VetInfo Digest February 1998
This issue
What is good medicine?
Differential Diagnosis-
New Medications
Old Medications revisited-
Not a Large Animal Story-
What is good medicine?I think that one of the hardest things to define is "good medicine." There are many ways to define this term and each of them has some merit. Understanding exactly what you think "good medicine" is will help you find the right veterinarian.
I define good medicine as the course of action most likely to produce an acceptable outcome while remaining within the budget of the client I am dealing with. This means that I tend to treat each individual client's animals differently instead of sticking to a set of standards for all patients. In order to establish the most appropriate course of action I try to stick to medical information which has been scientifically validated. I also sometimes throw in the need for pain relief even when I know it is not essential to the long-term outcome.There are proponents of other definitions of good medicine. A number of my colleagues define good medicine as the course of action most likely to produce a diagnosis and cure or successful management of a case. This definition is a good one for situations in which there are no budgetary limitations. It gives a wide latitude for setting minimum standards of medical care which take into account situations that occur rarely but which might be prevented by the routine use of comprehensive screening procedures such as blood chemistry analysis and thoracic radiographs. This definition places the value of the patient's life above monetary concerns. Veterinarians tend to like this definition since following it is also healthy for the veterinarian's practice finances and because there is the least likelihood of a judgment error on the part of the veterinarian due to the use of a predefined "minimum database". Veterinarians following this standard often require a specific set of test procedures, such as a complete blood count, serum chemistry profile and urinalysis on all patients admitted for hospitalization or surgery. This is a good standard for people who desire to take the least possible health risk for their pets and do not consider the cost to be prohibitive.
Other people define good medicine as the least expensive set of procedures that produce an acceptable outcome in a predefined percentage of cases which constitute "acceptable risk". This places the value of monetary concerns above the value of the life of any particular individual patient but allows the delivery of more care to patients in general since monetary resources are not used up by a few patients. This definition tends to be popular among humane organizations who tend to think that more pets would benefit if medical costs were lowered overall. This reasoning might be more popular among vets if they didn't have to explain to the individual owners of the individual pets that die from "acceptable risks" what happened. For some reason, most people don't find any degree of risk chosen beforehand to be acceptable in retrospect when it is their pet that is harmed.
Some people think that good medicine is no medicine. This is a major theme of people who believe in "natural health" or who follow religions which blame disease on straying from God's path. Obviously, if this is the case then renewing one's faith is more important than finding an appropriate medication. Homeopathy, some aspects of chiropractery, some uses of acupuncture, some herbal treatments and other medical beliefs which have not yet been validated through scientific evaluation are compromises between no medicine and strict adherence to science-based medicine which appeal to many people. There are definitely veterinarians who have decided for one reason or another that scientific evaluation of medications is not all it is cracked up to be and who are among the believers in one or more faith based medical philosophies. I think that everyone involved should understand that the medical care delivered is based on a faith in the medical therapy rather than scientific validation. As long as this is the case it is clearly the choice of an individual in our society to pursue medical care that they are comfortable with.
There are people who seem to define good medicine for their pets as anything that makes them feel good, whether or not it really benefits their pet. I have actually had a client say to me "I just won't be able to deal with Buffy's death unless I have spent at least $175 dollars on his care." I am not making this up (except the name Buffy). Most clients don't know themselves well enough to be able to set an exact dollar figure on their guilt but they may be aware that they are at the veterinarian's out of a sense of guilt or that they are not necessarily concerned with the actual outcome of the pet's health crisis as long as they leave without a sense of personal responsibility for it. I can not begin to convey the sense of shock I felt when I finally realized that many of my clients did not really care if I provided the best possible care as long as I told them "you've done all you could do," and they believed it, no matter how far from the truth it might be. While I still have a difficult time reconciling myself to this particular attitude among my clients I have come to accept that it may be one way of coping with the real problem of not understanding how to evaluate the care provided by veterinarians.
Think about your definition for good medicine. It makes it much easier to find a vet who has the same definition! Just remember these things:
If you truly believe that your vet should take every possible precaution against a bad outcome and should be technologically progressive you shouldn't complain about cost.
If you really believe that medical care should be cost efficient then you have to accept some of the responsibility for bad outcomes when your pet happens to be the one in ten-thousand that does have inapparent liver failure or the 0.1% of pets who react badly to the least expensive medication.
If you don't think that science is a good way to assess the value of a medical treatment you have to accept that the next best way is trial and error utilizing your pet.
If you believe that the "good of the many" should outweigh the "good of the few" then you have to be willing to accept the death of any individual patient if it somehow contributes to the overall ability to deliver health care efficiently to the population as a whole.
