Clinicopathologic evaluation of congenital idiopathic megaesophagus in a Gordon Setter puppy: a case report and development and application of peripherin immunohistochemistry for detection of ganglion cells.

We examined a case of congenital idiopathic megaesophagus (CIM) in a 5-wk-old female Gordon Setter puppy by means of contrast radiography, autopsy, histopathology, and immunohistochemistry. Clinical and radiologic findings included weight stagnation and marked generalized esophageal dilation with ventral displacement of the heart and lungs. These findings were confirmed at autopsy, and segments of the thoracic esophagus were sampled for histopathology. On histopathology, diffuse esophageal muscular atrophy, mucosal erosions, mononuclear inflammation, and a marked reduction in the number of myenteric plexus structures and number of ganglion cells were present (aganglionosis). The latter was determined immunohistochemically using an anti-peripherin antibody as the primary reagent, which provides a strong tool for the histologic confirmation of CIM. The histologic findings share some similarities to lesions associated with megaesophagus in Friesian foals, as well as esophageal achalasia and Hirschsprung disease in humans.

Suspected Fluoroquinolone-Induced Exacerbation of Myasthenia Gravis in Dogs.

Acquired myasthenia gravis (MG) in dogs can present with focal or generalized weakness and is diagnosed by the presence of circulating antibodies to the acetylcholine receptor. Megaesophagus is the most common focal form of MG. Although exacerbation of MG has been associated with the use of fluoroquinolones in humans, it has not been previously described in dogs. The medical records of 46 dogs diagnosed with MG based on acetylcholine receptor antibody testing from 1997 to 2021 were retrospectively evaluated to identify any dogs who demonstrated exacerbation of MG after the administration of a fluoroquinolone. Exacerbation of MG, from focal to generalized, occurred in a median of 4.5 days after initiation of fluoroquinolone therapy in six dogs. In addition, one dog with generalized MG and megaesophagus developed pyridostigmine resistance subsequent to fluoroquinolone therapy. Marked improvement in generalized weakness was reported 36 hr after discontinuation of fluoroquinolone therapy alone in one dog and in combination with pyridostigmine in two dogs. Fluoroquinolone therapy was never stopped in three dogs who were euthanized because of severe weakness and one dog who died of respiratory arrest.

Cricopharyngeal and thyropharyngeal myectomy for management of cricopharyngeal achalasia in a 6-month-old coton de Tulear dog.

A 6-week-old intact female coton de Tulear dog presented to a veterinary teaching hospital (VTH) internal medicine service for dysphagia that was persistent since birth. The patient was diagnosed with cricopharyngeal achalasia based on a fluoroscopic swallow study. To facilitate surgical intervention, a percutaneous endoscopic gastrostomy (PEG) tube was placed to bypass the upper esophageal sphincter and provide nutritional support until the dog was larger. At 6 mo of age, the dog underwent unilateral cricopharyngeal and thyropharyngeal myectomy. Marked improvement in dysphagia was noted immediately postoperatively. Improvement in dysphagia persisted in this dog, with continued marked improvement in clinical signs noted 1 y postoperatively. Key clinical message: Cricopharyngeal achalasia can be successfully managed with surgical intervention with a good long-term prognosis. Before surgical intervention, nutritional support is of critical importance. A combined procedure of cricopharyngeal and thyropharyngeal myectomy may be associated with outcomes superior to those of alternative procedures.

