What is Biliary Atresia?

Overview

Do you know what biliary atresia is? It is an extremely complex and rare illness in which the tubes that transport bile from the liver to the intestine become blocked or damaged.^1,2

The liver’s cells create a fluid called bile, which is then transported through the bile ducts to the gallbladder or the intestines. Bile is composed of many constituents, among them being bilirubin and bile salts, to help intestinal absorption or to emulsify dietary fats. When there is an obstruction in the bile ducts, it is called biliary atresia. As a result, bile accumulates in the liver. This can harm the liver, leading to scarring, cirrhosis and liver failure.^1,2

Biliary atresia is one of the leading causes of neonatal jaundice, a condition where the skin and the whites of the eyes have a yellow appearance in infants due to high levels of bile in the body. It accounts for approximately 30% of cases worldwide every year, affecting people assigned female at birth (AFAB) more frequently than people assigned male at birth (AMAB).³

Causes of biliary atresia

This condition can be brought on by several illnesses, as well as genetic predispositions and immunological traumas that can result in bile ducts not developing properly or becoming damaged during pregnancy. 

Biliary atresia can also be a result of environmental causes, such as drug or alcohol addiction during pregnancy, exposure to industrial or agricultural contaminants, and other environmental variables.^1,4

Moreover, the following viral infections have also been linked to biliary atresia:

• Cytomegalovirus
• Reovirus
• Rotavirus⁴

Signs and symptoms of biliary atresia

How could biliary atresia be recognised and what signs should we watch out for? Typically, infants with this illness exhibit the following symptoms during their neonatal period:

• Persisting jaundice, which is presented by the yellowing of the skin and the whites of the eye
• Hepatosplenomegaly
• Dark urine
• Pale stools^1,4 

If this condition is left untreated, it can lead to more serious conditions. These include cirrhosis, liver failure, splenomegaly, accumulation of fluid in the abdomen (ascites), or indications of portal hypertension, which may be deadly.^4,5

Management and treatment for biliary atresia

The management of biliary atresia symptoms will depend on the stage and severity of the illness. However, the main goals are to restore the bile flow and prevent liver damage and other complications. To restore the bile passage, a surgical intervention known as portoenterostomy(or Kasay portoenterostomy), is used. This surgery is used to remove the biliary remnants and reestablish the bile passage in the bile ducts. The procedure involves removing damaged bile ducts and connecting a segment of the small intestine directly to the liver, allowing for bile drainage to occur.^1,4

After the surgery, the condition is managed by takingmedication prescribed by doctors topromote bile drainage, such as glucocorticosteroids which also reduce inflammation. However, corticoids can cause adverse events in patients, inflammation of biliary ducts (cholangitis) being the most frequent. Besides glucocorticosteroids,  ursodeoxycholic acid can also be prescribed to relieve pruritus, an itchthat results from the ineffective transport of bile through the biliary system (cholestasis).^1,4,6

Although surgery, followed by medication, is a successful approach to treating biliary atresia, a liver transplant may be required in the long term.⁷

Diagnosis of biliary atresia

Since biliary atresia may present similarly to other causes of newborn jaundice, a correct diagnosis can be extremely hard to make. Paediatric hepatologists, or physicians who treat children with liver diseases, may request a physical examination, medical history, blood tests, imaging studies, and a liver biopsy to confirm the diagnosis.⁸

Blood testing - Doctors may request tests for factors related to the liver, such as gamma-glutamyl transferase, transaminases, and direct and indirect bilirubin.

Imaging studies - Although ultrasonography is a very simple and non-invasive diagnostic test, it offers crucial insight into the condition of the liver's vascularisation and detects the presence of ascites. This makes it possible to rule out otherr causes of jaundice. However, certain techniques are less commonly used since they can be difficult to employ on new-borns and are more invasive, such as:

• Hepatobiliary scintigraphy involves injecting a radioactive substance into the bloodstream; if the radioactive substance is not eliminated by the liver, the patient may have biliary atresia
• Duodenal intubation involves injecting dye into the gallbladder; if the dye is detected in the duodenum, there is no blockage in the bile ducts, eliminating the possibility of biliary atresia
• Magnetic resonance cholangiopancreatography and magnetic resonance imaging (MRI)

Liver biopsy - although invasive, this procedure can provide crucial information that can eliminate other causes of jaundice to be differentiated from biliary atresia. It involves taking a piece of tissue from the liver toexamine liver cells under a microscope.¹

Risk factors

Even though the risk factors are not yet fully understood, some possible factors may increase the chances of developing biliary atresia. The possible risk factors are:

• Infections with certain viruses
• Coming into contact with harmful chemicals
• Immune system problems
• Adverse events during pregnancy stages when the liver and bile ducts are developing in the foetus  Genetic predisposition
• Gestational diabetes^1,9

Complications

Biliary atresia can cause a variety of further issues, such as malnutrition, impaired growth, infections, bleeding, fluid retention, and finally, liver failure.

Infants with biliary atresia may continue to have a decreased flow of bile to the intestines even after receiving treatment, which impairs the absorption of nutrients and the breakdown of lipids. Due to this, the babies' levels of proteins and vitamins will be poor. Furthermore, one of the probable outcomes of biliary atresia is cirrhosis, whichis damage to the liver that can lead to other difficulties. This includes portal hypertension, a condition that manifests ashigh blood pressure in a blood vessel that transports blood from the intestines to the liver (portal vein). In this circumstance, infants might suffer from ascites. Infants require a liver transplant if the consequences are severe enough to cause liver failure.^4,5

FAQs

How can I prevent biliary atresia?

There is no possible way tocompletely prevent biliary atresia, although there are ways to reduce the severity of the condition if you know the signs and symptoms as this will allow for the earliest possible diagnosis and treatment.

How common is biliary atresia?

Approximately 30% of annual neonatal jaundice cases worldwideare attributed to biliary atresia, affecting people AFABmore commonly than people AMAB.³

When should I see a doctor?

You should see a doctor if your baby presents jaundice that does not improve after two weeks of age.¹

Summary

Biliary atresia is an uncommon illness that affects newborns. A blockage or injury to the bile ducts, structures that transport bile from the liver to the small intestine, causes it to occur. A substance called bile helps the body eliminate waste and digest fats. Bile obstruction in the liver results in cirrhosis and liver damage.

The primary sign of biliary atresia is jaundice. However, this can be accompanied by fluid in the belly, light-coloured faeces, dark urine, poor weight gain, and an enlarged liver or spleen. Surgery is the primary treatment for biliary atresia and establishes a new bile drainage conduit from the liver. However, many kids with biliary atresia will eventually require a liver transplant.