Evaluation of feline heartworm disease based on gross necropsy, serology, pulmonary histopathology, and radiographic evidence in adult shelter cats in northeastern Alabama.

BACKGROUND: Veterinary knowledge regarding feline heartworm has been increasing significantly over the past two decades. Necropsy surveys of shelter cats have shown feline adult heartworm infection prevalence to be 5-20% of the rate in unprotected dogs; however, other studies have shown feline heartworm antibody prevalence up to 33%, reflecting higher exposure rates and potential immature adult infections. Thus, the true prevalence of feline heartworm infection is likely underestimated due to the limitations of current diagnostic techniques, inadequate testing protocols, and the high likelihood of cats exhibiting transient clinical signs or dying without confirmation of infection. Diagnosing Feline Heartworm Disease (FHWD), also referred to as Heartworm Associated Respiratory Disease (HARD), is one of the conundrums of veterinary medicine. The purpose of this study was to evaluate and characterize the occurrence of Heartworm Associated Respiratory Disease [HARD] in shelter cats, naturally-infected with D.immitis. METHODS: Fifty shelter cats slated for euthanasia between December 2009 and June 2010 were investigated by gross necropsy, radiography, serology, and lung histopathology using techniques that have been established in experimental models of cat heartworm infection. The relationship between pulmonary vascular disease and serological markers for heartworm was also examined using correlations and statistical modeling. Serology included standard heartworm antigen test and a commonly used heartworm antibody test. Also included were heat-treated heartworm antigen test and two additional heartworm antibody tests previously evaluated on experimentally-infected cats. RESULTS: None of the cats were heartworm antibody (HW Ab) positive on a commonly used HW Ab test used by many reference laboratories even though 20% of the study cats were heartworm antigen (HW Ag) positive on heat-treated samples. Two additional HW Ab test were positive on 26% and 22% of the study cats. The combination of heat-treated HW Ag, HW Ab tests, and histopathology indicated 34% of the study cats had HARD. CONCLUSIONS: Utilizing both, the above tests, and thoracic radiographs, enhanced the ability to predict vascular disease, possibly caused by infection with immature and adult heartworms and supported the premise that cats develop heartworm disease at the same rate as dogs.

Minimally invasive splenectomy is associated with a low perioperative complication rate and short operative time in cats.

OBJECTIVE: To report the perioperative outcome and complications in cats undergoing minimally invasive splenectomy. ANIMALS: 17 client-owned cats. METHODS: Perioperative data were collected from cats undergoing minimally invasive splenectomy from September 2010 to June 2023. Data included history, signalment, preoperative examination and diagnostic testing results, operative technique and time, perioperative outcomes, complications, hospitalization duration, histopathological diagnosis, and outcome. RESULTS: 13 spayed females and 4 neutered males were included, with a median age of 144 months (48 to 196 months). Seven cats underwent total laparoscopic splenectomy (TLS), with 1 cat requiring conversion from TLS to laparoscopic-assisted splenectomy (LAS) due to splenomegaly and an additional cat requiring conversion from TLS to open splenectomy due to uncontrollable splenic capsular hemorrhage. Ten cats underwent LAS, with 1 cat requiring conversion to open splenectomy due to splenomegaly. Additional procedures were performed in 13 cats, with the most common being liver biopsy in 10 cats. Median operative times were 50 minutes (45 to 90 minutes) for TLS and 35 minutes (25 to 80 minutes) for LAS. An intraoperative complication occurred in 1 cat. All but 1 cat survived to discharge. Median follow-up time was 234 days (18 to 1,761 days), with 15 of 16 cats confirmed alive at 30 days and 9 of 16 cats alive at 180 days postoperatively. CLINICAL RELEVANCE: Minimally invasive splenectomy in this cohort of cats was associated with short operative times and a low perioperative complication rate. Veterinary surgeons may consider minimally invasive splenectomy as an efficient and feasible technique in the treatment of splenomegaly or modestly sized splenic masses for diagnostic and therapeutic purposes in cats.

Presumed mediastinal cysts have a low prevalence in canine thoracic computed tomographic studies.

