Of the common causes for exudative pleural effusions, parapneumonic effusions have the highest diagnostic priority. Even in the face of antibiotic therapy, infected pleural effusions can rapidly coagulate and organize to form fibrous peels that might require surgical decortication.
Retrogradation is the landward change in position of the front of a river delta with time.etrogradation is the landward change in position of the front of a river delta with time.
Retrograde motion is the apparent motion of a planet to move in a direction opposite to that of other bodies within its system, as observed from a particular vantage point. Direct motion or prograde motion is motion in the same direction as other bodies.