If you're young and healthy, pneumonia typically means rest and antibiotics at home. Another way is when the infection spreads to the bloodstream, a condition called bacteremia. Sometimes, this can happen in less than 48 hours. Pneumonia can be tricky. It can mimic a cold or the flu and then turn out to be something worse.
Symptoms vary, depending on what type of organism is causing the infection.
Older adults or those with underlying disease may have less specific symptoms. Viral pneumonia can be caused by the influenza virus or other viruses. It tends to be more serious in people with heart or lung disease. Viral pneumonia, which strikes primarily in the fall and winter, typically starts as a dry cough, headache, fever, muscle pain and fatigue. As the pneumonia advances, symptoms can progress to a cough that produces phlegm and breathlessness.