Mediastinal cysts (MCs) are rare lesions that can arise from embryonic remnants of various mediastinal structures. MCs usually are incidental findings in dogs and cats; however, they can reach a mass-like appearance. The description of MCs on CT in dogs is limited. This retrospective, single-center, descriptive, prevalence study aimed to determine the prevalence of presumed mediastinal cysts (PMCs) in dogs and assess their CT characteristics. Dogs that underwent a thoracic CT scan from January 2019 to August 2021 were included. CT images were evaluated for the presence of PMCs by two diagnostic imaging interns, two last year diagnostic imaging residents, and a board-certified veterinary radiologist. Number, location, margins, shape, volume, size, mass effect, and attenuation values of PMCs were assessed. A total of 866 CT scans were reviewed, and 49 PMCs were identified. The prevalence of PMCs in dogs was 5.66%. English Bulldog and mixed-breed dogs were subjectively overrepresented; however, the possibility of population bias could not be excluded. PMCs were subjectively more frequently observed in male dogs. The PMCs were predominantly round, small, solitary fluid-filled findings localized in the cranioventral mediastinum, with well-defined margins, homogeneous attenuation, and no contrast enhancement. The median attenuation value was 6.32 HU (range: -20.16 to 23.45 HU) precontrast and 7.58 HU (range: -2.45 to 20.79 HU) postcontrast, and the median volume was 1.19 cm3 (range: 0.02-45.32 cm3). Although the prevalence of PMCs was low in our sample population, findings supported prioritizing a differential diagnosis of incidental PMC for dogs with the above imaging characteristics.

Diagnostic immunohistochemistry of primary and secondary central nervous system neoplasms of dogs and cats.

The diagnosis of primary and secondary CNS neoplasms of dogs and cats relies on histologic examination of autopsy or biopsy samples. In addition, many neoplasms must be further characterized by immunohistochemistry (IHC) for a more refined diagnosis in specific cases. Given the many investigations assessing the diagnostic and prognostic IHC profile of CNS neoplasms in the veterinary literature, it may be difficult for the diagnostic pathologist or pathology trainee to narrow the list of reliable diagnostic IHCs when facing a challenging case. Here we compile a comprehensive list of the most diagnostically relevant immunomarkers that should be utilized for the diagnostic support or confirmation of the most common primary and secondary CNS neoplasms of dogs and cats.

No viable bacterial communities reside in the urinary bladder of cats with feline idiopathic cystitis.

Urinary microbial diversities have been reported in humans according to sex, age and clinical status, including painful bladder syndrome/interstitial cystitis (PBS/IC). To date, the role of the urinary microbiome in the pathogenesis of PBS/IC is debated. Feline idiopathic cystitis (FIC) is a chronic lower urinary tract disorder affecting cats with similarities to PBS/IC in women and represents an important problem in veterinary medicine as its aetiology is currently unknown. In this study, the presence of a bacterial community residing in the urinary bladder of cats with a diagnosis of FIC was investigated. Nineteen cats with clinical signs and history of FIC and without growing bacteria in standard urine culture were included and urine collected with ultrasound-guided cystocentesis. Bacterial community was investigated using a culture-dependent approach consisted of expanded quantitative urine culture techniques and a culture-independent approach consisted of 16S rRNA NGS. Several methodological practices were adopted to both avoid and detect any contamination or bias introduced by means of urine collection and processing which could be relevant due to the low microbial biomass environment of the bladder and urinary tract, including negative controls analysis. All the cats included showed no growing bacteria in the urine analysed. Although few reads were originated using 16S rRNA NGS, a comparable pattern was observed between urine samples and negative controls, and no taxa were confidently classified as non-contaminant. The results obtained suggest the absence of viable bacteria and of bacterial DNA of urinary origin in the urinary bladder of cats with FIC.

Dilated pore of Winer in a dog.

A 9-year-old male neutered Goldendoodle was presented to the Animal Medical Center of Seattle with a history of a firm, hairless, cystic mass on the dorsal aspect of the neck. The mass had been present for 2 years and would periodically rupture and discharge moderate quantities of yellow-green, soft, semi-solid, keratinaceous material. As rupture of the mass was reported to cause the patient significant pain and discomfort, it was surgically excised. Histopathology of the mass revealed a bulbous keratin-filled cyst that communicated with the external environment via a small ostium. At the base of the cyst, the cyst lining was characterized by a markedly irregular and hyperplastic stratified squamous epithelium with an overt stratum granulosum and prominent, irregularly sized, shaped and spaced rete ridges. At the superficial aspect of the cyst near the ostium, the cystic lining was characterized by a relatively thinner stratified squamous epithelium with an overt stratum granulosum and regular basal contour. Based on the histomorphological appearance of the mass, a diagnosis of a dilated pore of Winer was made. Dilated pores of Winer are follicular cysts arising from the infundibulum of the hair follicle. They are relatively common in humans and uncommon in cats, and single case reports have been described in a horse and a woodchuck (Marmota monax). To the best of the authors' knowledge, this is the first description of a dilated pore of Winer in a dog.

