Back in my veterinary clinical practice days, I vividly remember a cat whose owner brought him in because he had lost his appetite and just wasn’t “acting right.” I remember this cat so clearly because Warlock was magnificent: big and beautiful, with long, black fur and dazzling green-gold eyes. But what was even more striking about Warlock was the alarming color of his skin and gums – a glowing, neon-yellow color so obvious I’m pretty sure it could have been seen from space.
As veterinary professionals, very rarely were we able to simply look at a dog or cat and make an instant diagnosis, but in this case the problem was staring us right in the face. Poor Warlock was having a major problem with his liver, and it needed to be addressed, pronto!
Liver disease in dogs and cats can be caused by a wide variety of disorders that ultimately result in any type of damage to the liver. It’s estimated that 3% of all disease cases seen by veterinarians are liver-based. Once we understand exactly how critical the liver is to the body’s survival, it’s easy to see why this is the case.
Meet The Liver: The Body’s Workhorse
The liver is the largest organ in the body. As the body’s main “industrial center”, it’s responsible for so many important functions that 25% of the blood pumped out with every beat of the heart goes straight to the liver. Some of the liver’s major functions include:
- Producing bile needed for digestion
- Regulating metabolism
- Synthesizing hormones and proteins
- Filtering toxins (including drugs, chemicals, and the body’s own byproducts) from the bloodstream
- Storing vitamins, minerals, and glycogen (a fuel source)
- Removal of old, damaged red blood cells
- Storing extra blood and iron
- Producing proteins needed for blood clotting
- Acting as an essential part of the immune system by breaking down and eliminating bacteria, toxins, and chemicals brought into the liver via the portal vein
Since the liver is involved in almost every biochemical process needed to run the body, liver disease can affect just about any other part of the body. When the liver isn’t working properly, digestion is affected, there can be a shortage of essential vitamins and nutrients, and dangerous toxins can build up in the bloodstream and tissues.
Unlike most other organs, such as the heart, kidneys, and brain, the liver has an amazing ability to repair itself once it’s been damaged. This ability to regenerate is what makes it possible for a diseased liver to actually completely return to normal function (if the damage is not too severe), resulting in a full recovery.
Another amazing thing about the liver is that it has a tremendous reserve capacity – it can easily perform its duties with up to 80% of itself affected by disease or cancer. Although this is beneficial in keeping a dog or cat with liver disease alive for a long period of time, the downside is that the extent of damage to the diseased liver may not be found until the liver has reached the point of no return.
What Causes Liver Disease In Dogs And Cats?
Liver disease, also referred to as hepatitis, is a broad term that describes a number of different liver conditions that can be brought about by several different causes. These can include:
Trauma to the liver can result from a severe blow to the front of the abdomen (most commonly from being hit by a car); severe bruising sustained during a fight, physical abuse, or a fall; heat stroke; diaphragmatic hernia; or liver torsion (where the liver becomes twisted).
Caused by bacteria, viruses, or fungus.
Certain drugs (including some antibiotics, steroids, anti-inflammatories, diuretics, dewormers, seizure medications, and antifungals), chemicals (lead, arsenic, and those found in pesticides and lawn treatments), toxic plants (poisonous mushrooms, blue-green algae, and ragwort), and mycotoxins (such as the toxic mold that grows on corn) have all been linked to liver disease in dogs and cats. Keep in mind that most liver damage caused by medication results from overuse of the drug.
Many cancers that develop elsewhere in the body travel through the bloodstream to the liver, causing secondary tumors that lead to liver disease.
Liver disease can also be genetic. Dog breeds predisposed to developing liver disease include the Doberman Pinscher, West Highland White Terrier, Cocker Spaniel, Skye Terrier, and Bedlington Terrier. Cat breeds include the Siamese, Abyssinian, Burmese, and Somali. However, any breed of cat or dog can develop liver disease.
A condition called Autoimmune Hemolytic Anemia can decrease the oxygen available to liver cells, causing them to die off.
Heartworms can block blood flow from the heart to the liver and cause the liver to fail.
Hepatic Lipidosis (Fatty Liver Disease)
This is a condition that can occur in cats whenever they stop eating, or if their food intake is drastically reduced.
Sometimes the liver becomes inflamed for no apparent reason. This is referred to as an “idiopathic” condition, which means it has no known cause.
