Be Your Pet's Medical Advocate

Posted by Aaron

Sunday, November 22, 2009

I recently went through a spell of severe back pain and finally broke down and visited my physician. They were kind, listened to my concerns, prescribed some different pain management options, and then recommended that I go and have by back radiographed (x-ray).

Once I left the office, however, communication totally broke down. The doctor's office called the next day and said, "The X-rays are abnormal you need a MRI." I called the radiologist and was informed that the MRI was listed at $2,000.

I nearly pooped myself.

So I called back the doctor and I tried to get them to tell me what we were looking for, what was abnormal about the x-ray, and what kind of treatments we were going to consider. This was a lot of money. They were, unfortunately, totally unable to explain what they hoped to accomplish with this diagnostic, only to say that it was important and they needed to look at the "tissues." Seriously. $2000 and all I get from you is you want to look at the "tissues?" I was a bit upset.

I had the MRI (As it turns out, it was only $500 due to insurance negotiated discounts - who says our medical system of insurance ain't screwed up?). Afterwards my doctor's office called back to tell me that the MRI was abnormal and that I could be sent for injections for the bad disk if I wanted to. Seriously, that was the extent of the discussion. This left me even more frustrated.

I had to call back and insist that I talk to my RNP and discuss what the goals of thearpy were, what the expectations are for treatment, and what the actual diagnosis was. Point was, I had to GO AND SEEK OUT this information. I nearly had to drag it out of them.

I had to be my own medical advocate.

I have never had problems with this office, in fact I really like this group. I still like them, but they dropped the ball on this one.

I had seen the x-rays. I had a copy of the MRI made before I left the office so I was able to look through them and see what was up. I also had enough knowledge to know what we were looking for. What I did not know what how this would be handled in a human. I needed my physician's office to actually take the time to explain the plan. Why the recommendation for steroid injections? Surgery now? At what point do we consider it? Physical therapy?

Gee, Aaron, Why are you boring us with this long sob story about your back?

Because this experience was a reminder for me to NOT do this when I am working with my clients. I know this kind of thing happens every day both in human and veterinary medicine. It is easy to loose touch when the patient is not sitting in the room in front of you. I try very hard to keep up communication and take the time to explain, and I think I'm better than most. But I am sure that I have dropped the ball from time to time and have probably left some clients confused or with a feeling of being "out of the loop."

Your medical care and your pet's medical care is a TWO WAY STREET! It involves both the medical staff and you! I don't believe for a second that my doctor's office was trying to be lazy. But I do think that they did a terrible job this time communicating diagnostic findings, assesment of those findings, and a coherant plan with the patient. I had to take the responsibility to get the information.

You should handle your pet's medical care the same way. Hold your veterinarian and their staff responsible for giving you the information you require to make informed decisions. Make sure you are comfortable with the direction your pet's care is taking. If you don't understand something, call them back. Make for darned sure you have been given the information you need. We're all on the same team.


A Quick Influenza Update

Posted by Aaron

Thursday, November 19, 2009

I received an e-mail not long ago about a cat being diagnosed with H1N1 influenza. You will all remember that H1N1 is the "swine" flu as opposed to the H3N8 dog/horse influenza. I've checked into it and there have been a couple of cases of cats and a couple of ferrets with confirmed H1N1.

At risk of sounding redundant: DON'T PANIC!

We know that influenza virus can jump species. It's why we have the H1N1 epidemic to begin with, right? So it stands to reason that there would be instances where the virus jumps from people to cats.

Is it scary? Yes. It is. We always pay close attention when something like this happens. When there are inter-species jumps we always investigate and see if there is any difference in the virus, type of infection, or incidence.

Is it common? No, It's considered rare. I'm sure there are cases out there we don't know about, but if you consider there are two cat cases compared to many thousands of human cases, it's rare.

Has the virus mutated? NO. Genetic analysis says the virus has not changed, it just happened to infect a different species than we would have expected.

I assume we are going to see more of these. The cats and ferrets infected have all recovered from the infection and it is essentially the same story for them as it is in us or dogs.



The Deadliest Insect on Planet Earth

Posted by Aaron

Monday, October 26, 2009

I didn't forget my blog. I left the influenza post up a bit longer because I kept getting questions from folks about it.

We've had a TON of rain here lately and thanks to that, we've had a TON of mosquitoes. You may or not be aware, but the mosquito is considered the most deadly insect on Earth. Specifically, the female anopheles mosquito because she carries malaria. But there are many other genus of mosquitoes that are quite capable of transmitting other diseases as well.

Now, to be fair, the mosquito is not inherently evil. Annoying, itchy, and somewhat disgusting to look at, but the same could be said about so many of us from time to time. Mosquitoes get the bad wrap on this one because they are blood feeders and they feed on multiple hosts over the course of their lives. This means that they, in essence, swap blood from one individual to another.

Certain parasites have taken advantage of this biological fact. Malaria organisms hitch a ride with mosquitoes and infect another person via the mosquito saliva in an infected bite. Heartworm is another example. Larva are picked up with a blood meal, molt twice in the mosquito, and then infect the next animal through the bite wound from the mosquito. Most viruses can't hitch a ride with mosquitoes, but there are some notable exceptions - mainly West Nile Virus and the equine encephalitis viruses.

Different mosquitoes have different preferences in what they feed on. Some only feed on birds, for instance. Others will freely feed on anyone including dogs, cats, people, and horses. The feeding habits of a mosquito will decide what kind of threat that particular buggar represents.

I will often see outdoor cats with little crusted bumps on the ears and upper nose, and similar areas on dogs where the ears fold over or on the bridge of the nose. These can be little bites from mosquitoes or flies and may be an indication that repellent would be appropriate.

How to protect you and your pet:

Avoidance. Mosquitoes are active near dusk and dawn. They don't like to be out in direct sunlight and don't like high winds. If you are having a hard time with mosquitoes (like we are lately), then avoid keeping your dogs and cats out during that time.

The second line of defence will be repellents. There are fewer repellent options for dogs than there are for people. Any permethryn containing product will likely be repellent to mosquitoes. Bayer's Advantix and the Vectra 3D are examples of products that have "repels mosquitoes" on the label. I've also had folks tell me they've had good luck with the Avon Skin-so-Soft products. Spray a wipe and then wipe the fur of the dog, specifically getting the tips of the ears. In theory DEET should work, but I just don't think DEET is safe. You must wash it off and that makes it impractical for most owners on a day-to-day basis.

DON'T FORGET YOUR CATS! There are even fewer options for cats than for dogs. All of the permethryn products labeled for dogs will likely kill your cat, and that's just counter productive. There are pyrethryn products that may work, and the Skin-So-Soft trick may work. You must be more careful with all of the flea, tick, and mosquito control products in cats.

MOSQUITOES WILL GET INDOORS, TOO! Having an "Indoor only" dog or cat does NOT mean that their risk of heartworm disease is eliminated. All cats and all dogs should be on preventative year round - especially those dogs and cats living in more temperate climates.

The moral of the story is that many owners forget about mosquitoes if they are not outside being bitten. Mosquitoes happily feed on your pets and they do carry with them the potential for disease. Keep your pet current on preventatives and, if appropriate, use a safe repellent for your pet.


