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. Mention is made of ammonia, which produces urea, although there are also other toxins such as mercaptans, skatoles, indoles, and short-chain fatty acids.
This accumulation of toxins in the blood reaches the central nervous system, affecting neurons and neurotransmitters and causing neurological symptoms. It is usually due to a liver problem that prevents proper metabolism, although it can also occur as a result of inadequate vascular communication or an enzyme deficiency of the urea cycle.
Continue reading this article on our site to find out what is hepatic encephalopathy in dogs, its symptoms, diagnosis and treatment.
What is hepatic encephalopathy
Hepatic encephalopathy arises from a metabolic disorder in the dog's liver that results in the accumulation of toxic compounds in the blood When these toxins reach the central nervous system, triggering neurological signs
You should know that the liver is a key organ in the body, as it is responsible for metabolizing and cleaning the blood of substances and waste products that come from cell metabolism. Specifically, the urea cycle takes place in the mitochondria of liver cells. In this cycle, excess ammonia is converted into useful amino acids or into urea that will form part of the urine in the kidneys.
For this reason, when this "cleaning point" fails for different reasons, waste compounds and toxins that should be eliminated through urine accumulate in the blood. Not doing so is how they reach the brain, damaging its cells and causing changes in neurotransmitters. The consequence is the signs of encephalopathy.
Among the toxic compounds that accumulate, ammonia (NH3) stands out and, generally, its accumulation derives from liver disease. Other toxic compounds that can cause this encephalopathy are indoles, mercaptans, skatoles and short-chain fatty acids.
Causes of hepatic encephalopathy
Hepatic encephalopathy in dogs encompasses causes resulting from vascular abnormalities, urea cycle enzyme deficiencies, or liver damage. Among them we can find:
- Hepatic cirrhosis.
- Hepatobiliary disease.
- Poisoning, medications or infections causing liver failure.
- Portosystemic shunt intra or extrahepatic.
- Chronic Hepatitis.
- Arginosuccinate synthetase enzyme deficiency, which can cause hepatocellular destruction and hyperammonemia.
Hepatic encephalopathy symptoms in dogs
Hepatic encephalopathy in dogs can be divided into four stages from least to most severe:
- At the beginning of the problem, the dog will be disoriented, without appetite, irritable and clumsy.
- As the picture worsens, the dog will present head pressing, which is the impact of the head against the wall, walking in circles, ataxia, lethargy and even blindness.
- When the picture is more serious, the dog will be confused, with stupor, incoordination, inactivity, hypersalivation,seizures and even assaults.
- Finally, the accumulation of toxins causes so much damage that the dog goes into a coma and death occurs.
- Non-neurological signs may also be seen, such as weight loss, polyuria-polydipsia, vomiting, diarrhea and ascites in more advanced cases of liver disease. Puppies with congenital portosystemic shunts are less than a year old, are usually the youngest of the litter, and have a poor overall appearance.
Canine hepatic encephalopathy diagnosis
The diagnosis must be based on the animal's symptoms, the caregiver's anamnesis and the complementary diagnostic tests. Neurological symptoms with signs of weakness and weight loss, with or without liver signs, make this problem very likely, but the following tests should be done to confirm it:
- CBC: Will show mild to moderate non-regenerative anemia.
- Blood biochemistry: alterations such as hypoalbuminemia, decreased urea, increased ammonia, increased AST, ALT and alkaline phosphatase and increased bilirubin if liver failure is very severe. Some dogs may exhibit fasting hypoglycemia and hypercholesterolemia.
- Urinalysis: Urine may be dilute and contain ammonium biurate crystals.
On the other hand, to diagnose a portosystemic shunt, fasting and postprandial levels of ammonia and bile acids should be measured. If shunted, these acids will increase their postprandial levels. If the levels increase by more than 100 umol/L in a puppy, it is a strong indication that he has a congenital portosystemic shunt. The diagnosis is confirmed with abdominal ultrasound and Doppler ultrasound to locate the suspicious vessel and the communication and direction of blood flow.
Treatment of hepatic encephalopathy in dogs
In the face of hepatic encephalopathy you have to act fast Many dogs will have to stay in the veterinary center, where they will putfluid therapy and oxygen Once the dog has been detoxified, the disease that caused the hepatic encephalopathy must be treated so that the organism recovers and it does not happen again.
Treatments range from medication to surgery, especially in portosystemic shunt. When the dog has an affected liver, you should reduce the protein intake, to reduce the work of the liver, but not lower than 2.1 g of protein per kg weight of the dog per day.
