Cirrhosis is advanced fibrosis of the liver characterized by loss of normal hepatic architecture. Usually, it occurs as a result of chronic attacks on the liver that are added to the failure of the regeneration mechanism of this organ. Despite the fact that it is a degenerative, chronic and irreversible process, it is important to establish adequate treatment in order to prevent the progression of fibrosis and to treat the complications associated with this process.
If you want to know more about cirrhosis in dogs, causes, symptoms and treatment, we recommend that you join us in the following article of our site in which we explain the most important aspects of this liver problem, including the diagnosis as well.
What is cirrhosis in dogs?
Cirrhosis is an advanced fibrosis of the liver where the normal hepatic architecture is lost. It is a degenerative, chronic and irreversible process of the liver that is produced by the sum of two factors:
- Chronic attacks on the liver: Generally caused by liver disease or poisoning that affects the liver.
- Failure in the regeneration mechanism: The liver is an organ with a great power of regeneration, so much so that it is capable of regenerate completely from only 30% of its size. However, when this regeneration mechanism fails, cirrhosis appears.
The liver's attempts to regenerate its hepatocytes give rise to an abnormal proliferation of these cells, which are associated forming nodules without structure or function, which are known as regeneration nodes.
On the other hand, the damaged parenchyma of the liver is replaced by connective tissue, thus appearing a severe fibrosis that further compromises the structure and liver function. Sometimes abnormal proliferation of the biliary system is stimulated at the same time, leading to biliary hyperplasia.
Therefore, at the microscopic level the following characteristics can be observed:
- Regeneration nodules: with loss of the lobular structure typical of the liver
- Severe fibrosis.
- Biliary hyperplasia (not always).
At the macroscopic level, the characteristics that will be observed in cases of liver cirrhosis are:
- Decreased liver size.
- Firm consistency: due to the deposit of connective tissue.
- Nodular surface: due to the formation of regeneration nodules.
Causes of cirrhosis in dogs
Among the causes that can cause cirrhosis in dogs, there are:
- Anticonvulsant treatments: fundamentally associated with the administration of phenobarbital, a powerful hepatotoxic agent.
- Chronic hepatitis: In the dog, chronic hepatitis can be caused by infectious agents (such as canine adenovirus type 1, Ehrlichia canis, or Leishmania infantum), toxins such as copper, aflatoxins and drugs.
- Poisoning by plant alkaloids: much more common in herbivores than in carnivores. You may be interested in reading this article about herbivorous animals: examples and curiosities.
- Biliary obstruction or chronic cholestasis.
- Secondary passive hepatic congestion: leading to Congestive Heart Failure. Get more information about heart failure in dogs in this other post on our site that we recommend.
Symptoms of cirrhosis in dogs
In the early stages of the process, dogs may remain asymptomatic or show nonspecific clinical signs such as vomiting, diarrhoea, polyuria, polydipsia, anorexia, weight loss, apathy and/or depression.
However, once the functional reserve capacity of the liver is exceeded, clinical signs suggestive of liver disease will appear. Generally, the structural and functional alteration of the cirrhotic liver leads to liver failure characterized by the following clinical picture:
- Ascites: abdominal dilation due to the presence of free fluid in the abdomenWhen the liver is unable to maintain albumin levels in the blood, there is a decrease in oncotic pressure that causes ascites. Here you can find more information about Ascites in dogs: causes and treatment.
- Jaundice: yellowing of the mucous membranes caused by excess bilirubin(yellow pigment) that is deposited on tissues. In dogs, it is usually initially detected at the level of the sclera. If you have questions about Jaundice in dogs: causes, symptoms and treatment, read this other post on our site where we give you more information.
- Hepatic encephalopathy: is a neurological condition that is caused by the accumulation in the blood of substances neurotoxic substances not metabolized by the liver, mainly ammonia. Signs that may be seen in these dogs include altered level of consciousness (lethargy, stupor, and eventually coma), weakness or ataxia, pressure of the head against the wall or floor, circling, and seizures. Here you can read more about hepatic encephalopathy in dogs: symptoms and treatment.
- Acquired portosystemic shunts: consists of the formation of vessels that abnormally connect the portal vein with the vena cava. It occurs as a consequence of secondary portal hypertension to cirrhosis.
- Bleeding tendencies: occurs as a result of decreased synthesis of coagulation factors, platelet function and of the absorption of vitamin K. See more information about Vitamin K for dogs: dosage and uses, here.
- Photosensitization: occurs when photosensitive substances are not inactivated in the liverand are deposited in the skin, giving rise to an inflammatory and necrotic process of the epidermis.
- Hepatocutaneous syndrome: characterized by the appearance of lesions in the much-cutaneous junctions and foot pads of dogs. It is produced by an alteration in epidermal maturation secondary to the deficiency of essential amino acids that occurs during liver failure.
Diagnosis of cirrhosis in dogs
The diagnosis of cirrhosis in dogs should follow the following scheme:
- Medical history and general examination: Special attention should be paid to the presence of clinical signs associated with liver failure, described in the section previous.
- Blood test with liver profile: Values such as total protein, albumin, liver enzymes (ALT, GGT and phosphatase) should be measured alkaline), ammonia, glucose and bile acids. Check here the Normal glucose levels in dogs.
- Abdominal ultrasound: an image suggestive or compatible with cirrhosis can be observed, characterized by the presence of hyperechoic nodules (of a whitish color in the ultrasound image) that correspond to the regeneration nodules typical of this process. However, this image is also compatible with the presence of a liver tumor, so ultrasound does not allow a definitive diagnosis.
- Abdominal x-ray: The purpose of the x-ray is to provide information about the size of the liver, since ultrasound usually gives a somewhat subjective. In cirrhosis the liver will be decreased in size.
- Biopsy and histopathology: The sample can be taken percutaneously (using biopsy needles) or surgically (via laparotomy or laparoscopy). In the histopathological analysis, it will allow the definitive diagnosis of cirrhosis by detecting a deposit of connective tissue (fibrosis) that delimits the regeneration nodules.
Treatment of cirrhosis in dogs
Despite the fact that cirrhosis is an irreversible process, it is important to establish adequate treatment in order to prevent the progression of fibrosis and control the signs and complications associated with this process. Specifically, the treatment of cirrhosis in dogs is based on the following points:
- Slowing down the progression of fibrosis: antifibrotics such as colchicine can be administered, although there are no studies showing their efficacy.
- Dietary Management: Good nutritional management is essential to maintain body condition in dogs with liver disease. Provide a highly digestible diet, rich in easily assimilated carbohydrates and low in fat. It will only be necessary to restrict protein levels in dogs with hepatic encephalopathy. In cases of copper poisoning, the level of copper in the diet should also be restricted. Here we leave you this other article about the Diet for dogs with liver problems from our site.
- Treatment of complications: in animals with ascites, diuretics such as furosemide or spironolactone should be administered; In cases of severe ascites, an abdominocentesis should be performed to evacuate the abdominal fluid. In dogs with hepatic encephalopathy, the production and absorption of toxins in the intestine should be prevented by the use of laxatives (such as lactulose) and oral antibiotics.
- Support treatment: as a supplement, hepatoprotectors and antioxidants such as ursodeoxycholic acid, vitamin E or silymarin can be administered. We recommend that you take a look at this article on Vitamin E for dogs: dosage and uses.
