Urinary N-acetyl-beta-D-glucosaminidase (NAG) in aminoglycoside nephrotoxicity

Urinary N-acetyl-beta-D-glucosaminidase (UNAG) excretion was measured in 37 children before and during the treatment with aminoglycosides at the Department of Pediatrics, Ramathibodi hospital from July 1 to October 31, 1986. There were 20 males and 17 females whose ages ranged from 15 days - 15 years. Twelve were in postoperative status, 11 with respiratory tract disease, 11 with urinary tract disease and 3 in the miscellaneous group. Aminoglycosides were given alone in 11 patients, combined with cloxacillin in 14 and with other antibiotics in 12 patients. The duration of aminoglycoside given ranged from 5-27 days (mean +/- SD = 11.5 +/- 5.5 days). Clinical nephrotoxicity was detected in 12 patients (32.4%), of which 7 were males and 5 were females, 4 were less than 1 year old. It appeared 4-9 days (mean +/- SD = 5.8 +/- 1.6 days) after initiation of the treatment. Variation in age, sex, initial UNAG excretion and antibiotic combination were not associated with increased risk of nephrotoxicity. Thirty patients had elevated baseline UNAG excretion from 1-14 times higher than the normal value. UNAG excretion was increased 0.23-5.57 fold in all patients after 24 hours of treatment. In those with clinical nephrotoxicity, the enzymuria rose more than one fold in all of them (sensitivity 100%, specificity 68%, accuracy 78.4%) and this was detected 2-7 days (mean +/- SD = 3.8 +/- 1.6 days) prior to the rise of serum creatinine.(ABSTRACT TRUNCATED AT 250 WORDS)