Definition
Pneumonia is a serious respiratory disease that results when invading microorganisms affect the lungs, causing them to become severely inflamed. As this inflammation occurs, the part of the lung and/or bronchial tubes (bronchi) that are affected lose their natural sponginess, harden, and become less functional. In the United States, pneumonia ranks as the number one fatal infectious disease, killing as many as 70,000 people each year, and affecting another two million. Particularly at risk are children under one year of age, people 60 years and older, smokers, alcoholics, and people with diabetes.

Pneumonia most commonly strikes during winter, but can occur at any time of the year. In addition, it can be contracted by visits to the hospital, and as a result of other health conditions, including, colds and flu, and bronchitis, as well as AIDS and other immunosuppressive diseases, such as cancer.
Caution: If you suspect you have pneumonia, seek immediate medical attention. Left untreated, pneumonia can be fatal.

Types: There are two types of pneumonia—bronchopneumonia and lobar pneumonia. Bronchopneumonia affects only the bronchi of the upper respiratory tract, whereas lobar pneumonia can affect the entire lung.

Symptoms
The most common symptoms of both types of pneumonia are sensations of breathlessness; rapid, shallow breathing; chest pain; a sore throat; a headache; a cough with mucus and/or blood; fever; sweating; and chills and shivering.


Causes of Pneumonia

Approximately half of all pneumonia cases are due to a viral infection. Bacterial infection is another major cause, however, with the most common bacterial causes being Pneumococcus, Staphylococcus, Streptococcus, Klebsiella, E. coli, proteus, Pseudomonas, and Hemophilus. Fungal infections can also play a role in the development and progression of pneumonia, as can other chronic respiratory diseases and diseases that compromise the immune system. Hospitalization and hospital visits can also increase the risk of pneumonia, as can smoking, alcohol and drug abuse, and the use of immunosuppressive medications.

Treatment