Chronic active hepatitis in dogs: symptoms, diagnosis and treatment – Chronic active hepatitis is a chronic and progressive inflammation of the liver which results in the replacement of normal liver tissue with scar tissue. In most cases, the cause of chronic active hepatitis is never discovered. Potential causes include: canine hepatitis virus (adenovirus I), leptospirosis, copper storage disease, drug toxicity and genetic factors. The immune system’s reactions to liver inflammation can contribute to the progressive aggravation of the disease.
All dog breeds can be affected by chronic active hepatitis, although the incidence is higher in the following breeds: Bedlington Terrier, West Highland White Terrier (or Westie), Dobermann Pinscher, Cocker Spaniel and Skye Terrier. Chronic active hepatitis usually occurs in middle-aged animals and it seems that females are more at risk.
- Ascites (collecting fluid in the abdominal cavity)
- Jaundice (yellowing of the skin)
- Increased bleeding tendency
The duration of the disease can vary from weeks to months. In the terminal stages, when the scarring of the liver is so severe as to compromise normal liver function, affected dogs can develop an accumulation of fluid in the abdomen and signs of hepatic encephalopathy.
There are several pathologies that may seem similar to chronic active hepatitis, including:
- Liver cancer, such as lymphosarcoma
- Hepatotoxicity, i.e. chemicals or drugs that damage the liver
- Chronic hepatitis due to bacterial, fungal, protozoan or parasitic infections
- Chronic liver disease due to an abnormal deposit and accumulation of copper in the liver
- Pancreatitis, an inflammation of the pancreas that often causes vomiting, lethargy and loss of appetite
- Pancreatic neoplasm that causes biliary tract obstruction
- Intestinal inflammation, intestinal neoplasms or the presence of foreign bodies in the intestine
- Primary pathologies of the gallbladder such as stones, neoplasm, inflammation or infection
- Other causes of clotting abnormalities (blood clotting disorders)
The clinical signs associated with chronic active hepatitis are rather vague and nonspecific. Therefore the veterinarian may not be able to make a presumptive diagnosis without first carrying out certain diagnostic tests.
The first tests that the vet will perform will be medical history and thorough physical examination. The tests that we will list below are generally conducted subsequently in order to exclude the presence of other pathologies and confirm a diagnosis of chronic active hepatitis:
- Complete blood count test. It can reveal values within normal limits. It can also reveal mild anemia, an increase in white blood cells and a low level of circulating proteins.
- Biochemical profile. Usually it reveals an increase in liver enzymes. Other abnormalities may be observed, such as elevated bilirubin levels (evidence of jaundice), low circulating protein levels, low blood sugar levels, low blood urea nitrogen levels and low cholesterol levels. Electrolyte disturbances are also common, such as low potassium levels, low chloride levels and high sodium levels.
- Urine analysis. It is useful for evaluating the animal’s kidney function and hydration level. Sometimes it can detect the presence of bilirubin in the urine.
- Serum bile acid examination. Generally, high levels are found which denote the inability of the liver to function properly. Bile acid measurement is performed in patients who have normal bilirubin levels.
- Coagulation profile. It is carried out because coagulation disorders are common in the presence of chronic liver disease. Also, taking a liver biopsy is much more dangerous if the blood can’t clot properly.
- Blood tests. They can be useful for detecting alterations in ammonia levels in the blood, especially if the animal manifests killing, disorientation, convulsions or other signs of hepatic encephalopathy.
- Abdominal radiographs. The results can reveal normal values, although they can reveal the presence of fluid in the abdomen (ascites), enlarged liver (hepatomegaly) or small liver (microhepathy).
- Abdominal ultrasound. It is recommended in most cases. It is extremely useful for evaluating the abdominal organs, including the liver. It is also important to rule out the presence of other pathologies that may initially be difficult to differentiate from chronic active hepatitis. Using this procedure it is often possible to obtain a liver sample for subsequent evaluation, culture / sensitivity test. Before being able to carry out this procedure it is however advisable to carry out a coagulation profile and the sample should be taken only if the coagulation parameters are within normal values.
The veterinarian may recommend further tests to rule out or diagnose concomitant conditions and to confirm the diagnosis of chronic active hepatitis. These exams are chosen on an individual basis:
- Laparoscopy. It is a procedure that allows the visualization and sampling of the abdominal structures by means of a small tool that is introduced into the abdomen through a small incision. It is a more invasive procedure than the ultrasound-guided biopsy, but allows the veterinarian to directly observe the liver and the structures associated with it. It helps to ensure that the biopsy sample is taken from a liver area that has obvious anomalies. This procedure requires the use of a general anesthesia.
- Laparotomy. It is an exploratory abdominal surgery. Allows close inspection of the entire liver organ and other abdominal structures. It allows the collection of large biopsy specimens and can be indicated in cases where it is necessary to relieve and deflect an obstruction of the biliary tract. It also provides a mechanism for removing certain masses and tumors that may be responsible for clinical signs.
- Hospitalization and support therapy (fluid therapy and electrolytic therapy) in the presence of dehydration due to vomiting, diarrhea and severe anorexia
- Treatment of any underlying ailments
- Nutritional support and nutrition management
- Corticosteroid administration to reduce inflammation
- Administration of drugs designed to stimulate the liver (choleretic) to increase biliary secretion
- SAMe to improve liver metabolism
- Drugs capable of chelating copper or reducing its absorption by the liver
- Diuretics to promote the reduction of water retention in the body
- Vitamin K supplementation
- Antifibrotic agents to reduce liver scarring
There are no preventive measures for this pathology, although performing biochemical profiles in dogs of susceptible breed and starting therapy in the asymptomatic phases will help to slow down the progression and development of serious clinical signs.