VetInfo Digest October 1998
Euthanasia
Leptospirosis
Fall Things -- when to stop flea prevention, when to stop HW meds, etc.
Murder, She Thought
Contacting Us
Euthanasia
Many of my clients have questions about euthanasia. When is it right? How does it work? Do I have to be there when my pet is "put to sleep?" Who takes care of burial or cremation? What can go wrong? Can my vet give me something that will allow me to cause my pet’s death at home in a humane manner? Will my vet come to my house to euthanize my pet? Being prepared for the time when euthanasia seems necessary might make it a little easier to handle.
Almost all veterinarians in the United States use euthanasia solutions composed of a barbituate in concentrated solution. Some of these solutions contain only phenobarbital (Sleepaway Rx, others) and others contain phenobarbital in combination with another agent (Beuthanasia Rx and others). I have tried two of the solutions and I prefer the pentobarbital alone. Many vets use the combination solutions in order to lessen the paperwork burden associated with controlled substances, though. Sleepaway is a Schedule II drug and is more tightly regulated than Beuthanasia, with is a Schedule III drug. There have been euthanasia solutions consisting of other medications in the past, such as T-61 (TM) but these are no longer used in the U.S.
Pentobarbital was used as an anesthetic agent prior to the availability of safer medications. Its major drawback was a tendency to cause unexpected death during anesthesia so its usefulness as a euthanasia solution is unhindered by this effect. It is a very effective anesthetic agent and it is reasonable to assume that there is no conscious pain or discomfort associated with its use, other than that which occurs during the placement of the needle or catheter in the vein to administer the solution. It causes death by causing depressing the respiratory control centers in the brain sufficiently enough to stop respiration entirely. It may take several minutes for the heart to stop beating after administration of this agent in some dogs but they are not conscious during this time. Pentobarbital does also have direct depressant effects on heart muscle but some dogs do seem to be resistant to this. It is not highly unusual for a dog to sigh or to make other audible noises once or twice shortly after the injection of pentobarbital or combination agents. This effect can be subdued by administration of a sedative prior to the use of pentobarbital but this is not always possible and sedatives can lower blood pressure making it harder to find a vein. It is also not unusual for a pet to twitch or even move slightly for a few moments after the injection of a euthanasia solution. It is necessary for pentobarbital to be administered in a vein or directly into the heart for it to work rapidly. In some cases this is not possible and it can be administered by needle into the abdominal cavity. It takes much longer to work when administered in this manner but there are times when it is better to make one injection into the abdomen rather than repeated attempts to find a vein in a dog with circulatory collapse. Most dogs and cats in which the solution is administered into the abdomen (intra-peritoneal injection) fall asleep long before the respiratory depressant effect occurs.
There are a lot of different methods of handling the euthanasia process. Some veterinary hospitals place a catheter into a vein to make further injections easy to accomplish and then administer a sedative. Once the pet is sleepy they go ahead and administer the euthanasia solution. Other hospitals administer the euthanasia solution directly, utilizing a catheter or hypodermic needle directly. This takes less time, which can be very important to some pet owners but there is more chance that the pet may struggle at the moment of euthanasia against the insertion of the needle or catheter. It is hard to figure out which way is best and we will use whichever method seems most likely to proceed smoothly for a particular pet and its owner. If you have a preference it is best to discuss it prior to the office visit or house call with your vet. Euthanasia is a very difficult decision for many pet owners and most veterinarians want to make sure that the owner is not upset even more by the process, so most veterinarians will adjust their procedures to accommodate reasonable requests.
Many clients and people who have written to me ask if it is possible for veterinarians to dispense a pill or other medication for use at home by the owner to cause death in a humane manner. I do not know of an effective and painless method of causing death with medications, other than injectable pentobarbital in pets. I do not anticipate that a product that can induce death in a manner that is compatible with humane euthanasia will ever be available from veterinarians. Such a product would almost certainly cause death in humans as well as their pets. It would not be possible to prevent the euthanasia drug from being used inappropriately, such as to murder a spouse. The potential for accidental or purposeful misuse of a medication that could cause quick and painless death would be too great. All of the common toxins that I can think of have pretty bad side effects. They are not the way that I would choose to die. It is unfortunate, but we are stuck with the current medications for euthanasia and they are controlled substances that must be administered intravenously under the supervision of a licensed veterinarian.
