Feline chronic progressive polyarthritis

Twenty cats with a chronic progressive polyarthritis were studied. The disorder occurred exclusively in male cats, and all but six of the cats were between 1.5 and 5.0 years of age. There were two forms of the disease as determined by radiographic changes: joint instability and deformity, and clinical course. The most prevalent form of the disease was characterized by osteopenia and periosteal new bone formation surrounding affected joints. Marginal periarticular erosions and collapse of the joint spaces with fibrous ankylosis occurred with time, but joint instability and deformities were not seen. The second form of the disease was characterized by severe subchondral marginal erosions, joint instability, and deformities. The periosteal proliferative form resembled Reiter's arthritis of man, and the deforming type resembled human rheumatoid arthritis. The disease began as tenosynovitis and synovitis, with subsequent changes in the articular cartilage and periosteal bone. Histopathologic changes in these cats were similar to those occurring in both chronic Reiter's and rheumatoid arthritis of man. Chronic progressive polyarthritis of cats was not caused by identifiable bacteria or mycoplasma, but was etiologically linked to feline leukemia virus (FeLV) and feline syncytia-forming virus (FeSFV) infections. The FeSFV was isolated from the blood or was detected by a serologic test in all of the cats with the disease, whereas FeLV was isolated or identified by immunofluorescence technique in 60% of the cats. The arthritis could not be reproduced by inoculation of cell-free cynovial tissue from diseased cats or with tissue culture fluid containing FeSFV and FeLV isolates. It was postulated that arthritis was an uncommon manifestation of FeSFV infection that occurred in predisposed male cats. Feline leukemia virus may not have been directly involved in the disease, but may have acted in some way to potentiate the pathogenic effects of FeSFV.     

Feline osteoarthritis: a prospective study of 28 cases

OBJECTIVES: To identify a cohort of cats with clinical osteoarthritis and to report on the clinical signs, the frequency of joints affected and the possible aetiopathogenesis within this population. METHODS: Inclusion criteria for this prospective study were presence of historical evidence and/or clinical signs of osteoarthritis, together with radiographic evidence of osteoarthritis. Patients showed clinical improvement within four weeks of analgesic administration and were free from other disease processes, which might explain the clinical signs and/or their response to analgesia. RESULTS: Twenty-eight cases were included in the cohort. The elbow (45 per cent) and the hip (38 per cent) were the most frequently affected joints. Seventy-one per cent of cases had primary/idiopathic aetiology. Alterations in both the ability to jump (71 per cent) and the height (67 per cent) of jump (lifestyle changes) were the most frequent signs of disease. Sixty-one per cent of owners felt that their pet had made a marked improvement following administration of an analgesic/anti-inflammatory drug. There were statistically significant improvements in the ability to jump (P < 0.001), the height of jump (P < 0.001), lameness (P = 0.03), stiff gait (P = 0.04) and the activity level (P = 0.02) when compared with the start and the end of the study period. CLINICAL SIGNIFICANCE: Osteoarthritis is a clinical problem in cats, but overt lameness is not the most common clinical feature.     

Feline plasma cell pododermatitis: a study of 8 cases

Eight cases of feline plasma cell pododermatitis, collected over a 3-year period, were studied using histological (haematoxylin and eosin), histochemical (methyl green-pyronin) and immunohistochemical (antibody against lambda light chains of immunoglobulins) techniques. No sex, breed or age predisposition, or paw predilection was observed. The disease began as a swelling of the footpads, followed by ulceration. Histologically, lesions were characterized by the presence of a large number of plasma cells in a predominantly perivascular pattern. Binucleated plasma cells and mitotic figures were observed. Clinical follow-up for over 1 year revealed total remission of the lesions both after glucocorticoid therapy in four cases, and total surgical excision in two animals. Follow-up studies were not possible in one case.     

Feline urate urolithiasis: a retrospective study of 159 cases

The objective of the study was to characterize the signalment, clinicopathologic data, and diagnostic imaging of cats with urate urolithiasis, as well as the salts of uric acid present in the uroliths. A retrospective analysis of feline urate uroliths submitted to the GV Ling Urinary Stone Analysis Laboratory between 2000 and 2008 was included. From these data, records were assimilated from referring veterinarians (143); furthermore, all recorded cases from within the William R Pritchard Veterinary Medical Teaching Hospital (16) were included. Median values for the complete blood count and chemistry panels available were within the reference intervals, when provided, with only a few outliers present. Of all cases evaluated, seven had a portosystemic shunt (PSS). Cats with urate uroliths and a PSS were younger than cats without a PSS (2 years vs 7 years). The pathogenesis of urate uroliths in cats is poorly understood. Most cats were not completely evaluated for a PSS, however, clinicopathologic parameters indicating hepatic dysfunction were seldom noted; more sensitive diagnostics such as serum bile acids were rarely performed to confirm or negate the presence of a shunt. Studies are warranted to evaluate pathogenesis of urate uroliths to tailor proper management and breeding strategies.     

