An O+ four-week-old infant boy is brought into the office with his mother because over the last two weeks she has noticed her son is looking “yellow”. He was born at 39 weeks’ gestation by normal spontaneous vaginal delivery with no complications to a 30-year-old mother, with regular prenatal care, whose blood type is O+. The mother states he has been breastfeeding every 2-3 hours for 15 minutes on each breast. The boy currently has 5 wet diapers and 5-6 bowel movements with pale colored stools. Vitals are normal. Physical exam is notable for jaundice from head to toe, normal heart and lung sounds, and liver edge palpable 4 cm below the right costal margin. CBC and liver panel results are below:
What is the next best step in managing this patient?
A) Coomb’s Test
B) Abdominal Ultrasound
C) Alpha-1 antitrypsin level
D) Intraoperative cholangiography
E) Magnetic Resonance Cholangiopancreatography (MRCP)
B) Abdominal Ultrasound
This infant is most likely suffering from biliary atresia (BA), a rare disease of the extrahepatic bile ducts of the biliary system. This patient has a hyperbilirubinemia resulting from obstructive jaundice from the post hepatic blockade of the biliary system. Lab values that support this are the elevated alkaline phosphatase, GGT, total bilirubin with majority of it being direct bilirubin. Signs and symptoms of disease tend to appear >2weeks and include jaundice, acholic (clay-colored) stools, darkening of the urine, and hepatomegaly. These patients are also very susceptible to fat soluble vitamin deficiency due to bile not reaching the intestines to allow for digestion and absorption. Treatment is a portoenterostomy (Kasai procedure) with the caveat that early surgical intervention leads to better outcomes and less need for liver transplant in the future. Currently, 60-80% of patients with BA will eventually require liver transplantation. Indications for liver transplantation include complications of portal hypertension, growth failure, and progressive liver dysfunction.
When BA is suspected, ultrasound is the next best step because it is an easily available, inexpensive, and non-invasive test that can assess anatomy as well as exclude other causes of obstructive jaundice. Coomb’s testing is used when assessing autoimmune causes of indirect hyperbilirubinemia. Although some forms of alpha 1 antitrypsin deficiency can cause this presentation and it is reasonable to order a level, the results will take time and BA must be differentiated from other causes of cholestasis promptly because early surgical intervention results in better patient outcomes. Intraoperative cholangiography can confirm a diagnosis of biliary atresia, however is invasive. MRCP findings in infants with BA include incomplete visualization of the extrahepatic biliary system, however this requires sedation of the infant and should not be used before an abdominal ultrasound.
