JAAHA 56.3 Abstracts

Abstracts from issue 56.3 of JAAHA, Journal of the American Animal Hospital Association.

56.3 MAY/JUN 2020

Editor in Chief

Alan H. Rebar, DVM, PhD, DACVP, Purdue University, West Lafayette, Indiana

Associate Editor

Linda Ross, DVM, MS, DACVIM (SAIM), Tufts University, North Grafton, Massachusetts

Managing Editor

Karie Simpson

JAAHA, Journal of the American Animal Hospital Association, is published as an official scientific and educational publication of the American Animal Hospital Association. The purpose of the journal is to publish accurate, timely scientific and technical information pertaining to the practice of small animal medicine and surgery. JAAHA is available in print and online. Log onto jaaha.org for more information. If you are interested in becoming a reviewer for JAAHA, please contact jaaha@aaha.org.

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ORIGINAL STUDIES

Low-Level Laser Therapy for Osteoarthritis Treatment in Dogs at Missouri Veterinary Practice

Brenna K. Barger, Adam M. Bisges, Derek B. Fox, Bryan Torres

A qualitative survey was electronically distributed to practicing veterinarians in the state of Missouri to evaluate the frequency of use and economic impact of low-level laser therapy (LLLT) for the treatment of osteoarthritis (OA) in dogs in Missouri. The survey response rate was 10% (89/867). Approximately half (43%) of respondents had LLLT units, of which all used LLLT for OA treatment in dogs. In respondents without LLLT units, 20% referred patients for LLLT OA treatment. Training was most often obtained in-house by a representative of the LLLT unit manufacturer (76%). Treatment dose was largely unknown and chosen by predetermined settings on the LLLT unit (65%). In the majority of patients (84%), no treatment site preparation is performed. An average of four patients with OA were treated per wk with an average cost per treated joint of $28 (range: $15–45). This study provides insight into the current clinical use and estimated annual economic impact ($6.2 million per year) of treating a single OA joint in dogs with LLLT by Missouri veterinarians. The frequency with which LLLT is used in the treatment of OA combined with the variation in training and treatment protocols supports the need for further research regarding the application and efficacy of LLLT in dogs with OA. Read the full article

RETROSPECTIVE STUDIES

Nimustine Treatment of 11 Cases of Canine
Histiocytic Sarcoma

Hiroyuki Tani, Sena Kurita, Ryo Miyamoto, Harumi Sawada, Aki Fujiwara-Igarashi, Masaki Michishita, Daigo Azakami,
Daisuke Hasegawa, Kyoichi Tamura, Makoto Bonkobara

The objective of this retrospective study was to report treatment outcomes in dogs with histiocytic sarcoma (HS) that were treated with nimustine (ACNU). This study evaluated data from 11 dogs including 5 with macroscopic tumors that were treated in the primary setting and 6 that underwent aggressive local therapy while being treated in the adjuvant setting. The median ACNU starting dose was 25 mg/m² (range, 20–30 mg/m²; 3- to 5-wk intervals, 1–8 administrations). The median overall survival in the primary and adjuvant settings was 120 days (median progression-free survival [PFS], 63 days) and 400 days (median PFS, 212 days), respectively. Neutropenia was observed in eight cases (grade 1, n = 1; grade 2, n = 2; grade 3, n = 2; grade 4, n = 3) with nadir neutrophil count at 1 wk after ACNU administration. Mild gastrointestinal toxicity (grade 1–2) was observed in three cases. ACNU was well tolerated and showed a similar outcome to that seen for lomustine, which is a drug commonly used to treat canine HS, in terms of overall survival and PFS in the current study population. Further investigations will need to be undertaken to definitively determine if ACNU is an appropriate alternative to lomustine for the treatment of HS. Read the full article

RETROSPECTIVE STUDIES

Cholelithiasis in the Dog: Prevalence, Clinical Presentation, and Outcome

Patricia M. Ward, Kieran Brown, Gawain Hammond, Tim Parkin, Sarah Bouyssou, Mark Coia, Genziana Nurra, Alison E. Ridyard

