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www.southpaws.com WINTER 2011 8500 Arlington Boulevard Fairfax, Virginia 22031 Tel: 703.752.9100 Fax: 703.752.9200 IN THIS ISSUE: Iliopsoas Muscle Strains in Dogs Iliopsoas Muscle Strains in Dogs. . . . . . 1 CAROL WASMUCKY, BSPT, PET REHAB News and Celebrations . . . . . . . . 2 Updates from the Veterinary Cancer Society Meeting Fall 2010 . . . . . . . . . . 2 What’s New in Diagnostic Imaging at SouthPaws? . . . . . . 3 As “Eye” See It. . . . . . 4 Thoughts on Epilepsy Management . . . . . . . 5 Enhanced Endoscopy Services at SouthPaws . . . . . . . 6 Surgical Updates from the 2010 ACVS Meeting Seattle, WA . . . . . . . . 7 Over the past few years clinicians in the DC area have diagnosed an increasing number of Iliopsoas strains in dogs, most notably after last winter’s record snowfall and ice. The iliopsoas muscle runs along the groin with two originations (from the lumbar spine and from the ventral surface of the ilium) to attach to the lesser trochanter of the femur. This muscle is most often strained when the dog splays the hip. Injury occurs through repetitive trauma and movements associated with agility or work-related drills, as well as through activities where a dog repeatedly jumps over and through obstacles like snow, or sometimes, just slipping on slick surfaces. Symptoms of an iliopsoas strain are decreased stride length, limping (especially after exercise), as well as noticeably reduced hip extension, abduction, and internal rotation when the muscle is fully stretched. Rehabilitative treatments of iliopsoas strains are usually successful in returning dogs to full function. Treatment modalities include ultrasound, laser, ice, and electrical stimulation to decrease pain and inflammation, and promote healing. Massage and stretching to increase flexibility and decrease muscle spasm are also essential treatments. Dogs are started on a progressive strengthening program with exercises for the hip and core abdominal and trunk muscles. Activity modification is stressed as a key component of the rehab process. Gradual and closely monitored increases in a dog’s activities, in concert with treatment and exercise, allow our patient to return more quickly to full and pain-free function. 䡲 Hyperbaric Oxygen Therapy . . . . . . . . . . . 8 1 www.southpaws.com News and Celebrations at SouthPaws Updates from the Veterinary Cancer Society Meeting, Fall 2010 DR. STACY SANTORO, DACVIM (ONCOLOGY), SOUTHPAWS ONCOLOGY Mark your calendars now for the TENTH biannual CE Extravaganza on March 20,2011 where we’ll be hearing about thyroidal disease and I-131, surgical therapy for endocrine diseases, Addison’s disease, diabetic home care, imaging for endocrine diseases, head tilts/turns/ spins! On October 3, 2010, SouthPaws welcomed nearly 200 veterinarians, veterinary technicians and assistants to our ninth biannual CE Extravaganza. Thanks to our speakers Drs. Norton, Brehm, Dahlgaard, Gieg, Toal, Santoro, and Bromberg for another informative and exciting session. We really appreciate sponsors Antech Labs, Hill’s, MWI, Novartis, Pfizer, and Procter&Gamble for their continued financial support which allows us to provide six hours of free CE twice a year to lots of people! In September, 2010, SouthPaws was delighted to welcome back Dr. Matt Nelson, DACVR. Dr. Nelson was a SouthPaws intern after finishing his veterinary degree at Michigan State University, and then went on to complete his radiology training at the University of Georgia. With Dr. Nelson joining Drs. Cynthia Sloan, DACVR and Robert Toal, DACVR, you can now count on SouthPaws radiology for outpatient ultrasounds seven days a week. All of our radiologists are also happy to be participating in the BrightHeart Radiology Network, which enables us (and you!) to request radiographic interpretation from the radiologists that you know best! In July, 2010, we added a new CT machine. This Toshiba continued page 6 Transitional cell carcinoma (TCC) is the most commonly diagnosed urinary bladder cancer in dogs. It is a difficult tumor to treat and effective therapies are limited. The most commonly used chemotherapy agents include mitoxantrone and carboplatin along with piroxicam. A prospective trial using vinblastine was completed at Purdue University. Tumor response was evaluated using urinary tract ultrasound with bladder mapping on a monthly basis. Although none of the dogs experienced a complete remission, 36% had a partial response and 50% maintained stable disease. The majority of dogs tolerated the chemotherapy well. This abstract presents an alternative therapy for treating TCC in