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Retro virus? you ask.  No, it's not a virus from the fifties, but rather the term retro refers to the way the virus reproduces in the host's body.  The important feline retro viruses are the infectious agents that cause feline leukemia (FeLV) and feline immunodeficiency disease.  (FIV).

Both of these viral diseases are limited to felines.  The viruses can have a long incubation period, meaning that it can take a long time from the time of infection until they cause disease.  They do not survive well in the environment, and are easily killed by drying and disinfection.  They cannot be spread by casual or indirect contact, usually spread by direct contact with body fluids and associated with breeding and fighting.

The respective diseases have serious consequences, often rapidly fatal once a cat is sick.  While there is an effective vaccine for FeLV, there is not a good vaccination option for FIV.  Therefor, in both instances, the best thing is identification and isolation of positive cats.  Ill cats that are retro virus positive have a worse prognosis than negative cats.  

 So who should be tested?  All cat should be tested before they are introduced to cats that you already own. The  American Association of Feline Practitioners recommend that all new cats be tested prior to introduction to a house hold or a cattary.  Because of long incubation times, they should be retested 60 days later and contact between the newcomer and existing cats be minimized during this time.  

Outdoor cats should be tested yearly. Indoor cats should be tested at least once as a screening and then periodically as determined by your veterinarian.   All sick cats should be tested, even if they are indoors and previously tested negative.  Testing of feral cats as part of a TNR project is optional.  However, there is value to knowing the retrovirus status of a colony.

Positive tests should be confirmed.  Healthy positive cats do not need to be put to sleep, but you should talk to your veterinarian about what you can do to keep positive cats healthy. 

While dogs have thyroid glands just like cats, and the hormone has similar functions in both animals, the diseases that these two species are generally the opposite.  Cats get functional thyroid adenomas, that is benign tumors of the thyroid gland that secrete active thyroid hormone, and hence cause hyperthyroidism.  Dogs get tumors of the thyroid gland, but these are usually thyroid adenocarcinomas.  Non functional, malignant tumors of the thyroid gland that can metastasize to other parts of the body.

Fortunately, thyroid cancer is not the most common disease of this gland in dogs.  Rather, decreased secretion of hormone, or hypothyroidism, is the condition that we see most often.

Hypothyroid dogs present just as one would expect if you think about thyroid hormone as the regulator of metabolism.  Dogs have low energy, poor hair coat, bad appetites, and often weight gain. If caught early, there may not be time for any symptoms to have become apparent.  

We include thyroid screening in our recommended blood work for all middle age and older dogs. It is important, because if caught early, simple supplementation with thyroid hormone on a regular basis will prevent clinical signs from ever starting.  I do want to emphasize that while many hypothyroid dogs are overweight, not all overweight dogs are hypothyroid.  So, just as with their owners, dogs with a weight problem often do not have a hormonal issue, it's an eating issue. 

The thyroid gland is a bi lobed structure in the front of the neck that is responsible for the manufacture and release of thyroid hormone.

The position is similar in dogs, cats, and people, but the more common diseases of this gland are different for different species.  For the sake of simplicity, I like to think of thyroid hormone as the regulator of metabolism. Too much thyroid hormone, and the metabolic rate goes up.  Too little, and the metabolic rate goes down.  

Today, let's concentrate on thyroid disease in cats.  We can talk about dogs next time.  Cats are prone to hyperthyroidism, an increase in circulating thyroid hormone.  It is a common disease in older cats caused by a benign tumor on the thyroid gland. If detected early, it can often be managed, or even cured.  Increased levels of thyroid hormone will cause an increased appetite, weight loss, rapid heart rate, and elevated blood pressure. Cats often present thin, often with a history of increased urination and intermittent, chronic vomiting. Most cases of this disease are easily detected with a blood test to measure the level of thyroid hormone in the blood, and if caught early, many of the complications of severe thyroid disease can be avoided.  One can imagine that prolonged, undiagnosed hormonal imbalances can cause serious disease. We see cats with heart and kidney disease secondary to uncontrolled hyperthyroidism.

