The domestic dog may be the most morphologically diverse terrestrial mammalian species known to man; pedigree dogs are artificially selected for extreme aesthetics dictated by formal Breed Standards, and breed-related disorders linked to conformation are ubiquitous and diverse. Brachycephaly–foreshortening of the facial skeleton–is a discrete mutation that has been selected for in many popular dog breeds e.g. the Bulldog, Pug, and French Bulldog. A chronic, debilitating respiratory syndrome, whereby soft tissue blocks the airways, predominantly affects dogs with this conformation, and thus is labelled Brachycephalic Obstructive Airway Syndrome (BOAS). Despite the name of the syndrome, scientific evidence quantitatively linking brachycephaly with BOAS is lacking, but it could aid efforts to select for healthier conformations. Here we show, in (1) an exploratory study of 700 dogs of diverse breeds and conformations, and (2) a confirmatory study of 154 brachycephalic dogs, that BOAS risk increases sharply in a non-linear manner as relative muzzle length shortens. BOAS only occurred in dogs whose muzzles comprised less than half their cranial lengths. Thicker neck girths also increased BOAS risk in both populations: a risk factor for human sleep apnoea and not previously realised in dogs; and obesity was found to further increase BOAS risk. This study provides evidence that breeding for brachycephaly leads to an increased risk of BOAS in dogs, with risk increasing as the morphology becomes more exaggerated. As such, dog breeders and buyers should be aware of this risk when selecting dogs, and breeding organisations should actively discourage exaggeration of this high-risk conformation in breed standards and the show ring.

Surgical attenuation of a single CPSS should not be excessively delayed, and surgeons should stabilize the clinical signs of HE before surgery to prevent postoperative PANS and seizures.

Objective To determine the incidence, outcome, and risk factors for postattenuation neurological signs (PANS) in cats treated for single congenital portosystemic shunts (CPSS). Study design Retrospective cohort study. Animals Cats (n = 50) with a single CPSS. Methods Medical records of cats treated by surgical attenuation of a single CPSS between 2003 and 2017 were reviewed for signalment, surgical technique, preoperative management and postoperative clinical outcomes. Binary logistic regression was performed to investigate risk factors for occurrence of PANS and seizures. Results Congenital portosystemic shunts in 50 cats included 40 extrahepatic and 10 intrahepatic shunts. Postattenuation neurological signs were recorded in 31 (62%) cats and graded as 1 in 10 cats, 2 in nine cats, and 3 in 12 cats. Postattenuation neurological signs included seizures in 11 cats. Five of 31 cats with PANS did not survive to discharge. No association was detected between PANS or seizures and the type of CPSS (intrahepatic or extrahepatic), degree of attenuation, age, or the use of perioperative levetiracetam or hepatic encephalopathy immediately preoperatively. Osmolality at a median 24 hours postoperatively was lower in cats with PANS (P < .049, Wald 3.867, odds ratio [Exp(B)] 0.855, CI 0.732‐0.999). Conclusion Postattenuation neurological signs are common complications in cats treated for CPSS. Preoperative levetiracetam did not prevent the occurrence of PANS or seizures. The only risk factor for PANS detected was lower postoperative Osmolality in cats with PANS at 24 hours. Clinical significance Postattenuation neurological signs including seizures occur frequently in cats undergoing surgical attenuation of a CPSS. Preoperative levetiracetam did not protect against the development of PANS.