Myectomie cricopharyngée et thyropharyngée pour prise en charge de l'achalasie cricopharyngée chez un chien coton de Tuléar âgé de 6 mois. Une chienne coton de Tuléar femelle intacte âgée de 6 semaines a été présentée au service de médecine interne d'un CHU vétérinaire pour une dysphagie persistante depuis la naissance. Le patient a reçu un diagnostic d'achalasie cricopharyngée sur la base d'une étude fluoroscopique de la déglutition. Pour faciliter l'intervention chirurgicale, un tube de gastrostomie endoscopique percutanée (PEG) a été placé pour contourner le sphincter supérieur de l'oesophage et fournir un soutien nutritionnel jusqu'à ce que le chien soit plus gros. À l'âge de 6 mois, le chien a subi une myectomie cricopharyngée et thyropharyngée unilatérale. Une nette amélioration de la dysphagie a été notée immédiatement après l'opération. L'amélioration de la dysphagie a persisté chez ce chien, avec une amélioration continue et marquée des signes cliniques notée 1 an après l'opération.Message clinique clé :L'achalasie cricopharyngée peut être gérée avec succès par une intervention chirurgicale avec un bon pronostic à long terme. Avant l'intervention chirurgicale, le soutien nutritionnel est d'une importance cruciale. Une procédure combinée de myectomie cricopharyngée et thyropharyngée peut être associée à des résultats supérieurs à ceux des procédures alternatives.(Traduit par Dr Serge Messier).

GWAS using low-pass whole genome sequence reveals a novel locus in canine congenital idiopathic megaesophagus.

Congenital idiopathic megaesophagus (CIM) is a gastrointestinal disorder of dogs wherein the esophagus is dilated and swallowing activity is reduced, causing regurgitation of ingesta. Affected individuals experience weight loss and malnourishment and are at risk for aspiration pneumonia, intussusception, and euthanasia. Great Danes have among the highest incidences of CIM across dog breeds, suggesting a genetic predisposition. We generated low-pass sequencing data for 83 Great Danes and used variant calls to impute missing whole genome single-nucleotide variants (SNVs) for each individual based on haplotypes phased from 624 high-coverage dog genomes, including 21 Great Danes. We validated the utility of our imputed data set for genome-wide association studies (GWASs) by mapping loci known to underlie coat phenotypes with simple and complex inheritance patterns. We conducted a GWAS for CIM with 2,010,300 SNVs, identifying a novel locus on canine chromosome 1 (P-val = 2.76 × 10-10). Associated SNVs are intergenic or intronic and are found in two clusters across a 1.7-Mb region. Inspection of coding regions in high-coverage genomes from affected Great Danes did not reveal candidate causal variants, suggesting that regulatory variants underlie CIM. Further studies are necessary to assess the role of these non-coding variants.

Management and outcomes of 13 dogs treated with a modified Heller myotomy and Dor fundoplication for lower esophageal sphincter achalasia-like syndrome.

OBJECTIVE: To report the management and outcomes of dogs treated for lower esophageal sphincter achalasia-like syndrome (LES-AS) with modified Heller myotomy, Dor fundoplication, and with the use of a temporary gastrostomy tube. STUDY DESIGN: Retrospective. SAMPLE POPULATION: Thirteen client-owned dogs. METHODS: Medical records and a client survey were used to assess frequency of vomiting/regurgitation, quality of life (QoL), bodyweight, and feeding modifications at the following time points: prior to referral, postoperatively from discharge to first recheck (4-6 weeks), and from first recheck to survey (48 months). Postoperative and gastrostomy tube complications were surveyed and recorded. Pretreatment and 4-6 weeks postoperative videofluoroscopic swallow studies (VFSS) were compared. Two-sided t-tests were used to compare outcomes between survey time points. RESULTS: Postoperative VFSS scores (available in 9 dogs) improved over preoperative scores in 6 dogs, and 12/13 dogs survived to discharge. One dog was euthanized 3 days postoperatively due to aspiration pneumonia. Postoperative gastrostomy tube complications occurred in half of the dogs that survived to discharge. According to the owners, scores assigned to vomiting/regurgitation improved by 180% (P = .004), QoL by 100% (P = .004), and bodyweight by 63% (P = .035). CONCLUSION: Modified Heller myotomy with Dor fundoplication and the use of a temporary gastrostomy tube improved clinical signs and owners' perceived quality of life in half of the dogs treated for LES-AS in our clinical setting. Oral sildenafil therapy discontinued postoperatively suggests that surgery was equally efficacious. CLINICAL SIGNIFICANCE: Modified Heller myotomy with Dor fundoplication and temporary gastrostomy tube is a treatment option with potentially sustained benefits for dogs that have LES-AS.

Use of a videofluoroscopic feeding evaluation to guide management of dogs with congenital idiopathic megaoesophagus.

