Jaundice in dogs: prehepatic, hepatic or posthepatic

Question

9-year-old Miniature Schnauzer with a history of pancreatitis. He has had vomiting, marked jaundice and pale faeces for a week.

Parameter	Result	Reference
Haematocrit	44 %	37–55
Total bilirubin	8.2 mg/dL	0.0–0.4
Alkaline phosphatase (ALP)	2,150 U/L	20–150
GGT	68 U/L	0–10
ALT	420 U/L	10–100
Cholesterol	480 mg/dL	130–300

How do you classify the jaundice and what is the most useful next step?

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A. Prehepatic; Coombs' test and blood smear for spherocytes

Prehepatic (haemolytic) jaundice is accompanied by anaemia, usually regenerative. With a normal haematocrit, haemolysis cannot explain a bilirubin of 8 mg/dL.

B. Hepatic; measure pre- and postprandial bile acids

Bile acids add no information in an icteric patient without haemolysis: they will be high because of the cholestasis itself, whether hepatic or posthepatic.

C. Hepatic; immediate liver biopsy

Before a biopsy, an obstructive cause must be ruled out by imaging and coagulation assessed. Extrahepatic obstruction requires surgery, not biopsy.

D. Probably posthepatic; abdominal ultrasound to look for biliary obstruction

Correct. With no anaemia, very high ALP and GGT, hypercholesterolaemia, acholic faeces and a history of pancreatitis, extrahepatic biliary obstruction is most likely. Ultrasound shows common bile duct dilation and the cause (pancreatitis, mucocele, choleliths, neoplasia).

lightbulb Key takeaway

With jaundice, look at the haematocrit first: if there is anaemia, think haemolysis; if not, distinguish hepatic from posthepatic causes with ultrasound. Do not request bile acids in an icteric patient without haemolysis.

How do you classify the jaundice and what is the most useful next step?

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