Postattenuation neurologic signs after surgical attenuation of congenital portosystemic shunts in dogs: A review.

The development of postattenuation neurologic signs (PANS) is a poorly understood and potentially devastating complication after surgical attenuation of congenital portosystemic shunts in dogs. Postattenuation neurologic signs include seizures but also more subtle neurologic signs such as depression, behavioral changes, tremors, and twitching. They most commonly occur within 7 days postoperatively and are typically unrelated to hyperammonemia, hypoglycemia, or electrolyte disturbances. This narrative review summarizes the findings of 50 publications from 1988-2020 that report occurrence of PANS. While most published reports included only dogs affected by postattenuation seizures (PAS), others included dogs with any form of PANS. Overall, PANS (including PAS) affected 1.6%-27.3% of dogs, whereas incidence of PAS ranged from 0%-18.2%. The etiology of PANS remains unknown; however, several theories have been proposed. Risk factors include preoperative hepatic encephalopathy, increasing age, and possibly certain breeds and extrahepatic shunt morphology. There is increasing evidence that prophylactic antiepileptic drugs do not prevent PANS. Treatment is centered around controlling neurologic signs with antiepileptic drugs and providing supportive intensive care. The 30-day survival rate in studies that included a minimum of four dogs affected by PANS was 0%-100% (median, 50.0%) and 0%-75.0% (median, 37.5%) for those with PAS. Mortality associated with PANS was typically related to occurrence of generalized seizure activity. Prognostic factors positively associated with short-term survival included having a history of preoperative seizures and development of focal seizures only. If affected dogs survived to discharge, survival for several years was possible, and the majority of neurologic signs manifested as part of the phenomenon of PANS appeared to resolve.

Prognostic factors for short-term survival of dogs that experience postattenuation seizures after surgical correction of single congenital extrahepatic portosystemic shunts: 93 cases (2005-2018).

OBJECTIVE: To identify prognostic factors for short-term survival of dogs that experience seizures within 7 days after surgical correction of single congenital extrahepatic portosystemic shunts (cEHPSS). STUDY DESIGN: Multi-institutional retrospective study. SAMPLE POPULATION: Ninety-three client-owned dogs. METHODS: Medical records at 14 veterinary institutions were reviewed to identify dogs that underwent surgical attenuation of a single cEHPSS from January 1, 2005 through February 28, 2018 and experienced postattenuation seizures (PAS) within 7 days postoperatively. Logistic regression analysis was performed to identify factors associated with 1-month survival. Factors investigated included participating institution, signalment, shunt morphology, concurrent/historical conditions, presence of preoperative neurologic signs, presence of preoperative seizures, aspects of preoperative medical management, surgical details including method and degree of shunt attenuation, type of PAS (focal only or generalized ± focal), drugs administered as part of the treatment of PAS, and development of complications during treatment of PAS. RESULTS: Thirty (32.3%) dogs survived to 30 days. Seventy-six (81.7%) dogs experienced generalized PAS. Factors positively associated with short-term survival included having a history of preoperative seizures (P = .004) and development of focal PAS only (P = .0003). Most nonsurvivors were humanely euthanized because of uncontrolled or recurrent seizures. CONCLUSION: Dogs that experienced PAS that had a history of preoperative seizures and those that experienced focal PAS only had significantly improved short-term survival. CLINICAL SIGNIFICANCE: The results of this study provide information that will help in the counseling of owners who seek treatment for PAS after surgical correction of cEHPSS. © 2020 The American College of Veterinary Surgeons.

Effect of prophylactic treatment with levetiracetam on the incidence of postattenuation seizures in dogs undergoing surgical management of single congenital extrahepatic portosystemic shunts.

OBJECTIVE: To report the incidence of postattenuation seizures (PAS) in dogs that underwent single congenital extrahepatic portosystemic shunt (cEHPSS) attenuation and to compare incidence of PAS in dogs that either did or did not receive prophylactic treatment with levetiracetam (LEV). STUDY DESIGN: Multi-institutional retrospective study. POPULATION: Nine hundred forty dogs. METHODS: Medical records were reviewed to identify dogs that underwent surgical attenuation of a single cEHPSS from January 2005 through July 2017 and developed PAS within 7 days postoperatively. Dogs were divided into 3 groups: no LEV (LEV-); LEV at ≥15 mg/kg every 8 hours for ≥24 hours preoperatively or a 60 mg/kg intravenous loading dose perioperatively, followed by ≥15 mg/kg every 8 hours postoperatively (LEV1); and LEV at <15 mg/kg every 8 hours, for <24 hours preoperatively, or continued at <15 mg/kg every 8 hours postoperatively (LEV2). RESULTS: Seventy-five (8.0%) dogs developed PAS. Incidence of PAS was 35 of 523 (6.7%), 21 of 188 (11.2%), and 19 of 228 (8.3%) in groups LEV-, LEV1, and LEV2, respectively. This difference was not statistically significant (P = .14). No differences between groups of dogs that seized with respect to investigated variables were identified. CONCLUSION: The overall incidence of PAS was low (8%). Prophylactic treatment with LEV according to the protocols that were investigated in our study was not associated with a reduced incidence of PAS. CLINICAL SIGNIFICANCE: Prophylactic treatment with LEV does not afford protection against development of PAS. Surgically treated dogs should continue to be monitored closely during the first 7 days postoperatively for seizures.