BACKGROUND: Evidence-based guidelines for determining dietary management in dogs with megaoesophagus are lacking. OBJECTIVES: This study looked to compare oesophageal clearance times (ECT) of liquid and two food consistencies using a contrast videofluoroscopy feeding evaluation, and to assess if recommendations made based on findings could improve regurgitation and quality of life in dogs with congenital megaoesophagus. METHODS: Twenty-one dogs with congenital megaoesophagus and nine healthy dogs received liquid, slurry, and meatball diets containing barium while in an upright position. Follow-up was performed to determine response to recommendations. RESULTS: Healthy dogs had significantly shorter median ECT for all consistencies (p < 0.001). In the megaoesophagus group, ECT varied by consistency and individual. The number of dogs in the megaoesophagus group with complete clearance was four (median ECT 10 min) for liquid, five (median ECT 5 min) for slurry, and two (median ECT 5 and 30 min, respectively) for meatballs. Partial clearance was seen in 11 dogs (median clearance 25%) with liquid, seven with slurry (median clearance 50%), and five with meatballs (median clearance 60%). Recommendations included altering current medications (13/21 dogs), diet consistency (6/21), time upright (12/21), water delivery (21/21), and adding activity (7/21). Regurgitation episodes/week decreased significantly from 5.5 to 2.5 (p < 0.001) at follow-up 3-5 weeks post-evaluation, with 95% of owners reporting improvement in quality of life. Seventy percent were alive 46-777 days after last recheck. Three dogs died from megaoesophagus associated complications (median survival 461 days after diagnosis). CONCLUSIONS: The findings of this study suggest that a videofluoroscopic feeding evaluation may help guide management of dogs with congenital megaoesophagus.

Congenital idiopathic megaesophagus in the German shepherd dog is a sex-differentiated trait and is associated with an intronic variable number tandem repeat in Melanin-Concentrating Hormone Receptor 2.

Congenital idiopathic megaesophagus (CIM) is a gastrointestinal (GI) motility disorder of dogs in which reduced peristaltic activity and dilation of the esophagus prevent the normal transport of food into the stomach. Affected puppies regurgitate meals and water, fail to thrive, and experience complications such as aspiration pneumonia that may necessitate euthanasia. The German shepherd dog (GSD) has the highest disease incidence, indicative of a genetic predisposition. Here, we discover that male GSDs are twice as likely to be affected as females and show that the sex bias is independent of body size. We propose that female endogenous factors (e.g., estrogen) are protective via their role in promoting relaxation of the sphincter between the esophagus and stomach, facilitating food passage. A genome-wide association study for CIM revealed an association on canine chromosome 12 (P-val = 3.12x10-13), with the lead SNPs located upstream or within Melanin-Concentrating Hormone Receptor 2 (MCHR2), a compelling positional candidate gene having a role in appetite, weight, and GI motility. Within the first intron of MCHR2, we identified a 33 bp variable number tandem repeat (VNTR) containing a consensus binding sequence for the T-box family of transcription factors. Across dogs and wolves, the major allele includes two copies of the repeat, whereas the predominant alleles in GSDs have one or three copies. The single-copy allele is strongly associated with CIM (P-val = 1.32x10-17), with homozygosity for this allele posing the most significant risk. Our findings suggest that the number of T-box protein binding motifs may correlate with MCHR2 expression and that an imbalance of melanin-concentrating hormone plays a role in CIM. We describe herein the first genetic factors identified in CIM: sex and a major locus on chromosome 12, which together predict disease state in the GSD with greater than 75% accuracy.

A randomized crossover study of compounded liquid sildenafil for treatment of generalized megaesophagus in dogs.

