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Month: August 2017
The 2015 AKC Canine Health Foundation Conference
By Laura Liscum on behalf of the PBGVCA Health Committee
In August, the AKC Canine Health Foundation (CHF) sponsored the 2015 National Parent Club Canine Health Conference in St. Louis. Linda Murray and I attended the conference on behalf of the PBGVCA and the PBGV Health & Rescue Foundation, respectively. We both thought that it was a fabulous experience with excellent talks, abundant opportunities to interact with the speakers, and lots of free dog chow! Here is a synopsis of several presentations that we heard at the conference.
Stem Cells Therapy for Supraspinatus Tendonopathy.
Dogs injure ligaments and tendons while chasing bunnies in the field, running agility courses and roughhousing at doggie daycare. Like their owners, many dogs develop osteoarthritis after years of activity. The traditional surgical repair, medications and rehabilitation therapy have not always restored the injured dog to his/her pre-injury state. Two years ago, we heard Dr. Sherman Canapp describe his remarkable results when traditional treatment approaches are combined with stem cells or platelet-rich plasma therapy. His work continues to look very promising.
This year we heard Dr. Jennifer Barrett from Virginia-Maryland Regional College of Veterinary Medicine. Barrett described her collaborative studies with Canapp using stem cells and platelet-rich plasma to heal 57 agility dogs with shoulder injuries that had been lame for more than a yeardespite treatment with non-steroidal anti-inflammatory drugs, steroids and sessions in rehab. Dogs were treated with stem cells, which are undifferentiated cells that are able to divide and develop into specialized cells that repair and replenish adult tissues. They also treated the dogs with platelet-rich plasma isolated from the canine patient’s blood. Platelets are a natural source of bioactive proteins and growth factors that stimulate collagen formation and healing of tendons and ligaments. In fact, platelet rich plasma is currently being used to treat human and equine athletes. The dogs received pre-treatment analysis of gait and limb movement. Then stem cells and platelets were isolated and injected into the soft tissue lesions, guided by ultrasound.
The dog returned each month for ultrasound gait and limb movement analyses. The site of injury was examined by arthroscopy at 90 days. The outcomes of this study were very encouraging! The AKC CHF is now funding Drs. Barrett and Canapp to conduct the first randomized, placebocontrolled clinical trial of stem cells and platelet-rich plasma for supraspinatus tendon injury. They are having a difficult time enrolling enough dogs for the trial, so if you have an injured dog, please inquire.
Regenerative Medicine
Techniques to Treat Cartilage Disorders. Complaints about aching joints are not limited to the athletic canine. Couch potatoes can get injured too. In fact, 80 percent of all dogs have orthopedic joint disease at some point. One type of joint disease is called osteochondrosis, in which the joint’s cartilage becomes damaged. If a weakened flap of tissue breaks off, the piece may absorb minerals and harden. Imagine what it would feel like to have a pebble floating around in your joint! Unfortunately, joints do not regenerate healthy tissue very well. Dr. William Saunders, from Texas A&M, described a method for healing degenerated joints in which a plug of tissue is taken out of a non-weight-bearing portion of a dog’s healthy joint and grafted into the same dog’s damaged joint. This autograft can successfully restore function to the formerly damaged joint. However, this is like robbing Peter to pay Paul — the donor site now has a weakened cavity. Dr. Saunders’s goal is to develop a method to strengthen the donor site. His approach is to create replacement plugs made of porous polyethylene glycol and seeded with healthy bone-derived stem cells. In his preliminary studies, he placed these artificial plugs into the donor sites, and the stem cells within the plug populated the joint. This is an important step in bringing the autograft therapy method to the clinic.
Personalized Cancer Treatment.
Most treatment strategies for cancer use a standard approach in which all individuals with a particular cancer are treated with the same standard drug therapy. Unfortunately, this approach fails to take into account the molecular differences between individual cancers. Precision medicine is a new approach in which treatments are selected only after an individual’s tumor has been profiled to find specific gene mutations that led to their cancer.
