Retrospective study and outcome of 307 cats with feline infectious peritonitis treated with legally sourced veterinary compounded preparations of remdesivir and GS-441524 (2020-2022).

OBJECTIVES: Feline infectious peritonitis (FIP) is a serious disease that arises due to feline coronavirus infection. The nucleoside analogues remdesivir and GS-441524 can be effective in its treatment, but most studies have used unregulated products of unknown composition. The aim of the present study was to describe the treatment of FIP using legally sourced veterinary-prescribed regulated veterinary compounded products containing known amounts of remdesivir (injectable) or GS-441524 (oral tablets). METHODS: Cats were recruited via email advice services, product sales contacts and study publicity. Cats were excluded if they were deemed unlikely to have FIP, were not treated exclusively with the veterinary compounded products, or if there was a lack of cat and/or treatment (including response) data. Extensive cat and treatment data were collected. RESULTS: Among the 307 cats recruited, the predominant type of FIP was most commonly abdominal effusive (49.5%) and then neurological (14.3%). Three treatment protocols were used; remdesivir alone (33.9%), remdesivir followed by GS-441524 (55.7%) and GS-441524 alone (10.4%). The median (range) initial treatment period duration and longest follow-up time point after starting treatment were 84 (1-330) days and 248 (1-814) days, respectively. The most common side effect was injection pain (in 47.8% of those given subcutaneous remdesivir). Of the 307 cats, 33 (10.8%) relapsed, 15 (45.5%) during and 18 (54.5%) after the initial treatment period. At the longest follow-up time point after completion of the initial treatment period, 84.4% of cats were alive. The cats achieving a complete response within 30 days of starting treatment were significantly more likely to be alive at the end of the initial treatment period than those cats that did not. CONCLUSIONS AND RELEVANCE: Legally sourced remdesivir and GS-441524 products, either alone or used sequentially, were very effective in the treatment of FIP in this group of cats. Variable protocols precluded statistical comparison of treatment regimens.

Bacteriuria in Cystocentesis Samples from Cats in the United Kingdom: Prevalence, Bacterial Isolates, and Antimicrobial Susceptibilities.

Bacterial urinary tract infections (UTIs) have historically been reported to be uncommon in cats; however, recent studies showed a higher prevalence. Bacterial UTIs are one of the most common reasons for the use of antimicrobial drugs in veterinary medicine. Our aim was to investigate the prevalence of positive cultures in urine samples submitted to a UK laboratory for testing, as well as prevalence of bacterial species and their antimicrobial susceptibility to commonly used antibiotics. This was a retrospective analysis of positive cultures from feline urine samples collected by cystocentesis submitted over 14 months (January 2018-February 2019). A total of 2712 samples were reviewed, of which 425 documented a positive culture (15.7%) with a total of 444 bacterial isolates. E. coli (43.7%), other Enterobacterales (26.4%), Enterococcus species (14.9%) and Staphylococcus species (9.2%) were the most commonly isolated bacteria. E. coli most commonly showed resistance to cephalexin (20.7%) and amoxicillin (16.7%). Resistance was most commonly seen against amoxicillin (64.1%) and cephalexin (52.2%) in Enterobacterales. Enterococcus species most commonly showed resistance to trimethoprim/sulfamethoxazole (94.3%). Staphylococcus species most commonly showed resistance to amoxicillin (20%). This study showed significant resistance of bacteria found in feline urine samples in the UK to frequently used antibiotics.

Gallbladder adenoma in a domestic shorthair cat.

A 13-year-old neutered female domestic shorthair rescue cat presented asymptomatically with raised hepatic enzymes following a routine pre-anaesthetic blood test. Cholangitis was suspected, and supportive treatment with 2 weeks of amoxicillin-clavulanic acid and 4 weeks of ursodeoxycholic acid and S-adenosylmethionine was trialled, with no improvement in biochemistry parameters. Clinicopathological investigations also revealed a markedly raised total bilirubin and abnormal bile acid stimulation test. Abdominal ultrasonography revealed pathological changes in the gallbladder, hepatomegaly with increased echogenicity and markedly thickened common bile duct walls. An exploratory laparotomy was performed revealing a grossly abnormal gallbladder with a small rupture at the dorsal fundus, which was managed via cholecystectomy. Pancreatic and hepatic biopsies were collected concurrently. Histopathology from the submitted samples revealed a gallbladder adenoma, chronic neutrophilic cholangitis and nodular hyperplasia of the pancreas. Culture of the gallbladder bile was negative but may be attributable to the initial treatment with antibiosis. At the time of writing, 5 months postoperatively, the cat had recovered well and remained asymptomatic and clinically healthy, but hepatic enzymes and bilirubin were only mildly reduced from the preoperative levels, despite the cat remaining clinically normal. RELEVANCE AND NOVEL INFORMATION: To our knowledge, this is the first case of a gallbladder adenoma confirmed histopathologically in a feline patient. Our findings suggest that although gallbladder neoplasia is rare in cats, this benign tumour should be considered a differential diagnosis.

