Mammary Gland Tumors

We recently had a cat come in with a mammary gland tumor, which made me think that it would be good to discuss mammary tumors in dogs and cats.  Let's start with dogs.

Diagram of mammary glands in dogs

Of any of the domesticated animals, dogs have the highest incidence of mammary tumors.  Females who are spayed before their second heat cycle have a significant decrease in the incidence of mammary tumors compared to dogs who are left intact or spayed after their second cycle.  One of the good news for dogs with mammary tumors is that around half of the tumors act in a benign fashion.  This means that they typically grow locally in the mammary gland alone and do not spread.  Unfortunately, this means that the other half of tumors are more aggressive and have spread by the time they are diagnosed.  The smaller the tumor (<3 cm) the more likely that the tumor will be benign.  If the local lymph node is involved or the tumor has spread elsewhere (lungs), then these tumors tend to be more aggressive.

What will happen if a mass is felt on your dog.  Typically, complete staging should be performed prior to treatment.  This can involve performing labwork, taking chest x-rays (to check for lung nodules), aspirating the local lymph nodes if enlarged (to look for cancer cells), and possibly performing an abdominal ultrasound (to check for any nodules in the liver, spleen, etc).  If the tumor shows evidence of spreading, then additional therapy beyond surgery, such as chemotherapy, may be recommended.

Typically, the mainstay of treatment for the primary mass is removal of the affected mammary gland (mastectomy).  If multiple mammary glands are involved or a lymph node is involved, then all affected glands and the nodes should be removed.  After removal, the masses should be submitted to a lab where histopathology will be performed and the origin of the mass can be identified.  Although there are no definitive studies showing an added benefit of chemotherapy with mammary tumors, many veterinarians will recommend a course of chemotherapy in dogs where the tumors are thought to be more aggressive (metastasis, large size, etc).  Some vets may also recommend spaying (if not already done) the dog at the time of mass removal as some tumors may be responsive to hormones released by the ovaries.

Mammary mass form a dog

For dogs with small tumors, surgical removal may be completely curative and monitoring of the other mammary glands is the only long term recommendation.  However, tumors that are larger and more aggressive typically carry a worse prognosis of only a few months to a year.  It is important to bring your pet in for an annual exam as your veterinarian may be able to pick of a mammary mass before it becomes too large.

Cats can also develop mammary gland tumors.  Like dogs, female cats who are spayed earlier in life have a significant decrease in the incidence of mammary tumors.  Unlike dogs, most feline mammary tumors (greater than 80%) tend to be malignant.  Tumors that are smaller (<3 cm) tend to carry a better prognosis (possibly as long as 2 years), whereas prognosis for larger tumors tends to be poor (4-6 months).

Similar to dogs, staging with labwork, imaging, and evaluation of the local lymph nodes should be performed. With cats, most veterinarians recommend removal of all the glands on the affected side versus just a simple mastectomy.

Feline Conjunctivitis

We commonly see cats come into the clinic with eye problems.  Most of the time it has to do with conjunctivitis (inflammation of the conjunctiva which is the lining under the eyelid and over a portion of the eye itself).  Especially in kittens, the swelling can be quite dramatic and in cases where it is not treated can lead to problems with vision.

Severe conjunctivitis

The first thing we try to determine is the cause of the inflammation.  Although there are a number of different causes, there are three causes that occur most frequently.  These are viral infections, bacterial infections, and allergies.  In many cases we may not get the exact diagnosis, but response to treatment gives us a good idea if we are on the right track.

An eye exam can help rule out things like eyelid conformation issues, foreign bodies, or trauma.  After this, staining of the eye may be performed which can show changes consistent with a viral infection (dendritic ulcers on the cornea) or other scratches.  Conjunctiva swabs may also be taken which in some cases can show evidence of bacterial infection when looked at under a microscope.  With recurrent or non-responsive cases further testing with blood tests to evaluate for certain infections may be performed.

The most common viral infection causing conjunctivitis is a herpes virus infection.  In addition to eye problems, other upper respiratory signs like sneezing or congestion may also be seen.  This virus is the same type of virus that causes cold sores in people and can stay dormant in the body for long periods of time.  During times of stress the virus can reactivate and cause clinical signs.  In mild cases, the signs typically resolve on their own in 7-14 days.  In more severe cases, anti-viral therapy may be needed.  This can vary from using lysine, which is an amino acid that interfers in the replication of the virus to more specific anti-virals that can be given either orally (famciclovir) or topically (idoxuridine).

