[A contribution to the pathophysiology of post-traumatic brain oedema (author's transl)].

The aim of this paper is to contrast new results obtained on the activities of lysosomal proteases in the brain of traumatized animals with the previously held opinions concerning the development of post-traumatic brain oedema. Two hours after a standardized head injury in the cat, acid and neutral proteases were determined in the brain homogenate. Total as well as free activity, especially of the neutral proteases, were markedly increased after head injury, a circumstance indicating the important role of lysosomes in the development of post-traumatic brain oedema. It is postulated that not hypoxia alone, but primary or secondary disturbance of lysosomal function is the predominant factor in the development of brain oedema. Release of enzymes -- especially proteases -- causes irreversibility of initial vascular oedema by autolysis of cellular structures.