Introduction

The term “kernicterus” was originally used to describe the deposition of bilirubin in the basal ganglia. It was first described in 1903 by Schmorl. More recently, the term has also been used in reference to the neurological manifestations of hyperbilirubinemia. Another acronym, BIND, has been adopted to describe any bilirubin-induced neurologic dysfunction. Although technically the diagnosis of kernicterus can only be confirmed at autopsy, brain magnetic resonance imaging (MRI) studies may now aid in the confirmation of the diagnosis in a living child with severe jaundice. The MRI signature for kernicterus includes high signal intensity on T1-weighted (T1W) images in the globus pallidus (GP), internal capsule, thalamus, and hippocampi. The associated T2W images have abnormal increased signal in the GP and thalamus in the same regions as the high signal on the T1W images. Loss of demarcation between GP, internal capsule, and the anterior thalamus was the major finding (Figures 27.1 and 27.2). The source of these abnormal signals has not been definitively identified and therefore, the MRI findings should not be considered diagnostic in themselves, but only consistent with the diagnosis of kernicterus in the context of severe neonatal jaundice and the acute clinical features of kernicterus (Table 27.1).

Neonatal jaundice and neurotoxicity

Most often a benign condition, a majority of term neonates develop neonatal jaundice which is a consequence consequence of relatively increased bilirubin production (two- to threefold higher in a neonate compared to an adult) and limited ability to conjugate bilirubin in the transitional time after birth.