Dr. Douglas Thamm of Colorado State University is investigating Toceranib, a therapeutic for mast-cell tumors that is used when surgery is not curative. Toceranib, marketed as Palladia, is the only dog-specific anti-cancer drug that is currently approved by the U.S. Food and Drug Administration. It acts by binding to a specific protein in tumor cells. Dr. Thamm hypothesizes that treatment with Toceranib will only be successful on dogs whose tumors are due to mutation of that specific protein. To test this hypothesis, Dr. Thamm has developed a rapid test that can be performed on fine-needle aspirates. The test can rapidly determine whether a dog’s mast-cell tumor has the mutation so that a therapeutic decision can be made within days. This test is the first step toward personalized medicine in the treatment of canine mast-cell tumors.
Atopic Dermatitis and the Mycobiome.
“You’ll Never Walk Alone” is a Rodgers and Hammerstein song from the musical Carousel. When he wrote the lyrics in 1945, Hammerstein had no way of knowing that when you walk through a storm, at least 100 trillion bacteria walk with you. In fact, 90 percent of our body’s cells are bacteria! We truly never walk alone. Fortunately, the microbes that colonize us are non-pathogenic symbiotic bacteria and fungi that are critical for our health. The abundance of these friendly microbes keeps the pathogenic organisms at bay.
Dr. Jan Suchodolski from Texas A&M is studying the canine mycobiome, which is the dog’s fungal community. He has determined that “the skin of dogs is inhabited by much more rich and diverse microbial communities than previously thought.” His recent publication [Hoffman, 2014] showed that each dog has a unique community of microorganisms, and each area of a dog’s skin harbors a unique selection of microbes. Healthy dogs have from 25 to 40 different species in their nostrils and up to 866 species in an ear! The composition of the microbial community did not appear to be influenced by dog age, sex, breed, itchiness, ear problems or indoor/outdoor environment. However, there was a significant difference when healthy dogs were compared to those with atopic dermatitis, or allergies. Dogs with allergies had fewer species of microbes than healthy dogs. Future work is needed to determine whether the reduced diversity of the skin mycobiome in allergic dogs isthe cause of, or the result of, the animal’s hypersensitivity to allergens. It is not known if the skin mycobiome shifts during allergic episodes. Finally, the possibility exists that restoring the microbe community to healthy levels will help treat atopic dermatitis.
Senior Cognition and Brain Aging.
Are you slower to get out of bed in the morning? Can’t remember who that person in front of you is? Finding it harder to negotiate a familiar environment? Have a decreased attention span and a loss of knowledge? Feeling anxious about all of these changes? These are questions that you should be asking your senior dog. From about six years of age on, your dog will begin to exhibit signs of brain aging that are so subtle that you may not notice them. Signs that are severe enough for you to notice include new fears or phobias, separation anxiety, soiling in the house, waking at night, vocalization and repetitive actions. Many owners do not report the first signs of aging to their vet because they think that nothing can be done. But there is evidence that early intervention may help.
Dr. Gary Landsberg from the North Toronto Veterinary Behaviour Specialty Clinic has extensive experience in testing cognition in senior dogs. Senior dogs get Alzheimer’s-like brain changes and have measurable deficits in learning and memory. When cognitive dysfunction is suspected, a vet must first rule out medical issues, and conduct neurological and sensory physical exams. Dr. Landsberg is also director of Veterinary Affairs at CanCog, a contract organization that specializes in non-invasive research on canine cognition and general behavior. His videos of the CanCog Beagle colony illustrated a typical cognitive test. First, let a dog learn a task such as quickly finding the food treat that is under the large box, but never under the small box. Once the task is learned, you present the dog with a reversal task by putting the treat under the small box. Young dogs quickly learn that the task has been reversed, whereas older dogs take significantly longer. But it turns out you can teach an old dog this new trick if you have provided the dog with an enriched environment. Dr. Landsberg said that you should make a senior dog work his/her brain everyday! He cited several pharmaceuticals that he prescribes for dogs that are showing cognitive dysfunction. He said that senior dogs show improvement with the medications individually and do even better when they are in combination. He encouraged owners to ask their vets for help. He also recommended two foods for dogs older than six; they are Hills b/d Canine and Purina Bright Minds (discussed below). Both have additives that help senior dogs maintain learning and memory skills.
Bright Mind Platform.