dogs, but the response is still less than ideal. Metronomic chlorambucil chemotherapy was also evaluated for the treatment of TCC. Metronomic chemotherapy refers to continuous, low dose administration of a chemotherapy drug with the intention of targeting tumor blood supply, not the tumor directly. Dogs received daily chlorambucil chemotherapy. Many of them had failed previous therapy and were currently taking a COX inhibitor. Only one dog had a partial response and about 65-70% had stable disease. The average time until progression was approximately 4 months. Similar to the vinblastine therapy, this study offers another option for dogs with TCC who have failed standard chemotherapy. At SouthPaws we use CCNU or lomustine at a standard, pulse dose manner to treat a variety of tumors including lymphoma, histocytic sarcoma, and mast cell tumors. Low dose CCNU was evaluated for tolerability when used in a metronomic daily dosing schedule to treat a variety of tumors. It was shown that almost 10% of dogs developed azotemia and many of them required discontinuation of therapy due to adverse side effects. Therefore, while CCNU is an option for metronomic dosing, azotemia is a serious side effect. One of the known side effects of CCNU used in standard dosing fashion is hepatotoxicity which can result in a life threatening problem in ≤5% of dogs treated with the drug. We routinely evaluate liver enzymes in patients receiving CCNU. Denamarin® is a supplement that includes SAMe and silybin used as a hepatoprotectant for many liver diseases. Its concurrent use in CCNU treated dogs was shown to result in less significant increase in liver enzymes. Administering Denamarin® with CCNU may be something to consider especially in patients with an increased risk! An exciting new option is available to treat dogs with lymphoma – peripheral blood stem cell transplantation (PBSCT)! This still-experimental treatment is currently performed at North Carolina State University. The ideal candidates are large dogs with B cell lymphoma that are free of coexisting disease. This treatment is a very complex and expensive process beginning after the successful completion of standard CHOP induction therapy, and involves high dose chemotherapy, bone marrow stimulation using Neupogen and harvesting of blood stem cells using an apheresis machine. The patient also has total body irradiation then receives an infusion of their own stem cells. It is a bit intimidating – all dogs have ZERO neutrophils and almost no platelets after the radiation therapy. They require intense management after the procedure, and several fatalities have been reported. This process takes 2-6 weeks of hospitalization at NCSU once standard chemo (which could be performed here at SouthPaws) has been completed, but offers hope for longer remissions or even a possible cure for dogs with lymphoma. We are happy to evaluate dogs with lymphoma to determine if they are candidates for this procedure and to discuss the details with interested clients. 䡲 2 www.southpaws.com What’s New in Diagnostic Imaging at SouthPaws? DR. MATT NELSON, DACVR, SOUTHPAWS DIAGNOSTIC IMAGING CENTER One slice, two slice, three slice, more slice! With the capability to acquire four slices with every rotation of the tube head, our new Toshiba Asteion Quad Slice CT is over four times faster than our previous unit. Adding that to a sub-second tube rotation time means that we can achieve high resolution, thin slices in a minimum amount of time. This allows us to acquire highly detailed images of small regions such as feline nasal passages without prolonging anesthesia time or to scan a medium to large-sized canine thorax without respiratory motion to confound interpretation. The case study below is an example of how having thin slices can make subtle abnormalities more pronounced. Figure 1. Axial computed tomography image of the skull, processed using an edge-enhancing convolution filter and displayed in a bone window for high detail of fine osseous structures. A 12 year old, neutered male, domestic short hair cat was presented for a chronic history of unilateral, right-sided nasal discharge. On physical examination, anisocoria was noted. List the computed tomographic findings and make your imaging diagnosis (answer on following page). The right orbital fissure is widened when compared to the left and filled with a soft tissue attenuating structure, which likely involves the structures transmitted through this opening (ophthalmic, oculomoter, trochlear, and abducent nerves). This mass minimally enhances following contrast administration. Additionally, lysis of the maxilla and