There are some things that you can do to make sure that the process of euthanasia is as comfortable as possible for your pet and for your family. It is necessary for your vet to ask if your pet has bitten anyone within the last ten days. Many times when a severe injury to a human has occurred the owners will request euthanasia. If a pet has bitten anyone within the last ten days prior to the office visit for euthanasia, it is necessary to consider testing for rabies. Most public health agencies do not wish to pay for rabies testing when it is less expensive to observe the pet for ten days, which effectively eliminates the possibility that rabies could have been transmitted during the biting incident. When waiting and observing the pet is not possible the public health agency will usually require rabies testing of the pet, which involves submitting brain tissue for examination by a pathologist. It is very important to let your vet know if someone was bitten, even inadvertently, by your pet so that appropriate measures can be taken to insure the safety of the individual bitten. So be prepared for this and try to understand the necessity for being cautious if your pet has bitten someone. The vet may also want you to sign a form stating that you understand that the service being preformed will cause your pet to die. There have been several lawsuits over this issue, including at least one in which the owner was dropping a dog off for surgery and the words "put the pet to sleep" made perfect sense in that context --- but resulted in a tragic situation. Forms are difficult to go through when you are grieving over the impending loss of your pet but if they are part of the process and you should expect to deal with them. Once these legal issues are out of the way there are some important decisions to make about your comfort and your pet’s comfort.
I firmly believe that most pets are more comfortable with their owners present. There are a few pets that are protective of their owners and are more likely to be calm when their owner is not present, though. You should think about your pet and its previous vet visits and decide whether or not to be present when your vet administers euthanasia. If your pet is going to be calmer and more content because you are present you still have to decide if you can handle the situation. Your vet is going to be making an injection into a vein in a pet that is often not going to have good circulation or may even have problems like swelling in the extremities that makes administering solutions intravenously very difficult. Sometimes it is possible to let your vet place an intravenous catheter while you aren’t present and then to come into the room when the final injection is made into the catheter. Other times it really is better just to be there the whole time. It is your choice, though. If you do not wish to be present when your pet is euthanized just say so. Most veterinarians probably prefer that the owner not be present and this would be a relief for them, too. Even though I really think that it is better in most cases for the pet if its owner can be with it I understand why many people do not wish to be present. We will still try to comfort a pet and I’m sure most veterinarians do, too.
We will travel to the client’s home if they feel that they or their pet would be more comfortable if euthanasia is performed there. For most pets this probably isn’t really necessary. Most pets have been to the vet’s and are not bothered much by the trip there. Having the whole support staff of the hospital or office present is helpful. But a few pets are much more content at home. Once in a while an older large breed dog that can’t walk almost has to be euthanized at its home. If your vet can’t provide this service there may be a house call practice in your area which is better equipped to help.
Try to remember that your vet is human at these times. Euthanasia is pretty stressful for veterinarians, too. If there is a struggle to find a vein it takes a great deal of effort for the pet owner not to get upset, but getting upset makes the situation worse. Try hard to let your vet work without asking questions such as "isn’t there any way to make this go faster?". Almost always the answer to that question is that the best and fastest way to get through the situation is to let your vet work with as little additional pressure as possible. In most cases euthanasia will go better than you imagine it will.
I am grateful that we have the option to euthanize our patients when the need to alleviate suffering is clear. It would be very difficult to watch patients I care for suffer needlessly. I do have some clients who do not believe in euthanasia under any circumstances. When we are faced with a pet whose pain or suffering is intense and a client who is unwilling to consider euthanasia as an option we do our best to compromise with the client and provide good pain relief and good supportive care. All of us have to do what we feel is right in difficult times and I can’t say that people who chose not to consider euthanasia are wrong. I am just glad that the option exists when it seems like the right thing to do.
Leptospirosis
Leptospirosis is a hot topic at dog shows and other competitions now. There has been an epidemic of leptospirosis in Long Island, NY now for a couple of years. It seems like there is an upward trend in the number of diagnosed cases across the country, although that isn’t certain since no one really keeps statistics on the number of cases of diseases in dogs and cats. This has occurred concurrently with recognition among veterinarians that leptospirosis is the portion of the combined canine vaccines that is most likely to cause reactions. So many vets are not vaccinating for this disease. That sounds pretty bad but the new cases of leptospirosis being reported are from Leptospirosis species that the vaccines do not protect against. At present there is no vaccine for the two strains causing most of the current problems, L. grippotyhosa and L. pomona. A third type (serovar) of Leptospira, L. bratislava is reported to be on the rise as well.
Leptospirosis is a water-borne bacteria. It is spread most commonly by contamination of water sources by infected urine of wildlife and domestic animals. It can live in the environment long enough to spread effectively. Leptospirosis is most commonly associated with kidney disease but some of the strains of the organism can cause liver damage, induce bleeding disorders, cause neurologic signs or uveitis (eye inflammation).
Leptospirosis is difficult to diagnose with certainty because the organism doesn’t grow well in cultures. Serum titers are useful in making a diagnosis but it often takes paired samples to demonstrate a rise in titer. In the meantime, it is important to treat for the organism to try to limit the damage that it does. Leptospirosis organisms are susceptible to penicillins, which should be used for at least two weeks if infection is suspected. It is also important to treat for any damage that is occurring to organs and to control any developing bleeding disorders. Kidney damage and bleeding disorders often require very aggressive treatment in order to achieve a successful outcome so this is a situation in which long-term hospitalization may be appropriate and necessary.
