Table of Contents and AbstractsAugust 2021, Vol. 62, No. 8
All in the family: A comparative look at coronaviruses
John Ellis (page 825)
Coronaviruses, members of the order Nidovirales, the largest and most complex of the positive-stranded RNA viruses, have been recognized as important causes of disease in veterinary medicine for nearly a century. In contrast, in human medicine, especially until the recent SARS-CoV-2 pandemic, they were unimportant viruses associated with the common cold. This is a brief comparative review of the biology of coronaviral infections emphasizing the commonalities among the various members of the family and considering how the veterinary experience with coronaviruses can inform the response to SARS-CoV-2. Coronaviruses are perhaps best viewed as mutation machines whose genetic sequences can readily change through genetic drift, recombination, and deletions from a large genome. However, to be of clinical concern, variants must have the perfect set of amino acids in the S protein receptor binding domain and in their replication-mediating nonstructural proteins. Extensive experience with veterinary coronaviral vaccines suggests that optimal clinical immunity is a tandem of mucosal and systemic responses induced by a combination of mucosal and parenteral vaccines.
Cryotherapy provides transient analgesia in an induced lameness model in horses
Vivian Quam, Jonathan Yardley, Mikkel Quam, Cahuê Paz, James Belknap (page 834)
The analgesic effect of cryotherapy in an induced lameness model was evaluated. Lameness was induced with solar pressure from a custom-made shoe in a 10-horse, cross-over study. The degree of lameness was recorded with a commercial non-invasive inertial sensor. The distal limbs were maintained in an ice and water slurry (cryotherapy) or at ambient temperature (control) for 1 hour. Lameness was assessed serially over the following hour. Lameness at each time point was compared to the baseline induced lameness, within and between groups. Lameness had improved significantly in all horses 5 minutes after treatment but remained improved 10 minutes after treatment for the cryotherapy group only. Fifteen minutes after treatment, lameness in the cryotherapy group was improved relative to the control. Cryotherapy produced moderate, transient analgesia. Additional research is required to determine if altering the method, duration, or temperature of cryotherapy, as well as the targeted pathology and anatomy, alters the analgesic effect.
Indications and outcomes for puppies undergoing mechanical ventilation: 59 cases (2006 to 2020)
Elyzabeth Lemieux, Elizabeth Rozanski, Gareth Buckley, Nolan Chalifoux, Christopher Kennedy, Alex Lynch, Chrissie Rutter, Alyx Tracy, Deborah C. Silverstein (page 839)
The medical records of 59 puppies from 6 hospitals undergoing mechanical ventilation (MV) between 2006 and 2020 were reviewed to describe the signalment, underlying disease, duration of ventilation, and outcome. The most common underlying diseases were pneumonia (n = 18), non-cardiogenic pulmonary edema (n = 16), and trauma (n = 8). Twenty-six (44%) puppies were weaned from the ventilator. The overall survival rate was 39% (23/59) including 19 non-brachycephalic dogs and 4 brachycephalics. Median duration of mechanical ventilation was 27 hours (range: 4 to 144 hours). Brachycephalic dogs were less likely to survive than non-brachycephalic dogs (P = 0.032). English bulldogs were over-represented with pneumonia. No association between age and survival to discharge (P = 0.716) or outcome (P = 0.579) was detected. The survival rate, and underlying disease process and severity for mechanically ventilated puppies was similar to previous studies in adult dogs.
Obstipation in pet pigs: 24 cases
Kallie J. Hobbs, SallyAnne L. DeNotta, Aitor Gallastegui, George L. Elane, Luis A. Rivero, Pamela Adkins, Diego E. Gomez (page 843)
Clinical features and patient outcomes for pet pigs with obstipation are poorly defined. This retrospective study reports the clinical findings from 24 pet (non-production) pigs with obstipation presented to 2 veterinary teaching hospitals. Clinical features of obstipated pet pigs included anorexia or hyporexia in 24 pigs (100%), pain on abdominal palpation in 22 (90%), lethargy in 21 (88%), tachypnea in 19 (79%), vomiting in 14 (58%), and tachycardia in 13 (54%). Frequently observed hematologic and biochemical abnormalities included leukopenia in 36% (8/22) of the pigs, lymphopenia in 75% (17/22), toxic changes in neutrophils in 63% (14/22), hypokalemia in 50% (9/18), and hypoglycemia in 28% (5/18). Diagnostic imaging via radiography and/or computed tomography frequently identified gastric distention and accumulation of ingesta and gas throughout the gastrointestinal tract. Medical treatments included fluid therapy, anti-emetics, oral administration of carbonated beverages, non-steroidal anti-inflammatory drugs, and systemic antimicrobials. Surgical intervention was performed in 7/29% of pigs. In this study, obstipation in pet pigs carried a fair to favorable prognosis for survival, with 70% of patients surviving to discharge.
