Prophylactic Gastropexy | Leptospirosis | Patella Luxation | Toxic Pneumonitis | Meet Drs. Youjin Kim and Kim Egeler
Prophylactic Gastropexy for Gastric Dilatation and Volvulus
Made famous in the bestselling book “Marley & Me” by John Grogan, gastric dilatation and volvulus (GDV) is a life-threatening disease of dogs best treated with emergency surgery. As many as 30-45% of dogs afflicted with this condition will die, despite aggressive treatment. This is typically a disease of middle-aged, large, deep-chested dogs. The Great Dane, German shepherd, Weimaraner, Irish setter, Newfoundland, standard poodle and other similar breeds are over-represented, though the disease can occasionally strike any breed. Risk factors have been suggested, including feeding a single large meal, large kibble, exercise after meals, high-stress environments and recent anesthesia. There is certainly familial risk, in that animals with a first-order relative that has suffered a GDV are much more likely to have a GDV during their lifetime. Dogs with a history of foreign body ingestion or splenectomy may also be at an increased risk.
Dogs can have simple gas bloat, where air rapidly accumulates within the stomach without torsion, or GDV. In cases of GDV, the stomach becomes dilated and rotates on its axis, effectively creating an outflow obstruction. As air continues to accumulate, the stomach distends, obstructing venous return to the heart. The short gastric vessels often rupture, and ischemic damage to the gastric wall ensues with the increasing intragastric pressure. Devitalization of the stomach wall is a poor prognostic indicator for survival, as is the need for concurrent splenectomy. Once an animal has experienced an episode of either simple gas bloat or GDV, 60-70% of animals will experience recurrence within months. Therefore, surgical treatment is always indicated, whether the stomach has rotated or not.
Derotated necrotic stomach still distended with gas
Gastropexy procedures in which the fundus of the stomach is permanently affixed to the body wall reduce the risk of recurrence from >50% to <5%. Many variations of this type of procedure have been described, but the incisional gastropexy is the least technically demanding and most efficient to perform. Briefly, an incision is made in the pyloric antrum, approximately 4 cm in length. A corresponding incision is made on the right body wall, just caudal to the last rib. Two separate, continuous suture patterns are used to secure the stomach to the body wall. While not effective in preventing gas dilation of the stomach, a gastropexy prevents the life-threatening twist of the stomach on its axis.
Prophylactic gastropexy is offered as a preventive measure for at-risk dogs and is often suggested along with routine spay or neuter. This procedure is traditionally performed in open fashion, through a ventral midline incision. However, as minimally invasive procedures have become the standard in human medicine, veterinary owners are routinely seeking out these options for their companion animals. Advantages of minimally invasive procedures include smaller incisions, less post-operative discomfort, and earlier return to function.
Laparoscopic-assisted gastropexy involves placing a scope through a small incision just caudal to the umbilicus. A second instrument portal is placed just caudal to the last rib on the right body wall. Babcock forceps are introduced through this portal and used to grasp the pyloric antrum. The right body wall incision is elongated to an appropriate size for permanent gastropexy, and the pyloric antrum visualized. Stay sutures are used to manipulate the stomach, and a 4 cm seromuscular incision is created. Two continuous patterns are used to affix the pylorus to the inner body wall musculature. Closure of the subcutaneous tissue and skin completes the procedure. Ovariectomy or ovariohysterectomy can be performed concurrently.
Complications of prophylactic gastropexy are minimal. Incisional complications are most frequent, with seroma formation at the gastropexy site commonly reported. Mild, self-limiting vomiting has also been described. Post-operative care includes exercise restriction for 2-3 weeks, use of an e-collar for incisional protection, and administration of multiple small meals for 2-3 weeks as the gastropexy site heals.
Prophylactic gastropexy, whether performed via a standard open approach or via laparoscopic assistance, is a relatively simple procedure with few complications. The decision to pursue a gastropexy is one that ultimately lies with the owner; however, discussion regarding the procedure and GDV should be instituted early in the doctor-client relationship, when puppies are undergoing their vaccine series and contemplating spay or neuter. Education is the best means of prevention in high-risk breeds, and an early gastropexy may prolong both the quality of life and lifespan of these dogs.
We would like to thank our colleague from BluePearl in Kentucky, Patti Sura, DVM, DACVS, for allowing us to use this article for Companion.
