Imaging of the jaundiced child

Abstract

•. In infants and older children ultrasound remains the initial radiological investigation and further imaging is dependent upon the sonographic findings. •. Advances in MRI technique in the evaluation of the biliary tract in children avoids more invasive investigations. •. Imaging primarily aims to differentiate extrahepatic from intrahepatic causes. •. Any neonate with jaundice persisting beyond 2 weeks warrants investigation to exclude biliary atresia as diagnosis prior to 8-weeks-old achieves the best long term surgical success. •. Gallstones are increasingly prevalent in older children but underlying choledochal cysts should be sought when bile duct stones are found. •. Hepatic and pancreatic masses are a rare but important differential in the investigation of jaundice and require evaluation by CT or MRI. This article outlines a practical approach to the investigation of the jaundiced child and reviews the imaging modalities and findings that can establish a diagnosis or narrow the differential. A systematic approach to the work-up of the jaundiced child prevents unnecessary tests and facilitates prompt treatment. Imaging of the jaundiced neonate and infant is reviewed separately to that of the older child and adolescent owing to different aetiologies in the two age groups. There are wide and varied differential diagnoses for the cause of jaundice in a child, which are broadly classified as pre-hepatic, hepatic and post-hepatic. Imaging does not play a significant role in elucidating the cause of pre-hepatic (unconjugated hyperbilirubinaemia); the underlying causes include physiological jaundice, breast milk jaundice, haemolysis and sepsis. Imaging does, however, play an important role in the investigation of conjugated hyperbilirubinaemia, which nearly always reflects hepatic dysfunction. One of the major roles of imaging is to differentiate intrahepatic from extrahepatic causes of jaundice although the underlying diagnosis is often ultimately established by a combination of clinical presentation and findings, laboratory tests, imaging and histology. Initial laboratory tests include liver function tests (including conjugated bilirubin fraction), hepatitis screening, TORCH (Toxoplasmosis, Other (syphilis, hepatitis, zoster), Rubella, Cytomegalovirus and Herpes) titres, a sepsis screen (blood, urine and cerebrospinal fluid (CSF)), metabolic screen (e.g. alpha1-antitrypsin phenotype testing) and sweat test, and in older children a toxic screen and autoantibodies. These results help to determine the most appropriate imaging.