If you are using medications based on personal faith in their actions then you are truly putting your faith on the line. It is very very hard to do this and remain non-prejudiced when rating the success or failure of the course of action you take.
There probably isn't one perfect definition for "good medicine". Don't be fooled by this label. Think about what you want for yourself and for your pets and do your best to find it.
Differential Diagnosis-
You may have heard your veterinarian say something about "the differentials"
when your pet was sick. This is a reference to one of the most important keys to making an accurate diagnosis. There are very few diseases with symptoms specific to that disease and no other. Such a symptom is termed "pathognomonic" because the symptom defines the disease. In all other diseases, the symptoms have to be considered as a group and weighed against each other to come up with a reasonable guess as to the cause of the illness.
A doctor's number one choice is his or her suspected diagnosis. All of the other diseases that might cause the group of signs seen in a patient are the "differential diagnoses" -- they are the second or third or fourth choices for the most probable cause of an illness, in your veterinarian's opinion. Your vet should then decide which diagnostic procedures are necessary in order to prove the diagnosis correct or to prove it wrong. In many cases it isn't even possible to come up with a single most probable cause for symptoms seen. In these cases all of the differential diagnoses must be considered and a diagnostic plan worked out to sort through them. Most veterinarians find diseases they are looking for much more readily than those they are not. Therefore, it is extremely important that all reasonable differential diagnoses be considered when a pet is ill. Your vet's ability to construct a differential diagnosis list may be the difference between finding an unusual cause for a pet's illness and death or disability for the pet.How do you know how good your vet is at this skill? It is probably not possible for many pet owners to evaluate a veterinarian's ability to build a list of possible differential diagnoses in many instances. Sometimes, though, it isn't too hard. Ask your vet what else might be wrong if you feel that treatment isn't going well. Ask what tests might help to distinguish between the other possible illnesses and the one that was diagnosed. If your vet won't discuss this issue or can't provide an alternative in most situations it should make you wary of the possibility that alternatives are not being considered.
How do differential diagnosis lists work to help your vet? Almost every symptom has several possible causes. Comparing the possible causes of each symptom present will usually lead to a short list of likely illnesses.
There is another way to create a list of possible differential diagnoses for a case that is equally as important and can often serve as a way to check to see how accurate the diagnosis made with the first method is. Once a vet is reasonably sure which disease is present, it is a very good idea to consider any disease which may look like this one as a differential diagnosis. The best way to do this is to check several reference texts to see which diseases the authors thought might be confused with the one your vet suspects is present. Most of the authors have been fooled once or twice by the diseases they list as alternative suspects so it is reasonable to assume that your vet will occasionally be fooled, too.
Consider an abbreviated example (not all differentials are listed for the
symptoms):In our example, we have a four year old female mixed breed dog with a productive and persistent cough, no fever and slight exercise intolerance. She weighs about 45 pounds, which is slightly overweight and she looks a little bit like a border collie.
There are many possible causes of coughing. They include heart failure, chronic bronchitis, parasite infections (heartworms, lungworms), pneumonia, tracheal collapse, a foreign body in the respiratory tract, and cancer.
Our patient's heart sounds normal, she is heartworm negative and x-rays do not show a foreign body, pneumonia or cancer. This leaves us with tracheal collapse, foreign bodies (not all of them show up on x-rays), and chronic bronchitis. Tracheal collapse usually occurs in small dogs. So at this point, we'd tend to look at chronic bronchitis as a likely problem. This leads us to the need to decide why this dog has chronic bronchitis. This can be caused by allergies (or at least appears to be -- proof is a little lacking), environmental irritants, parasites and for no known reason. Just because parasites show up on both our lists, we are extra cautious and test a second stool sample for lungworms, which do not always show up readily in stools of infected dogs. The sample is still negative. Our patient gets better on antibiotics after we talk the owner out of his brand new cigar smoking habit (just once I really would like to convince someone to give up smoking for the health of their pet).
If our patient hadn't gotten better we have a ready list of alternative suspects and we could plan a diagnostic process to eliminate other possible problems. I'd probably worry about inapparent heart disease as my next best choice but the important thing is to consider all the possibilities and keep working until a successful outcome is achieved.
It is usually easier for a client to look for a list of possible differentials based on a vet's initial diagnosis than to put together a differential list based on the presence and absence of various clinical signs. Experience really does make a huge difference in the ability to reduce a set of symptoms to a possible diagnosis. Research makes the difference when looking for alternatives to a diagnosis that has already been made. By examining references for differential lists it is usually possible for veterinary clients to find most of the other possible illnesses. Many times our clients have been able to help make a diagnosis once they knew more about the possibilities. After all, if no one thinks about the possibility of rat poisoning in a pet with a nosebleed, a client may not remember that the exterminator visited the week before.
