Definition:

brain congestion

Increased volume of the intravascular compartment of the brain; often associated with brain swelling.

Synonym: encephalaemia.

and another:

Congestion (Cong. of Lungs/ Congestion of Brain/ Congestion of Liver/ Conjestion) - Overfullness of the capillary and other blood vessels, etc., in any locality or organ (often producing other morbid symptoms); local hyperaemia, as, arterial congestion, venous congestion, congestion of the lung

Jim Martin