Canine Ovariohysterectomy: A Survey of Surgeon Concerns and Surgical Complications Encountered by Newly Graduated Veterinarians.

The objective of this study was to document newly qualified veterinarians' concerns and surgical complications encountered during canine ovariohysterectomy (cOVH) during the first year of general practice. A questionnaire investigating concerns about cOVH procedures was sent to all final-year veterinary students (group 1) enrolled at five UK universities. Participants were later asked to complete a similar questionnaire 6 months (group 2) and 12 months (group 3) after graduation, which involved grading their concern about different aspects of the cOVH procedure and reporting surgical complications encountered after completing three cOVHs. Responses were compared between different time points. There were 196 respondents in group 1, 55 in group 2, and 36 in group 3. Between groups 1 and 2, there was a statistically significant reduction in the respondents' levels of concern in every aspect of cOVH (p<.05). Between groups 2 and 3, there was no statistically significant change in respondents' levels of concern in any aspect of cOVH (p≥.21). There was a significant reduction in the number of complications encountered by veterinarians in group 3 (39/102, 38.2%) compared to those in group 2 (117/206, 56.8%) (p=.002). Employers should anticipate high levels of concern regarding all aspects of cOVHs in new graduates, and supervision during the first 6 months may be particularly useful.

Long-term outcome and quality of life of dogs that developed neurologic signs after surgical treatment of a congenital portosystemic shunt: 50 cases (2005-2020).

OBJECTIVE: To determine survival time and quality of life of dogs that developed postattenuation neurologic signs (PANS) after surgical treatment of a single congenital portosystemic shunt and survived at least 30 days and identify whether neurologic signs present at the time of discharge would resolve or reoccur. ANIMALS: 50 client-owned dogs. PROCEDURES: Medical records were retrospectively reviewed, and follow-up data relating to neurologic signs and seizure activity were obtained. Owners were asked to complete a questionnaire related to the presence of neurologic signs, including seizures, and their dog's quality of life. RESULTS: Thirty of the 50 (60%) dogs had postattenuation seizures with or without other nonseizure neurologic signs, and 20 (40%) had neurologic signs other than seizures. Neurologic signs had fully resolved by the time of discharge in 24 (48%) dogs. Signs resolved in 18 of the remaining 26 (69%) dogs that still had PANS other than seizures at the time of discharge. Seizures reoccurred in 15 of the 30 dogs that had postattenuation seizures. Twenty-seven of 33 (82%) owners graded their dog's long-term (> 30 days after surgery) quality-of-life as high. Forty-five (90%) dogs survived > 6 months. Most (29/43 [67%]) neurologic signs (other than seizures) present at the time of hospital discharge resolved. CLINICAL RELEVANCE: Findings highlighted that survival times of > 6 months and a high QOL can be achieved in most dogs with PANS that survive at least 30 days. Most neurologic signs other than seizures resolved within 1 month postoperatively. Half of the dogs with postattenuation seizures had a reoccurrence.

Investigation of the in vitro antimicrobial activity of triclosan-coated suture material on bacteria commonly isolated from wounds in dogs.

OBJECTIVE: To investigate in vitro effects of triclosan coating of suture materials on the growth of clinically relevant bacteria isolated from wounds in dogs. SAMPLE: 6 types of suture material and 10 isolates each of methicillin-susceptible Staphylococcus pseudintermedius, methicillin-resistant S pseudintermedius, Escherichia coli, and AmpC ß-lactamase and extended-spectrum ß-lactamase-producing E coli from clinical wound infections. PROCEDURES: Isolates were cultured on Mueller-Hinton agar with 3 types of triclosan-coated suture, uncoated counterparts of the same suture types, and positive and negative controls. Zones of inhibition (ZOIs) were measured after overnight incubation. Sustained antimicrobial activity assays were performed with susceptible isolates. The ZOI measurements and durations of sustained antimicrobial activity were compared among suture types and isolates by statistical methods. Suture surface characteristics and bacterial adherence were evaluated qualitatively with scanning electron microscopy. RESULTS: ZOIs were generated only by triclosan-coated materials; triclosan-coated suture had sustained antimicrobial activity (inhibition) for 3 to 29 days against all tested pathogens. The ZOIs around triclosan-coated suture were significantly greater for S pseudintermedius isolates than for E coli isolates. Bacterial adherence to uncoated polyglactin-910 was greatest, followed by triclosan-coated polyglactin-910, and then uncoated monofilament sutures, with least adherence to coated monofilament sutures. CONCLUSIONS AND CLINICAL RELEVANCE: Surface characteristics of suture materials may be as important or more important than triclosan coating for microbial inhibition; however, triclosan coating appeared to affect bacterial adherence for multifilament sutures. Triclosan-coated, particularly monofilament, sutures inhibited pathogens commonly isolated from wounds of dogs, including multidrug-resistant bacteria. Further studies are required to assess clinical efficacy of triclosan-coated suture materials in vivo.

