Atypical pneumonia is a term used to describe a form of pneumonia not caused by one of the more traditional pathogens. The term "atypical" is used because atypical bacteria commonly affect healthier people, cause generally less severe pneumonia, and respond to different antibiotics than other bacteria.
It can caused by one or a combination of the following organisms:Legionella pneumophila
: Causes a severe form of pneumonia with a relatively high mortality rate, known as legionellosis
or Legionnaires' disease.Mycoplasma pneumoniae
: Usually occurs in younger age groups and may be associated with neurological and systemic (e.g. rashes) symptoms.Chlamydophila pneumoniae
: Mild form of pneumonia with relatively mild symptoms.
The severe acute respiratory syndrome (SARS) was also considered a kind of atypical pneumonia, and is still called so in the Chinese mainland.
Symptoms include fever
, shortness of breath, laboured breathing, cough
and potentially cough fractures
(joint pain), malaise, loss of appetite
, confusion, rash, and diarrhea
Treatment is with oral antibiotics
, mainly with those which interfere with protein synthesis e.g. erythromycin
, and diagnosis is confirmed by blood
cultures and sputum
Prognosis is usually good and is influenced by age