2016 SPRING: Renton and Seattle Level I VECCS Certified | Leptospirosis | Unresectable Mast Cell Tumors | Canine Influenza | Chemotherapy Safety | Patella Luxation | Continuing Education
BluePearl Renton and Seattle Designated as Level I VECCS-Certified Facilities
To our colleagues in the veterinary community,
We are pleased to announce that the BluePearl hospitals in Renton and Seattle were recently granted certification by Veterinary Emergency and Critical Care Society (VECCS) as level I facilities and are now the only two veterinary hospitals in the state with this designation.
VECCS has defined a level I facility as “a 24-hour acute care facility with the resources and specialty training necessary to provide sophisticated emergent and critical patient care. This facility is open to receive small animal emergency patients 24 hours a day, 7 days a week, 365 days a year. The level I facility must have a Diplomate of the American College of Veterinary Emergency and Critical Care employed full time and available for consultation either on-site or by phone 24/7.”
We are proud to be recognized and to continue to support you and your patients.
Beth Davidow, DVM, DACVECC
BluePearl in Seattle
Linda Barton, DVM, DACVECC
BluePearl in Renton
Brianna Backlund, DVM, DACVIM
Despite vaccine availability, leptospirosis (infection with pathogenic species of the motile spirochete organisms of the genus Leptospira) is an emerging infectious disease of both humans and dogs. The newer vaccine has proven to be helpful in disease prevention. However, the vaccine has also led to complications when diagnosing active disease. With the advent of new tests for leptospirosis diagnosis, it is good to review the utility of these tests and to discuss which ones are most helpful for which patients.
Brianna Backlund, DVM, DACVIM
The conventional diagnostic test for leptospirosis is the microscopic agglutination test (MAT titers). This blood test involves reacting serial dilutions of the patient’s sera with a spectrum of pathogenic live serovars then evaluating organism agglutination via darkfield microscopy. This is considered the gold standard for diagnosis with both acute and convalescent titers and is available through several commercial laboratories. A positive test result is a four-fold rise in titer to a single serovar between acute and convalescent samples. A single MAT titer of >/=1:800 is the most commonly used cutoff titer with sensitivity and specificity reported to be 22-67% and 69-100% respectively. As this test evaluates the patient’s antibody response, titers can be negative (falsely) during the acute exposure period as the patient has not yet had the time to mount a measurable antibody response. Washington Animal Disease Diagnostic Lab (WADDL) does not charge for convalescent samples when the prior accession number is provided, an advantage of this lab. Convalescent titers should be submitted 10-14 days after acute titers. Vaccinations have a tendency to induce a low level titer across several serovars due to cross reactivity between serovars; although, no rise will be seen in any serovar in the convalescent samples.
Polymerase chain reaction (PCR) testing to detect nucleic acid of pathogenic leptospires is available through several commercial labs. This can be performed on both whole blood (preferred to sera) and urine. Whole blood is more likely to yield a positive result 0-7 days after infection, and urine seems to have the most success yielding a positive result after 7-10 days. PCR is helpful when the patient has been recently vaccinated as vaccination does not cause false positive results. To improve accuracy, it is best to perform both urine and blood PCR testing during the acute exposure period. PCR testing is most helpful when performed prior to antibiotic administration as antibiotics quickly clear the organism and lead to a negative test. A negative PCR does not rule out infection, but a positive PCR confirms infection.
The new ELISA snap test that is available is serology and simply gives a positive or negative test result. This test can be positive with both exposure and vaccination, so it is not very useful in a vaccinated animal. If the pet has not been vaccinated, it can be helpful, but seemingly most helpful when paired with PCR testing or MAT serology. For the snap test, 75% are positive at 1:100, 45% are positive at 1:200, and 100% are positive at 1:6400.
According to the 2010 ACVIM consensus statement, if clinical signs preclude oral doxycycline administration, starting treatment with ampicillin 22mg/kg IV q6h then transitioning to 5mg/kg doxycycline PO q12h for at least 2 weeks is appropriate. Some doctors still err on the conservative side and recommend a full four-week course of doxycycline therapy. Doxycycline is the best antibiotic for clearing the infection from the kidneys.
