Definition and Overview

The lungs are part of the respiratory system. They are responsible for supplying oxygen and eliminating waste gases so all the organs and body systems can function normally. The lungs are located on either side of the chest, separated by the mediastinum (the area that contains the oesophagus, trachea, and heart), and protected by the rib cage.

Lung disorders are medical conditions that prevent the lungs from working properly. Some of the most common are asthma, chronic obstructive pulmonary disease (COPD), pneumonia, tuberculosis, and lung cancer. Such diseases, which can be caused by genetics, smoking, air pollution, exposure to occupational chemicals, and certain types of infections, usually present the following symptoms: breathing difficulty, chronic cough, wheezing, and chest pain. Advanced or more serious cases can cause a person to cough up blood, develop chronic infections that do not go away despite treatment, and respiratory failure.

Lung disorders are some of the most common medical conditions in the world affecting all types of people – men, women, children, the elderly, smokers, and non-smokers. According to the World Health Organisation (WHO), about 235 million people in the world suffer from asthma and about three million die each year due to COPD. Meanwhile, lung cancer remains to be the leading cause of cancer deaths among both men and women, accounting for about one in every four cancer deaths. Lung disorders are also the leading cause of death among infants under the age of one.

Causes of Condition

The majority of lung disorders are caused by smoking. Cigarette smoke contains toxins that interfere with the body’s method of filtering the air it takes in and cleaning out the lungs. It also damages the cilia (microscopic structures responsible for removing dust and dirt from the air a person breathes) and causes the overproduction of mucous, which can lead to the accumulation of toxic substances in the lungs.

Long-term exposure to cigarette smoke can lead to irreversible damage to the lung structure. This affects the lungs’ ability to efficiently transfer oxygen to the blood, resulting in breathing difficulty and other symptoms.

Other causes of lung disorders include:

  • Air pollution - Just like cigarette smoking, air pollutants also cause serious damage to the respiratory tract. They can trigger new cases of asthma and exacerbate chronic lung disorders such as emphysema, lung cancer, and COPD.

  • Asbestos - Asbestos is a naturally occurring mineral that has been linked to lung tissue scarring, pleural disease, and lung cancer. This mineral, which has been widely used in a variety of building materials as a fire retardant in the past, is now most commonly found in older homes.

  • Radon - A radioactive, odourless, and invisible gas that is also naturally found in the environment. It is produced by the decay of uranium found in water, rock or soil. Radon levels are generally highest in crawl spaces and poorly ventilated areas.

Key Symptoms

The most common symptoms of lung disorders are breathing difficulty or shortness of breath, wheezing, cough, and chest pain. Other symptoms may include airway inflammation, chest tightness, frequent respiratory infections, and excess mucous production in the lungs.

When left untreated, lung disorders can cause unintended weight loss, cyanosis (bluish discolouration of skin and lips due to lack of oxygen in the blood), coughing up blood, and swelling.

Who to See and Types of Treatments Available

A person who experiences the above symptoms can consult a general practitioner (GP) or family doctor for initial medical assessment. If a lung disorder is suspected, the patient will be referred to pulmonologist or paediatric pulmonologist (if the patient is a child or adolescent) who specialises in the diagnosis and treatment of all lung (pulmonary) conditions and diseases.

To diagnose the condition, pulmonologists usually start with the review of the patient’s medical history, a thorough physical examination, and chest x-ray, an imaging test that produces detailed pictures of the lungs, airways, and blood vessels. It is often very useful in identifying any abnormalities such as air or fluid build-up in the lungs. Depending on the results of initial tests, the following may also be carried out:

  • Pulmonary function tests - These are noninvasive tests that measure how well the lungs are working.

  • Bronchoscopy - A procedure that uses an endoscope to visualise the airways for diagnostic and/or therapeutic purposes.

  • Thoracoscopy - Involves inserting an endoscope through a small incision in the chest wall to examine the lungs and other structures in the chest cavity. It can also be performed to deliver medications directly into the lungs or remove pus and fluid that have accumulated in the area.

  • Electrocardiography (ECG) and echocardiography - These are carried out to ensure that shortness of breath or breathing difficulty is not caused by heart disorders.

  • Needle biopsy - This is usually performed as a follow-up procedure when nodules are found by imaging tests but doctors cannot confirm if the growths are malignant (cancerous) or benign (non-cancerous). Using a needle, a small tissue sample is removed and studied under a microscope.

Different lung disorders require different therapies. While minor cases can be treated with medications, ample rest, and drinking plenty of fluid, severe conditions often require surgical procedures. Asthma, for example, is often managed with medications like corticosteroids, leukotriene modifiers, and inhalers. Lung cancer, on the other hand, often requires surgical procedures to remove the part of the lung where the malignant tumour is found. These procedures are often followed by chemotherapy and radiation therapy to kill any remaining cancer cells.

People with lung disorders are carefully assessed before any type of treatment is initiated. Their symptoms, general health condition, and the severity of their disease are taken into consideration when doctors design an individualised treatment for them. Their prognosis depends on many factors including their age, whether or not they are suffering from other medical conditions, and their body’s response to treatment. The prognosis is often worse when lung diseases develop in patients who are already hospitalised due to chronic illnesses or serious medical conditions.


  • Witt WP, Wiess AJ, Elixhauser A (December 2014). “Overview of Hospital Stays for Children in the United States, 2012”. HCUP Statistical Brief #186. Rockville, MD: Agency for Healthcare Research and Quality.

  • Wier, L. M.; Hao, Y.; Owens, P.; Washington, R. (May 2013). “Overview of Children in the Emergency Department, 2010”. HCUP Statistical Brief #157. Agency for Healthcare Research and Quality. Rockville, MD.

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