What is the difference between pneumonia and pulmonary edema?

Infection vs Fluid: Accumulation. Pneumonia means you have an infection in your lungs. Where as pulmonary edema reflects fluid accumulation in your lungs.

Fluid versus infect: Pulmonary edema is fluid in the lung from any cause, sometimes related to impaired heart function, but also seen with a number of other causes of inflammation in the lung, such as smoke inhalation, trauma, and severe infections including pneumonia. Pneumonia is a lung infection. The two entities can coexist and may look similar on chest xray.