Sophie Broughton

Background: Subcutaneous ureteral bypass (SUB) can be an effective treatment for ureteral obstruction in cats, but SUB explantation is little documented. Hypothesis/Objectives: Describe reasons for SUB explantation, outcomes, and owner experiences. We hypothesized that explantation would be effective in managing common SUB-related complications. Animals: Twenty-one cats (31 SUBs) that underwent 29 explantations. Methods: Retrospective case-series of cats undergoing explantation between 2015 and 2023 with medical record review and 20 owners emailed for follow-up. Results are median (range). Results: Explantation was performed 1.8 years (0.2-4.1 years) after placement because of positive urine culture (PUC; 15/21), SUB obstruction (8/21), sterile cystitis (4/21), and suspected SUB failure (2/21). Twenty-six out of 31 ureters had documented patency. Seventeen cats had all implants removed (9 unilateral, 8 bilateral). Two underwent unilateral explantation and ipsilateral ureteronephrectomy. Two with bilateral SUBs underwent unilateral explantation. Follow-up after explantation was 596 days (3-2310 days). Four cats had ureteral re-obstruction (1 after partial obstruction at explantation), 10 did not re-obstruct and the remainder were undetermined. Seven cats died at 614 days (405-2200 days), 11 were lost to follow-up at 135 days (19-1774 days) after explantation, and 3 remained alive. Four deaths were renal related (2/4 re-obstructions). Nine of 15 cats explanted due to PUC had a negative postoperative urine culture. Three of 15 cats had clinical signs related to PUC postoperatively. Questionnaire response was 9 of 20, and 8 of 9 owners would consider explantation if in the same situation again. Conclusions and clinical importance: For SUB cats with complications, explantation is a viable option. A small proportion of cats had clinical signs of PUC, or ureteral re-obstruction postoperatively.

Case summary: This report describes a 14-year 9-month-old male neutered cat with a primary adrenal tumour secreting aldosterone with pulmonary metastases, alongside concurrent hyperthyroidism and congestive heart failure. The cat presented with hyporexia and muscular weakness including marked cervical ventroflexion. Hypokalaemia, hypertension, marked hyperaldosteronaemia and presence of a left-sided adrenal mass were consistent with primary hyperaldosteronism and pulmonary nodules were detectable radiographically. Congestive heart failure and poor quality of life resulted in euthanasia. Microscopic examination identified an adrenocortical carcinoma and the histologic morphology and immunohistochemical labelling was similar between the primary tumour and pulmonary nodules. Relevance and novel information: Primary hyperaldosteronism is an underdiagnosed condition of cats, causing hypertension and hypokalaemia. Excessive aldosterone is secreted by the adrenal glands and may be caused by tumours. Around half of aldosterone secreting tumours in cats are malignant, although distant metastases have only been reported once previously. This is the first report of radiographically evident pulmonary metastases from an aldosterone secreting adrenal tumour confirmed by immunohistochemical labelling.

Background: Vaccination is implicated in development of human immune-mediated diseases, but studies in dogs yielded conflicting results for immune-mediated hemolytic anemia (IMHA) and thrombocytopenia (ITP). Hypothesis/Objectives: To investigate temporal relationships between onset of IMHA or ITP and vaccination in dogs. Animals: Client-owned dogs with nonassociative IMHA (n = 295) and ITP (n = 163) at 4 referral hospitals, alongside control dogs (n = 1180 for IMHA, 652 for ITP) presented contemporaneously. Methods: Multicenter retrospective case–control study, with meta-analysis of published studies. Proportions vaccinated ≤ 30 days before disease onset were compared to controls, along with times since last vaccine. Results: Proportion of dogs vaccinated ≤ 30 days of disease onset was significantly higher in the IMHA group (35/295, 11.9%) compared with controls (72/1180, 6.1%; P = .0015). Dogs with IMHA vaccinated ≤ 30 days of disease onset were more likely to have received a L2 vaccine (Leptospira serovars Canicola and Icterohemorrhagiae) in their last dose than those vaccinated > 30 days before onset (P = .04). Meta-analysis indicated dogs with IMHA were 2.48 times (95% CI, 1.69-3.63) more likely to have been vaccinated in the past month than controls, but with high heterogeneity across this and 2 other studies. There was no difference in proportion of ITP dogs and controls vaccinated ≤ 30 days of disease onset, and meta-analysis with 1 other study showed no temporal association, though both analyses were likely underpowered. Conclusions and clinical importance: These results support a possible temporal association between vaccination and onset of IMHA in dogs. Our results do not establish a causal relationship between vaccination and IMHA.

