Pneumonia remains a major health issue, even with the availability of antibiotics and vaccines. The medical literature includes distinctions between community acquired pneumonia (CAP), ventilator-associated pneumonia (VAP), hospital acquired pneumonia (HAP), and healthcare-associated pneumonia (HCAP).
Dr. E. Polverino of the Hospital Clinic of Barcelona and Dr. A. Torres Marti of the University of Barcelona, Spain, provided a review of community acquired pneumonia, which can strike anyone.
“In the United States, CAP is the sixth leading cause of death,” Polverino and Torres reported. Each year, 4 million adults are infected, and 1 million are hospitalized. Documented risk factors include the following:
1. Age. Individuals over age 65 are at higher risk.
2. Alcohol consumption. Alcohol has immunosuppressive effects that persist for several months after the last drink. In addition, alcohol's changes to consciousness increase the risk of aspiration pneumonia.
3. Smoking. Tobacco smoke alters muco-ciliary transport, and humoral and cellular defense.
4. Chronic illnesses. Chronic obstructive pulmonary disease (COPD), congestive heart failure, chronic kidney or liver disease, cancer, diabetes, dementia, cerebrovascular diseases, and immunodeficiency diseases are all associated with higher pneumonia risk.
5. Asplenia (loss of spleen function). This can be caused by rare genetic defects or damage to the immune system.
6. Immuno-compromising medications. These are used to treat inflammatory and autoimmune conditions, as well as to prevent organ transplant rejection.
7. Residence in long-term care facilities.
Diagnosis is based on respiratory symptoms, lab tests, and X-ray. Polverino and Marti explained, “the gold standard for diagnosis is the presence of new pulmonary infiltrates, as observed by X-ray, in combination with compatible clinical symptoms, and laboratory and microbiological findings.” However, up to 31 percent of pneumonia cases may not show up on X-ray images.
Pneumonia can be caused by many different bacteria and viruses. Rarely, fungi or parasites can also cause pneumonia. Two or more pathogens can infect the lungs at the same time, even in otherwise healthy people. This happens in 5 to 25 percent of patients. Lab tests are necessary to identify the pathogen(s), since the symptoms are the same for different causes of pneumonia.
Treatment depends on the cause. Antibiotics are effective against bacterial pneumonia. Antiviral drugs are available for pneumonia caused by the influenza virus, but not for cases caused by other viruses.
Beyond antimicrobial drugs, other potential therapies include drugs aimed at modulating the inflammatory response. Dr. S. C. A. Meijvis and colleagues in The Netherlands provided a review. Corticosteroids, activated protein C, statins, and intravenous immunoglobulins are under investigation as supportive therapy for pneumonia.
References:
Polverino E, Marti AT, “Community-acquired pneumonia”, Minerva Anestesiol 2011; 77: 196-211.
http://www.ncbi.nlm.nih.gov/pubmed/21242952
Meijvis SCA et al, “Therapy in pneumonia: what is beyond antibiotics?”, Netherlands Journal of Medicine 2011; 69(1): 21-6. http://www.ncbi.nlm.nih.gov/pubmed/21325697
Linda Fugate is a scientist and writer in Austin, Texas. She has a Ph.D. in Physics and an M.S. in Macromolecular Science and Engineering. Her background includes academic and industrial research in materials science. She currently writes song lyrics and health articles.
Reviewed November 17, 2011
by Michele Blacksberg RN
Edited by Jody Smith