Table of Contents:

Stuff I read online this month

Skin tumors

Stuff I read online this month:
 
Liberal brains vs. conservative brains
 
It probably isn?t a good idea to publish this, but I am a liberal. So I was interested in a report on a recent study in the Chicago Tribune (note that this isn?t a scientific journal) which indicated that the brains of people who call themselves liberals operated differently than the brains of people who call themselves conservatives.  The basic difference based on this study was the ability to recognize a situation that was different than expected and to react to it quickly. With that little change noted, broad generalizations have been made about what it means, how liberals are less rigid but more disorganized and how conservatives are rigid and close minded. Of course, being a liberal, I have to admit that I was happy to be viewed as someone with an open mind.  
 
One link to this study: 
 
http://www.psycport.com/showArticle.cfm?xmlFile=bhsuper%5F2007%5F09%5F10%5FNFLK%5F0000%2D0519%2DKEYWORD%2EMissing%2Exml&provider=The%20Virginian%2DPilot%20and%20The%20Ledger%2DStar%2C%20Norfolk%2C%20VA
 
One of the more intriguing aspects of the reporting that I saw (not in the link listed above) was a summary that stated that the ?liberal? brains recognized input that wasn?t expected and didn?t fit the usual pattern while the ?conservative? brain tended to just ignore information that didn?t fit the expected patterns.
 
This basic idea of this particular difference got me to thinking about veterinarians and how they react to information input during the course of the day. I have worked with six associate veterinarians and several relief vets over the years I have been in practice. Each of them had a distinctive style when it came to making a diagnosis. To some extent, though, it was possible to see a distinction between them similar to one discussed in the article on brain differences between liberals and conservatives.
 
There are more than two groupings of diagnostic styles in veterinary medicine but then there are lots of points along the spectrum between being very liberal and very conservative, as well. However, there does seem to be a group of veterinarians who are very ?by the book? and who want the symptoms and the pet?s condition to fit neatly into niches for each disease or disorder. Unfortunately, life doesn?t work that way. The solution that this group often uses is simply to ignore the symptoms and laboratory data that don?t fit the diagnosis they prefer. While that makes them seem very secure in their diagnosis it does make it possible for them to easily overlook concurrent disorders or disorders that just don?t pay attention to the rules. 
 
There are also a number of veterinarians who look at all the symptoms and think of different scenarios that might cause all the symptoms, even the unexpected ones. This group tends to rely a little heavier on multiple sources of information and often has a hard time committing to a diagnosis. This last point, no clear diagnosis, is tremendously annoying to clients who feel that they should get a specific diagnosis for the money they pay for an office visit and lab work. In worst case scenarios this group of veterinarians simply can?t come to a diagnosis. They often succeed in treatment, anyway, simply because they also tend to be fairly willing to change medication protocols or treatment protocols when they don?t seem to be having success.
 
Of course, most veterinarians probably practice somewhere between these two extremes. I tend to have difficulty committing to a specific diagnosis but when I do I tend to defend it, even when there are some conflicting facts. I think that this puts me somewhere near the middle of the road in the way that I approach the diagnostic process. 
 
I get a lot of feedback from people using our website that is supportive of the approach that I take to medicine but it would be dishonest to say that I get the same feedback from my clients. Practicing in a rural environment tends to ensure that a large portion of one?s clients are conservatives.  My technician always tells me that I present too many options when I rattle off a list of possible differential diagnoses for a set of symptoms and that this confuses the client. In addition, she seems to think that the way that I sort through the lists in my head while discussing them out loud at the same time tends to make me sound and act wishy-washy.  This really does upset a significant portion of the people who come to our practice. 
 
On the other hand, when I think I am right I can be obstinate about it. For some reason people seem to accept this better even though I think that it is a problem.  People seem to like having a diagnosis their vet believes in, even when later on I have to admit it was wrong and that I?ll have to change course.  I don?t understand why it is more acceptable to have a diagnosis that is wrong than to have no diagnosis but treatment that seems to be working. The second scenario seems far better to me ? although to be honest, the conditions aren?t mutually exclusive. I have been wrong, but firm, about the diagnosis but still used a treatment that worked, or that didn?t interfere with the pet getting better, on a number of occasions. It may help your pet get better care if you think about what kind of veterinarian you are dealing with.
 
