Hepatic Encephalopathy in Cats

The liver is critical for detoxifying blood from the digestive system. When blood fails to flow properly to the liver to be filtered or when the liver is not performing the required function of filtering toxins and harmful substances from the blood, toxins can enter the animal’s circulation system. Hepatic encephalopathy results when substances such as ammonia and other neurotoxins build up in the circulation system cause disorders of the nervous system. 

Hepatic encephalopathy is potentially life-threatening and requires immediate treatment by a veterinarian.

Hepatic encephalopathy is a disorder of the nervous system that results from poor liver function.

Symptoms of hepatic encephalopathy include both neurological symptoms and symptoms of liver failure.

• Jaundice
• Unusual thirst or urination
• Vomiting and diarrhea
• Constipation
• Behavioral changes, including aggression
• Restlessness and pacing
• Neurological symptoms such as circling and head pressing
• Impaired balance
• Weakness
• Collapse
• Visual impairment/blindness
• Seizures
• Coma
• Cerebral edema in severe cases

Causes of hepatic encephalopathy may be congenital and manifest within the first 12 months of life. The condition may also be acquired, which can occur at any age.

Congenital liver impairment is usually characterized by impaired circulation to the liver. This can occur when a shunt occurs in the circulation system carrying blood from the digestive system to the liver. This results in blood from the digestive system not being filtered by the liver before re-entering the bloodstream.

An impaired liver can also be caused by or aggravated by the following factors:

• Drugs, especially anesthetics or sedatives
• Toxins in the environment
• Viral infection
• Bacterial infection, especially of the digestive system
• Dietary factors, such as low sodium, potassium or blood sugar
• Constipation leading to a buildup of bacterial flora in the gut
• Gastrointestinal bleeding

It will be critical that a complete history of the cat be provided by the pet owner to the veterinarian. This history should include information on parentage and development in a young animal to determine the likelihood of congenital factors. You should also communicate exposures and medical history to narrow down factors that may have contributed to an acquired liver disorder. Your veterinarian will want to know details about the onset of symptoms, your cat’s diet, and details of their recent urinary and fecal elimination.

Your veterinarian will order complete blood and urine tests to rule out conditions such as damaged kidneys and identify impaired liver function. In addition, x-rays and ultrasound of the liver may be ordered that will help reveal liver malfunction. In some cases, a sample of the liver by aspiration or biopsy may be taken for tissue testing. A CT scan or MRI may be used to discover shunts and structural anomalies or rule out tumors.

Your vet will hospitalize your cat to provide supportive care and treat the underlying liver condition.

Supportive Care

Your veterinarian may administer intravenous (IV) fluids to counteract dehydration. In this case, your pet will be closely monitored to ensure an imbalance of electrolytes does not occur and that your cat is hydrated appropriately.

Medication

Medication to counteract neurotoxins in the circulation system will be provided as appropriate. Your veterinarian will avoid the use of sedatives and other drugs that require liver processing and will aggravate your pet’s condition. 

Gastrointestinal

Antibiotics may be administered to treat infection in the gastrointestinal tract and reduce harmful or excess bacteria. In addition, your veterinarian may administer enemas to remove bacteria from the colon if necessary.

Once recovered, a modified diet aimed at helping liver function and probiotic yogurt to improve gut functioning will be prescribed. The diet will balance protein requirements and minerals such as zinc, which may be a factor in impaired liver functioning.

Surgical

In the case a shunt is present, surgery may be performed to correct the shunt and restore proper circulatory functioning.

A full recovery depends on the successful treatment of the underlying liver disorder and the extent of neurological impairment. A modified diet may be prescribed to your cat to ensure improved liver functioning. Factors that contributed to the liver disorder should be avoided. You should monitor your cat to ensure that any return of liver disorder or neurological disorder symptoms are recognized and reported immediately to your veterinarian.