OBJECTIVE: To determine whether delivery of compounded liquid sildenafil directly to the stomach of dogs with megaesophagus (ME) would affect esophageal clearance, regurgitation frequency, body weight, or quality of life. ANIMALS: 10 client-owned otherwise healthy dogs with stable ME. PROCEDURES: A randomized crossover study was performed. Dogs received either sildenafil (1 mg/kg, PO, q 12 h) or a placebo for 14 days, followed by a 7-day washout period, then the opposite treatment for 14 days. Esophageal clearance time was assessed by means of videofluoroscopy prior to treatment and on day 1 of each treatment period. Owners maintained logs of regurgitation episodes and quality of life. RESULTS: Compounded liquid sildenafil moved into the stomach during 21 of 30 (70%) videofluoroscopy sessions. Sildenafil resulted in a significant reduction in the number of regurgitation episodes (median, 3.5 episodes/wk; range, 0 to 14.5 episodes/wk), compared with baseline (median, 6.5 episodes/wk; range, 1.5 to 19.5 episodes/wk) and the placebo (median, 4 episodes/wk; range, 0 to 28 episodes/wk), and a significant increase in body weight (median, 22.05 kg; range, 6 to 26.3 kg), compared with baseline (median, 21.55 kg; range, 5.1 to 26.2 kg) and the placebo (median, 22.9 kg; range, 5.8 to 25.9 kg). There were no differences in esophageal clearance times or quality-of life-scores between sildenafil and placebo. CLINICAL RELEVANCE: Although significant differences with placebo administration were identified, clinically relevant improvements were not seen with the use of compounded liquid sildenafil in dogs with ME.

Postoperative improvement of megaesophagus and esophageal motility in a 19-day-old puppy with gastroesophageal intussusception.

Canine gastroesophageal intussusception (GEI) is a rare and life-threatening condition that requires prompt diagnosis and treatment. A 19-day-old Siberian Husky with a 4-day history of regurgitation was diagnosed with GEI based on the findings of computed tomography (CT) performed without anesthesia. Endoscopic reduction of intussusception was impossible; thus, surgical reduction by traction of the duodenum was performed. CT revealed improvement of megaesophagus 82 days postoperatively. Eleven months postoperatively, fluoroscopy showed recovery to nearly normal esophageal motility. Two years postoperatively, no clinical signs were reported. CT is useful to diagnose GEI in neonate puppies with poor abdominal fat and to assess the gastric edema and the anatomical association of stomach with other organs. Fluoroscopy is helpful for evaluating postoperative esophageal motility.

A comparative analysis of two unrelated outbreaks in Latvia and Australia of acquired idiopathic megaesophagus in dogs fed two brands of commercial dry dog foods: 398 cases (2014-2018).

CASE DESCRIPTION: In Latvia in 2014, acquired idiopathic megaesophagus (AIME) was observed in increased numbers of dogs that consumed varieties of 1 brand of dog food. Within 2 years, 253 dogs were affected. In Australia in November 2017, 6 working dogs that consumed 1 diet of another brand of dog food developed AIME. In total, 145 Australian dogs were affected. CLINICAL FINDINGS: AIME was diagnosed predominantly in large-breed male dogs (> 25 kg [55 lb]). Regurgitation, weight loss, and occasionally signs consistent with aspiration pneumonia (coughing, dyspnea, or fever) were noted. Most Latvian dogs had mild to severe peripheral polyneuropathies as evidenced by laryngeal paralysis, dysphonia, weakness, and histopathologic findings consistent with distal axonopathy. In Australian dogs, peripheral polyneuropathies were not identified, and histopathologic findings suggested that the innervation of the esophagus and pharynx was disrupted locally, although limited samples were available. TREATMENT AND OUTCOME: Investigations in both countries included clinical, epidemiological, neuropathologic, and case-control studies. Strong associations between the dog foods and the presence of AIME were confirmed; however, toxicological analyses did not identify a root cause. In Latvia, the implicated dietary ingredients and formulations were unknown, whereas in Australia, extensive investigations were conducted into the food, its ingredients, the supply chain, and the manufacturing facilities, but a cause was not identified. CLINICAL RELEVANCE: A panel of international multidisciplinary experts concluded that the cause of AIME in both outbreaks was likely multifactorial, with the possibility of individualized sensitivities. Without a sentinel group, the outbreak in Australia may not have been recognized for months to years, as happened in Latvia. A better surveillance system for early identification of pet illnesses, including those associated with pet foods, is needed.