The brain is the most metabolically active organ in the body. At rest, the human brain uses up to 25 percent of the body’s energy even though it only accounts for 2 percent of the body’s mass. When challenged by a Sudoku puzzle, the energy needs go up. That energy is obtained from glucose that enters brain tissue from the blood. The situation is similar in dogs. Dr. Gary Penn, from the Nestlé Research Center, explained that dogs begin to show behavior signs of aging because their brains lose the ability to metabolize glucose around the age of 7. Investigators at the Nestlé Research Center explored alternative energy sources and found that adding medium chain triglycerides to the food increased the ability of dogs at the CanCog facility to perform cognitive tests. I was so convinced by the evidence that medium-chain triglycerides help maintain cognitive function that I bought a coconut-oil dietary supplement for myself. If only I could remember to take it!
The Human-Animal Bond/Quality of Life Scale.
If you are an avid reader of Saber Tails, that probably means that your passionate relationship to your PBGV(s) governs your life. From the house you buy and the car you drive, to the clothes you wear and places you vacation — PBGVs rule! This extraordinarily close human-animal bond makes it difficult when your dog is terminally ill. The keynote speaker for the CHF conference was Dr. Alice Villalobos, the former president of both the American Associationof Human Animal Bond Veterinarians and of the Society for Veterinary Medical Ethics. Dr. Villalobos has an animal oncology consultation service in Woodland Hills, Calif., and an animal hospice, called Pawspice, in Hermoso Beach, Calif. The Pawspice mission statement says, “Pawspice is committed to the highest standard of compassionate cancer treatment and end-of-life palliative care to advanced stage and terminal pets by providing a unique Quality of Life Care Program.”
According to Dr. Villalobos, we need to be able to distinguish between normal senior life and end of life in our pets. In the past, veterinarians were not trained to give pets palliative care; she is trying to change that. She has developed a quality of life scale that assesses seven characteristics, which are Hurt, Hunger, Hydration, Hygiene, Happiness, Mobility and More good days than bad days. The scale is intended to help caregivers and family to monitor and improve a pet’s well being, and help them know when palliative care and hospice may be warranted, rather than curative treatment. Dr. Villalobos stressed the importance of providing terminally ill pets all necessary medications, effective pain management, adequate nutrition and hydration, proper hygiene, assistance with mobility to maintain muscle mass and healthy joints, and contentment.
The Pawspice website (pawspice.com) has excellent resources for pet owners who are facing difficult end-of-life decisions. Go to the site and click on Library to find articles on Dr. Villalobos’s quality-of-ife scale or to view her seminar at the August 2015 Southern California Veterinary Medical Association Symposium. There is also information on many types of cancer and when it is time for euthanasia.
The 2015 National Parent Club Canine Health Conference also featured presentations on gastric dilatation volvulus (commonly known as bloat), intestinal inflammation, infectious diseases, brucellosis and seizures. You will read about those talks in a future issue of Saber Tails.
Conditioning Puppies for Hunting
By Mary Fluke, DVM
September 2015
When I started hunting with Iris, she didn’t have a clue what she was doing, never went in the cover, just ran the lanes and made no progress until after several hunts when she finally tripped over a rabbit. I’ve watched a lot of novice dogs try to start out in the hunt field and have seen other handlers go through the same frustration that I experienced. For dogs with no experience, whether or not they succeed in the field has more to do with luck and persistence than anything the owner can do to help them. I still remember the moment when I saw the light bulb go off for Iris, when she finally figured out that she could go in the briar patch and rustle up her own bunny and have the fun of following the trail.
Most of us get our puppies from breeders who have the show ring as their main focus. They do a wonderful job of socializing puppies, but hardly anybody makes the effort to condition puppies for hunting. When I decided to breed Iris, I had to come up with a plan to condition the puppies for hunting so they would have a head start in the field.
A few years ago, one of our judges (Sian Kwa) presented a seminar at a hunt on this very topic. She gave a memorable example using a durian (the King of all Fruit, a very stinky sulfurous fruit which tastes like butter if you can overlook the sulfites) to show that things that we smell and taste when we are very young will be familiar forever and have good associations, even though we might not appreciate them so much if we are exposed as adults. Puppies that will be raised for drug detection start playing with plastic cylinders loaded with the smell of illicit drugs while still in the whelping box. Sian, who raises Dachshunds for blood tracking, has her puppies playing with deer feet and eating deer meat as soon as they go on solid food.
