The biliary tree includes the ducts that drain bile from the liver and coalesce into the right and left hepatic ducts, the cystic duct and gallbladder, and the common bile duct that drains bile from the gallbladder through the pancreas and into the duodenum. Biliary tract diseases can present at any age and have become increasingly recognized in pediatric practice as diagnostic tests have improved. Some diseases of the biliary system are associated with liver disease and others are specific to the biliary tract alone. In addition, some biliary diseases present at specific ages in children while others can develop at any time from early infancy through adulthood.
The primary pathologic processes of biliary tract disease fall into two categories, obstructive or inflammatory. Obstruction diminishes flow of bile from the liver into the duodenum with resultant pressure in the biliary system (leading to pain, jaundice, and potentially pancreatitis), fat malabsorption (from poor micelle formation in the gut), and potential infection (from gut flora contamination of the static bile fluid in the biliary tree). Hepatic inflammation and damage may result if biliary obstruction or inflammation is not relieved or treated.
Obstruction is most often from gallstones but may also occur as a result of anatomic abnormalities or scar formation. Chronic inflammation of the biliary tree, whether in the large ducts draining the liver and gallbladder or in the small ducts within the liver, can lead to scarring and obstruction of bile flow. Inflammatory processes are most often autoimmune in nature but can be due to chronic infections or genetic diseases. They are often insidious and unrecognized until significant biliary damage has occurred and large duct obstruction develops. Finally, the gallbladder itself can be poorly functional in storing and/or evacuating bile, which can lead to more subtle, subacute reductions in bile flow and chronic pain from gallbladder distention and inflammation.
Jaundice is the primary sign of biliary disease, indicating significant obstruction to bile flow. Jaundice typically prompts medical evaluation that leads to the diagnosis of biliary disease. Complete or near-complete obstruction of bile flow can result in acholic stools that are light yellow to clay in color. For infants in diapers, stools may occasionally have a hint of pigment on the exterior surface due to sloughing of enteric cells or staining from bile-pigmented urine. Once this layer is removed, however, the clay-colored stool inside is apparent.1
Careful attention is required when evaluating jaundice in neonates as approximately 60% of term neonates and 80% of preterm infants develop physiologic jaundice in the first days of life.2 This can lead to complacency and delays in diagnosing more serious liver and biliary diseases that present in early infancy. Any infant with new or persistent jaundice beyond the first 2 weeks of life requires further evaluation that includes measurement of fractionated serum bilirubin. ...