Complete Care for Your Aging Cat - Amy Shojai [114]
LIVER DISEASE
The liver has multiple functions, from screening out toxins and metabolizing drugs, to creating necessary nutrients and enzymes. Liver disease can be any condition that interferes with one or more of these processes, and it may develop at any age.
Fortunately, the liver has quite a bit of built-in redundancy, and only a small portion of the organ needs to function to maintain the cat’s health. “After some insults, it’s fully capable of regenerating to its original size,” says Cynthia R. Leveille-Webster, DVM, an internist at Tufts University. A lifetime of exposure to toxins, stress, and damage means old cats are more prone to liver problems. Some diseases damage the liver so badly it isn’t able to recover.
Hepatic lipidosis is the most common liver disease of cats, and cholangiohepatitis is the second most common, says Dr. Davenport. “Occasionally you see cats that have both diseases simultaneously.”
Dr. Schulman says it’s a myth that only obese cats get hepatic lipidosis. Once the cat stops eating, fat is released into the blood as a source of nutrition. Because the liver cells store fat, they quickly become overwhelmed and are no longer able to function. “About ten years ago, the disease was invariably fatal because doctors did not know how to treat it. These days, most cases survive,” says Dr. Schulman.
There are also three forms of inflammatory liver disease (hepatitis) that affect cats. The acute form is usually caused by bacterial infection, says Dr. Webster. The two others are so similar they can only be told apart by examining cells under the microscope. One tends to be a disease of young to middle aged cats. Lipacidic hepatitis, or lipacidic cholangiohepatitis most commonly affects aged cats, says Dr. Webster. Some studies indicate that even when they don’t become sick from it, many old cats have this mild to moderate inflammation in their livers. “My own cat has it,” she says. “It’s rare that it requires intervention and therapy.”
Signs can be confusing because liver disease mimics other illnesses, and often the sick cat has problems in other body systems at the same time with symptoms that overlap. “Cats that have liver disease can actually get concurrent diseases of their intestinal tract and pancreas,” says Dr. Webster. “It’s called triaditis, and means all three are inflamed at once.”
Senior Symptoms
Signs of liver problems are similar and quite vague, whatever the type of disease.
Jaundice—yellowish tinge to the gums, whites of eyes, or inside of ears
Refusal to eat
Vomiting
Weight loss
Increased drinking and urination
Lethargy
Neurological signs including confusion or dullness
Diagnosis
Signs of liver disease are so vague it requires sophisticated tests to diagnose. “The owners sometimes notice they turn yellow,” says Dr. Webster, but that happens most often with advanced cases. Bile produced by the liver aids in the digestion of fat, and it can turn the cat’s skin yellow when it backs up in the blood circulation.
Also, increased pressure on the veins entering the liver can prompt an accumulation of fluid (ascites) causing the abdomen to swell, but that’s a rare finding in cats and much more common dog. Another rare consequence of liver disease is hepatic encephalopathy that affects the brain. “Toxins build up in the blood that the liver normally removes. It can go to the brain and cause confusion—they just look out of it,” says Dr. Webster. “Occasionally they can have seizures.”
A biochemical profile of the blood is the first step toward diagnosis. Liver enzymes may be elevated for a number of reasons, though, and elevated enzyme values does not automatically mean the cat has liver disease. “Probably the number one reason for a high liver enzyme in an old cat is thyroid disease,” says Dr. Webster. “You have to go further into diagnostic