A small liver, microhepatica, in a dog usually indicates the pet is suffering from chronic active hepatitis. This is a progressive inflammation of the dog's liver and leads to all normal liver tissue eventually being replaced by scar tissue. The cause of the disease is not known in many cases, but may be induced by canine hepatitis virus, leptospirosis, other diseases, toxicity from certain drugs, or genetics.
The condition is seen most often in Bedlington terriers, West Highland white terriers, Doberman pinschers, cocker spaniels and Skye terriers. It usually occurs in middle-aged animals, and female dogs seem to be at a greater risk than males. However, chronic active hepatitis can occur in any breed.
Symptoms of chronic active hepatitis include anorexia, lethargy, weight loss, vomiting, diarrhea, excessive urinating, excessive drinking, fluid in the abdominal cavity, jaundice and an increased tendency to bleed.
Your veterinarian will employ several diagnostic tools to determine your pet's condition. These may include a complete blood count, biochemical profile, urinalysis, testing of the ammonia level, blood clotting profile, abdominal X-rays, abdominal ultrasound and, possibly, a liver biopsy. It is during abdominal X-rays that your veterinarian is likely to note an enlarged liver, hepatomegaly, or a small liver, microhepaticia. Both indicate chronic active hepatitis.
If your dog is diagnosed with chronic active hepatitis, expect that he will be hospitalized. He will be given fluid and electrolytes to correct imbalances and dehydration caused by vomiting, diarrhea and not eating. The veterinarian will likely prescribe antibiotics, steroids, drugs to stimulate the liver and a vitamin K supplement.
Because chronic active hepatitis basically means your pet is in liver failure, full recovery is not likely. Your pet will likely be on a special diet and medications for the duration of her life. If the underlying cause of your dog's condition can be determined and treated, such as a particular drug that is causing her illness, prognosis is considered fair. In other cases, dogs generally survive from several months to three years after diagnosis.
While chronic active hepatitis is the most likely cause of your dog's small liver, other conditions can have similar symptoms. Some of these include liver cancer, infectious canine hepatitis, hepatotoxins, chronic hepatitis due to a bacterial infection, pancreatitis, pancreatic cancer, intestinal inflammation and primary gallbladder disease.