Lung Diseases Overview
Lung Diseases Affecting the Interstitium
The interstitium is the microscopically thin, delicate lining between the lungs' air sacs (alveoli). Tiny blood vessels run through the interstitium and allow gas exchange between the alveoli and the blood. Various lung diseases affect the interstitium:
Lung Diseases Affecting Blood Vessels
The right side of the heart receives low-oxygen blood from the veins. It pumps blood into the lungs through the pulmonary arteries. These blood vessels can suffer from disease, as well.
- Pulmonary embolism (PE): A blood clot (usually in a deep leg vein, deep vein thrombosis) breaks off, travels to the heart, and is pumped into the lungs. The clot lodges in a pulmonary artery, often causing shortness of breath and low blood oxygen levels.
- Pulmonary hypertension: Various conditions can lead to high blood pressure in the pulmonary arteries. This can cause shortness of breath and chest pain. When no cause is identified, the condition is called idiopathic pulmonary arterial hypertension.
Lung Diseases Affecting the Pleura
The pleura is a thin lining that surrounds the lung and lines the inside of the chest wall. A tiny layer of fluid allows the pleura on the lung's surface to slide along the chest wall with each breath. Lung diseases of the pleura include:
- Pleural effusion: Fluid collects in the normally tiny pleura space between the lung and the chest wall. Pneumonia or heart failure is usually responsible. If large, pleural effusions can impair breathing, and should be drained.
- Pneumothorax: Air may enter the space between the chest wall and the lung, collapsing the lung. To remove the air, a tube is typically inserted through the chest wall.
Mesothelioma: A rare form of cancer that forms on the pleura. Mesothelioma tends to emerge several decades after asbestos exposure.
Lung Diseases Affecting the Chest Wall
The chest wall also plays an important role in breathing. Muscles connect the ribs to each other, helping the chest to expand. The diaphragm descends with each breath in, also causing chest expansion.
- Obesity hypoventilation syndrome: Extra weight on the chest and abdomen makes it difficult for the chest to expand. Serious breathing problems can result.
- Neuromuscular disorders: Poor function in the nerves controlling the respiratory muscles causes difficulty breathing. Amyotrophic lateral sclerosis and myasthenia gravis are examples of neuromuscular lung disease.