hard palate were noted, and the mass tracked rostrally into the orbit. Soft tissue attenuating material was also present throughout the right nasal passage. Because of the pattern of lysis, soft tissue mass, and extension into the calvarial vault, neoplasia was considered most likely. Differential diagnoses include lymphoma, adenocarcinoma, and meningioma. Given this information, the owner elected to euthanize the patient while under anesthesia and did not permit necropsy. Figure 2. Same image with orbital fissure outlined (black arrows). was at first noted on only one slice and could have been attributed to slice artifact; however, the raw data was used to reconstruct 1 mm thick slices, and the abnormality became apparent on several slices. The thin, high resolution slices afforded by the CT scanner can give us valuable information in differentiating true from artifactual findings and, in this case, provide valuable information regarding prognosis. 䡲 Though the slices were initially acquired at 1 mm thick intervals, the computer reconstructed the images at 3 mm thickness for more rapid evaluation and a high signal to noise ratio. The asymmetry 3 www.southpaws.com As “Eye” See It NANCY M. BROMBERG, VMD, MS, DACVO, SOUTHPAWS OPHTHALMOLOGY “Your Patient Needs Bifocals” Several “normal” aging changes occur in the eyes of dogs and cats. Occasionally, these changes need to be differentiated from possible pathologic problems which may present in a similar manner. IRIS ATROPHY Thinning and atrophy of the iris sphincter muscle and/or the stroma of the iris is another frequent aging change. Atrophy of the iris sphincter muscle occurs significantly more frequently than does atrophy of the iris stroma. Thinning of the stroma is, however, seen commonly in Yorkshire Terriers and Toy Poodles. This atrophy may give the iris a lacy appearance, almost as if the dog has more than one pupil. The absence of a normal pupillary light response causes an inability for the eye to control how much light is entering it, causing the animal to squint in bright light. In some instances, avoiding exposure to bright sunlight might be indicated, walking the dog instead early in the morning and at or after dusk. LENTICULAR SCLEROSIS The most common change noted in the aging animal is lenticular sclerosis, or hardening of the lens. The hardening of the lens fibers doesn’t allow for the change in shape of the lens needed for focusing. As aging occurs in dogs, cats, and us humans, a point is reached where near vision becomes a bit out of focus without the help of “reading glasses”. In most people, this occurs in our forties. In dogs and cats it usually manifests itself about nine to ten years of age. Dog owners may recognize hesitancy with stairways, as the dog may have difficulty determining how far down that first step is. Occasionally owners may see a decreased ability to catch toys, or an occasional nip on the fingertip when giving a treat. With dogs in their teens, owners may notice a “flinching” response when the animal is approached, due to the lack of depth perception. Lenticular sclerosis rarely causes any major vision changes, just depth perception difficulties. Of course, dogs and cats with sclerosis would benefit from bifocals, but we’re not quite there YET! Atrophy of the muscles of the pupil sphincter causes a decreased pupillary light response, and dilation of the pupil. Since the atrophy may not be symmetric in both eyes, anisocoria is commonly diagnosed. The naturally occurring pupil sphincter atrophy needs to be differentiated from pathological abnormalities such as glaucoma, Horner’s syndrome, uveitis, other cranial nerve abnormalities, and other causes of anisocoria. ENDOTHELIAL DEGENERATION OF THE CORNEA The cornea is made up of three major layers, the outer epithelium, the inner-most endothelium, and the middle, largest part, the stroma, made up of layers of collagen. The collagen layers are arranged in layers, allowing light to pass through. A failure of either the epithelium or endothelium in keeping fluid out of the collagen layers causes the cornea to become edematous or cloudy with a blue-grey appearance. Lenticular sclerosis is sometimes referred to as “senile cataracts”, although this term can be misleading. With true cataracts, opacities exist within the lens, obscuring vision. Frequently the older dog with sclerosis may also develop concomitant cataracts. Thorough ophthalmoscopic examination of the fundus is essential when cataracts begin to appear to determine if the animal will be a candidate for cataract surgery if and when the cataracts progress. Continued on page 5 4 