Types of Lung Diseases, Symptoms, & Causes

The respiratory or airway system plays a crucial role in supplying the body with oxygen, serving as essential fuel for all bodily functions. Additionally, it facilitates the removal of carbon dioxide waste, eliminates toxic substances, regulates temperature, and maintains the blood's acid-alkaline balance (pH). The lungs, the primary component of the respiratory system, fulfill both "respiratory" and "non-respiratory" functions. The respiratory aspect involves the exchange of gases, transferring oxygen from the air into the bloodstream and expelling carbon dioxide from the blood. Meanwhile, the non-respiratory functions of the lungs encompass mechanical, biochemical, and physiological processes. These functions include defending against infectious agents, eliminating various metabolic waste products, controlling the flow of water, ions, and large proteins across cellular structures, and producing essential hormones and chemical agents vital for biological processes.

Respiratory diseases can originate from various causes such as exposure to toxic substances, accidents, and detrimental lifestyles like smoking. Infections, genetic factors, and influences on lung development, whether direct or indirect, can manifest as respiratory symptoms. Over the past two centuries, the landscape of lung diseases has transitioned from infections like tuberculosis and pneumonia to ailments associated with air pollution, such as chronic obstructive pulmonary disease, asthma, and lung cancer. Industrial pollution and HIV infection have given rise to new diseases, while improved imaging techniques have unveiled previously unrecognized conditions. Advances in microbiology, imaging, and clinical measurement have enhanced diagnosis and enabled more targeted treatments.

Remarkable strides in treatment include drugs (such as antibiotics, cortisone, β2-adrenoceptor agonists), ventilatory support (evolving from iron lung to nasal positive-pressure ventilation), inhaled therapy (including metered dose inhalers and nebulizers), and lung surgery (ranging from resections to video-assisted thoracoscopic surgery and transplantation). The delivery of care has evolved from exclusive sanatoria for the wealthy to universal coverage in both primary and hospital care. Generalists have become super-specialists, and the medical field has seen the inclusion of various professions allied to medicine. Although the management of lung disease has significantly improved, the impact of these diseases persists. 

Scientific advancements and serendipity often precede new treatments by 10–50 years. The introduction of the three main types of treatments, drugs, devices, and surgery, differs significantly in their impact on the healthcare market. Advances in surgery, although slower and less visible to patients and primary care, play a substantial role in improving overall respiratory health.

However, knowing the lung diseases well before getting them can help you in keeping them at a bay or taking treatment at earliest. Medflick is going to deliver you some important information you need to know about types of lung diseases, symptoms, & causes.

Lung diseases are the disorders that hinder the proper functioning of the lungs, impacting both respiratory function (the ability to breathe) and pulmonary function (how well the lungs operate). Numerous lung diseases result from bacterial, viral, or fungal infections, while others are associated with environmental factors like asthma, mesothelioma, and lung cancer. Chronic lower respiratory diseases, including chronic obstructive pulmonary disease (COPD), emphysema, and chronic bronchitis, collectively stand as a prominent cause of death in the United States and various other countries.

Conditions like asthma and COPD involve the narrowing or blockage of airways, limiting airflow. In contrast, pulmonary fibrosis, marked by lung tissue scarring, and pneumonia, a bacterial or viral infection causing fluid-filled air sacs, result in reduced lung air-holding capacity.

Lung cancer, characterized by abnormal cell growth, can originate in the lungs or spread from other body parts. The two main types, small cell and non-small cell lung cancer, exhibit distinct growth patterns and may require different treatments.

Cigarette smoking is the primary contributor to lung cancer, and exposure to secondhand smoke also increases the risk of developing the disease. Other environmental factors linked to lung disease include asbestos, radon gas, air pollution, and various chemicals like uranium, beryllium, vinyl chloride, and arsenic. 

1. Airway Diseases (Lung diseases affecting the airways) 

It involve the branching tubes known as bronchi, stemming from the windpipe (trachea) and extending throughout the lungs. These conditions include:

• Asthma, which is characterized by constant inflammation of the airways, leads to spasms that result in wheezing and difficulty breathing. Triggers for asthma symptoms may include allergies, infections, or exposure to pollution
• Chronic obstructive pulmonary disease (COPD) is a lung condition that hinders the usual exhalation process, causing breathing difficulties
• Chronic bronchitis is a type of COPD characterized by a persistent, prolonged wet cough.
• Emphysema is a COPD variant that is characterized by lung damage which results in the trapping of air in the lungs, with a distinctive difficulty in exhaling
• Acute bronchitis is a sudden infection of the airways is typically caused by a viral agent.
• Cystic fibrosis is a condition that impairs the clearance of mucus from the bronchi, leading to recurrent lung infections

