Pneumonia - Risk Factors

Highlights	Risk Factors	Prevention
Introduction	Diagnosis	Resources
Causes	Treatment	References
Symptoms	Medications
Prognosis	Surgery

Risk Factors

Risk factors for pneumonia often depend on the specific type of disease.

Risk Factors for Community-Acquired Pneumonia (CAP)

CAP is the most common type of pneumonia. Itdevelops outside of the hospital. Each year between two and four million people in the US develop CAP, and 600,000 people are hospitalized. The elderly, infants, and young children are at greatest risk for the disease.

Risk Factors for Hospital-Acquired (Nosocomial) Pneumonia

Pneumonia that is contracted in the hospital is called hospital-acquired or nosocomial pneumonia. Itaffects an estimated5 to 10 out of every 1,000 hospitalized patients every year.

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Certain individuals, such as the elderly, the very young, and those with chronic or severe medical conditions, areat higher risk.

In addition, the following conditions within the hospital put patients at higher risk:

Surgery, particularly in people over the age of 80. Among the surgical procedures that pose a particular risk are splenectomy (removal of the spleen), abdominal aortic aneurysm repair, or operations that impair coughing.
Being in the intensive care unit (ICU). This is particularly true for newborns or patients on breathing machines (mechanical ventilators). In one study, 10% ofICU patients on a breathing machinedeveloped pneumonia.Such patients who lie flat on their backs are at particular risk for aspiration pneumonia. Raising the patient up may reduce this risk.
Sedation. Hospital patients who receive sedatives also have a higher risk of developing nosocomial pneumonia.

Hospitalized patients are particularly vulnerable to gram-negative bacteria and staphylococci, which can be particularly dangerous in people who are already ill.

Medical Conditions that Pose Risks for Pneumonia

Chronic Lung Disease. Chronic obstructive lung diseases, including chronic bronchitis and emphysema, affect 15 million people in the U.S. This condition is a major risk factor for pneumonia.

Bronchitis is the inflammation of the bronchi, the main air passages to the lungs. It generally follows a viral respiratory infection. Symptoms include coughing, shortness of breath, wheezing, and fatigue.

Click the icon to see an image of emphysema.

People With Compromised Immune Systems. People with impaired immune systems are extremely susceptible to pneumonia. In addition to AIDS, other conditions that compromise the immune system include organ transplantation, chemotherapy, and cancers, especially leukemia and Hodgkin's disease. Patients who are on corticosteroids or other medications that suppress the immune system are also prone to infection.