Fluoroscopy-guided fine-needle aspiration of deep-seated pulmonary masses in dogs and cats appears safe and accurate.

OBJECTIVE: Deep-seated pulmonary lesions can be difficult to sample safely. The objective of this study was to determine the relative safety and accuracy of fluoroscopy-guided fine-needle aspiration of deep-seated pulmonary lesions regardless of their size and depth. ANIMALS: Client-owned animals; 5 dogs and 5 cats. CLINICAL PRESENTATION: Pulmonary lesion locations were determined on dorsoventral and lateral views using fluoroscopy. The lateral thoracic wall was aseptically scrubbed, and an indelible marker was used to mark the point of entry of the needle for sampling. The path of a 22-gauge needle attached to a syringe was followed using fluoroscopic guidance. Mass volume (Vma) and distance from skin and pleura to lesion (DSK-L and DPL-L) were recorded. RESULTS: In dogs, mean Vma was 137.2 cm3 (range, 6.3 to 426.2 cm3). Mean DSK-L was 71 mm (range, 37 to 101 mm) and DPL-L was 33 mm (range, 16 to 71 mm). Exfoliative cytology results were consistent with carcinoma in 4 dogs and lymphoma in 1 dog. A minor postprocedural complication was noted in 1 dog. In cats, the mean Vma was 2.4 cm3 (range, 1.6 to 3.7 cm3). Mean DSK-L was 42 mm (range, 20 to 75 mm) and DPL-L was 21 mm (range, 12 to 32 mm). Cytology results were consistent with pulmonary carcinoma in 2 cats, inflammation in 2 cats, and necrotic debris in 1 cat. CLINICAL RELEVANCE: Fluoroscopy-guided fine-needle aspiration of pulmonary masses is a safe and accurate technique to obtain cytologic samples irrespective of the size and depth of the lesions.

Histologic characterization of the major duodenal papilla and association with concurrent biliary, pancreatic, and intestinal pathology in cats.

Conjoining of the major pancreatic duct and common bile duct at the major duodenal papilla (MDP) is suspected to predispose cats to the clinical syndrome of "triaditis." However, microanatomy of the MDP or presence of lesions at the MDP has not been assessed in cats with or without triaditis. The aims of this study were to characterize feline MDP histomorphology and to identify associations between MDP anatomy/disease and the presence of biliary, pancreatic, or intestinal inflammation or neoplasia. Histologic assessment was prospectively performed on the MDP, duodenum, jejunum, ileum, liver, and pancreas from 124 client-owned cats undergoing postmortem examination. The majority of cats (104/124, 84%) had a complex ductular network at the MDP, with no distinction between pancreatic and common bile ducts. Lymphoid aggregates at the MDP were common (63/124, 51%). Inflammation of the MDP (MDPitis) was present in 35 of 124 cats (28%) and was often concurrent with cholangitis, pancreatitis, or enteritis (32/35, 91%), but was only associated with enteritis (19/35, 54%, P < .05). Triaditis was less common (19/124, 15%), but was associated with both conjoined MDP anatomy (19/19, 100%, P < .05) and MDPitis (12/19, 63%, P < .05). Neoplasia was present in 37 of 124 cats (29%), with lymphoma (28/37, 78%) predominating. Enteropathy-associated T-cell lymphoma type 2 (EATL2) was most common (n = 16/37, 43%) and was associated with triaditis and MDPitis (P < .05). These findings suggest that anatomy, immune activation, and/or inflammation of the MDP may play a role in the pathogenesis of triaditis. Further studies are needed to elucidate the relationships between triaditis, MDPitis, and EATL2.

Renal amyloid-A amyloidosis in cats: Characterization of proteinuria and biomarker discovery, and associations with kidney histology.

