Black Lung Disease

Black Lung Disease is a type of an occupational illness that could affect anyone.

Black Lung Disease is otherwise called as Coal Worker’s Pneumoconiosis. The other term of this condition was derived from the fact that the population which has the highest incidence of having the disease consists of coal workers.

It is a form of pneumoconiosis that refers to a non-neoplastic changes that occurs in the lungs due to the frequent inhalation of inorganic or mineral substances. Many people do not show any signs and symptoms of the disease but it is a chronic condition that can cause disability or untimely death if it is left untreated.

The structure involved in this condition are the organs of the respiratory system especially the alveoli, bronchi and bronchioles of the lungs. The main role of the respiratory system is to provide oxygen to every part of the body and to remove carbon dioxide from the blood. The bronchi and bronchioles are the channels where air travels from the trachea to the alveoli, where gas exchange occurs.

How Does Black Lung Disease Come about in the Body?

Coal Worker’s Pneumoconiosis involves the deposition of coal dusts in the alveoli of the lungs and other respiratory system organs such as the bronchi and bronchioles. Dust particles are engulfed by macrophages in the process of phagocytosis  and eventually transfer them to the terminal bronchioles where mucociliary action takes place to remove them. There will come a time that the clearance mechanism will not be able to manage the accumulation of  dust  and macrophages in the respiratory system. The coal dust will aslo stimulate the macrophages to release cytokines, enzymes and fibroblast growth factors. Fibroblasts will then form and a reticulin network will encirlce the dust-loaded macrophage.

The dust-loaded macrophages causes the alveoli and bronchioles to be clogged by dust particles, firbroblasts, and dying macrophages. This will result to the formation of the coal maculae, the principal lesions of the disease which appear as black lesions in the lungs. The deteriorating bronchioles dilate and consequently develop localized emphysema, a chronic condition that can impair the function of the lungs. It begins on the upper portion of the lungs then progresses to the lower lobes.

What are the Clinical Manifestations?

The primordial signs are sputum production and chronic cough comparable to the signs associated with chronic bronchitis. As the condition advances, the patient develops unceasing cough, large quantities of sputum with unstable amounts of melanoptysis (black-stained sputum) and dyspnea or difficulty of breathing. If the disease is left untreated, it can lead to respiratory failure and cor pulmonale, a type of heart disease that usually leads to right sided heart failure.

How is Black Lung Disease Diagnosed?

The diagnostic tests that are used for this condition includes taking the health history of the patient. It is important to be able to identify whether the patient has been exposed to coal dust particles. Pulmonary function studies are also utilized to help substantiate the diagnosis of the deteriorating function of the respiratory system in this condition.

Spirometry is used to assess airflow occlusion. It uses a special device, called a spirometer,  that measures the volume of air inhaled and exhaled by the lungs.  Arterial Blood Gas or ABG analysis can also be performed to evaluate the gas exchange and baseline oxygenation in the body. Chest X-ray is performed to visualize the extent of the coal maculae damage.

What are the Complications of Coal Worker’s Pneumoconiosis?

Complications are anticipated to occur because it is a life time progressive disease. A patient can develop Cor Pulmonale, also known as pulmonary heart disease. This happens because of the increase in the blood pressure of the lungs and the right ventricles of the heart enlarges and the veins and arteries dilate. There is a tendency for the blood to backflow to the ventricle instead of proceeding to the lungs. The lungs will not be able to oxygenate the blood that comes from the right ventricle of the heart. As a result, deoxygenated blood will return to the right atrium and eventually, goes back to the systemic circulation where it originated.

All parts of the body will be affected because of the decrease in oxygenation. The right ventricle will try to compenssate and enlarge even more. When it becomes overloaded with work and it can no longer compensate, right-sided heart failure will occur which can lead to death.

The other complication of this disease is Emphysema (a type of COPD or Chronic Obstructive Pulmonary Disease) because the inhalation of coal dusts is one of the risk factors that can contribute to this disease. Emphysema is the destruction of the alveoli’s walls that makes it over distended and loses its elasticity. It is an end phase of a progressive disease. As the alveoli’s wall over distend, its surface area for gas exchange also decreases, which in turn, significantly impairs the functions of the lungs. This disease can as well progress to Cor Pulmonale.

What are the Medical Managements for Coal Worker’s Pneumoconiosis?

As of today, there is no effective treatment for Black Lung Disease. The only way to stop it is Prevention. It is essential to avoid the exposure to harmful substances that can cause conditions that can not be treated by the science and technology available today. The management that can be offered to this kind of patients is palliative or symptomatic care.  The patient may be given bronchodilators (Atrovent, Ventolin, Theophylline etc.), steroids (Prednisone), antibiotics and supplementary oxygen.

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