[Changes in the central nervous system in acute viral respiratory infections]

On the basis of a clinico-morphological analysis of 50 cases with acute respiratory viral infections, developing clinically with brain symptoms, the authors distinguish 2 main factors, influencing their development. The main factors consist in a evicious circles of respiratory disorders which causes the appearance of toxico-hypoxic encephalopathy. Encephalitis of an immuno-allergic nature are seen less frequently and may appear soon after acute respiratory viral infections. Histologically there are 2 forms of allergic encephalitis: 1) with perivascular lymphocyte infiltration and 2) hemorrhagical. The second form differs clinically from the first by apoplectic-like development with a coma and rapid short course. Both forms of poctinfluenza allergic encephalitis differ from encephalopathy in the fact that they develop not during the crucial phase of acute respiratory infection, but follow 1-2 weeks. The morphological differences of hemmorrhagical forms of poctinfluenza allergic encephalitis from from encephalopathy are characterized by intensive perivascular hemorrhages with a tendency towards their fusion; by changes in the vascular walls; by an appearance of small foci of colliquative necrosis and demyelinization.