changing occupation.

Vaccination against pneumococcus and influenza.

Medication

Pneumoconiosis patients with cough, sputum, chest tightness and shortness of breath as the main clinical symptoms should be treated with symptomatic medication under medical supervision.

Asthma treatment

Helps airway smooth muscle relaxation.

Short-acting β2 agonists can be selected as salbutamol, terbutaline, etc. Long-acting β2 agonists can be selected as salmeterol and formoterol.

Adverse effects are rare, mainly muscle tremor and sinus tachycardia.

Theophyllines

They have relatively weak bronchodilator effect, and also have anti-inflammatory and immunomodulatory effects.

Commonly used aminophylline, dihydroxypropyl theophylline, doxophylline and so on.

Aminophylline is easy to cause gastrointestinal reaction after oral intake, it is better to take it after meal or choose enteric-coated tablets.

Anticholinergic drugs

Anticholinergic drugs have the effect of relaxing bronchial smooth muscle and inhibiting glandular secretion.

Short-acting anticholinergic drugs can choose ipratropium bromide, long-acting anticholinergic drugs can choose tiotropium bromide.

Adverse effects are rare and may include dry mouth, pharyngeal irritation, nausea and cough.

Use with caution in patients with glaucoma and prostatic hypertrophy.

Expectorant treatment

There are many types of expectorant drugs, among which mucolytics are widely used in clinical practice because of their good expectorant effect.

Proteolytic enzyme preparations (e.g. Serrapeptase), polysaccharide fiber decomposers (e.g. Bromhexine, Ambroxol), disulfide bond cleavage agents (e.g. N-acetylcysteine, Carboxymetholestane), etc. are commonly used.

Mild adverse reactions such as heartburn and dyspepsia may occur, and nausea and vomiting are occasionally seen.

Cough suppressants

Central cough suppressants

By directly inhibiting the medullary cough center and play a role, but not conducive to sputum coughing out, need to be used with caution.

Commonly used codeine, dextromethorphan and so on.

Codeine has a strong cough suppressant effect and is addictive and dependent. It can be used for dry and irritating cough, especially with chest pain.

Dextromethorphan has no addictive and analgesic effects. It is suitable for coughs with little or no sputum, and should not be used for those with a lot of sputum.

Peripheral cough suppressants

Acts by inhibiting cough reflex receptors as well as effectors.

Nyquiline is available, non-dependent and suitable for different causes of cough.

Surgical treatment

Pneumoconiosis is a chronic disease that generally has little impact on life expectancy in the absence of serious complications. Therefore, lung transplantation is not usually recommended as a treatment option for pneumoconiosis.

In a small number of severe cases, it is recommended to consult your doctor if you meet the surgical indications for lung transplantation before considering surgical treatment.

Whole Lung Lavage

Whole-lung lavage can wash out the sputum and secretions retained in the respiratory tract, which can improve the clinical symptoms in the short term, but it has no obvious effect on improving lung function and slowing down the progression of the disease.

In cases of pneumoconiosis, whole-lung lavage is able to remove relatively large amounts of dust, cells and soluble substances from the lungs.

It is generally not used as a routine treatment for pneumoconiosis. Only in cases where there is a large amount of sputum that cannot be easily coughed up and is blocking the airways, the doctor will consider whole-lung lavage on balance.

Respiratory Rehabilitation

The main objective of respiratory rehabilitation is to enhance the function of respiratory muscles, reserve and utilize the respiratory compensatory potential, which can improve the symptoms, quality of life, lung function and the use of medical resources of patients with chronic respiratory diseases.

Respiratory rehabilitation is the main component of rehabilitation for patients with pneumoconiosis, which requires early intervention and long-term (or even lifelong) continuous treatment in order to achieve good benefits.

Patients need to undergo respiratory control training, respiratory muscle training, chest relaxation training, cough training, postural expectoration method, strength and endurance training and aerobic exercise under the guidance of rehabilitation doctors.