If your vet seems to have the liberal mindset you might have to help him or her stay on course while treating your pet.  You can do this in a number of ways but the simplest is probably just to pay attention to what your vet is saying and then to repeat back any diagnostic steps, treatment options or procedures that you thought might be beneficial or wanted to hear more about. Sometimes they have just temporarily left your vet?s thought process and it can be very helpful to call them back into play.
 
If your vet is of the conservative mindset you might have to ask leading questions, like ?what else might be going on with this set of symptoms,? or if you recognize a symptom being ignored in the diagnostic process asking ?which of these diseases might cause X symptom??

 
Five disorders human physicians miss frequently (CNN Health)\

 
The link for this article is  http://www.cnn.com/2007/HEALTH/conditions/09/26/ep.misdiagnosed.diseases/index.html
 
This is an article about human physicians and certain conditions they miss frequently. It is a short article but it also made me think about the similarities and differences between human and veterinary medicine. I wrote a VetInfo some time ago on common mistakes that veterinarians make but I didn?t think about how that compares to human medicine.
 
The five disorders listed as being easy to misdiagnose were:  1) aortic dissection 2) cancer 3) clogged arteries 4) heart attack 5) infection.
 
The reasons for missing these diagnoses seems to vary, to me.  Aortic dissection is more common that physicians probably think but still unusual enough that it is easy to overlook. If this disorder is a problem in veterinary medicine it isn?t widely recognized, which may be entirely due to the fact that pets rarely have post-mortem examinations.
 
Cancer is very common but doesn?t always produce obvious symptoms, making it necessary to constantly keep it in mind and to try to use preventative screening on a routine basis. When symptoms do occur they are often symptoms common to other diseases, or even non-diseases, such as feeling tired or losing weight.  Physicians must be very vigilant to pick up cancer early without going overboard and suspecting cancer in every situation. I suspect that cancer would fit on any list of common veterinary misdiagnoses, as well.
 
Clogged arteries are apparently a major cause of shortness of breath but so are obesity and lack of exercise, very common problems in humans.  It is easy to overlook a problem when the patient?s symptoms make it easy to assume that their problems might be solved by weight loss or increased exercise. Pets have common problems that can resemble more serious ones, as well.
 
Infections are often missed and they are often treated for when they aren?t the problem. This might seem strange at first glance, but it is likely that either mistake could occur. I?m not sure which error is more common but I suspect that they are about equal. There are a lot of possible infectious diseases and it is nearly impossible for any physician to be up to date on all of them. On the other hand, it is very easy to assume an infection is present, dispense antibiotics or other therapy and hope that the patient will call if they aren?t improving pretty quickly.
 
The advice for avoiding these problems included asking leading questions, asking for additional test procedures, assuming doctors don?t talk to each other (especially in situations in which doctors work in shifts) and keeping track of lab work that is done and asking for reports if you do not receive them in a timely manner.
 
Some of the things in this article don?t really apply well to pets but overall the advice is pretty good. It is easy to misdiagnose many conditions in veterinary medicine.  It is also common for veterinarians to assume that pet owners aren?t interested in paying for test procedures. It is very common for lab results to go unreported and sometimes this happens when the results are important for the pet owner to know.  In many large veterinary hospitals veterinarians do work by shifts during the day and must pass on information as they change shifts. If you are aware of the information, too, you can help to protect your pet from being overlooked.  If your pet is seeing a specialist, don?t assume that your veterinarian is getting a full report on your pet?s condition. Let your vet know how things are going.  If your vet is working with the specialist and your pet is seeing both doctors, take a little time to discuss progress and relay information with both vets to ensure they are on the same page when it comes to treating your pet. Don?t forget that much of the good advice for dealing with your physician applies equally well to your veterinarian.