Canine Influenza - Yet ANOTHER flu bug

Posted by Aaron

Sunday, October 11, 2009

It is rather exhausting to hear so much about influenza. There is a fine line between caution and panic. The media has make this line difficult to identify. My goal here is to prevent as much fact as possible with an occasional injection of opinion.
Influenza is a HOT topic. When words like pandemic and enzootic are used it tends to make people very nervous. The moral of the story: Be cautious, be aware, but DO NOT PANIC.
The Virus:
The images above are all of influenza type A virus. Influenza A virus are further characterized by their H and N subtypes. Swine influenza is H1N1. Horse is H3N8. Seasonal flu is H3N2. The canine influenza that is causing all of the current panic is the H3N8 subtype of virus. This is because there was a jump at some point in history from the horse to the dog.
The current episode of canine influenza is dated to 2004 when there was a rather dramatic epidemic in a racing greyhound population that killed many dogs. Although we have seen influenza steadily since then, serum samples taken from dogs as early as 1999 have been positive for H3N8 virus. Those may have been previous jumps or they may represent the same virus we are seeing now. It's hard to know what used to be around when we weren't looking for it back then. All we can really say is what is here now and keep looking to know what is here in the future.
The disease is transmitted in exactly the same ways that the human influenza is transmitted. It's stinkin' contagious and is capable of spreading quickly through dense populations. Dogs infected with virus typically have a 2-5 day incubation prior to showing symptoms. They are then "sick" for a period of approximately 5 days. The cough may last weeks longer.
Dogs shed virus several days prior to showing symptoms. This is part of the frustration with the disease because dogs can infect others long before we even know they are sick.
The disease appears to be enzootic (permanently in a population) in Florida, New Jersey, New York, Colorado, and California. It has been diagnosed in 31 states (including Texas) but is still spotty in those states and has not been shown to be permanently in the population.
Transmission is most reliable in situations where a dog is in a larger population of closely housed dogs. This includes: boarding, grooming, dog shows, traveling with the family, dog parks, day care, and racing greyhounds.
Disease Symptoms:
Nearly every dog exposed will become infected. Of those dogs 80% will show some symptoms. Of those dogs 95% show little to no disease and what they do show is limited to:
Cough (deeper, chesty cough)
Mild fever
Nasal Discharge
5% of infected dogs will become more severely ill and those dogs may develop:
and in rare cases hemorrhagic disease and death.
Greyhounds appear to be exceptionally sensitive to the virus and they nearly always develop more severe disease.
These statistics are smackingly similar to human influenza, yes? I think most dogs are actually at lower risk of exposure than many humans. We humans are such social creatures and are always interacting with random members of our species. We touch door handles, shopping carts, phones, hands, and breathe the same air on public transportation. Aside from the dogs in the at risk population listed above, your dog is probably in a much more controlled environment than you are.
Supportive care. Plenty of water, controlled environment (don't leave a sick dog outside in the cold, wet weather), and watch closely. If the cough is severe enough we will use cough suppressants. If we are dealing with a very young dog, very old dog, or dog with history of cardiopulmonary disease, we may use an antibiotic. Notice how this sounds exactly like how we would treat any old "kennel cough?"
In a few, very sick dogs veterinarians have tried Tamiflu. There are no controlled studies to prove if this works and there are few dogs that are sick enough to warrant treatment. It is NOT recommended for prevention of disease!
Avoid high density situations if there is a local outbreak. Use common sense and if a dog has a cough - DON'T TAKE HIM TO THE PARK OR TO DAYCARE! My daughters have to stay home from school with a fever. Doesn't matter how good they feel. Any fever, vomiting or diarrhea and they have to stay home. It is encouraged that a child with a severe cough not be sent to school. Same concept goes for your dog.
And now the big question: What about the vaccine? Not to sound too redundant, but this is yet another hot topic. Here are a few facts about the vaccine:
  • It has only existed on the market for a few months. It looks like it will be a safe vaccine, but it's still new.
  • The vaccine is not labeled to prevent disease or eliminate infection - it is designed to reduce severity of clinical signs, shorten disease course, and reduce shedding of virus
  • It requires an initial dose followed by a booster 2-4 weeks later. It must then be boostered annually.

As with any vaccination of its type, protection will not happen until around 10 days AFTER the SECOND vaccine. So you must plan ahead if you want your dog "protected" prior to entering a boarding facility. You need a MINIMUM of 24 day lead-time and closer to 5 weeks is recommended.

Which dogs should get the vaccine? High risk dogs (see the above list) and especially high risk dogs traveling to or living in the areas of NJ, NY, CA, CO, or southern Florida.

Your veterinarian may have identified a local outbreak of influenza and may feel that vaccination for your pet is important regardless of where you live. Always follow your primary care veterinarians recommendations regarding what vaccinations are recommended for your pet.

I don't have statistics regarding the H3N8 in other countries. I would imagine it is in Canada and Central America, but nobody has mentioned this on my discussion boards. I'll keep looking.


New Guestbook

Posted by Aaron

Saturday, October 10, 2009

Check out the new Guestbook. Please sign in so I know where you are visiting from. Comments always welcome (especially if they are positive)!


Baby Heartworms - Video

Posted by Aaron

Friday, October 9, 2009

I had a heartworm positive dog come see me today. We checked for microfilaria (baby heartworms) and in one drop of blood there were dozens of them. I shot a couple of quick videos. The little worms are easy to spot. They literally are little round worms and they wiggle just like an earthworm. All of the red dots around them are red blood cells. Some of the red cells are stuck together, but on one video it is easier to make out individual red cells. The worm is just a bit thinner than the diameter of a red blood cell.



Honking Dogs - The Kennel Cough Complex

Posted by Aaron

Thursday, October 8, 2009

A cough can be caused by different things and can sound different depending on what causes it. For instance, a deep, productive, wet cough may be more typical of pneumonia (in the UK, I saw this referred to as a "chesty" cough). Tracheal irritation will cause a typical "goose honk," non-productive kind of cough. Debris on the larynx (like post-nasal drip or laryngitis) will usually cause of hacking kind of non-productive cough. (Think croup in children)

I wanted to specifically mention Infectious Tracheobronchitis (ITB), a.k.a Kennel Cough, a.k.a. Contagious Canine Cough Complex. The names alone should suggest that it is not as simple as a single bacteria or virus causing it. We are talking about a complex of diseases.

The most famous culprit is Bordetella. This bacteria is WICKED contagious and can cause all kinds of upper and middle respiratory issues. It is a very close cousin to whooping cough in people. Other known causes of the ITB complex include:
Strep equi (var zooepidemicus)
Canine herpesvirus
Canine respiratory coronavirus
Canine influenza virus
Canine adenovirus type 2
Canine distemper virus (CDV)

The above list includes a paltry three bacteria with the rest being viral. The most common cause of all appears to be the parainfluenza virus. Bordetella is often blamed, but is not often the cause. It is also important to note that these viruses don't always act alone. A co-infection with bordetella when you already have parainfluenza can cause a nasty infection where either alone may be harmless.

Because ITB is infectious, it is most commonly associated with animals in a high-density setting. This includes boarding, grooming, shelters, play parks, daycare, or dog shows. HOWEVER, because it's so stinkin' contageous, it's not uncommon for me to see a dog with typical "kennel cough" that has not stepped foot in a kennel in months! Cats or dogs coming through the yard, visiting dogs coughing on the fence, or dogs sharing a patch of grass at the park or in the apartment building shortly before your dog does can all be sources of infection.

When I am presented with a dog who is otherwise healthy (no history of respiratory, cardiac, or immune system disease) and ONLY has a tracheal cough, I rarely treat with antibiotics. If they are very young, very old, or have other issues, I may use an antibiotic. Why? Because the infections are nearly always self-limiting. If I treat with an antibiotic, the patient will nearly always get better in 5-7 days. If I don't use an antibiotic, they patient will nearly always get better in 5-7 days. There are exceptions to every rule, and if the patient isn't responding or gets worse, I will intervene earlier.

I try to reserve the use of antibiotics to only those times I feel there is evidence that antibiotic use is necessary. The goal is to prevent antimicrobial resistance. For me, that's a pretty danged important goal.

That's how I handle it. I have many colleagues that treat all coughing dogs with antibiotics and I can't fault them for it. The argument for antibiotics include:
1) It can't hurt
2) The problem may resolve faster with antibiotics
3) I can't prove it is viral, so I should protect against the possible bacteria that can cause more severe infection.
4) That doctor's local population of animals seem to get particularly nasty infections and regularly require antibiotics.

Because these guys usually have WICKED coughs, I will give a cough suppressant to help everyone get some sleep. The most effective cough medications are narcotics (i.e. hycodan), but there are others that may work well. Our supply of narcotic cough medications has been dicey at best over the past few years, so we use what we can when we have it. An alternative to hycodan if it is not available is tramadol.


Here's a hot topic! We can vaccinate for Bordetella, Parainfluenza, Influenza, and Adenovirus. None of these vaccines are perfect and we consider them likely to protect against severe disease, but NOT ALWAYS protective against infection. There's just too much variation in the wild-type bacteria and viruses. So YES, a vaccinated dog can get "kennel cough." It doesn't mean the vaccine wasn't given correctly or failed. There are just too many variables.

