Community-acquired pneumonia (CAP)  is a common illness and can affect people of all ages. CAP occurs throughout the world and is a leading cause of illness and death.

Some causes of CAP include bacteria, viruses, parasites and fungi. Symptoms of CAP commonly include: problem breathing, coughing that produces greenish or yellow sputum, high fever that may be accompanied with sweating, chills, sharp or stabbing chest pain and also rapid and shallow breathing that is often painful.

Individuals with symptoms of CAP require further evaluation. Phsysical examination may reveal fever, an increased respiratory rate, low blow pressure, a fast heart rate, and/or changes in the amount of oxygen in the blood.

X-ray of the chest, examination of the blood and sputum for infectious microorganisms and blood tests are commonly used to diagnose individuals with suspected CAP based upon symptoms and physical examination. Increased vibration of the chest when speaking  and increased volume of whispered speech during auscultation of the chest can also reveal consolidation.

Bacteria and fungi also typically enter the lung with inhalation, though they can reach the lung through the bloodstream if other parts of the body are infected. Often, bacteria live in parts of the upper respiratory tract and are constantly being inhaled into the alveoli. Once inside the alveoli, bacteria and fungi travel into the spaces between the cells and also between adjacent alveoli through connecting pores. This invasion triggers the immune system to respond by sending white blood cells responsible for attacking microorganisms  to the lungs.

In general, all therapies in older children and adults will include treatment for atypical bacteria. Typically this is a macrolide antibiotic such as clarithromycin or azithromycin although a fluoroquinolone such as levofloxacin can substitute.