BACKGROUND: Amyloid A (AA) amyloidosis is a protein misfolding disease arising from serum amyloid A (SAA). Systemic AA amyloidosis recently was shown to have a high prevalence in shelter cats in Italy and was associated with azotemia and proteinuria. OBJECTIVES: Investigate urine protein profiles and diagnostic biomarkers in cats with renal AA amyloidosis. ANIMALS: Twenty-nine shelter cats. METHODS: Case-control study. Cats with renal proteinuria that died or were euthanized between 2018 and 2021 with available necropsy kidney, liver and spleen samples, and with surplus urine collected within 30 days before death, were included. Histology was used to characterize renal damage and amyloid amount and distribution; immunohistochemistry was used to confirm AA amyloidosis. Urine protein-to-creatinine (UPC) and urine amyloid A-to-creatinine (UAAC) ratios were calculated, and sodium dodecyl sulfate-agarose gel electrophoresis (SDS-AGE) and liquid chromatography-mass spectrometry (LC-MS) of proteins were performed. RESULTS: Twenty-nine cats were included. Nineteen had AA amyloidosis with renal involvement. Cats with AA amyloidosis had a higher UPC (median, 3.9; range, 0.6-12.7 vs 1.5; 0.6-3.1; P = .03) and UAAC ratios (median, 7.18 × 10-3 ; range, 23 × 10-3 -21.29 × 10-3 vs 1.26 × 10-3 ; 0.21 × 10-3 -6.33 × 10-3 ; P = .04) than unaffected cats. The SDS-AGE identified mixed-type proteinuria in 89.4% of cats with AA amyloidosis and in 55.6% without AA amyloidosis (P = .57). The LC-MS identified 63 potential biomarkers associated with AA amyloidosis (P < .05). Among these, urine apolipoprotein C-III was higher in cats with AA amyloidosis (median, 1.38 × 107 ; range, 1.85 × 105 -5.29 × 107 vs 1.76 × 106 ; 0.0 × 100 -1.38 × 107 ; P = .01). In the kidney, AA-amyloidosis was associated with glomerulosclerosis (P = .02) and interstitial fibrosis (P = .05). CONCLUSIONS AND CLINICAL IMPORTANCE: Renal AA amyloidosis is associated with kidney lesions, increased proteinuria and increased urine excretion of SAA in shelter cats. Additional studies are needed to characterize the role of lipid transport proteins in the urine of affected cats.

Brain magnetic resonance imaging and computed tomography findings in cats and dogs with central nervous system cryptococcosis in Australia: 23 cases (2009-2020).

OBJECTIVE: To describe the imaging findings in Australian cats and dogs with CNS cryptococcosis. ANIMALS: 23 cases (10 cats; 13 dogs) with CNS cryptococcosis and brain MRI or CT studies available to review. METHODS: Retrospective, multi-institutional case series. Brain MRI or CT studies were reviewed by a board-certified radiologist. Imaging findings were described and the differences between cats and dogs explored. RESULTS: Morphologic features were consistent with extra-axial lesions in all (n = 13) dogs and either intra-axial (5/10) or extra-axial (4/10) lesions in cats, with 1 cat having no detectable lesions in low-field brain MRI scans. Meningeal abnormalities were most common, followed by forebrain and cerebellar lesions. Intracranial MRI lesions were typically T2 hyperintense and T1 hypo- to isointense. Four cases had T2 hypointense lesions affecting the brain, sinonasal cavity, or regional lymph nodes. Intracranial CT lesions were mostly soft tissue attenuating. Contrast enhancement was present in all cases with contrast series available, with ring enhancement shown only in cats. Osteolysis was more common in dogs than cats, particularly affecting the cribriform plate. All 13 dogs and many (6/10) cats had at least 1 lesion affecting sinonasal or contiguous tissues, and locoregional lymphadenomegaly was common (7/10 cats; 11/13 dogs). CLINICAL RELEVANCE: Imaging lesions in cryptococcal meningoencephalitis were extra-axial in dogs but could be intra-axial or extra-axial in cats. Careful examination for extracranial lesions (sinonasal, retrobulbar, facial soft tissue, tympanic bullae, or locoregional lymph nodes) is important to provide alternative safe biopsy sites. T2 hypointense lesions, while rare, should prompt consideration of cryptococcosis.