The influenza vaccine is new and in my opinion, the jury is still out on whether it will be worth using much. I've had two requests to blog on influenza virus. I'll get the rest of my data together and post on that one soon.

How often should a pet be given a "bordetella" vaccine? That depends. Some vaccines peter out after 6 months. Some have been proven to last one year. The most common protocol you will find is every 6 months. Even when I was using a vaccine that I felt worked for at least one year, groomers and boarding facilities required it every 6 months. I disagreed with them, but I was just the doctor. It's their facility. Is it hurting to give it every 6 months? Doesn't appear to be, but this goes back to the discussion of how many vaccines are enough and how many are too many.

Religion, Politics, and Vaccination - topics never to be discussed in mixed company ;)

Moral of the story:
I have LOTS of cases of "kennel cough" come to me every year. Most are viral, some are bacterial, and (in my hands) nearly ALL of them go home with cough medications only. A few end up with antibiotics. Think of it as the common cold for dogs. You just have to ride it out. Annoying, but rarely more than that.


Pill Poppin' Pets

Posted by Aaron

Tuesday, October 6, 2009

Now that we know more about how and why pain happens and is perceived, we can talk about how to treat pain.

Different types of pain come from different places. Remember the pain starts at the receptor somewhere out in the body and is then carried upwards towards the brain with a couple of junctions along the way. Depending on the patient, nature of the pain, and duration of the pain, we may change exactly how we treat different pets with similar problems.

Classes of drugs:
Local anesthetics
Lidocaine, bupivocaine, carbocaine are all examples. These drugs work by short circuiting the nerves carrying the signal. If they can't generate an electrical charge, the signal never makes it upstream. This can be done locally (like the spray you spritz into your throat when it's sore) or injected near a nerve (like when we do ring blocks for declaw procedures) or into the spinal column itself. Anywhere the drug goes, there will be no pain sensation generated. These drugs don't last long. For instance, lidocaine only lasts a couple of hours. Bupivocaine lasts about 12 hours when injected.

Non-Steroidal Anti-Inflammatory Drugs. These are drugs like ibuprofen (for PEOPLE ONLY), carprofen (Rimadyl), meloxicam (Mobic, Metacam), and ketoprofen (Ketofen, Orudis). This is a class of drugs that is very popular because they work well and are available over the counter on the human side. NSAIDs work by blocking the enzymes that generate pain causing chemicals and decreasing the amount of pain generated. NSAIDs work out at the SITE of where the pain is starting. NSAIDs are usually our first-line pain medications for osteoarthritis, post-operative pain control, and trauma pain management. They are often used in conjunction with a narcotic.

CAUTION: NSAIDs are a class of drugs that can be fantastic in dogs and cats, however, they must be used with caution and ONLY under the advice/supervision of your veterinarian. Cats in particular are sensitive to this class of drugs. DO NOT GIVE ANYTHING OVER THE COUNTER WITHOUT FIRST TALKING TO YOUR VETERINARIAN.

Also referred to as opiates because most all of these either came from or are related to opium and its derivatives. Opiates function in large part in the spinal cord. They decrease the amount of pain signal that is allowed to jump from the nerve carrying the signal from the periphery to the nerves in the spinal cord. They work in a couple of other places as well (brain).

Opiates are fantastic for all kinds of pain, from mild to severe. Opiates also have the unfortunate side effect of being prone to addiction because of the change in brain chemistry that happens with chronic use. Because they simply block the receptors in the central nervous system, the receptors can respond by making more of themselves. This means it takes more drug to work. We refer to this as tolerance of the drug. We have to increase doses to match. Bigger doses, longer term use and we're now talking addiction. Addiction does happen in our pets. It "looks different" because your dog won't loose his job, family, house, and friends over addiction, but the underlying physiologic response is the same - the body NEEDS the drug after it has had the drug for a period of time. Long term use of opiates must only be done under the direct management of your veterinarian.

Opiates are frequently combined with NSAIDs (think Percocet, Vicoden). This accomplishes two things - first, it provides two modes of pain control in one pill. They ALWAYS work better together than either one will work alone. It also makes them hard to abuse because the more NSAID you take, the more likely you are to have problems with the NSAID. It also makes it hard to cut the drug for street sale.

Opiates are all Scheduled drugs. This means the DEA tracks each and every tablet and drop of narcotic produced in the USA from the manufacturer to the patient. Your veterinarian has to keep lots of records on controlled/scheduled drugs. The more likely a drug is to cause addiction or abuse, the more tightly the DEA is in control of it.

Tramadol (Ultram) has become a darling of veterinary medicine. It is not a narcotic, but is narcotic-like. It also has some nifty effects in the brain where it increases seratonin levels. So even if you're in pain, you don't care (sort of). Because it's cheap, effective, and not controlled we veterinarians LOVE the stuff. Rumor has it that tramadol may become a controlled drug. We'll see. We'll still use the heck out of it, but it will make our lives a bit more difficult.

Amantadine and Gabapentin
Amantadine and gabapentin are medications that are used along WITH other pain medications. Both of these (although through different actions) help to change the way the brain and spinal cord react to CHRONIC stimulation of pain pathways. Chronic pain can cause these pathways to be "turned on" all of the time. Over time, these pathways can be permanently turned on or can be so freaked out that they don't know how to tell the difference between a little pain and a lot of pain. In some cases of chronic pain, amantadine can bring huge relief where our usual arsenal of drugs isn't cutting it anymore. These drugs take time to work and aren't used in the acute "I gotta have pain control NOW" setting.

Multi-modal pain control:
This concept means that we try to attack pain from different angles. When I am doing a painful procedure to a toe, for instance, I may do a local block at the level of the toe to try and block the signal from starting. I will also use a narcotic at the time of the procedure to help block any signal that makes it past my local block. I'll also give an NSAID so that when the local block wears off, the NSAID has had time to block the inflammatory chemicals from being made and the patient is, in theory, not painful. I've now blocked the pain signal at just about every available level. By using all three, I can use less of each and have a much better effect than I would by using only one drug alone.

There are literally entire books published on this subject, so I'm not trying to cover it all. Just trying to give you more information.

One last thing:
Some veterinarians still offer pain medications as "optional" after surgical procedures. Others make it a requirement. I require it and without fail I would have a few owners get upset that they were being sent home with pain medications when the pet didn't "look painful." 99% of the time, the complaint is that they have been asked to pay for the medication. Remember that pets don't show pain the way we do. They may be in significant pain, but not show it in an obvious way. Painful animals usually rest more than usual, have trouble getting comfortable, have increased breathing and heart rates, may refuse to eat, and may be more aggressive than usual. Cats are especially bad about hiding pain. They will seem to just be sleeping more than usual, when they are actually in quite a bit of pain.

Because it's nearly impossible to predict which pets will be more painful than others, we should ALWAYS TREAT THE PET AS IF THEY ARE PAINFUL. If pain medications are optional for you - TAKE THEM!!!!!!!! If they aren't optional - TAKE THAT AS A SUGGESTION AND USE THEM AS DIRECTED! Bone pain/amputation pain is usually the worst, followed by supporting muscle pain, neurologic pain, and organ pain. Trust me, after I have removed your dog's uterus, she's painful. After a de-claw (amputation), I can GUARANTEE your cat is painful.

Well controlled pain = faster healing time (well documented that this is true!), less stress, lower stress hormones, less susceptibility to secondary infection, and a happier pet!


OUCH! That Hurt! Pain Perception and Control

Posted by Aaron

Thursday, October 1, 2009

In this post we'll talk about what pain is and how it is perceived. Next post I'll talk about some specific pain medications and methods for dealing with pain.

We've all felt pain. Pain can be acute (cut finger, broken leg, twisted knee) or can be chronic (spinal pain, compressed disk, arthritis). Different types of pain require different approaches. I thought I'd do an overview of different types of pain management and talk a little bit about the way animals perceive pain.

First thing first. Let me say this loud and clear. ANIMALS FEEL PAIN.