Applying drops to a cat's eye

The most common bacterial infections are Chlamydia or Mycoplasma.  Again, in mild causes these may improve on there own over a few weeks.  In more severe causes antibiotics may be needed.  Both bacteria typically respond to a tetracycline based antibiotic.  These can be given orally or topically as well.  We can have problems with esophagitis with tetracycline drugs, so many veterinarians substitute with azithromycin.

If an infectious problem is not suspected and an allergy is more likely (seasonality to signs, irritants like smoke in the air), then topical anti-inflammatories are usually helpful (steroids).

Please let me know if you have any questions.

Always Being Surprised

One of the nice things about being a veterinarian is that you constantly are learning and seeing new things.  Just recently, I saw a new client whose dog was having a problem after urinating.  The owner reported that after her male dog urinated he would continue to dribble urine and get it on himself.  He was four years old and the problem had probably been going on for a couple of years.  The previous veterinarian prior to the owner moving to our area had run a few diagnostic tests on the urine, but did not find anything conclusive.

After hearing the history I started out with a physical exam and pretty soon felt like I had found the possible culprit.  Male dogs have a skin fold called the prepuce (similar to foreskin in humans) that covers and protects the penis.  In this case, the opening of the prepuce was very narrow and there was a large amount of extra skin.  I thought that the narrow opening was leading to the urine pooling in the extra skin and then dribbling out after the dog was done urinating.  I suggested that we perform surgery to remove the extra skin and make the opening wider.

The owners agreed and we performed the surgery the next week.  I called for an update a couple days later and the owners reported that the problem was resolved and no more dribbling was happening.  If you would have told me in vet school that I would essentially circumcise a dog I would have laughed, but like I said earlier, I am always surprised at what I get to see and do as a veterinarian.

Cold Weather Precautions

It was -11 degrees this morning when heading to work, so I thought it would be prudent to discuss cold weather considerations for pets.  Most of the recommendations are fairly straight forward, but I thought I would review them anyway:

1.) Make sure your pet has adequate shelter.  If your pet isn't going to be indoors with you, then make sure they have an place to stay warm.  This should mean an insulated and draft free shelter.  In cases where the temperature is dangerously low (such as today) I would strongly suggest allowing your pet inside where there is heat.

2.) Have adequate water and food available.  Also, make sure that the water isn't frozen.  When temperatures are cold pets have a higher metabolic rate, so will need more calories.  Make sure that enough food is available to them.

3.) Protect pets feet.  Many people will put out salt to help with the ice on driveways.  This can be irritating to pet's paws, so make sure to wipe down pets feet after being outside.  Also make sure that pets are not running over sharp areas of ice or snow that could cut their paws.  Booties are available for dogs and many dogs are surprisingly tolerant of them.

4.) Watch for ice.  Dogs tend to have a better footing than people, but they can still take a tumble on the ice.  Especially with older pets, make sure that the walking routes you are taking are clear and ice-free.

5.) Lastly, make sure that any antifreeze is stored up and out of the way of pets.  A very small amount of antifreeze ingested by pets can put them into kidney failure.  For those do-it-yourselfers, make sure to keep this liquid away from your pets.

Hope everyone stays warm and safe during the current cold streak.  Happy New Year!!!

Some Fun Quotes

With the holidays, I thought I would do a little lighter topic.  Here are some fun pet related quotes:

“Don’t accept your dog’s admiration as conclusive evidence that you are wonderful.”-Ann Landers

“Did you ever walk into a room and forget why you walked in? I think that’s how dogs spend their lives.”

-Sue Murphy

"Dogs are not our whole life, but they make our lives whole." -Roger Caras

"A cat is a puzzle for which there is no solution." -Hazel Nicholson

"Animals are such agreeable friends - they ask no questions, they pass no criticisms." -George Elliot

“Dogs are the leaders of the planet. If you see two life forms, one of them's making a poop, the other one's carrying it for him, who would you assume is in charge.” -Jerry Seinfeld

"I like pigs. Dogs look up to us. Cats look down on us. Pigs treat us as equals." -Sir Winston Churchill

Hope everyone has a happy holiday.