Other metabolic diseases can cause secondary liver problems as well. These include:
- Hypothyroidism (low thyroid hormone levels)
- Cushing’s Disease
- Hyperthyroidism (high thyroid hormone levels)
Symptoms Of Liver Disease In Dogs And Cats
Unfortunately, symptoms of liver disease vary greatly, from extremely mild to quite severe. They can also mimic many other types of illnesses.
As with Warlock the cat, the most outwardly-telling sign of a liver in trouble is yellow gums, skin (especially inside the ears and on the paw pads), and whites of the eyes. This is called “icterus”, also commonly known as jaundice, and it’s the result of a buildup of bilirubin (a yellow bile pigment) that occurs when the liver is not functioning normally. The urine of a dog or cat with liver disease can also be a bright, orange-yellow color. If you notice either of these symptoms in your dog or cat, get them to a veterinarian immediately.
Other symptoms of liver disease in dogs and cats can include:
- Weight loss
- Poor appetite
- Excessive thirst
- Excessive urination
- Unusual bruising anywhere on the body
- Abdominal pain
- Distended or swollen abdomen (due to a buildup of fluid, or an enlarged liver)
- Pale gray-colored stool
- Lethargy, depression
- Head pressing or head tilt
- Pacing or walking in circles
- Any behavioral changes, particularly right after a meal
Diagnosing Liver Disease
If you suspect your dog or cat might have a liver problem, have them examined by your veterinarian immediately. Several different tests can be run to confirm if liver problems are present, including bloodwork (CBC/Chemistry panel, bile acids test, clotting profile, and ammonia levels), x-rays or ultrasound (to look for liver swelling or tumors in the liver), and a urinalysis (to check for the presence of bilirubin in the urine).
In some cases, a liver biopsy can also be taken and a trained pathologist can examine the liver cells under a microscope to determine if disease is present and exactly what the cause is. However, this procedure involves general anesthesia, and might not be necessary if liver disease can be confirmed with bloodwork, ultrasound, or other testing.
Treatment Of Liver Disease
Treatment of liver disease in dogs and cats can vary based on the actual cause of the disease and how severe it is.
The basic goals for treating liver disease are 1) to remove exposure to any toxic agents (such as any drugs or chemicals in the dog’s or cat’s environment that could be causing a problem), and 2) to support and protect the liver while it heals. This usually involves a short hospitalization, with the patient on intravenous (IV) fluids, antibiotics, and cage rest. Additional medications can be given to help with nausea and vomiting, as well as vitamin and mineral supplements to ensure the body is getting what it needs.
Patients are also fed a diet high in quality protein (which keeps the body’s ammonia levels from going too high) and low in sodium (to prevent water retention). If the body is retaining too much water, diuretics may be given to help eliminate excess fluid.
Cats with hepatic lipidosis will need to be force-fed or have a feeding tube placed to ensure that they’re getting enough calories for the liver to function the way it’s supposed to. In severe cases where the liver is failing, a blood transfusion may be necessary.
Liver disease must be treated correctly, not only to prevent further damage to the liver, but also to prevent a serious brain condition called hepatic encephalopathy. This condition, caused by a buildup of dangerous levels of ammonia due to the liver’s inability to process it, can result in blindness, deafness, or coma if not treated promptly.
Protecting Against Liver Disease
Treatment for liver disease in dogs and cats has dramatically improved over the last several years due to more sophisticated diagnostic testing and a better understanding of all the different conditions that can affect the liver.
Although liver disease may not be completely preventable, there are some things you can do to help lower your dog’s or cat’s chances of developing it. First, keep your pets healthy by feeding them a high-quality diet. Diets high in fat can lead to pancreatitis and liver problems. Second, make sure your pets have a health exam at least once a year, and that your veterinarian is aware of all drugs or supplements that your pets are taking.
Don’t let your dog or cat roam free in areas where there may be poisonous plants or areas treated with pesticides or weed killers. And if you have an overweight cat, don’t put him on a diet or suddenly restrict his caloric intake without first speaking with your veterinarian, as this can cause an onset of hepatic lipidosis. Most importantly, stay alert and monitor your dog or cat for signs of liver problems.
As for Warlock, the cat with liver disease? Well, I’m happy to say that after 3 days of hospitalization, treatment with IV fluids and antibiotics, and good supportive care, he made a complete recovery and never had another recurrence. The liver truly is an amazingly resilient organ!
Have you ever had a dog or cat with liver disease? Please tell us about it in the comments below!