All of us mammals are essentially wired the same way. The nerve endings, nerve fibers, and nerve junctions are all pretty darned similar. So a broken leg hurst no matter what species you are talking about. Where's the difference between people and animals?

Animals PERCEIVE pain differently than humans.

Even though we are wired the same, that signal has to be interpreted by the brain for you to have concious knowledge of that pain. This explains why I have seen many dogs walk into the emergency hospital DANGLING A LEG behind them. It is also why I've seen a cow get their horns sawed off and they walk right out into the field and start eating as if nothing ever happened.

There have been many excellent studies looking at pain perception in various animal species. Each have these have shown that animals definitely perceive pain. However, there is a difference in what kind of pain they perceive and what it does to their body.

Every individual is different.

Some people have a very high pain tolerance and don't seem to hurt too badly even though they have a broken arm. Others cry and are severely affected by a paper cut. This is also true in our pets. Some require more pain medication than others.

The Anatomy of Pain:

Pain perception starts at a nerve ending somewhere out in the body. Let's use the toe as an example. When the pain receptor is triggered (like the toe is squished or the skin is cut), those receptors fire off a signal to the spinal cord. The signal is linked in the cord to another nerve that sends the signal up to the brain. Once in the brain, the signal is perceived both consciously and sub-consciously. This is an over simplification, but the point here is that pain happens at multiple, yet different levels in the body. When considering the pain in the toe, there are at least three locations that I can treat to eliminate the pain being "felt" or "perceived" by the individual.

Ever had novacaine at the dentist? This is an anesthetic that numbs up the nerves at the sight that the medication is given. That way, the nerves never get a chance to fire.

Ever taken an ibuprofen? Drugs like this work by keeping the chemicals that stimulate the pain signal from being produced. The idea is that if you decrease the chemicals, you eliminate the pain signal all together. In other words, by cutting inflammation, it reduces the stimulation of the signal, and reduces pain. (NSAIDs, COXIIB)

Ever had morphine? Narcotics main action occurs in the spinal cord, although they do a fair amount in the brain as well. Narcotics keep that signal from jumping from the nerve that sent the signal to the nerve that carries the signal to the brain.

And then there are the drugs that affect the brain chemicals that make us either more sensitive to pain or take away that sensitivity. In other words, they help change whether or not we give a damn that we're painful.

So in people and in animals, there are many, many different places that pain can be modified. This helps explain why there are such different responses from different individuals. Depending on your body chemistry, your brain chemistry, your specific genetic make up, you may have more or less sensitivity to pain. Cows are NOT as sensitive to pain as poodles. It's a fact. They both FEEL pain, but they don't PERCEIVE it the same.

Acute pain is handled differently than chronic pain. Over time, these pathways I've described above can become hyper-active or can be blunted. So chronic pain may require different targets to get the pain response to either shut down or start up. Acute pain can be easier to manage for this reason. The pathways are more predictable and we can use drugs in the short term (narcotics that sedate) that wouldn't be smart to use long-term (narcotics and addiction).

I'll stop there for now. Next post we'll talk about specific pain medications and how they can help.


Puppy Hypoglycemia

Posted by Aaron

Wednesday, September 30, 2009

Glucose is the blood sugar that circulates around the body and it is the principle nutrient that your body’s cells use for energy. The liver stores extra sugar in the form of a starch called glycogen. Your body can then use this glycogen to make extra blood sugar between meals to keep the levels of sugar in the blood stable.

Livers of toy breed puppies aren’t very good at making glycogen. This means that they are susceptible to having their blood sugar drop if they don’t eat. This drop in blood sugar can be severe. Their livers are usually able to make normal levels of glycogen by the time they are 12 weeks or so.

Signs of hypoglycemia include:

Lethargy, excessive tiredness, “drunken” appearance or walk, confusion, weakness, sedation, panting, coma, death

What needs to be done?

Hypoglycemia is an EMERGENCY and MUST BE SEEN right away. If it is after hours, please take your puppy to your local animal emergency hospital. Additional blood sugar must be administered and the blood sugar has to be checked frequently over the next 12 hours.

When you first notice a change in behavior at home, you can immediately offer food. If the puppy is too tired to eat, a small amount of corn syrup, maple syrup, or honey can be smeared on the gums. This is absorbed across the gums and can sometimes “wake them up” enough to eat. Either way – this puppy needs to be seen by a veterinarian!

How can I prevent hypoglycemia?

One major misconception is that feeding more sugar (like honey or syrup) to the puppy will avoid hypoglycemia. Sugars are used very quickly and do NOT help keep blood sugar stable. Additional sugar does not hurt the puppy, but is not helping.

The most important thing you can do is increase the frequency of feeding. Fats, fiber, and proteins will help keep the blood sugar stable between feedings. Toy breed puppies should ALWAYS HAVE ACCESS TO FOOD. Most toy breed puppies eat very little to begin with, so it is not the quantity, but the frequency that is so important. Some puppies do best when offered small amounts of food (a tablespoon of wet food for instance) five or six times daily. There should always be a small amount of a small, dry kibble to eat.


Cat in a Can

Posted by Aaron

Monday, September 28, 2009

Canned food - Why is this important?

Most cat foods have a fairly high percentage of their calories that come from carbohydrates. I'm talking about excellent, outstanding foods here, not mega-merchant crap. Carbohydrate sources are inexpensive, highly digestible, and shelf stable. They provide good nutrition and we have made good use of them in our foods. Carbohydrate sources include rice, corn, wheat, and oat for the most part. Each of these can be fantastic energy sources.


IF we are correct about cats requiring a lower carbohydrate diet, the best way BY FAR to do this is with canned food. Kibble is a baked product, right? It requires flour and water. So you simply can't get a kibble with low carbohydrates. It's against their nature.

Canned, on the other hand, allows more flexibility to play with it and as a result, canned foods are nearly always lower in carbohydrates than their dry counterparts.

What about my cat's teeth? I thought hard food was required for dental health?
We used to think that. As it turns out - it really doesn't matter. Canned or dry - pretty much the same dental issues.

Why people don't like canned food:
It stinks
It has to be put down fresh (I can't leave for a day and just leave a bowl full of food.)
My cat won't eat it
It produces too much packaging waste

All of these are true. Cats are texture driven, and if they have always eaten dry foods, it is very possible that they will refuse wet foods. It requires a period of time for them to adjust if you have to switch to canned foods. You must keep the food fresh and canned food tends to stink more. Oh well.

The other reason behind encouraging canned foods:
Water! Remember my post on the miracle nature of water? Most cats don't drink enough. Their genetic code is still left behind from their desert ancestors, and they just don't feel the need for water.

But water does all kinds of critical things for cats - the most important of which is that it keeps their urinary output high and that is one of the single most important aspects of treating lower urinary tract disease in cats.

So am I advocating canned food diets in cats? Probably :) The jury is still out regarding some of these points, but I think they make sense. Canned diets are probably going to be the best choice for any cat with diabetes, obesity, kidney disease or lower urinary tract disease.

Don't stress if your cat won't eat canned food, though. Some cats just won't.

And now for the disclaimer:
FEED THE CAT, NOT THE BAG OR THE BLOG! If your cat looks great, feels great, is a normal weight, and is doing well on the food they are on - there's probably no reason to change. BUT - if not, talk to your veterinarian. There are a lot of good foods out there.

Don't hesitate to feed wet food, though. Canned food will NOT do any harm if the formula is appropriate for the cat (kidney cats need therapeutic kidney diets, for instance). You would have no argument from me if you wanted to feed your cat canned food exclusively. Probably a good idea for most all cats. We'll see if the veterinary community still feels this way in five years...


Cats and Carbs

Posted by Aaron

Saturday, September 26, 2009

I recently attended a veterinary conference in Kansas City and was REALLY excited to get to hear one of the clinical professors from Texas A&M talk about feline nutrition, obesity, and diabetes. This is cool stuff. Cats are bad about storing mesenteric fat. This is the belly fat. Fat that gets packed around the intestines, kidneys, and liver. This is where most human men (including ME) tend to pack the fat in. So this is a subject close to my heart (or at least close to my pancreas).