Once diagnosed and underlying heath issues addressed, there are several options for treatment.  The gold standard is radioactive iodine therapy.  Performed at a specialty center, affected cats are given a single, painless injection of radioactive iodine.  This is preferentially taken up by the thyroid gland and it destroys the tissue.   The advantage is that cats that are good candidates for this therapy are essentially cured.  Ectopic thyroid tissue (tissue not found in the normal location) is also destroyed.  The down side is that cats need to be hospitalized in an isolation ward until their urine is no longer radioactive, usually 2 - 3 days, depending on your state's regulations.  It is also costly, and does require some pre treatment diagonsitics to make sure that this therapy is appropriate for your cat. Some cats become hypothyroid (low thyroid levels) after treatment. This condition is less serious but may require supplementation for the rest of the cat's life.

Radio iodine therapy has essentially replaced the less expensive, but riskier (and slightly less effective) surgical option of removing the thyroid glands.  This procedure, while still performed, requires general anesthesia.  In addition, if there is ectopic thyroid tissue, the surgery may not be effective.

Many clients opt for medical management. Methimazole, a relatively inexpensive medication, is given to the cat twice a day.  It blocks the incorporation of iodine into the active hormone at the sysnthesis level in the gland.  This effectively lowers the active hormone level and prevents the clinical disease from developing.  It does not remove the tumor, but since these are benign, that is not usually a problem.  The problem is that cats must be given medication twice a day for the rest of their lives and as we cat owners know, this may tax the owner/pet bond.  Most cats do not take kindly to taking medication.  Still, it is inexpensive and has the advantage of being reversible, that is if need be, the dose can be changed or the medication can be stopped.

This year, a new development in the treatment of hyperthyroidism in cats became available. Hills Pet Nutrition has launched a new iodine restricted diet for cats.  Since iodine is necessary to make thyroid hormone, this limited diet lowers the active hormone level in the blood.

 We are using this food for the three hyperthyroid cats in our hospital.  It has been well accepted in both the canned and dry forms and their thyroid levels seem to be normalizing, even off of their medication.  The food is not too limited, so other cats in the household can eat it, but we do recommend that they get a tablespoon of regular cat food on the side.  Cats that are being treated using this food can not eat any other food or treats because most of them contain iodine.

So make thyroid screening part of your cat's regular yearly health plan and if thyroid disease is found, early intervention will help your cat live a long and happy life.  You and your veterinarian can determine what type of therapy is best for your situation, but remember that early detection and intervention are definitely the best way to deal with hyperthyroidism. 

I know that most pet owners will be aware of what I am about to tell you, but since I've had 3 toxicity cases in the past week and I know that there are more out there, I thought that this is a good time to touch on this topic.

So we've had two cases of a sweat tooth resulting in potentially serious problems for dogs.

Looks good enough to eat, but this smooth, delicious treat has a potentially lethal component.  All chocolate contains methyl Xanthines  (think caffeine and related compounds).  Just the the taste and quality of our favorite treats, the amount of these chemicals varies with the type of chocolate.  Milk chocolate is the least dangerous, darker more bitter chocolates are more dangerous. You also have to be aware of the danger of cocoa mulch in the garden, but that is more of a concern in the summer than this time of year.

These compounds can cause excitablity,abnormal heart beats, and at levels of 60mg/kg, seizures.  As little as 4 oz of milk chocolate can cause moderate to severe signs in a 12 lb dog.  8 ozs of dark semisweet stuff can cause seizures in a 40 lb dog.  The good thing is that most of the chocolate that people have is the less toxic milk variety and usually is not pure chocolate, but rather it is filled with other stuff.  (yummy stuff usually)  As expected there is an app for i phones that will let you calculate the actual dose of methyl xanthines that your dog may have ingested.  It can be downloaded for free from the app store and is called choc tox. Even if your dog didn't eat enough for neurologic signs, you can expect an upset tummy with some vomiting and diarrhea.

