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. 1  Retrograde motion, in astronomy, describes the orbit of a celestial body that runs counter to the direction of the spin of that body which it orbits. 2  Apparent retrograde motion, in astronomy, is the apparent motion of planets as observed from a particular vantage point.