The effect of phenobarbital on the accuracy of technetium-99m diisopropyl iminodiacetic acid hepatobiliary scintigraphy in differentiating biliary atresia from neonatal hepatitis syndrome.

Biliary atresia (BA) and neonatal hepatitis syndrome (NHS) are major causes of cholestatic jaundice in infancy. Technetium-99m diisopropyl iminodiacetic acid hepatobiliary scintigraphy (99mTc-DISIDA scan) is widely used in the differentiation of these two entities. The objective of this study was to evaluate the effect of phenobarbital premedication on the accuracy of 99mTc-DISIDA scan. Ninety-five cholestatic infants (38 females and 57 males) with an age range of 2 weeks to 4 months (mean 2.1 mo) who underwent 99mTc-DISIDA scan testing were retrospectively reviewed. The patients were divided into 3 groups according to the history of phenobarbital administration prior to 99mTc-DISIDA scan examination. Group 1 (n = 48), group 2 (n = 29), and group 3 (n = 18) received phenobarbital at the dosage of 5 mg/kg/day for at least 5 days, less than 5 mg/kg/day or less than 5 days, and no premedication, respectively. The accuracy of 99mTc-DISIDA scan in differentiating BA from NHS in group 1, 2, and 3 was 72.92 per cent, 89.66 per cent, and 100 per cent, respectively. No significant difference was seen between the patients who received and did not receive phenobarbital in terms of age at presentation, age at onset of jaundice, and liver function tests. In conclusion, phenobarbital therapy may not be necessary prior to 99mTc-DISIDA scan examination in the evaluation of cholestatic infants and thus a delay in diagnosis and surgical therapy of BA can be avoided.