Cerebral Perfusion Pressure in Central Nervous System Infections of Infancy and Childhood

Central nervous system infections may be complicated by development of severe brain edema, which can be a significant factor in mortality and morbidity. Increased intracranial pressure can cause additional damage to the central nervous system by impairment of cerebral blood flow, which is dependent on cerebral perfusion pressure. A reduction of cerebral perfusion pressure, caused by elevation of intracranial pressure, may cause cerebral ischemia. We studied cerebral perfusion pressure in 17 patients, ages 45 days to 11 years, with severe central nervous system infections and who were in deep coma. Meningitis was diagnosed in 64.7%, and encephalitis in 29.4%. The patients who survived (64.7%) did not differ significantly from those who died (36.5%) in severity of disease and maximal intracranial pressure during the course of the illness. A striking difference in minimal cerebral perfusion pressure recorded was found between survivors and nonsurvivors: all patients with minimal cerebral perfusion pressure greater than 30 mm Hg survived, whereas those with lower pressure died. In survivors, cerebral perfusion pressure could be maintained adequately by reduction of intracranial pressure, but nonsurvivors developed noncompliance of brain tissue, and cerebral perfusion pressure could not be maintained at levels that ensure adequate cerebral blood flow, resulting in cerebral ischemia and death. Continuous monitoring of mean arterial blood pressure and intracranial pressure in children with severe central nervous system infections will enable rapid diagnosis and initiation of treatment when cerebral perfusion pressure is reduced to critical levels. Such treatment might improve the prognosis.