Aberrant right subclavian artery in a dog - case report / [Ectopia de artéria subclávia direita em cão - relato de caso]

The brachiocephalic trunk and the left subclavian artery originate from the aortic arch, and both supply blood to the head, neck, and thoracic limbs. Anatomical variations, such as an aberrant right subclavian artery, are congenital conditions rarely observed in dogs, Thus, the objective of the present report was to describe a case of aberrant right subclavian artery in a 9-year-old Dalmatian. However, this anomaly was a finding in which the patient was asymptomatic during its 9 years of life and only at this age did he exhibit signs including sialorrhea, vomiting, hyporexia, and noisy deglutition. Blood count, biochemical profile, and thoracic radiography led to a diagnosis of megaesophagus and aspiration pneumonia. Despite the recommended treatment, the patient did not respond well; as such, the owner elected to euthanize the animal. On necropsy, the right subclavian artery originated directly from the aortic arch, followed a route from left to right dorsally to the esophagus, and then formed an impression of the vascular path over the muscular wall of the esophagus. The esophagus, in turn, exhibited a flaccid wall and dilation in the caudal portion to the vascular path made by the ectopic position of the right subclavian artery.(AU)

O tronco braquiocefálico e a artéria subclávia esquerda emergem do arco aórtico e são responsáveis por fazerem o suprimento sanguíneo para cabeça, pescoço e membros torácicos. Variações anatômicas, como a ectopia da artéria subclávia direita, são alterações congênitas raramente encontradas em cães, cujas alterações do sistema digestivo acontecem em pacientes recém-desmamados e não em adultos. Assim, o objetivo deste relato é descrever um caso de ectopia da artéria subclávia direita em uma cadela, Dálmata, de nove anos de idade. No entanto, essa anomalia foi um achado do qual o paciente foi assintomático durante os nove anos de vida e somente com essa idade apresentou sinais como sialorreia, vômito, hiporexia e deglutição ruidosa. O hemograma e os perfis bioquímicos, associados à radiografia torácica, levaram a um diagnóstico de megaesôfago e pneumonia aspirativa. Mesmo seguindo o tratamento recomendado, houve piora clínica do quadro e o animal foi submetido à eutanásia. À macroscopia, a artéria subclávia direita originava-se direto do arco aórtico, fazia um percurso da esquerda para a direita dorsalmente ao esôfago e, então, formava uma impressão do trajeto vascular sobre a parede muscular do esôfago. O esôfago, por sua vez, apresentava parede flácida e dilatação na porção caudal ao trajeto vascular feito pela posição ectópica da artéria subclávia direita.(AU)

Transient Megaesophagus Following Coral Snake Envenomation in Three Dogs (2013-2018).

A 12 yr old dachshund, a 7 yr old English springer spaniel, and a 1.5 yr old French bulldog presented following envenomation by a coral snake. Each patient displayed evidence of varying degrees of lower motor neuron dysfunction, but all three developed transient megaesophagus. Two patients developed secondary aspiration pneumonia, with one requiring mechanical ventilation, which the owners declined, resulting in euthanasia. The third developed hypoventilation without aspiration pneumonia, was mechanically ventilated, and was successfully weaned. In the two surviving patients, the megaesophagus resolved by time of discharge. Coral snake envenomation is an uncommon occurrence, and these are the first documented cases of transient megaesophagus secondary to a North American species.

Polyneuropathy in Young Siberian Huskies Caused by Degenerative and Inflammatory Diseases.

