What can be a symptom of biliary atresia?

The presence of dark urine can be a symptom of biliary atresia because this condition obstructs the normal flow of bile from the liver to the intestines. When bile is unable to reach the intestines, it leads to an accumulation of bilirubin in the bloodstream, a substance that is produced when the liver breaks down red blood cells. Elevated levels of bilirubin cause jaundice, which often manifests as yellowing of the skin and eyes, but can also cause the urine to take on a darker color due to increased bilirubin excretion by the kidneys.

In contrast, bright red stools suggest the presence of fresh blood, which is not typically associated with biliary atresia but rather with gastrointestinal bleeding. Occasional diarrhea may be a nonspecific symptom and is not directly linked to biliary atresia, as this condition primarily affects bile flow rather than causing diarrhea. Lastly, while it's possible for a very early stage of the disease to present with few overt symptoms, biliary atresia usually leads to noticeable signs like jaundice and dark urine relatively quickly after birth. Thus, dark urine is a key indicator of the underlying pathology associated with biliary atresia.