www.southpaws.com As “Eye” See It...Continued from page 4 With the forward motion of the fluid, the fluid may accumulate between the stroma and the epithelium, forming small bullae of “water blisters”. If these rupture, small recurrent corneal ulcerations may occur. This condition is known as Bullous Keratopathy. While there is no “cure” for this condition, it may be controlled with hyperosmotic 5% NaCl ointment. This may prevent the chronic reoccurrence of the ulcerations, and occasionally facilitates partial clearing of the cornea. The presence of corneal edema does have an effect on the animal’s vision. Because the cornea is no longer clear, it is somewhat like looking through frosted glass. When endothelial cells die, as a function of age, trauma, or inflammation, they are not replaced. The remaining cells enlarge and ‘move’ toward each other to fill up the space. As the eye is always under a certain amount of intraocular pressure, there is a forward movement of the intraocular fluid into the cornea. Under normal circumstances, the endothelial cells biochemically “pump” the fluid back into the anterior chamber, keeping the collagen fibers dehydrated. As more and more of the endothelial cells degenerate, the efficiency in which the remaining cells function decreases, and they allow fluid to enter the collagen. The collagen fibers swell and the cornea becomes edematous. It is common to see corneal edema due to endothelial degeneration in the older animal. There are inherited forms of this endothelial change, as seen in the Boston Terrier, Dachshund, and Airedale. Corneal edema associated with endothelial degeneration must be differentiated from corneal edema due to glaucoma or uveitis. 䡲 Thoughts on Epilepsy Management DR. MIKE KNOECKEL, DACVIM(NEUROLOGY), SOUTHPAWS NEUROLOGY/NEUROSURGERY in dogs. Concurrent treatment with phenobarbital increases metabolism of zonisamide, requiring a higher dose to achieve adequate tissue levels if both drugs are used in the same patient. Zonisamide has the advantage of a longer half-life in cats, requiring only once daily administration. I typically dose this at 10 to 20 mg once daily per cat. It is now available in generic form, making it much more affordable, though prices can still vary dramatically between pharmacies. Phenobarbital and potassium bromide have been the backbone of seizure management for many years in veterinary medicine. Many patients are well controlled on one or both of the drugs with few side effects. Unfortunately, some patients continue to seizure and some show unacceptable side effects such as hepatotoxicity with phenobarbital (uncommon but potentially very serious), asthma with potassium bromide in cats, and excessive sedation from either of these drugs. The sedative effects tend to be more pronounced when the two drugs are given together. Over the past few years, our choices have expanded with the introduction of zonisamide and leviteracetam. These newer medications are effective in dogs or cats where phenobarbital or bromide have not sufficed. Leviteracetam has also shown to be a very effective drug in dogs and cats with minimal side effects. Unfortunately, it does require TID dosing in most cases, which can be problematic for some pet owners. It has the advantage of being available in injectable form so it can be used in management of status epilepticus or refractory cluster-seizure Zonisamide is typically dosed at 5 to 10 mg/kg BID Continued on page 6 5 www.southpaws.com Enhanced Endoscopy Services at SouthPaws SOUTHPAWS INTERNAL MEDICAL Drs. Jennifer Gieg and Heather Hoch (both diplomates of ACVIM in Small Animal Internal Medicine) are pleased to announce that the endoscopy offerings at SouthPaws have been greatly enhanced in the last few months. Videoendoscopy along with both larger/longer and smaller/narrower scopes will enable endoscopic examination of a wider range of sizes of dogs/cats as well examination of more 'places' within these patients. Gastroduodenal, colonic/ileal, and esophagoscopy are now possible in very small (4 pound) to very large (150 pound) dogs, and most sizes of cats as well. With the addition of new basket and grasping retrieval devices, we have good success with removal of most gastric and esophageal foreign bodies and our internists are available to help with your foreign body emergencies 24 hours a day. With our flexible scopes urethroscopy and cystoscopy can also be performed in most medium sized male dogs. Rhinoscopy (retrograde and retroflex) as well as bronchoscopy (complete with cytologic brushings, BALs, and biopsy capabilities) in all sizes of dogs and cats is also possible here at SouthPaws. If you have a patient who would benefit from diagnoses obtained in these minimally invasive procedures, just give Drs. Gieg or Hoch a call and they'll let you know if your patient will "fit"! 