Multiple myeloma and primary erythrocytosis in a dog
Marianna Ricci, Giulia De Feo, Martin Konar, George Lubas (page 849)
A 13-year-old spayed female mixed breed dog was referred for impaired ambulation, limb tremors, back pain, hypergammaglobulinemia on cellulose acetate electrophoresis, and mild proteinuria. Conventional radiology and magnetic resonance imaging (MRI) suggested multifocal neoplastic bone lesions. At the referral examination, lameness and bright red mucous membranes were observed. Severe erythrocytosis, a monoclonal peak in the β-2 globulin detected by capillary zone electrophoresis, severe proteinuria, bone marrow infiltration of plasma cells, and low serum erythropoietin concentrations were reported. The final diagnosis was multiple myeloma associated with severe primary erythrocytosis. This presentation in a dog is interesting because the combination of both disorders is rare in humans and has not been reported in dogs.
Key clinical message: Although rare, multiple myeloma and primary erythrocytosis can occur together in dogs.
Subcutaneous and cardiopulmonary dirofilariasis in a dog
Leticia B. Oliveira, Brittany J. McHale, Guilherme G. Verocai, Daniel R. Rissi (page 854)
Canine subcutaneous dirofilariasis is rare and typically caused by Dirofilaria repens. An adult male, intact, mixed breed dog from South Carolina, USA, was examined because of physical trauma to the right maxilla. The dog died during hospitalization and was submitted for necropsy. Gross post-mortem changes included approximately 150 adult nematodes morphologically consistent with Dirofilaria spp. in the pulmonary artery, right atrium, and right ventricle. Histologically there was widespread proliferative pulmonary endarteritis with intraluminal nematodes morphologically consistent with Dirofilaria spp. Four similar nematodes were present in the subcutaneous tissue of the left medial thigh and tibial area. These nematodes were located within the fascia and skeletal muscles. They were surrounded by epithelioid macrophages and multinucleated giant cells, with some lymphocytes and plasma cells, and areas of mineralization (interpreted as mineralized cross sections of nematodes). Nematodes were morphologically identified as D. immitis. Subcutaneous dirofilariasis caused by D. immitis occurs when migrating nematode larvae develop into adults in the subcutaneous and skeletal muscle tissues.
Key clinical message: Subcutaneous dirofilariasis in dogs is rare and most often associated with Dirofilaria repens. This case highlights the pathology findings of subcutaneous D. immitis in a dog.
Intramuscular Grade 1 fibrosarcoma: Magnetic resonance imaging findings in 2 dogs
Karine P. Gendron, Elizabeth W. Howerth, Koichi Nagata, Michael Perlini, Nicole Northrup (page 857)
Two adult neutered male dogs were presented for evaluation of firm, painless masses arising within muscle: an 8-year-old German wirehaired pointer dog with an accessory tricipital growth, and a 3-year-old German shepherd dog with a gracilis muscle growth. Magnetic resonance imaging (MRI) characteristics suggested malignant behavior, with a central fluid-like portion with a hyperenhancing lining, a nidus of disorganized tissue, and an extensive reactive zone, whereas histopathology was consistent with low-grade fibrosarcoma. This report describes histologically low-grade, yet biologically high-grade intramuscular fibrosarcoma, in which MRI provided detailed information on tumor behavior and assisted with biopsy and surgical planning.
Medial malleolus fragmentation following talocalcaneal arthrodesis by a dorsomedial approach in a horse
Pablo Espinosa-Mur, Mathieu Spriet, Marcos Perez Nogues, Thomas Cullen, Larry D. Galuppo (page 861)
A 16-year-old, Quarter Horse mare was presented for a 3/5 right hind lameness associated with osteoarthritis of the talocalcaneal joint (TCLJ). Positron emission tomography (PET) and computed tomography (CT) demonstrated marked increased uptake of 18F-sodium fluoride and bone remodeling at the medial facet of the TCLJ, respectively. Under general anesthesia 2 cortical screws (4.5 and 5.5 mm) were placed in neutral fashion via an arthrotomy from dorsomedial to plantaromedial through the medial facet of the TCLJ followed by copious lavage of the tarsocrural joint. Eight weeks after surgery, observable effusion of the tarsocrural joint was present and lameness had worsened. Radiographic examination revealed a fragmented medial malleolus of the tibia, likely secondary to repetitive trauma of the screw heads during tarsal flexion. Repeated CT showed partial fusion of the TCLJ. Both screws were removed and the tarsocrural joint was thoroughly lavaged arthroscopically. At a 20-month recheck the lameness had not improved, and ultrasound examination revealed severe thickening of the TCLJ capsule. Recheck examination 48 mo after surgery showed complete fusion of the TCLJ and resolution of the lameness.
