Biliary Atresia Screening
Infant Stool Colour Card allows parents to screen for Biliary Atresia
Biliary Atresia (BA) is a rare but serious liver disease that begins to affect newborns in the first month of life. BA is the leading cause of cholestasis in the newborn, is the most frequent indication for liver transplant in the pediatric population and is the most common cause of liver related death in children. Early identification of this disease and early intervention is key to better outcomes, making it an ideal target for newborn screening.
In November, the Newborn Screening Ontario (NSO) is launching a new screening program that will provide parents with a tool to use at home to help them identify when something might be wrong with their baby and instruct them how to take immediate action. This will be the first parent-led screen coordinated by NSO.
BA is a uniquely pediatric liver disease with an estimated incidence of 1 in 19,000 live births in Canada and 1 in 16,600 live births in Ontario. The etiology of BA is unknown, but it is believed that there are several different mechanisms involved, leading to differential timing of the onset of clinical signs and symptoms.
Infants with BA experience a progressive obliteration of the ducts draining bile from the liver to the intestine. Most newborns with BA appear healthy at birth but will develop conjugated hyperbilirubinemia, dark urine, and acholic stools by approximately 2-4 weeks of age. In the early stages of the disease, the most common sign is asymptomatic jaundice, which may be incorrectly attributed to physiologic or breastfeeding jaundice, leading to a delay in diagnosis of BA. Ascites, hepatosplenomegaly, and GI bleeding resulting from portal hypertension are late findings, as is failure to thrive, irreversible liver cirrhosis, and eventual death if surgery or liver transplant are not performed. A small proportion of infants with BA have an associated syndrome and have one or more congenital malformations and appear jaundiced from birth.
BA is treated by surgically establishing bile flow through a hepatoportoenterostomy, or Kasai portoenterostomy (KPE). This is followed by close monitoring of the child’s nutrition and supportive therapy with prophylactic antibiotics and fat-soluble vitamins supplementation. Follow up aims to assess complications or failure of the KPE.
The need for subsequent liver transplantation increases with the age at the time of surgical intervention, said Dr. Erika Bariciak, an Ottawa neonatologist and Medical Lead of the new BA Screening Program. Best native liver survival rates are achieved when surgical repair is done before 30 days of life, however in Ontario, the median age at time of surgical intervention is currently 66 days with 17 percent having the KPE beyond 90 days of age and only 25 percent receiving surgical intervention before 45 days of age.
When the program launches, parents of all babies born in Ontario will be given an Infant Stool Colour Card (ISCC) — a printed visual reference with photographs that depict a gradient of infant stool colours — and instructed to check their baby’s stool colour daily during diaper changes for the first month of life. (Premature babies are at an increased risk of BA and can sometimes present later so parents of these babies will be instructed to screen their baby’s stool for one month beyond the expected due date, or until one month corrected gestational age). If an abnormally pale coloured stool is noticed, information on the card guides parents to contact NSO; an expedited referral will be made to an academic pediatric hepatologist in Ontario who will help to arrange a confirmatory direct/conjugated bilirubin measurement and follow up with the family remotely. If the bilirubin level is elevated, further arrangements will be made to investigate if BA is the cause of the acholic stools and cholestasis.
The importance of early diagnosis cannot be overstated, said Dr. Carolina Jimenez, an Ottawa pediatric hepatologist who has been a strong advocate for the implementation of BA screening in Ontario. “Unless bile flow is established by surgical intervention through a KPE, children with BA rarely survive beyond two years of age without liver transplantation and mortality is inevitable in cases where no surgical repair or liver transplantation is done,” she said.
In the Canadian experience, babies who have the KPE performed before 30 days of age have a 50 percent 10-year native liver survival rate compared to only 15 percent for those undergoing their surgical intervention before 90 days of age. “The introduction of BA screening is intended to identify cases earlier, improve the success of the KPE, and postpone the need for urgent liver transplant in infancy, when it is technically more challenging and there is a shortage of organs due to size constraints,” said Dr. Jimenez.
The timing of well-baby visits for most newborns in Ontario can be a barrier to early detection of infants with acholic stools, said Dr. Bariciak. An increasing number of parents don’t have timely access to a primary care physician and most well baby visits occur in the first two weeks of life and then at two months of age when the baby receives their first vaccination. “This misses the 2–4-week window when most cases of BA will present and when diagnosis and treatment is most crucial.”
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