䡲 In addition to our flexible scopes, we have rigid scopes to allow cytsoscopy and urethroscopy in most female dogs (10 lbs and larger) to aid in the diagnosis of urinary incontinence, cystitis / urethritis, and neoplasia. Theses scopes also allows vaginoscopy and examination of the vestibule for dogs with recurrent infections or vulvar discharge. Thoughts of Epilepsy Management...Continued from page 5 15-25 mg/kg TID (has a low but significant risk of hepatotoxicity and should not be given in combination with phenobarbital), topiramate at 10 mg/kg TID and gabapentin at 10 mg/kg TID. Over the past couple years, I have been very impressed with the effectiveness of pregabalin (Lyrica) starting at a dose of 4 mg/kg TID, though its price may be prohibitive in larger dogs. patients. I typically dose leviteracetam at 20mg/kg TID in dogs or cats, increasing the dose as needed to effect unless excessive sedation occurs. Either of these drugs can be added to pre-existing phenobarbital or bromide therapies, though that may increase the potential for sedation. Since I’m usually reaching for these medications when phenobarbital or potassium bromide have not been effective or have caused excessive side effects, I prefer to taper and discontinue the older medications as the newer drugs (zonisamide or leviteracetam) reach adequate tissue levels, typically over a two to three week period. Unfortunately, not all epileptics can be controlled with these medications and finding the best combination can be frustrating, analogous to ‘cooking without a recipe’ where we try adding a touch of this and removing some of that over time until we find the best combination to achieve the best control with the fewest side effects. 䡲 Other drugs that can be tried include felbamate at 6 www.southpaws.com Surgical Updates from the 2010 ACVS Meeting in Seattle, WA DR. DAN BREHM, DACVS, SOUTHPAWS SURGERY There is growing evidence that dogs with laryngeal paralysis may be clinically manifesting only one component of a progressive systemic polyneuropathy. In particular, esophageal dysfunction appears to be a common, concurrent problem, and may explain the comparatively high risk of aspiration pneumonia in laryngeal paralysis patients. A recent study at Michigan State University in which esophagrams were performed on laryngeal paralysis patients and compared to matched healthy dogs demonstrated significantly worse esophageal function in the laryngeal paralysis dogs. Also, the laryngeal paralysis dogs that developed aspiration pneumonia had significantly worse esophageal function than those dogs that did not develop pneumonia. Finally, one third of affected dogs had generalized neurologic signs on enrollment in the study, and all dogs had signs of polyneuropathy at study end (12 months). The esophageal dysfunction may be a result of concurrent degeneration of the pararecurrent laryngeal nerves, which branch off of the recurrent laryngeal nerves as they arise from the vagus nerve, and innervate the cervical and cranial esophagus. Although we are in the process of evaluating this information, it may be necessary to include assessment of esophageal function (via esophagram) as part of the diagnostic work up for laryngeal paralysis. If nothing else, findings of concurrent esophageal dysfunction may be important information for the owner in deciding how to approach treatment as well as understanding the level of risk associated with the treatment. Ultimately, the severity of the respiratory dysfunction is the most important factor in determining the necessity of corrective laryngeal surgery. Silver-containing dressings are widely used in human medicine to assist with management of infected wounds and those at risk for infection. They are now being used more commonly in veterinary medicine. One example of a silver-containing dressing is Acticoat Flex 3+7, from Smith and Nephew. This is a nanocrystalline silver impregnated dressing that is placed in the wound and hydrated with sterile water before being covered with a water-impervious outer dressing. The dressing can be left in place for up to seven days, although changes at 3-4 day intervals is preferred. When in contact with the wound, the dressing releases silver ions and kills bacteria by disrupting their cell walls. A wide range of bacteria are sensitive to this treatment, including Pseudomonas, methicillin-resistant Staph aureus, and vancomycin-resistant