Fraune CK, Schweighauser Ariane, and Francey T. Evaluation of the diagnostic value of serologic microagglutination testing and a polymerase chain reaction assay for diagnosis of acute leptospirosis in dogs in a referral center. J Am Vet Med Assoc 2013; 242:1373-1380.Harkin KR, Roshto YM, Sullivan JT. Clinical application of a polymerase chain reaction assay for diagnosis of leptospirosis in dogs. J Am Vet Med Assoc 2003; 222:1224-1229Sykes JE, Hartmann K, Lunn KF, Moore GE, Stoddard RA, Goldstein RE. 2010 ACVIM Small Animal Consensus Statement on Leptospirosis: Diagnosis, Epidemiology, Treatment, and Prevention. J Vet Intern Med 2011; 25:1-13.
Management of Unresectable Mast Cell Tumors in Dogs
Sharon Shor, DVM, MS, DACVIM-Oncology
Mast cell tumors are the most common skin tumors in dogs. Their biological behavior is variable; most of the tumors are easily treated with wide-margin surgical removal, but some are more aggressive and carry higher potential for local recurrence and distant spread to the lymphatic system and visceral organs (such as liver and spleen). Local treatment can sometimes be very challenging, especially in situations where the masses are large and locally infiltrative, located at extremities of the body or when there is evidence of tumor spread to local lymph nodes or distant locations. Various forms of treatment have been evaluated for unresectable MCT in dogs including oral prednisone, lomustine (CCNU), Leukeran®, hydroxyurea and intravenous vinblastine (VBL); however, response rates are relatively low (~50% and less), and responses are typically short-lived. The tyrosine kinase inhibitor (TKI), toceranib phosphate (Palladia™), has proven, single-agent activity against canine MCT but tumor size reduction was found in less than half of the patients treated.
Sharon Shor, DVM, MS, DACVIM-Oncology
A recent article, “Pulse-Administered Toceranib Phosphate and Lomustine for Treatment of Unresectable Mast Cell Tumors in Dogs” (Burton J.H. et al., JVIM 2015; 29:1098-1104) evaluated a new approach for treatment of large mast cell tumors, where surgery was difficult to justify. The theory behind this study came from data supporting a synergistic effect for use of tyrosine kinase inhibitors (such as Palladia and sunitinib) in combination with chemotherapy and/or radiation therapy in different types of human and canine tumors. The combination of VBL and Palladia was already evaluated for dogs with MCT but significant dose reductions were needed in VBL dose due to severe bone marrow suppression. Chronic use of Palladia can also be problematic due to a wide range of complications (diarrhea, vomiting, lethargy, neutropenia, proteinuria and others).
The authors suggested that Palladia will sensitize tumor cells to chemotherapy and that low-frequency use will reduce its costs and side effects. This was a phase I/II, multicenter, prospective clinical trial that evaluated 41 dogs with measurable (>1cm) MCT confirmed by cytology or histology. The phase I CCNU dose-escalation portion of the study determined the maximum tolerated dose of CCNU. In phase II, Palladia was given only on days 1, 3 and 5 of a 21-day cycle, and CCNU was given on day 3 of each cycle. Most dogs treated were of middle to older age (median 8.2y), with a median weight of 28.2kg. Mixed breed and boxers were the most common breeds. The median tumor size was 6.7cm (range 0.84-21.8cm). Local lymph node and distant metastasis were found in 26 and 5 dogs, respectively. Side effects were mostly mild to moderate and included neutropenia (34 dogs), hepatotoxicity (24 dogs) and GI toxicity (vomiting, 15 dogs; diarrhea, 11 dogs). Overall, 16 dogs had CCNU dose reductions and/or treatment delays. The overall response rate was 46% (15 had partial remission, and 4 had complete remission). The median time to maximum response was 21 days, and median overall survival was 131 days. Dogs with tumors 6.7cm). Patients with no previous chemotherapy also had better MST at 146 days (vs. 50 days with previous treatment).
To summarize, pulse-dosed Palladia in combination with CCNU was well tolerated and caused less GI side effects than with standard frequency use of Palladia. The response rate here (46%) was comparable to other single-agent protocols but superior than reported in a recent multicenter study for use of CCNU as a single agent (23%). This protocol provides a good alternative for treatment of large mast cell tumors, and it may be more appealing to owners who decline parenteral chemotherapy treatment but cannot afford monotherapy with Palladia.
Beth Davidow, DVM, DACVECC
Influenza has now been diagnosed in our area, and as a result, we have been recently asked whether or not we recommend vaccination. As an emergency and specialty hospital we regularly rely on the expertise of our primary care partners to decide on their own vaccine protocols. However, since we do see a large range of cases, we can help speak to the incidence of disease in our area.