I used this information to create a plan for conditioning my puppies for hunting. I started with freeze-dried bunny ears and feet, and also freezedried rabbit jerky. Once the puppies were about three weeks old, I started letting them play with the ears and feet at least once or twice a day. They showed a lot of interest and persistence, and I kept this up until Oak got big enough that one day he swallowed one of the bunny ears whole! After that, I had to be a little more circumspect in how I offered them the bunny bits.
I had taken care of the problem of early exposure to the scent. Now I needed to get the puppies used to going into cover. Fortunately, the puppies were born in the fall so the season was prime for pruning. I used branches to create a brush pile in the back yard. When the puppies were five to six weeks old, I started taking them outside to eliminate after eating and to start walking around on the outdoor surfaces (asphalt and grass). They were interested in the brush pile and played in the edges. I wanted them to be a little more adventurous, so I made a “drag” using a couple of freeze-dried bunny feet tied to a piece of twine. I threaded the twine through the brush pile, and then had a helper release a couple of puppies at a time so they could follow the drag through the brush pile. The puppies had a lot of fun working their way over and through the branches, and the best part was that I could do this in my own back yard, no running grounds required, no hunt field needed. This exercise was tons of fun to do, nothing cuter than puppies worming their way through a brush pile.
One of the beagle guys from our local club was nice enough to fix me up with a San Juan rabbit (halfway between domestic and wild). As the puppies grew up, I gave them the chance to see and smell the rabbit in a cage. Not quite the same as turning puppies loose in a one-acre practice pen like the beagle guys do, but again, I was trying to devise a plan that anybody could do. Domestic rabbits aren’t the same as wild rabbits in terms of smell and behavior, but any rabbit is better than no rabbit — the point is to give the puppy some kind of context to connect “that smell” with “that animal.” The puppies showed some initial fearfulness when they had a chance to get close to the bunny (in a small wire cage on the ground), but they soon got over their caution and started barking and sniffing. One caveat for this exercise is to be careful to avoid the fear period that usually occurs around eight weeks — if the puppy is exposed to the caged rabbit at this critical point, the progress for hunting might be slowed down.
The final exercise was following a trail. I went to a bloodtracking seminar a few years ago and heard a couple of guys from Germany talk about conditioning puppies for following scent trails. One of the presenters said that he used buttermilk to draw a line on the floor, and then let the puppies follow the line — again, easy to do on the kitchen floor where the puppies are being raised. I tried using a drag with bunny “scent in a bottle” and food treats to create trails for the pups to follow, indoors and outdoors.
I am lucky enough to have access to a running grounds, so I had the opportunity to get the puppies on the hunt field by 10 to 12 weeks. They followed me into cover, used their noses consistently and showed wonderful promise as hunting dogs. Three of the pups from that litter have gone on to hunt very enthusiastically, and are well on their way to completing their hunt titles.
So breeders, what the heck, let the puppies play with freeze-dried bunny feet, ears or pieces of a pelt. Feed them some bunny meat, freeze dried or fresh, when they start eating solid food. Puppy buyers, when you get your new PBGV puppy, make a brush pile in your back yard and get some bunny feet to make a drag so you can introduce your new puppy to cover. Take your puppy to a meadow with tall grass, or to the woods with some low undergrowth to encourage exploration and use of nose.
Exposing the puppy to a rabbit might be a little harder from a logistical standpoint, but hopefully you can go to a hunt and participate in a puppy or novice learning experience with a caged rabbit. Use your bunny foot drag to make a trail, and drop a little piece of food every foot or so to get your puppy off to a start on tracking. These exercises are fun and pretty easy to do, even in a suburban environment. (And don’t forget to practice your recall!)
Conditioning puppies for hunting isn’t hard at all. Give it a try!
