Pneumonia is a serious infection of one or both lungs in which fluid and damaged lung cells fill the air spaces in the lungs, making it difficult to breathe. Pneumonia can be caused by a viral, bacterial, fungal or Mycoplasma infection, but can also be caused by anything that obstructs the bronchial tubes such as a tumor, or inhaled objects like peanuts or small toys. These obstructions can trap bacteria, viruses, or fungi, causing pneumonia. The offending organisms trigger a significant inflammatory defense response. Bacterial pneumonias are usually associated with clogging of airways and air chambers by acute inflammatory cells, while viral infections are generally associated with invasion of the walls of the alveoli by a different type of inflammatory cells and these cause the so called interstitial (in between tissue) pneumonia.

The severity of pneumonia depends on a number of factors including how dangerous is the infecting organism, the amount of exposure and your general health. Having the flu may make it easier for other organisms to infect the lungs.

Symptoms begin about 15-25 days after being exposed to an infected person, and develop gradually over the course of 2-4 days. Typical symptoms may include fever, shortness of breath, severe shaking chills, excessive sweating, sore throat, a cough that may or may not produce mucus, malaise and occasional chest pain. Symptoms may persist for a few days to more than a month. As pneumonia progresses breathing becomes rapid, shallow and painful, the heart rate increases, and the skin may turn bluish in color.

Mycoplasma
Walking or atypical pneumonias are pneumonias that are caused by less common microorganisms, and most of them are caused by Mycoplasma, an extremely tiny microscopic organism related to bacteria.

Mycoplasma pneumonia affects primarily adults below 40 years of age and children. Mycoplasma infections occur year round but are more common in late summer and fall. Mycoplasma pneumonia is infectious and is spread through contact with droplets expelled from the nose and throat of affected people when they sneeze or cough.

Generally the transmission of the disease requires a relatively prolonged close contact with an infected person, and most transmissions occur within families. However, every 4 to 8 years, Mycoplasma pneumonia epidemics may occur and involve as many as 50% of all pneumonias.

Occasionally, the Mycoplasma pneumonia may be associated with a painful ear infection, anemia or skin rashes. The disease is usually relatively mild, but occasionally individual symptoms may be quite distressing with the patients feeling generally much worse than they look. Diagnostic tests may reveal increased concentrations of certain immune substances (cold agglutininns) but a definite diagnosis of Mycoplasma infection, requires more complicated serological tests which are not usually done unless they are part of a research protocol or for diagnostic purposes of suspected epidemics.

Immunity after mycoplasma infections does occur but it is not life long and its exact duration is unknown. Recurrent infections are usually much milder than the original episode.

Currently there are no vaccines for the prevention of Mycoplasma infection and the only way of averting the associated walking pneumonia is to avoid being exposed to the sneezing or coughing of infected patients. An untreated Mycoplasma pneumonia, in most cases will resolve spontaneously, but may easily drag on over a couple of months or more.