Polyneuropathy is defined as the simultaneous dysfunction of several peripheral nerves. In dogs, a number of breeds are predisposed to a variety of immune-mediated and/or degenerative inherited forms of polyneuropathy, with laryngeal paralysis and/or megaesophagus as important clinical features of many of these conditions. This case series describes degenerative and inflammatory polyneuropathies in 7 young Siberian huskies that were categorized based on clinicopathological characteristics as follows: (1) slowly progressive laryngeal paralysis and megaesophagus caused by primary axonal degeneration with large fiber loss (n = 2); (2) slowly progressive polyneuropathy without megaesophagus or laryngeal paralysis caused by primary axonal degeneration with large fiber loss (n = 2); (3) acute inflammatory demyelinating neuropathy causing sensory, motor and autonomic nerve deficits (n = 2); and (4) ganglioradiculitis (sensory neuronopathy; n = 1). Based on the predominantly young age at onset, slow progression, relatedness of affected dogs, and clinical and pathological similarities with inherited neuropathies reported in other dog breeds, a hereditary basis for the degenerative polyneuropathies in Siberian huskies is suspected. However, 5 different mutations in 3 genes known to cause polyneuropathy in other dog breeds (NDRG1, ARHGEF10, or RAB3GAP1) were not detected in the affected Siberian huskies suggesting that more genetic variants remain to be identified. This study highlights the varied underlying lesions of polyneuropathies in young Siberian huskies.

A case-control study to identify risk factors for adult-onset idiopathic megaoesophagus in Australian dogs, 2017-2018.

BACKGROUND: Epidemiological investigations were carried out following detection of an outbreak of megaoesophagus in Victorian Police working dogs in early 2018 and an increase in the number of canine megaoesophagus cases reported by companion animal veterinarians in Eastern Australia starting in late 2017. VetCompass Australia data were used to quantify the incidence of canine megaoesophagus for the period January 2012 to February 2018 and a matched case-control study carried out to identify individual animal risk factors for canine megaoesophagus in 2017-2018. RESULTS: There was a 7-fold increase in the incidence rate of canine megaoesophagus from 2014 (0.11 [95% CI 0.02 to 0.58] cases per 100,000 dogs per day) to 2018 (0.82 [95% CI 0.19 to 4.2] cases per 100,000 dogs per day). Since 2013, the incidence of megaoesophagus in Australia has shown a seasonal pattern, with greater numbers of cases diagnosed during the warmer months of the year. In the case-control study, use of Mars Petcare Advance Dermocare as a source of food was 325 (95% CI 64 to 1644) times greater for cases, compared with controls. CONCLUSIONS: Our analyses provide evidence that the feeding of Advance Dermocare was responsible for the majority of cases in the outbreak of megaoesophagus in Eastern Australia in 2017-2018. The increase in the incidence rate of megaoesophagus in Australia since 2014-2015 warrants further investigation.

Characteristics and long-term outcomes of dogs with gastroesophageal intussusception.

OBJECTIVE: To determine long-term outcomes and factors associated with those outcomes in dogs with gastroesophageal intussusception (GEI). ANIMALS: 36 dogs with GEI evaluated at 16 veterinary hospitals from January 2000 through January 2018. PROCEDURES: Medical records of included dogs were reviewed to collect information regarding signalment, clinical signs, physical examination findings, blood work and diagnostic imaging results, surgical findings, and outcome. Factors were evaluated for associations with various outcomes. RESULTS: Median age of dogs with GEI was 13.2 months, and males (72% [26/36]) and German Shepherd Dogs (33% [12/36]) were most common. Vomiting (67% [24/36]) and regurgitation (33% [12/36]) were the most common clinical signs. Ten of 36 (28%) dogs were euthanized without treatment, and 26 (72%) underwent treatment (25 surgically and 1 endoscopically). Twenty-three of the 26 (88%) treated dogs survived to discharge; median survival time was 995 days. At last follow-up, 15 of the 23 (65%) surviving dogs remained alive and 8 (35%) had died for reasons related to persistent regurgitation (n = 6) or reasons unrelated to GEI (2). Of the 10 dogs for which owners were contacted, 7 had persistent regurgitation, the severity of which was reduced through managed feedings. Dogs with acute (≤ 7 days) clinical signs or a previous diagnosis of megaesophagus were more likely to have persistent regurgitation than were dogs without these factors. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment should be considered for dogs with GEI given the high rate of survival to discharge and median survival time. Although persistent regurgitation was common after treatment, a satisfactory outcome was possible with medical management, including managed feedings and medications.

Megaesophagus Is a Major Pathological Condition in Rats With a Large Deletion in the Rbm20 Gene.