Nutrition of Aging Dogs
By Jennifer A. Larsen, DVM, PhD and Amy Farcas, DVM, MS
Vet Clin Small Anim 44 (2014) 741-759
When do our PBGVs transition from being adults to seniors? The American Animal Hospital Association suggests that dogs are considered to be seniors when they are in the last 25 percent of their predicted lifespan. The typical healthy PBGV has a lifespan of about 12 to 14 years, which means that PBGVs transition from adult to senior around 10 years of age.
How do the nutritional needs of our PBGVs change as they age? This question was addressed by Dr. Jennifer Larsen, Associate Professor of Clinical Nutrition at the University of California Davis School of Veterinary Medicine, and Dr. Amy Farcas, of the University of Pennsylvania School of Veterinary Medicine Clinical Nutrition Service. Drs. Larsen and Farcas note that older dogs may have normal physiologic changes that occur with aging and pathologic changes due to disease. Both types of changes may benefit from nutritional intervention.
Normal physiological changes associated with an aging PBGV (as well as his/her aging owner!) include changes in body composition and reduced metabolic rate. In general, older dogs have a reduced lean body mass and resting energy requirement accompanied by an increase in body fat mass. It is important to monitor body condition since obesity can exacerbate age-related diseases. Surprisingly, senior dogs have a higher prevalence of being underweight, which may be due to undiagnosed pathologic conditions. Studies have shown that senior dogs absorb nutrients as well as young dogs; however, their protein requirement increases most likely due to increased protein turnover.
Many pet food manufacturers offer canine diets targeted towards the senior population. It is important to be aware that the ideal nutritional profile of a diet for senior dogs has not been agreed upon. Thus, there is wide variation in energy density, nutrients and supplements in the senior diet.
Pathologic changes in the senior dog that may respond to nutrition include cognitive dysfunction, declining immunity and degenerative joint disease. Studies have shown that a diet enriched in anti-oxidants leads to improved behavior score, social interactions, sleep patterns, agility, learning, and recognition in dogs with cognitive dysfunction. Keeping a PBGV mentally active with games that use his/her nose may also be helpful. Dietary enrichment of anti-oxidants and vitamins also improved some aspects of immunity as measured by laboratory tests, although there was no measure of immunity of dogs against infectious disease.
The prescription for preventing degenerative joint disease in dogs is the same as for humans — maintain a healthy weight, incorporate exercise into your daily routine and eat a balanced diet. As dogs and their humans age, sarcopenia (loss of muscle mass) is a major problem that can be alleviated by meeting the requirements for protein in the diet and using the muscles. A number of nutritional supplements have been touted to be effective for treating degenerative joint disease. These include fish oils that contain long chain omega-3 polyunsaturated fatty acids, green-lipped mussel extract, glucosamine and chondroitin. Unfortunately, there is still no clear consensus for the effective dose or delivery of these compounds or method of assessment.
Drs. Larsen and Farcas note that it “should be kept in mind that each of the nutraceuticals discussed earlier for the management of age-related diseases have either an incompletely assessed efficacy or have conflicting results between subjective and objective assessments or between studies.” They conclude by saying “As dogs age, they experience a wide variety of metabolic changes that affect both structure and function. These changes may consist of normal, physiologic aging changes or may manifest as age-related disease. Screening for these changes via routine physical examination and laboratory assessment is critical to affecting the processes at stages where their courses may be altered. Accommodating the specific changes observed in each individual, rather than adopting a generic senior dog approach, will allow tailoring a patient’s treatment plan to the individual’s needs.”
The Role of Neutering in Cancer Development
By Annette N. Smith, DVM, MS
Vet Clin Small Anim 44 (2014) 965-975
Many PBGVs in the PBGVCA community are reproductively intact because they are being actively shown or are in breeding programs. What about the dogs who are retired from the ring, are no longer being bred or are family pets? The advantages of neutering the latter group of dogs are well documented. A spayed bitch doesn’t worry about pyometra, isn’t surprised by an unplanned pregnancy and no longer has to shop in the feminine hygiene aisle of the supermarket. A castrated male is less likely to roam, fight or mount inappropriately. In addition, neutering leads to decreased risk of mammary, ovarian and uterine tumors of the female, and testicular tumors of the male. What’s not to like?