Canine cholelithiasis is considered to be an uncommon condition and is frequently cited as being an incidental finding. However, there is a paucity of contemporary literature to support these assertions. The aim of this retrospective cross-sectional study was to report the prevalence, clinical presentation, and long-term follow-up of cholelithiasis in dogs. The electronic database at the Small Animal Hospital, University of Glasgow was searched to identify dogs that were diagnosed with cholelithiasis on ultrasound between 2010 and 2018. Sixty-eight dogs were identified, giving an overall prevalence of cholelithiasis in our hospital of 0.97% (confidence interval 0.76–1.22%). Medical records of 61 dogs were available for review. Cholelithiasis was classified as an incidental finding in 53 (86.9%) dogs, with 8 (13.1%) dogs being classified as symptomatic, having complications of cholelithiasis that included biliary duct obstruction, biliary peritonitis, emphysematous cholecystitis, and acute cholecystitis. Follow-up was available for 39 dogs, with only 3 dogs (7.7%) developing complications attributed to cholelithiasis, including biliary duct obstruction and acute cholecystitis, within the subsequent 2 yr. Cholelithiasis is an uncommon but frequently incidental finding in dogs. Within the follow-up, few of the dogs with incidental cholelithiasis went on to be become symptomatic. Read the full article

RETROSPECTIVE STUDIES

Association Between Exposure to Ehrlichia spp. and Risk of Developing Chronic Kidney Disease in Dogs

Wade Burton, Corie Drake, Jennifer Ogeer, Jesse Buch, Rebekah Mack, Donald McCrann, Michael Joseph Coyne

Ehrlichiosis is a common vector-borne disease caused by Ehrlichia spp. This retrospective matched cohort study was performed to determine if dogs with Ehrlichia spp. antibodies had an increased incidence of chronic kidney disease (CKD). Exposure to Ehrlichia spp. was defined as having an Ehrlichia spp. antibody–positive result recorded at any point in their available patient history. The outcome of CKD was defined as concurrent increased symmetric dimethylarginine (>14 µg/dL) and creatinine (>1.5 mg/dL) for a minimum of 25 days with inappropriate urine specific gravity (<1.030). Patients were matched using propensity score matching to control for age, geography, and breed. A total of 22,440 patients and controls in E canis–endemic regions of the United States were used in this analysis. Contingency tables were used to compare dogs with and without exposure to Ehrlichia spp.–infected ticks and CKD outcome. The relative risk of CKD for patients exposed to ticks carrying Ehrlichia spp. was found to be 2.12 (95% confidence interval [1.35–3.15], p < 0.0006). This study identified that testing positive for Ehrlichia spp. antibodies in E canis–endemic regions is associated with higher incidence of CKD in dogs. Read the full article

CASE REPORTS

MRI Findings in a Young Boxer with Septic Physitis of the Humerus

Rachel Kakas, Stephen Stockdale, Alaina Carr

The MRI appearance of appendicular septic physitis has not been reported in small animals. MRI appearance of septic arthritis and osteomyelitis has been described in horses, and the use of MRI has been proposed as a diagnostic alternative to radiographs to allow for earlier diagnosis and treatment. MRI is also routinely used in human medicine for the diagnosis of osteomyelitis owing to increased accuracy of evaluation of the soft tissue involvement. In the case of a 5 mo old male boxer dog described here, radiographs were suggestive of the diagnosis of septic physitis, although an MRI was obtained to rule out neurologic etiologies of lameness based on history and physical exam findings. MRI identified a fluid pocket communicating with the physis. The diagnosis of septic physitis was then confirmed via ultrasound-guided fine-needle aspirate of the fluid pocket communicating with the physis that was seen on the MRI. Read the full article

CASE REPORTS

Successful Surgical Correction of Congenital Colonic Duplication and Anogenital Cleft in a Cat

Christina Fruehwald, Gary Ellison

A 17 wk old sexually intact female domestic shorthair kitten presented for an anogenital cleft and enlarged colon. The cat had experienced bacterial cystitis and constipation since weaning. Contrast referral images revealed an enlarged colon with a patent anus. Clinical examination revealed an anogenital cleft with a common anovulvar orifice. The rectum was patent upon digital rectal palpation, and fecal contamination of the vulva was present. Abdominal radiographs revealed two distinct colons, both filled with a moderate amount of formed fecal material. Contrast-enhanced computed tomography revealed segmental duplication of the descending colon with a dominant right colon and a smaller accessary left colon. The two structures conjoined at the transverse colon proximally and at the pubic brim distally. A common anogenital orifice with anovulvar communication was also noted. The anogenital cleft malformation was successfully repaired surgically. A celiotomy was performed to remove the smaller accessory colon. An ovariectomy and partial hysterectomy were also performed. The patient recovered uneventfully and showed no gross evidence of recurrent cystitis or urinary or fecal incontinence postoperatively. This is believed to be the first report of a congenital anogenital cleft and complete communicating colonic duplication in a cat. Read the full article

