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VetInfo Digest June 2005

Table of Contents:

Desperation Medicine:

Skin disease

"Ain't Doing Right"

Chronic diarrhea

Amputation

Persistent upper respiratory infections in cats

Chronic gum disease in cats

Flea infestations

Persistent abscesses

Chronic arthritis

Spinal damage

Brain damage

Chronic ear infections

Enucleation of eyes

Pain relief

True desperation!

New Stuff and Brief Notes

This Month's Note:

There is a great deal of information available in the online subscriber area of our web site that is not in the general information section. If you have a particular area of interest you might find that we have covered your topic in some depth in a past issue of the VetInfo Digest.

Michal is working to produce a table of contents similar to the one on the general web site and there are brief summaries of what each issue of the VetInfo Digest covered in the back issue directories.

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There are times when following normal medical guidelines or restricting treatment to approved and proven therapies is simply not working for a patient. In other instances there simply are no really good options for treatment of a pet' condition. In these situations it is sometimes necessary to simply throw away the rule books and take some chances in order to try to help the patient. I call this " medicine" but it tends to show up in textbooks and articles under various other names, such as salvage medicine or palliative treatment.

I don' know any veterinarian, no matter how scientific their overall approach to medicine is, who do not occasionally resort to treatments that have no real scientific basis. Sometimes these are treatments that simply sound logical and other times they are treatments that a trusted colleague swears will work for some pets. In any case, it is tough to be too judgmental when desperate clients seek desperate measures in an effort to save their pet while knowing that once in a while I have been willing to step outside the bounds of science and logic myself.

I thought that this month I would provide my view of desperation medicine and which things seem to have worked in our practice at times.

Skin Disease

Every now and then we have a pet come into the practice with itchiness that is so extreme the pet is at risk of injuring itself by scratching or chewing excessively. Most of the time it is possible to find a cause for this kind of itchiness but sometimes all the diagnostic tests come up empty and we have to take a trial and error approach to treating the pet. These are the things that I think are worth trying in these situations, even when there is no diagnostic evidence to support doing so:

1) I think that it is worthwhile to treat dogs with extreme itchiness for sarcoptic mange, even if no evidence of the parasite can be found. I think it is worthwhile to treat cats for demodectic mange under the same circumstances. These mites can be hard to find even with good skin scraping techniques. We generally use ivermectin for both of these conditions. The dosages we use do cause side effects in some pets and this isn' risk free. Most of the time this doesn' help things but it helps often enough to make it good desperation medicine.

2) It can be very difficult to tell if a pet has a yeast infection, especially when there are multiple problems occurring at the same time. When we see thickened, scaly or greasy skin and the pet is very itchy and not responding to treatment for more common problems like bacterial skin infection or allergy, we sometimes just treat for a yeast infection to see if it helps. We use ketaconazole for this. Like many of our desperation measures ketaconazole isn' completely safe. It can cause liver damage and seems to cause vomiting more than most medications. It generally takes 30 days of ketaconazole to cure a dog who has Malassezia skin infections. Even though side effects have to be considered we have not actually seen much problem with them in our practice so we think that this is a reasonable desperation measure.

3) Sometimes we see dogs who chew on or lick their feet incessantly with little or no sign of skin disease there or anywhere else. Most of these dogs have allergies but some do not respond well to medications for allergic skin disease. These dogs also sometimes have Malassezia yeast infections and once in a while ketaconazole administration will stop this behavior. It is usually necessary to treat for at least a month before it is possible to tell for sure if the medication is helping. There should at least be some improvement within a month if ketaconazole is going to help. Unlike the general skin it can take longer to completely clear up nail bed infections but it usually doesn' take a year or so, as is often the case in people.

There are times when skin disease seems to get out of control despite the use of medications that seem appropriate based on our diagnostic tests and experience. Once in a while when we really feel that the response to treatment just isn' adequate we stop all the medications and start the entire diagnostic and treatment process over again. This can be a drastic step for a pet owner to take who has a dog or cat with severe skin disease but sometimes we find we have created a drug reaction, masked an initial symptom or that a new disorder has occurred that we couldn' diagnose without rechecking the testing.

