Atypical Pneumonia Causes

Atypical pneumonia caused by Mycoplasma and Chlamydophila usually result in milder forms of pneumonia and are typified by a more drawn out course of symptoms unlike other forms, which come on quicker and with more severe early symptoms.

Younger people are more likely to be affected by mycoplasma pneumonia and may develop symptoms outside of the lungs (eg anemia and rashes), and neurological syndromes (such as meningitis, myelitis and encephalitis). However, more severe forms of pneumonia have been found to affect all age groups.

Occuring all year round, Chlamdophila pneumonia accounts for 5-15% of all pneumonias. It is a mild form and with a low mortality rate. On the other hand, atypical pneumonia due to Legionella has a higher mortality rate and accounts for 2-6% of all pneumonias.

Those falling in the high risk category for this kind of pneumonia are elderly individuals, smokers, people with weakened immune systems and those with chronic illness. Contact with contaminated aerosol systems (eg infected air conditioning) is also responsible for causing pneumonia due to Legionella.

Factors that could be responsible to increase the risk of atypical pneumonia in infants include :

• Young maternal age.

• Low socio-economic status.

• Multiple maternal sex partners.

• Exposure to other children at home or in day care.

• Exposure to passive smoking.

• Unmarried maternal status.

A wide range of respiratory infections including tracheobronchitis, pneumonia and upper respiratory tract infections are caused by mycoplasma pneumonia. It has been observed that only 3 to 10 percent of persons affected with mycoplasma pneumonia develop pneumonia. As atypical pneumonia becomes more common with advancing age, it is important to ascertain and diagnose this infection in elderly patients.

Atypical pneumoniae infection occurs throughout the year but can cause periodic outbreaks within small communities. Transmission is by person-to-person contact, and infection spreads slowly, most often within closed populations (e.g., households, schools, businesses).

The normal clinical course of pneumonia due to mycoplasma pneumoniae is mild and self contained. The mortality rate is about 1.4%. However significant pulmonary complications like effusion, empyema, pneumothrax and respiratory distress syndrome could develop.

Atypical pneumonia could also result in several extrapulmonary ailments. Some skin infections thus caused include erythema multiforme, erythema nodosum, maculopapular and vesicular eruptions, and urticaria. Neurologic derangements like aseptic meningitis, cerebral ataxia, Guillain Barre syndrome, encephalitis and transverse myelitis. When mycoplasma pneomoniae titers are high, the production of cold agglutinins can result in hemolytic anemia. Further complications like myocarditis, periicarditis, pancreatitis and polyarthritis can also develop.