Pneumonia Make an Appointment Find a Doctor Ask a Question Reviewed by Wendi Drummond, DO (August 01, 2017) What Is Pneumonia? Pneumonia is an infection of the lungs. Many different organisms cause pneumonia. Most community-acquired pneumonias are caused by common bacteria and viruses. Pneumonia caused by more unusual organisms can occur, depending on a person’s exposure and other underlying medical illnesses. Pneumonia is often acquired by inhaling infected particles or by aspiration ("swallowing" into the lungs). This means that fluids can be introduced into the lungs when you swallow or if you have severe reflux from the esophagus in which the stomach contents can be introduced into the airways. Bacteria can occasionally spread through the bloodstream to infect other parts of the body. Some people may be at a higher risk of developing pneumonia. These include people with chronic heart or lung disease, diabetes, immune suppression (which can occur with long term or high dose steroid use or if you are on other immune suppressive medications), the elderly and people with alcoholism. How Long Does Pneumonia Last? Pneumonia can last a short or long time. Its length depends upon the organism involved, the general health of the person, and how promptly a person gets medical care. Some people may be hospitalized, while others continue their routine without being aware that they are infected. Certain people may have to limit their work or school schedule for a short time. Your health care provider can help you define any limits on work or other activities. It is important to remember that infection (especially from viruses) may lead to a cough that lasts for 6 – 8 weeks after the infection clears. You may want to talk with your health care provider about how long your symptoms may last. Are There Complications from Pneumonia? Complications from pneumonia may occur. Bacterial infections may follow viral pneumonia. This may require that antibiotics be added or altered to treat the new organism. Rarely, a lung abscess may result from pneumonia. If excess fluid builds up in the sac around the lungs (pleural effusion), it may need to be drained. Low blood sodium (hyponatremia) can also be a complication of bacterial pneumonia. Children are prone to this. In these cases, a person may need to be hospitalized for IV (intravenous) fluids. A bloodstream infection, septic shock and respiratory failure requiring admission to an intensive care unit can occur in the most severe cases. Many complications from pneumonia can be prevented by prompt medical care. Programs & Services Deployment-Related Lung Disease Center Respiratory Treatment Programs Clinical Trials For more than 100 years, National Jewish Health has been committed to finding new treatments and cures for diseases. Search our clinical trials.