What is the difference between classical/typical pneumonia and atypical pneumonia?
Usually the atypical causes also involve atypical symptoms:
- No responding on common antibiotics as sulfonamide and beta-lactams like penicillin.
- No signs and symptoms of lobar consolidation, meaning that the affection is restricted to small areas, rather than involving a whole lobe. As the disease progresses, however, the look can tend to lobar pneumonia.
- Absence of leukocytosis.
- Extrapulmonary symptoms, related to the causing organism.
- Despite general symptoms and problems with the upper respiratory tract like high fever, headache, a dry irritating cough, later a productive cough and radiographs, showing consolidation, there are in general few physical signs. The patient looks worse than the symptoms suggest.
Classical/typical pneumonia is mainly caused by bacteria such as streptococcus. Atypical pneumonia is mainly caused by viruses such as influenza and adenovirus, bacteria such as chlamydia and mycoplasma, and other unknown agents.