Liver Disease in Dogs: Part I
The liver is an amazingly complex organ and is responsible for multiple functions in the body, all of which are vital for good health. Such multi-tasking means that there are a number of things that can go awry. It’s not surprising then that canine liver disease is so common.
The liver happens to be remarkably resilient and, to a great extent, can regenerate and restore itself following damage. Additionally, because the liver contains multiple lobes, significant disease in only one or two of them doesn’t typically impair liver function.
Liver function
Before blood from the abdominal organs travels back to the heart, it must first pass through the liver via a large vessel called the portal vein. Once within the liver, hepatocytes (liver cells) detoxify the blood, removing any undesirable substances such as toxins or bacteria. This detoxification process is the reason a dog can recover from “food poisoning” after dining on a rotten carcass.
In addition to its role as the “garbage disposal” of the body, the liver also acts as a manufacturing plant, producing substances such as proteins, fatty acids, glucose, cholesterol, and blood clotting factors. These essential products are released from the liver into the bloodstream for use throughout the body.
The liver serves as a storage unit for several essential nutrients, vitamins, minerals and glycogen, an important source of energy release during exercise. The liver also produces bile (bilirubin) and stores it within the gallbladder so it is ready for release into the small intestine when needed for fat digestion.
Symptoms of liver disease
There is no classic combination of symptoms that alerts one to the diagnosis of liver disease. Rather, many liver-related symptoms overlap with those of other illnesses. Symptoms can range from single to multiple, and from mild to severe. Believe it or not, some dogs with significant liver disease demonstrate no overt abnormalities whatsoever (one of the many reasons routine canine senior citizen blood screening is a really good idea).
The more common liver disease-associated symptoms include:
- loss of appetite
- lethargy
- vomiting
- diarrhea
- increased thirst
- jaundice
- abdominal distention caused by fluid accumulation
- neurological abnormalities (hepatic encephalopathy)
Diagnosis
There are typically two stages of testing involved in diagnosing liver disease. While the first stage confirms that a liver abnormality is present, this testing doesn’t hone in on the clear-cut cause of the problem. All it says is that some type of liver disease is. The second stage of testing is used to confirm the exact type of liver disease present. A liver biopsy is often needed to make this distinction although, on occasion, the ultrasound alone is confirmatory. A liver biopsy is an invasive procedure. It’s potential risks and benefits must be carefully evaluated before proceeding, particularly with dogs whose health is significantly compromised.
First stage testing
- thorough physical exam
- complete blood cell count (CBC)
- chemistry profile
- urinalysis
- bile acids test
- blood clotting studies
- abdominal x-ray
Second stage testing
- abdominal ultrasound
- liver biopsy collected via surgery, laparoscopy, or with ultrasound guidance
How liver function is assessed
Several different blood tests are utilized when diagnosing liver disease. The chemistry profile measures ALT (alanine aminotransferase) and AST (aspartate aminotransferase), enzymes contained within the liver cells. Elevations of these two enzymes indicate that at least some of the liver cells are “unhappy,” enough so that they are leaking excess ALT and AST into the bloodstream. This is really the only information provided by these two enzymes. They don’t reveal anything about how the liver is functioning. In other words, one could not diagnose liver failure on the basis of ALT and AST results. Unfortunately, measurements of these two enzymes are often referred to as “liver function tests,’ a term that I believe to be very misleading. (Okay, I’ll jump off of my soapbox.)
So, how then does one evaluate liver function? The chemistry profile also measures albumin, glucose, urea, and cholesterol all of which are manufactured within the liver. Decreased amounts of these four substances in the bloodstream are indicators that liver function is impaired.
Blood clotting factors are also made within the liver, and abnormally prolonged blood clotting times are consistent with liver dysfunction. A bile acids test is yet one more way of screening for impaired liver function.
Stay tuned for Liver Disease: Part II to learn about the causes and treatment of liver disease.
Have you cared for a dog with liver disease? If so, how did things turn out?
Best wishes,
Nancy Kay, DVM
Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
Become a Fan of Speaking for Spot on Facebook
Please visit http://www.speakingforspot.com to read excerpts from Speaking for Spot and Your Dog’s Best Health. There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at http://www.speakingforspot.com
Hi Sharon. It sounds like you are doing a great job managing your dog’s liver disease. Has abdominal ultrasound been performed?