Fake Acupuncture
 
It is funny how often we go to a veterinary seminar on a particular topic and then notice lots of information in the media about that topic. In September we went to a seminar on holistic medicine. The morning was largely spent discussing acupuncture. The veterinarian giving the seminar was sure that it worked and that it was necessary to understand how to place the needles and what to do after placing them.  However, an article, again on CNN?s web site, suggests that sham acupuncture, placing needles somewhat randomly, worked nearly as well as following the ancient guidelines for needle placement.
 
The research suggests that 44% of patients receiving sham acupuncture and 47% of patients receiving real acupuncture based on placing needles in the right places, got better. These statistics were compared to conventional treatments but there were so many listed that it diluted the effects of conventional therapy. None-the-less, conventional therapy only seemed to help about 27% of the population.
 
This study raises some interesting questions. Is it OK to just stick needles in anywhere and to call that acupuncture?  If not, is it necessary to review where needles were placed in the sham group to determine if those spots represent new meridians for acupuncture?  Finally, how much should you suspect a placebo effect in this sort of study? It may be possible that 47% improvement could fall completely within the expected ratio for placebo treatment based on other studies where it has been that high. If this is a placebo effect why did conventional treatments do comparatively poorly?  Are people just used to them and expecting failure or were too many treatment options included in the study to make this portion of the results significant? 
 
I think that it is particularly important to note that the pet owner is probably treated by the placebo effect but that the pet, who can?t anticipate the results of treatment probably isn?t as susceptible to a placebo effect. Despite this, I do think that some dogs do exhibit signs of a placebo effect for certain conditions, especially allergies and arthritis, in our practice. Some of this may be due to waxing and waning of chronic conditions but I really do think that some dogs actually seem to expect a benefit when we treat them or at least they enjoy any additional attention the treatment efforts entail. They really seem to get the benefit of a placebo effect, in any case.
 
I was taken aback during the seminar on holistic medicine by how often the speaker said that it didn?t matter to him what the specific diagnosis for a problem was, that acupuncture treated general areas of the body so all he needed to know was it was ?a hind end problem,? or a ?kidney related problem,? etc.  That was a little difficult for me to go along with. On the other hand, I wouldn?t have guessed that you could just stick needles in a patient randomly and help them, either.
 
I don?t know how to sort through the problem of placebo effect in animals. I hope for my patient?s sake that when their owners see improvement it is really there, at least most of the time.
 

Skin Tumors, Continued:
 
Last month I covered some of the common skin tumors in dogs and cats. This month I hope to finish covering the most common of these tumors.
 

Squamous Cell Carcinoma (SCC)
 
Cats develop SCC more commonly than dogs but it is a reasonably common skin tumor in both species. Squamous cell carcinoma is associated with sun exposure in both dogs and cats. Due to this it occurs most commonly in white or light colored pets with thin hair coats. This is especially true for cats. In dogs there is presumptive evidence that SCC is also associated with papilloma (wart) viruses as nearly 50% of dogs with SCC have evidence of papilloma virus antigen.
 
The ear tips, nose and eyelids are the most common sites for SCC to originate in cats.  This cancer is not as likely to be confined to particular areas of the body in dogs, occurring on the trunk, legs, scrotum, nose, lips and toes most frequently.  When this tumor occurs near toes it usually causes swelling, discomfort and deformed nails. It is important to keep it in mind as a differential diagnosis when treating what seems like an infection in a toe.
 
Squamous cell carcinoma can be ulcerative or proliferative. In the case of ulcerative lesions it really looks like tissue is just being eaten away.  Our clients often have a hard time relating this appearance to cancer. It is not unusual to see a cat whose ear tips or nasal planum are simply missing, with scabby edges around the remaining portions of the ear or nose.  Proliferative forms of SCC can look a lot like warts but are often ulcerated and bleeding.  Dogs seem to be a little more prone to proliferative SCC and cats to ulcerative SCC based on our practice experience but I have not seen statistical evidence to support that claim.
 
When it is possible to remove the cancer and a wide margin around it surgery often results in a good outcome, greatly increasing survival time for patients iwth SCC.  I have clients who balk at removing the entire nasal planum but it works well enough to prevent recurrence of the cancer in some patients that I think it is reasonable to consider. Amputation of the ear flap when this tumor occurs at the tip of the ear is also very successful at preventing spread of the tumor. The larger the tumor is when surgery is performed, the worse the prognosis. 
 