I have not yet met a veterinarian whose first guess was always right. I did once have an employer who told me that all pets had to leave his hospital with a specific diagnosis. I asked him how I could give a specific diagnosis before having test results or response to therapy to aid in making the choice and he told me to make one up. "After all, if its wrong, you can just change it when the client comes back." Clients loved this vet. I can not tell you how often a client said to me "I just love Dr."X". He always knows exactly what is wrong with my pet! He must be brilliant," or some variation of that. He was a pretty smart marketer. But often, he was reluctant to change his diagnosis, even in the face of poor response to treatment or non-supportive lab work, because he had an emotional investment in it. You are much better off if your vet tells you that there are several possible problems, that treatment will be instituted for the most likely one and that diagnostic testing will be done to confirm the diagnosis, if confirmation seems necessary.
There is one special category of differential diagnoses that need to be discussed. In some instances there may be as many as three or four or more diseases that can cause the complete set of symptoms seen in a patient. In some of these cases the exact same treatment will work regardless of which of the many possible diseases is present. When I reach the point in the diagnostic process when I feel pretty strongly that I know all the remaining possibilities can be treated with the same exact treatment plan I often wonder if it is worth doing the lab work necessary to differentiate between them. Some vets feel very strongly that a diagnosis should always be confirmed, even in these cases. Others feel that it doesn't make a lot of difference whether a pet has disease A or disease B if the treatment is identical. I flip-flop between these positions based on the patient at hand. If I don't think there is much possibility of death or disability if I am wrong, I give treatment a chance to work without making a specific diagnosis. If I think that a pet is in serious trouble I tend to lean towards doing specific lab work, just to make sure I haven't missed the boat entirely in my diagnostic process. If I think the disease the pet has may have zoonotic potential (can infect humans) or if other pets in the household are at risk, that makes getting a more specific diagnosis necessary, too. In these situations it helps a lot to have a client who I can talk to reasonably about how much sense it makes to pursue an exact diagnosis.
If your veterinarian refuses to consider the differential diagnoses when treatment of an illness is not going well, you may need to consider asking for referral to an appropriate board certified specialist or consider getting a second opinion locally.
New MedicationsMoxidectin (ProHeart Rx) is a new "once-a-month" heartworm preventative that has recently been brought to market by Fort Dodge. Surprisingly little fanfare accompanied this medication and I have not seen any in-depth analysis of its strengths or weaknesses in comparison with the already available heartworm preventatives. It should work well based on its chemical class for the basic job of heartworm prevention. If there are significant differences between it and the other preventatives we'll provide more information as it becomes available.
There are a couple of new quinilone class antibiotics on the market. Orbifloxacin (Orbax Rx) and difloxacin hydrochloride (Dicural Rx) have recently been approved and compete for the market established by enroflaxacin (Baytri Rx). It is nice to have alternatives in this class, especially since both of these medications are approved for once daily use, but these do not appear to be significant advancements in antibiotic therapy at this time.
Old Medications revisited-
A new product for use in dogs with periodontal disease has been approved. It is doxycyline, a well known antibiotic, in a new formulation designed to be placed inside the pockets formed when periodontal disease weakens the attachment of the gums to the teeth. This product, the Heska Periodontal Disease Therapeutic appears to be a good way to ensure that antibiotic therapy reaches the areas that need it most after cleaning the teeth.
I am betting that the marketing department didn't have much influence over the name of this product, though.
Got a topic you want information on?
Right now we have a small number of subscribers. This gives us the luxury of asking you what topics you want covered with a very good chance that we can include them in a newsletter soon. Specific questions about treatment or diagnosis of an illness your pet is experiencing can be addressed to our e-mail address for subscribers (digest@vetinfo.com) and we will try to answer them as quickly as possible. If you have a general interest in a bigger topic, such as distemper virus or feline leukemia, let us know.
Also, you might have noticed that we have been changing the format each month to some degree. This is because neither Michal nor I are disciplined enough to stick to a set format. If there is some feature you really like that we seem to be leaving out of future issues consistently, let us know!
Not a Large Animal Story-
After the last few issues it is probably obvious to most of you that I spent a few years practicing on all sorts of creatures, big and small. Since our focus is now small animal and since I have told several large animal stories in a row, I decided to tell the story of one of my favorite canine patients this time.