Feline exocrine pancreatic carcinoma: a retrospective study of 34 cases

Thirty‐four cases were reviewed in this retrospective study for information on clinical presentation, prognostic indicators, survival time and response to various therapies. The most common presenting clinical signs were weight loss, decreased appetite, vomiting, palpable abdominal mass and diarrhoea. Metastatic disease was confirmed in 11 cats. The overall median survival was 97 days. The median survival times for patients who received chemotherapy or had their masses surgically removed was 165 days. Those patients who had an abdominal effusion present at the time of diagnosis survived a median of 30 days. Cats that received non‐steroidal anti‐inflammatory drug therapy had a median survival of 26 days. This study confirms that exocrine pancreatic carcinoma in cats is an aggressive tumour with a high metastatic rate and poor prognosis, although three patients survived over 1 year. Fifteen percent of the patients were diabetic, which raises the question as to what the link between diabetes and pancreatic cancer in people and cats may be.     

Feline pyothorax: a retrospective study of 27 cases in Australia

Pyothorax was diagnosed in 27 cats between 1983 and 2002. In 21 (78%) of the cases, pleural fluid culture and/or cytology was consistent with a mixed anaerobic bacterial infection of oropharyngeal origin. In six cases (22%), infection was caused by unusual pathogens or pathogens of non-oropharyngeal origin, including a Mycoplasma species, Cryptococcus gattii, Escherichia coli, Salmonella typhimurium and Staphylococcus aureus. The overall mortality rate was 22%. Treatment was successful in 18 of 19 cases (95%) where closed thoracostomy tubes were inserted. One case resolved only after thoracotomy. Actinomyces species were isolated in three cases and in contrast to dogs where thoracotomy is recommended, they were resolved with tube thoracostomy. Mechanical complications occurred in 58% of the cats with indwelling chest tubes. Probable mechanisms of pleural space infection were identified in 18 cats (67%) including haematogenous infection (n=1), direct inoculation of bacteria into the pleural space (n=1), intrathoracic oesophageal rupture (n=1) and parapneumonic extension of infection (n=15; 56%). Of the latter, perioperative aspiration was suspected in two cats, parasitic migration in two and antecedent upper respiratory tract infection was implicated in seven. Parapneumonic spread of infection after colonisation and invasion of lung tissue by oropharyngeal flora appears to be the most frequent cause of feline anaerobic polymicrobial pyothorax and contests the widespread belief that direct inoculation of pleural cavity by bite wounds is more common.     

FC-23 Feline plasma cell pododermatitis: a retrospective study of 26 cases

The objective of this open pilot study was to evaluate the efficacy of topical tacrolimus ointment for treatment of plantar fistulae in German shepherd dogs. Seven dogs (four males, three females) were included. All subjects had a 6-month to 2-year history of plantar fistulae involving the plantar aspect of two to four metatarsi/metacarpi. No other skin lesions were present and the dogs appeared otherwise healthy. Before treatment with tacrolimus, all dogs received antibiotics for 4–8 weeks. Hair was clipped to visualise the lesions. The presence of erythematous papules, oedema and fistulae was recorded for each foot. All dogs served as their own controls. Dogs with four legs involved had one front and one hind leg treated. Dogs with two to three feet affected had only one foot treated. Tacrolimus 0.1% ointment (Protopic^®) was applied twice daily onto the site of lesions. Partial improvement of treated lesions was seen in all cases within 3 weeks. After 6 weeks, treated lesions were in complete remission in four dogs, while the other three subjects had palpable but invisible lesions. Signs had not improved on the untreated legs. Follow-up varied between 4 months and 2 years. Lesion remission persisted in six dogs with the intermittent application of tacrolimus. Adverse effects of treatment were not seen. In conclusion, the application of topical tacrolimus seems to provide a safe and effective treatment option for plantar fistulae in German shepherd dogs.
Funding: Self-funded.     

