Hepatic insufficiency in two juvenile dogs with histoplasmosis.

A 9-month-old female intact toy poodle and a 1-year-old female intact Labrador retriever mix presented to separate teaching hospitals for chronic histories of malaise and clinicopathologic evidence of hepatic dysfunction. The signalment and clinical histories of these dogs prompted consideration of a congenital portosystemic shunt as a primary differential. However, microscopic evaluation of peritoneal effusion, pleural effusion, and peripheral blood samples from the dogs revealed round to ovoid yeast organisms morphologically most compatible with Histoplasma capsulatum. Additional testing confirmed histoplasmosis in each case. The poodle underwent a computed tomography (CT) study, which showed hepatomegaly with a spleno-gonadal shunt, pancreatic and gastric wall edema, and marked peritoneal effusion, findings compatible with portal hypertension and secondary acquired shunt formation. The dog was later humanely euthanized due to clinical deterioration, and on necropsy hepatic histoplasmosis was verified, with additional affected tissues comprising lungs and spleen. The Labrador Retriever mix responded clinically and clinicopathologically to antifungal therapy, though no abdominal imaging was performed to definitively exclude the possibility of a congenital portosystemic shunt. In retrospect, several features were more compatible with histoplasmosis than portosystemic shunt in these cases, including hyperbilirubinemia, effusion, and hepatomegaly. These findings serve as a reminder of the need to interpret serum biochemical findings in the context of the totality of the clinicopathologic data and imaging findings, as well as the diagnostic value of microscopy in the evaluation of hematologic and body cavity fluid samples.

Telangiectatic osteosarcoma in four dogs: Cytologic, histopathologic, cytochemical, and immunohistochemical findings.

Telangiectatic osteosarcoma is a rare variant of osteosarcoma histologically and clinically similar to hemangiosarcoma (HSA). This case series describes the imaging and cytologic features of four histologically confirmed telangiectatic osteosarcomas, including the use of cytochemical stains. Alkaline phosphatase (ALP) was applied to Wright-Giemsa-stained cytology slides, and Factor VIII immunohistochemistry was evaluated. Cytologic characteristics included atypical mesenchymal cells with evidence of acute and chronic hemorrhage. Telangiectatic osteosarcoma cases had positive ALP cytochemical staining, while control HSA cases were negative. Factor VIII immunohistochemistry was negative in telangiectatic osteosarcoma and positive in HSA. Cytologic diagnosis of telangiectatic osteosarcoma with positive ALP cytochemical staining can help differentiate this neoplasm from HSA.

Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

Retrospective evaluation of fluid production at the time of thoracostomy tube removal following elective and emergency surgery in dogs (2010-2017): 185 cases.

OBJECTIVE: To report the rate of fluid production at the time of removal of thoracostomy tubes placed intraoperatively and to determine the association of this rate with specific patient factors, surgical factors, or clinical diagnosis. The secondary objective was to determine whether identification of pleural effusion within 2 weeks of thoracostomy tube removal was associated with the same variables. DESIGN: Retrospective study. SETTING: University teaching hospital. ANIMALS: One hundred eighty-five client-owned dogs with thoracostomy tubes placed intraoperatively between January 2010 and March 2017. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thoracostomy tubes were removed at a median fluid production of 0.09 mL/kg/h (range, 0-7.0 m L/kg/h). Median fluid production at the time of thoracostomy tube removal was significantly higher in dogs with preoperative pleural effusion compared to dogs without preoperative pleural effusion (0.21 vs 0.05 mL/kg/h; P = 0.0001) and in dogs that had a median sternotomy compared to dogs that had a lateral thoracotomy (0.14 vs 0.09 mL/kg/h; P = 0.04). Of the 169 dogs available for follow-up, 12 (7.1%) had pleural effusion within 2 weeks of removal of the thoracostomy tube. Detection of pleural effusion during the follow-up period was significantly associated with the presence of preoperative pleural effusion (P = 0.0019) and the diagnosis (P = 0.01). A greater proportion of dogs with a lung lobe torsion (4/9, 44.4%) and idiopathic chylothorax (2/7, 28.5%) had pleural effusion within 2 weeks compared to other diagnoses. Reintervention was performed in 4.7% of dogs. CONCLUSIONS: Thoracostomy tubes were removed at pleural fluid production rates that frequently exceeded current veterinary guidelines. However, the fluid production rate at the time of thoracostomy tube removal was not associated with the detection of pleural effusion within 2 weeks of thoracostomy tube removal, and the overall need for reintervention following thoracostomy tube removal was low (4.7%).