Mesenteric fat is uber bad. Fat in the belly pushes up on your chest and stomach and causes difficulty breathing and stomach reflux simply because of its bulk. It also makes it difficult for blood to circulate around the lower half of the body and helps drive up blood pressure. As if all that wasn't bad enough, we have now found that mesenteric fat cells are also capable of producing lots of their very own hormones as well. But wait - it gets worse. Most of the hormones that these fat cells make actually encourage more fat production, cause inflammatory changes in the body, and increase appetite! How horrible is that!

Feline nutritional requirements:
It is becoming more and more apparent that cats have a much higher requirement for protein than we once thought. It is also becoming more apparent that cats have a much LOWER tolerance of carbohydrates than we thought. This probably goes back to the fact that cats are true carnivores and their prey are only made up of a relatively small amount of carbohydrate with the remainder being made up of fats and proteins. Our domestication and inbreeding of cats has muddied the nutritional waters, but the basic genetic code is still pretty close. Wild felids (cats) don't normally eat much carbohydrate.

So is too much carbohydrate bad for a cat? THAT is the big question right now. There is some good research that would suggest that increased consumption of carbohydrates actually encourage deposition of abdominal fat and upset the pancreas in cats. Remember that abdominal fat is the worst kind of fat.

So should we eliminate or severely restrict carbohydrates for our cats? NO! ABSOLUTELY NOT! Carbohydrates are essential to life. Severe restrictions in carbohydrate intake are known to be bad. The discussion here is all about balance. The best balance for a cat is different than the best balance for a dog. (And this assumes that we're talking about a 'normal' adult cat or dog. In cases of illness, very young, very old then everything changes.)

Here's MY OPINION based on what I've been presented: I think it is reasonable that we are feeding more carbohydrate than we should. It could start to explain quite a few things. I see waaaay to much obesity, diabetes, lower urinary tract disease, and renal disease in cats. I KNOW our current nutrition isn't perfect. It's damn good, but we've been missing something. I believe increased belly fat is absolutely associated with lots of bad disease. If increased carbohydrates are, in fact, the main cause of the increased belly fat, then we need to change up how we feed our kitties.

What am I recommending to my patients?
First things first - FEED THE CAT, NOT THE BAG. If your cat is an ideal weight with ideal body condition, then keep feeding whatever you're feeding.
However, in cases of obesity, pancreatitis or diabetes I am leaning towards lower carbohydrate, higher protein foods unless concurrent illness in the patient tells me not to. (Diabetic cat in kidney failure, for instance.)

Next post, I'll build on this discussion and talk about canned foods for cats and why that might actually be the best way to feed your kitty.


Herbicides and Lymphoma

Posted by Aaron

Tuesday, September 22, 2009

I guess I'll continue with my cancer theme here and briefly comment on a question I was asked the other day.

Do herbicides cause cancer?

Like all things - it's controversial. There has been some good work done to show that the herbicide 2,4-D is associated with an increased risk of lymphoma in dogs. There's also lots of work to suggest otherwise. (2,4-D is, by the way, a cousin of Agent Orange.)

As I mentioned in my post on cancer development, there is rarely ONE thing you can blame for causing a particular cancer. This is especially true for lymphoma. Genetics, chemical exposures, foods, and hormones are all associated. So the truth probably is that 2,4-D can probably cause cancer in a predisposed individual, but may not in another individual if all other things are equal.

I'm a believer that exposure to environmental chemicals like herbicides HAS to be related to our increased incidence of cancers (in general). Which ones to blame? That's the sticky part! I don't know. But since there is good research that shows 2,4-D is a likely suspect, I try to avoid it as much as physically possible.


18, 19, 20... Wow that's a lot of toes!

Posted by Aaron

Thursday, September 10, 2009

It's always dangerous to refer to something as "normal" or "abnormal." Normal is in the eye of the beholder, right? Instead, I will employ the word "typical" when discussing supernumeray feline phalanges.

In otherwords... Polydactyl cats.

When I was a new graduate I practiced in New England. I didn't appreciate it at the time, but there were a LOT of polydactyl cats in Connecticut. I did some research into this and it appears that polydactyl cats originated in England, probably in Wales. The genetics quickly found their way to Boston. The appearance of polydactylism around the New World appears to be related to when various governments began trade with Boston. Most sailors considered polydactyl cats lucky and they were therefore regular stow-aways on trade ships.

Remember - domestic cats, like horses, did not exist in the Americas until the dang europeans brought them. Horses became fairly popular, but I don't know how the native peoples felt about cats. My guess was that after we killed them all with Smallpox and stole their land, they were pretty reluctant to embrace our feline friends. Horses could be ridden and used to carry things for you. On the other hand, have you ever tried to get a cat to do anything USEFUL? Maybe if THEY WANT to do it or they think it's their idea, but they sure as hell won't do it because you ASKED them to do it. The phrase pack cat just doesn't sound as useful as pack mule.

But I digress...

The typical cat has 5 toes on each front foot and 4 on each rear. Grand total = 18. Anything more than this is polydactyl. Even if it's only one extra. Usually cats are polydactylier than just one extra toe and they are usually symmetrical. Most all of these guys are polydactyl on the front feet only.

The extra toes can sometimes be used as opposable thumbs. My nephew cat Thomas (named for Tom Thumb, not Tom Cat) uses his thumbs to play and catch with. He's practically simian with the things. I'm surprised he hasn't learned how to open the door with them.

The extra toes aren't always attached to the wrist by good bony joints. Sometimes the toes are kind of "floppy" and other times they are fully functional. The wrist is designed to have tendons and ligaments for 5 digits. Anything more than that and there usually isn't enough anatomy to go around.

I've had one person tell me that all polydactyl cats came from Hemmingway's house in Florida. Nope. He had a particular fondness for them and most of his cats were polydactyl, but that's all.

FYI - the current Guiness Record holder has 28 toes. That's impressive!


Male Calico

Posted by Aaron

Tuesday, September 8, 2009

Did you know that the gene for calico coloring in cats is sex related? Two copies are required and they both belong to the female. So only females can be calico.


You have an XXY male - also known as Klinefelter Syndrome in humans. Approximately 1 in 10,000 calico cats are male. That's the last published statistic I've found. Rumor has that they may be slightly more common, but either way - it's pretty rare.

XXY males also have the unfortunate side effect of being sterile. This means you can't breed more male calico cats. They simply happen at random.



Treats for Tricks

Posted by Aaron

Sunday, September 6, 2009

What kinds of treats are OK to give my dog?

Everything in moderation, and nothing to excess. -Aristotle

This is a pretty common question I hear every day in practice. Anyone who has seen me in person (especially in profile :P) would agree that I think treats are pretty important. We get into problems when we forget that they are TREATS and as such should not me a major part of our diet.
In my case - scoop of ice cream=good. PINT of icecream=BAD.
In your dog's case - dog biscuit=good. Handful of biscuits=BAD.

First and foremost, keep in mind that most biscuits and treats for dogs and cats are about as calorie dense as an equal amount of their kibble. I've had owners complain that their dog "only eats a cup of food a day" and are shocked that they have gained weight. After we really look at what goes into the dog over the course of the day, I find out that they get 10 mini-milkbones a day. That's nearly another cup of food!

Just walk down the treat isle at the local pet store and you will be shocked at the sheer number of different options. Notice that nearly all of them are marketed to you, not your dog! Does your dog really care that his food is in the shape of a bone? He eats poop, afterall. Would he like it any better if it were a poop shaped cookie?

There are an unfortunate number of treats that are much to hard to be safe. Nylabones (sorry Nylabone people) and dried beef bones are just plain dangerous. Same goes for ice! Your dog will bust a tooth on one of these. I believe Nylabone does make a flexible/squishy chew. That's OK.

Rawhide: One of the most popular treats. Dried cow skin. Cousins to this would be pig snouts/ears and bully sticks (dried beef penis - I kid you not). Rawhide can be a great treat IF your dog isn't an idiot and tries to swallow it whole. Rawhide does NOT digest once swallowed. Big chunks of rawhide will cause obstruction. Some dogs methodically chew and gnaw the strip down to little bits. Rawhide is great for them. These treats do absolutely nothing for the teeth unless they are enzymatically or antimicrobially treated. They simply turn to slimy wads of old skin. Pretty disgusting, but dogs love them!

