29 Sept 2020
Alex Gough presents the latest in his Research Review articles, with the latest companion animal research for September 2020.
Alex Gough
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Image © Mary Swift / Adobe Stock
Cardiomyopathies are common diseases in cats, and it is well known that hypertrophic cardiomyopathy is associated with arrhythmias.
Ferasin et al1 documented the presence of arrhythmias in 13 cats with other forms of hypertrophic cardiomyopathy – namely restrictive cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy and non‑specific cardiomyopathy.
The cats underwent 24-hour ambulatory (Holter) electrocardiography. Eight of the cats were suffering from congestive heart failure at the time of presentation, one was suffering from recurrent episodes of syncope and four were asymptomatic.
The slowest mean heart rate was in a cat that had third-degree atrioventricular block, while the fastest was in a cat with atrial fibrillation. All 13 cats had cardiac arrhythmias despite 8 of them having normal resting ECGs.
The presence of heart failure appeared to have no effect on the resting heart rate, but none of the cats had any periods of sinus arrhythmia.
Mast cell tumours are common and problematic neoplasms, with a range of clinical outcomes that can be hard to predict.
Gill et al2 performed a retrospective study to assess prognostic indicators in dogs with SC mast cell tumours that were treated with surgery alone. A total of 43 dogs were included in the study, and had their progression-free survival, disease-free intervals and overall survival calculated.
In total, 42 dogs had grade two mast cell tumours by the Patnaik system and 22 had low‑grade tumours by the two-tier grading system.
The median progression-free survival time was about four years and the median disease‑free interval was not reached, so was more than five years.
Argyrophilic nucleolar organiser regions (AgNORs), proliferating cell nuclear antigen and mitotic index were negative prognostic indicators for progression‑free survival, and Ki-67, proliferating cell nuclear antigen and mitotic index were negative prognostic indicators for disease‑free interval, using univariate analysis.
For multivariate analysis, AgNORs were still negative prognostic indicators.
The authors concluded some proliferation indices – particularly AgNORs – may be useful for prognostic information, but that most SC mast cell tumours are low to intermediate grade, and have very good outcomes with surgery alone.
Inflammation and swelling of the pancreas during episodes of pancreatitis can lead to extrahepatic bile duct obstruction.
Palermo et al3 performed a retrospective review of 45 dogs with suspected extrahepatic bile duct obstruction secondary to pancreatitis. The median survival time was 241 days, with 34 dogs surviving to discharge.
Older dogs with azotaemia at presentation were at a much greater hazard of dying. Absence of ultrasonographically determined gall bladder distension was also associated with a much greater hazard of dying compared to those in which the gall bladder was considered non-distended, and higher body temperature at admission was a negative prognostic indicator.
These factors can be used to help ascertain prognosis for this condition.
It has been known for some time that grapes and raisins can be toxic to dogs and cause acute kidney injury.
Schweighauser et al4 performed a retrospective study to compare 15 dogs with grape and raisin toxicity with 74 control dogs.
All the dogs with grape or raisin toxicity had severe acute kidney injury, while 11 of the dogs also had neurological signs referable to the forebrain, cerebellum or vestibular system. These signs were not associated with the grade of kidney injury or the blood pressure.
Eight dogs survived to discharge. Five dogs had a complete neurological recovery. Four dogs that did not recover underwent neuropathological examination of the CNS, which did not identify any structural abnormality.
The authors noted severe CNS signs may dominate the early clinical picture in grape and raisin toxicity, but these signs may be reversible.
Neutering of bitches is an invasive procedure, with some small risks associated, even when performed laparoscopically.
Verpaalen et al5 investigated a less invasive way of performing neutering, using ultrasonically and laparoscopically guided microwave ablation of the ovaries.
Two trials were included in the study.
In the first trial, 13 dogs had their ovaries removed at routine laparotomy. The ovaries then underwent microwave ablation for two different lengths of times – 60 and 90 seconds. All the ovaries that underwent the longer microwave time were completely ablated on histological examination.
In the second trial, 9 dogs underwent the longer microwave ablation with the ovaries in situ. Ultrasound-guided microwave ablation was found to be unfeasible. Laparoscopically guided microwave ablation was performed followed by routine laparoscopic oophorectomy. Of 17 ovaries treated this way, 12 were completely ablated.
The authors noted laparoscopic-guided microwave ablation was feasible, safe and effective for ablation of ovaries in normal bitches.
Various schemes exist around the world for the assessment of hip joint quality to reduce the incidence of hip disease in the various breeds in which it is common.
Haney et al6 performed a retrospective study of the PennHIP distraction index (DI) and Orthopaedic Foundation for Animals (OFA) hip joint scores to assess whether these schemes could improve joint quality in a population and to look for factors associated with hip joint quality in purpose-bred detection dogs.
A total of 569 Labrador retrievers and 46 Labrador retriever-cross-German wirehaired pointers were included in the study.
From 2000‑14, the hips were evaluated using the OFA scores only, but from 2015 the PennHIP and OFA evaluations were used to select breeding stock.
No improvement occurred in hip joint quality in the population when using the OFA evaluation alone, but when the PennHIP evaluation was added, hip joint quality scores were found to improve significantly. Sex and age were associated with the DI values.
The authors concluded the addition of PennHIP DI scoring to the OA evaluation when selecting breeding stock led to a significant improvement in hip joint quality.
The veterinary profession has a well‑recognised problem with mental health, but within the profession some groups may be even more prone to psychological distress.
Witte et al7 performed a study of lesbian, gay, bisexual, transgender, queer, questioning and asexual (LGBTQ+) veterinary professionals and students to compare the levels of negative mental health with the profession in general.
A total of 440 LGBTQ+ veterinary professionals and students from the UK and US took part in the web-based questionnaire study.
Non‑heterosexual cis men, non‑heterosexual cis women, and transgender and non‑binary individuals had higher prevalences of suicidal ideation and attempted suicide than the wider profession.
Professionals reported their work climates were more welcoming than did the students, although the students had more access to resources and policies. However, the variables associated with a welcoming or unwelcoming climate were more important than access to LGBTQ+ policies.
The authors suggested more effort is needed to improve the climate towards LGBTQ+ staff and students in veterinary workplaces and colleges.