Precautions

Family members should accompany the patient during the training process to prevent accidents such as falling and falling out of bed.

Choose the right time to exercise, and do not train on an empty stomach or on a full stomach after meals.

If you feel unwell during training, stop training immediately and relax at the right time.

Ensure that the training intensity is appropriate, and gradually increase the training frequency.

Prognosis

Cure

If patients with pneumoconiosis are timely removed from the dust environment and actively treated, most of them can achieve the effect of reducing symptoms, delaying the progression of the disease, increasing the survival benefit, prolonging the life of the patients and improving the quality of life.

Hazards

Pneumoconiosis usually has a long duration of illness. Even if a patient is removed from the dust environment, his/her condition will still progress and aggravate, thus requiring lifelong rehabilitation treatment, which will impose a greater financial burden on the patient and his/her family.

Pneumoconiosis patients are prone to complications such as pneumogenic heart disease, pneumothorax, chronic obstructive pulmonary disease, etc., which directly affects the progression and prognosis of the disease, and further affects physical health and quality of life, and in serious cases, can be life-threatening.

Daily

Daily Management

Dietary management

Can eat according to the nutritional supply program under doctor’s guidance.

For those who can eat normally by mouth, it is advisable to increase the intake of high quality and high protein (e.g. eggs, milk, lean meat, etc.), maintain food diversity and balanced nutrition.

If there is no cardiac or renal insufficiency, more water can be consumed in moderation to replenish the consumed water and dilute the sputum, which is favorable for sputum discharge.

Life management

Combine work and rest, pay attention to rest, avoid staying up late.

The more seriously ill should rest in bed to reduce physical exertion and oxygen consumption, and minimize self-care activities and unnecessary operations.

When respiratory effort can try to take a semi-recumbent position or sitting position, lying down on the bed table, in order to improve the respiratory situation.

Long-term bedridden people should have regular lower limb massage to prevent lower limb deep vein thrombosis.

Observe the weather changes and increase clothing appropriately in cold weather.

Smoking must be stopped and second-hand smoke must be avoided.

Family members can help the patient to perform dorsal percussion and sputum expulsion to promote the expulsion of sputum.

Dorsal percussion should be performed 2 hours after a meal to 30 minutes before a meal to avoid triggering vomiting.

The percussionist bends the fingers of both hands together so that the side of the palm is in the shape of a cup, and then percusses the chest wall from the bottom to the top of the lungs, from the outside to the inside, rapidly and rhythmically with the force of the wrist.

Each side of the percussion 1 ~ 3 minutes, percussion issued a hollow and deep beat sound is shown to percussion technique is correct.

The force of percussion should be moderate, so that the patient does not feel pain.

Close attention should be paid to the patient’s response during percussion.

Exercise management

Adhere to the respiratory rehabilitation therapy according to the doctor’s guidance and recommendations.

Avoid activities with high oxygen consumption in a gradual manner.

Psychological support

Due to the long duration of pneumoconiosis, tension and anxiety will often arise. The patient should face the disease with a positive and optimistic attitude and set up confidence to overcome the disease.

Family members should give more psychological care to the patients and encourage them to tell the factors that cause or aggravate anxiety.

If possible, the patient can be counseled by a psychotherapist.

Disease monitoring

Normally, attention should be paid to monitoring the respiratory rate, blood pressure, heart rate, sputum volume and character.

If symptoms worsen, or new symptoms appear, consult a doctor promptly.

Prevention

Occupational hygiene monitoring should be carried out regularly in dusty workplaces to control the air concentration of dust in the workplace within the occupational exposure limits.

Workers working with dust should use protective equipment and wear dust masks and helmets to prevent dust from entering the human respiratory tract.

Undergo regular medical checkups and actively treat lung diseases.

Strengthen sports and exercise, which is conducive to improving immunity and enhancing body resistance.