Pneumonia
Pneumonia is an infection of the lungs that can be caused by many tiny organisms including bacteria, viruses, parasites, and fungi. It can also occur after injury to the lungs from cancer and alcohol abuse. Pneumonia often begins with an infection in the nose or throat. Symptoms include green or yellow sputum that is coughed up, fever, chills, shortness of breath, and chest pain. People may also cough up blood, have sweaty or clammy skin, show loss of appetite, nausea and vomiting, joint pain, weight loss, and muscle aches.
A diagnosis of pneumonia is most easily made from the symptoms given when examined by a doctor or through a chest X-ray. There are several types of pneumonia including hospital acquired pneumonia (patient got it as a result of a hospital stay), community acquired pneumonia, severe acute respiratory syndrome caused by virus, bronchiolitis obliterans organizing pneumonia where parts of the airway become inflamed, aspiration pneumonia caused by vomiting up stomach contents and then inhaling some of them, eosinophilic pneumonia caused by parasites in the blood, and chemical pneumonia caused by inhaling toxic substances.
If not too serious, pneumonia can be treated with rest, antibiotics (for bacterial pneumonia), and fluids. As the severity of the pneumonia progresses hospitalization becomes necessary. Specific treatments depend on what type of pneumonia the person has. If it is bacterial then antibiotics are suggested, viral pneumonias are treated with antiviral drugs. Often hospitalized patients will require oxygen. Pneumonia can be very serious and life threatening causing respiratory and circulatory failure and possibly death. With proper treatment most types of bacterial pneumonia can be treated in a couple of weeks without much problem, viral pneumonia may last longer. The rate of mortality depends on the cause of the pneumonia, but about 20% of people with bacterial pneumonia will die. It is possible to prevent infectious pneumonia by doing things like stopping smoking, treating other illnesses that will compromise the immune system, and getting a flu vaccine.
References:
http://en.wikipedia.org/wiki/Pneumonia
http://www.kidshealth.org/parent/infections/bacterial_viral/pneumonia.html