Respiratory Diseases

There are many different types of respiratory diseases that interfere with the vital process of breathing. Respiratory obstructions arising from diseases can occur in the nasal area, the regions of the throat and windpipe (upper respiratory system), or in the bronchial tubes and lungs (lower respiratory system). The common cold and allergic reactions to airborne pollens block the nasal passages by creating nasal inflammation (rhinitis). Viral and bacterial infections of the upper respiratory tract inflame various parts of the airways. These infections lead to fever, irritation, coughing, and phlegm, which is mixture of mucus and pus. Inflammations may occur in the throat (pharynx), tonsils, larynx, and bronchial tubes. Damage to these parts of the respiratory system and to the lungs can also result from the inhalation of tobacco smoke, air pollution caused by smog, and industrial waste products.

With the mid-twentieth-century discovery and use of antibiotics, the two major respiratory killers of the past, tuberculosis and pneumonia, were brought under control. In place of those diseases, lung cancer began to emerge in the 1940s as an epidemic disease among those who are heavy smokers of cigarettes and those who are exposed to some forms of hazardous environmental pollution. Worksite populations exposed to such materials as asbestos, chromium, and radioactive substances were also found to have a higher incidence of lung cancer.

Colds, like flu and allergies, challenge the breathing process. There are no cures for these conditions, but they are usually not life threatening, unlike many other respiratory diseases. Prescription medicines and over-the-counter medications may provide temporary relief of the discomforts associated with colds, flu, and allergies, while asthma, tuberculosis, and other respiratory diseases require long-range medical attention and supervision.

Colds

The entire tubular system for bringing air into the lungs is coated by a moist mucous membrane that helps to clean the air and fight infection. In the case of a cold, the mucous membrane is fighting any one of over 200 viruses. If the immune system is unsuccessful in warding off such a virus, the nasal passages and other parts of the upper respiratory tract become inflamed, swollen, and congested, thus interfering with the breathing process. The body uses the reflex actions of sneezing and coughing to expel mucus, a thick sticky substance that comes from the mucous membranes and other secretions. These secretions come up from the infected areas as phlegm.

Coughing is a reflex action that helps to expel infected mucus or phlegm from the airways of the lungs by causing the diaphragm to contract spasmodically. It is characterized by loud explosive sounds that can often indicate the nature of the discomfort. While coughing is irritating and uncomfortable, losing the ability to cough can be fatal in an illness such as pneumonia, where coughing is essential to break up the mucous and other infected secretions produced by the body in its battle against the disease.

Antibiotics kill bacteria but not viruses; hence they are not effective against cold viruses. The body has to build up its own defense against them. Since there are so many different types of viruses that can cause a cold, no vaccine to protect against the cold has as yet been developed. Though the common cold by itself is not a serious condition, it poses a threat because of the complications that may arise from it, especially for children, who are much more prone to colds than older people. Colds are usually contracted in the winter months, but there are other seasonal conditions that make individuals receptive to colds.

Influenza

Other viruses cause different types of influenza, such as swine flu, Asian flu, Hong Kong flu, and Victoria flu. Some of the symptoms of influenza resemble the common cold, but influenza is a more serious condition than a cold. It is a disease of the lungs and is highly contagious. Its symptoms include fever, chills, weakness, and aches. It can be especially dangerous to the elderly, children, and the chronically ill. After World War I, a flu epidemic killed 20 million people throughout the world. Fortunately, there has so far not been a repetition of such a severe strain of flu. Flu vaccines provide only seasonal immunity, and each year new serums have to be developed for the particular strain that appears to be current in that period of time.

Allergic rhinitis

Every season throughout the world, ragweed and pollens from grasses, plants, and trees produce the reactions of sneezing, runny nose, swollen nasal tissue, headaches, blocked sinuses, fever, and watery, irritated eyes in those who are sensitive to these substances. These are the symptoms of hay fever, which is one of the common allergies. The term hay fever is really a misnomer because the condition is not caused by hay and does not cause fever. Allergic respiratory disturbances may also be provoked by dust particles. Usually, the allergic response is due more to the feces of the dust mite that inhabits the dust particle. The dust mite's feces are small enough to be inhaled and to create an allergic respiratory response.

Colds and allergic rhinitis both cause the nasal passages and sinuses to become stuffed and clogged with excess mucous. In the case of a cold, a viral infection is responsible for the production of excess mucus. Inhaling steam with an aromatic oil is recommended for the cold. Decongestants are recommended to avoid infection from the excess mucous of the common cold. In seasonal allergic rhinitis, the symptoms result from an exaggerated immune response to what, in principle, is a harmless substance. Histamines released by the mast cells play a major role in an allergic immune response, and it is these chemicals, for the most part, that are responsible for the allergy symptoms.