Diabetes (Hepatopathy) in Dogs

Several types of vacuolar hepatopathy can occur in dogs with diabetes mellitus. A vacuole is a small cavity within the liver cell. Vacuoles occur when liver cells become enlarged and take on another cell, either a glycogen molecule, or a combination of glycogen and lipid molecules (most common with diabetes). Since diabetes makes the body less able to process glucose, fat stored in the adipose tissue is released to compensate for the perceived lack of carbohydrate nutrition. When more lipids are released than the liver can metabolize, they are stored in the hepatocytes (liver cells). Too many fat enlarged cells increase the size of the liver, reducing bile production and other hepatic functions. This is called hepatic lipidosis or fatty liver disease. It is more common in cats, but it is also found in toy breeds of dogs. Many dogs with unregulated diabetes have some degree of liver dysfunction from fatty changes to the liver, although they may have few or mild symptoms. In some cases, the fat in the liver can also rupture and be released into the bloodstream where it may cause circulatory blockage. Fatty liver disease can usually be reversed with better diabetes regulation. Dogs with diabetes may also have another liver disease called hepatocutaneous syndrome. This is a glycogen-like vacuolar hepatopathy that presents itself with skin lesions. Lesions can appear several months before symptoms of liver failure become apparent. The relationship to diabetes is not well understood, but both diseases often occur together. Dogs with hepatocutaneous syndrome have low blood levels of amino acids and are frequently resistant to insulin. Injection of amino acids can sometimes help, but treatment options for this disease are limited.

Liver disease or hepatopathy is more common in dogs with diabetes. Lack of glucose absorption causes lipid mobilization which leads to fat accumulation in the liver. This is called fatty liver disease, or hepatic lipidosis. Additionally, hepatocutaneous syndrome, a form of liver failure accompanied by skin lesions, frequently occurs in combination with diabetes.

If dogs don’t have symptoms, fatty changes to the liver may still be diagnosed with a blood test that shows reduced liver function. Any of the following symptoms should be evaluated by a veterinarian.

• Weight loss
• Thirst
• Lethargy
• Jaundice (yellowish tone most visible in the gums and eyes)
• Depression
• Hypersalivation
• Vomiting
• Diarrhea
• Skin lesions on the paws, belly or face

Types

The following types of liver disease are most frequently associated with diabetes.

• Hepatic lipidosis (fatty liver disease) which is liver disease from fat accumulation in the liver; typically a feline disease, but dogs with diabetes often have a milder version
• Vacuolar hepatopathy, a liver disease in which hepatocytes become enlarged, usually by the addition of glycogen and/or lipid molecules
• Hepatocutaneous syndrome (also called superficial necrolytic dermatitis), an idiopathic liver disease frequently found in combination with diabetes

Diabetes and related hepatopathy are more common with the following conditions.

• Obesity
• Pancreatitis
• Hyperadrenocorticism (Cushing’s Disease)
• Medication use (steroids,progesterone)
• Genetically more likely in some breeds: Beagles, Miniature Poodles, Dachshunds, Schnauzers, Cairn Terriers, Australian Terriers, Samoyeds, Keeshondens
• Un-spayed females can develop temporary diabetes during diestrus or pregnancy
• More common in older dogs

Blood and urine tests can diagnose diabetes. Dogs with a fasting blood sugar above 120 are considered diabetic. Excess glucose is also excreted in the urine, so diabetic dogs commonly have glycosuria also. Blood tests will often diagnose liver dysfunction that is combined with diabetes and can be especially helpful with dogs that aren’t showing symptoms. Increased ALP (alkaline phosphatase) is the one of the important indicators of liver disease, as well as bile and albumin levels in the blood. Dogs may also have poikilocytosis or spiculated red blood cells due to abnormal lipid content in the cell membrane. A blood coagulation test may be necessary to evaluate the chance of blood clots.

The veterinarian  will usually order an x-ray and/or an ultrasound of the abdomen in the case of liver disease. This will often show an enlarged liver with rounded edges, and sometimes lesions or nodes in the later stages. A so-called “Swiss cheese pattern” is often observed on an ultrasound with vacuolar hepatopathy. A biopsy of the liver will definitively diagnose the presence of excess fat and/or glycogen.

Dogs with diabetes-related hepatocutaneous syndrome will likely have similar signs of liver dysfunction on a blood test as well as lower than normal levels of amino acids. Depending on the stage of the disease, magnetic imaging often shows a similar vacuolar pattern. The veterinarian will examine your dog’s skin lesions and take a skin biopsy to rule out other causes such as infection.

In most cases of fatty liver disease, regulating diabetes will reduce the related hepatopathy. Dogs are usually prescribed insulin several times a day and sometimes oral medication as well. Diet and weight loss are also recommended, depending on the cause of diabetes. Dogs with diabetes need a diet high in fiber. With hepatic lipidosis, fat and carbohydrate intake will need to be limited and dogs should eat nutrient rich proteins to avoid lipid mobilization. If your dog is already on a treatment for diabetes, the veterinarian may need to increase insulin doses and further restrict your dog’s diet.

Dogs with skin lesions are usually given intravenous amino acid concentration. There is some risk of side effects with this treatment and the veterinarian will need to monitor your dog closely. A similar high protein diet is recommended with the addition of amino acid supplements. Response to treatment is sometimes limited, especially since the related diabetes often becomes insulin resistant.

Dogs that have significant liver failure may need supportive treatments. Anti-emetics or intravenous fluids could be necessary. Anticoagulants will be prescribed if blood clots are an issue. Other serious complications of diabetes, like ketoacidosis, may also need immediate supportive treatment.

Dogs with carefully managed diabetes can make a complete recovery from fatty liver disease. Diabetes is a treatable condition in dogs, but it may require significant diet and life-style changes. You will need to check your dog’s blood sugar several times a day and administer insulin injections. Your dog will need to follow the recommended diet strictly for several months for liver function to improve. Increased exercise may also be necessary to help with weight-loss. Frequent check-ups will help the vet monitor your dog’s progress.

Dogs with a combination of diabetes and hepatocutaneous syndrome have a guarded outlook. If the skin lesions improve with treatment, there is some chance of recovery, but if insulin resistant diabetes persists it will be hard to manage with medication. The veterinarian will evaluate your dog’s outlook upon diagnoses.