LIVER DISEASE IN DOGS AND CATS

Helpful Buckeye has received several e-mails asking about liver disease in dogs and cats.  These pet owners report having been told by their veterinarian that their pet might have some type of liver disorder.  Apparently being of an inquisitive nature, some of these pet owners wanted to know a bit more about the liver and its diseases. 

Helpful Buckeye will offer you an overview of the liver's location, anatomy, and basic functions...before getting into what you might (and I emphasize the word, "might") look for as evidence that the liver is involved in what your dog or cat is experiencing.  That will be followed by an interesting presentation of Questions and Answers about liver disease.

Liver Disease In Dogs And Cats

The liver is a large, dark red organ located in the front part of the abdomen, just behind the diaphragm. The diaphragm is the physical partition between the thoracic (chest) and abdominal cavities. Conditions relating to the liver are called “hepatic” conditions, much like those affecting the kidneys are called “renal” conditions. “Liver disease” is a very general term used to describe any type of liver disorder.There is no one cause of canine liver disease.

Conditions relating to the liver in dogs are called “hepatic” conditions, much like those affecting the kidneys are called “renal” conditions.

The liver executes some of the most complex and vital functions in a dog’s body. It metabolizes fats, carbohydrates and proteins and is involved in the production of essential blood clotting factors. It synthesizes a number of key enzymes and helps remove ammonia from the bloodstream. The liver also stores vitamins and minerals and aids in the digestion and detoxification of circulating wastes, drugs and poisons.


The clinical signs of liver disease (medically referred to as “hepatobiliary disease”) are extremely variable due to the liver’s extensive interaction with other organs and its unusual regenerative capacity. More than one-half (and maybe up to 70 or 80 percent) of functional liver tissue must be destroyed before liver failure can be diagnosed.


Symptoms of Liver Disease in Dogs


Some dogs show no clinical manifestations of liver damage, especially in the very early stages of disease. Once symptoms do develop, they usually are nonspecific. The severity of any given symptoms does not necessarily correlate with the severity or extent of liver damage, or with the animal’s prognosis. Because the liver is intimately involved in so many essential bodily functions, what appear to be symptoms of liver disease might actually be caused by an abnormality in another organ or organ system. With this in mind, the general signs and physical examination findings often associated with liver disease, irrespective of its cause, include one or more of the following:

• Loss of appetite (inappetence; anorexia)
• Weight loss
• Nausea
• Vomiting (often intermittent but usually chronic)
• Depression
• Lethargy
• Disinterest in normal activities (apathy)
• Diarrhea (less common than vomiting)
• Dehydration
• Increased thirst/water intake (polydipsia)
• Increased frequency of urination (pollakiuria)
• Increased volume of urine output (polyuria)
• Weakness
• Unkempt hair coat
• Abdominal enlargement or distention (bloated appearance)

The distended abdomen is usually caused by an enlarged liver or spleen (“organomegaly,” which means an enlarged organ, or more specifically “hepatomegaly” or “splenomegaly”). It also is commonly caused by a build up of fluid in the space between abdominal organs (“effusion” or “ascites”) or by poor abdominal muscle tone (“muscular hypotonia”).


Some more specific signs of liver disease include:

• Jaundice (yellow staining of the serum, skin and mucous membranes caused by build-up of the bile pigment, bilirubin, in circulation. Also referred to as “icterus,” jaundice can turn a dog’s urine a bright, yellowish-orange color (bilirubinuria). It also frequently causes a yellow appearance to the whites of the eyes and mucous membranes of the tongue and gums.)
• Abnormal fecal color and consistency (acholic feces – or changes in fecal color – are caused by an absence of bile pigments in the intestinal tract due to abnormal retention in the blood, which makes the dog’s stools pale and putty-colored. This normally indicates complete bile duct obstruction associated with liver disease.)
• Spontaneous bleeding disorders (animals with liver disease often have problems with coagulation, or clotting, of their blood, called “coagulopathies”. In dogs, the upper gastrointestinal tract – usually the stomach and duodenum, which is the first part of the small intestine - is most commonly affected by coagulation disorders associated with liver disease. This leads to gastrointestinal bleeding/hemorrhage, which owners may detect by seeing blood in their dogs’ stools. Affected dogs may also vomit blood and/or have visible blood in their urine.)
• Blood in the feces (hematochezia)
• Blood in the urine (hematuria)
• Blood in the vomitus (hematemesis)
• Neurological and behavioral changes

Neurological and behavioral changes in dogs with late-stage liver disease are common. They are caused by high levels of circulating toxins that normally are removed by a healthy liver, but not by a diseased one. When these toxins accumulate in the brain, the dog develops a condition called hepatic encephalopathy, (“hepatic” means emanating from or pertaining to the liver). This often leads to:

• Aggression
• Agitation
• Disorientation
• Restlessness
• Trembling (tremors)
• Circling
• Lack of coordination (ataxia)
• Staggering
• Aimless wandering
• Mental dullness
• Dementia
• Stupor
• Pacing
• Head-pressing
• Blindness
• Excessive salivation (drooling)
• Generalized seizures
• Collapse
• Coma

These signs develop in dogs (and cats) with liver disease, because the cerebral cortex of the brain is exposed to intestinal toxins that normally are removed by a healthy liver but escape hepatic detoxification in cases of liver disease. Most gastrointestinal toxins are derived from normal bacterial metabolism - or digestion - of proteins and their byproducts. Ammonia is one of the most common intestinal toxins contributing to the symptoms of hepatic encephalopathy, which can wax and wane over time. Hepatic encephalopathy tends to be a chronic condition which cannot be cured, but often can be controlled.


