Types and Causes of Common Lung Conditions

The lungs are part of a complex system that expands and relaxes thousands of times per day, with the goal of bringing in oxygen and expelling carbon dioxide. Lung disease can result from problems in any part of this system, and tens of millions of people suffer from lung disease in the United States every year. Smoking, infections, and genetics are the three most common causes of these diseases.

There are several different kinds of lung diseases out there, varying by the part of the part of the respiratory system (please link to What is the Respiratory System blog when posted) that they affect.

Airways

The trachea, or windpipe, branches out into smaller tubes called bronchi. The bronchi then branch into even smaller tubes through the lungs. A few diseases can affect this system:

• •Asthma: Persistent airway inflammation that can cause wheezing and shortness of breath
• •Chronic obstructive pulmonary disease (COPD): Lung conditions where you cannot exhale normally, leading to trouble breathing
• •Chronic bronchitis: A form of COPD marked by a chronic productive cough
• •Emphysema: A form of COPD where lung damage allows air to be trapped in the lungs and can make it tough to blow out air
• •Acute bronchitis: A sudden airway infection, generally by a virus
• •Cystic fibrosis: A genetic condition that leads to limited ability to clear mucus from the bronchi, and can cause repeated infections in the lungs

Air Sacs (Alveoli)

Eventually, the airways branch off into small tubes called bronchioles that lead to clusters of air sacs. These air sacs are called alveoli, and they make up most of the lung tissue. Some diseases that affect the alveoli include:

Pneumonia: Generally a bacterial infection of the alveoli

• •Tuberculosis: A progressive form of pneumonia
• •Emphysema resulting from damage to fragile connections between alveoli (generally caused by smoking)
• •Pulmonary edema: When fluid leaks out of the lungs and into the surrounding areas
• •Lung cancer: Comes in many forms, and can develop in any part of the lungs
• •Acute respiratory distress syndrome (ARDS): Sudden, severe injury to the lungs caused by a serious illness. This can be life-threatening and require life support on a ventilator
• •Pneumoconiosis: A group of conditions caused by inhalation of a substance that damages the lungs (black lung disease is a well-known example)

Interstitium

The interstitium is an extremely thin, delicate lining between the alveoli. Small blood vessels run through it, allowing gas to exchange between the alveoli and the blood. Interstitium-related lung diseases include:

• •Interstitial lung disease (ILD): A range of lung conditions that affect the interstitium, including sarcoidosis, idiopathic pulmonary fibrosis, and autoimmune disease
• •Pneumonia and pulmonary edemas can also affect the interstitium

Blood Vessels

When blood has provided oxygen to areas of the body and returned to the heart, it’s received by the right side of the heart. This is the side that pumps blood into the lungs through the pulmonary arteries. Diseases that can affect these blood vessels include:

• •Pulmonary embolism: A blood clot that breaks off, travels to the heart and then is pumped into the lungs and can cause shortness of breath and low blood oxygen levels

•Pulmonary hypertension: High blood pressure in the pulmonary arteries can be caused by a variety of factors, and can lead to shortness of breath and chest pain

Pleura

The pleura is the thin lining surrounding the lungs and lining the inside of the chest wall. A small fluid layer allows the pleura to slide along the chest wall with each breath. Diseases of the pleura can include:

• •Pleural effusion: When fluid collects in the pleura space. This can impair breathing and may need to be drained
• •Pneumothorax: When air enters the space between the chest and the lung, and collapses the lung
• •Mesothelioma: A rare form of cancer that first forms on the pleura – it often emerges several decades after exposure to asbestos

Chest Wall

Muscles in the chest wall connect the ribs to each other, helping as the chest expands. The diaphragm descends every time you breathe in, causing chest expansion. There are a couple lung diseases of the chest wall:

• •Obesity hypoventilation syndrome: When extra weight on the chest and abdomen makes it difficult for the chest to expand as it should, this can result in serious breathing problems
• •Neuromuscular disease: Breathing can be made difficult by poor function in the nerves that control the respiratory muscles

Your doctor can offer further education on the types of lung diseases out there. If you fear you have one of these conditions, see your doctor.

Sources:

“Lung Diseases Overview.” WebMD. https://www.webmd.com/lung/lung-diseases-overview#1

“Lung disease.” MedlinePlus. https://medlineplus.gov/ency/article/000066.htm