Rusty's story starts out badly. He was a free spirit, a dog who had free run of the neighborhood and took advantage of it.
He was also an un-neutered male.
As usually happens, an intact male dog with time on his hands finds female companionship eventually. Rusty had the bad fortune of finding female companionship, along with at least three other male dogs, on a day when the female dog's owner had finally had enough of her male suitors. In fact, he or she must have had more than enough.
Rusty's owner arrived at the clinic unannounced and in a panic. "I think someone shot my dog!" It was a definite understatement. Rusty must have been really close when his assailant shot him with a shotgun. There was a three or four inch diameter entry wound. The shot had ended the likelihood that Rusty would seek female companionship in the future before entering the skin above his scrotum and there was a much larger wound on his right side where the pellets had exited in several sites. Rusty was pretty lucky to be alive, all things considered.
Rusty wasn't alone in his problems. Our hospital was becoming littered with male dogs, as further gunshot patients arrived. We assume that they all arrived from one site, based on where they lived. If so, the person shooting at them was pretty good at it. Rusty was the most damaged of the four dogs who eventually came in with gunshot wounds that day but we did have a long day repairing everyone.
We administered blood to Rusty, cleansed his wounds as best we could and determined that we could not close the series of exit wounds because there wasn't enough of the muscle wall left to do that. In an unbelievable stroke of luck, there was almost no significant internal damage. We just kept him bandaged and waited for his side to heal. He stayed in the hospital for a couple of weeks until he finally healed enough to go home. When we decided to send him home, he still had a large wound on the side with no skin over it, just a pink bed of scar tissue that would take another month to heal completely.
Rusty left our hospital about 10 AM.
About 4 PM that same afternoon, we had another dog arrive with a panicked owner. "Look at the wound on Dusty's side! He's been gone for about two weeks and he came home with this terrible wound." My receptionist was a little dumfounded. Here was Rusty, back at our hospital with a new owner. She had no idea what to do, so she just sent him back into the exam room for a checkup with me.
After listening to the story of how Dusty was gone for two weeks and came home with a terrible wound, I knew I had to say something. What came out was " Well, someone else just paid me $800 because we worked on his dog Rusty for two weeks here at the hospital and this is the same dog." It wasn't very clever but it did sum up the situation.
"Well, Doc, for $800 I think this must be HIS dog!" Our worries over a major conflict between the dog's owners were dissolved pretty quickly by this statement.
We were overcome with curiosity and checked out both "Rusty's" and "Dusty's" records. These are the real names that the "two" dogs had. We had been vaccinating him twice a year, he was getting heartworm medication at two homes and both owners were really sure that he was their dog.
As it turns out, Rusty and Dusty lived about a fourth of a mile apart. Rusty's owner worked the day shift and Dusty's owner worked the night shift. Both owners had Rusty's full attention during the times they were home, for the most part. Since both owners allowed him to run free it was never apparent that he had two homes. His names were so similar that he probably never even noticed they were different.
Although both parties agreed that he was now Rusty and that he was going to be the responsibility of the owners that paid the bill, he was lucky one more time. His night shift owner was being transferred to another state and had been looking for a new home for Rusty. If he had been successful, Rusty may have lost out on his other home, without anyone realizing the loss had occurred..
Rusty did settle down after his shotgun neuter. He recovered fully from his wounds and pretty much stayed in his own yard for the next ten years. He never complained while we were treating him and he never got cross in his old age, either. Rusty recently passed away and we miss him.
We appreciate your support for our website and for the VetInfo Digest. We are working to find a sponsor for our site and hope to be able to keep the website free to the public through sponsorship and newsletter sales. If that doesn't work we may go to a subscription basis for both the website and the newsletter. Your payment will cover both subscriptions if this happens. In the meantime, subscription sales have helped us continue to operate a website which now generates over 500,000 hits per month! Thank You Copyright, TierCom, Inc., 1998 Tiercom, Inc. P.O. Box 476 Cobbs Creek, VA 23035 The opinions expressed in this newsletter are solely those of the author, Michael Richards, DVM
This page was last edited 06/15/04
Subscriber homepage |Backissues | Breed index |digestindex |Vetinfo | vetinfo4cats| vetinfo4dogs
Canine Encyclopedia | Feline Encyclopedia| VetInfo Digest |Links |Zoonotic info
Please do not send anything in attachment form. We will not be able to open it due to security risks.
This page is authored by
Dr Michael Richards, DVM
and produced by TierCom, Inc.
Opinions expressed are those of Dr. Richards.
Designed and edited by Michal Justis
©1996,1997,1998,1999,2000,2001,2002,2003,2004 TierCom, Inc