Skin Disease and Behavior Changes in the Cat.

The health of the skin and coat of a cat is connected to the behavioral health of the animal. Stressed animals can cause lesions to their skin and coat such as alopecia, ulcers, and self-mutilation. On the other hand, localized or systemic health problems can cause stress, or pain, and therefore can increase overgrooming and poor skin health. When treating overgrooming and related skin lesions, all the physical and behavioral causes must be addressed through a multimodal approach.

[Cytologic evidence of hepatocytotropic T-cell-lymphoma in a 15-year-old male cat]. / Zytologischer Nachweis eines hepatozytotropen T-Zell-Lymphoms bei einem 15 Jahre alten Kater.

This case report describes the rare phenomenon of emperipolesis-like invasion of lymphatic blasts into the hepatocytes of a 15-year-old European Shorthair cat. The cat presented with nonspecific clinical signs (inappetence and weight loss). Cytologic examination of an ultrasound-guided fine-needle aspirate of the liver showed a subset of hepatocytes with emperipolesis-like invasion by lymphatic blasts. Few extracellularly located lymphatic blasts exhibited erythrophagia. Following the cytological diagnosis of large cell lymphoma and 2 weeks of monotherapy with prednisolone, the patient was euthanized due to his poor general condition. A post-mortem sample was obtained from the liver to confirm the suspected cytological diagnosis of hepatocytotropic lymphoma. Histopathology subsequently confirmed the cytologic findings. Immunohistochemically, the lymphatic blasts were positive for CD3 leading to a diagnosis of hepatocytotropic T-cell-lymphoma, which has rarely been described so far.

Decreased circulating transforming growth factor-beta (TGF-ß) and kidney TGF-ß immunoreactivity predict renal disease in cats with naturally occurring chronic kidney disease.

OBJECTIVES: The aim of the present study was to compare the circulating transforming growth factor-beta (TGF-ß) of clinically normal age-matched and naturally occurring chronic kidney disease (CKD) cats and to determine the correlation between the TGF-ß expression and histopathological changes in cats with CKD. METHODS: A total of 11 clinically normal age-matched and 27 cats with naturally occurring CKD were included in this study. Circulating TGF-ß was quantified by immunoassays. Kaplan-Meier analysis was used to calculate the association between survival time and the concentration of circulating TGF-ß. A general linear model was used to compare the circulating TGF-ß between groups. Immunohistochemical analyses revealed TGF-ß expression in renal tissues from cats with CKD that died during the study (n = 7) and in available archived renal tissue specimens taken at necropsy from cats that had previous CKD with renal lesions (n = 10). Correlations of the TGF-ß expression and clinical parameters (n = 7) and histopathological changes (n = 17) were analysed using Spearman's rank correlation. RESULTS: The median survival time of cats with a lower concentration of circulating TGF-ß was shorter than that of cats with a higher concentration. The area under the curve of circulating TGF-ß for predicting CKD was 0.781, indicating good differentiation. The study indicated a significant difference in circulating TGF-ß concentrations between clinically normal cats and those with CKD and demonstrated that TGF-ß expression is correlated with tubular atrophy. CONCLUSIONS AND RELEVANCE: The study findings suggest that decreased serum TGF-ß and tubular atrophy with TGF-ß immunoreactivity may be significant in cats with CKD.

Antemortem cytologic diagnosis of pulmonary Langerhans cell histiocytosis in a cat.

Feline pulmonary Langerhans cell histiocytosis (FPLCH) is a rare histiocytic proliferative disease of middle-aged to older domestic cats. Langerhans cells in the terminal airways proliferate and infiltrate the interstitium and the airways to a lesser degree, widely effacing normal parenchyma. Historically, definitive diagnosis has required postmortem evaluation where pulmonary lesions have a classic gross and histologic morphology. Here, we present the first documented antemortem diagnosis of FPLCH using bronchoalveolar lavage (BAL) cytology and immunocytochemistry (ICC) in a 9-year-old British shorthair mix. The cat had a 3-month history of respiratory difficulty that was refractory to steroids and antimicrobials. Pulmonary radiographs had marked diffuse changes with a complex bronchointerstitial and micronodular pattern. BAL cytology revealed neutrophilic inflammation and markedly increased histiocytes with morphology distinct from typical pulmonary macrophages. ICC characterized histiocytes as CD1a+ /E-cadherin+ /CD11b- /PanCK- , consistent with a Langerhans cell phenotype. The cat was humanely euthanized due to poor prognosis and presented for necropsy. Gross, histopathologic, immunophenotypic, and ultrastructural findings confirmed a diagnosis of FPLCH. Proliferative cells were E-cadherin+ /Iba-1+ /CD18+ /CD1a+ /CD5+ /MHCII+ /CD204- /CD4- ; transmission electron microscopy identified the presence of Birbeck granules in the proliferating histiocytes, consistent with previous reports of FPLCH.

