14 Sept 2023
Alex Gough MA, VetMB, CertSAM, CertVC, PGCert(Neuroimaging), MRCVS looks at a trial comparing GI bleeding in dogs with a form of prednisone and a placebo, plus other studies, in his latest Research Review.
Alex Gough
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Image: © Anna Goroshnikova / Adobe Stock
Glucocorticoid treatment such as prednisone can be associated with gastrointestinal (GI) ulceration and bleeding – especially when given at high doses. Omeprazole and probiotics have been proposed as ways of preventing or reducing steroid-associated gastric bleeding.
Rak et al1 performed a double-blind randomised trial to compare GI bleeding in dogs given a placebo with those given prednisone either alone, with omeprazole or with probiotics. A total of 24 healthy dogs were included in the study. Clinical signs and mucosal lesion scores assessed with GI endoscopy were recorded on days 1, 14 and 28. In total, 33 episodes of diarrhoea were recorded – 19 of these being in the prednisone plus omeprazole group. The gastric mucosal lesion scores differed over time and among treatment groups, with scores increasing over time for all prednisone groups.
The scores for the prednisone alone and prednisone with probiotics differed significantly from placebo, but the omeprazole plus prednisone group did not. The authors concluded that in this study, prednisone-induced gastric bleeding and omeprazole reduced this adverse effect, but probiotics did not.
Spinal disease can also be associated with GI ulceration and omeprazole is often recommended to counter this. Mehra et al2 performed a double-blind placebo-controlled trial to evaluate the hypothesis that omeprazole does not decrease the frequency of GI complications associated with acute thoracolumbar intervertebral disc extrusion. A total of 37 dogs undergoing hemilaminectomy for acute thoracolumbar disc extrusion were included in the study. Dogs were given placebo or omeprazole for five days while they were hospitalised, and the presence of GI signs was recorded.
Biochemistry and haematology tests were performed during hospitalisation, and during re-evaluations two and four weeks later. A total of 50% of dogs in the omeprazole group developed GI signs compared to 41% in the placebo group – this was not statistically significant. Diarrhoea was common, but only one case of haematochezia was seen in each group and no cases of melaena were seen. Faecal occult blood tests were more likely to be positive in dogs with GI signs.
The authors noted that in this study, short-term use of omeprazole was not associated with a decrease in GI clinical signs.
Problems with inappropriate use of feline litter boxes and associated elimination issues, such as house soiling, can be problematic and distressing for owners, and may potentially lead to rehoming or euthanasia of cats exhibiting this behaviour.
Mikkola et al3 performed a survey of owners to identify risk factors associated with feline litter box issues. A total of 3,049 privately owned cats were included in the study. A validated survey was given to a convenience sample of owners who had 138 statements related to cat behaviour and also questions on the background of the cat and health status.
House soiling and litter box fussiness were identified as problems. Fearful cats were more likely to have these issues than non-fearful cats. Being male, intact and less sociable to other cats was associated with soiling in the house, while older age was associated with litter box fussiness. The authors concluded that these results may help in finding new solutions to litter box problems.
Protein-losing enteropathy (PLE) is a serious condition in dogs that when untreated can lead to high levels of morbidity, mortality and undesirable sequelae. Recommended treatment usually revolves around diet and immunosuppressive therapy such as glucocorticoids. However, the evidence for a low-fat diet as a treatment for dogs with PLE combined with lymphangiectasia is limited.
Myers et al4 performed a prospective observational cohort study of 14 dogs with presumed PLE and evidence of lymphangiectasia on ultrasound. Dogs were given low-fat diets, and prednisone was added if an insufficient response to dietary treatment was obtained. The dogs were followed for six months, with clinical scores at four time points and an ultrasound examination at the end.
In total, 11 of the 14 dogs were considered to be in clinical remission at the study end date – 6 of which were treated with a low-fat diet only and 5 of which were treated with a low-fat diet and prednisone. The diet-only group had a significant reduction in clinical enteropathy scoring and a significant increase in serum albumin within two weeks of starting dietary therapy. In total, 4 of the 11 dogs had ultrasonographic evidence of improvement.
The authors concluded that low-fat diet can be effective as a single therapy for PLE with lymphangiectasia.
It is common for cats with systemic disease to have ocular involvement, but antemortem histopathological examination of the eye in these situations is unusual since enucleation is rarely required.
Wronski et al5 aimed to record the gross, histological and immunohistochemical findings of ocular lesions in cats that had undergone postmortem examination – particularly focusing on those cases that had systemic disease. A total of 849 eyes from 428 cats were evaluated.
In total, 29 per cent of cases had histopathological abnormalities – 41% of which were inflammatory, 32% neoplastic, 19% degenerative and 8 per cent metabolic or vascular. One-third of cases had grossly visible changes. FeLV, FIP virus and Cryptococcus were the most important infectious agents associated with ocular disease, leading to pathologies such as uveitis and optic neuritis.
The authors noted that ocular lesions frequently result from systemic infections in cats, and recommended that gross and histopathological examination of the eye is carried out at postmortem where a suspicion exists that an infectious agent is associated with death.
Absence seizures are often reported in humans, and are characterised by sudden periods of inactivity, unresponsiveness and staring. They are rarely reported in dogs, but as absence seizures are hard to distinguish from focal seizures, Chawner et al6 grouped all non-generalised tonic-clonic seizures (GTCS) together in their retrospective study, which aimed to evaluate the prevalence of non-GTCS and the distribution of seizure type in a referral population.
Diagnosis was from history and where available from electroencephalography (EEG). A total of 528 cases with seizures were included in the study.
In total, 53% to 63% of seizures were described as generalised tonic-clonic, 9% to 15% as GCTS with additional events, and 29% to 35% as suspected non-GCTS. Absence seizures were confirmed in 12 of 44 EEGs – 5 of which had previously had GCTS and 7 of which had not.
The authors suggested that non-GCTS may be common, with around one-third of seizure cases in a referral population presenting with non-GCTS signs. Prospective studies using EEG will help confirm these findings, and awareness of these seizure types may improve diagnosis and potential treatment options.
Implants used in orthopaedic surgery are significant sources of infection, and this can necessitate prolonged antibiotic usage (which can lead to antibiotic resistance) or even invasive surgery to remove the implants.
Ziabka et al7 performed in vitro and in vivo studies on titanium alloy implants that had antibacterial coatings of silver, copper and zinc nanoparticles. The implant coatings were tested against Gram-positive and Gram-negative bacteria, and pathogenic yeast and with human osteosarcoma cell lines. The implants were then tested in six canine patients undergoing tibial plateau levelling osteotomy.
Radiology was carried out after three months to assess the success of the procedure, and histopathological examination of the tissue to evaluate regeneration was performed. The silver nanoparticles were found to have the best antibacterial effect. An increased concentration of the metallic additives was associated with an increased toxic effect – especially higher concentrations of the silver nanoparticles. However, low-dose silver nanoparticles appeared to help accelerate the bone healing process. Good tissue repair was achieved.
Antibacterial-coated implants may help reduce the rate of infection in orthopaedic operations.