Advances in the diagnosis of acute pancreatitis in dogs.

In the last 20 years, the diagnosis of pancreatitis has become more frequent as a result of improved diagnostic modalities such as abdominal ultrasound examination, advanced imaging, and immunoassays for the measurement of pancreatic lipase. Our aim is to provide a state-of-the-art overview of the clinical diagnosis of acute pancreatitis (AP) in dogs with a particular focus on pancreatic lipase assay validation and clinical performance, in addition to advanced imaging modalities. We also discuss the potential indications for cytology and histopathology in dogs with suspected AP.

Clinical ophthalmological diagnostic description of 10 healthy sugar gliders (Petaurus breviceps) and prevalence of ocular-related presentations in a larger hospital population.

OBJECTIVE: To provide reference values for ocular examination and diagnostics in ophthalmologically normal sugar gliders (Petaurus breviceps). To retrospectively determine the prevalence of ocular diseases in sugar gliders presenting to a single institution. ANIMALS: Ten client owned and 106 previously evaluated sugar gliders. PROCEDURE: A descriptive study evaluated sugar gliders presented to Colorado State University's Avian, Exotics, and Zoological Medicine Service (CSU-AEZ) from August-2019 to January-2020. A complete ophthalmic examination including Schirmer tear test II (STT II), phenol red threat test (PRTT), intraocular pressure (IOP) via rebound tonometry, fluorescein, and rose bengal stain was performed under anesthesia. Conjunctival aerobic culture swabs and cytology were collected prior to ophthalmic evaluation. A retrospective review of medical records of sugar gliders presented to CSU-AEZ from 2008 to 2018 for ocular disease was performed. RESULTS: Mean values ± standard deviation for selected diagnostics included the following: STT II: 2.2 ± 6.7 mm/min; PRTT: 0 ± 0 mm/15 s; IOP: 12 ± 2.6 mm Hg. Fluorescein and rose bengal staining highlighted corneal abrasions secondary to tear testing. The three most common conjunctival bacterial isolates cultured were Staphylococcus spp. (3/20, 15%), Coryneform spp. (3/20, 15%), and unidentified Gram-positive cocci (3/20, 15%). Retrospective analysis revealed ocular diseases to be the third most common abnormality resulting in sugar glider presentations (13/106, 12.3%). CONCLUSION: This descriptive study gives reference values for IOP, conjunctival microbiology, and cytology for sugar gliders. STT II and PRTT provide little clinical value in sugar gliders. The retrospective study revealed that ocular abnormalities, often secondary to dental disease, are a common reason for presentation.

Diagnosis of canine renal lymphoma by cytology and flow cytometry of the urine.

Lymphoma is a common hematopoietic neoplasm of dogs. A definitive diagnosis typically requires the collection of samples via fine-needle aspirate or biopsy. A unique case of canine renal T-cell lymphoma diagnosed using urine sediment microscopy with flow cytometry and PCR for Antigen Receptor Rearrangement (PARR) is presented. A fresh urine sample was collected via a urinary catheter and immediately prepared for cytologic examination, flow cytometry, and PARR. The flow cytometric study revealed that 83% of the cells were large CD3+ CD8+ T cells, while PARR identified a clonally rearranged T-cell receptor gene, supporting the flow cytometry findings. Despite supportive care, the patient progressed to anuric renal failure and was humanely euthanized. A necropsy was performed, and tissues from the upper and lower urinary tracts were collected. Histologically, the right and left kidneys were infiltrated by a neoplastic round cell population effacing the cortex and medulla. Immunohistochemistry for the T- and B-cell antigens CD3 and CD20, respectively, revealed that the neoplastic population within the kidney demonstrated diffuse, strong, membranous to intracytoplasmic CD3 expression while lacking CD20 expression. These results confirmed the diagnosis of renal T-cell lymphoma. This is the first known report of canine lymphoma diagnosed using either urine flow cytometry or clonality testing. Therefore, in select cases, urine flow cytometry and/or PARR are feasible to perform on urine-derived cells as a quick and cost-effective means to aid in the diagnosis of urinary tract lymphoma.

