Factors influencing the development of hypertensive encephalopathy in acute glomerulonephritis.

The factors influencing the development of electroencephalographic (EEG) abnormalities and hypertensive encephalopathy were studied in 31 children with acute glomerulonephritis and hypertension. Based on the degree of background slowing on the EEG, they were divided into 2 groups: group 1 had a percent EEG power for frequencies 1-4 Hz of less than or equal to 6.45 (upper 95th percentile confidence limit in 31 age- and sex-matched controls), while group 2 had values greater than 6.45. Six of 16 children in group 2 developed grand mal convulsions and had prolonged changes in the level of consciousness. There were no significant differences between the mean levels of peak blood pressures (systolic, diastolic and mean), degree of fluid overload, and fractional sodium excretion in the 2 groups. However, group 2 had significantly higher mean blood urea and creatinine levels (p less than 0.02 and p less than 0.03 respectively). These findings suggest that hypertension alone does not predict the subsequent development of EEG abnormalities and hypertensive encephalopathy. The concomitant presence of azotaemia may render the child more susceptible to cerebral autoregulatory dysfunction, resulting in hypertensive encephalopathy.