Prospective Controlled Study of Gastroesophageal Reflux in Dogs with Naturally Occurring Laryngeal Paralysis

Prevalence of gastroesophageal reflux in dogs undergoing MRI for a thoracolumbar vertebral column pathology

OBJECTIVES

The aims of the study were to investigate the prevalence and extent of gastroesophageal reflux, and the prevalence of regurgitation in dogs undergoing thoracolumbar spine magnetic resonance imaging, and to explore possible associations of reflux and regurgitation with signalment (breed, age, sex, neuter status), bodyweight, body condition score and drugs used in the anaesthetic protocol.

MATERIALS AND METHODS

The thoracic part of the oesophagus was retrospectively assessed for presence and quantification of fluid on two T2 weighted sequences. Patient breed, age, sex, neuter status, weight and body condition score were recorded. Anaesthetic records were reviewed for the presence of regurgitation and detailed anaesthetic protocols.

RESULTS

Fifty percent [95% confidence interval (44.99, 56.81)] of included dogs had evidence of gastroesophageal reflux. Reflux was not associated with the individual breed, age, sex, neuter status or body weight. Brachycephalic dogs did not demonstrate significantly higher rates of reflux compared to non-brachycephalic dogs. A larger volume of reflux was associated with a higher chance of regurgitation.

CLINICAL SIGNIFICANCE

Gastroesophageal reflux is a common finding in dogs undergoing thoracolumbar spine magnetic resonance imaging. Dogs which regurgitated had higher volumes of reflux. Early detection and quantification of the volume of reflux is helpful as it may allow the anaesthetist to take measures which may reduce the risk of associated complications.

Strongly acidic gastroesophageal reflux and esophageal lumen pH before and after esophageal lavage with water or two bicarbonate concentrations in anesthetized dogs

OBJECTIVE

To increase acidic esophageal lumen pH in dogs that developed gastroesophageal reflux (GER) during anesthesia. We compared water and 2 different bicarbonate concentrations.

ANIMALS

112 healthy, nonbrachycephalic dogs presented for ovariectomy.

PROCEDURES

Following standard anesthesia and surgery protocols for ovariectomy in all dogs, esophageal lumen impedance and pH were monitored using a dedicated probe. Esophageal impedance indicates the presence of GER whereas pH indicates the acidity level. Dogs with strongly acidic GER and an esophageal lumen pH value < 4.0 were included in the study, and lavage was performed with either tap water, bicarbonate 1%, or bicarbonate 2% until the pH increased to > 4.0. The effect of lavage on esophageal pH was compared using the Kruskal-Wallis and Wilcoxon 2 sample tests. Associations between lavage and pH changes were determined.

RESULTS

Of 48/112 dogs with strongly acidic GER, 33% neutralized their esophageal pH during surgery. For the 32 dogs that maintained an esophageal lumen pH value < 4, esophageal lavage with water increased the lumen pH to > 4 in 78.6% of dogs, whereas both bicarbonate concentrations increased it in 100% of the dogs to a more neutral pH (P < .0001). The dogs in the water group were more likely to regurgitate after anesthesia (36% vs 0% in both bicarbonate groups, P = .028).

CLINICAL RELEVANCE

Bicarbonate 1% and 2% increased esophageal lumen pH to more than 4 after strongly acidic GER. Lavage with water was mildly effective, but required large volumes and predisposed to further regurgitation after anesthesia.

A Comparative Assessment of the Diagnosis of Swallowing Impairment and Gastroesophageal Reflux in Canines and Humans

Swallowing impairment is a highly prevalent and clinically significant problem affecting people and dogs. There are myriad causes of swallowing impairment of which gastroesophageal reflux is the most common in both species. Similarities in anatomy and physiology between humans and canines results in analogous swallowing disorders including cricopharyngeus muscle achalasia, esophageal achalasia, hiatal herniation, and gastroesophageal reflux with secondary esophagitis and esophageal dysmotility. Accordingly, the diagnostic approach to human and canine patients with swallowing impairment is similar. Diagnostic procedures such as swallowing fluoroscopy, high-resolution manometry, pH/impedance monitoring, and endolumenal functional luminal imaging probe can be performed in both species; however, nasofacial conformation, increased esophageal length, and the difficulty of completing several of these procedures in awake dogs are inherent challenges that need to be considered. Human patients can convey their symptoms and respond to verbal cues, whereas veterinarians must rely on clinical histories narrated by pet owners followed by comprehensive physical examination and observation of the animal eating different food consistencies and drinking water. Dogs may also be unwilling to drink or eat in the hospital setting and may be resistant to physical restraint during diagnostic procedures. Despite the species differences and diagnostic challenges, dogs are a natural animal model for many oropharyngeal and esophageal disorders affecting people, which presents a tremendous opportunity for shared learnings. This manuscript reviews the comparative aspects of esophageal anatomy and physiology between humans and canines, summarizes the diagnostic assessment of swallowing impairment in both species, and discusses future considerations for collaborative medicine and translational research.

Anatomic characterization of the location of the esophageal ostium relative to the rima glottidis on CT in adult Labrador Retrievers

OBJECTIVE

To characterize the anatomic location of the esophageal ostium relative to the rima glottidis in adult Labrador Retrievers with the use of CT.