Flea Infestations

We have a few families who seem completely unable to get flea infestations under control, despite following our standard recommendations to treat the pet with imidocloprid (Advantage tm), fipronil (Frontline Topspot tm), selamectin ( Revolution Rx) or lufenuron/nitenpyram (Program Rx, Capstar Rx) and treating the pet' environment with a flea control product that kills adult fleas and pre-adult fleas.

We think that some of these people have problems because they don' follow the directions for applying the flea control products or because they don' treat all the pets in a household. It is hard to explain why people do this, but we have a fair number of clients who treat one pet in the household for fleas and not the others or who treat all the pets in the household except for one or two. The reasoning behind treating all the pets except for one or two is usually that one of the pets is older or is sensitive to flea control medications. It is imperative to treat all the pets in the household if you have a persistent flea problem. Anything short of this will often lead to failure of flea control measures.

Some of our clients who have persistent flea control problems do seem to be doing everything right. For these people, we have to pull out all the stops and consider more drastic measures. It is technically illegal to use an EPA regulated product in a manner inconsistent with its labeling but we know that even the really good " a month" flea products really only last about 3 weeks. So we hint that it might be better to apply them every 3 weeks if there is a problem controlling fleas. This sometimes works. It can also be helpful to use one of the monthly flea products in combination with nitenpyram (Capstar (tm) tablets) or with a pyrethrin based spray. When we do this we usually use the monthly product according to directions and then add nitenpyram and use it once or twice a week. This combination has worked for some of our clients when nothing else seemed to be helping.

When clients become very desperate to control fleas in the house and don' mind using a powder that stays in the carpeting the use of borate salt flea control products can be helpful. Flea Busters (tm) and Flea Stopper (tm) are brand names of two of these products.

Persistent abscesses

We sometimes see cats who have persistent abscesses that either don' respond at all to the common antibiotics or respond poorly and recur when antibiotics are stopped. If we treat with two of the antibiotics that usually work for abscesses and they continue to recur, we often try a round of doxycycline. We do this on the suspicion that a particular type of bacterial infection, referred to as an l-form infection, is occurring. Doxycycline is generally not a good choice for use when an abscess is present but it is often the only antibiotic that will work for l-form infections. These bacteria don' grow on standard cultures so there really isn' any good way to rule them out other than to try treating for them.

In both dogs and cats it is also worthwhile to do an exploratory surgery to determine if there is a foreign body, such as a thorn or foxtail awn causing persistent abscesses. We have a collection of strange things we have taken from persistent abscesses, including a fiberglass shard, pieces of wood, canine teeth, a blow gun dart and several pieces of gravel. It may seem extreme to do surgery that sometimes gets to be quite extensive just to rule out the possibility of a foreign body in an abscess but it can be beneficial at times.

Chronic arthritis

Arthritis that is interfering severely with the quality of life for a pet can be a problem even though we have very effective arthritis control medications available. The newer non-steroidal anti-inflammatory (NSAID) medications such as carprofen (Rimadyl Rx) or deracoxib (Deramaxx Rx) work very well for arthritis in dogs but there are times when they are not good enough. Adding a narcotic agent such as hydrocodone or even morphine can be very helpful. The combination of a narcotic and a non-steroidal anti-inflammatory medication has been demonstrated to have an additive effect that works better than either product alone.

In older pets, when it seems likely that without relief from the arthritis pain euthanasia may be necessary, it is reasonable to use corticosteroids for arthritis. Under ordinary circumstances this is a poor choice for arthritis because of the potential for side effects but when the other choice is euthanasia, there really isn' any reason to worry about whether the side effects will be a problem.