Since 2013, we’ve tested over 100 dogs with community acquired pneumonia using PCR for respiratory diseases. With these tests, we’ve primarily identified Bordetella bronchiseptica and Mycoplasma spp. We’ve also diagnosed several cases of distemper. We have not, however, identified influenza. Since influenza was identified in King County several weeks ago, we have performed additional PCR testing and serology through Cornell University on coughing and sneezing dogs seen in our Seattle and Renton hospitals. Again, no influenza cases have been identified.
To the best of our knowledge, in Washington, all recent influenza cases have been associated with one kennel in King County.
Would I recommend vaccination for influenza? Bordetella bronchiseptica is a far more widespread concern and would be a much higher risk in our area, so this vaccine would be my priority. We certainly should consider the influenza vaccination for dogs who frequent dog parks, doggie daycare or boarding, especially in south King County. It’s less of a priority for the Yorkie that spends most of his day on the couch and in his own backyard.
Our biggest role as veterinarians is to minimize spread of any disease that emerges. We continuously have to be on the alert in our hospitals for contagious diseases. We need to emphasize isolation and hand washing, and we need to proactively test to identify an outbreak quickly. My specific recommendations are:
- Make sure you have set receiving protocols for pets with signs of respiratory irregularities. These patients should be quickly moved into an exam room, out of the lobby, and away from other patients. If hospitalized, patients with potential respiratory diseases should be isolated. Staff handling these patients should wash hands thoroughly, change scrub tops after seeing a contagious case, and make sure to disinfect clipboards and stethoscopes between seeing patients. Any area where the patient has been should be thoroughly disinfected, including walls and areas where aerosol droplets could land.
- PCR testing should be strongly encouraged for dogs with respiratory disease, especially those with nasal discharge and fever, and those from kennels, doggie daycare situations, or those with a travel history.
- Any dog with respiratory signs should be confined and isolated from other dogs for at least 3 weeks.
- It is crucial that if anyone does see additional influenza cases in our area, those instances should be reported to public health so that rising incidence is caught early and communicated quickly.
Chemotherapeutic agents kill cancer by directly damaging DNA. These drugs also affect normal tissues, so cancer patients that have survived treatment can have a number of long-term side effects including damage to organs such as the liver, kidneys, lungs, heart and bone marrow; effects on reproduction and the developing fetus; and hearing impairment. Nurses who handle and administer chemotherapy have been shown to have higher indicators of mutagenic substances and chemotherapy metabolites in their urine. It has also been demonstrated that some family members of people on chemotherapy are exposed and have chemotherapy metabolites in their urine. Potential health risks of chemotherapy exposure include:
- Acute effects: skin rashes, allergies, hair loss, headaches
- Chronic effects: immune dysfunction, renal and liver dysfunction
- Effects on fertility and reproductive outcomes: infertility, spontaneous abortion, congenital malformations
- Associations with cancer: leukemia, carcinomas (breast, nasal, bladder)
In veterinary medicine we are at a unique and increased risk of exposure to these drugs because the most common practice is for one person to both prepare and administer the drugs. This is different from human medicine where the drug is usually prepared by a pharmacist and administered by a nurse. Another concern in veterinary medicine is the number of women of child-bearing age that are participating in patient care as spontaneous abortion has been a well-documented consequence of chemotherapy exposure. This could happen early in pregnancy prior to a woman knowing she is pregnant. Also with the increased use of oral chemotherapy agents in pets at home, there is a high risk of owners exposing themselves through improper drug or excrement handling.
It is important that PPE is worn to prevent inadvertent exposure to chemotherapy agents during drug preparation or administration.
Several groups have developed guidelines for the proper management of hazardous drugs including chemotherapeutic agents. These recommendations have been in place since the mid-1980s but there have been continued reports of occupational exposure. The National Institute for Occupational Safety and Health (NIOSH) issued an alert and developed guidelines to prevent exposure to hazardous drugs in the occupational setting. In Washington State, laws have recently been made to ensure that steps are being taken to protect employees in any job where exposure is likely (including veterinary medicine). The new guidelines proposed by Washington State will help decrease the risk of exposure to chemotherapy and protect workers and will in turn help protect employers from potential liability associated with employee health risks.
