This review outlines the basic concepts and pathophysiological aspects of the chemistry of free radicals in all forms of brain injury and brain edema. Brain edema, defined as an abnormal accumulation of fluid associated with volumetric enlargement of the brain, is complicated and multifactorial, and it is still a serious complication of strokes, brain tumors, brain abscesses and hypoxic injury. Recent experimental studies have demonstrated that free radicals play an important role as chemical mediators in causing brain edema and brain damage. Pharmacological antagonism of free radicals with free radical scavengers shows beneficial therapeutic results. Future research into brain edema and optimal combinations of therapeutic regimens is expected to improve the management of patients with brain edema.
Congenital ureteropelvic junction obstruction (UPJO) is one of the most common causes of hydronephrosis in children. We report on 2 patients with severe hydronephrosis detected prenatally who did not develop obstructive nephropathy after birth. The pathogenesis of the dilation in both patients was UPJO. Although much controversy still surrounds the clinical significance of antenatal hydronephrosis and the management of patients, our follow-up for these 2 patients consisted just of serial blood tests, urine tests and technetium-99m-labeled dimercaptosuccinic acid renal scintigraphy (DMSA). Patient 1 had bilateral hydronephrosis, and the renal uptake of DMSA in the right kidney was severely decreased. Therefore, we performed a right percutaneous nephrostomy and observed the left kidney conservatively. By the time the patient was 18 months old, the hydronephrosis of the left kidney had developed considerably, with the kidney reaching into the pelvic cavity; however, there was no decrease in the renal uptake of the kidney. Hydronephrosis was also detected prenatally in the right kidney of Patient 2, but the left kidney was morphologically and functionally normal. At the age of 8 months, the patient developed acute focal bacterial nephritis (FBN) in the right kidney, with decreased renal uptake. There was no subsequent decrease in renal uptake, but the hydronephrosis worsened, and the kidney increased drastically in size. Some researchers recommend early surgical intervention in cases of severe UPJO to achieve early relief from obstruction. However, as shown in this report, some patients show no degeneration of kidney function in spite of worsening hydronephrosis. Careful consideration of the risks associated with general anesthesia and surgery are needed before deciding on treatment.