Weight loss has been shown in several studies to be as beneficial as treatment with NSAIDS for relief of arthritis pain in overweight pets. If you can' bring yourself to diet your dog sufficiently to bring about weight loss consider boarding them and giving the kennel the weight loss directions for feeding that your vet provides. Most kennels will follow feeding directions for pets in their care. Cats do not tolerate calorie restriction as well as dogs do so it would be necessary to involve your vet in the loop if you had to consider boarding or hospitalization to obtain weight loss. As long as a reasonable diet plan is followed it is possible for most dogs and cats to lose weight with calorie restriction alone -- make sure your vet approves any weight loss plan for your cat, though.

Many of my clients resist using mechanical assistance for their pets with arthritis or conditions causing weakness. There seems to be a general idea that dogs and cats won' like to use a wheeled cart or will resist assistance with a sling or other device. Our experience has been very different from this. Almost all of the pets in our practice (we can remember one exception) took less than a week to become comfortable with their "" and to return to near normal activity levels -- or in some cases increased activity levels. Don' rule out the possibility of aiding your older pet by providing it with a set of wheels to help with mobility.

Neurologic Damage in the Spinal column

Damage to the nervous system through injuries such as a herniated disc can cause paralysis and inability to regulate urination. Due to the cost of spinal surgery it is not uncommon for us to have to try to treat these symptoms medically. The administration of methylprednisolone (Solu-Medrol Rx), especially if this can be done within a few hours of the injury, can be helpful in limiting damage to the spinal cord. This can make a big difference if treatment manages to preserve the ability to control urination or provides some mobility where there otherwise would have been none.

This is another place where people shouldn' discount the use of wheeled carts to provide pets with mobility despite the presence of serious injury.

Neurologic Signs that seem to be due to brain disease

It can be very difficult to pinpoint the cause of symptoms that appear to indicate a brain injury. There are many areas of the world in which it is difficult to arrange advanced imaging studies, such as an MRI or CT scan to aid in the process of diagnosing brain injuries. Regular X-rays are very rarely useful, although it is possible sometimes to discern skull fractures or other disorders affecting the bones of the skull. Ultrasound examination just isn' helpful in aiding the diagnostic process for the majority of brain injuries. Therefore, it is often necessary to carefully document the neurologic deficiencies present and then to make a best guess as to the probable cause. This leaves a lot of room for error. While veterinarians almost always prefer to make a solid diagnosis first and then to determine the appropriate treatment, this isn' always possible with brain injuries. For this reason, it is not uncommon for veterinarians to try several medications that might help when a brain injury is present, in the hopes that one of them will be helpful.

When neurologic disease is present in a cat and it isn' possible to make a definite diagnosis we almost always try using clindamycin, an antibiotic that works for toxoplasmosis, a parasitic illness that can cause neurologic signs. For both dogs and cats with unexplained nervous system disease that seems to be originating in the brain we usually try furosemide or prednisone to try to reduce fluid pressures in the brain to see if that helps. These are treatments that rarely cause complications and sometimes provide visible benefits. There often isn' a solid rationale for using the medications but this is another of those situations where desperate measures may be necessary.

The "' Doing Right" Pet

There are times when a pet owner knows that his or her pet is not doing well but we are not able to make a definitive diagnosis. This can happen when there are few clinical signs of illness or when it is obvious that a pet is ill but testing just doesn' reveal a cause. In these cases it makes sense to me to try a trial dosing period with doxycycline to try to rule out vector borne diseases such as ehrlichiosis, Lyme disease and others that are sometimes just hard to diagnose with certainty. Doxycycline is reasonably safe but it does have one drawback that has to be considered, which is that it can cause severe esophageal inflammation and even esophageal strictures if it is given in capsule or tablet form and the pill or capsule hangs up in the esophagus while being swallowed. It is always a good idea to give some water orally or to feed a small amount of food after administration of doxycycline in tablet or capsule form. This is especially important in cats.

We sometimes have pets who respond really well to intravenous or subcutaneous fluid therapy even though we can' find much wrong with them on a physical exam or through lab work. This is another one of those things that almost never hurts, might not help but is worth trying when the situation is desperate.