It is important to remember that chemotherapeutic agents are not the only hazardous drugs on the list. The definition of a hazardous drug is any drug that is carcinogenic, teratogenic or genotoxic; causes reproductive toxicity in humans; or can cause organ toxicity at low doses in humans or animals. Other drugs that are listed as hazardous and commonly used in veterinary medicine are*
*Taken from the NIOSH list of antineoplastic and other hazardous drugs in healthcare settings, 2014.
There are many points of potential exposure to a hazardous drug that must be considered when developing a safety plan for your hospital:
- Manufacture and packaging
- Shipping and receiving
- Drug preparation
- Drug administration
- Drug disposal
- Drug spills
- Drug metabolites in patient urine/feces
Steps to ensure safety can be taken at each of the potential points of exposure. Some general guidelines for safety in the clinical setting are listed below:
- Prepare and administer chemotherapy drugs in a dedicated room where eating and drinking is strictly prohibited.
- Draw up drugs in a biologic safety cabinet (see the CDC/NIH document Primary Containment for Biohazards: Selection, Installation and Use of Biological Safety Cabinets). One study documented that pharmacists using only horizontal flow cabinets had mutagenic substances in their urine, but those who used vertical flow Class II B biological safety cabinets did not.
- Wear appropriate personal protective equipment (PPE) to prevent exposure, including but not limited to gowns, chemotherapy-grade gloves, eye mask, face mask or respirator if aerosolization is possible. Change gloves every 30 minutes or if there is a puncture or tear. Gloves should cover the cuff of the gown. Use a full face shield or eye protection. Use a respirator with drugs that may vaporize at room temperature (e.g. carmustine, cisplatin, fluorouracil, cyclophosphamide, Mustargen®). Respirators need to be professionally fitted once a year.
- Utilize a closed system for delivering chemotherapy. Two examples of those available in veterinary medicine are Equashield® and PhaSeal®.
- Clean all surfaces and wash hands after chemotherapy administration.
- Dispose of chemotherapy agents and materials appropriately in closed hazardous waste bins NOT medical waste/sharps containers.
- Have a spill kit and plan available in the case that a spill should occur.
Protecting ourselves, our staff, our patients and clients can be achieved with careful implementation and monitoring of safety systems. It is a large undertaking, but the oncologists at BluePearl Veterinary Partners in Renton, Seattle and Tacoma comply with Washington State laws and guidelines and can provide safely administered chemotherapy to your patients. Please contact us with any questions or for consultations.
For a full list of the current laws, guidelines and deadlines for hazardous drug plans, please visit the Washington State Department of Labor & Industries website, lni.wa.gov/Safety/Topics/AtoZ/HazardousDrugs. They also have links to training programs and videos.
Other helpful websites:
- cdc.gov/niosh/docs/2014-138. This is the 2014 hazardous drugs list for 2014.
Connor, TH et. al. Preventing Occupational Exposures to Antineoplastic Drugs in Health Care Settings. CA: A Cancer Journal for Clinicians. 2006; 56:354-365.Valanis, B et.al. Occupational Exposure to Antineoplastic Agents: Self-Reported Miscarriages and Stillbirths Among Nurses and Pharmacists. Journal of Occupational & Environmental Medicine: August 1999; Volume 41, Issue 8:632-638.Yuki, M. et. al. Exposure of family members to antineoplastic drugs via excreta of treated cancer patients. J oncol Pharm Pract. 2013; 19 (3):208-17.
Patella Luxation Update
Michael Weh, DVM, DACVS-SA
Preoperative CT three dimensional reconstruction illustrating grade 4 MPL on the right stifle and grade 2 MPL on the left.
Patella luxation is a common orthopedic condition in dogs that may cause varying degrees of lameness, pain and progression of osteoarthritis. It is most commonly diagnosed in small breed dogs; however, large breed dogs may also affected. Both large and small breed dogs more commonly exhibit medial rather than lateral luxation (MPL). Lateral patella luxation (LPL) is rare in small breed dogs, but is more common in large breed dogs.
Etiology and Pathophysiology
Patella luxation in dogs is rarely the result of trauma. Most commonly it is due to congenital conformational abnormalities, resulting in malalignment of the stifle extensor mechanism. The extensor mechanism consists of the quadriceps muscle group, the patella, and the patellar ligament. The muscles of the quadriceps originate from the proximal femur and the caudal ilium, just cranial to the acetabulum. Extension of the stifle begins with quadriceps contraction. This force is transmitted to the patella, which articulates with the distal femur, and transmits the force to the patellar ligament. The patellar ligament inserts on the tibial tuberosity. During quadriceps contraction, the extensor mechanism must be aligned with the trochlear groove of the distal femur, or patella luxation results.
