Acute Hepatic Failure in Dogs
Acute hepatic failure in dogs refers to the abrupt decline of at least 70 percent of the liver’s function caused by sudden and extensive hepatic necrosis, or tissue death within the liver.
Symptoms
Symptoms of liver failure in dogs, whether stemming from primary or secondary hepatobiliary disorders, typically involve hepatic necrosis to varying degrees. Although acute liver failure resulting from severe hepatic necrosis is rare, it can manifest in several systemic failures:
Digestive system: vomiting, diarrhea, presence of blood in stool (hematochezia) Nervous system: hepatic encephalopathy (brain dysfunction linked to liver failure) Hepatobiliary system: involving the liver and gallbladder; symptoms may include jaundice, necrosis (cell death) of liver and bile duct cells Renal system: potential injury to kidney tubules from toxins or metabolites Immune/Lymphatic/Hematological: disruptions in blood and lymphatic systems, which may contribute to clotting complications.
Causes
Liver failure in dogs is primarily triggered by infectious agents or toxins, inadequate perfusion of fluids into the liver and surrounding tissues, hypoxia, hepatotoxic drugs or chemicals, and excessive heat exposure. The onset of necrosis ensues, causing the loss of liver enzymes and hindering liver function, eventually leading to complete organ failure.
Furthermore, acute liver failure can arise from significant metabolic disorders affecting protein synthesis (including albumin, transport proteins, procoagulant and anticoagulant factors), glucose absorption, and abnormalities in metabolic detoxification processes. Failure to promptly address this condition can culminate in fatality.
Diagnosis
Acute liver failure in dogs is diagnosed through a comprehensive assessment including hematology, biochemistry analysis, urine analysis, biopsy, and imaging such as ultrasound or radiology.
Hematology, biochemistry, and urine analyses will examine for:
- Anemia
- Abnormalities in thrombocytes (blood platelets promoting clotting)
- Elevated liver enzyme activity or leakage of liver enzymes into the bloodstream, indicating liver damage. Tests will check for alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzymes, increased alkaline phosphatase (ALP), and decreased levels of aminotransferases.
- Impaired protein synthesis
- Low blood sugar
- Normal to low blood urea nitrogen (BUN) levels
- Presence of bilirubin in the urine
- Presence of ammonium urate crystals in the urine
- Presence of sugar and granular casts in the urine, suggesting internal tubular injury from drug toxicity, such as NSAIDs.
Lab tests will assess:
- Elevated total serum bile acid (TSBA) concentrations, indicating liver insufficiency. However, TSBA findings may lose significance if non-hemolytic jaundice has already been confirmed.
- High plasma ammonia concentration, in conjunction with high TSBA concentrations, indicating hepatic insufficiency.
- Abnormalities in blood platelets and coagulation factors.
- Tissue necrosis and cell pathology, confirmed or negated by biopsy results, which also identify underlying conditions.
Imaging tests will observe:
- Enlarged liver and other hepatic abnormalities on X-rays and ultrasound, including conditions indirectly related to the liver.
Treatment
Treating a dog with liver failure requires hospitalization as a crucial step. Fluids and electrolytes, along with colloid replacements essential for proper thyroid function, and oxygen supplementation, constitute vital elements of treatment and care. Restricted activity is prescribed to allow the liver time to regenerate. For highly unstable patients, catheter feeding is recommended, while stable patients are advised enteric feeding in small amounts directly into the intestines. A normal protein diet supplemented with vitamins E and K is recommended.
Common medications used for liver failure include antiemetics, drugs for hepatic encephalopathy (brain disease, with or without edema), hepatoprotectants to decrease aminotransferase activity, coagulopathy drugs, and antioxidants.
Prevention
To prevent acute liver failure in dogs, one can opt for vaccinating them against infectious canine hepatitis virus, which causes acute liver infection. Additionally, it’s important to refrain from using drugs containing hepatotoxins, as they pose a risk to the liver’s health.
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