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.
1 Retrograde amnesia is the case where, following a trauma, the patient is unable to recall important memories and information from before that event.2  The recent Hollywood movie, While You Were Sleeping, depicts a lawyer whose injury makes it difficult to recall events from before his accident.mnesia is most commonly associated with either brain damage through injury or degeneration of brain cells in dementia. In both cases, brain cells are lost, and due to the complex network connecting cells within the human brain, they cannot be replaced.