Dr. Annette Smith is Professor of Clinical Sciences at the Auburn University College of Veterinary Medicine. Her clinical specialty is oncology. Dr. Smith has gathered information from published studies on the effect of surgical sterilization on the occurrence of cancer.
Her article cites several studies that have found an increased risk of certain tumor types in surgically altered dogs. For example, osteosarcoma is more common in large and giant breeds, and neutered dogs of those breeds have a two-fold high risk for this diagnosis. Several studies have found the risk of hemangiosarcoma is many-fold greater in neutered females than intact, whereas the risk for males was less. The risks for both lymphoma and transitional cell carcinoma are higher in neutered dogs of both sexes.
Dr. Smith cites a study published in 2013 that examined the causes of death among more than 40,000 dogs presented to North American veterinary teaching hospitals from 1984 to 2004 (Hoffman, Creevy, and Promislow, 2013, PLOS ONE 8:e61082). The authors found a slight increase in life expectancy in sterilized dogs as compared to intact; however, they found large differences in the cause of death. Sterilized dogs of both sexes were much less likely to die of infectious disease (i.e., parvovirus, heartworm, canine distemper, intestinal parasites), trauma, vascular disease and degenerative disease. In contrast, the sterilized dogs were more likely to die of cancer (i.e. transitional cell carcinoma, osteosarcoma, lymphoma, mast cell tumors) and immunemediated disease. The relationship between sterilization and risk of cancer was seen in all size classes of dogs.
The bottom line is that neutering has positive effects on behaviors, noncancerous diseases and lifespan that outweigh the increased risk of cancer. It is unclear why sterilization has an effect on the risk for cancers outside of the reproductive system. Owners should be aware of the risk of cancer in their neutered hounds and discuss this with their veterinarians. Dr. Smith concludes by saying “In un-owned, shelter or rescue populations, the population benefits of neutering likely outweigh any potential for increasing cancer risk. For owned animals, veterinarians will need to discuss the pros and cons for each individual and determine the best strategy for that pet based on breed, lifestyle, longevity expectations, concurrent diseases, cancer risks, other considerations for intact and sterilized dogs, and owner preferences.”
Metronomic Chemotherapy in Veterinary Patients with Cancer: Rethinking the Targets and Strategies of Chemotherapy
By Barbara Biller, DVM, PhD
Vet Clin Small Anim 44(2014) 817-829
Most of us have had a loved one stricken by cancer and, thus, we are familiar with the conventional cancer chemotherapeutic approach. Traditionally, a cancer patient is treated with a high dose of a drug, or drug combination, that is more toxic to rapidly dividing cancer cells than to normal tissues. The patient typically suffers side effects such as nausea, hair loss and fewer red blood cells. The treatment is followed by a break to allow drug-sensitive normal tissues to recover. Then the treatment is repeated. This conventional chemotherapy has led to improved survival for many cancer patients, but it often fails.
Dr. Barbara Biller is a veterinary oncologist at the Flint Animal Cancer Center, affiliated with Colorado State University. Her research, funded in part by the AKC Canine Health Foundation, is testing a new approach to cancer chemotherapy, called metronomic chemotherapy. A metronome is a device that produces a regular tick, tick, tick that musicians use to keep a steady tempo. Metronomic chemotherapy is the daily administration of a low dose of the same toxic drugs as conventional chemotherapy. This low dose doesn’t kill the tumor cells, but there is evidence it does prevent the growth of blood vessels into the tumor. Starved of nutrients, the tumor dies. The metronomic dose also appears to “wake up” the immune system, leading to an antitumor immune response.
Metronomic chemotherapy has been tested in several human clinical trials with patients who had advanced cancer that had failed to respond to conventional chemotherapy. Dr. Biller reports that, despite promising results, metronomic chemotherapy is still considered investigational and is not offered as a first-line therapy.
Dr. Biller cites nine published clinical trials of metronomic chemotherapy in dogs and cats. The treatment is easy to administer, reasonably priced and well tolerated. There is early evidence of overall clinical benefit. Dr. Biller states, “Although metronomic chemotherapy is an attractive treatment choice, it is still considered an experimental approach with the potential for toxicity. When available, conventional therapies should first be offered before turning to a metronomic protocol. Because stable disease is generally the goal of therapy, it is also important to consider the overall condition of the patient; living with stable disease should be expected to result in an acceptable quality of life. When used appropriately, there is much potential for metronomic chemotherapy to improve, not just maintain, quality of life for companion animals with cancer, especially as additional studies answer important questions regarding indications, drug dosages and patient monitoring.”
