26 Sept 2023
Chiari-like malformation, suture knots, cancer detection and feline infectious peritonitis are among the topics under the microscope in Alex Gough’s latest Research Review for Vet Times.
Alex Gough
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Photo by Pranidchakan Boonrom / Pexels
Failure of suture knots is a major cause of postoperative morbidity and mortality. Whyte et al1 performed a study to assess whether axial twisting has an impact on the maximum load to knot failure – 525 knots comprising 15 samples each of 7 different sizes and/or types of suture were used in the study.
A starting square knot was made and the following ending square knot had 0, 1, 4 or 10 twists. They were then loaded to test for failure, and video footage and gross evaluation was used to assess the mode of failure. The maximum load at failure was lower in knots with loops containing more twists in some suture size/types. Generally, sutures with 4 or 10 twists were more likely to fail than sutures with zero twists.
The authors concluded that an increased number of twists can decrease the maximum load to failure of a knot – especially with larger suture sizes.
Chiari-like malformation is very common in cavalier King Charles spaniels (CKCS) and can lead to the formation of a syringomyelia, which can cause distressing clinical signs such as persistent scratching. Cole et al2 performed a study to assess the impact of Chiari-like malformation on hearing loss in this breed, using brainstem auditory-evoked response (BAER) latency testing.
The aim of the study was to establish breed-specific ranges for the BAER test, and to see whether the BAER results were related to the grade of Chiari malformation. Twenty CKCS whose owners did not consider them to have hearing problems were included in the study. Computed tomography of the middle ear, magnetic resonance imaging to assess grade of Chiari-like malformation and BAER testing were carried out. All the dogs had some degree of Chiari-like malformation and all had abnormalities on BAER testing.
The authors concluded that Chiari-like malformation affects the results of BAER testing, but not necessarily in a predictable way.
It is often recommended that bitches are neutered at the same time as performing a caesarean section for a variety of reasons relating to population control, reduction of passing on undesirable genetic traits and the welfare of the individual animal, since further pregnancies may also require caesarean sections. However, concerns exist about an increased morbidity caused by neutering at the same time as caesarean sections, as well as the possibility of reduced mothering ability.
Guest et al3 performed a study to compare maternal mortality and morbidity and mothering abilities between bitches that underwent caesarean sections alone or caesarean sections plus ovariohysterectomy (OVH) – 125 bitches were included in this retrospective study, 80 that underwent C-section alone and 45 that underwent caesarean sections plus OVH.
No differences were found in variables such as anaesthesia duration, intraoperative and postoperative complications, mothering ability or puppy survival to weaning.
The surgery time was longer in dogs that underwent OVH and in these cases, a longer time from delivery to nursing persisted. Of bitches available to follow up, all survived, although the ones that underwent OVH were perceived as suffering from more postoperative pain.
The authors concluded that it is reasonable to perform OVH at the same time as caesarean section, but additional analgesia should be considered.
It is well known that dogs have a highly sensitive sense of smell and people have used this in various roles over history, such as tracking prey and missing people, and detecting explosives and drugs. More recently, dogs have been used to detect cancer in humans.
Malone et al4 performed a study to assess whether dogs could be trained to detect cancer in other dogs.
Saliva was collected from 139 dogs with malignant cancer and 161 healthy controls. Six dogs were trained to discriminate between the samples with and without cancer. Samples not used during training were used for testing. The trained dogs were able to distinguish between the samples from dogs with and without cancer with a sensitivity of 90% and a specificity of 98%.
This preliminary trial suggests that dogs can detect differences between saliva samples from dogs with and without cancer.
Canine cutaneous epitheliotropic T-cell lymphoma is an uncommon malignant skin cancer of dogs. It has a variety of clinical and histopathological presentations. Data on prognostic indicators are lacking.
Dettwiler et al5 performed a retrospective study of the clinical and histopathological findings of 176 cases of this condition, and their clinical outcomes. A total of 131 cases had signs of erythema, 108 had crusting and 102 had scaling. Haired skin, lip, nasal planum and paw pads were the most common sites affected. The median survival time was only 95 days, but the range was one to 850 days.
Chemotherapy increased median survival time approximately four times, and prednisone approximately two times. Clinical signs of haired skin involvement, erosions or ulcers, nodules and crusting were associated with worse outcomes. Histopathological infiltration of the panniculus was also a poor prognostic indicator, as were mitotic count, cell diameter and nuclear diameter. These findings help inform clinicians about factors associated with outcome in epitheliotropic T-cell lymphoma.
Autoimmune encephalitis is encountered commonly in humans, and can be associated with antibodies against extracellular neuronal proteins. Antibodies against leucine-rich glioma-inactivated 1 (LGI1) is one of the most common forms and has also been described in cats with limbic encephalitis.
Glantschnigg-Eisl et al6 described 32 cats with autoimmune encephalitis, which tested positive for voltage gated potassium-channel (VGKC) antibodies. Brain imaging and cerebrospinal fluid analysis were often unremarkable – 81% of these cases had LGI1 antibodies, 83% of cats had signs of focal seizures, most of them in clusters and most with interictal behavioural changes. No pathognomic seizure types were seen in cats, unlike in humans. Cats that reached one year post-onset tended to have good seizure control and quality of life.
The authors suggested that LGI1 auto-antibodies are an important cause of limbic epilepsy in cats, and more research would be useful to ascertain optimal treatments.
Feline infectious peritonitis (FIP) is difficult to treat in cats and is usually fatal. However, GS-441524 has been reported to successfully treat the condition. Green et al7 described a study in which cats with FIP were treated with a combination of GS-4412524 given orally and its prodrug remdesivir given by injection. A total of 32 cats with effusive or non-effusive FIP were included in the study – 87.5% of cats showed a clinical response, and 81.3% of cats were still alive and in remission at the end of 12 weeks’ treatment. Different protocols were found to be successful and different presentations of FIP, including those with ocular and neurological involvement, were treated.
Use of some of the drugs mentioned in this article is under the veterinary medicine cascade.