Silly dog, You ate what???

Now that I have discussed hazards among cats, lets talk about problems that dogs may encounter.

1.) Tinsel, ribbons, and ornaments:  Although these decorations are not toxic, they can definitely cause problems with your pets.  In particular, longer, thin decorations can cause major problems as they tend to turn into linear foreign bodies.  Unlike a ball, corn cob, etc that may be eaten and removed fairly easily, longer string like objects tend to get hooked higher up in the stomach and intestine and then continue to move down the intestinal tract.  This leads to a large amount of damage that tends to make it more difficult to remove and heal from.

2.) Holiday lights and candles: The constant flickering of lights or bright colors can be very attractive to pets.  The problem with this is the electricity running through the lights.  You may not get the reaction like in "National Lampoon's Christmas Vacation," but biting into a cord can cause significant mouth burns and possibly death.  Make sure lights are out of the way of your pet.

3.) Holiday food: With the holidays comes baking and cooking, so be cognizant of what you leave out.  Chocolate is a big concern in dogs.  Although all chocolate is bad, baking chocolate contains the most methylxanthines, which can cause heart arrhythmia and death in large enough doses.  Other fatty foods and trimmings can also cause issues.  High fat foods can trigger pancreatitis in your pet leading to vomiting, pain, dehydration, and in severe cases, death.

4.) Antifreeze: Although not really a holiday problem, antifreeze becomes more readily available during colder months.  In the past antifreeze has been enticing to pets due to its sweet taste.  Fortunately, legislation passed last year that requires manufacturers of antifreeze to add a bittering agent to the liquid that will make it less tempting to pets.  Pets only need to be exposed to a small amount of the liquid to cause a problem.  Pets typically succumb to renal failure if they are not treating early and aggressively.

5.) Holiday plants: The good news is that most plants will only produce mild gastrointestinal upset if your pet is exposed to them.  Poinsettias, holly, and mistletoe typically fall under this category, but with large exposures there can be other problems, so always contact your veterinarian.

The best way to avoid a problem with your pet this holiday season is to keep anything that could be a hazard out of their reach.  Have a safe and happy holiday season.

Holiday Hazards

With the holidays quickly approaching I wanted to take time to discuss some holiday hazards to try to avoid.  The first post will deal mostly with cats and is taken from Dr. Tina Wismer's handout from a talk she gave for a rounds discussion in 2010.  Listed below are some common items that a cat might encounter during the holidays along with descriptions of possible problems.

1.) Silica Gel Packs

Desiccant packs are included as moisture absorbents. They are found in shoeboxes, electronics, medications and food. Silica gel comes in paper packets or plastic cylinders. Packages of silica gel are attractive to pets because of the rustling noise, and the packages are easy to bat around. Most ingestions will not cause clinical signs, although a mild gastrointestinal upset may occur. If a large amount is ingested, there is potential for diarrhea occurring. In most cases, the packet will be ruptured and the contents eaten. Ingestion of the intact packet may cause an intestinal obstruction.

2.) Christmas tree preservative

Christmas tree preservatives primarily contain dextrose and NPK fertilizers. The concentration of metals (copper, iron, zinc, magnesium) is usually small in commercial products. Most cats that drink water containing Christmas tree preservative develop no signs. Occasionally we can see mild GI signs, rarely, bacterial/fungal contamination of the water may lead to more severe signs.

3.) Christmas trees

Christmas trees may be one of several species. The most common are: Douglas fir (Pseudotsuga menziesii), Balsam fir (Abies balsamea), Black spruce (Picea mariana), Blue spruce (Picea pungens), White spruce (Picea glauca), Scotch pine (Pinus sylvestris), Norway spruce (Picea excelsa), Red Pine (Pinus resinosa), and Red spruce (Picea rubens). The most common clinical signs after ingestion of the needles are vomiting, anorexia, abdominal pain and depression.

4.) Poinsettias

The toxicity of poinsettias is generally overrated. The plants do contain diterpene esters, but large quantities must be ingested for signs to develop. Most cats just experience mild, self-limiting vomiting that resolves with little to no treatment.