2. Air sac diseases (Lung diseases affecting the air sacs)

Our airways branch into bronchioles, which are tiny tubes that end in alveoli, which are collections of air sacs. These air sacs make up the majority of lung tissue. To conceptualize, imagine the alveoli as an empty cup, and the classification of alveolar diseases is based on the content within this cup. These diseases are characterized by the filling of alveoli with substances that hinder their normal physiological function, particularly ventilation. Alveolar diseases can manifest as either localized (focal) or diffuse, and the nomenclature of each condition depends on the nature of the material filling the alveoli. Various Types of alveolar lung diseases:

• Alveoli filled with serous fluid (cardiogenic and noncardiogenic edema): It is the leakage of fluids from tiny blood vessels in the lung tissue into the air sacs and adjacent areas. 
• Alveoli filled with blood (pulmonary hemorrhage): It often attributed happens due to vasculitis (blood vessel damage) e.g., Churge-Strauss syndrome
• Alveoli filled with pus (pneumonia): It is an infection affecting the alveoli that is caused by bacteria or viruses, such as the coronavirus that causes COVID-19
• Alveoli filled with proteins (alveolar proteinosis and amyloidosis): In this, protein material gets accumulated in the alveoli
• Alveoli filled with malignant cells (bronchoalveolar carcinoma): It can manifest in a variety of ways and begin in any part of the lungs, but it most commonly occurs in the central region, near or within the air sacs
• Alveoli filled with calcium (alveolar microlithiasis): In this disorder, calcium gets accumulated in the alveoli

3. Interstitium Diseases (Lung diseases affecting the interstitium)

Interstitum is the fragile layer between your alveoli. The interstitium contains tiny blood vessels facilitating gas exchange between the alveoli and the bloodstream. These diseases include:

• Interstitial lung disease (ILD) is set of lung conditions such as sarcoidosis, idiopathic pulmonary fibrosis, and autoimmune diseases
• Pneumonia and pulmonary edema can also impact the interstitium

4. Pulmonary Blood Vessel Diseases (Lung diseases affecting blood vessels) 

Pulmonary circulation involves the pulmonary arteries that carry low-oxygen blood from the veins to the right side of the heart and then into the lungs. Conditions affecting these blood vessels include:

• Pulmonary embolism occurs when a blood clot, typically from a deep leg vein (deep vein thrombosis), breaks off, travels to the heart, and lodges in a pulmonary artery, often causing shortness of breath and low blood oxygen levels
• Pulmonary hypertension is characterized by high blood pressure in the pulmonary arteries, which can result in shortness of breath and chest pain. If the cause is unknown, it is termed idiopathic pulmonary arterial hypertension

5. Pleural Diseases (Lung diseases affecting the pleura)

Pleura is the thin lining surrounding the lungs and lining the chest wall. Lung diseases affecting the pleura include:

• Pleural effusion is accumulation of fluid between the lung and chest wall, usually caused by pneumonia or heart failure. Large pleural effusions can impede breathing and may require drainage
• Pneumothorax is characterized by entry of air into the space between the chest wall and lung, leading to lung collapse
• Mesothelioma is a rare cancer that develops on the pleura, often occurring decades after exposure to asbestos

6. Chest Wall Diseases (Lung Diseases Affecting the Chest Wall)

The chest wall plays a crucial role in the respiratory pump, which is responsible for facilitating the movement of gas from the atmosphere to the alveoli and vice versa. Conditions that modify the chest wall's structure can impede the functioning of the pump, leading to respiratory challenges or failure. Components of the chest wall encompass bony structures (ribs, spine, sternum), respiratory muscles, and nerves connecting the central nervous system to the respiratory muscles. The various forces impacting the mechanical framework of the chest wall significantly influence lung volume, and any abnormalities in the chest wall can notably affect lung function. Chest wall diseases that affect respiratory function are.

• Obesity hypoventilation syndrome is characterized by the presence of excess weight on the chest and abdomen can hinder chest expansion, leading to significant breathing difficulties
• Neuromuscular disorders are characterized by challenges in breathing that may arise when the nerves controlling respiratory muscles do not function properly. Examples of neuromuscular lung diseases include amyotrophic lateral sclerosis and myasthenia gravis

Q1: What are the 7 most common lung diseases?

A: The 7 most common lung diseases, asthma, pneumothorax or atelectasis, bronchitis, COPD, lung cancer, pneumonia, and pulmonary edema.

Q2: What are the 4 main categories of lung diseases?

A: The 4 main categories of lung diseases are lung diseases affecting the airways, lung diseases affecting the air sacs, lung diseases affecting the interstitium, and lung diseases affecting blood vessels.

Q3: What are 10 different lung diseases?

A: The 10 different lung diseases are COPD, lung cancer, asthma, pneumonia, bronchitis, bronchiectasis, pulmonary fibrosis, cystic fibrosis, hypertension, and pleural effusion.

Q4: What are the 5 restrictive lung diseases?

A: The 5 restrictive lung diseases Idiopathic pulmonary fibrosis (IPF), Non-specific interstitial pneumonia (NSIP), Cryptogenic organizing pneumonia (COP), Sarcoidosis, and Acute interstitial pneumonia (AIP).