Risk factors for brain abscess in patients with congenital cyanotic heart disease.

Brain abscess is a serious complication of congenital cyanotic heart disease. We retrospectively evaluated the risk factors for brain abscess in 21 such patients treated between 1975 and 1990 in comparison with a control group. The mean arterial oxygen saturation, arterial partial pressure of O2, arterial blood oxygen content, and base excess in patients with brain abscess were significantly lower than in the control patients. The mean arterial partial pressure of CO2, pH, hematocrit, hemoglobin, and red blood cell content in patients with brain abscess were not significantly different. Patients with congenital cyanotic heart disease may develop minute encephalomalacia due to severe hypoxemia and increased blood viscosity resulting from compensatory polycythemia. The increased blood viscosity and reduced blood flow in the microcirculation may induce cerebral thrombosis or exaggerate minute encephalomalacia during dehydration or cardiac dysfunction, and shunted blood containing infectious organisms at such sites may be followed by focal cerebritis.