Question

In neonatal cholestasis, if the serum gamma-glutamyl transpeptidase (GGT) is more than 600 IU/L, the most likely diagnosis is:

• A. Neonatal hepatitis
• B. Choledochal cyst
• C. Hypothyroidism
• D. Biliary atresia

Hint:

GGT over 600 in neonatal cholestasis points to bile duct obstruction, most often biliary atresia.

Answer 1

The Correct Option is D

GGT is an enzyme found on bile duct cells. Its level in the blood helps tell apart liver cell disease from bile duct disease in a baby with cholestasis (yellow skin from poor bile flow).

1. Neonatal hepatitis: mainly damages liver cells, so it usually pushes up AST and ALT sharply while GGT stays only mildly to moderately high, well under the level in this question.
2. Choledochal cyst: can raise GGT since it is also an obstructive problem, but it is a rare cause of neonatal cholestasis and usually comes with a cyst visible on ultrasound, so it is not the most likely answer here.
3. Hypothyroidism: can slow bile flow and cause cholestasis, but the GGT rise is usually mild, and the baby shows other clues like lethargy and poor feeding along with an abnormal thyroid test.
4. Biliary atresia: the extrahepatic bile ducts are destroyed and blocked from early life, which puts constant strain on duct cells and drives GGT to very high levels, often past 600 IU/L. It is also the single most common obstructive cause of neonatal cholestasis.

Since a GGT this high points to bile duct obstruction rather than plain liver cell injury, and biliary atresia is both obstructive and common, it fits best.

Let's summarize:

• High GGT means bile duct strain or obstruction, not just liver cell injury.
• Biliary atresia is the most common and most likely obstructive cause behind a GGT above 600 IU/L.

So the most likely diagnosis is biliary atresia.