Bilateral Anterior Uveitis in a Northern Saw-whet Owl (Aegolius acadicus) With a Metastatic Pectoral Malignant Mesenchymoma.

A captive, adult, male northern saw-whet owl (Aegolius acadicus) was examined for blepharospasm of the left eye. The owl was diagnosed with bilateral anterior uveitis and a corneal ulceration in the left eye. It was treated with oral and topical nonsteroidal anti-inflammatory medications and a topical antibiotic. Multiple recheck examinations and medication adjustments were performed over the next 4 months, at the end of which time the bilateral anterior uveitis was controlled with a topical nonsteroidal anti-inflammatory applied 3 times per week to both eyes. The owl was re-examined 2 months later after 2 suspected neurologic episodes. On physical examination, the owl was quiet and had difficulty standing and ambulating. Five firm multilobular and immobile masses were identified overlying the pectoral muscle and sternum. Fine-needle aspiration from 1 mass revealed neoplastic cells consistent with a sarcoma. The owl was euthanatized. On the basis of results of histopathologic examination, the mass was diagnosed as a pleomorphic spindle cell sarcoma with features of rhabdomyosarcoma, liposarcoma, and osteosarcoma. Numerous tumor cells were immunopositive for myoglobin and desmin, indicating striated muscle origin. Although a metastatic lesion was present in 1 adrenal gland, lesions of inflammation or neoplasia were absent in either eye on histopathologic examination. This report describes an apparent ocular manifestation of systemic disease in an avian species with clinically diagnosed recurrent anterior uveitis.

Sexual dimorphism of acute doxorubicin-induced nephrotoxicity in C57Bl/6 mice.

Doxorubicin (DOX) is a chemotherapeutic agent that has been reported to cause nephrotoxicity in rodent models and to a lesser degree in cancer patients. Female rodents have been shown to be protected against several features of DOX-induced nephrotoxicity. Nevertheless, the underlying mechanisms of this sexual dimorphism are not fully elucidated. Therefore, in the current study, we investigated the sex and time-dependent changes in pathological lesions as well as apoptotic and fibrotic markers in response to acute DOX-induced nephrotoxicity. We also determined the effect of acute DOX treatment on the renal expression of the sexually dimorphic enzyme, soluble epoxide hydrolase (sEH), since inhibition of sEH has been shown to protect against DOX-induced nephrotoxicity. Acute DOX-induced nephrotoxicity was induced by a single intra-peritoneal injection of 20 mg/kg DOX to male and female adult C57Bl/6 mice. The kidneys were isolated 1, 3 and 6 days after DOX administration. Histopathology assessment, gene expression of the apoptotic marker, BAX, protein expression of the fibrotic marker, transforming growth factor-ß (TGF-ß), and gene and protein expression of sEH were assessed. DOX administration caused more severe pathological lesions as well as higher induction of the apoptotic and fibrotic markers in kidneys of male than in female mice. Intriguingly, DOX inhibited sEH protein expression in kidneys of male mice sacrificed at 3 and 6 days following administration, suggesting that induction of sEH is not necessary for acute DOX-induced nephrotoxicity. However, DOX-induced inhibition of renal sEH in male mice may protect the kidney from further DOX-induced injury in a negative feedback mechanism. We also observed lower constitutive expressions of TGF-ß and sEH in the kidney of female mice which may contribute, at least in part, to sexual dimorphism of DOX-induced nephrotoxicity.

Retrospective characterization of canine coagulopathies using the turbidimetric ACL-TOP 300 analyzer (2014-2015): Forty-seven dogs.