A case of an intramural, cavitated feline gastrointestinal eosinophilic sclerosing fibroplasia of the cranial abdomen in a domestic longhair cat.

CASE SUMMARY: A 5-year-old neutered male domestic longhair cat was presented for the investigation of a cranial abdominal mass following a 1-month history of inappetence and lethargy. Abdominal ultrasound revealed a large cavitated mass confluent with the mesenteric aspect of the descending duodenum. At surgery, the mass was found to involve the pylorus, proximal duodenum and pancreas, and was non-resectable. Histopathological examination of surgical biopsies revealed a non-neoplastic process involving eosinophils and fibroplasia. RELEVANCE AND NOVEL INFORMATION: This case report describes an uncommon feline gastrointestinal pathology with an unusual appearance that may provide an additional differential diagnosis other than neoplasia or abdominal abscess when confronted with a cavitated abdominal mass in cats.

Intranasal proliferative fibro-osseous dysplasia in a domestic longhair cat.

CASE SUMMARY: A 13-year-old female domestic longhair cat was presented for further investigation of chronic sneezing combined with a right-sided nasal discharge. A CT scan of the head revealed a locally invasive, aggressive right nasal mass radiographically consistent with a malignant neoplastic process. Histopathology on rhinoscopically guided biopsies revealed an unusual pathology consistent with fibro-osseous hyperplasia/dysplasia. Surgical treatment via a ventral rhinotomy and curettage was performed, and the diagnosis confirmed by repeat histopathology. The cat's clinical signs significantly improved postoperatively. RELEVANCE AND NOVEL INFORMATION: This case report describes an unusual feline nasal pathology. To our knowledge, there are no previous reports of a non-neoplastic, non-inflammatory expansile feline nasal tumour. Also described are the CT and histological appearance of the mass, and the difficulties encountered obtaining the definitive diagnosis. Information regarding the prognosis following surgical removal of proliferative fibro-osseous lesions in cats is poor, especially from the nasal cavity where clean margins may well be impossible to obtain. In this case, surgical resection improved clinical signs and the cat remains well at 15 months post-procedure.

ISFM Consensus Guidelines on the Diagnosis and Management of Hypertension in Cats.

Practical relevance: Feline hypertension is a common disease in older cats that is frequently diagnosed in association with other diseases such as chronic kidney disease and hyperthyroidism (so-called secondary hypertension), although some cases of apparent primary hypertension are also reported. The clinical consequences of hypertension can be severe, related to 'target organ damage' (eye, heart and vasculature, brain and kidneys), and early diagnosis followed by appropriate therapeutic management should help reduce the morbidity associated with this condition. Clinical challenges: Despite being a common disease, routine blood pressure (BP) monitoring is generally performed infrequently, probably leading to underdiagnosis of feline hypertension in clinical practice. There is a need to: (i) ensure BP is measured as accurately as possible with a reproducible technique; (ii) identify and monitor patients at risk of developing hypertension; (iii) establish appropriate criteria for therapeutic intervention; and (iv) establish appropriate therapeutic targets. Based on current data, amlodipine besylate is the treatment of choice to manage feline hypertension and is effective in the majority of cats, but the dose needed to successfully manage hypertension varies between individuals. Some cats require long-term adjuvant therapy and, occasionally, additional therapy is necessary for emergency management of hypertensive crises. Evidence base: These Guidelines from the International Society of Feline Medicine (ISFM) are based on a comprehensive review of the currently available literature, and are aimed at providing practical recommendations to address the challenges of feline hypertension for veterinarians. There are many areas where more data is required which, in the future, will serve to confirm or modify some of the recommendations in these Guidelines.

Feline mediastinal lymphoma: a retrospective study of signalment, retroviral status, response to chemotherapy and prognostic indicators.