5.) Mistletoe

Most ingestions involve American mistletoe (Phoradendron spp.). Mistletoe contains lectins, but ingestion of a few leaves or berries will generally cause just a mild gastritis. If purchased in a store, the berries frequently have been removed and replaced with plastic "berries" which can be a foreign body. Large ingestions may require decontamination and cardiovascular monitoring.

6.) American Holly

American holly (Ilex opaca)is a member of the Aquifoliaceae family. All parts of the holly plant are considered to contain potentially toxic compounds, including methylxanthines, saponins, and ilicin. True toxicoses not generally expected in cats. Most ingestions cause gastrointestinal irritation and depression. Recent ingestions can usually be managed with dilution and monitoring at home.

7.) Lily

Members of the Lilium and Hemerocallis genera (Easter lilies, tiger lilies, day lilies, etc.) cause acute kidney failure in cats. The water soluble toxic principle is unknown. Even minor exposures (bite on a leaf, ingestion of pollen) may result in toxicosis, so all feline exposures to lilies should be considered potentially life-threatening. It should be noted that not all plants with “lily” in the name are members of Liliaceae.

Affected cats often vomit within a few hours after exposure. Within 24 to 72 hours of ingestion, kidney failure develops, accompanied by vomiting, depression, anorexia, and dehydration. Elevations in BUN, creatinine, phosphorus and potassium are detectable as early as 12 hours post ingestion. Creatinine elevations may be especially high.

In severe cases, death or euthanasia due to acute renal failure generally occurs within 3 to 6 days of ingestion. When initiated within 18 hours of ingestion, decontamination (emesis, oral activated charcoal, and cathartic) and fluid diuresis for 48 hours have been effective in preventing lily-induced acute renal failure. Conversely, delaying treatment beyond 18 hours frequently results in death or euthanasia. Baseline renal values should be obtained upon presentation and then repeated at 24 and 48 hours. Because the tubular injury from lily ingestion spares the renal tubular basement membrane, regeneration of damaged tubules may be possible. In severe cases, peritoneal dialysis may aid in managing renal failure until tubular regeneration occurs (10-14 days or longer).

8.) Ice Melts

Many brands of sidewalk ice melts are on the market. The most common ingredients in these ice melts are sodium chloride, potassium chloride, magnesium chloride, calcium carbonate, and calcium magnesium acetate. A few ice melts contain urea. Cats may be exposed by walking on the ice melts themselves or by ingesting granules brought inside on the shoes of the owner’s.

Ingestion of urea is not a toxicity issue in non-ruminants. Ingestion of sodium, potassium, calcium and magnesium salts can lead to vomiting and electrolyte abnormalities. Monitor electrolyte levels and treat with appropriate fluid therapy.

9.) Liquid Potpourri

Liquid potpourri is commonly used during the holiday season. Cats are often exposed to liquid potpourri by direct ingestion from simmer pots or spills, or by rubbing against leaky bottles or simmer pots containing the potpourri, or from spilling the containers upon themselves. Oral exposures result following grooming. 

Exposure of cats to some types of liquid potpourris can result in severe oral, dermal and ocular damage.

Liquid potpourri is a combination of cationic detergents and essential oils. Cationic detergents can cause extensive systemic and local effects at concentrations as low as 2%. Local tissue injury caused by cationic detergents resembles that seen with exposure to other corrosives. In addition, cationic detergents can cause systemic toxicity including CNS depression, coma, seizures, hypotension, muscular weakness and fasciculations, collapse, pulmonary edema, and metabolic acidosis; the mechanism of these signs is not known. 

Treatment of local exposure includes dilution with milk or water, pain control (opioids), GI protection (sucralfate slurries) and supportive care (antibiotics, feeding tube). Systemic signs should be treated symptomatically (i.e. fluids for hypotension, diazepam for seizures, etc.).

10.) Alcohol

Due to their small size, cats are far more sensitive to alcohol than humans are. Even ingesting a small amount of a product containing alcohol can cause significant intoxication. Cats are attracted to mixed drinks that contain milk, cream or ice cream (e.g. White Russian, alcoholic eggnog, Brandy Alexander). Ethanol is rapidly absorbed orally and signs can develop within 30-60 minutes. Alcohol intoxication commonly causes vomiting, loss of coordination, disorientation and stupor. In severe cases, coma, seizures and death may occur. Cats who are inebriated should be monitored by a veterinarian until they recover.

 Hope everyone has a safe and happy holiday season!