Squamous cell carcinoma occurring in the oral cavity has a bad prognosis even with aggressive surgery. If an attempt is made to treat oral SCC through the use of surgery it is very important that it be done appropriately. This is a surgery that is usually better to have performed by a board certified surgeon, preferably one with an interest in cancer surgery.
 
There is a precancerous stage of SCC that is referred to as actinic keratitis.  At this stage there is often hair loss and the skin surface may appear to be irritated or scarred. It is possible to treat actinic keratitis with cryosurgery (freezing the tissue) or laser ablation so there are distinct advantages to recognizing the precancerous lesion.  It can be a little difficult to do cryosurgery on the ear tips without causing holes in the ear or loss of portions of the ear, though.
 
The prognosis for SCC in both dogs and cats is very dependent on the location and size of the lesions .  When SCC occurs in places in which it is possible to remove the tumor and a good tissue margin, surgery tends to cure the problem. The hardest thing for most pet owners is acceptance of the fact that an altered appearance, while not normal, can still be acceptable. If it is not possible to completely remove the tumor surgically radiation therapy may be an acceptable alternative, although availability of this treatment is limited somewhat. The prognosis is much better when these tumors are treated early enough that complete surgical removal is possible, though.
 
Dogs and cats get a form of squamous cell carcinoma called Bowen?s disease. This is the presence of multiple (usually) small pigmented sores on the skin that are often crusted over or that bleed easily. In cats these lesions are easy to mistake for military dermatitis and feline acne. Miliary dermatitis is the name for the disease process that causes multiple small scabs to form, often around the neck or face, as a reaction to allergy in cats. Bowen?s disease is resistant to treatment because new lesions tend to form after surgical removal of existing ones,  but often it will not cause really serious problems for years.  This is one thing to consider if your dog or cat has small lesions that resemble allergic skin disease but which fails to respond to treatment for that problem.

 
 Perianal Gland Tumors
 
The perinal gland tumors occur as benign tumors (perianal gland adenoma) and as malignant tumors (perianal gland adenocarcinomas). As you might expect from the name, these tissues arise from the smooth specialized skin around the anus. They are more common in intact male dogs but can occur in female dogs or castrated male dogs on occasion.  Most of the time these occur as solitary tumors or as a cluster or two or three lumps around the anus but they can occur in larger numbers.  These tumors are also sometimes found on other parts of the body, especially the prepuce of intact male dogs and around the tail region.
 
These tumors can be completely removed despite their location. If the tumors are very large it can be helpful to castrate male dogs and wait a few months for the tumor to decrease in size on its own before removal. It is acceptable to use laser ablation or cryosurgery to remove small perianal gland tumors. This does not appear to lead to problems with them recurring or to lead to metastasis of the tumor to other areas of the body.
 
Since perianal adenomas occur most commonly in older dogs often the hardest thing about dealing with them is convincing a pet owner who obviously did not want to consider neutering their dog that castration is now in its best interest.  The prognosis for both benign and malignant perianal gland tumors is better with castration.  If these tumors recur after castration, or when they occur in older female dogs or neutered males, it is a good idea to consider the possibility that the patient may have hyperadrenocorticism (Cushing?s disease) as this condition can lead to the production of steroids that mimic the effects of testosterone.
 
Some tumors really seem to require removal by a surgical specialist but perianal gland tumors really do not require this in most cases.  The location of these tumors makes some of my clients think that surgery would be impossible or that high complication rates should be expected but this has not been the experience at our practice.

 
Fibroma, fibrosarcoma, vaccine associated sarcoma  (VAS)
 
You might have noticed earlier on that ?oma? appended to the descriptive name of a tumor, such as fibroma, tends to indicate a benign tumor. If ?sarcoma? or ?carcinoma? is appended to the name the tumor tends to be malignant. This nomenclature holds true for this series of tumors, as well. 
 