Greenies (all all associated copy cats): Greenies were the chlorophyl treat that made all of the other "edible compressed starch" chewies popular. The original form of the treat was too hard and if swallowed in big pieces, would cause obstruction. The company has long since reformulated them and they are now completely digestible. Some dogs get diarrhea when eating a Greenie (or similar). This is probably the case with all treats, but Greenies seems to be accused more than others. Don't know why. Any of the compressed corn starch treats or compressed veggie treats are probably fine.

Table foods: Look below for a list of acceptable fruits and veggies. This section is specifically addressing table foods. We humans eat some very, very calorie dense foods. It doesn't take much "table food" to provide big-time calories to our pets. We MUST be careful with this one.

Fats: High fat items are dangerous for your dog. Steak trimmings, bacon, nut butters, and dairy butter are very effective triggers of pancreatitis. Pancreatitis can be exceptionally dangerous and even fatal. High fat foods must be fed in small quantities only if they are fed at all.

Bones: Raw bones are soft and can be great to chew on. You have the issue of microbial food safety, but the bones won't cause damage. COOKED bones are an entirely different story. Ribs, steak, hambones are all popular treats but should not be fed. Cooked bones have all of the fat and soft tissue cooked out of them and the result is that only the hard calcium matrix. This can not be chewed through. It's harder than a tooth and will break a tooth pretty easily. Once swallowed, cooked bones cannot be digested and can cause obstructions or perforations.

Fruits and veggies:
Pretty much any fruit or veggie is OK with a couple of major exceptions:

Grapes and raisins are expressely forbidden! Bad. Some dogs die of horrid renal failure after eating grapes or raisins. Others have absolutely no problems. So, NO GRAPES FOR YOU!

Onions and garlic (allium family veggies) are dangerous to cats. Dogs can handle small amounts, but you must be careful. Cats have acutally died from drinking onion soup broth. The reason for this toxicity is that cat red blood cells (and to a lesser extent, dogs) are very sensitive to the oxidative damage that allium species do to the surface of the cell. They get damaged, the body takes them out, and the pet ends up with dangerous anemia and expires. Onions-cats-bad.

Some favorites I've had people give: frozen green beans (or fresh - dogs seem to like the crunch), carrots (fresh - NOT frozen), celery stick, sliced apple, sliced pear, and red or green bell pepper.

Post a comment on your favorite treat for your pet. There are tons out there. I'll comment back if you'd like.


Cancer Treatment - How to kill the tumor and not the patient

Posted by Aaron

Friday, September 4, 2009

The title sounds a bit hard-core, but it's the truth.

Our last discussion was about how and why we get tumors. Some of these tumors become what we would refer to as cancer. Once a particular tumor has been identified and we know what we are dealing with, we can then begin discussing treatment.

The words radiation or chemotherapy often begin to evoke visceral reactions from owners. Most people have been exposed to the idea of chemotherapy or radiation because of a family member or friend who has battled cancer. Some chemotherapy and radiation options are pretty rough on the body. Some patients get very sick. But not everything that counts as chemo or radiation is hard on the body at all It really depends on the specific protocol.

In my opinion, it's all about QUALITY of life. Some would see it differently and say that QUANTITY is the more important half of the equation. I disagree. Quantity is nothing without quality. The sticking point becomes defining the point at which quality and quantity intersect at an acceptable point for YOU and YOUR PET.

By example, I am currently treating my own dog for stage 4-b lymphoma. That's about as bad as it gets. We decided to start chemotherapy because many of the initial drugs I was going to use in her treatment were fairly benign and it was worth a shot. Surprisingly, she's responded very well to her chemo and hasn't had any bad days because of it.

Until now.

I made the decision to go ahead and give her the doxorubicin. That is the one most likely to make her 'feel bad' for a few days. My decision to use that drug was based on the fact that a few days of nasty were worth the few weeks or months of happy. That was my take on it. Others would argue that the cost and misery of a few days is not an acceptable price to pay for a few weeks or months.

The take-home point is that the decision to treat and the decision how to treat is not something that can be made for you. Your doctor should give you options and you should consider the total picture and make an informed decision. For some, the answer is an easy. Hopefully you enjoy the support of a caring oncologist or primary care veterinarian and you will be an active part in the decision making process.

Staging the tumor:
Staging is something done when we are dealing with a malignancy (cancer). The goal of staging is to evaluate how 'badly' the tumor is behaving so that we can determine what therapy is required. It is necessary to help direct types of therapy in most cancers.

How we stage a tumor depends on tumor type. Some tumors tend to metastasize to the lungs first. Others met to a regional lymph node first. In the case of lymphoma we have to determine if the tumor is in the spleen, liver, or thymus and if it is in lymph nodes. Different locations have different prognoses because. Believe it or not - the same tumor found in two different places could behave dramatically differently.

If we are able to physically remove the tumor then we often take this as our first course of action. After all, why would we poison the entire body if we can cure the cancer by physically removing it from the body. There are many tumors where this is the ONLY treatment recommended.

Other times, our goal is to de-bulk the tumor. We know we won't get the entire tumor. We know there will be microscopic tumor left behind. But if we get all of the visible tumor, it makes the microscopic much easier to heal.

Because there is often microscopic invasion of the tumor in surrounding tissues, the amount of tissue to remove is sometimes impressively large. As an example, mast cell tumors require margins of approximately 3cm in every direction. By the time you account for the shape required to close the defect, a patient with a 1/2" mass may end up with a 6 inch incision.

Just like with real estate, it can all be about location, location, location. That same mast cell tumor on the foot simply can't be removed. There's not enough foot left to close the wound. So there are times that tumor location may dictate amputation of a particular body part (toe, ear, etc). Amputation doesn't have to be a bad word. Life without a toe isn't a bad idea if the only other option is death.

Radiation therapy means that energy in the form of radiation (gamma rays, x-rays) is poured into the tumor in hopes of causing such severe damage to the tumor cells that they die off. Unfortunately, normal tissues always get caught in the crossfire. There are some great new technologies that allow for the very precise delivery of radiation to a very tiny area and help minimize the amount of collateral radiation damage. Local reactions like burns (mild or severe) are the usual side-effects. When talking about the skin, that's not so bad. But if you are trying to irradiate a tumor in the pelvic canal, you end up burning the colon a bit, and the colon does not handle this very well. Again - Location, location, location.

Some tumors are particularly sensitive to radiation and die off quickly and easily. Some are very resistant and radiation doesn't really work. Radiation is usually applied to a very specific and focused location, but there are times where it is appropriate to irradiate an entire limb or an entire body. Whole-body radiation is something usually reserved for killing off the bone marrow in leukemia patients prior to marrow transplantation.

Chemotherapy - The 'other' Big C:
The goal of chemotherapy is to poison the body JUST ENOUGH that the tumor cells die but the patient does not. Chemotherapy is generally administered to the entire body. This is good if you have tumor around the entire body, but it also means that you are exposing all the normal cells in the body to the drug.

Nearly all chemo drugs target fast growing cells. This makes sense because the tumors are usually growing quickly. However, there are lots of cells in the body that have to grow quickly. Bone marrow, cells lining the intestines, and hair follicles are the major players. Not all drugs cause the same problems. For instance - vincristine is one of the drugs in lymphoma treatment. It is VERY well tolerated and is pretty uncommon to cause any issues. Doxorubicin, on the other hand, is quite likely to cause pretty severe gastrointestinal problems. In some dogs, it will cause balding.

The moral of the story is that you should not let the name chemotherapy scare you away all together. Some drugs are fairly simple and may provide excellent responses with nearly NO side effects. Others may be tolerated well in one patient but horribly in another. You simply have to weigh all the variables - patient, prognosis, finances, transportation, side-effects.

This posting does not even begin to cover everything. My hope was to at least cover the big picture. Like I say - I'm happy to entertain questions about specific tumors, drugs, or topics anytime. Just e-mail me!


The Big "C"

Posted by Aaron

Sunday, August 23, 2009

WOW - I just realized how long it's been since I posted. Sorry, folks. I could give reasons, but they'll just sound like excuses. Let's get back to work!

