[Brain thermo-pooling is the major problem in pediatric influenza encephalitis]

The prognosis of pediatric encephalitides, such as infantile influenza encephalitis, is still poor because of the rapid progression, severe brain edema, selective bilateral basal ganglia necrosis, and a poor immune function, the mechanism of which is still unknown. Especially, little is known about virus es in CSF and brain tissue with influenza encephalitis, which hampers successful treatment of this condition. Recently, hypothermia treatment has attracted attention as the management of infantile influenza encephalitis to prevent severe brain edema. Recent clinical studies have revealed brain thermo-pooling (elevation of brain tissue temperature) with damage of blood-brain barrier (BBB). We then studied brain injury mechanism after severe brain injuries, cerebral strokes, reperfusion after shock, and high fever with lower cerebral perfusion pressure in our ICU. The brain thermo-pooling phenomenon results from body temperature higher than 38 degrees C, systolic blood temperature lower than 90-100 mmHg, and cerebral perfusion pressure (CPP) lower than 70 mmHg that hinders washout of brain tissue temperature by cerebral blood flow. We have recorded of brain tissue temperature of 40-44 degrees C in various brain injured patients. Some pathophysiological changes in infantile influenza encephalitis may be explained on the basis of this brain thermo-pooling phenomenon. In systemic infection, it causes severe brain edema by activation of cytokines and destruction of BBB, bilateral basal ganglia necrosis by acute severe brain hypoxia, resulting in poor prognosis without control of brain temperature. In other words, brain thermo-pooling, is the major target of treatment for infantile influenza encephalitis. In this paper, new concepts of the brain injury mechanism and methods of brain hypothermia treatment of pediatric influenza encephalitis are presented.