Malalignment of the extensor mechanism and the trochlear groove may be the result of a variety of skeletal abnormalities, from the hip to the proximal tibia. These include coxa vara/valga, femoral varus/valgus, tibial torsion and medialization of the tibial tuberosity. The most clinically relevant abnormalities are femoral varus/valgus and medialization of the tibial tuberosity.
In addition to extensor mechanism malalignment, dogs with patella luxation may exhibit a shallow trochlear groove, erosion of the medial trochlear ridge, varying degrees of degenerative joint disease and periarticular fibrous tissue proliferation. Most of these changes are probably secondary to extensor malalignment.
Patella luxation is graded on a scale of I-IV:
- Grade I: The patella can be luxated with manual pressure, but immediately reduces when pressure is released.
- Grade II: The patella can be luxated with manual pressure, and spontaneously luxates during ambulation. It easily reduces by extending the stifle or by manual pressure and resides in the trochlear groove a majority of the time.
- Grade III: The patella resides outside of the trochlear groove a majority of the time. It can be reduced by manual pressure.
- Grade IV: The patella resides outside of the trochlear groove continually and cannot be reduced.
Standard lateral and cranial-caudal radiographs of the stifle should be taken to rule out concurrent orthopedic conditions and evaluate conformation. A luxated patella may be visible on radiographs; however, grade I and II luxations are intermittent, and the patella may appear reduced at the time of radiography. Varying degrees of joint effusion and degenerative joint disease may also be seen. A V-D pelvic radiograph, including the stifles and proximal tibiae can help to evaluate femoral conformation. With a straight film, femoral varus/valgus can be assessed. However, findings on this view can be misleading, especially if the hindlimbs are internally/externally rotated or adducted/abducted. Caution should be used when diagnosing varus/valgus or torsional abnormalities, and multiple radiographs may be necessary. For more complex deformities, computed tomography can be useful in diagnosing the underlying malformation.
The decision to surgically correct patella luxation is based primarily on clinical signs. If a dog shows persistent (greater than a few weeks) or recurrent lameness (greater than a few episodes), even if intermittent, surgery should be considered.
The majority of dogs with patella luxation can be corrected by deepening the trochlear groove, transposing the tibial tuberosity, and resection/release of medial/lateral fascia. For cases with significant varus/valgus deformities of the femur, or rotational deformities of the femur or tibia, corrective osteotomies may be necessary to align the extensor mechanism.
Prognosis for dogs following surgical correction of MPL is very good to excellent. Multiple studies have graded outcomes of excellent or good in >90% of operated cases. The best outcomes and fewest complications seem to occur when techniques to address trochlear groove depth, tibial tuberosity position, and soft tissue redundancy all are performed together. The most common complications are implant failure and persistent luxation. However, only a minority of dogs with persistent luxation exhibit lameness on follow-up examination.
Several studies in recent years have focused specifically on the role of excessive femoral varus in contributing to patella luxation. In certain patients, especially large breed dogs, evaluating distal femoral varus and correcting this when it is excessive helps improve outcome and decrease likelihood of persistent or recurrent luxation following surgery. In cases with complex angular limb deformities related to patella luxation, computed tomography can be particularly useful. The CT scan allows reconstruction of imaging data in multiple plans for ease of evaluating limb alignment as well as three dimensional reconstruction and modeling for pre-surgical planning. With the CT scanner in our Seattle hospital, we can take advantage of this technology to facilitate planning and improve outcomes.
BluePearl is strongly committed to the veterinary community. One of the ways we demonstrate this commitment is through our continuing education program, which is subsidized in part by our Partners in Education.
All BluePearl CE lectures are free and and include dinner 30 minutes prior. Please RSVP to 206.364.1660 or Sonja.firstname.lastname@example.org. For the most current information about BluePearl CE, please check our online calendar regularly.
|Apr 20||7PM||Doctor||Respiratory Distress: How to Not Hyperventilate When They Hyperventilate|
Mitchell Fults, DVM, DACVECC
|May 11||7PM||LVT||Critical Thinking for the Technician: Labwork Interpretation|
Melissa Hoemann, LVT, VTS(ECC)
|North Seattle College Room||2 hr|