Historically, feline mediastinal lymphoma has been associated with young age, positive feline leukaemia virus (FeLV) status, Siamese breed and short survival times. Recent studies following widespread FeLV vaccination in the UK are lacking. The aim of this retrospective multi-institutional study was to re-evaluate the signalment, retroviral status, response to chemotherapy, survival and prognostic indicators in feline mediastinal lymphoma cases in the post-vaccination era. Records of cats with clinical signs associated with a mediastinal mass and cytologically/histologically confirmed lymphoma were reviewed from five UK referral centres (1998-2010). Treatment response, survival and prognostic indicators were assessed in treated cats with follow-up data. Fifty-five cases were reviewed. The median age was 3 years (range, 0.5-12 years); 12 cats (21.8%) were Siamese; and the male to female ratio was 3.2:1.0. Five cats were FeLV-positive and two were feline immunodeficiency-positive. Chemotherapy response and survival was evaluated in 38 cats. Overall response was 94.7%; complete (CR) and partial response (PR) rates did not differ significantly between protocols: COP (cyclophosphamide, vincristine, prednisone) (n = 26, CR 61.5%, PR 34.0%); Madison-Wisconsin (MW) (n = 12, CR 66.7%, PR 25.0%). Overall median survival was 373 days (range, 20-2015 days) (COP 484 days [range, 20-980 days]; MW 211 days [range, 24-2015 days] [P = 0.892]). Cats achieving CR survived longer (980 days vs 42 days for PR; P = 0.032). Age, breed, sex, location (mediastinal vs mediastinal plus other sites), retroviral status and glucocorticoid pretreatment did not affect response or survival. Feline mediastinal lymphoma cases frequently responded to chemotherapy with durable survival times, particularly in cats achieving CR. The prevalence of FeLV-antigenaemic cats was low; males and young Siamese cats appeared to be over-represented.

Serum thymidine kinase activity in clinically healthy and diseased cats: a potential biomarker for lymphoma.

The thymidine kinases are enzymes that convert deoxythymidine to deoxythymidine monophosphate and have a function in DNA synthesis. Rapidly proliferating cells will have higher levels of thymidine kinase. Serum thymidine kinase activity (sTK) is a useful tumour marker in humans and dogs, with utility as a prognostic indicator in lymphoma. In the current study serum samples were collected from 49 clinically healthy cats, 33 with lymphoma, 55 with inflammatory disease and 34 with non-haematopoietic neoplasia (NHPN). sTK was measured using a radioenzyme assay and a reference interval (1.96 × SD) was established from the clinically healthy cats (<5.5 U/l). Mean sTK activity for healthy cats was 2.2 U/l (range 0.8-8.4, ± SD 1.7). Mean sTK activity for cats with lymphoma was 17.5 U/l (range 1.0-100.0 SD ± 27.4). Mean sTK activity for cats with NHPN was 4.2 U/l (range 1.0-45.0, SD ± 8.6). Mean sTK activity for the inflammatory group was 3.4 U/l (range 1.0-19.6, SD 3.9). Cats with lymphoma had significantly higher sTK activity than healthy cats or cats with inflammatory disease (P <0.0001) and cats with NHPN (P <0.0002). sTK activity is a potentially useful biomarker for feline lymphoma and further study is required to assess its utility as a prognostic indicator.

Serum protein electrophoresis in 155 cats.

All serum protein electrophoresis (SPE) results obtained between 2002 and 2009 from clinical cases presented to the University of Bristol Feline Centre were examined retrospectively. One hundred and fifty-five results met the inclusion criteria. Signalment and final diagnoses were obtained from the case records. Clinical cases were classified as having normal or abnormal SPE results by comparison to reference intervals for SPE created using 77 clinically normal cats. Abnormal results were then further divided according to the specific SPE abnormality. Cases were also categorised, according to the final diagnosis, using the DAMNITV classification system. Of the 155 cases, 136 (87.7%) had abnormal SPE results, most commonly due to a polyclonal increase in gamma globulins. A monoclonal gammopathy occurred in four cats; one with feline infectious peritonitis (FIP), one with lymphoma and two cases of splenic plasmacytoma (one suspected, one confirmed). The most common DAMNITV classification associated with SPE abnormalities was infectious/inflammatory disease (80/136; 58.8%), including 39 cats diagnosed with FIP.

Laryngeal disease in cats: a retrospective study of 35 cases.

The aim of this retrospective study was to review the medical records of cats referred to the University of Bristol for investigation of laryngeal disease (n=35). Cases were categorised into one of four groups: cats with laryngeal paralysis (LP, n=14), laryngeal neoplasia (n=10), laryngeal inflammation (n=6), or miscellaneous laryngeal diseases (n=5). Laryngoscopy and echolaryngography were useful diagnostic techniques but histology was required for diagnosis of diseases other than LP. Two cats with lymphoma received chemotherapy achieving survival times of 60 and 1440 days. Four cats with LP were treated surgically, with a median survival time of 300 days (range 10-360 days) and six were treated conservatively with a median survival time of 780 days (range 300-2520 days). Three cats with inflammatory disease were treated medically and one by excision of the lesion. Two cats achieved survival times of 120 and 2800 days. Cats with LP, laryngeal lymphoma or laryngitis had excellent long-term survival following appropriate treatment.