21 Nov 2023
In his latest research review, Alex Gough looks at canine distichiasis, a retrospective study of cats treated with tranexamic acid and epsilon aminocaproic acid, post-neutering weight gain, and more…
Alex Gough
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Mast cell tumours are problematic neoplasias commonly encountered in dogs. They have a wide range of behaviours and outcomes, and a large body of literature exists on the disease. However, previous studies often combine different tumour grades, clinical stages and treatments, which can make their results harder to interpret.
Burge et al1 performed a retrospective study aimed at examining the findings in dogs with high-grade, stage 2, cutaneous mast cell tumours that were treated with surgery and chemotherapy, with or without radiotherapy. A total of 17 dogs were included in the study. The median survival time was 259 days, and poor prognostic indicators included ulceration, local recurrence and location on the head. However, size of tumour, type of chemotherapy, use of radiotherapy, mitotic count and involvement of local lymph nodes were not associated with survival.
The authors suggested that these results can be used in future research to compare treatments in this subpopulation of dogs with mast cell tumours.
Antifibrinolytic drugs such as tranexamic acid (TXA) and epsilon aminocaproic acid (EACA) are used to improve haemostasis in a variety of conditions, but little information exists on their use in cats.
Wahldén et al2 performed a retrospective study of cats treated with TXA or EACA – 35 cats were included in the study, with 86% receiving TXA and 14% receiving EACA. In 54% of cases, the reason for use of the fibrinolytic drug was non-traumatic haemorrhage, with 17% for traumatic haemorrhage and 11% for elective surgery. Just more than half of the cats survived to discharge, 20% of cases had suspected adverse effects and, of these, only 29% survived to discharge.
The authors noted a marked variation existed in dose, dosing interval and duration of treatment between patients, with no standardised treatment regime found. The authors suggested their study can be used as a basis for future prospective studies, and it will be important to elucidate the association between use of the drugs and potentially serious adverse effects.
Tick paralysis is a parasite-borne neurological disease of dogs and cats often encountered in Australia. Ireland et al3 performed a retrospective study to ascertain whether the introduction of a new generation of prophylactic acaricides, including isoxazolines and imidacloprid/flumethrin collars, had affected the incidence of the condition.
More than 10,000 dogs and more than 3,600 cats were included in the study, which involved two emergency veterinary hospitals in south-east Queensland. Data were analysed both graphically and numerically, and interrupted time series analyses were performed.
A reduction in cases of around 55% in dogs and 44% in cats was found to correspond with the introduction of the new generation of acaricides.
The authors concluded that a significant reduction occurred in the incidence of tick paralysis cases in the population in their study, which was associated temporally with the release of the new prophylactic treatments.
Distichiasis is a condition in which extra eyelashes are located in the wrong place on the margin of the eyelid. Jondeau et al4 performed a retrospective study of medical records in an ophthalmology speciality clinic to report the epidemiology and importance of canine distichiasis.
A total of 291 dogs were included in the study. The prevalence of distichiasis was 5.5% overall, but with English bulldogs having a prevalence of 35.2%, and American cocker spaniels 19.4%. Brachycephalic dogs had a higher prevalence of the condition compared to other breeds. Short-haired dogs were also over-represented. Roughly two-thirds of cases were bilateral.
Distichiasis was not considered to be irritating in 85% of dogs with the condition, but in those that did have clinical signs, 39% had corneal ulceration, some of which were deep stromal ulcers.
The authors concluded that distichiasis is often non-harmful in dogs, but can be a cause of severe clinical signs and that brachycephalic breeds are predisposed to the condition.
Laparoscopic neutering of bitches is becoming increasingly more common – particularly due to its perceived reduction in discomfort for the patients. However, some questions remain over the best way to perform the procedure – particularly with regards to sparing the ovaries.
Owen et al5 performed a questionnaire-based study to look at the outcomes after laparoscopic ovary-sparing spay (LapOSS) or laparoscopic ovariectomy (LapOVE) – 33 dogs were included in the study, which had a mean follow up time of around four years. None of the dogs developed stump pyometra in this time. One dog in the LapOSS group developed a mammary tumour and two developed malignant neoplasia not associated with the reproductive system. In the LapOVE group two dogs developed malignant neoplasia.
The authors concluded that the laparoscopic-assisted ovary-sparing spay procedure is safe and effective, and does not appear to increase the risk of pyometra. However, they noted that owners must be made aware of the consequences of continued seasons and gonadal hormone retention.
One problem with neutering is its association with weight gain. Benka et al6 performed a retrospective cohort study to examine the risk of becoming overweight or obese after neutering, and to look at whether age of neutering affected the outcome with respect to body condition score. In this very large study, 155,199 dogs were included. Neutering increased the risk of being overweight or obese compared to intact dogs. It was also noted that the hazard ratios for obesity and being overweight were larger in neutered males than neutered females.
Increasing breed size increased the risk of becoming overweight or obese. Neutering at one year of age lowered the risk of obesity/being overweight compared to later neutering, but the risk of obesity/being overweight when neutering was performed at six months compared to a year varied by breed.
The authors noted that vets can help prevent obesity and being overweight in dogs and cats, and the information in this study can help guide owners with decision-making regarding neutering of their pets.
Identifying myxomatous mitral valve disease in dogs is important to allow decisions to be made about further investigations and the timing of treatment. Galectin-3 is a cardiac biomarker used in humans to identify heart failure, but its use in dogs has not been investigated.
Kim et al7 performed a prospective case-control study that included 10 healthy dogs and 30 dogs with mitral valve disease. Plasma galectin-3, inflammatory cytokines, other biomarkers and echocardiographic investigations were performed.
The plasma galectin-3 concentration was significantly higher in dogs with myxomatous mitral valve disease than the healthy controls. Galectin-3 and age could predict the presence of mitral valve disease with an accuracy of 90%.
The authors concluded that plasma galectin-3 can be used to detect mitral valve disease, but it does not appear to be helpful in differentiating stages of the disease.