Cancer. This is a loaded topic and one for which there are entire textbooks. I'll discuss cancer treatment in the next posting. For now - we'll talk about what it is, why it happens.

First some definitions:

Tumor - a coherent overgrowth of abnormal cells. This can also be used as a pleural noun.

Mass - I use tumor and mass interchangeably. For me - mass is more accurate. I feel a 'mass.' There is a 'mass' on the shoulder. Mass does not describe the behavior of the cells.

Neoplasia - Anytime a group of cells starts growing in a way that is not 'normal' like the parent cells, it is neoplasia. So neoplastic cells aren't just overgrowths of normal cells, these are cells that have chosen to ignore convention and strike out on their own. Neoplasia can be benign or malignant. It simply means that it is a 'new growth' of cells.

Benign - This is an adjective (or adverb) that describes the behavior of the tumor. A mass that behaves, will not spread to other parts of the body is benign. Benign masses in bad places may do bad things (a benign tumor in the brain is still not a good thing to have - there's only so much room up there to deal with and the brain needs all the room it can have).

Malignant - The opposite of benign. This describes a tumor or behavior that is not going to behave. Malignant tumors are usually associated with something that will spread to other parts of the body or will invade locally. Malignant = bad.

Cancer - a term that is used interchangeably with malignant. Some folks use cancer to mean all tumors. Usually if you say cancer - you mean something that is bad.


How do tumors start?
Believe it or not - you have cancer. Seriously. Every day your body has a few cells in it that don't replicate like they are supposed to. They forget who they are. The don't listen to the body when the body says STOP. There is simply something WRONG with them. 99-100% of the time, the body recognizes these guys and sends in the killer-T cells. These white blood cells see the bad cells and then kills 'em. Kills 'em dead.

And then there is the exceptionally rare cell that survives. The body doesn't recognize that it is bad. It's allowed to continue growing because the body thinks it's supposed to. Next thing you know - there are a few billion cells and you have a mass, or tumor.

So what does it mean when I hear that some chemical or product causes cancer?
ANYTHING that damages cells or screws with their DNA could cause them to start behaving badly. If it brings about a change in the cell that would ultimately cause a tumor is referred to as oncogenic. Lots of research goes into this field.

There are oncogenic chemicals (saccharine, tar), radiation (sunlight, x-ray, gamma ray), and even oncogenic viruses (feline leukemia). Some of these causes trigger damage to DNA (radiation) that will cause random mutation and tumor genesis. Others cause certain genes in the cell to turn off or on and as a result the cell stops listening to instructions.

Some cancers have a genetic predisposition. Some individuals may be more likely to develop cancer because they either have a gene or lack a gene that regulates the cancer formation. We don't understand all of these genes yet, but it's a HUGE area of research.

You can try and prevent exposure to environmental triggers of neoplasia. You wear sunscreen, you don't use a tanning bed, you filter your water, are careful with household chemicals, eat healthy, and don't smoke. You can't control your genes. You were born with them. So you try not to piss them off and instead try to help the body recognize when they've gone wrong to catch a tumor before it kills you.

In humans, there are certain familial cancers. In dogs and cats, there are breeds that have been associated with particular tumors. Boxer dogs and golden retrievers are seriously over represented when it comes to cancer. So clearly these guys have something that either pre-disposes them to making a cancer OR something that keeps their body from catching the cancer once it's formed and killing it before it becomes self-sufficient.

What happens after the tumor is started?
By the time the tumor is operating on it's own, it is no longer listening. It's past the point where the body can stop it. It's like a petulant, super-independant child. The body can try to convince it to slow down, but it doesn't want to. It still gets all of it's energy from the parent, still relies on the body for a home, but doesn't care what's best for it's host. It's parasitic.

So now we have to think in terms of benign versus malignant. Benign means it usually won't invade and it will not spread to distant parts of the body. Lipomas, or fatty tumors, are good examples of this. Nearly anyone with a dog has seen a fatty mass. These usually feel soft, slightly squishy, and are just under the skin. These guys are benign. They aren't going to spread. However, they may not behave. If you get one in the armpit that decides to grow to the size of a melon you may not have function in that leg. Benign tumor - bad result.

Malignant masses are going to be locally invasive, aggressive, and may spread to distant places. These are the bad guys. The cancers. Malignancy typically means that we must intervene and treat or they will kill you. Next post I'll talk about different treatment options. Generally speaking, we're talking surgery, radiation, or chemotherapy.

These are just general principles. I can discuss individual tumor types in future posting. If you have a particular cancer/tumor that you want me to discuss, please e-mail or post so I can write on that topic. There are some really interesting tumor types out there that do all kinds of weird and horrible things to the body. There are simply too many to try and lump together.

I promise not to allow so much time to elapse between postings. Talk soon.


Avocado Toxicity

Posted by Aaron

Saturday, July 18, 2009

An owner called the hospital today and wanted to know if avocado is poisonous. Specifically, she wanted to know if avocado is poisonous to dogs.

Short answer - no. Dogs can eat quite a bit of avocado without problem. The pits are mainly a problem if they are swallowed whole and end up becoming and obstruction. Too much avocado = bad diarrhea.

Here's a quote from Dr. Mark Grossman:
Avocado does contain the toxin persin. The leaves, fruit, bark, and seeds contain the toxin. In dogs and cats however, it does not seem to be as much of a problem as in cattle, horse, goats, rabbits, birds and fish.
Signs including vomiting, diarrhea, death, inflammation of mammary glands of rabbits, goats, cattle, and horses are seen. As well as cardiac failure in goats with respiratory distress, generalized congestion, fluid accumulation around the heart.
A few cases of dogs becomming sick exist but they have to consume large amounts.

In other words - don't feed your goat avocado! Dogs - OK.

This has also come up because of a popular new food called Avoderm. Dasuquin also has avocado in it. It's OK. By all measurements, Avoderm appears to be a good food. Don't let the avocado part of it worry you.

Dr. H-

Follower Question - Hyperthyroid Feline and Proper Drug Choice

Posted by Aaron

Friday, July 17, 2009

Hello Dr. Herndon,
I've seen it mentioned a couple times in a couple places that injectable and/or all benadryl should be used with caution/not used at all in a hyperthyroid cat. But, I can't find out why or what to look for. Also can't find any info on benadryl's effects on CRF cats. [I have a 16yr old CFR (+peri-renal cysts)/hyperthyroid female that has some serious sinus issues, among other things.

My vet and I have been trying to find ways of dealing with it that don't torture the cat. She severely hates Afrin nasal spray. Saline drops don't seem to accomplish much. Today I stuck her in a cage "next to" a steam vaporizer for 1/2 hr--that seemed to help a little... At any rate, she has been on injectable benadryl since 6/20 at 0.05-0.07 mL/dose. Most days she only got 1 dose. On 7/4 she went off her food--nauseated style. Today received an anti-nausea and pepsid in the AM. She finally ate cat food around 5:30pm after the vaporizer session. She has other issues too so this could very well be unrelated to the benadryl, but wanted to check.]
Thank you so much for your time, Kelly S

I can't think of any good reason not to use Benadryl in a well controlled hyperthyroid cat. No worries there at therapeutic doses. It MIGHT cause the heart rate to increase a little. A cat in out-right heart failure might not do well with it, but I think you'll be fine.

Cats with upper respiratory congestion are difficult to treat. When a cat can't smell, a cat won't eat. When a cat don't eat, a cat gets worse. You're doing the right stuff. Here's a couple of suggestions to bring up to your doctor:

1) Consider having a PCR run to check for herpesvirus, calicivirus, and mycobacterium (PCR is a very sensitive test looking for virus or bacteria DNA). If this is viral, it may be smart to consider using an antiviral up the nose. There is an antiviral drug called idoxuridine that is sometimes used in the eye - I've used it once in the nose instead. If it's herpes, then you can also add the amino acid lysine to the diet - that helps slow the virus down. The other anti-herpesviral medications used in people don't work well in cats (acycolvir/valcyclovir).

2) I've sometimes used atropine ophthalmic drops in the nose (cats HATE THIS!) but that helps dry it up. I'll also mix atropine with an ophthalmic antibiotic drop. The antibiotics can sometimes help with secondary infection.

