Important Features of Acquired and Congenital Hepatobiliary Disorders

––––--ACQUIRED---------			––––-CONGENITAL---------
Early signs	Major bile duct occlusion	Severe hepatic insufficiency	PSVA, PSS	Microvascular dysplasia^a (no PSVA, microscopic shunting)	Ductal plate malformation
Vomiting	± Vomiting	± Vomiting	Abnormal behavior: lethargic	Liver ± small, low normal	Liver ± small, low normal size
Diarrhea/constipation	± Diarrhea/constipation	± Diarrhea/constipation	± Diarrhea/constipation	No clinicopathologic markers except ↑↑↑ bile acids	± Liver lobe hypoplasia
Weight loss	Weight loss	Weight loss	Weight loss		± Gallbladder atresia/hypoplasia
Pyrexia	Pyrexia	± Pyrexia	± Pyrexia	Protein C: normal (usually)	Predisposed to cholangitis
“Noisy enzymes”	Polydipsia	Polyuria/polydipsia	Polyuria/polydipsia	No hepatic encephalopathy	± Pyrexia if cholangitis
Normal bilirubinemia	Jaundice within 72 hours	Jaundice as disease advances	No jaundice	Variable liver enzymes: most common ↑ ALT, ↑ALP with inflammatory bowel disease	Variable enzymes: ↑ ALT, ↑ ALP ↑ with inflammatory bowel disease
Clear to yellow urine	↑ ALP & GGT	Variable ↑ ALP, AST, ALP, GGT	↓ RBC, MCV, ↓ BUN, ↓ creatinine
Normal bile acids	↑ ALT & AST, ↑ cholesterol	Gradual decline in cholesterol ↓ cholesterol	Variable liver enzymes ↓ cholesterol		No jaundice unless severe cholangitis
Polyuria/polydipsia	Orange urine ± neg urobilinogen: unreliable	Clear to orange urine urobilinogen "+" ↑↑↑ bile acids bruising/bleeding tendencies	Ammonium biurate crystalluria Normal coagulation ↑↑↑ bile acids		No ammonium biurate crystalluria unless acquired portosystemic shunts form secondary to congenital hepatic fibrosis Rarely dogs have PSVA—no ascites
	Bleeding tendencies: 7–10 days	Brown to melenic feces	↓ Protein C (< 70%) often
	Acholic (pale) feces	Brown feces	Copper-colored iris: cats
	Melenic feces if GI bleeding	Green feces: ↑ stercobilin	Typically no ascites
	Gastrointestinal ulceration	Normal to microhepatica: dog	Young dogs: melena—parasites
	Hepatomegaly: firm; rounded borders	Hepatomegaly: cat	Microhepatica with “plump” kidneys
	Palpable gallbladder: cat if chronic: > 6 weeks ascites edema (rare in cats)	Gastroduodenal ulceration associated with portal hypertension ascites if: portal hypertension ascites if: portal hypertension: ↓ albumin fosters ascites acquired portosystemic shunts	± Cryptorchid (small-breed dogs) ptyalism (cats) rare gastrointestinal ulceration: ↑ risk for hepatic encephalopathy portal hypertension: only if intolerant to shunt ligation, true portal atresia, or arteriovenous malformation ascites rare unless portal vein atresia or hepatic arteriovenous fistula edema does not occur
		HE: variable stupor, lethargy, depression pacing, head pressing rarely coma, seizures hyperammonemia: usually coincides with HE signs ammonium biurate crystalluria cystic/renal calculi urinary tract obstruction pollakiuria: urinary calculi	HE: common tooth eruption bleeding →↑ risk HE GI bleeding: parasites →↑ risk HE amaurosis, stupor, depression, head pressing pacing, aggression (esp cats), ptyalism seizures with prolonged prodrome hyperammonemia: usually coincides with HE ammonium biurate crystalluria: common with HE
			Ammonium urate cystic calculi: less common renal calculi may present for urinary obstruction →↑ BUN → NH₃ →↑ risk HE hematuria: due to urinary bladder calculi
^aDoes not limit lifespan PSVA, portosystemic vascular anomaly. PSS, portosystemic shunt. ALP, alkaline phosphatase. GGT, gamma glutamyl transferase. MCV, mean corpuscular volume. HE, hepatic encephalopathy.

In these topics

Clinical Features of Hepatobiliary Disease in Small Animals