Enterococcus. This dressing also promotes granulation tissue formation in addition to its antibiotic effects. The Flex 3+7 dressing is flexible and malleable, and can be cut to match the shape of the patient’s wound. It is changed at appropriate intervals until the wound bed is healthy and can be definitively treated. Negative pressure treatment of open wounds has also become available for veterinary patients. Also known as vacuum-assisted wound closure (VAC), it entails exposing the wound bed to 7 local, sub-atmospheric negative pressure through a closed system to help with wound healing. The negative pressure removes fluid from the extravascular space, improving circulation and enhancing granulation tissue proliferation. The system entails placement of a sterile open cell polyurethane foam into the wound bed. A fenestrated egress tube is placed into a slot cut into the foam and connected to a vacuum system. The wound bed with the foam and the egress tube are then covered by an adhesive plastic sheet adhered to the surrounding skin to create a sealed cavity. Negative pressure is then applied to the wound (usually at around – 125 mm Hg). The bandages are changed every two to three days until definitive wound care can be applied. Studies in humans have demonstrated better wound closure and improvement in granulation tissue formation compared to wet to dry bandages. The use of honey in wound beds has achieved a resurgence in veterinary medicine. The high osmotic potential of honey debrides wounds and draws exudate from the wound bed. It also has anti-inflammatory properties and promotes granulation tissue formation. Antibacterial properties are through enzymatic production of hydrogen peroxide from glucose, and its hypertonicity, low pH, and inhibin content. Not all honey products work. Medicinal honey or Manuka honey are preferred and are used in open wounds during the inflammatory and early repair phases of wound healing. 䡲 www.southpaws.com Asteion Quad Slice has a rotation speed of less than 1 second, which means that we can image a large dog’s entire thoracic cavity in 20 to 30 seconds. Image quality is excellent, and three dimensional reconstruction is quite simple, quick and routine. CT is the best modality for imaging to provide diagnostic, prognostic and therapeutic information in many diseases of the head, neck, pelvis, abdomen and chest. Questions about when CT is preferred to plain radiographs, MR, or ultrasound? Just ask us! Our radiologists are happy to discuss options for optimal patient imaging. See Dr. Nelson’s article in this newsletter to get an idea on what type of very very small lesion can be seen with this this machine! DR. DAN BREHM, DACVS, SOUTHPAWS SURGERY At SouthPaws patients with challenging wounds can be managed with traditional means or the new methods outlined on page 5. We also have our hyperbaric oxygen therapy system readily available, which is of great value for many patients, particularly those with poorly healing wounds, and for skin flap and skin graft patients. “Cookie”, a dog burned in a house fire is looking out while getting HBOT. HBOT SAVES THE LEG: One patient that stands out was a cat who traumatically lost its forefoot (including all digits and all pads) at the level of the metacarpal bones. There was also a fairly sizable degloving injury from proximal to the carpus distally. The owner wished to preserve the leg if possible, so we used HBOT after debridement until a healthy bed of granulation tissue developed. A partial thickness skin graft was applied to the degloving injury, and a pad graft was placed at the distal end of the limb to create a new weight bearing surface. HBOT was again applied, and both the skin graft and pad graft took at near 100%. As of the last examination, the cat is using its pad-grafted leg nearly normally, with minor compensation for the slightly shorter limb. HBOT in this case gave the cat the best chance for graft take and preservation of near-normal limb function. 䡲 I-395 We thank you for your consultations and referrals in 2010—and greatly appreciate your confidence in our services. Hyperbaric Oxygen Therapy y Beltwa Our convenient new location: Just outside the beltway on Route 50 near Fairfax Hospital SouthPaws Veterinary Specialists & Emergency Center 8500 Arlington Blvd. Fairfax, Virginia 22031 Tel: 703.752.9100 Fax: 703.752.9200 DIRECTIONS TO FACILITY From the north and south directions on the Beltway take exit 50A US 50 West. Go to the second light, Javier Rd., and make a right. Make an immediate left onto Arlington Blvd. Frontage Rd., in front of the BB&T bank. Look for the paw print on the building. 8