Plasma cytokine concentrations in dogs with a congenital portosystemic shunt.

Congenital portosystemic shunts (cPSS) are a well-recognised vascular anomaly in dogs. Recent studies have shown an association between inflammation and hepatic encephalopathy (HE), which is a common clinical syndrome in dogs with a cPSS. Pro-inflammatory cytokines such as interleukin (IL)-6 and tumour necrosis factor (TNF)-α are frequently increased in the plasma of human patients with liver disease and have been implicated in the development of HE. In the current study, plasma concentrations of IL-2, IL-6, IL-8 and TNF-α were measured using a multiplex electrochemiluminescence immunoassay in 36 dogs with a cPSS and compared to 25 healthy dogs. There were no significant differences in plasma IL-2, IL-8 and TNF-α concentrations between the two groups; however, plasma concentrations of IL-6 were significantly higher in dogs with a cPSS compared to healthy dogs (P=0.02).

Nanocrystalline silver dressing and subatmospheric pressure therapy following neoadjuvant radiation therapy and surgical excision of a feline injection site sarcoma.

UNLABELLED: CLINICAL SUMMARY: This is the first clinical report of use of a combination of nanocrystalline silver and subatmospheric pressure therapy to treat a resistant wound infection, following tumour removal and radiation therapy, in a difficult-to-manage surgical site in a cat. PRACTICAL RELEVANCE: The therapy was well tolerated and the authors suggest it is a valid treatment protocol for management of non-healing or infected wounds in the cat.

Studies on the inhibition of feline EGFR in squamous cell carcinoma: enhancement of radiosensitivity and rescue of resistance to small molecule inhibitors.

This study investigated different methods of EGFR (Epithelial Growth Factor Receptor) targeting in feline squamous cell carcinoma with the ultimate aim of establishing a large animal model of human head and neck cancer. Both small molecule receptor tyrosine kinase inhibitor (TKI) and RNA interference (RNAi) techniques were employed to target the feline EGFR. We demonstrated that the human drug gefitinib caused a reduction in cell proliferation and migration in a feline cell line. However, we also document the development of resistance that was not associated with mutation in the kinase domain. RNAi caused a potent reduction in EGFR activity and was able to overcome acquired gefitinib resistance. In addition, RNAi targeting of EGFR, but not gefitinib, caused an additive effect on cell killing when combined with radiation. These results support the use of feline SCC as a model of head and neck cancer in man in the search for novel and effective treatments for both tumors.

Imaging diagnosis--congenital venous aneurysm of the left external jugular vein.

Primary congenital jugular vein aneurysms are rare with only one prior report in a canine patient. Herein, we describe an 18-week-old Flat Coated Retriever dog in which ultrasound was used to diagnose a primary congenital external jugular vein aneurysm with concurrent dilatation of the internal jugular vein. The aneurysm was successfully removed and the dog remains disease free 24 months postoperatively. Histopathologic analysis was used to validate the ultrasound-based diagnosis.

Patients lacking the major CNS myelin protein, proteolipid protein 1, develop length-dependent axonal degeneration in the absence of demyelination and inflammation.

Axonal degeneration contributes to clinical disability in the acquired demyelinating disease multiple sclerosis. Axonal degeneration occurs during acute attacks, associated with inflammation, and during the chronic progressive phase of the disease in which inflammation is not prominent. To explore the importance of interactions between oligodendrocytes and axons in the CNS, we analysed the brains of rodents and humans with a null mutation in the gene encoding the major CNS myelin protein, proteolipid protein (PLP1, previously PLP). Histological analyses of the CNS of Plp1 null mice and of autopsy material from patients with null PLP1 mutations were performed to evaluate axonal and myelin integrity. In vivo proton magnetic resonance spectroscopy (MRS) of PLP1 null patients was conducted to measure levels of N-acetyl aspartate (NAA), a marker of axonal integrity. Length-dependent axonal degeneration without demyelination was identified in the CNS of Plp1 null mice. Proton MRS of PLP1-deficient patients showed reduced NAA levels, consistent with axonal loss. Analysis of patients' brain tissue also demonstrated a length-dependent pattern of axonal loss without significant demyelination. Therefore, axonal degeneration occurs in humans as well as mice lacking the major myelin protein PLP1. This degeneration is length-dependent, similar to that found in the PNS of patients with the inherited demyelinating neuropathy, CMT1A, but is not associated with significant demyelination. Disruption of PLP1-mediated axonal--glial interactions thus probably causes this axonal degeneration. A similar mechanism may be responsible for axonal degeneration and clinical disability that occur in patients with multiple sclerosis.