Dogs with advanced liver disease can develop a debilitating skin disorder referred to as hepatocutaneous syndrome. The reason for this condition is not well-understood, but its symptoms may appear before signs of internal liver disease are apparent and include:

• Sores/lesions on the footpads (thickened, crusted, ulcerated)
• Foot pain
• Reluctance to rise, walk, exercise or play
• Itchiness (pruritis) of the feet
• Redness between the toes (interdigital erythema)
• Sores/lesions on the ear flaps, external genitalia, oral cavity, eyes, elbows, lower abdomen or elsewhere

Dogs at Increased Risk of Liver Disease


Most forms of liver disease are more common in middle-aged to older animals. However, congenital disorders, such as portosystemic shunts and congenital vascular disease, are more frequently seen in young dogs. Acquired copper storage disorders are more common in Bedlington Terriers, West Highland White Terriers, Skye Terriers, Keeshonds, Labrador Retrievers and Dalmatians. Breeds predisposed to chronic hepatitis include the Doberman Pinscher (mainly seen in females), Cocker Spaniel (males are overrepresented), Labrador Retriever, Standard Poodle and Scottish Terrier. Exposure to hepatotoxins is more frequent in free roaming dogs with access to chemicals, heavy metals, stagnant standing water, pesticides, poisonous plants or drugs. Free roaming dogs are also more likely to suffer acute blunt trauma to their liver. Healthy dogs exposed to dogs that have leptospirosis, canine infectious hepatitis or canine adenovirus infection have a greater risk of developing those diseases, which contribute to liver damage.


Only a skilled veterinary professional can assess a dog and perform the tests needed to confirm a diagnosis of liver disease.

Adapted from: http://www.petwave.com/Dogs/Dog-Health-Center/Digestive-Disorders/Liver-Disease.aspx  

Understanding Liver Disease in Pets

Dr. Dana Brooks, an veterinary internal medicine specialist at Seattle Veterinary Specialists in Kirkland, WA presents these Questions and Answers....

Question: What role does the liver play in a dog or cat’s body?
Answer: The liver has many functions. The main functions are detoxification (takes drugs or toxins out) of the blood stream, regulation of blood-sugar levels, maintenance of blood protein and cholesterol levels, production of bile that helps to metabolize fats and production and maintenance of normal blood-clotting factors.

Question: What can go wrong with a liver?
Answer: The basic disease processes are divided into infection; inflammation; toxicity; cancer; metabolic disease; congenital diseases; and trauma.

Most people think hepatitis (inflammation of the liver) is a viral disease, because this is common in people. But viral hepatitis is very uncommon in dogs. Cats, however, can develop hepatitis as part of the viral disease feline infectious peritonitis.

Infectious causes of hepatitis in dogs and cats are more commonly caused by bacteria, and less commonly by fungal, parasitic or protozoal diseases, such as fungal (blastomycosis), parasitic (roundworm migration in puppies and kittens), protozoal (toxoplasmosis).

Hepatitis can also occur when the body’s immune system attacks itself. This is one of the more common causes of liver problems in dogs and cats.

The cause of the immune-system disturbance is not always apparent. In cats, it is often associated with inflammatory bowel disease (usually associated with food allergies).



Some breeds of dogs can be predisposed to developing hepatitis, such as the Doberman, Labrador and cocker spaniel.


Chronic hepatitis can lead to cirrhosis, which is an irreversible condition in which healthy liver tissue has been replaced by nonfunctioning scar tissue.



Liver toxicities can occur from ingesting certain poisonous mushrooms (Amanita); blue green algae; xylitol (found in sugar-free items such as chewing gum); acetaminophen (Tylenol); and abnormal reactions to some therapeutic medications (arthritis medications, immunosuppressant medications, anticonvulsants, and some antibiotics).

Many different types of tumors can affect the liver, some benign, some malignant. The cancer can start in the liver or it can spread to the liver from another site (metastasis).


Some metabolic diseases like diabetes mellitus, hyperthyroidism and hyperadrenocorticism (Cushing’s) can cause elevations of liver enzymes.


The most common congenital disease to affect the liver is a portosystemic shunt. This occurs when an abnormally-located blood vessel allows blood to bypass the liver, which is responsible for removing toxins. There are also some rare storage diseases that can affect the liver in certain breeds (Bedlington terriers, West Highland white terriers, Doberman pinschers.)

Question: When the vet orders a complete blood chemistry to determine the health of my pet, what kinds of liver-related issues might he/she be looking for?
Answer: The main tests that give us information about liver health are ALT, ALP, GGT, AST and bilirubin. Increases in these numbers indicate that something is wrong with the liver, but not the specific disease process.


