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Icterus in Dogs

The term icterus (or jaundice) denotes a yellow discoloration of mucous membranes of the gums, nostrils, genitals, and other areas due to a high concentration of bilirubin, a normal bile pigment formed as a result of a breakdown of hemoglobin present in red blood cells (RBCs).

If there is an increased rate of RBC breakdown, as occurs in some diseases, abnormally high levels of bilirubin will form. These high levels of bilirubin cannot be excreted at a normal rate, and thus, accumulates in tissues. Bilirubin levels may also increase in conditions where normal excretion of bilirubin is hampered due to some disease (e.g., cholestasis), in which bile cannot flow from the liver to the duodenum (first section of intestine) due to some mechanical obstruction or neoplasia.

Higher concentrations of bilirubin are toxic and may cause discoloration of the skin (i.e., jaundice), liver and kidney injury, and may also affect brain tissue. All breeds of dogs can be affected.

Symptoms and Types

• Vomiting
• Diarrhea
• Lethargy
• Fever
• Abdominal pain
• Loss of appetite (anorexia)
• Paleness
• Yellowish discoloration of the skin
• Change in color of urine and feces (orange colored)
• Increased frequency (polyuria) and volume of urine
• Increased thirst (polydipsia) and consumption of water
• Mental confusion in advanced cases
• Weight loss
• Bleeding (especially in dogs with advanced liver disease)

Causes

• Diseases, toxins, drugs leading to increased destruction of RBCs
• Incompatible blood transfusion
• Systemic infections impairing processing of bilirubin in liver
• Collection of large volume of blood inside body cavity
• Inflammation of liver (hepatitis)
• Tumors
• Cirrhosis
• Massive damage to liver tissue (e.g., due to toxins)
• Obstruction in secretion of bilirubin due inflammation of pancreas, presence of tumor, stones, or parasites.

Diagnosis

Your dog’s veterinarian will take a detailed history from you and perform a complete physical examination on your cat. Routine laboratory tests including: complete blood count, biochemistry profile and urinalysis will be conducted. These tests will reveal very valuable information for the initial diagnosis. Complete blood count tests may reveal changes in RBC structures, changes pertaining to underlying infections like severe anemia, blood parasites, and abnormally low levels of platelets (cells responsible for blood clotting). The biochemistry profile, meanwhile, may reveal abnormally high levels of liver enzymes pertaining to liver injury. And urinalysis will show abnormally high levels of bilirubin in urine.

There are more specific tests available for further diagnosis, including underlying causes. Radiographic studies will help in the determination of structure and size of the liver, which is the central organ of importance in this disease. These X-rays often find the liver enlarged, reveal the presence of a mass or tumor, the enlargement of the spleen in some cases, and foreign bodies. Thoracic X-rays may reveal metastasis if a tumor is the cause. Ultrasound will also be performed, enabling your veterinarian to evaluate the liver structure in detail, helping to distinguish liver disease from an obstruction of biliary tract, as well as differentiating a tumor from a mechanical obstruction.

Additionally, the veterinarian may decide to take a sample of liver tissue with the aid of ultrasound for a more detailed evaluation. Liver tissue samples may be taken through a needle or during surgery, which may be performed for confirmatory diagnosis and treatment.