Status Epilepticus and Cluster Seizures
By Edward (Ned) E. Patterson, DVM, PhD
Vet Clin Small Anim 44(2014) 1103-1112.
Epilepsy is a disorder of the brain that is characterized by recurring, unpredictable seizures. The seizures are likely due to uncontrolled electrical activity in regions of the brain, which can produce behavioral changes. When no specific cause for the seizures can be found, the disease is known as idiopathic epilepsy (IE). Young dogs (less than 1 year of age) that experience seizures often do so because of exposure to an infectious agent or to a developmental anomaly. However, the seizures could also be due to an inherited degenerative disease or metabolic disorder. Most dogs that experience their first seizure when they are much older than 5 years of age most commonly do so because of a tumor, or a late-onset degenerative or metabolic disorder. IE is the diagnosis when a specific cause for the seizures cannot be found. It typically occurs in between these very early and late cases, with an age of onset between 1 and 5 years. IE is only diagnosed after all other causes of the seizure activity have been ruled out. Most dogs with IE have a normal lifespan. However, dogs that experience seizures lasting at least five minutes or who have multiple seizures without recovery in between (known as status epilepticus) typically have a reduced survival time.
Dr. Ned Patterson is an epilepsy clinician and researcher at the University of Minnesota Clinical Investigation Center. His Canine Epilepsy Network (www.canine-epilepsy.net) is a wonderful online resource for owners and breeders of affected dogs, as well as clinicians and researchers. He gave an excellent health seminar on epilepsy at the 2009 PBGVCA National in Tucson.
In this recent article, Dr. Patterson focuses on the need for urgent and aggressive treatment for seizures that last more than a few minutes or occur back-to-back without recovery. He cites the statistic that 40 to 60 percent of dogs with idiopathic epilepsy suffer cluster seizures or status epilepticus. These are emergencies that can lead to irreversible neuronal damage. Prolonged or frequent seizures can also lead to heart and kidney damage.
Dr. Patterson outlines the general standard of practice for canine status epilepticus. Unfortunately, there has not been an expert panel consensus statement for treatment of the canine disease, as there has been for human status epilepticus. Dr. Patterson states, “There does seem, however, to be fairly similar recommendations from a number of sources that can be generally summarized as:
“1. First-line therapy should be with a benzodiazepine, which most often is intravenous diazepam, but can be by other routes and/or with midazolam, or lorazepam. There have not been any published studies comparing benzodiazepines to each other in dogs or cats as there has been for people. Shortly after the benzodiazepine, there should be intravenous loading or mini loading doses of intravenous phenobarbital or intravenous [levetiracetam] to start chronic therapy, for when the short-acting benzodiazepines wear off.
“2. In second-line therapy for continuing seizure activity, intravenous phenobarbital or intravenous LEV or a [constant rate infusion] of diazepam or midazolam should be given. The author has found that two or more of these second-line therapies can potentially be given to the same patient.
“3. Third-line therapy of [refractory status epilepticus] to induce general anesthesia can be with intravenous propofol or pentobarbital. In some instances, IV ketamine or inhalant anesthesia has been administered.”
Research over the past decade has tested new approaches, which Dr. Patterson hopes will lead to paradigm shifts in treatment for seizures. These include neurosteroids, gene therapy, use of molecules that alter gene expression, and new biochemical targets. Dr. Patterson concludes, “Status epilepticus in companion animals is an emergency and should be quickly treated by recommended first-line (emergent) therapy with benzodiazepines followed by loading doses of chronic therapy drugs, and then secondline, and third-line (refractory) therapy when needed. Cluster seizures can evolve into status epilepticus, and therefore at-home treatment with per rectum or intranasal benzodiazepines and longer-acting oral antiepileptic drugs for dogs is often recommended, and if not effective, then hospitalization for observation and treatment as for status epilepticus are recommended.”