Learned 18 months ago my 55-pound 12-year-old mixed breed (mostly collie, English setter and cocker spaniel, according to DNA), who’s a retired certified therapy dog, had very elevated liver values. 784 ALP, 170 ALT and 76 AST. My vet immediately prescribed milk thistle, vitamin E and SAM-E (She doesn’t love Denamarin because she likes to be able to adjust for size a bit more precisely than Denamarin allows). Dr. Tweedt at Colorado State University, who apparently literally wrote the book on liver disease that vet students use, recommended Ursodiol be added to that regimen. Ultrasound showed nothing abnormal. Within two months, ALT and AST were back to excellent levels. ALP has remained high, hovering in the high 300s to the low 400s. Jasper continues to take the meds he started last year. I also feed him relatively low protein food (18 percent protein Blue Buffalo dry, and wet food that is typically 8 to 10 percent protein–mostly whatever good quality is on sale at Petco). He seems to feel very good. We walk at least four or five miles a day, and although he’s slower than he once was, he’s now 13 years old, so I want to think maybe it’s age that’s causing that, not that he’s feeling kind of crummy. Also, I get bloodwork every three months just be be certain nothing’s spiking. Still, I worry because the ALP numbers are never good. My vet always says “we’re treating the dog, not the numbers, and he’s doing great.” And he is. It must be noted it ain’t cheap. Usodiol is $105 a month (and that’s the Costco price) although I get it at the CSU compounding pharmacy for $50 a month, which is a huge help, of course.The herbals run about $40 total a month. And I feed dry with the wet food even though the protein count is only about half as much in wet as dry because feeding 100 percent good-quality canned food to a dog his size would be about $12 a day. Doing the combo and hoping I’m not overloading him with protein seems to be working fine. I’m also feeding him three times a day recently in an effort to not press his system too much at one time. CSU recommended a biopsy so we’d have real answers, but my vet and I decided to pass on that–there are the usual risks, plus Jasper is allergic to sutures, so that seems a bad move for this dog. Eager to learn of any other strategies people are using that might help keep him feeling good.
One of my 10 year old Labs developed copper toxicosis. It has been an adventure in learning about liver maintenance. She is taking Denamarin, PhosChol, Vitamin E, and Omega 3 Fatty Acids to improve liver function and d-penicilamine to remove the copper from her liver. She is on a special no copper diet with dietary supplements to balance her diet. She has survived 19 months and is doing well.
i have learned a lot about livers.
First, my deep condolences to Janet on the loss of your dear Border Collie. It’s so hard to let them go; I’ve been there more times that I care to remember.
A few years ago, one of my dogs, Gambit (Siberian Husky), was in liver failure. I later found an empty box of d-con rat poison in my yard; I suspect some monster threw it over our fence to cause harm. We rushed to my vet, and I will tell you now that Gambit is absolutely fine: no suspense! My vet sold me a “prescription diet” l/d (although the FDA recognizes NO medical value in any dog food). I got home, looked at the ingredients, and took it back. Almost all the ingredients were notoriously GMO (especially corn and soy), and tests show that GMO foods often cause liver and kidney failure in animals, so there was no way I was giving that garbage to my dog. I explained all that and sent links to the tests; my wonderful vet discontinued selling the junk. Instead, I did online research for diet treatments, and home-cooked the recommended diet for several weeks. He got silibinin supplements and if memory serves, some prescription meds as well. This was several years ago, so details have slipped my mind. Within a couple of months he made a full recovery, and he is happy and healthy and delightful. I saved the links for future reference, if anyone needs them.
Hi Helene. The product you are thinking of is called Denamarin and I will be talking about it in Liver Disease in Dogs: Part II! Hope all turns out well with your sweet Labrador.
Hi Wendy. I hope all turns out to be just fine on your Rhodie’s next check up.
My Sweet Lab had elevated liver levels along with other issues. Before doing extensive testing my vet immediately wanted her on Milk Thistle 300 miligrams once a day. There is also one for dogs I think called Dematarin. It appears that quite a few people I have spoken to also have their dogs on it as well.
My 15 month old female Rhodesian Ridgeback has elevated ALT. In January it was 296. In July it was 244. She is on conservative treatment taking two capsules twice a day of hepato- liver support. Blood to be retested 4 to 6 weeks from last test. All other labs were in the normal range. She exhibits no symptoms.
My old Border Collie was diagnosed with Copper Hepatopathy. We lost her just a couple months after diagnosis. She wasn’t eating and dropped more than a quarter her body weight. Despite the excellent care from Tufts and our regular vet, she just continued to decline until it wasn’t fair to ask her to hold on any more.