Chronic canine hepatitis: diagnosis, treatment and prognosis
What is chronic canine hepatitis?
Nomenclature and definition criteria have recently been consolidated and chronic canine hepatitis is now defined as moderate to severe inflammation in the portal areas, with necrosis of the hepatocytes adjacent to the portal space, which is occasionally joined between lobes, in dogs with clinical signs and laboratory abnormalities indicative of liver disease.
Among the most closely studied causes are those related to copper accumulation in the hepatocytes. In many cases, chronic hepatitis develops into cirrhosis. There is a clear predisposition to certain breeds; Bedlington Terrier, West Highland White Terrier, Dobermann, English and American Cocker Spaniels, Poodle and Labrador Retriever.
Among those of infectious aetiology, it is worth mentioning chronic canine hepatitis associated with leishmaniasis (Leishmania infantum).
Diagnostic tests
- Histology: it is essential to correctly diagnose chronic canine hepatitis by means of a liver biopsy. The severity is reflected by the level of necroinflammation (minimal, mild, moderate or severe), while the chronicity reflects the extent of fibrosis (none, mild, moderate, severe or cirrhosis).
- Ultrasound: masses, microhepatia, venous abnormalities and biliary abnormalities may be observed, many of them associated with specific histopathological alterations. However, ultrasound liver abnormalities have significant limitations in terms of determining the underlying liver disease.
- Laboratory tests: these will show altered blood counts (anaemia, leukocytosis, thrombocytopaenia), coagulopathy (PT and aPTT prolongation, decreased platelets, AT and factor IX, especially in the case of cirrhosis), blood chemistry abnormalities (elevated transaminases and alkaline phosphatase, hypoalbuminaemia, hypocholesterolaemia, hyperglobulinaemia).
Clinical signs
Most patients have nonspecific clinical signs that are usually detected when the disease is already in an advanced stage or by chance in a routine analysis.
Dogs with chronic copper-associated hepatitis develop clinical signs late in the course of the disease, although copper may begin to accumulate when the dog is 5–6 months old (Labrador Retriever).
The following should be noted in relation to the clinical picture:
- When there are no signs of liver failure, dogs usually show lethargy, lack of appetite, weight loss, and/or vomiting.
- When there is evidence of liver failure (cirrhosis), the above signs are frequently accompanied bydiarrhoea, weakness, polyuria/polydipsia, possibly jaundice and/or ascites (uncommon), and on rare occasions there could be seizures (due to hepatic encephalopathy), bleeding and fever.
- Some characteristics are breed specific:
- BEDLINGTON TERRIER. There are three different types of presentation: an acute pattern with a low survival rate characterised by copper-associated haemolytic anaemia, haemoglobinuria and jaundice due to acute liver necrosis in dogs under 6 years with a low survival rate; the condition is slow and progressive in adult and elderly dogs; and there is an asymptomatic group whose condition can develop into either of the patterns.
- WEST HIGHLAND WHITE TERRIER. Asymptomatic patients with nonspecific clinical pictures.
- DOBERMANN. Marked predisposition in females of all ages. Clinical picture associated with chronic liver disease.
- COCKERS. Predisposition in young adult males, courses with a severe clinical pattern.
Idiopathic chronic hepatitis affects adult dogs, with no predisposition for sex or breed, coursing with a clinical picture of chronic liver disease.
Treatment of chronic canine hepatitis
Treatment is based on the use of copper chelators (penicillamine and trientine), in the case of CH in Bedlington Terriers. In other breeds, supportive treatment and a low-copper diet may be effective.
Prognosis
The literature indicates that the lack of an early diagnosis, signs of progression to liver cirrhosis and elevated total serum bilirubin are associated with a poor prognosis in chronic idiopathic canine hepatitis.