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.
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.
This article is courtesy of our colleague from BluePearl in Washington, Brianna Backlund, DVM, DACVIM.
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; 222:1224-1229
Sykes 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.
Patella Luxation Update
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 scanners in our Grand Rapids and Southfield hospitals, we can take advantage of this technology to facilitate planning and improve outcomes.
Article courtesy of our colleague from BluePearl in Washington, Michael Weh, DVM, DACVS-SA.
Critical Care Corner: Toxic Pneumonitis
Brian Young, VMD, DACVIM, DACVECC
A four-year-old male neutered maltese presented to the emergency service for respiratory distress and coughing. He had recently been started on amoxicillin-clavulonate and azithromycin to treat possible Bordetella pneumonia a week after being at the groomer.
Physical examination showed normal temperature and tachycardia (150 bpm), with a respiratory rate of 60, increased inspiratory effort and harsh airway sounds in all fields. Bloodwork showed moderate eosinophilia and mild neutropenia. (The chemistry screen was normal.) Repeat thoracic radiographs showed worsening severe diffuse bronchointerstitial infiltrates.
He was hospitalized in the oxygen cage (SpO2 92% in oxygen, 86% out of oxygen). An endotracheal wash for cytology, culture and susceptibility was recommended but declined. Empiric therapy for resistant bacterial pnenumonia was started with a five-day course of amikacin to cover resistant gram-negative organisms (20 mg/kg IV q24h with ampicillin to increase efficacy) and chloramphenicol to cover for methicillin-resistant gram-positives (50 mg/kg PO q8h), both of which should be effective against Bordetella. The azithromycin was discontinued.
Severe bronchointerstitial pattern on right lateral radiograph
A heartworm test and fecal ova/parasites/Baermann tests were submitted (and later came back negative). Empiric albuterol, fenbendazole, clopidogrel and maropitant were added to the treatment plan. An echocardiogram was performed, which ruled out pulmonary hypertension. Coagulation testing was submitted, which later came back normal (platelet count, PT, aPTT, D-dimer).
Further questioning of the family revealed repeated exposure to an aerosol carpet cleaner used to clean his “accidents” on the carpet where he also liked to nap. The product contains hydrocarbons, known inhaled toxins associated with toxic pneumonitis1. Due to minimal improvement with two days of antimicrobial, oxygen and bronchodilator therapy, inhaled fluticasone was started for suspected toxic pneumonitis or inflammatory lower airway disease (eosinophilic infiltrates or chronic bronchitis). After three days, the patient was able to come out of the oxygen cage with a 95% SpO2.
Over the 8-day hospital stay, he showed gradual improvement. Recheck radiographs on day 7 of hospitalization were greatly improved, but not yet normal. He was discharged on day 8 with prednisolone (0.5 mg/kg/d) and chloramphenicol. He has made a full recovery and is currently off all medications. No good reason was found for eosinophilia. Toxic pneumonitis secondary to hydrocarbon exposure is the most likely cause of respiratory distress and pulmonary dysfunction observed.
A nonspecific, diffuse, transient, heavy interstitial pattern that is associated with severe oxygen-responsive hypoxemia and a protracted recovery is typical for toxic pneumonitis in dogs and humans. Known toxins include hydrocarbons, such as heptanes, petroleum distillates, propane, butane and benzene. These are found in waterproofing sprays, aerosol cleaners, gasoline, turpentine and kerosene. Recovery after several days of supportive care for dogs suffering from toxic pneumonitis has been reported with and without glucocorticoid therapy1. There is no evidence-based effective treatment; prospective double-blinded research trials are indicated.
BC Young, AM Strom, JE Prittie, LJ Barton. Toxic pneumonitis caused by inhaled hydrocarbon waterproofing spray in two dogs. JAVMA 2007; 231(1):74-8.
Medical Director’s Notes
Now that summer has ended and we are welcoming the crisp air of autumn, I wanted to take a moment to share with you some exciting additions to our Grand Rapids hospital. Dr. Yoojin Kim has joined our internal medicine team and will work in conjunction with Dr. Kristopher Sharpe to provide Monday through Saturday coverage. We also welcomed Dr. Kim Egeler to our surgery team. She will work alongside Dr. Amanda Conkling, and they will now provide Monday through Saturday appointments as well.