Key clinical message: Diagnosis of osteoarthritis of the TCLJ is challenging. Management by arthrodesis using a dorsomedial approach can result in fragmentation of the medial malleolus, with secondary synovitis and capsulitis of the tarsocrural joint.
Fungal osteitis of the axial aspect of the mid body of the medial proximal sesamoid bone in a horse
Alejandro Merchán, Jana K. Voss, Marie-Soleil Dubois (page 867)
The satisfactory outcome of fungal osteitis in an 8-year-old American Quarter Horse is described. The horse was admitted with a grade 4 out of 5 lameness and exhibited metacarpophalangeal synovial effusion, indicative of a mild suppurative inflammation. Results of initial radiographic and ultrasonographic examination were unremarkable. Intra-articular anesthesia of the metacarpophalangeal joint allowed localization of the insult. It was not until day 6 of hospitalization when lytic changes on the axial aspect were observed on radiographic examination. Arthroscopic examination permitted identification and debridement of the affected bone. Fungal culture of the bone yielded Pleosporales spp. The horse was sound at the time of discharge after 12 days of hospitalization. No complications occurred in the post-operative period and the horse resumed his initial level of activity and competition in barrel racing.
Key clinical message: To our knowledge, this is the first description of successful outcome of a fungal osteitis of the sesamoid bones following arthroscopic debridement. We hypothesize that the satisfactory outcome is associated with early recognition of the condition and aggressive debridement of the lesion arthroscopically.
Surgical treatment of a double aortic arch in a dog
Maya Sekhar, Katherine Meyers, Susan W. Volk, David E. Holt (page 872)
An 8-month-old spayed female Labrador retriever dog was evaluated for regurgitation 6 months after surgery for a suspected vascular ring anomaly. The dog had a history of regurgitation and slow development as a puppy. An initial left-sided exploratory thoracotomy was unsuccessful in identifying and treating a vascular ring anomaly. The dog was subsequently presented to the PennVet Emergency Service for regurgitation. Thoracic radiography showed cranial thoracic esophageal dilation and an esophageal foreign body that was then removed endoscopically. Subsequent computed tomographic (CT) angiography revealed a double aortic arch. A left 4th intercostal space thoracotomy was performed. The smaller left aortic arch and a left ligamentum arteriosum were ligated and transected. The dog recovered uneventfully and was healthy at the 1-month follow-up visit. This is the 5th reported successful surgical correction of a double aortic arch in a dog. Computed tomographic angiography was essential in diagnosis and surgical planning.
Key clinical message: Although uncommon, double aortic arches can occur and present a diagnostic and surgical challenge when a persistent right aortic arch is suspected. Computed tomographic angiography provides an accurate preoperative diagnosis and allows for surgical planning.
Hematuria in a 3-month-old filly with an internal umbilical abscess and internal iliac artery aneurysm
Luiza Zakia, Sarah Shaw, Natacha Bonomelli, Siobhan O’Sullivan, Alex zur Linden, Marie Dubois, John Baird, Bruce Guest (page 877)
A 3-month-old foal with a history of acute hematuria was evaluated. Hydronephrosis and hydroureter were visualized upon renal ultrasonography of the left kidney. Cystoscopy identified a blood clot occluding the left ureter. Computed tomography (CT) revealed a large retroperitoneal abscess at the level of the aortic bifurcation and a left internal iliac aneurysm. Due to the severity of the lesions and the poor prognosis, the filly was euthanized and the clinical findings were confirmed by post-mortem examination. This report emphasizes the value of obtaining a precise diagnosis via CT in order to avoid unviable treatment approaches when confronted with this unusual secondary complication of omphaloarteritis.
Key clinical message: Umbilical complications are routinely diagnosed in equine neonatal medicine, and commonly lead to septicemia, physitis, and septic arthritis; severe internal umbilical abscessation, and subsequent vascular and urinary disorders are uncommon sequelae.
How is our profession doing?
John Kastelic, Tim Ogilvie (page 801)
VETERINARY MEDICAL ETHICS
Heather Broughton, Sophie Perreault (page 811)
The origins and lineage of One Health, Part I
Justin Ancheta, Raad Fadaak, R. Michele Anholt, Danielle Julien, Herman W. Barkema, Myles Leslie (page 883)
INDEX OF ADVERTISERS