The Lungs

Lung Disease

Lung Disease

There are a number of infections which can seriously affect the lungs and their function.

Pulmonary tuberculosis

This is an infectious disease which is, in most cases, fatal. It’s spread through the air, for example when a sufferer sneezes or coughs.

The main cause of pulmonary tuberculosis (TB) is a bacterium called Mycobacterium tuberculosis. It’s able to survive weak disinfectants and live in a dry state for a period of weeks. When a sufferer coughs, sneezes or even speaks, infectious aerosol droplets able to transmit the disease are released into the air. One sneeze can release around 40,000 droplets.

When bacterial cells are inhaled they invade the epithelial cells located in the bronchioles and alveoli. Here they multiple into lumps known as tubercles. The bacteria is still alive in this state but dormant. In the body, an inflammatory response is triggered but this only makes the situation worse by causing fibrous scar tissue to form. The walls of the alveoli lose their elasticity and thicken which leads to the rate of oxygen diffusion decreasing.

Pulmonary Fibrosis

This is where an excessive amount of fibrous connective tissue is produced in the lungs. Sometimes it’s a secondary effect of another disease, like a viral infection or lung injury. However, it can also have no known cause which is known as idiopathic pulmonary fibrosis. Cigarette smoking, radiation therapy to the chest and certain medications can also cause it.

The effect of this disease is an exchange of the lung’s parenchyma with the fibrotic tissue. This decreases the amount of oxygen that can be taken in by the lungs. It’s known as a restrictive lung disease because it reduces the lung volume making it harder for a sufferer to take in enough oxygen.

Symptoms include:

  • shortness of breath
  • hacking cough
  • fatigues
  • discomfort in the chest
  • loss of appetite