Feeling terrible, with painful cough and fever? Sorry -- it still may not be pneumonia . . . yet!
To earn that diagnosis you need an X-ray showing a fluffy infiltrate inside your chest -- an indication that infection has gone beyond the airways and now involves the tender pillow-like tissues of your lungs. At this stage the infection interferes with the oxygen-exchanging function of your pulmonary system, and can rapidly turn into a life-threatening illness.
Of course once you have pneumonia, you need to worry about what kind. Viral, caused by influenza, cytomegalovirus or respiratory syncytial virus -- fungal, such as histoplasmosis or coccidioidomycosis -- or bacterial, a whole rogue's gallery of grim reapers with names like pneumococcus, klebsiella, staphlococcus and others that can be hard to treat and even harder to pronounce.
Fortunately, since the discovery of penicillin, drug companies have earned billions developing cures for most of these infections, and a happy outcome is common. New vaccines offer extra protection, and in fact, lots of pneumonia patients don't even get admitted into the hospital nowadays, leaving them to cough and grumble with unsympathetic spouse and neighbors.
The good news -- having pneumonia is a great way to quit smoking! Also, since the lung findings take time to clear up, you can take consolation that proof of your illness will linger on your X-rays for a few weeks.