I know that the indiscriminant use of antibiotics can be a problem but there is a place for using a broad spectrum antibiotic for a reasonable trial period to see if it will be helpful. Most antibiotic resistance seems to be associated with the use of inappropriate (usually low) dosages and inappropriate dosing periods (less than 3 to 5 days). When we use antibiotics as a desperate measure we try to emphasize the importance of giving the medication as directed and if that is done they are reasonable to use even when there isn' an absolutely clear indication of need.

Chronic Diarrhea

Chronic diarrhea is an enormously frustrating problem fairly frequently in cats and to a lesser extent in dogs. There are a number of tests that can be run to try to pinpoint the cause of the diarrhea but it is often impossible for a pet owner to consider all of the possible test procedures due to cost constraints or cooperativeness of the patient. When chronic diarrhea goes on and on without much response to treatment or without a definite diagnosis it is worth considering supplementing cobalamin (Vitamin B 12). There is pretty good evidence that cobalamin deficiency keeps some cases of diarrhea going on and on over time when the original disease that lead to the diarrhea and to the cobalamin deficiency is long gone. When cobalamin depletion occurs due to chronic diarrhea it is necessary to use injectable cobalamin to provide supplementation. Orally administered cobalamin may not be properly absorbed in a patient with diarrhea.

No matter how many fecal examinations fail to show worms or other parasites it is worth trying a broad spectrum deworming agent, such as fenbendazole (Panacur Rx) at least once when dealing with chronic diarrhea. We look for worm eggs on fecal examinations and some worms shed the eggs intermittently, making it possible to miss them even with several fecal examinations. It can also be hard to find giardia parasites even when they are causing problems and fenbendazole will also kill giardia. This works often enough that some of the experts in the field of gastrointestinal disease refer to " deficiency" as a disease syndrome and they are only being partially facetious.

We often try dietary changes when diarrhea is present. A fairly recent study of dietary changes for diarrhea showed that about 25% of dogs and cats will respond to dietary changes regardless of the type of new diet chosen. While we favor low fat diets in patients with diarrhea it is also reasonable to consider high fiber diets, diets that are highly digestible, diets enriched with omega fatty acids (usually from marine fish oil) and diets that are made to be hypoallergenic or that consist of food sources the dog or cat has not been exposed to before. With all of these choices it is possible to try several diets without success but often one of these dietary choices will help a patient. Our thinking is that you might as well try them all, for reasonable intervals, when chronic diarrhea isn' responding to other therapies.

When to consider amputations

Amputation of a limb is something that most pet owners are very squeamish about. This can be a real problem in some situations, since amputation is the best course of action for several conditions affecting dogs and cats and often provides them with a great deal of relief.

Probably the most important time to consider amputation is when a dog or cat has bone cancer affecting one limb. There isn' a big chance that amputation will stop the spread of bone cancer, although this does occasionally happen. The major reason to amputate in the face of bone cancer is for pain relief. Bone cancers tend to be very painful and amputation of a limb that has been affected by bone cancer can provide a great deal of relief as the source of the pain is removed. It is sometimes hard for veterinary clients, and even vets, to get past the fact that amputation isn' going to change the course of the cancer in most patients but that it is still a beneficial surgery. Pain relief is a worthwhile goal in its own right, especially when dealing with the degree of pain that can be associated with bone cancer.

Consider amputation of front or rear legs for small dogs and cats. Larger breed dogs tend to do OK with a rear leg amputation but seem to have more problems with front leg amputation. If bone cancer is affecting a front leg in a big dog I wouldn' want to rule out amputation but it is harder for big dogs to adjust to the loss of a front leg than for a cat or small dog to adjust. If a big dog isn' using the front leg, anyway, there is no reason not to consider amputation. There are some surgical procedures that can be used to remove the tumors without removing the entire leg but they are much more costly. The major effort in this direction has been at Colorado State University but other vet schools and larger referral centers are offering " sparing" surgery for bone cancers now, too. The companies that make wheeled carts for rear leg injuries also make wheeled mobility devices for front leg injuries and this may also be worth considering for a large dog who has trouble after a front leg amputation.