Feline dysautonomia in the Midwestern United States: a retrospective study of nine cases

Dysautonomia of domestic animals is pathologically characterized by chromatolytic degeneration of the neurons in the autonomic nervous ganglia that results in clinical signs related to dysfunction or failure of the sympathetic and parasympathetic nervous systems. The exact cause is unknown. It has a poor prognosis among all species reported and no definitive treatment is available currently. To date, most reported feline cases have occurred in the United Kingdom and Scandinavia. The cases reported here highlight the clinical signs, physical examination findings, and results of autonomic nervous system function testing in nine cats with dysautonomia in the US. Feline dysautonomia is uncommon in the US, but may have a regional prevalence, as is seen in dogs with most cases reported in Missouri and Kansas.     

Feline histoplasmosis: a retrospective study of 22 cases (1986-2009)

Twenty-two cases of feline histoplasmosis seen at the Virginia-Maryland Regional College of Veterinary Medicine Teaching Hospital between 1986 and 2009 were reviewed. The median age of affected cats was 9 yr (mean, 8.8 yr). Female domestic shorthairs were more commonly affected. The clinical presentation of most cases was nonspecific. The most common presenting complaints included weakness, lymphadenopathy, weight loss, and anorexia. Less frequent clinical signs included vomiting, diarrhea, blindness, and lameness. Less than half of the cats had clinical evidence of pulmonary disease on admission. Anemia and hypoalbuminemia were common laboratory abnormalities. An interstitial pattern was the most common radiographic pattern observed with pulmonary disease. Diagnosis was based on identification of the organism on cytology or histopathology. Fifteen of the 22 cats were treated, and itraconazole was the most common antifungal agent prescribed. Median duration of the antifungal treatment was 5 mo for cats that survived to discharge. Overall survival at time of discharge for cats in this study was 55%.     

Feline necrotising sialometaplasia: a report of two cases

Unilateral swelling of submandibular salivary gland in two cats was diagnosed as necrotising sialometaplasia. Histological features that differentiate the disease from other salivary gland lesions, particularly neoplasia are: lobular necrosis of salivary tissue; squamous metaplasia conforming to duct and/or acinar outlines; preservation of salivary lobular morphology; and variable inflammation and granulation tissue.     

Feline cutaneous hemangiosarcoma: a retrospective study of 18 cases (1998-2003)

Cutaneous hemangiosarcoma (HSA) has been infrequently reported in dogs and cats. Medical records of 18 cats diagnosed with cutaneous HSA were reviewed. Age at the time of diagnosis, breed, sex, tumor location, tumor size, treatment type, survival time, disease-free interval, and cause of death were evaluated. Aggressive surgical excision of the tumor was attempted in 10 cats. A complete surgical excision was achieved in five of the 10 cats. Median survival times were statistically longer in cats that underwent surgery versus cats that did not. Cats with cutaneous HSA treated with aggressive surgical excision of their tumors may have a good long-term prognosis.     

Feline non-ocular melanoma: a retrospective study of 23 cases (1991-1999).

Non-ocular melanoma is considered to be a rare neoplasm in cats; however, more than 150 cases have been reported in the literature since 1961. The objective of this study was to characterise this tumour better by evaluating case outcome and survival data for cats with melanoma and to compare clinical and histopathological findings with those of previous reports. Twenty-three feline non-ocular melanomas were identified, the most common locations being the nose, digit and pinna. Cats with digital melanomas had survival rates similar to their canine counterparts. Histological assignation of benignity, malignancy or junctional activity was not found to be an accurate predictor of clinical behaviour. Melanoma should be considered as a differential diagnosis for cats presenting with pigmented or non-pigmented masses and histopathology is essential for definitive diagnosis, as other tumours may clinically appear quite similar. Regular follow-up examinations are recommended indefinitely for benign or malignant feline melanomas.     

Feline superficial pyoderma: a retrospective study of 52 cases (2001-2011)

Background – Superficial pyoderma is traditionally considered rare in cats but may be more prevalent than previously reported. Objectives – To better characterize superficial pyoderma in cats. Animals – Fifty‐two cats from a dermatology referral population over a 10 year period. Methods – This study was retrospective. Cases were included if neutrophils and intracellular bacteria were reported from surface cytology of skin lesions. Medical records were reviewed for signalment, historical and clinical data, cytology results, primary skin diagnoses and treatment details. Results – Disease prevalence was 20%, with no breed or sex predispositions. The estimated median age of onset was 2 years, affecting 54% of cats by 3 years and 23% after 9 years. Fewer cases presented during winter (15%) compared with other seasons. Skin lesions were typically multifocal, affecting the face (62%), neck (37%), limbs (33%) and ventral abdomen (29%) most commonly. Crusting (83%), alopecia (67%), ulceration/erosion (54%) and erythema (46%) were common lesion types. Pruritus was reported in 92% of cats. Underlying hypersensitivities (confirmed in 60%; suspected in 19%), and atopic dermatitis specifically (confirmed in 48%), were the most frequent primary dermatoses. Cats were treated with a variety of systemic and/or topical antimicrobials. The overall apparent response was considered good in 61% and poor in 27% of cats. Recurrence was confirmed or suspected in 42% of cats. Conclusions and clinical importance – Feline superficial pyoderma was more prevalent in this study population than previously reported. Young cats with hypersensitivities and older cats were more commonly affected, and a variety of lesion types and distributions occurred.     