Brachycephalic (short-muzzled) dogs are increasingly popular pets worldwide, with marked increases in registrations of breeds such as the Pug and French Bulldog over the past decade in the UK. Despite their popularity, many brachycephalic breeds are affected by an early-onset, lifelong respiratory disorder, brachycephalic obstructive airway syndrome (BOAS). This disorder arises due to a mismatch in the proportions of the skull and the soft tissues held within the nose and pharynx, resulting in obstruction of the airway during respiration. Increased airway resistance encourages secondary changes such as eversion of the laryngeal saccules and collapse of the larynx. Clinical signs of BOAS are often early onset and chronic, including dyspnea, exercise intolerance, heat intolerance, and abnormal and increased respiratory noise. Episodes of severe dyspnea can also occur, leading to cyanosis, syncope, and death. BOAS may have a severe impact upon the welfare of affected dogs, compromising their ability to exercise, play, eat, and sleep. Although a well-described condition, with surgical treatments for the palliation of this disorder published since the 1920s, many dogs still experience airway restrictions postsurgically and a compromised quality of life. In addition, the prevalence of this disorder does not appear to have substantially reduced in this time, and may have increased. Ultimately, strategies to improve the breeding of these dogs to prevent BOAS are required to improve brachycephalic health and welfare. Recent studies have revealed conformational risk factors associated with BOAS, such as short muzzles and thick necks, which should be discouraged to avoid perpetuating this serious disorder. Positive changes to brachycephalic health may be impeded by a perception of BOAS being “normal for the breed”. This perception must be avoided by owners, breeders, and vets alike to prevent undertreatment of individuals and the perpetuation of this serious disorder to future generations of dogs.

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).Preliminary results of this study were presented at the Association

BackgroundGall bladder mucoceles (GBM) are a leading cause of biliary disease in dogs with several breeds, including the Shetland Sheepdog, American Cocker Spaniel, Chihuahua, Pomeranian, and Miniature Schnauzer apparently predisposed.ObjectiveTo determine risk factors, clinical features, and response to treatment of GBM in Border terriers (BT).AnimalsMedical records of 99 dogs (including 51 BT) with an ultrasonographic (±histopathologic) diagnosis of GBM from three referral centers in the United Kingdom were collected. A control group of 87 similar‐aged BT with no ultrasonographic evidence of gall bladder disease was selected for comparison.MethodRetrospective case‐control study. Odds ratios were calculated to establish breed predisposition. Signalment, presence of endocrine disease, clinicopathologic results, and outcome were compared between the BT, other breeds, and control BTs.ResultsThe odds of identifying a GBM in a BT in this hospital population was 85 times that of all other breeds (95% confidence interval 56.9‐126.8). BT had similar clinical signs and clinicopathologic changes to other breeds with GBM. There was no evidence that endocrinopathies were associated with GBM in BT.Clinical SignificanceA robust breed predisposition to GBM is established for the BT.

Despite several retrospective studies of cats with CPSSs, the evidence base for management of the condition remains limited.

Hepatic encephalopathy (HE) is an important cause of morbidity and mortality in patients with liver disease. The pathogenesis of he is incompletely understood although ammonia and inflammatory cytokines have been implicated as key mediators. To facilitate further mechanistic understanding of the pathogenesis of HE, a large number of animal models have been developed which often involve the surgical creation of an anastomosis between the hepatic portal vein and the caudal vena cava. One of the most common congenital abnormalities in dogs is a congenital portosystemic shunt (cpss), which closely mimics these surgical experimental models of HE. Dogs with a cPSS often have clinical signs which mimic clinical signs observed in humans with HE. Our hypothesis is that the pathogenesis of HE in dogs with a cPSS is similar to humans with HE. The aim of the study was to measure a range of clinical, haematological and biochemical parameters, which have been linked to the development of HE in humans, in dogs with a cPSS and a known HE grade. One hundred and twenty dogs with a cPSS were included in the study and multiple regression analysis of clinical, haematological and biochemical variables revealed that plasma ammonia concentrations and systemic inflammatory response syndrome scores predicted the presence of HE. Our findings further support the notion that the pathogenesis of canine and human HE share many similarities and indicate that dogs with cPSS may be an informative spontaneous model of human HE. Further investigations on dogs with cPSS may allow studies on HE to be undertaken without creating surgical models of HE thereby allowing the number of large animals used in animal experimentation to be reduced.