CASE REPORTS

Combined Surgical, Radiation, and Medical Therapies for Osteochondrodysplasia in a Scottish Fold Cat

Yukihiro Fujita, Tetsuya Nakajo, Tom Ichinohe, Takuya Maruo

Osteochondrodysplasia affects both homozygous and heterozygous Scottish Fold cats, and various treatments have been attempted to control chronic pain and improve mobility in these animals. However, to date, there is no single effective treatment that can be used to treat all cats with Scottish Fold osteochondrodysplasia (SFOCD). A 4 yr old castrated Scottish Fold cat presented with plantar exostoses in the right hindlimb, the largest of which was caudal to the tarsometatarsal joint and had stretched the overlying skin, causing ulceration and bleeding. There was right hindlimb lameness. The cat was diagnosed with SFOCD, and the skin lesions were treated by excision of the exostoses, removal of the damaged skin, and wound closure. All extremities were treated with radiotherapy and subcutaneous pentosan polysulfate for chronic pain. The cat’s gait improved after surgery, and increased activity was noted after radiotherapy. There were no signs of excessive bone proliferation or adverse effects at 80 wk postoperatively. In conclusion, a combination of surgical, radiation, and medical therapies could be an effective treatment strategy for SFOCD with skin ulceration. Read the full article

CASE REPORTS

Upper Airway Obstruction Due to Primary Laryngeal Blastomycosis in a Dog

Lauren Green, Laurie Cook, Margaret Martinez, Eric Green

A 4 mo old spayed female mixed-breed dog was presented for focal lower motor neuron signs of the right forelimb and marked hyperesthesia on axillary palpation. Her signs progressed rapidly over the following days to diffuse lower motor neuron signs in all limbs and a seizure. MRI demonstrated a focal, slightly right-sided, 2.5 cm region of noncontrast-enhancing T2 hyperintensity and T1 isointensity at C4–C5 spinal cord segments. Imaging of the brain was unremarkable. The dog was euthanized as a result of poor prognosis. Polymerase chain reaction on cerebrospinal fluid and immunohistochemistry of brain tissue were both positive for canine distemper virus. This report documents an atypical presentation of canine distemper encephalomyelitis causing lower motor neuron signs and hyperesthesia. Read the full article

CASE REPORTS

Gastric Intravascular Lymphoma in a Dog: Case Report and Literature Review

Alexandra Guillén, Matteo Rossanese, Emanuele Ricci, Alexander James German, Laura Blackwood

Intravascular lymphoma (IVL) is a rare, high-grade, extranodal lymphoma characterized by selective proliferation of neoplastic lymphocytes within the lumen of small vessels. A 10 yr old female intact mixed-breed dog was presented with a 7 mo history of vomiting and anorexia. Physical examination revealed abdominal discomfort. Ultrasonography and endoscopy identified a submucosal gastric mass. Excision was performed by partial gastrectomy and histopathology and immunohistochemistry confirmed a T-cell IVL. The owner declined chemotherapy, and the dog was instead treated palliatively with prednisolone. Two months after surgery, vomiting recurred and abdominal ultrasonography revealed a large gastric ulcer with focal peritonitis. The dog was euthanized 4 mo after initial presentation and postmortem examination confirmed IVL recurrence in the stomach and an isolated nodule of neoplastic cells in the omentum. No involvement of other organs was found following histopathological examination. This is the first description of primary gastric intravascular lymphoma causing chronic vomiting in a dog. Read the full article

CASE REPORTS

Excessive Cyclosporine-Associated Immunosuppression in a Dog Heterozygous for the MDR1 (ABCB1-1Δ) Mutation

Andrew J. Mackin, Caitlin Riggs, Todd Beatty, Katrina Mealey, Dawn Boothe, Todd Archer

Pharmacodynamic monitoring was used to titrate cyclosporine dosing in a dog with immune-mediated hemolytic anemia. Development of a suspected secondary infection, with subsequent discovery of an unexpectedly high level of T-cell suppression despite a relatively low cyclosporine dose, prompted an investigation into the cause of possible excessive immunosuppression. Blood cyclosporine concentrations were within expected target ranges, and the dog was determined to be heterozygous for the multidrug resistance protein 1 (MDR1; ATP-binding cassette sub family B member 1-1Δ) gene mutation. The MDR1 mutation was suspected to have contributed to the excessive immunosuppression experienced by this patient. This case highlights the need to monitor immunosuppressive therapy in the individual patient, especially when the patient is not responding to therapy at typical dosages or when secondary infections develop at dosages lower than expected to cause significant immunosuppression. Pharmacodynamic monitoring can be used to help identify unexpected excessive immunosuppression in dogs receiving cyclosporine, and MDR1 genotyping should be further explored as a potential method of predicting and preventing its occurrence. Read the full article