A spontaneously arising, loss-of-function mutation in the RNA binding motif protein 20 (Rbm20) gene, which encodes a nuclear splicing protein, was previously identified as the underlying reason for expression of an abnormally large TITIN (TTN) protein in a rat model of cardiomyopathy. An outbreak of Pseudomonas aeruginosa led to submission of rats with dyspnea, sneezing, lethargy, nasal discharge, and/or unexpected death for diagnostic evaluation. Necropsy revealed underlying megaesophagus in Rbm20-/- rats. Further phenotyping of this rat strain and determination of the size of esophageal TTN was undertaken. The Rbm20-defective rats developed megaesophagus at an early age (26 weeks) with high frequency (13/32, 41%). They also often exhibited secondary rhinitis (9/32, 28%), aspiration pneumonia (8/32, 25%), and otitis media/interna (6/32, 19%). In addition, these rats had a high prevalence of hydronephrosis (13/32, 41%). RBM20 is involved in splicing multiple RNA transcripts, one of which is the muscle-specific protein TTN. Rbm20 mutations are a significant cause of dilated cardiomyopathy in humans. In Rbm20-defective rats, TTN size was significantly increased in the skeletal muscle of the esophagus. Megaesophagus in this rat strain (maintained on a mixed genetic background) is hypothesized to result from altered TTN stretch signaling in esophageal skeletal muscle. This study describes a novel mechanism for the development of megaesophagus, which may be useful for understanding the pathogenesis of megaesophagus in humans and offers insights into potential myogenic causes of this condition. This is the first report of megaesophagus and other noncardiac pathogenic changes associated with mutation of Rbm20 in any species.

Canine Nonstructural Megaesophagus as a Clinical Sign of Potential Neurological Disease: 99 Cases.

Knowledge regarding the etiology and prognosis for canine megaesophagus (ME) is currently limited to small case series that may now be out of date in light of recent advances in the understanding of neurological syndromes and the availability of advanced diagnostic testing. Ninety-nine dogs diagnosed with nonstructural ME were included. Congenital idiopathic ME was present in 10 cases, with complete resolution of clinical signs in a single case. Eighty-nine cases were considered acquired, with most cases being either idiopathic (42.7%) or associated with myasthenia gravis (38.2%). Idiopathic cases represented a smaller percentage of acquired ME than previously reported. Death or euthanasia directly related to ME occurred in almost 50% of acquired cases, whereas clinical signs persisted in ∼20% of cases and resolved in 30% of cases. A diagnosis of an underlying etiology, in particular myasthenia gravis, was associated with a better outcome in acquired ME. ME continues to be a challenging condition to manage, with a guarded-to-poor prognosis, particularly when an underlying etiology is not identified. Thorough diagnostic testing for an underlying neurological disorder is important in cases with ME as this may allow institution of appropriate treatment and the potential for a better prognosis.

Distal esophageal sphincter achalasia in a Labrador retriever dog with polypoid gastric mucosal hyperplasia and pyloric stenosis.

An 11-year-old, neutered female, Labrador retriever dog was presented with a history of intractable vomiting, regurgitation, and coughing. Computed tomography (CT) imaging identified marked hypertrophy of the distal esophagus with a suspicion of distal esophageal achalasia, based on the observation of a "bird beak" appearance. This was later confirmed on a fluoroscopic swallow study. Marked hypertrophy of the gastric pylorus was also identified on CT imaging, and polypoid gastric mucosal hyperplasia was diagnosed based on the gross endoscopic appearance combined with gastric histopathology. Secondary aspiration pneumonia was diagnosed based on the results of CT imaging, bronchoscopy and bronchoalveolar lavage fluid analysis. Medical therapy alone failed to elicit any significant improvement, but clinical resolution was achieved following surgical intervention comprising Ventral Heller myotomy, Dor's fundoplication, and pyloroplasty.