Persistent upper respiratory infections in cats

We have the best luck treating persistent upper respiratory infections in cats with azithromycin (Zithromax Rx). We generally use it three days in a row and then every other day but there are several dosing schemes that have been published and it is likely that others work about as well. This medication can be expensive but when nothing else is working it is worth the expense.

For cats with really chronic upper respiratory disease that responds to antibiotic therapy but then returns quickly it can be helpful to use the intranasal vaccines for feline herpesvirus (rhinotracheitis virus) instead of injectable versions and to vaccinate yearly rather than at longer intervals. Using these products twice when initially vaccinating, given one month apart, works better than just using a single dose according to Dr. Ford at NC State University. There are two suppliers of intra-nasal vaccines for cats and either one is supposed to work well. The manufacturers are Heska (Ultranasal tm) and Pfizer (Felimune CRV Intranasal tm). Many vets do not stock these vaccines because they often cause sneezing after administration and it is just too hard to explain this effect to people. Usually you can find a veterinarian within a reasonable distance who keeps these vaccines on hand, though.

Chronic gum infections in cats

Cats have a tendency to develop really severe gingivitis or periodontal disease due to an immune mediated disease, plasmacytic-lymphocytic gingivitis. This condition can be extremely painful and some cats even have persistent bleeding that shows up as bloody saliva. While many cats will respond to medical therapy with immunosuppressive drugs, some will not. It may sound like a truly desperate act, but removing all of the teeth other than the front incisors and the four big canine teeth can make these cats much more comfortable. This has to be done carefully because leaving even a small amount of root tissue can allow the reaction to persist, so it may be best to consider finding a dedicated veterinary dentist to perform the extractions. Most cats become much more comfortable after this procedure but it doesn' work for all cats. We have only had one patient who did not resume normal eating habits within a few days of the extractions when this procedure has been performed.

Chronic ear infections

Dogs are very prone to developing chronic ear infections that require long term management. In most cases the underlying cause of these infections is allergic disease, usually atopy (allergies to pollens, molds, etc). In cocker spaniels, springer spaniels and occasionally in other breeds the underlying cause of ear infections can be primary seborrhea, which is a defect in the way skin oils are produced.

It is possible to control the ear infections in some dogs through the use of ear cleansing products that have antibacterial and antifungal properties. There are a number of these products. We have had the best luck using products that contain tris-EDTA, such as Tris80 (tm) or TrisEDTA (tm) but ear cleansers that produce an acid environment such as Malacetic (tm), can also be effective. Just mixing vinegar with water in a 1 to 2 ratio (2 parts water) will work for many dogs. These products are difficult to use in some cases since patient cooperation can be minimal. Despite this, it is worth persisting with the cleansing. It works best to cleanse the ears twice a week but once a week will work for many pets. It is a lot of work to keep up with ear cleaning on a regular basis but when ear infections are chronic it can really pay off in reduced frequency of infection, which also saves money.

Sometimes pet owners just get tired of working with infected ears or their dog' ears continue to get worse despite steady effort to control ear infections. In these cases it is not uncommon for pet owners to seek a surgical cure. There are several different surgeries that are done. Lateral ear canal resection (removing only the outer wall of the ear canal ) is often recommended but usually doesn' completely resolve the problem. It may sound extreme to do this but if chronic ear infection has progressed to the point that surgery is necessary it makes more sense to do a total ear canal ablation -- removal of the entire ear canal and associated structures. This does produce deafness on the side that the surgery is performed on and can sometimes lead to facial paralysis but if surgery seems necessary this is the surgery most likely to produce good long term results. Total ear canal ablation should be done by a surgeon who has experience with the procedure and it is a good idea to consider asking for referral to a board certified surgeon if this procedure seems necessary.

