Hypertensive encephalopathy following urological surgery.

A 14-month-old male was admitted to hospital with a 2-day history of irritability, vomiting and pyrcxia (4O.5°Q. He had not voided urine in the previous 24 hours. On examination he was extremely irritable and dehydrated (weight 8.8 kg), with obvious abdominal distension. His temperature was 37.5°C, the pulse rate was 150/min and the arterial systolic blood pressure was 150 mm Hg measured with a sphygmomanometer and palpatation of the radial artery. The bladder was palpable 3 cm above the umbilicus. Laboratory data included: blood urea nitrogen 64 mg%; blood creatinine 4.2 mg%; serum sodium 137 m.equiv/1.; potassium 5.7 m.equiv/1.; chloride 101 m.equiv/1. Preoperative therapy and evaluation included suprapubic catheterization, kanamycin and ampicillin therapy for urinary tract infection and possible septicaemia, and hydration. Intravenous pyelography showed massive bilateral hydro-uretero-nephrosis, probably the result of a lower urinary tract obstruction. The presence of posterior urethral valves was confirmed later. Throughout the praoperative period the arterial systolic pressure was approximately 150 mm Hg. Thirty-six hours after admission bilateral pyelostomies were performed. Pentobarbitone 30 mg and atropine 0.15 mg were administered by intramuscular injection 40 minutes before the induction of anaesthesia. Halothane, nitrous oxide and oxygen were administered first from a face mask and later through an endotracheal tube. The operation lasted 1 hr 40 min, dining which the patient was in the prone position. Systolic arterial pressure measured with a percutaneous Doppler apparatus was remarkably stable throughout and ranged from 106 mm Hg to 110 mm Hg. The arterial pressure remained stable at 130/86 mm Hg in the first 30 min of the recovery period. The child regained consciousness rapidly, cried and moved vigorously. Over the next 70 min the arterial pressure increased sharply (fig. 1) to over 300 mm Hg systolic and 200 mm Hg diastolic and he became unconscious. Reserpine 0.3 mg i.m. and hydralazine 1.5 mg Lv. were given (fig. 1, point A). Within 30 min the arterial pressure decreased to 180/110 mm Hg. A further 0.5 mg of hydralazine i.v. (fig. 1, point B) resulted in a further decrease in arterial pressure to 130/80 mm Hg. As the blood pressure decreased, the child regained consciousness. During the next 8 days the patient's arterial pressure gradually returned to normal and on periodic follow-up examinations it has remained approximately 90/60 mm Hg without medication.