Achalasie du sphincter oesophagien distal chez un chien de race Labrador avec hyperplasie polypoïde de la muqueuse gastrique et sténose du pylore. Une femelle Labrador stérilisée âgée de 11 ans fut présentée avec une histoire de vomissements intraitables, de régurgitation et de toux. Un examen par tomodensitométrie (CT) identifia une hypertrophie marquée de l'oesophage distal avec un doute d'achalasie oesophagienne distale, sur la base de l'observation d'une apparence en « bec d'oiseau ¼. Ceci fut ultérieurement confirmé par examen fluoroscopique. Une hypertrophie marquée du pylore gastrique fut également identifiée lors de l'examen par CT, et une hyperplasie polypoïde de la muqueuse gastrique fut diagnostiquée sur la base de l'apparence macroscopique lors de l'endoscopie combinée avec l'examen histopathologique de la muqueuse gastrique. Une pneumonie par aspiration secondaire fut diagnostiquée basée sur les résultats du CT, de la bronchoscopie et de l'analyse du liquide de lavage broncho-alvéolaire. Une thérapie médicale seule ne parvint pas à éliciter une amélioration significative, mais une résolution clinique fut obtenue à la suite d'une intervention chirurgicale comprenant une myotomie ventrale de Heller, une fundoplicature de Dor, et une pyloroplastie.(Traduit par Dr Serge Messier).

Videofluoroscopic swallow study features of lower esophageal sphincter achalasia-like syndrome in dogs.

BACKGROUND: Megaesophagus (ME) carries a poor long-term prognosis in dogs. In people, lower esophageal sphincter (LES) disorders causing functional obstruction are rare causes of ME that may respond to targeted treatment. Functional LES disorders are reported rarely in dogs because of challenges in diagnostic methodologies. HYPOTHESIS/OBJECTIVES: To identify dogs with videofluoroscopic swallow study (VFSS) features of LES achalasia-like syndrome (LES-AS). We hypothesized that dogs with LES-AS could be distinguished from normal dogs using standardized VFSS criteria. ANIMALS: Dogs with LES-AS by VFSS (n = 19), healthy normal dogs (n = 20). METHODS: Retrospective study. One-hundred thirty dogs presented to the University of Missouri Veterinary Health Center (MU-VHC) between April 2015 and December 2017 for a free-feeding VFSS; 20 healthy dogs were included as controls. Swallow studies were evaluated for failure of the LES to relax during pharyngeal swallow (LES-AS). Affected dogs subsequently were evaluated using standardized criteria to identify metrics important for identifying and characterizing dogs with LES-AS. RESULTS: Nineteen dogs with LES-AS were identified out of 130 VFSS. Megaesophagus was present in 14 of 19 (73.7%) dogs with LES-AS. A baseline esophageal fluid-line and "bird beak" were present in 68.4% (95% confidence interval [CI], 47.5%-89.3%) and 63.2% (95% CI, 41.5%-84.8%) of affected dogs, respectively. The esophagus was graded as acontractile (8/19), hypomotile (8/19), or hypermotile (3/19). CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with LES-AS may successfully be identified by VFSS using a free-feeding protocol. These data are of critical clinical importance because a subpopulation of dogs with functional LES obstruction may be candidates for targeted intervention.

Technique for Evaluation of Gravity-Assisted Esophageal Transit Characteristics in Dogs with Megaesophagus.

Movement of food material in the esophagus during upright feeding in dogs with megaesophagus (ME) is poorly characterized. A standardized contrast videofluoroscopy technique was used to evaluate esophageal transit characteristics in dogs with ME while in an upright position. Twelve dogs with ME (congenital, acquired idiopathic, or secondary to myasthenia gravis) were placed in an upright position using Bailey chairs and given liquid barium, canned food meatballs, and their normal diet consistency if different than meatballs. Passage of ingesta was videofluoroscopically evaluated by direct observation and change in ingesta area as determined by manual tracing or barium column product calculations. Significant individual variation was seen. Complete esophageal clearance of liquid was seen in four dogs, and complete clearance of meatballs in three dogs, with a median time of 5 min for both. Two of seven dogs fed a slurry diet had complete clearance by 10 min. No significant difference was found between area calculated via tracing or barium column product. Based on imaging results, alterations in food consistency, duration upright, or medication were recommended for nine dogs. In dogs with ME accustomed to a Bailey chair, contrast videofluoroscopy was technically straightforward and allowed for more specific physician-guided management recommendations.