Enucleation (removal) of eyes

There are several conditions, such as glaucoma, non-responsive tear deficiencies or cancer, in which it is best to remove the affected eye. Most of my clients will make the decision to remove one eye but are extremely reluctant to remove both eyes. This is a situation in which veterinarians often view the procedure as routine but veterinary clients think of it as a catastrophe. Veterinarians see blind dogs and cats fairly commonly and in most situations these pets are well adapted to their situation and they seem to be content with their lives. When the pet has severely decreased vision or is already blind, removal of the eye does nothing to make their lives worse and often makes them much more comfortable. Hopefully you will never find yourself in a situation in which it seems necessary to remove both eyes from a beloved pet but if you do, don' make the mistake of being overly attached to the mere presence of an eye, no matter how damaged it might be. If the eyes are a source of constant pain a pet is much better off without them, even though it is hard to accept sometimes.

Pain Relief

We have treated a handful of dogs over the years who came in due to problems with aggressive behavior who had no obvious signs of pain or discomfort but who improved dramatically in their behavior when we dispensed pain relief medications and they were given as directed. I think that it is reasonable to use pain relievers as a diagnostic tool in investigations of aggressive behavior in dogs, especially in older dogs and when the aggression is a new behavior in a dog that has not shown aggressive tendencies previously. There is little to lose by trying this approach and a lot to gain if it works.

Pain appears to be able to worsen many other diseases and disorders. This seems especially true for pancreatitis. While I can' classify this as true " medicine" I think it is important to put in a plug for pain relief when pets have illnesses that are painful in people. When your pet is ill or injured think about whether their condition would be painful if it happened to you. If it seems likely that it would be, ask your vet to provide pain relief medications for your pet.

True Desperation

One of my professors in vet school who had actually been a practitioner and who often had good advice in situations that seemed bleak offered this bit of advice one day:

" No pet should die of an unexplained illness without the benefit of glucocorticoid (corticosteroid) therapy"

Many of my clients have been well trained to avoid corticosteroids from friends, online contacts, pet health magazines and other sources. There are good reasons to avoid these medications unless they are necessary and to use them carefully, always trying for the lowest possible dose, preferably given every other day, when they are necessary. Despite the dire warnings, it is likely that glucocorticoids have saved more lives than they have ended and provided comfort more often than discomfort. When a diagnosis can' be made and there are no obvious contraindications to the use of corticosteroids or when euthanasia seems like the best option, there is no real reason not to use prednisone, dexamethasone or other glucocorticoids.

As has often been noted, desperate times call for desperate measures!

Brief Notes:

Carprofen (Rimadyl Rx) is now available in generic form. Right now the generic products are not a huge cost savings, although they are probably 20 to 25% less expensive than the brand name product. If past patterns hold the price of carprofen should drop steadily over the next few months as the generic firms get more and more competitive in their pricing of generic carprofen.

We have phone calls recently from clients who have purchased flea and tick medications, usually Frontline Topspot, online and received the product in packaging that indicates the weight in kilograms rather than pounds and has other variations from the EPA approved product sold in the United States. We get the phone calls because these clients usually have no idea how to convert the dosage from kilograms into pounds It is illegal to import products that would otherwise require EPA approval in the U.S. It would be a good idea to be cautious about companies that sell these products since there have been instances of counterfeiting of Frontline (tm), Advantage (tm) and other products. While that can happen even with the EPA procedures in the U.S., it seems like it would be easier to pass off counterfeit products in this manner. Be careful when ordering medications online. Try to be sure that you are getting products approved for use in the U.S.

Trilostane, an alternative to mitotane for the treatment of hyperadrenocorticism (Cushing' disease) in people, is available from Wedgewood Pharmacies, an online compounding pharmacy. Trilostane is more expensive than mitotane but appears to be safer to use and nearly as effective.

Colorado State University had developed a blood test for lymphoma in dogs, which may be useful when biopsy results are inconclusive or when lymphoma is suspected but accessible lymph nodes are not affected. At present the university lab is the only authorized testing site for this test.

Thanks for your Support!

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The opinions expressed in this newsletter are those of Michael Richards, DVM., author.