Leptospirosis is especially scary because the bacteria can infect humans. It is important to observe good rules of hygiene, such as hand washing after handling the pet and even wearing latex or vinyl gloves when cleaning up urine or other body fluids. Pets suspected of having this illness should be quarantined from contact with other pets or any household members incapable of maintaining good hygienic practices.
People who own pets that congregate in spots such as parks, dog shows, sporting competitions and other events should be careful about exposing their pets to places where water may be contaminated with urine or where there may be enough urine contamination to pose a risk. This can be very difficult to manage. It would be nice if there were an effective vaccine for the current crop of leptospirosis infections but there is not. If the older strains of this disease begin to reappear as vaccinations are no longer given it may be necessary to reconsider the risk/benefit ratio of those vaccines as well.
It is very likely that one of the vaccine manufacturers is working on a new leptospirosis vaccination but I have no way of knowing whether that is the case. It would be worthwhile to check with your vet occasionally to see if there is a vaccination available if your pet fits the "high risk" profile of a dog or cat that is exposed to potentially contaminated water sources or is frequently in contact with large numbers of pets from all over the country.
All in all, leptospirosis is still pretty rare. It is still a good idea to consider it whenever kidney disease occurs in a young to middle aged pet or when uveitis (ocular inflammation) occurs for no known reason.
Fall Things -- when to stop flea prevention, when to stop HW meds, etc.
This is the time of year when clients want to know when to stop using the monthly flea medications and when to stop giving heartworm pills for the winter. It is a time when it is a good idea to make sure that an outdoor pet has adequate shelter for the winter and to remember to increase the amount of food for outdoor pets as the weather gets colder, since they will use more energy to stay warm. Hunting dogs may need to start on a physical fitness program to be ready to hunt in the late fall or early winter.
The good news about fall is that the flea season will be over soon in many areas of the country. The bad news is that the whole crop of this year’s fleas is reaching its peak and if you haven’t been controlling their population you may be over run by them. The best advice I know for when to stop flea prevention medications is to stop when the weather has been consistently below 70 degrees Fahrenheit for a month or so. In some areas of the country this means you can’t ever stop trying to control fleas. In other areas of the country it is getting close to the end of the flea season.
Heartworm medication should be given from the time mosquitoes appear to two months after the weather in your area is consistently below 70 degree Fahrenheit (many bugs have a hard time with temperatures that are cooler than this and mosquitoes, which carry the heartworm larvae, are no exception). It is necessary to give the medication for two months after the mosquito season stops because the medications kill the heartworm larvae better are certain stages than at other stages and it is necessary to wait the sixty days to make sure that all of the susceptible stages of larvae are killed. In Virginia it is probably OK to skip heartworm prevention medications in January, February and March. April and May can even be OK in parts of the state. Many vets think it is better to give the medications all year since they also prevent roundworms and hookworms which are more likely to be all year problems. In addition, some people don’t start the medications again if they skip a few months and it is critical to give heartworm preventatives when their are mosquitoes around to carry the infective larvae.
If your pet is on prednisone for allergies it may be possible to taper off the medication in the fall and discontinue it in the winter. Ask your vet about the best way to taper off the prednisone dosage before stopping it and keep in contact with your vet if tapering off the dose doesn’t work because your pet is still itchy or if there are any problems during the withdrawal process.
Tests your vet runs over and over again
There are two tests in veterinary medicine that are often run over and over again. Many times pet owners are frustrated by the prospect of paying for these tests. Why do vets do it?
Heartworm tests are repeated at various intervals, depending on where a pet lives, how the heartworm medications are administered, what the package insert for the heartworm medication says and on the veterinarian’s personal opinion about how frequently the test is necessary.
In our practice we test for heartworms the first time when a pet is over seven months of age and then again every two years if the pet is on monthly heartworm preventative medications. This is in accordance with the package insert recommendations and is frequent enough that a developing case of heartworms would be picked up in time to treat it without much complication. The package insert for daily heartworm preventatives calls for yearly heartworm examination and for testing anytime that there has been a break in administering the medications since diethylcarbamazine can cause severe side effects in a pet harboring heartworm microfilaria. I can understand veterinarians who test yearly for heartworms in all cases even though I am comfortable with a longer interval. I can not think of a good reason to test more frequently than once a year. Even if you give the medication just as directed and never skip a pill it is necessary for your vet to check your dog for heartworms at least once every two to three years in order to fulfill the basic doctor/patient relationship required for dispensing prescription medications. Once in a while, even with the new monthly pills, a dog comes up positive unexpectedly. It is a good idea to recheck the results with a different test when a dog on heartworm preventative medications shows up positive. The tests do sometimes have false positive results. It adds yet another test but the bottom line is that your vet wants to do what is best for your pet and this is a time when multiple testing and when retesting often makes sense.
