Definition

Biliary atresia refers to the obstruction of the hepatic ducts responsible for transporting bile from the liver to the gallbladder. This disorder is present from birth or acquired congenitally. The two types of bile ducts are external (extrahepatic) ducts and internal (intrahepatic) ducts. Biliary atresia is a condition in which the bile ducts, either inside or outside the liver, cannot develop perfectly, resulting in obstruction or blockage.

Biliary atresia is an uncommon condition. Nevertheless, without receiving appropriate medical intervention, biliary atresia might result in mortality in pediatric patients. In fact, the survival rate for untreated children with biliary atresia is less than 10% by the age of 3 years old.

Causes

The specific etiology of biliary atresia remains unknown. Nevertheless, it is acknowledged that a proportion ranging from 3 to 20 percent of children diagnosed with biliary atresia also present with additional congenital anomalies, suggesting the potential for hereditary transmission of this medical condition.

These factors lead to improper development of the bile ducts in infants with biliary atresia, resulting in a blockage or obstruction of the bile ducts responsible for transporting bile from the liver to the gallbladder. Furthermore, inadequate treatment of this condition may result in liver injury and cirrhosis of the liver. Biliary atresia has the potential to result in mortality.

Risk factor

A familial history of biliary atresia or genetic factors increases the risk of biliary atresia in children.

Symptoms

In newborns with biliary atresia, symptoms may not be immediately apparent at birth. However, within the first month of life, jaundice can emerge, marked by a yellowish discoloration of the skin. As time progresses, the jaundice may become more severe, accompanied by signs such as irritability and noticeable weight loss.

Additional symptoms that may manifest in children with biliary atresia include dark-colored urine, splenomegaly, malodorous feces or stools, pale-colored stools resembling epoxy, and weight gain difficulties or non-gain of weight. Additionally, children may encounter a deceleration in their development rate.

Diagnosis

To diagnose biliary atresia, the doctor typically conducts a thorough interview with the parents, inquiring about symptoms commonly linked to the condition. A physical examination is then performed to evaluate hepatomegaly, which is an enlargement of the liver. Additionally, specific laboratory tests may be recommended to measure the levels of direct bilirubin and total bilirubin, aiding in the diagnosis process.

Radiographic examinations of the abdomen, including X-rays or ultrasonography (USG), are routinely conducted. Radiological imaging is recommended to identify abnormalities in the biliary ducts. Contrasts are required to perform X-ray imaging of the biliary ducts. The medical procedure in question is referred to as a cholangiogram.

The Hepatobiliary Iminodiacetic Acid (HIDA) scan is a diagnostic procedure used to evaluate the functionality of the bile ducts and bladder.

In severe cases and also cirrhosis, a liver biopsy might be performed. A biopsy involves collecting small tissue samples from the patient for microscopic examination.

Management

Biliary atresia is a congenital anomaly marked by the abnormal development of the bile ducts. These ducts play a crucial role in transporting bile from the liver to the gallbladder and then to the intestines. To address this condition, a surgical intervention called the Kasai operative procedure may be recommended. During this procedure, surgeons create a new pathway between the liver and the small intestine, facilitating the proper flow of bile. This intervention aims to alleviate the obstruction and improve liver function in affected individuals.

The Kasai surgical technique has a success rate of 60 percent, which may increase the life expectancy of children with biliary atresia. Performing the Kasai surgery at an earlier stage decreases the risk of children with biliary atresia requiring a liver transplant.  For optimal outcomes, it is recommended that this treatment be carried out on infants diagnosed with biliary atresia aged 10 weeks.

It is optimal to perform this surgery prior to the infant reaching 8 weeks of age. Nevertheless, in certain cases, such as when infants have biliary atresia together with liver cirrhosis or failure following the Kasai surgical operation, a liver transplant or replacement may still be necessary as a form of treatment.

Complications

Left untreated, biliary atresia can lead to mortality, particularly in pediatric patients. Even with surgical intervention, complications can still arise. These may include cholangitis, an inflammation of the bile ducts; portal hypertension, which is increased blood pressure in the portal vein system; the development of esophageal varices, which are enlarged veins in the esophagus; and the risk of cancer. Regular monitoring and management are crucial to address and mitigate these potential complications in affected individuals.

The specific etiology of post-operative cholangitis remains unknown. Post-operative cholangitis in children causes fever, jaundice, and liver enzyme elevation. This requires immediate treatment.

The majority of children with biliary atresia, along with liver fibrosis, will encounter elevated portal venous pressure. Elevated portal vein pressure is indicative of a negative prognosis due to its potential to advance into portal hypertension, variceal hemorrhage, and terminal liver failure.

Elevated portal blood pressure may induce the development of varicose veins or dilation of the blood vessels in the esophagus. Medically, this condition is referred to as esophageal varices. Approximately 60% of patients who received the Kasai surgical procedure for biliary atresia develop esophageal varices around 2 to 3 years after the surgery. Approximately 30 percent of individuals will experience bleeding varices. Esophageal varices are viscous and prone to hemorrhaging. Esophageal varices can cause massive, potentially fatal bleeding. Endoscope surveillance is recommended for all children with biliary atresia to help avoid further bleeding.

Malignancy is a potential complication in children with biliary atresia. Nevertheless, instances of this malignancy are infrequent, and the precise etiology remains unidentified. Malignancies frequently occur in pediatric patients with biliary atresia who develop liver fibrosis following the Kasai surgical intervention.

When to see a doctor?

Consult your pediatrician immediately if your child exhibits multiple symptoms, including jaundice or yellowing of the skin during the second and third weeks of life, dark urine, splenomegaly, pale stools resembling epoxy, and retarded growth. Early detection of biliary atresia in children is crucial, as early treatment increases beneficial outcomes. If the Kasai procedure is effective and results in positive results, children with biliary atresia are less likely to require a liver transplant and have a higher probability of survival.