Lecture 13 2/11/25 Flashcards
(45 cards)
What are the characteristics of canine chronic hepatitis?
-inflammatory reaction in the liver continuing without improvement for 6+ months
-confirmed via histology
-most common primary liver dz in dogs
-often idiopathic
-higher prevalence of chronic bacterial infections in dogs with CCH
What are possible etiologies for CCH?
-infection
-medications
-toxins
-drug-induced chronic hepatitis
-excess hepatic copper accumulation
-autoimmune chronic hepatitis
What is the most common cause of toxin-induced CCH?
copper accumulation
What is the pathophysiology of CCH?
-hepatic injury results from hepatocellular death and release of inflammatory mediators
-inflammatory cell infiltration and immune system response contributes to ongoing injury
-ongoing injury eventually leads to necrosis and fibrosis
What is the signalment of CCH?
-seen in middle-aged to older dogs
-can be any breed, but some are predisposed
Why do signs of CCH not show up until late in the disease process?
the liver has a large reserve capacity and can continue functioning normally early in disease
Why is it important to test dogs with persistent increases of liver enzymes early?
waiting for clinical signs means the patient will lose a lot of functional liver capacity; early diagnosis can lead to earlier treatment and preservation of function
What are the less specific clinical signs seen in CCH patients?
-fever
-lethargy
-weakness
-hyporexia/anorexia
-weight loss
-abdominal pain
-vomiting/diarrhea
What are the more specific clinical signs seen in CCH patients?
-PU/PD
-icterus
-ascites
-hepatic encephalopathy
What are the characteristics of liver enzyme clin path in CCH?
-liver enzymes are increased in a mixed hepatocellular and cholestatic pattern
-initial increase in leakage enzymes; ALT and AST
-cholestatic enzymes increase later
-enzymes can wax and wane over the course of months
What causes abnormal markers of hepatic synthetic function in CCH?
-hepatocyte loss
-fibrosis limiting normal sinusoidal blood flow
What are the characteristics of ultrasound as a diagnostic tool for CCH?
-not sensitive or specific for the diagnosis of CCH
-may see. small, hyperechoic liver
-helpful to identify neoplastic masses, ascites, and APSS
What are the characteristics of hepatic cytology as a diagnostic tool for CCH?
-inadequate for diagnosis of CCH
-can help to rule out diffuse neoplastic infiltration and suppurative inflammation
What tests need to be done to diagnose CCH?
-histology
-aerobic/anaerobic culture
-copper quantification
What are the histologic features of CCH?
-inflammation in any region of the liver
-hepatocellular death
-variable grades of fibrosis
What are the main management steps for CCH?
-discontinue hepatotoxic drugs
-treat underlying disease; may be enough to stop progression
-antioxidant therapy to control necroinflammatory/cholestatic processes until liver enzymes normalize
What are further recommendations for treatment of CCH?
-antiemetics and gastroprotectants
-antibiotics if bact. infection is suspected
-treatment for fibrosis if present on histology
-protein restriction ONLY if patient develops acquired shunts or hepatic encephalopathy
What are the specific management steps for copper-associated chronic hepatitis?
-lifelong dietary restriction; commercial liver diet + low-copper protein source supplementation
-chelation of copper if concentrations reach 750 ug/g of centrilobular accumulation or 1500 ug/g overall accumulation
What are the characteristics of D-penicillamine?
-bind hepatic copper for elimination in urine
-upregulate metallothionein in enterocytes for fecal elimination of dietary copper
-has anti-inflammatory and anti-fibrotic properties
How long should D-pen be used?
-6 to 9 months until copper concentrations normalize when combined with a copper-restricted diet
-longer if not given with a copper-restricted diet
How is the efficacy of copper hepatitis treatment determined?
-repeat biopsy and quantification is best
-normalization of serum ALT is a good surrogate
Which treatments can be used for maintenance of copper hepatitis?
-D-pen given at a reduced frequency
-administration of zinc to block enteric copper absorption
-D-pen and zinc CANNOT be given concurrently
What are the options for immune modulation in nonsuppurative immune-mediated CCH?
-prednisone/prednisolone
-dexamethasone if ascites occurs
-steroids combined with secondary immunosuppressive med.
-cyclosporine alone
**often lifelong therapy
What is the prognosis of CCH?
-depends on etiology and histologic grade
-infectious and copper-associated hepatopathy have good prognosis
-fibrosis could be reversible; therapy indicated even in severe fibrosis
-ascites and icterus are negative prognostic indicators in dogs with idiopathic CCH