OBJECTIVE: To characterize disseminated intravascular coagulation (DIC), liver failure (LF), post-hepatic cholestasis (PHC), and anticoagulant rodenticide intoxication (ROD) in dogs using an immunoturbidimetric coagulation analyzer and to characterize the relationship between clinical bleeding and bleeding parameters. DESIGN: Retrospective study (August 2014-July 2015). SETTING: University teaching hospital. ANIMALS: Forty-seven client-owned dogs diagnosed with DIC (n = 24), LF (n = 9), PHC (n = 5), or ROD (n = 9) based on history, clinical pathology, cytology, histopathology. or exploratory surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Median prothrombin time (PT), activated partial thromboplastin time (aPTT), and quantitative fribrinogen assay (QFA) were above the reference interval for DIC, LF, PHC and ROD with the exception of a normal QFA for LF. Clot curve analysis for DIC was characterized by elevated PT Delta, PT first derivative, and aPTT Delta, and normal for aPTT second derivative; all LF parameters were within the RI; all PHC parameters were above the RI; and ROD had elevated aPTT delta, but low aPTT second derivative. Coagulopathic bleeding recognized within the DIC group was characterized by median PT delta in mABS (milliabsorbance), first derivative and aPTT delta values in mABS within the RI at 35.0, 55.5 and 38, respectively. The nonbleeding DIC group median values of these same parameters were 189.5, 586.5 and 288, respectively. CONCLUSIONS: The classically utilized indicators of secondary hemostasis, PT and aPTT, were prolonged within all 4 groups; DIC, LF, PHC and ROD as expected. Fibrinogen concentration was increased in both PHC and ROD, decreased in LF and increased but with a bimodal distribution in DIC that correlated with clinical bleeding. The degree of PT and aPTT prolongation did not correlate with clinical bleeding in the DIC group, however clot curve analysis, did reveal an association.

Observational Study Design in Veterinary Pathology, Part 2: Methodology.

Observational studies are a basis for much of our knowledge of veterinary pathology, yet considerations for conducting pathology-based observational studies are not readily available. In part 1 of this series, we offered advice on planning and carrying out an observational study. Part 2 of the series focuses on methodology. Our general recommendations are to consider using already-validated methods, published guidelines, data from primary sources, and quantitative analyses. We discuss 3 common methods in pathology research-histopathologic scoring, immunohistochemistry, and polymerase chain reaction-to illustrate principles of method validation. Some aspects of quality control include use of clear objective grading criteria, validation of key reagents, assessing sample quality, determining specificity and sensitivity, use of technical and biologic negative and positive controls, blinding of investigators, approaches to minimizing operator-dependent variation, measuring technical variation, and consistency in analysis of the different study groups. We close by discussing approaches to increasing the rigor of observational studies by corroborating results with complementary methods, using sufficiently large numbers of study subjects, consideration of the data in light of similar published studies, replicating the results in a second study population, and critical analysis of the study findings.

Retrospective comparison of standard clotting tests and novel clot waveform parameters in dogs using the turbidimetric ACL-TOP CTS 300 coagulation analyzer.

Clot waveforms are generated by coagulation analyzers, such as the ACL-TOP, that utilize photo-optical turbidimetric methods to measure prothrombin time (PT) and activated partial thromboplastin time (aPTT), which are standard clotting tests (SCTs). Additional quantitative clot waveform analysis (CWA) parameters include maximum velocity of the PT curve (PT1d), maximum acceleration of the aPTT curve (aPTT2d), and their change in optical density (ODdelta). We explored the potential for CWA to contribute unique information compared to SCTs and quantitative fibrinogen assay (QFA) in dogs with clinical indications for laboratory evaluation of coagulation. We retrospectively evaluated the frequency and agreement between normal, high, and low values of CWA and SCTs for 203 dogs relative to reference intervals (RIs). Most dogs had SCTs within RIs, but most CWA values were high regardless of whether SCT values were within, below, or above the RI. Agreement between SCTs and CWA was slight (kappa <30%). Clinically significant bleeding was noted in 28 of 203 (14%) dogs. SCTs were not different between bleeders and non-bleeders. Median QFA, PT1d, aPTTdelta, and aPTT2d values were statistically significantly higher than RIs in non-bleeders compared to bleeders, whose median values were not below RI. Compared with SCTs, CWA identified differences between the 2 groups. However, wide overlap between the 2 groups limits the use of CWA to clinically discriminate between bleeders and non-bleeders in a heterogeneous population of dogs. Further studies on the diagnostic utility of CWA in coagulopathic dogs are needed.