8 Dec 2020
Alex Gough MA, VetMB, CertSAM, CertVC, PGCert(Neuroimaging), MRCVS is back with another round up of veterinary studies in this Research Review from the pages of Vet Times.
Alex Gough
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Image: kkolosov / Pixabay
Vitamin D is necessary to support a variety of roles in the body, and while it is most known for its association with bone metabolism, it is also important to the function of the immune system.
Allison et al1 performed a study to assess the association of serum vitamin D with immune function in dogs. Ten apparently healthy shelter dogs housed for seven or more days and 10 matched control dogs were included in the study. Serum 25-hydroxyvitamin D (25[OH]D), the major vitamin D metabolite, was measured along with various immune markers.
No significant difference in 25(OH)D level existed between the control and shelter dogs. However, evidence of immune dysregulation in the shelter dogs existed, and associations between the 25(OH)D concentration and immune function parameters were found.
Maropitant is a neurokinin-1 antagonist that has a licence in the UK for management of emesis. It has been postulated that maropitant has analgesic – as well as anti-emetic – effects modulated by its action in blocking Substance P, which has roles in inflammation and nociception, as well as emesis.
Kinobe and Mikaye2 performed a review of the properties of neurokinin-1 antagonists, and then a systematic review and meta-analysis on the effects of maropitant. In total, 14 studies were identified that met the authors’ inclusion criteria. These showed that maropitant had a sparing effect on inhalation anaesthesia.
However, no evidence existed that maropitant helped with pain, nor had any effect on leukocyte infiltration in inflammatory conditions. The authors concluded that although maropitant can reduce the minimum alveolar concentration for isoflurane and sevoflurane in surgical procedures, no evidence exists yet for a benefit of using this drug as an analgesic or anti-inflammatory.
Various canine breeds are predisposed to immune-mediated and degenerative inherited polyneuropathies.
Jahns et al3 described a case series of seven young Siberian huskies with degenerative and inflammatory polyneuropathies. These cases were categorised into one of four groups depending on their characteristics.
One group of two dogs exhibited a slowly progressive laryngeal paralysis and megaoesophagus, which was caused pathologically by a primary axonal degeneration. One group of two dogs showed a slowly progressive polyneuropathy without megaoesophagus or laryngeal paralysis, again caused by primary axonal degeneration.
One group of two dogs had an acute inflammatory demyelinating neuropathy, which caused problems with sensory, motor and autonomic pathways, and the final dog in the series had a sensory neuropathy caused by ganglioradiculitis.
A hereditary basis for this group of diseases was assumed, but genetic testing for mutations in genes known to cause polyneuropathies in other dogs was negative.
The US Animal Poison Center is one of the American equivalents of the UK’s Veterinary Poisons Information Service, giving advice on animal intoxications.
Swirski et al4 described the data from telephone calls to the centre regarding suspected companion animal exposures to toxins and other hazardous substances over a 10-year period. More than 240,000 poisoning events were logged in the 10-year period, with 86% involving dogs and 14% involving cats.
The most common toxins reported for dogs were human medicines, foods and pesticides, while for cats the most common toxins reported were human medicines, plants and veterinary medicines. The most commonly reported toxin for dogs was chocolate and for cats, lily plants. The most toxic substances were fluorouracil in dogs, with a mortality rate of 62.5%; and bifenthrin in cats, with a mortality rate of 66.7%.
Paracetamol (or acetaminophen as our US colleagues call it) is licensed in combination with codeine for analgesia in dogs in the UK. Its popularity as an analgesic has gone in and out of fashion.
Budsberg et al5 performed a blinded crossover study to compare the effects of an orally administered paracetamol-codeine combination with carprofen in seven dogs in which synovitis had been experimentally induced. Outcome measures were ground reaction forces and clinical lameness, before and at a number of time points after induction of lameness.
Significantly higher lameness scores and lower ground reaction forces were seen during treatment with paracetamol-codeine than with carprofen at several time points. The authors concluded that carprofen was more effective than paracetamol-codeine in treating experimentally induced lameness in these dogs.
Hypoadrenocorticism can present with a variety of clinical signs in dogs, and one of these is gastrointestinal (GI) disease. Hypoadrenocorticism in chronic GI disease may be under-recognised.
Hauck et al6 performed a multicentre prevalence study to assess the prevalence of hypoadrenocorticism in dogs with signs of GI disease. A total of 151 dogs with chronic GI signs had a basal cortisol performed, and an adrenocorticotropic hormone (ACTH) stimulation test was performed if this result was low.
In total, 53% of dogs had a low basal cortisol concentration. However, only 4% had hypoadrenocorticism diagnosed after an ACTH stimulation test. No difference was noted in clinicopathological variables between the dogs with and without hypoadrenocorticism. None of these cases had hyperkalaemia or hyponatraemia.
The authors concluded the prevalence of hypoadrenocorticism in dogs with signs of GI disease is higher than in the general population, and testing for adrenal function should be part of the standard work-up in these cases.
Although ultrasonography is generally considered a more accurate method of estimating cardiac dimensions than radiography, x-rays can be useful when echocardiography is not available.
Vezzosi et al7 performed a retrospective observational study to assess the vertebral left atrial size (VLAS), a method of quantifying left atrial size in dogs. The radiographs of 80 adult dogs were evaluated and the left atrial size was determined by echocardiographic left atrial to aorta ratios.
The median value of the VLAS was 1.9, and the reference interval was 1.4 to 2.2. There was a positive correlation between VLAS and vertebral heart score measurements. There were excellent intraobserver and interobserver agreements for VLAS.
The authors concluded this measure is a repeatable method for quantifying left atrial size in healthy dogs. However, further research is needed to ascertain its value in dogs with clinical disease.
