July 3, 2014
Table of Contents
Pneumonia refers to a common infection of the lungs caused by one of the following types of germs: bacteria, fungi, or viruses. The infection can involve one lung, both lungs, or just part of a lung. Depending on your overall health, pneumonia and its symptoms can be mild or severe. In more severe cases, pneumonia can require hospitalization and even lead to death. In the US, 1.1 million people were hospitalized with pneumonia in 2010, and almost 50,000 died from the disease. Worldwide, pneumonia is the leading cause of death for children under the age of five. Almost one fifth of all deaths of children under the age of five are due to pneumonia each year.
The symptoms, diagnoses, and treatments listed in this section are broad symptoms common to all types of pneumonia. Some symptoms, like cough with sputum, are characteristic of only certain types of pneumonia (e.g., bacterial pneumonias). Similarly, some treatments, like antibiotics, are indicated for only some types of pneumonia (e.g., bacterial pneumonias, Pneumocystis pneumonia) and not for others (e.g., viral pneumonias). For information specific to each type of pneumonia, please scroll down.
There are many simple things you can do to avoid getting infected with the germs that cause pneumonia. These include washing your hands regularly, cleaning surfaces that are touched often and by many different people (countertops, phones, doorknobs), and coughing or sneezing into a tissue or your elbow or sleeve. You can also prevent pneumonia by stopping or reducing smoking, limiting the time you spend in or around smoke, and by getting vaccinated when appropriate. There are several vaccines that can prevent infection with the bacteria or viruses that cause pneumonia:
People living with HIV (HIV+) are more vulnerable to pneumonias of all kinds because they have a weakened immune system. Certain pneumonias lead to an AIDS diagnosis, such as Pneumocystis (PCP), recurrent pneumonia (more than once in a year's time), and active tuberculosis (TB).
PCP is caused by a fungus called Pneumocystis jiroveci. A healthy immune system can control the fungus. However, in HIV+ people with CD4 cell counts below 200, Pneumocystis can be a problem.
PCP has been the most common opportunistic infection and the most common pneumonia in HIV+ people since the beginning of the AIDS epidemic. While PCP used to be fatal for many HIV+ people, it is now preventable and treatable. Drugs to prevent PCP are recommended for all HIV+ people with CD4 cell counts below 200. Taking drugs to prevent disease is called prophylaxis.
Anyone with these symptoms should see a health care provider immediately.
Bacteria that cause pneumonia are commonly found in the nose and throat. In HIV+ people with weakened immune systems, especially HIV+ women, the bacteria can multiply and work their way into the lungs, causing pneumonia. The most common bacteria to cause pneumonia in the US are Streptococcus pneumoniae (pneumococcus).
About one third of all the pneumonias in the US each year are caused by respiratory viruses. The most common viral cause of pneumonia for adults is the flu virus (influenza). The most common viral cause of pneumonia in children younger than one year of age is respiratory syncytial virus (RSV). In HIV+ children, cytomegalovirus-associated pneumonias are also common.
TB often occurs as a lung infection, but can affect almost any organ of the body. Mycobacterium tuberculosis, the bacterium that causes TB, can spread when a person with active TB disease coughs, sneezes or spits. Tiny droplets of fluid from the lungs are carried in the air and can be inhaled by someone nearby.
In healthy people, the immune system can usually prevent the bacteria from causing symptoms of TB (active disease). In HIV+ people, the bacteria may get out of control, resulting in active disease with symptoms. TB and HIV make each other worse. Worldwide, TB is the leading cause of death in HIV+ people. For more information on TB, please see our article on Tuberculosis.
Pneumonias can be very serious for HIV+ people. However, ongoing medical care allows for the effective prevention or early diagnosis and treatment of pneumonias.