Liver disease — clinical and histological standardization

WSAVA guideline

Key findings

• Database: book starts once disease apparent (↑enzymes, bile acids, icterus); blood tests not decisive, weak except vascular disorders (Ch1 p2).
• Ammonia/ATT: fasting ammonia >100 µmol/L (ref ≈45–100) = shunting; ATT 2 ml/kg 5% NH4Cl deep rectally (10–15 cm), 0/20/40 min, ≥doubling positive; bile acids less specific; on ice ≤40 min, no haemolysis (RBC 3× plasma) (Ch4 pp29–30).
• Imaging: 7 standard planes; CPSS only if traced origin→termination; dilated left gonadal vein (dog) = acquired collaterals (Ch3).
• Biopsy: 1 core ≈1/50,000th of organ → 2–3 samples; contraindicated: severe coagulopathy, fibrinogen <1 g/L (<50% lower 95% ref; Utrecht 1000 dogs: 6% excluded, 3 bleeds); coags ≤24 h; 12 h fast; general anaesthesia cats; no biopsy guns in cats (Ch2 pp2–10).
• Histopathology: H&E; fibrosis = reticulin (Gordon & Sweet)/Sirius red/trichrome/Van Gieson; copper = rubeanic acid/rhodanine; + PAS, Ziehl-Neelsen/diastase-PAS, Perl's, Congo red/Stokes, Fouchet's; cores ≥1 cm, 10–11 portal tracts, ≥3 fields/10×; section thickness [verify] (Ch2; Ch7 p38).
• Nomenclature: PHPV replaces microvascular dysplasia; interface hepatitis replaces piecemeal necrosis (Ch4; Ch7).
• Cholangitis: neutrophilic (ascending E. coli etc.; 🐈); lymphocytic (chronic, essentially 🐈); destructive (🐕, TMPS); fluke; cat = biopsy + bile cytology AND culture (Ch5).
• Cirrhosis: diffuse fibrosis + abnormal nodules + portal-central anastomoses (micro <3 mm, macro >3 mm); porto-portal alone = biliary-type, NOT cirrhosis; hepatocutaneous syndrome = superficial necrolytic dermatitis (↑Shih Tzu) (Ch7).
• Grading/copper: activity 0–5, fibrosis 0–4, copper 0–5+ (0–2+ normal; 3+–5+ pathological), steroid 0–3; ≤400 µg/g dry weight normal, >2,000 damage, Skye 800–2,200; metal-free saline-free container (Ch7; Ch2).

Drugs named in WSAVA’s own guideline text

As printed in WSAVA’s document, not this app’s own extracted data — see “Related drugs in this reference” below for that.

• Ammonium chloride (NH4Cl) 5% (🐕)

  Ammonia tolerance test (Ch4)

• Vitamin K1 (🐈)

  Pre-biopsy coagulopathy (Ch2)

• Prednisolone (🐕)

  Raises fibrinogen >1 g/L, >90% (Ch2)

• Fresh frozen plasma (🐕🐈)

  Borderline coagulation (Ch2)

• Lidocaine (🐕)

  Biopsy anaesthesia (Ch2)

• D-penicillamine (🐕)

  Steroid-hepatopathy-like change (Ch6)

• Trimethoprim-sulfonamide (🐕)

  Destructive cholangitis (Ch5)

• Carprofen (🐕)

  Idiosyncratic necrosis (Ch7)

• Amiodarone (🐕)

  Idiosyncratic necrosis (Ch7)

• Diazepam (🐈)

  Idiosyncratic necrosis, cats (Ch7)

• Acetaminophen (paracetamol) (🐕🐈)

  Dose-dependent toxicity (Ch7)

• Phenobarbital (+primidone, phenytoin) (🐕)

  Anticonvulsant hepatitis (Ch7)

Recommendations

• Histology central except vascular disorders (Ch1 p2)

  Expert consensus (WSAVA Liver Standardization Group)

• Disease evident → imaging + tissue, not blood tests (Ch1 p2)

  Expert consensus (WSAVA Liver Standardization Group)

• Fasting ammonia first (>100 µmol/L); ATT 2 ml/kg 5% rectally (Ch4)

  Expert consensus (WSAVA Liver Standardization Group)

• Biopsy: 12 h fast, coags ≤24 h, fibrinogen <1 g/L contraindicates (Ch2)

  Expert consensus + empirical Utrecht criterion (1000 dogs)

• Standard stains; unified nomenclature (PHPV, cirrhosis definition) (Ch2; Ch4; Ch7)

  Expert consensus (WSAVA Liver Standardization Group)

• Grade 0–5, stage 0–4, copper 0–5+; >2,000 µg/g = damage (Ch7)

  Expert consensus (WSAVA Liver Standardization Group)

Related drugs in this reference (4)

The quoted line under each drug is its own already-extracted indication text that matched this condition — the reason it’s listed, not a paraphrase. Open a drug for its full species/route breakdown, calculator, and complete adverse-effect list.

Showing 4 of 4 linked drug records. Open a record for species, route and source details.

• MIRTAZAPINE

  “Anorexia associated with CKD/azotemia, CHF, GI disease, hepatic disease, neoplasia; nausea/vomiting incl. chemotherapy-induced; peri-operative inappetence”

  Source dose preview: 0.6 mg/kg; weight bands: <20 lb = 3.75 mg; 21–50 lb = 7.5 mg; 50–75 lb = 15 mg; >75 lb = 30 mg, q24h (or 15 mg q12h for >75 lb), PO (Dog)

  Adverse-effect notes: Sedation/drowsiness — Main, dose-dependent · Vocalization, increased affection — Notable

• SAM E

  “Adjunct for liver disease: chronic hepatitis, feline hepatic lipidosis, cholangiohepatitis/triad disease, vacuolar hepatopathy”

  Source dose preview: 20 mg/kg (≈18 mg/kg per Denosyl dosing), q24h **on empty stomach (≥1 h before food)**, PO (Dog)

  Adverse-effect notes: Well tolerated — Main experience · Occasional GI upset / vomiting — Possible, reduced by empty-stomach dosing with water

• SILYMARIN

  “Adjunctive therapy of chronic liver disease; hepatic recovery/regeneration support; fibrosis; ameliorating anticonvulsant hepatotoxicity”

  Source dose preview: 20–50 mg/kg/day (or 50–200 mg fixed), q12–24h, PO (Dog)

  Adverse-effect notes: Generally well tolerated — — · Occasional GI upset (nausea→diarrhea) — Human-reported

• URSODIOL

  “Adjunctive therapy of chronic hepatobiliary disease — cholestasis, cholangitis/cholangiohepatitis, chronic (active) hepatitis, copper-associated hepatopathy, fi…”

  Source dose preview: 10–15 mg/kg (range 5–15), q24h or divided q12h, PO (Dog)

  Adverse-effect notes: Taurine depletion — Theoretical concern with chronic feline use · Generally well tolerated — Limited use but no hepatotoxicity signal