However, regardless of whether transudative or exudative, large, refractory pleural effusions causing severe respiratory symptoms can be drained to provide symptomatic relief. The management of exudative effusions depends on the underlying etiology of the effusion. Pneumonia, malignancy, and TB cause most exudative pleural effusions, with the remainder typically deemed idiopathic. Complicated parapneumonic effusions and empyemas should be drained to prevent development of fibrosing pleuritis.
Retrograde amnesia is inability to recall memories before onset of amnesia. One may be able to encode new memories after the incident. Retrograde is usually caused by head trauma or brain damage to parts of the brain besides the hippocampus. The hippocampus is responsible for encoding new memory.
If the amnesia is thought to be of psychological origin, it is termed psychogenic. Memory loss may result from bilateral damage to the limbic system of the brain responsible for memory storage, processing, and recall.(Illustration by Electronic Illustrators Group). Retrograde. 2  In some ways, this form of amnesia is the opposite of anterograde amnesia: the victim can recall events that occurred after a trauma, but cannot remember previously familiar information or the events preceding the trauma.