Hepatic encephalopathy in dogs consists of an accumulation of toxins in the blood that should have been metabolized by the liver and eliminated by the kidney. The main problem is rising ammonia levels. This produces urea and other toxins that are improperly metabolized. This accumulation of toxins in the blood reaches the central nervous system, affecting neurons and neurotransmitters and causing neurological symptoms. It is generally due to a liver problem that prevents proper metabolism, although it can also occur as a result of improper vascular communication or an enzyme deficiency in the urea cycle.
Keep reading this article to learn more about hepatic encephalopathy in dogs. We will specifically analyze the causes, symptoms and treatment so that you can know what to do if your dog develops this disease.
What is hepatic encephalopathy?
If a disease is liver, it means that it is related to the liver. However, encephalopathy is a condition that causes damage to the brain. The two are related because it is a metabolic disorder of the dog’s liver that results in the accumulation of toxins in the blood. When these toxins reach the central nervous system, they travel to the brain and trigger signs of neurological problems.
Since the liver is a vital organ, its effectiveness affects the health of the entire organism. It is responsible for cleaning and detoxifying the dog’s blood from the waste produced during the metabolism of the cells. Specifically, the urea cycle takes place in the mitochondria of liver cells. During this cycle, excess ammonia is converted to useful amino acids and urea, the latter of which is converted to urine in the kidneys.
For this reason, when the liver fails for any reason, its detoxifying function suffers. Waste compounds and toxins build up in the blood that otherwise should have been removed. Since they are not eliminated, they end up in the brain: they damage cells and cause changes in neurotransmitters.
Causes of Hepatic Encephalopathy in Dogs
In dogs, the disease encompasses causes derived from vascular abnormalities, enzyme deficiencies in the urea cycle, or liver damage. Among them we can find:
- Hepatic cirrhosis.
- Hepatobiliary disease.
- Poisoning, medications, or infections that cause liver failure.
- Intra or extrahepatic portosystemic shunt.
- Chronic hepatitis
- Arginosuccinate synthetase enzyme deficiency.
Symptoms of hepatic encephalopathy
Hepatic encephalopathy in dogs can be divided into four stages. The stage a dog is in is determined by the severity of the disease:
- At the onset of the problem, the dog will be disoriented, lose his appetite, become irritable, and may be clumsy.
- As the clinical picture worsens, the dog will notice pressure on the head. You will notice this from the compulsive act of pressing his head against a hard surface such as a wall. They can also walk in circles, develop ataxia, lethargy, and even go blind.
- When the condition is more serious, the dog will be confused. We can see stupor, incoordination, inactivity, hypersalivation, seizures and even aggression.
- Sometimes the accumulation of toxins causes so much damage that the dog falls into a coma and death occurs.
There are also other non-neurological signs of hepatic encephalopathy in dogs, including weight loss, polyuria-polydipsia, vomiting, diarrhea, and ascites.
Diagnosis of canine hepatic encephalopathy
The diagnosis should be based on the animal’s symptoms, the anamnesis (medical history) and certain tests to confirm it:
- CBC (complete blood count): will show mild to moderate non-regenerative anemia.
- Blood chemistry: Changes such as hypoalbuminemia, decreased urea, increased ammonia, increased AST, ALT, and alkaline phosphatase, and increased bilirubin can be seen if liver failure is very severe. Some dogs may have fasting hypoglycemia and hypercholesterolemia.
- Urinalysis: Urine may be dilute and have ammonium biurate crystals.
Treatment of hepatic encephalopathy in dogs
Many dogs will have to remain in the veterinary center where they are treated, where they will be administered fluid therapy and oxygen. Once detoxified, the disease that caused the hepatic encephalopathy must be treated so that the body recovers and does not recur.
Treatments range from medication to surgery, especially portosystemic shunting. When the dog has an affected liver, protein intake should be reduced to reduce stress on liver function.