What is the difference between pulmonary edema and pulmonary congestion?

Pulm edema: A matter of semantics to some physicians. The terms are often used interchangeably to describe fluid build-up in the lungs regardless of cause. More descriptive terms that are used include cardiogenic pulmonary edema and non-cardiogenic pulmonary edema.

Not much: Pulmonary edema is a type of pulmonary congestion. Congestion just means something is in your lungs. Pulmonary edema means that "water" is in your lungs usually from the heart not pumping well.