Feline leukemia testing is also suggested over and over again in some cases. The problem with feline leukemia virus is that it can remain hidden in the body for long periods of time, literally years, then reemerge to cause disease. So a cat that has an illness for which no other explanation is immediately obvious should probably be tested for feline leukemia. How many times is enough? I honestly have no answer for that question. I have tested cats six or seven times during their lifetime. I thought that these tests were necessary because there were enough clinical signs that I just couldn’t be sure that feline leukemia was not present. My best advice on this test is to allow it when your cat is ill because there just isn’t any way to be sure that feline leukemia is not the current problem even if there have been multiple tests for it in the past. If you have to chose between the feline leukemia test and other testing in order to conserve money the choice may be harder. If there is a recent test for feline leukemia it may be best to pursue the other testing options if there is not enough available money for both tests. Rely on your vet to let you know which test he or she thinks is most important in that case.
Murder, She Thought
My receptionist, Barbara, came into the exam room and interrupted my examination of a pet. It was highly unusual for Barbara to do this and usually it meant that there was an emergency or a long-distance phone call that couldn’t be put off.
"I’m sorry to interrupt, but there is someone on the phone who seems to be whispering and I can’t understand them. What do you want me to do?", Barbara said.
Intrigued, I excused myself and went to answer the phone.
"Dr. Richards, is that you?" a very quiet voice on the other end of the phone inquired.
"Yes it is, can you please talk louder, I can’t hear you very well," I answered.
"No, I can’t. My husband is in the other room and I don’t want him to hear what I’m saying, just in case. I don’t want to go to jail and I don’t know if I’ve killed him, " said the voice, now an agitated whisper, almost clearly audible at the end.
"Is this Mrs. Banks?", I asked. I can often recognize distinctive voices on the phone. Mrs. Banks was about 90 years old and had a pretty distinct Yankee accent, despite having lived in Virginia for the last forty years or so.
"Yes it is doctor. Please don’t say that so loud!", replied Mrs. Banks, now talking fairly loudly herself. "I think I killed Ben. He’s not dead yet or anything but I have to know right now if he’s going to die. You see, I don’t see so good anymore and I keep the dog’s heartworm pills in the kitchen cabinet right next to Ben’s vitamins. I just got to the end of the bottle of vitamins and I read the label and it is Prissy’s heartworm pills. I am sure I’ve been giving him his vitamins out of this same bottle for the last year!"
I had pulled up Prissy’s record on the computer monitor by the phone and was reading it as Mrs. Banks had slowly and quietly told her story. I had just figured out that she had purchased a bottle of 400 heartworm pills a little more than a year ago and that it was entirely possible that her account of the situation was accurate.
"So is Ben going to die, Doctor? Do you think that the sheriff will think it was murder? What am I going to do?" By now I was pretty sure that anyone but Ben or another nearly completely deaf person would have heard Mrs. Banks. She was getting very loud.
"No, Mrs. Banks, Ben is not going to die. In fact, he is safe to travel to the tropics if he wants to. You see, diethylcarbamazine was originally developed to prevent elephantiasis in humans and it is still approved for that use. The dose is about the same as for heartworms but Ben is a lot bigger than Prissy so I’m sure that he hasn’t been overdosed." I could hear a loud thump as Mrs. Banks either fell or sat down hard. I asked if she was all right.
"I’ve never been more relieved, Doctor. Are you sure you’re right about this?".
"Well, I’m sure that Ben will be OK, Mrs. Banks. After all, you’ve been giving him the medication now for over a year and he’s still OK, right?" Then a bad thought crossed my mind. "But you have to bring Prissy in for an examination as soon as you can. She’s missed a whole year of heartworm prevention."
"Do you think she’ll be OK, Doctor? I just couldn’t stand it if I did anything to harm Prissy," Mrs. Banks said, getting herself worked up again.
I couldn’t imagine a pet in my practice who would be less likely to have heartworms just because it wasn’t on heartworm preventative medications. Prissy’s lifestyle consisted of long naps indoors between short episodes of riding in the car to the bank or the post office or other daily errands. While her owners were still pretty active people they weren’t out too much after dark, having long ago given up driving at night. Mosquito bites were probably a rare event in Prissy’s life.
"I think she’ll be OK, but we really do need to check her out," I said.
The next morning Prissy was in our office and we drew blood to check for the presence of heartworms. Fortunately, she didn’t have them. Ben Banks didn’t, either. And he did live on for several more years, unaffected by his year of daily heartworm pills.
Contacting Us
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Thanks! 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, unless otherwise noted in the text. Michal Justis is our web designer and graphic artist. This page was last edited 06/21/04
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