Now, while chocolate seems to be mostly a dog problem, this next poison is one that I see in both dogs and cats.  Sometimes owners poison their pets by mistake and sometimes they do it to themselves. 

This was obviously a dog, and he pulled this bottle off the shelf and opened it himself.  Ibuprofen causes renal failure at 120 mg/kg in dogs.  It is extremely toxic to cats.  In addition to potentially fatal kidney shut down, it can cause gastric ulcers which can bleed or perforate.  This dog seems to have responded well to 2 days in the hospital on high doses of IV fluids, stomach emptying (yes we made him puke his little brains out) and gastric lavage with activated charcoal.  Plan is to send him home today and hopefully he will continue to do well.

If he were a cat, just a few of these pills would have been the last little things that he ate, because the dose would have been fatal. 

Speaking of cats and looking at the calendar:

No, I'm not being festive.  If you have cats, then NO TINSEL!  For some reason felines find it irresistible.  It is not digestible and can cause a nasty obstruction requiring surgery to remove the strands from the intestines or stomach.  While when caught in time this only results in an expensive, painful surgery and recovery, I have seen cats so sick that they cannot be saved.  So, while I haven't seen any tinsel trouble in the past year or so, I'm worried that my streak will be over soon if you guys are not careful.

Enjoy your holidays.  Keep the chocolate and hangover meds out of reach of your pets.  Enjoy an eggnogg or two for us, and have a happy and healthy holiday season 

I know that I've written about this topic in the past.  (OK distant past, and on a different blog), but it is important enough that I want to just touch on it for a brief moment here tonight.  Brief, because those of you that are fans of our Facebook page know that I already wrote a long and involved post complete with pictures and arrows and descriptions on the back but it was inadvertently deleted prior to posting.  While I recognize that it will take regular posting on my part to gain any type of readership and ability to reach the masses to help them better care for their pets, I don't have another long post in me tonight.

Why is this topic so important that I am writing about it again?  Well in the past month, we've admitted two cats to our hospital that were blocked for a long time.  One died of complications, the other was critically ill due to metabolic derangement secondary to his kidneys shutting down.  We did manage to pull that guy through, but not until after he blocked a second time in the hospital and needed a surgery to remove the penis, the enclosed narrow urethra, and all associated external genitalia so that he won't block again.

Cats block for a variety of reasons.  All are somehow related to the production of grit or mucous along with the narrow penile urethra and spasms of the lower urinary tract.  This combination, the perfect storm as it were, plugs the outflow from the bladder and prevents the cat from urinating.

As urine backs up, the kidneys stop working (reversible in most cases, preventable if the blockage is caught early), and the patients can become really ill.  Critically ill.  Not going to suvive ill.  So here are some things to think about.

Feed your cat a quality diet and make sure that there is adequate water available.  Cats are notoriously poor drinkers so it would be best if at least part of their diet is a canned food. Clean fresh water dishes and fountains, or dripping faucets will stimulate some cats to drink.

If your cat has a history of urinary tract problems, your veterinarian should recommend a prescription diet that will help prevent  relapses.

If your cat is straining to urinate, having blood in the urine, making frequent trips to the box, (litter that is), crying in the box, urinating out of the box, or generally doing anything out of the ordinary urination wise, you may have a problem.  If he can't urinate, there is definitely a problem, an emergency type problem.  Call your vet and if your vet is closed, get to an emergency vet.  Don't wait until Monday or even to the next morning.  The odds are, that if you are just noticing that your cat can't pee, he's probably had a problem for a while and may be on the precipice of a crises. 

 A good, but technical overview of this condition can be found on the ACVS website.  There are some graphic pictures of the urethrostomy surgery, but hey, they are surgeons.  I would make a joke about pictures of "kitty" naughty bits, but in light of what is going on out at Penn State, I will refrain.