Background: Obesity is associated with insulin resistance and affects glycemic control in diabetic patients. Hypothesis/Objectives: Assess the impact of 12-week caloric restriction on remission and glycemic control in overweight diabetic cats using a prospective, randomized controlled trial. Animals: Seventy-two overweight (body condition score ≥ 6/9) client-owned insulin-treated diabetic cats, randomized either to caloric restriction (intervention, 32; target approximately 2% weekly weight loss) or body weight maintenance (control, 40). Methods: All cats received a novel therapeutic diabetic diet, suitable for weight reduction, for 12 weeks (%metabolizable energy [protein/fat/nitrogen-free extract]: dry [49.4/24/26.6]; wet [63.2/25.3/11.5]). Physical examination, serum biochemistry, home blood glucose curves (BGC), diabetic clinical score, and quality of life questionnaires were performed on weeks: −1, 4, 8, and 12. Insulin dose was recorded and glycemic variability (SD of BGC) was calculated. Induction of diabetic remission was the primary outcome measure. Data were analyzed using regression and linear mixed models. Results: By week 12, intervention had 2.1 times higher probability of remission (16/32) compared with controls (12/40, P = .04). Weight loss was 7.2% (95% confidence interval [CI], 5.7-8.7) for the intervention versus 2.7% (95% CI, 1.3-4.1, P < .001) for controls. For cats not achieving remission, glycemic variability decreased 45% (95% CI, 26-65) and 7% (95% CI, 16-21) for intervention and control cats, respectively (P = .01), insulin-dose decreased by 36% (95% CI, 2-70) for intervention and increased 28% (95% CI, 3-53, P = .004) for controls. Conclusions and clinical importance: Caloric restriction, using a therapeutic diabetic diet suitable for weight reduction increased the probability of remission and improved glycemic control in overweight diabetic cats.

Background: Ionized calcium concentration ([iCa]) is more sensitive for detecting calcium disturbances than serum total calcium concentration but literature on ionized hypercalcemia in cats is limited. Urolithiasis is a possible adverse consequence of hypercalcemia. Hypothesis/Objectives: To describe clinical details of diagnoses associated with ionized hypercalcemia in cats and association with urolithiasis. Animals: Cats (238) seen between 2009 and 2019 at a referral hospital with [iCa] above the normal reference interval. Methods: Observational cross-sectional study. Signalment, serum biochemical and imaging findings were reviewed for cats with ionized hypercalcemia considered to be clinically relevant (>1.41 mmol/L). Data were summarized by cause of hypercalcemia (i.e., diagnosis). Results: Diagnoses for the 238 cats with [iCa] >1.41 mmol/L included: acute kidney injury (AKI; 13%), malignancy-associated (10.1%), idiopathic hypercalcemia (IHC; 10.1%), chronic kidney disease/renal diet-associated (8.4%), iatrogenic (5.5%), primary hyperparathyroidism (2.1%), vitamin D toxicity (2.1%) and granulomatous disease (1.7%). In 112 cases (47.1%), no cause for ionized hypercalcemia could be determined (n = 95), hypercalcemia was transient (n = 12), or the cat was juvenile (<1 year; n = 5). Urolithiasis was identified in 83.3% of AKI, 72.7% of iatrogenic, 61.1% of CKD/renal diet-associated and 50% of IHC cases that were imaged (<50% for other diagnoses). Diagnoses with a high proportion of concurrent total hypercalcemia included primary hyperparathyroidism (100%), vitamin D toxicity (100%), malignancy-associated (71.4%), granulomatous disease (66.7%) and IHC (65.2%). Conclusions and Clinical Importance: Ionized hypercalcemia was most commonly associated with kidney diseases, neoplasia or IHC. The proportion of urolithiasis cases varied by diagnosis.