Retinoschisis: a retrospective study of an uncommon retinal change in cats and dogs.

Retinoschisis is a poorly documented form of retinal degeneration characterized by cyst-like splitting that occurs between the inner nuclear and outer plexiform layers. The pathogenesis of retinoschisis is incompletely understood, but congenital, acquired and secondary aetiologies (glaucoma, inflammation, neoplasia) are described in humans. This retrospective study investigated the prevalence and associated histological and clinical features of retinoschisis in cats and dogs submitted for biopsy over a 10-year period. Of 140 samples with documented 'retinal vacuolation', four out of 120 (3%) canine samples and one out of 20 (5%) feline samples had changes consistent with retinoschisis. In most cases (80%), there was concurrent retinal detachment. In cases with available histories, increased intraocular pressure, proptosis and retinal detachment were reported clinical findings. In cats and dogs, retinoschisis is a retinal change that is generally secondary to other ocular lesions.

Nephrology in Veterinary Medicine.

Veterinary nephrology is a specialized field of veterinary medicine providing a high level of care for animals with all types of kidney disease. Veterinarians complete extensive training to become board-certified in veterinary nephrology-urology. Companion animal nephrology is the most advanced field; however, all species are afflicted by a variety of renal disorders. Most naturally occurring animal kidney diseases have similar disorders found in people; where veterinary research is lacking, clinical management is often modified from standard of care in people. Veterinarians have become adept at scaling down procedures to safely perform them on dogs and cats weighing only a few kilograms. Advanced diagnostics (renal biopsy, cystoscopy, fluoroscopic studies, etc. ) and therapeutics (renal replacement therapy, interventional endourology, etc. ) are commonly performed within the practice of veterinary nephrology-urology. Collaboration between veterinary and human nephrologists may advance both disciplines and improve care for people and animals alike.

Immunohistochemical analysis of renal oxidative damage in senior and geriatric cats with chronic kidney disease.

Oxidative stress is a well-known cause of chronic kidney disease (CKD). In this study, renal oxidative damage in azotaemic and non-azotaemic aged cats with naturally occurring CKD was investigated using immunohistochemistry for 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 4-hydroxynonenal (4-HNE) as markers of oxidative tissue damage. Kidneys were obtained from aged (>10 years old) azotaemic (n = 13) and non-azotaemic (n = 7) cats. Immunoreactivity for 8-OHdG was found in the nuclei of glomeruli, proximal and distal tubules, loops of Henle and collecting ducts, whereas 4-HNE-positive signals were detected in the cytoplasm of distal nephrons in azotaemic and non-azotaemic cats. Quantitative analysis did not identify any significant differences between the azotaemic and non-azotaemic groups for any of the parameters examined. These results indicate that renal oxidative damage occurs in the kidneys of aged cats with CKD, regardless of whether they are azotaemic or non-azotaemic, emphasizing the importance of oxidative stress during early-stage CKD in senior and geriatric cats.

Eosinophilic cavitary effusions in cats: 48 cases (2010-2020).