An ultrasound, aspirate or, preferably, a biopsy is usually needed to reach a definitive diagnosis. Other values such as BUN, albumin and cholesterol can be helpful as well. Decreases in these numbers indicate decreased liver function.


Another test that might be recommended when liver disease is found is bile acids, which looks at liver function more specifically. These are very elevated with shunts and liver failure.


Question: What are the physical symptoms of liver problems?
Answer: Some dogs and cats will have no symptoms of liver disease, and it is discovered on routine blood work. Symptoms in ill dogs and cats can include vomiting, decreased appetite, weight loss, seizures or disorientation (with shunts or end-stage liver failure), or a yellowish discoloration of the skin (jaundice or icterus).


Question: Is liver disease treatable or reversible? How quickly can liver cells rejuvenate?
Answer: Infectious hepatitis can be treated with antibiotics and should be reversible with the exception of viral disease. Immune-mediated hepatitis isn’t cured, but it is managed with medications that suppress the immune system.

Metabolic disease is treated by treating the specific underlying disease process.


Toxicities are usually treated with supportive care and the damage is often reversible.


Cancer of the liver may be treated with surgery or chemotherapy based on the type.

Liver shunts are treated with surgery to close the abnormal blood vessel.

The exact amount of time for liver regeneration is not known and depends on many factors, such as how much damage occurred and how healthy the remaining liver tissue is. In general, weeks to months is most likely.


Question: Are any liver problems age-related?
Answer: Liver tumors tend to be more common in older dogs and cats, although liver cancer could potentially occur at any age.


Young animals tend to be more prone to toxicities because they tend chew inappropriate things, and shunts are usually found in puppies or kittens if they are severe enough to cause clinical signs.


Question: Are there foods or diets that can improve the health of my pet’s liver? Are there some we should definitely avoid?
Answer: Dogs and cats with significant liver dysfunction usually do better on a lower protein diet. The liver is responsible for detoxifying some of the bacterial byproducts of protein digestion, and by supplying a higher quality but lesser amount of protein, the liver is delivered less of a load of substances to remove.

There are some prescription diets designed for dogs with liver disease that are limited in copper (copper tends to get deposited in the liver cells when there is chronic inflammation and it can continue the damage), and supplemented in zinc (helps to decrease copper absorption and removal of copper from the liver), and vitamin E (for it’s antioxidant effects).


Other than avoiding high protein in dogs and cats with liver disease, there are no other specific foods to stay away from. A high-fat diet is usually not a problem with primary liver disease.


Question: If my dog is a breed that is prone to liver problems, or I know problems have cropped up in the breeder’s line of dogs, should I have tests done more frequently or be on the lookout for certain symptoms that may appear? How can I be proactive?
Answer: Hepatitis is often asymptomatic (there are no symptoms that you can see), but yearly chemistry profiles are sufficient for most dogs and cats. Anytime a dog or cat becomes lethargic, is vomiting or has a decreased appetite, blood work is usually a good idea.


Question: Are liver transplants available for pets? Can partial livers be used in transplant as they can in humans?
Answer: To date liver transplants have not been routinely successful in dogs or cats. Much of the difficulty arising from liver transplantation is ethical (taking organs from a healthy dog not able to deny consent), and the availability of a compatible donor.

Adapted from: http://seattletimes.nwsource.com/html/tailsofseattle/2017382764_veterinary_qa_liver_disease.html

As you can easily tell from these presentations, the signs and symptoms of liver disease in your pets are very general in description and, for the most part, don't necessarily point right at the liver as being involved.  That's where the detective diagnostic efforts of your veterinarian come into play.  Getting your dog or cat to your veterinarian as soon as you realize something's just not right and then describing what you are seeing will give your pet the best chance of surviving a liver disease.

Any questions or comments should be sent to Helpful Buckeye at: [email protected]  or submitted through the "Comments" section at the end of this issue of Questions On Dogs and Cats.

SPORTS NEWS

The LA DODGERS have put themselves on a roller coaster again this past 7-10 days.  After sweeping a 3-game series from the hated Giants, we went home to LA and promptly lost a 3-game series to the Diamondbacks, then swept a 3-game series against the Cubs.  This allowed the D'Backs to make the NL West division into a 3-team pennant race...August and September could be very interesting since all 3 teams play each other 9 more times.

PERSONAL STUFF
Desperado and Helpful Buckeye have been invited to a summer evening "tasting menu" at our favorite Arizona restaurant marking the arrival of a new executive chef...and we plan to do so this week.  We'll also be using this as a sort of celebration of Desperado's recent good news.  Following this dinner, we'll start hitting the trail again...catching up on some day trips and 2-3 day trips that we've had planned.

Helpful Buckeye has been gradually making the partial transition from this activity...

to this activity...in preparation for my next challenging experience.

Guess what showed up this past week...some things never ever lose their luster!

~~The goal of this blog is to provide general information and advice to help you be a better pet owner and to have a more rewarding relationship with your pet. This blog does not intend to replace the professional one-on-one care your pet receives from a practicing veterinarian. When in doubt about your pet's health, always visit a veterinarian.~~