Question: what is atypical pneumonia really?

Less common germs. The "typical" are caused by certain bacteria such as streptococcus, and hemophilus...Atypicals included mycoplasma, chlamydia and are treated differently because the cause is different.
Atypical PNA. Atypical pneumonia, otherwise known as walking pneumonia, is a type of pneumonia caused by certain bacteria that generally cause a milder and longer lasting type of pneumonia. Often overlooked because the symptoms are so mild. Could cause cough, shortness of breath, chills, sweats, fever, chest discomfort.