Later changes in brain death. Signs of partial recirculation.

The varying cell picture of the brain in brain death is impressive. Some authors have interpreted this cell picture as a result of intravital autolysis and others as necrosis, at which the maturation time obviously plays an important part. The following time-dependent cerebral changes were established on the basis of an evaluation of 190 brain death cases: (1) neuronal necroses that arise at different rates within the cerebral cortex and the lower brain stem; (2) a hemorrhagic-meningoencephalitic reaction that occurs exclusively at least 4 days after brain death or hemorrhages alone after intervals of at least 48 h; and (3) a washed-out tissue picture. The alterations in the spinal border zone of the total infarction, like in the brain itself, increase rapidly after 48 h. The regular onset of inflammatory alterations after long brain death intervals can only be explained by partial recirculation due to a decline of the high intracranial pressure. The hemorrhages and increasing necroses in some cases with longer intervals therefore are likewise evidence of a not entirely complete cerebral ischemia in spite of an angiographically demonstrable circulatory arrest.