This issue of Companion focuses on internal medicine and surgery. Please take a moment to read the bios of both Dr. Kim and Dr. Egeler. They are valuable assets to the Michigan team, and I’m delighted to be working with them.
I’m also honored to be working with you. Nothing is more important than our relationship with the primary care veterinary community. We greatly value the trust and confidence you have placed in us by referring your patients to BluePearl Veterinary Partners in Michigan.
We would love to hear from you. Please call 248.354.6640 and feel free to share feedback or ask a question to be answered in an upcoming issue.
Meet Dr. Yoojin Kim
Internal Medicine Service
Originally from Korea, Dr. Youjin Kim worked in Seoul as a writer and editor before pursuing veterinary medicine. Within her field, Dr. Kim is particularly interested in nephrology, gastroenterology, immune-mediated disease and respiratory disease. We asked Dr. Kim some questions to help you get to know her better…
Dr. Yoojin Kim
How do you go about helping ease the concerns of an upset client?
The majority of my patients have one or more complex diseases. Many of them are not completely curable, and they have to live with their condition. It is upsetting as much as it is rewarding when we – the patient, the family, and myself – can get through it. I must admit that I am not afraid of showing my clients that I am upset or frustrated as well. However, I do not forget that I am the one who can help my clients understand what is going on with their pets and what can be considered for achieving a good quality of life for their family. Empathy, open-minded communication, and patience are the keys. I treat my patient as if he/she were mine and I discuss the diagnostic and treatment options with my clients as if they were my family or friends.
How do you like to work with the primary care veterinarian?
Primary care veterinarians are invaluable for successful care of a patient being seen in the internal medicine service where most patients have a chronic illness. The primary care veterinarian has a pivotal role in not only detecting any medical problem but also ensuring the ongoing care. Nothing makes my day better than when I hear from a primary care veterinarian that “so and so is doing great!”
Tell us about a case that stretched you as a clinician and taught you something meaningful about yourself and your practice.
During my residency, there was a young male cat diagnosed with pure red cell aplasia (PRCA), a rare bone marrow disorder characterized by a decline of red blood cells produced by the bone marrow. He suffered from severe recurrent anemia and did not seem to respond to treatment despite multiple blood transfusions and aggressive immunosuppressive therapy. His family and I felt defeated and concerned about whether it was time to draw the line. However, I extensively researched the disease in cats as well as humans and continued his treatment with the faith that he would start responding to therapy, which was supported by primary literature.
And he did! It took a few months, but he started turning around, and he has been doing fantastic ever since. I got to say goodbye to him and his family last month when I left the University of Minnesota. He made me proud and convinced me of the importance of my role as an advocate for my patients and also how critical it is to help my clients make the best decision based on evidence-based practice.
Dr. Kim Egeler
Dr. Kim Egeler
Dr. Kim Egeler is the newest member of our surgery team. She is especially interested in minimally invasive procedures including arthroscopy, fracture repairs and soft tissue procedures. Get to know Dr. Egeler…
Sometime during the first couple of weeks of vet school I came to the realization that there were options after graduation other than general practice. Being the “Type A” planner that I am, I immediately began exploring my options and shortly later decided on surgery for my future career; I instantly knew it was the place for me. I was always great with my hands and “crafty.” I loved the idea of finding the problem and then physical fixing it, often in creative ways. As I delved deeper into the field of surgery, I also discovered many other benefits for me. Every case, even the standard TPLO, has some new aspect to keep you thinking, researching, consulting and being creative. The surgical world also continues to advance with new research, technology and discoveries, mirroring human medicine as we go. There are always new instruments, approaches and techniques to explore. It is impossible to get bored and crucial not to lose touch with current medicine.
I am excited to work at a state-of-the-art hospital that allows me to work with arthroscopy, locking plates, a CT scanner and more every day. I have experts in oncology, internal medicine, dermatology, and ophthalmology working alongside me, never more than a short walk down the hall when I need a consultation. As a community, our doctors are encouraged to attend and contribute to continuing education frequently, which is the ideal environment for this quickly advancing field. I have the opportunity to work together every day with a community of general practitioners in order to provide optimal care, convenience and support to our clients.
Although, our jobs can be tough and emotionally taxing at times, I often find myself feeling grateful for the profession, specialty service, hospital and community I have the opportunity to work with.