3) I've worked with a compounding pharmacy to have an antihistamine made in a trans-dermal gel. Transdermal gels are a substance you would smear on the inner surface of the ear. The drug then absorbs across the ear skin. Not all chemicals/drugs can do this, but the pharmacist can help your doctor find out what drugs might be worth trying.

Humid air helps - you are trying to break up the debris in the nose so the kitty will eat.

A 16yr old kitty with several major health issues is not an easy task. If she's feeling nauseous I'd have some bloodwork run. When the renal values get too high the toxins will cause upset stomach and mouth ulcers. Worth a check.

Dr. H

Heartworm Disease in Cats

Posted by Aaron

Saturday, June 20, 2009

Checkout this link. It has good information.

Here's the scoop - we always knew that cats could develop heartworms. We knew that occasional cats would develop an adult worm in the heart and that those cats were in a pretty dangerous position. If you tried to treat the adult worm, about 33% died outright, 33% were so sick they wished they were dead and 33% did great. Thankfully, the incidence of this disease was fairly low in cats and so prevention was recommended, but not encouraged as much as it should have been.

Guess what - we were wrong! Research completed at North Carolina State in 2005 confirmed that although true that few cats develop adult worms, the real story is that MOST cats kill the worm before it turns into an adult. That's great except that when this happens, these kitties often develop wicked asthma. I've treated dozens of cats for asthma. Feline asthma is considered a fairly common disease. We now know that many (most?) of those cats are heartworm disease!

Diagnosis of these kitties is difficult because of when they kill the heartworm larva. There is a very narrow window of time that a cat would be 'positive' on a test. By the time we see a sick kitty, it is quite likely that we will not be able to prove the presence of heatworm as the cause. Worse yet - our treatment at this point is supportive. I can't reverse the disease, I can only control it. There is now a name for this condition - HARD - Heartworm Associated Respiratory Disease. Heartworm is a misnomer in cats - lung disease is the primary problem, not heart disease.

So the major change in our thinking has been that PREVENTION is critical in cats. Many more cats are at risk that we ever though. Prevention is now seen as just as important in cats as it has always been seen in dogs.

But my cat is indoors. Heartworm disease is transmitted by mosquitoes, so how could my indoor cat be at risk?

There's the other shocking finding. In that same NC State study, roughly 30% of those cats diagnosed with heartworm disease (usually after death) were reported by their owners to be 100% INDOOR cats. So 1 in 3 cats dead of heartworms never left the house (according to their owners). We all know mosquitoes will get into the house. Now we have proof that they bring problems indoors with them.

Moral of the story?

Cat's get heartworm disease. Most frequently they get respiratory disease. Heartworm disease is often fatal in cats. It's hard to diagnose. It's hard to treat. It's also VERY PREVENTABLE if you use a monthly preventative prescribed by your veterinarian. Prevention, Prevention, Prevention, Prevention. My personal favorite is Revolution for cats. There are other excellent products like Heartguard, Iverheart, Advantage Multi, and Interceptor. Each of these have the added bonus of also controlling intestinal parasites.


Heartworm Preventatives

Posted by Aaron

Thursday, June 18, 2009

Now that I've talked about heartworm disease, here's the skinny on heartworm preventatives:

You now know that mosquitoes are the carrier for heartworm. Exposure to mosquitoes is therefore required. Risk is highest for dogs outdoors at the hours of dusk and dawn when the little buggars are out feeding.


Mosquitoes come indoors! Dogs go out to pee or at the very least poo (usually). Although your risk is lower as an indoor only cat - about 1 in 4 SICK cats are considered 100% indoor by their owner. There is no such thing as a dog that doesn't need preventative.

Preventatives are critical. One common misconception is that heartworm preventatives work for the NEXT month after they are given. What's happening is that the preventatives are killing off any larva that the pet has been infected with over the LAST month. In other words, we assume that the pet has been infected and the preventative is killing them before they grow to adults.

There are many different heartworm preventatives out there. They all do the same thing - they kill the larva. All of the preventatives you should be able to get today are in the same class of drugs. Some people are still using Filaribits (DEC) but if you are - STOP. Some preventatives have activities against other parasites - some kill intestinal parasites or fleas in addition to heartworm larvae.

Common products you'll find are:

  • Heartguard (plus)
  • Interceptor (or Sentinel)
  • Advantage Multi
  • Revolution
  • Iverheart (plus)

They each have really pretty literature that shows how they are the best product on the market and all of their competition sucks. The truth is somewhere in the middle. They all have their ups and downs. Go with your veterinarian's recommendation. I'm a Heartguard man. Always have been. Always will be. All of these products are effective. All of these companies support their product claims. It's really a matter of your situation, what you think is easiest, and what your veterinarian recommends for your area.

The most important concept is that they are all intended to be given once a month. You have to use them once a month. The one exception out there is ProHeart. This is an injectable heartworm preventative that is given every 6 months.


Heartworm Disease Overview

Posted by Aaron

Wednesday, June 17, 2009

The link above will give you lots and lots of good information on this subject. The pictures above are small, I know. I don't have any larger pictures. Maybe someday I'll get a good heart to get pictures of.

I'm going to post a separate blog on preventative choices, feline heartworm disease, and heartworm treatment.

Here are a few common myths and answers. There's discussion below.

Myth: Heartworms are found in the stool. Your dog gets heartworms by coming in contact with another dog's stool.

Fact: Heartworms are exactly that - they are found in the heart. The larvae are found in the blood stream and they are transmitted by mosquitoes.

Myth: Only dogs get heartowrm.
Fact: We used to think so. We were WRONG. Cat's do get heartworm. So do people.

Myth: My dog is indoors, so I don't need preventative. Same argument for cats.
Fact: Turns out this is absolutely false as well.

Myth: Preventatives are over the counter. My vet is just being a pain in the butt about requiring me to come in.

Fact: See my previous posts on the importance of regular physical exams. Preventatives are all PRESCRIPTION products. This means we can't just sell it over the counter or we get huge fines and risk loosing our license. We're not being a PItA. We're following federal drug law.

Here's the skinny on heartworm disease.

These worms start out as baby larva in an infected dog. These larva are referred to as L1 larva. A mosquito comes along, takes a blood meal that includes the L1 larva and flies away. The larva grow and develop into L2 and then L3 larva. Same mosquito bites another dog and those little L3 larva come down the mosquito's mouth and climb into that tiny hole and into the dog (cat, human, wolf, fox, etc). The larva then continue to devlop into L4, L5, then adult worms. As L5 and adults they take up residence in the right side of the heart and the pulmonary artery leaving the right side of the heart and into the lungs. You must have both males and females to reproduce, but once you do - the life cycle begins over again. Adults live for about 5 years in the dog.

The canid is the definitive host - meaning they are the host the parasite is intended for. Dogs, fox, coyote, wolf are all routinely infected. Other species can be infected with the parasite, but the body kills it off before it can become an adult. In people, it's usually killed off in the skin but it is possible for it to migrate to the lung and form a little granuloma before it's dead.

We used to think that cats were an uncommon host for the parasite - we were incorrect. See my companion post about cats and heartworm disease.

It takes about 4 or 5 months for a worm to go from larva to adult. The preventatives only work during the first 30-45 days of this period. Tests used by your veterinarian are only positive when there are adult female heartworms present. It is therefore possible to have worms in the heart and a negative test if either 1) they are only 4 months old or 2) you have all males or less than 3 females. 100 males, 1 female = NEGATIVE test! (This is uncommon, but it happens!)

The timing on this is important because this means there is a period of time between when a larva can be killed and when the test would become positive. For this reason, a pet that has been off preventative cannot be considered negative until a repeat test is done 5-6 months later.

What happens if I don't treat or prevent heartworm disease? Honestly, a dog can probably tolerate a small worm burden (1 or 2 worms) for a lifetime. The will have changes in the blood vessels in the lungs and will have chronic bronchitis-type problems. Most dogs with the disease don't just have one or two worms and therefore get progressively get sicker and sicker with hearts that fail and lungs that don't work. They may develop clots in the lungs and can suffer sudden death. Untreated heartworm disease kills. It's pretty nasty.

Next posts will be on prevention, treatment, and feline heartworm disease.