BACKGROUND: Eosinophilic effusions are commonly defined as effusions with ≥10% eosinophils. Eosinophilic cavitary effusions are infrequently observed in cats, with few case reports comprising the majority of the recent literature. OBJECTIVE: The objective was to review disease associations of cats with eosinophilic cavitary effusions and to assess if a lower threshold of eosinophils (5%-9%) may warrant consideration of similar etiologies associated with effusions with ≥10% eosinophils. METHODS: Cytology reports were retrospectively reviewed for all feline cavitary effusions submitted for fluid analysis from 2010 to 2020 at a veterinary teaching hospital. Cases were included if the manual leukocyte differential included ≥5% eosinophils and separated into 5%-9% and ≥10% eosinophils groups. Patient records were reviewed for associated medical conditions. RESULTS: A total of 669 effusions were submitted from 579 cats; 50 effusions from 48 cats had a leukocyte differential with ≥5% eosinophils. The eosinophil proportion was ≥10% in 22 cats; the most common underlying cause was neoplasia (10/22, 45%), followed by inflammatory disease (4/22, 18%), cardiac disease (3/22, 14%), suspect neoplasia (3/22, 14%), and undetermined (2/22, 9%). The underlying causes for the 26 cats with 5%-9% eosinophils were similar; neoplasia (8/26, 31%), cardiac disease (6/26, 23%), inflammatory disease (4/26, 15%), suspect neoplasia (3/26, 12%), undetermined (3/26, 12%), and idiopathic chylothorax (2/26, 8%). Cats with eosinophil proportions ≥10% in the fluid exhibited peripheral eosinophilia more frequently (35%) compared to those with 5%-9% eosinophils (5%). CONCLUSIONS: Consistent with the current literature, neoplasia, particularly lymphoma, remains a primary consideration for cats with eosinophilic effusions. Previously unreported associated diseases included cardiovascular and inflammatory disorders. Our findings suggest an eosinophil differential of 5%-9% is seen with similar etiologies considered for classically defined eosinophilic effusions.

Hereditary myotonia in cats associated with a new homozygous missense variant p.Ala331Pro in the muscle chloride channel ClC-1.

Three-related cats were evaluated for a history of short-strided gait and temporary recumbency after startle. Neurological examination, electromyography (EMG), muscle biopsies, and a chloride voltage-gated channel 1 (CLCN1) molecular study were performed. Clinically, all 3 cats presented myotonia with warm-up phenomenon and myotonic discharges during EMG examination. Muscle biopsies showed normal muscle architecture and variation in the diameter of myofiber size with the presence of numerous hypertrophic fibers. The molecular study revealed a missense variant (c.991G>C, p.Ala331Pro) in exon 9 of the CLCN1 gene, responsible for the first chloride channel extracellular loop. This mutation was screened in 104 control phenotypically normal unrelated cats, and all were wildtype. The alanine at this position is conserved in ClC-1 (chloride channel protein 1) in different species, and 2 mutations at this amino acid position are associated with human myotonia. This is the third CLCN1 mutation described in the literature associated with hereditary myotonia in cats and the first in domestic animals located in an extracellular muscle ClC-1 loop.

Feasibility of feline coxofemoral arthroscopy using a supratrochanteric lateral portal: A cadaveric study.

OBJECTIVE: To evaluate the feasibility of feline diagnostic coxofemoral arthroscopy. STUDY DESIGN: Ex vivo feline cadaveric descriptive study. ANIMALS: Seven feline cadavers (14 hips). METHODS: Gross dissection of two feline hips was performed to evaluate anatomic landmarks, guide arthroscopic portal development, and determine optimal limb positioning. A 1.9 mm, 0° arthroscope, inserted through a supratrochanteric lateral portal, was used to assess intraarticular structures in 12 feline cadaver hips. Arthroscopy was followed by gross dissection of periarticular soft tissues. Relative portal locations and damage to periarticular structures were recorded. Hips were disarticulated, and an India ink assay was performed to assess whether there was iatrogenic cartilage injury (ICI). RESULTS: Scope insertion was achieved in all hips. Articular cartilage of the femoral head and acetabulum, round ligament, joint capsule, transverse acetabular ligament, and dorsal acetabular rim were identified arthroscopically in all hips. Probe insertion and intra-articular structure palpation was achieved in all hips. Scope and instrument portals resulted in minimal periarticular muscle trauma. No sciatic nerve damage was detected. Minor partial thickness ICI was observed in all hips at the site of scope insertion. Focal full thickness ICI was noted in one hip. CONCLUSION: Arthroscopy of the feline coxofemoral joint allowed visual and probe evaluation of intra-articular structures without evidence of major periarticular neurovascular trauma. Iatrogenic cartilage injury occurred in all hips but severity of lesions was considered mild. CLINICAL SIGNIFICANCE: Coxofemoral arthroscopy is feasible in cats and can be utilized as a diagnostic tool for minimally invasive joint evaluation.