A fibroma is a benign tumor arising from fibroblasts, cells that normally help in skin repair.  We see these most commonly in golden retrievers and Labradors as lumps on the top of their head but they are also supposed to be common in Dobermans and boxers. Unlike many tumors, fibromas seem to have  a predilection for younger dogs. It is a good idea to biopsy these tumors to confirm that they are benign. After confirming this the tumor can be left alone if it isn?t causing problems or doesn?t look too bad or it can be removed. Most of my clients seem to want to remove them simply because they get tired of people commenting on the bump between their dog?s ears.
 
Fibrosarcomas are malignant tumors that occur in both dogs and cats. These tumors tend to occur most commonly in the oral cavity in dogs but can occur in the skin and subcutaneous tissues. In cats fibrosarcomas are more likely to be a skin and subcutaneous tissues. It is also critically important in cats to distinquish between fibrosarcomas arising on their own and vaccine associated sarcomas, which occur in vaccination sites or at other areas where the skin has been chronically irritated. These tumors tend to be more aggressive than fibrosarcmas.
 
Despite the fact that fibrosarcomas are classified as a malignant tumor, only about 20% of them actually metastasize to other sites such as the lungs. Most of the time these tumors just invade tissue around them but they do this very aggressively in most cases. This makes it very difficult to completely remove fibrosarcomas. It is essential to identify these tumors prior to surgery, if possible, and to consider having a surgeon who follows cancer surgery protocols remove the tumor.  The best chance to remove a fibrosarcoma is the first surgical attempt and it is necessary to be as aggressive removing surrounding tissue as possible, something that general surgeons just don?t do very well.
 
Vaccine associated sarcoma is a specific problem with tumors that strongly resemble fibrosarcomas but develop at vaccine sites. This has been a recognized problem since 1991. Cats are predominantly affected but instances of similar tumors have been seen in dogs and ferrets. It is also recognized that fibrosarcomas are attracted to other inflammatory processes such as metal plates used in bone repair, other types of injections and foreign bodies that have entered the skin. However, at this time, vaccine associated sarcomas are still the most common type of these tumors. There is a strong correlation between the use of killed vaccines containing an adjuvant and the development of these tumors. The incidence of tumors at vaccine sites remains undetermined but it thought to be somewhere between 1 in 1000 and 1 in 10,000.  Killed rabies virus and killed feline leukemia virus vaccinations have been the most likely to be associated with tumors, to date.
 
At the present time there are two vaccines available that may moderate the risk of vaccine associated sarcoma.  Purevaxx (tm) rabies vaccination from Merial (tm)  does not contain an adjuvant but must be given yearly. VetJet (tm) recombinant feline leukemia vaccine, also from Merial, also does not contain an adjuvant. It is injected using an injection device that shoots the vaccine through the skin rather than a needle. It is considerably more expensive than competing vaccines containing adjuvants but the cost may be worthwhile for pet owners concerned about vaccine associated sarcomas.
 
If the best chance for success in dealing with a fibrosarcoma is aggressive removal of tissue around the tumor at the time of the first surgery this is even more important for vaccine associated sarcomas. It is so important to remove a wide margin in every direction that you should be certain that your veterinarian will be aggressive enough to remove underlying bone, nerve tissue, muscle or other close tissue.  At a minimum this should include at least a 3cm margin in every single direction and many times more margin than that is necessary.  Most of the time it is far better to have a board certified surgeon with an interest in cancer surgery remove these tumors and to consider chemotherapy or radiation therapy as additional therapies after surgery.
 
Watch where your veterinarian gives vaccinations.  Write it down if you think you won?t remember it later. If a lump forms in the neighborhood of a vaccination site consider the possibility of this type of tumor. Insist on a biopsy of some sort to identify the tumor type. If it looks like a soft tissue sarcoma consider asking for referral to a cancer surgeon. Knowing where vaccinations were given is the key to this process. You may need to remind your veterinarian that a vaccine was given at this site in order to keep attention focused on the possibility of a vaccine associated sarcoma.  Don?t avoid necessary vaccines due to these tumors but consider being cautious and asking about safer vaccines and longer vaccine intervals, where appropriate.