Feline lower airway disease: a retrospective study of 22 naturally occurring cases from Greece

In this retrospective study of 22 cats with lower airway disease of either intermittent (23%) or persistent nature (77%), the Siamese breed (55%) was significantly over-represented. Females (68%) were slightly but not significantly over-represented. No significant association was found between the clinical stage of disease and the physical findings, thoracic radiographic changes or the response to treatment. Cough, the most common presenting complaint, was the only symptom detected in the cats with intermittent disease, yet the two most severely affected animals did not show it. Thoracic auscultation did not reveal any abnormality in 41% of the cats. Haematology revealed eosinophilia in 46% of the cats. A bronchial pattern was the most common radiographic abnormality (73%), followed by alveolar (32%) and interstitial patterns (23%). Interestingly, thoracic radiographs were normal in 23% of the cats. The combination of short-term corticosteroids and bronchodilators resulted in complete and long-term remission of symptoms in nine cats, while the other 11 required ongoing medication because of relatively frequent relapses. One of the remaining two cats died during an asthmatic crisis, while the other was lost to follow up.     

Feline mammary carcinoma: a retrospective evaluation of 17 cases

Seventeen biopsies of feline mammary carcinoma submitted to the Veterinary Pathology Laboratory, Nova Scotia Department of Agriculture and Marketing were reviewed. All 17 cases were female cats. Data on age, reproductive status (sexually intact vs. neutered), therapy, outcome of the cases and histological features were consistent with data on feline mammary carcinoma previously reported. Four of these 17 cats had a history of receiving exogenous progestin prior to tumor development. The possible role of progestins as initiators or promoters of feline mammary carcinoma was discussed. The use of feline mammary carcinoma as a model for carcinoma of the breast in women was reviewed.     

Feline pemphigus foliaceus: a retrospective analysis of 57 cases

Fifty-seven cases of feline pemphigus foliaceus were identified from biopsy specimens submitted to University of Pennsylvania School of Veterinary Medicine's Laboratory of Pathology and Toxicology by veterinary dermatologists from 1991 to 2002. Age at onset ranged from less than 1 year to 17 years; median 5 years. Eighty per cent of cats were reported to have been pruritic. At the time of biopsy, the distribution of lesions varied, but included some combination of face/head, paws, dorsum or ventrum and consisted of crusts, erosions, scale and alopecia. The histological features of 208 biopsy specimens were reviewed and included the following. Acantholytic cells were found in large numbers in both intact and degenerating pustules in most cases. Mast cells were found in the dermal infiltrate more often than reported previously. Seventeen cases were receiving corticosteroids at the time of biopsy; reducing the percentage of diagnostic biopsies per case. Forty-four cases were followed for 1-54 months (median 9 months). Triamcinolone was more successful at inducing remission without significant adverse effects than prednisone or prednisone in combination with chlorambucil. Only 4/44 cats died from their disease or therapy during the study period.     

Feline cystic thymoma: a clinicopathologic,immunohistologic, and electron microscopic study of 14 cases

Cystic thymoma was diagnosed in 14 cats in a period of 6 years. The most common clinical sign was laboured breathing. The tumours were characterized by various-sized cystic spaces with central vessels. The epithelial cells varied from oval to spindle to polygonal cells enclosing cystic spaces or in pure epithelial cell components. The nuclei of the neoplastic cells had scattered chromatin and small nucleoli. The cytoplasm was pale eosinophilic. The concentration of mature lymphocytes varied from area to area with rare germinal centres. Immunohistochemically, the epithelial cells stained only with AE(1)/AE(3). The central vessels were positive for vimentin, smooth muscle actin, and factor VIII antigen. Electron microscopy revealed that the cyst walls were lined by epithelial cells that were joined by desmosomes, and the walls were well separated from the cystic spaces by a well-defined basement membrane. The neoplastic epithelial cells contained scattered tonofilaments. Three of the cats had metastasis to the lymph nodes and lungs. Two novel cases of ectopic cystic thymoma have also been described. Results of this study reveal that cystic thymoma is uncommon in cats, and that the histomorphologic, immunohistochemical, and electron microscopic features are similar to those of cystic thymoma in humans.