Hepatic Lipidosis in Cats
Hepatic lipidosis, known commonly as fatty liver, is one of the most common severe feline liver diseases in cats. The liver's main functions include protein synthesis, the production of chemicals necessary for digestion, and the detoxification of the body. The liver also plays an important role in metabolism, the emulsification of fats, the production of coagulation factors (necessary for blood clotting), and in the decomposition of red blood cells. The liver is of such importance to the body, carrying out so many complex functions, that there is no way to compensate for the loss of the liver when it fails.
Normally, when a body is undernourished or starved, the body automatically moves fat from its reserves to the liver to be converted into lipoproteins for energy. Cat's bodies are not designed to convert large stores of fat, so when a cat is in starvation mode, the fat that is released to the liver is not processed efficiently, resulting in a fatty and low functioning liver. As the fat accumulates in the liver it becomes swollen and turns yellow. Because it is not able to process red blood cells efficiently, the yellow pigment that makes up a portion of the red blood cell is released into the bloodstream, causing a yellowing of the eyes. If not treated promptly, hepatic lipidosis can lead to various complications and eventually death.
Cats have high nutritional requirements for proteins, as they are strictly meat eaters, so that a lack of protein or inability to process proteins will quickly develop into malnutrition. Profound lack of appetite and stress are also related to hormonal disturbances, which can also affect fat metabolism and cause fat mobilization from other parts of the body to the liver – with the same results described here. This condition also frequently occurs in conjunction with illness, periods of stress, changes in diet, diabetes, kidney disease, cancer, aggressive weight loss attempts by owners, and being lost (away from home and meals).
Found worldwide, this primarily affects middle-aged cats.
Symptoms and Types
- Prolonged anorexia – often of several week duration
- Rapid weight loss
- Muscle wasting
- Downward flexion of head and neck
- Jaundice (e.g., yellowing of eyes)
- Drooling of saliva
- Cat may collapse in later stages
- Other symptoms will be related to concurrent, underlying disease
- In most cases the exact cause may remain unknown
- Liver disease
- Inflammation of pancreas (pancreatitis)
- Kidney disease
- Other diseases
- Important risk factors are obesity, stress, a change in living arrangements, getting lost, loss of appetite, and generalized diseases.
You will need to give a thorough history of your cat's health, onset of symptoms, and possible incidents that might have preceded this condition. The history you provide may give your veterinarian clues as to which organs are causing secondary symptoms, and what underlying condition might have led to the diseased liver.
Routine laboratory testing will include a complete blood count, biochemistry profile, and urinalysis. Blood tests may reveal red blood cells of abnormal size (poikilocytosis), and destruction of red blood cells (hemolysis). There may also be an increase in the enzyme, alkaline phosphatase (ALP), which can be indicative of liver failure. The biochemistry profile may reveal abnormally high levels of liver enzymes and bilirubin levels, and the urinalysis may also reveal high concentration of bilirubin in the urine. Because the liver plays an important role in blood clotting and abnormalities related to blood coagulation may also be evident in affected cats.
Imaging tools include radiographic and ultrasonography studies for examining the abdomen, which may reveal an increase in the size of the liver, as well as to make a detailed evaluation of the liver's architectures and abnormalities. In order to confirm a diagnosis, your veterinarian will need to take a sample of the liver tissue, either through biopsy or needle aspirate, in order to see the liver cells and related abnormalities, including accumulation of fat droplets in these cells – an affirmation of lipidosis.