Pneumonia is an inflammation of the lung most often caused by infection with bacteria, viruses, and other organisms although there are also non-infectious causes. Pneumonia is often a complication of a pre-existing condition/infection and triggered when a patient’s defense system is weakened, most often by a simple viral respiratory tract infection or a case of influenza, especially in the elderly. Pneumonia affects the lungs in different ways. Lobar pneumonia affects a lobe of the lungs, and bronchial pneumonia can affect patches throughout both lungs. Together, pneumonia and influenza represented a cost to the U.S. economy in 2005 of $40.2 billion, $6 billion due to indirect mortality costs and $34.2 billion in direct costs.
Pneumonia and influenza together are ranked as the eighth leading cause of death in the United States. Pneumonia consistently accounts for the overwhelming majority of deaths between the two. In 2004, 60,207 people died of pneumonia.
There were an estimated 651,000 hospital discharges in males (44.9 per 10,000) and 717,000 discharges in females (47.7 per 10,000) all attributable to pneumonia in 2005. The highest pneumonia discharge rate that year was seen in those 65 and over at 221.3 per 10,000.
Pneumonia is mainly caused by viruses, bacteria and other organisms. Pneumonia can also be caused by the inhalation of food, liquid, gases or dust. One type of pneumonia caused by fungi is pneumocystis carinii pneumonia (PCP) which primarily affects AIDS patients. Certain diseases, such as tuberculosis, can also predispose someone to pneumonia.
Approximately 50 percent of pneumonia cases are believed to be caused by viruses and tend to result in less severe illness than bacteria-caused pneumonia. Most pneumonia in the very young is caused by viral infection, including respiratory syncytial virus (RSV). The symptoms of viral pneumonia are similar to influenza symptoms and include fever, dry cough, headache, muscle pain, weakness, fever and increasing breathlessness.
Streptococcus pneumoniae or pneumococcal pneumonia is the most common cause of bacterial pneumonia acquired outside of hospitals. The bacteria can multiply and cause serious damage to healthy individual lungs, bloodstream (bacteremia), brain (meningitis) and other parts of the body, especially when the body’s defenses are weakened. Pneumococcal pneumonia accounts for 25 to 35 percent of all community-acquired pneumonia, and an estimated 40,000 deaths yearly.
The onset of bacterial pneumonia can vary from gradual to sudden. In most severe cases, the patient may experience shaking/chills, chattering teeth, severe chest pains, sweats, cough that produces rust colored or greenish mucus, increased breathing and pulse rate, and bluish colored lips or nails due to lack of oxygen.
Mycoplasmas are the smallest free-living agents of disease in man, with characteristics of both bacteria and viruses. The agents generally cause a mild and widespread pneumonia. The most prominent symptom of mycoplasma pneumonia is a cough that tends to come in violent attacks, but produces only sparse whitish mucus. Mycoplasmas are responsible for approximately 15-50 percent of all adult cases of pneumonia and an even higher rate in school-aged children.
People considered at high risk for pneumonia include the elderly (over 65 years of age), the very young, and those with underlying health problems, such as chronic obstructive pulmonary disease (COPD), diabetes mellitus, congestive heart failure and sickle cell anemia. Patients with diseases that impair the immune system, such as AIDS, or those undergoing cancer therapy or organ transplantation, or patients with other chronic illnesses are particularly vulnerable.
There are no generally effective treatments for most types of viral pneumonia, which usually heal on their own. Early treatment with antibiotics can cure bacterial pneumonia and speed recovery from mycoplasma pneumonia. However, the disease has become more resistant to these drugs, making treatment of pneumococcal infections more difficult.
The pneumococcal polysaccharide vaccine (PPV) is recommended for anyone over 65 years of age, those with serious long-term health problems, anyone with lowered infection resistance, all Alaskan Natives and certain Native American populations.
The pneumococcal conjugate vaccine (PCV) is recommended for children less than 2 years of age and children between 2 and 5 years of age who have serious long-term health problems, lowered infection resistance, are Alaskan Native, Native American, African American, or attends a group day care center.
Overall in 2005, 66 percent of those 65 years of age or older received the pneumonia vaccine.
However, only 51 percent of African Americans 65 years of age or older received the pneumonia vaccine, compared to 68 percent of whites the same age or older. This is despite it being covered by Medicare and available to seniors.
The pneumococcal vaccine protects against 23 types of pneumococcal bacteria populations and is effective in approximately 80 percent of healthy adults. Unfortunately, the vaccine may be less effective in people in high risk groups.
The pneumonia vaccine is generally given once, although revaccination after 3-5 years should be considered for children with nephritic syndrome, asplenia, or sickle cell anemia who would be less than 11 years old at revaccination. Revaccination should also be considered for high risk adults who received their first shot six years ago or more, and for those who are shown to have rapid decline in pneumococcal antibody levels.
Influenza vaccination is also recommended since pneumonia often occurs as a complication of the flu. Pneumonia and influenza vaccines are covered by Medicare, as well as some state and private health insurance.