ONLINE CASE REPORTS

Spontaneous Regression of a Mandibular Plasmacytoma in a Juvenile Dog: A Case Report

Erika Villedieu, Samuel Beck, Laurent Findji

A 4 mo old female Finnish lapphund presented for further investigation of a swelling of the right rostral mandible. A computed tomography scan showed the swelling to be an expansile and osteolytic mandibular lesion. Histopathology revealed a poorly differentiated, moderately well-demarcated, unencapsulated, highly infiltrative round cell neoplasm, and immunohistochemistry was supportive of a plasmacytoma. Performance of a rostral partial mandibulectomy was initially discussed with the owners, but the lesion improved spontaneously both clinically and on repeated computed tomography scanning before surgery could be performed. It subsequently almost completely resolved 6 mo after diagnosis. Hypotheses for spontaneous regression of the lesion are discussed and the human literature is briefly reviewed. Read the full article

ONLINE CASE REPORTS

Obturator-Assisted Prolapse for Access to and Sampling of Colorectal Masses in Seven Dogs

Ewan Wolff, Laura Van Vertloo, S. Kathleen Salisbury, Michael O. Childress

The gold standard for diagnosis of colorectal masses is surgical biopsy; however, this is not always logistically or economically feasible. The authors present an alternative to established flexible and rigid endoscopic approaches when case limitations require such an approach. In seven dogs, after the identification of a mass on physical exam and computed tomographic evaluation, the colorectum was accessed using obturator-assisted prolapse to isolate discrete masses and perform shielded sampling via core needle biopsy. Histopathologic diagnosis was adequate for treatment planning in all dogs. No major complications were recorded 65–475 days after the procedure. This technique may be useful when traditional endoscopy and surgery for biopsy of colorectal masses is unavailable. Read the full article

ONLINE CASE REPORTS

Uretero-Cutaneous Fistula and Renal Abscessation as a Complication of Ureteral Stenting in a Dog

Xavier Montasell, Marilyn Dunn, Mila Freire

An 11 yr old female spayed shih tzu was referred for treatment of left ureterolithiasis with complete obstruction of the left ureter and pyonephrosis. A ureteral stent was placed surgically to relieve the obstruction and pyonephrosis was treated with antibiotics. Three and a half years following stent placement, the patient developed an abscess on the left flank with chronic purulent discharge. Diagnostic imaging confirmed the presence of a left uretero-cutaneous fistula and renal abscess. A left ureteronephrectomy was performed. The dog was euthanatized 4 mo later for cardiac insufficiency unresponsive to medical treatment. This is the first report of a uretero-cutaneous fistula and renal abscessation as a complication of ureteral stenting in a dog. Read the full article

ONLINE CASE REPORTS

Trapped Neutrophil Syndrome in a Border Collie

Ashley K. Hegler, Amy M. Grooters, Shannon D. Dehghanpir, Rebekah A. Gallaher, Lorrie E. Gaschen

A 10 wk old female border collie was presented for hemorrhagic diarrhea and pelvic limb lameness. Examination revealed pain and effusion in multiple appendicular joints and pyrexia. Clinicopathologic testing revealed moderate neutropenia as well as nondegenerate neutrophilic inflammation in multiple joints. Radiographs showed capsular joint swelling and heterogeneous metaphyseal lucencies in the distal radius, ulna, femur, and tibia. Genetic testing confirmed a mutation in the vacuolar protein sorting-associated protein 13B gene and a diagnosis of trapped neutrophil syndrome. Within 24 hr of initiating prednisone therapy (1 mg/kg, per os, q 12 hr), the dog was afebrile and nonpainful with normal ambulation. Lameness recurred twice over the next 5 mo. At 9 mo of age, diagnostics showed severe erosive polyarthritis of both stifles with an inflammatory leukogram and arthrocentesis findings consistent with septic arthritis, and the dog died despite antibiotic therapy. This is the first case of trapped neutrophil syndrome described in the North American literature, and it is unique in that we had the opportunity to document progression of radiographic abnormalities over more than 6 mo. Trapped neutrophil syndrome should be considered in young border collies with signs suggestive of immunemediated polyarthritis, septic arthritis, or hypertrophic osteodystrophy, combined with neutropenia or gastrointestinal signs. Read the full article

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