2 Mar 2021
Alex Gough reviews more companion animal research, including a study on CT urethrography in female dogs.
Alex Gough
Job Title
Thyroid carcinoma is a relatively common malignancy in dogs, and is difficult to treat due to its location next to vital structures and its local invasion.
Thyroidectomy and radiotherapy are often employed to treat this condition, but are not always possible or available.
Sheppard-Olivares et al1 performed a retrospective study to assess the use of toceranib in the management of the condition, both before and after other treatments.
A total of 26 dogs were identified in the record that had not had previous treatment, and 16 dogs had received prior therapy.
In total, 88% of the dogs that had not received previous treatment – and 75% of the dogs that had – experienced a clinical benefit.
The median overall survival time was 563 days for dogs that had not had prior treatment and 1,082 days for those that had.
Dogs that were asymptomatic at the time of diagnosis and naive to treatment had a poorer prognosis than dogs that had been previously treated.
Minimal adverse effects of the toceranib treatment were noted.
Biological variation refers to the variation in the values of a measurement that are due to chance interactions with physiology and environment.
It can refer to the variation in means and ranges of values between different individuals within a population, or the variation within an individual over time.
Prieto et al2 performed a prospective study to evaluate the biologic variation of symmetric dimethylarginine (SDMA) in healthy cats.
Coefficients of variation (CV, standard deviation/mean) was calculated for the between-individual, within-individual and analytical variation. These results were used to calculate the index of individuality (the ratio of the within to between individual variation) and reference change value (the minimum change between two values that is likely to be clinically significant).
SDMA was considered to have an intermediate index of individuality, while creatinine had a high index of individuality.
The authors concluded population‑based reference intervals could be used to assess SDMA results, but creatinine was better assessed with reference change values. They also concluded that clinicians should consider biologic variation when interpreting changes in biochemical results.
Although the world’s attention is on the coronavirus pandemic, antimicrobial resistance is another health crisis that continues.
De Jong et al3 reported results from the ComPath project, which is dedicated to monitoring antimicrobial resistance in dogs and cats.
Minimal inhibitory concentrations were determined for common antibiotics. A total of 1,676 pathogens isolated from nontreated animals with skin wound or ear infections in 2013-14 were included in the study.
Staphylococcus pseudintermedius was the most commonly isolated pathogen in dogs, followed by Streptococcus, Pseudomonas and Escherichia coli.
In cats, Pasteurella and Staphylococcus were isolated most commonly.
Resistance rates were greater than 90% for beta-lactams in Staphylococcus aureus. The mecA gene for resistance was present in 31% of S aureus cases. E coli isolates were also highly resistant to beta-lactams.
However, overall antimicrobial resistance in cutaneous and aural pathogens was low to moderate.
Traumatic brain injury (TBI) is a common problem in dogs and cats, for example associated with road traffic incidents.
Wyatt et al4 performed a retrospective study to assess whether CT findings help assess short‑term prognosis in dogs with TBI. A total of 40 dogs were included in the study.
The CT findings were graded from I, representing normal brain parenchyma, to VI, in which bilateral brainstem lesions were seen.
In total, 75% of dogs survived to discharge. A total of 18% suffered seizures, but no association existed between survival and seizures.
No imaging features correlated with outcome, and the study failed to identify CT features that had prognostic significance.
The authors concluded CT may not be useful for assessing prognosis in TBI, but further studies with larger populations are needed.
Areas in which large numbers of cats are housed, such as rescue centres and kitten nurseries, have the potential to have high rates of respiratory diseases.
Jaynes et al5 performed a study to evaluate the effect of UV germicidal irradiation of the air on the incidence of upper respiratory tract infections in kittens in a nursery setting.
The incidence of respiratory diseases before and after the UV systems were installed was compared. An 87% decrease in cases per 100 kittens was seen after the installation of the germicidal systems.
The authors concluded airborne transmission of respiratory pathogens in kittens may be more important than was previously realised. Germicidal UV systems may help reduce respiratory infection incidence, but further research is needed.
Suture cassettes are thought to be associated with bacterial contamination because of multiple usage. However, they are cheaper than separately packaged sutures and, therefore, are often used by high-quality, high-volume spay/neuter (HQHVSN) vets.
Comroe and Roush6 collected absorbable suture samples from suture cassettes in 25 HQHVSN clinics. Of them, 17 were positive for microbial growth and 11 clinics had at least one positive sample.
The authors concluded although an increase in infection by vets using suture cassettes was not reported, it is likely some contaminated suture is being used during these surgeries.
Retrograde urethrography is a useful technique to assess for urethral lesions, and CT urethrography with a power injector has recently been reported in male dogs.
Kang et al7 performed a prospective study to assess the use of this technique in females. Six healthy, entire female beagles were included in the study.
The urethral flexure was found to be related to intrapelvic bladder position. The urethral diameter was significantly different at the vesicourethral junction in empty and distended bladders.
The authors noted a partly intrapelvic urinary bladder may be seen in clinically normal female dogs, and this can cause narrowing of the urethra.
Urethral narrowing should, therefore, be interpreted cautiously in the presence of an intrapelvic bladder.
