The liver is the most important organ and the clearing house of the dog’s body. The fact that the entire blood supply passes through the liver to be detoxified makes it more susceptible to many diseases. Causes of liver diseases in dogs include genetics, drug use, dietary and environmental toxins, poor or improper nutrition, bacterial or fungal or viral infections, trauma, cancer and Cushing’s disease. In dogs, liver diseases include hepatic encephalopathy, hepatic lipidosis or fatty liver, abscesses and acute hepatic failure.
Cushing’s syndrome is an endocrine disease caused by the excessive production of hormones by the adrenal gland. The underlying cause may be a problem with disorders associated with either the adrenal or pituitary gland, which controls the production of adrenal hormones. Canine Cushing’s disease is primarily associated with pituitary gland problems.
The diagnosis of Cushing’s disease in dogs can be very frustrating. As the disorder occurs mostly in older dogs, who are often afflicted with more than one problem, the challenge becomes harder. Many times, dogs show obvious signs of this disorder, but lab reports do not reveal any specific data. Repeated lab work may be required at times to confirm the hypothesis. The symptoms are also so vague that many other diseases may have to be ruled out first, including diabetes, vascular tumor of the adrenal gland, and liver disease.
Liver failure can also be caused by Cushing’s syndrome, as both are linked with each other through elevated levels of cortisone. Cortisone is one of the end products of steroidgenesis, a complex process that starts with the synthesis of cholesterol. During the process, various steroid hormones including glucocorticoids, cortisone and cortisol are generated through the transformation of other steroids.
The liver is very sensitive to glucocorticoid drugs. It is also sensitive to the long-term internal overproduction of cortisone that is normally produced by the adrenal glands, and is prone to develop typical lesions. Liver disease causes damage to each liver cell one by one. As more cells are damaged, overall liver functioning is affected, which ultimately leads to liver failure.
The symptoms of Cushing’s disease and liver disease often overlap each other. Polyuria (excessive urination), polydipsia (increased thirst), and a potbellied appearance are associated with both the conditions. If the liver is affected due to Cushing’s disease, the lesions may prompt typical symptoms associated with liver disease. In the event the liver is damaged, jaundice, anemia, light- colored stools and bleeding disorders are some of the symptoms that may be seen in dogs with Cushing’s.