An insight into respiratory diseases and their clinical presentation

What is the respiratory system? What are the different parts of respiratory system?

Respiratory system/tract is made of the following three parts: airway, lungs, and muscles of respiration known as diaphragm. The airway consists of parts that include the nose, mouth, pharynx, larynx, trachea, bronchi, and bronchioles which end in tiny sacs in the lung called alveoli. The air that we breathe passes through the nose or mouth through the respiratory tract to the smallest bronchioles, and fills the alveoli that perform the function of gaseous exchange. The airway up to the larynx is called upper respiratory tract. The alveoli are supported by a lace like structure in the lungs known as interstitium. It also contains blood vessels for exchange of air with the alveoli. The lungs are surrounded by a soft double layered covering called the pleural membrane, which contains a fluid within, called the pleural fluid. The space between the membranes is called pleural cavity. The cells that line the pleural cavity are known as mesothelium.

The respiratory tract can be affected by many diseases that may arise in the different parts of the system.

What are the respiratory diseases that affect the airways?

Some of the common diseases affecting the airway include:

Asthma: A common disease of the respiratory system, which results in sudden bouts or episodes of coughing, shortness of breath and a whistling sound called wheezing. Asthma results due to inflammation of inner lining of the bronchioles, causing a narrowing of these tubes, due to spasm. It is commonly seen in children or young adults. Asthma gets triggered by irritants like dust, pollen, hay, smoke etc. It can be managed by medications and proper treatment.

COPD (Chronic obstructive pulmonary disease): This is a disease of the lungs that occurs due to long term inflammation of the tissues of the respiratory tract leading to an obstructed airflow from the lungs. It is associated with symptoms like difficulty in breathing, persistent cough, excessive production of mucous and wheezing. It is generally caused by long standing exposure to irritants like cigarette smoke. COPD can be treated with proper management and lifestyle changes.

Chronic bronchitis: An inflammatory disease of the bronchi, it is characterized by long duration coughing and shortness of breath. A diagnosis of chronic bronchitis is usually made when there is a history of daily productive cough lasting for at least three months in a year and at least for two consecutive years. The disease is treatable with appropriate medications and lifestyle modifications.

Acute Bronchitis: An inflammation of the inner lining of the bronchial tubes is called bronchitis. When the condition subsides within a week or a few days more and there are no lasting effects, the condition may be termed as acute bronchitis or chest cold. Post bronchitis cough may persist for a few weeks.

Cystic fibrosis: A disease that occurs due to a defective gene that alters the protein responsible for regulation of movement of salt within and out of body cells. The disease is characterized by accumulation of thick and sticky mucous within the airways leading to breathing difficulties and susceptibility to infections from bacteria and fungi.

Influenza: It is a viral infection of the respiratory system involving the nose, throat and lungs. Also known as “flu”, it is mostly self-resolving. However, in patients of compromised medical conditions, its complications can be life threatening.

What are the respiratory diseases of the air sacs?

Some of the common diseases affecting the air sacs include:

Tuberculosis: It is an infectious disease of the lungs caused by bacteria. Th e disease is communicable, that means it spreads from one person to another through droplets in cough or sneeze.

Pneumonia: It is an inflammatory infection of the air sacs in one or both lungs. Fluid or pus gets filled in the sacs leading to cough with phlegm or pus. It may also cause symptoms like fever, chills and difficulty in breathing. It can be caused by many organisms like bacteria, viruses and fungi.

Emphysema: Damage to the air sacs in the lungs leads to an over inflation of the alveoli, causing shortness of breath.

Pulmonology oedema: Accumulation of an excess fluid in the air sacs causing breathing difficulties. It is mostly caused as a result of heart disease.

Lung cancer: Lung cancers originate in the cells lining the bronchi or other smaller parts of the lung such as the bronchioles or alveoli.

Acute respiratory distress syndrome (ARDS): It occurs due to accumulation of fluid, which obstructs the flow of oxygen within these alveoli. It can be life threatening.

What are the respiratory diseases of the interstitium?

Some of the common diseases affecting the interstitium include:

Pneumoconiosis: It is a group of diseases that occurs due to long term inhalation of harmful particles like dust. Because it is likely to be acquired in work place, it is also called as an occupational lung disease. It may take several years to develop and results in fibrous thickening of lung tissues.

Interstitial lung disease: A group of diseases in which there is a thickening of the supporting tissues, the interstitium between the air sacs of the lungs. This disease generally involves the whole lung.

What are the respiratory diseases of respiratory blood vessels?

Pulmonology oedema: Sometimes, there is seepage of fluid from within the blood vessels to the outside surrounding tissues, either due to a high pressure or inadequate proteins, leads to swelling or oedema. Collection of fluid in the vessels around alveoli causes pulmonary (lung) oedema.

Pulmonology hypertension: An increased blood pressure within the pulmonary (lung) arteries causes symptoms like blackout/fainting, shortness of breath, tiredness, pain in chest, swelling of the legs etc. The risk of pulmonary hypertension is higher in those who have a positive family history, formation of blood clots in bloodstream or lungs, COPD, or live in high altitude places.

What are respiratory diseases of pleura?

Pleurisy: It is an inflammation of the pleural membrane, which is typically characterised by a sharp pain in the chest while breathing. When it is caused due to accumulation of fluid within the pleural space, it is known as pleural effusion, and when there is no fluid accumulation it is called dry pleurisy. The disease can be caused due to infections, rib fracture etc.

Pneumothorax: It is collection of air in the pleural space between the wall of the chest and the lung resulting in a sudden onset of sharp pain in chest on one side and shortness of breath. Pneumothorax is often caused due to trauma.

Mesothelioma: This is a cancer that develops from the mesothelium frequently caused by a long standing exposure to asbestos.

References:

• Milton S Hershey Centre. Anatomy and function of the respiratory system. Available at:http://pennstatehershey.adam.com/content.aspx?productId=28&pid=28&gid=000141. Accessed on March 13, 2018.
• US National Library of Medicine. Lung Diseases. Available at:https://medlineplus.gov/lungdiseases.html Accessed on March 13, 2018
• American Lung Association. Lung Diseases. Available at:http://www.lung.org/lung-health-and-diseases/all-diseases.html Accessed on March 13, 2018