ANIMALS

98 CT scans of 75 adult Labrador Retrievers.

PROCEDURES

A search of the medical records database identified records of Labrador Retrievers that underwent CT of the head and neck between January 1, 2015, and December 31, 2018. Evaluators, blinded to each other's results, reviewed CT images and measured esophageal area at the level of the rima glottidis. For each dog, the left esophageal percentage (LEP) was calculated as the esophageal area left of the rima glottidis midline divided by the overall esophageal area at that level. Variables (age, sex, patient position, intubation status, and maxillary support during CT) were evaluated for association with LEP. The CT images of dogs that had multiple scans were assessed for within-patient variance.

RESULTS

Mean LEP was 56.2 ± 18.1% for all dogs. Only right lateral recumbency was significantly associated with LEP, with a lower LEP for dogs positioned in right lateral recumbency (42.4 ± 12.7%), compared with left lateral (63.0 ± 7.4%) or sternal (57.3 ± 18.8%) recumbency. No association was detected between LEP and other variables assessed. Eleven dogs had multiple CT scans; within-patient variance for LEP was ± 26.6%.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that, although most dogs had an LEP > 50%, the esophageal ostium was fairly centrally located in most dogs and may be more mobile than previously thought. Additional research is warranted to assess this mobility and whether the esophageal ostium location, relative to the larynx, affects the incidence of aspiration pneumonia in dogs undergoing surgical treatment for geriatric-onset laryngeal paralysis and polyneuropathy.

Esophagitis in Cats and Dogs

Esophagitis in cats and dogs is a consequence of increased exposure of the esophageal mucosa to gastroduodenal reflux. Causes can include anesthesia-related reflux, frequent vomiting, or lodged foreign bodies. An exception is eosinophilic esophagitis, an emerging primary inflammatory disease of the esophagus with a presumed allergic etiology. Reflux esophagitis owing to lower esophageal sphincter incompetence is often suspected; a tentative diagnosis can be made by endoscopic assessment, wireless esophageal pH-monitoring, or histologic examination. Because it can be difficult to distinguish diet-responsive upper gastrointestinal disease from esophagitis, response to treatment with gastric acid suppressants is needed to confirm the tentative diagnosis.

Effect of two different pre-anaesthetic omeprazole protocols on gastroesophageal reflux incidence and pH in dogs

OBJECTIVES

Gastroesophageal reflux can occur during anaesthesia and may lead to esophagitis and occasionally oesophageal stricture formation. The aim of the study is to assess two omeprazole protocols on gastroesophageal reflux incidence and pH in anaesthetised dogs.

MATERIALS AND METHODS

Fifty-five dogs undergoing elective ovariectomy were randomly assigned to: omeprazole single dose 1 mg/kg orally the evening before anaesthesia (20 dogs), omeprazole two doses 1 mg/kg orally the evening and 3 hours before anaesthesia (15 dogs), and control group that did not receive omeprazole (20 dogs). An oesophageal impedance/pH probe was used to measure gastroesophageal reflux incidence and pH during anaesthesia.

RESULTS

Gastroesophageal reflux was observed in 55% (11/20) of control dogs, 55% (11/20) of dogs receiving omeprazole once and 47% (7/15) of dogs receiving omeprazole twice. The incidence was not statistically significant different between groups. Gastroesophageal reflux pH (mean ± sd) was higher in dogs receiving omeprazole twice (6.3 ± 1.5), when compared to either control dogs (3.8 ± 1.1) or dogs receiving omeprazole once (4.1 ± 1.5). Strongly acidic reflux (pH < 4) was observed in 7% (1/15) of dogs receiving omeprazole twice versus 55% (11/20) and 35% (7/20) of control dogs and dogs receiving omeprazole once, respectively.

CLINICAL SIGNIFICANCE

Omeprazole administered the evening and 3 hours before anaesthesia increased gastroesophageal reflux pH and decreased the incidence of strongly acidic reflux in dogs. A single dose of omeprazole given the evening before anaesthesia had no effect on reflux pH.

A Systematic Review of the Methods of Assessment of Gastro-Oesophageal Reflux in Anaesthetized Dogs

Simple Summary

Regurgitation and gastro-oesophageal reflux (GOR) are common complications in dogs under anaesthesia. We reviewed the definitions and methods of GOR assessment in anaesthetized dogs published in 22 scientific papers to assess if studies were comparable (i.e., looking at the same thing). The definition of GOR implied the presence of fluids not reaching the mouth or nose in the oesophagus in all studies. Most studies measured the acidity in the oesophagus to state if fluids were present or not. The probes were not always placed in the same location and definitions varied. This means that it is complicated to compare findings of the different studies.

Abstract

We reviewed the definitions and methods of assessment of gastro-oesophageal reflux (GOR) in anaesthetized dogs. Three databases were used. Titles and abstracts were screened by two of the authors independently. A total of 22 studies was included in the analysis. The definition of GOR implied the presence of fluids not reaching the mouth or nose in the oesophagus in all studies. Most studies considered a change in pH using oesophageal pH meters as the sole method of assessment. Calibration of the pH probe was inconsistently reported. The position of the tip of the oesophageal probe was inconsistent and not always precisely described. The correct positioning in the intended location was verified in a limited number of studies. Some studies considered that GOR had happened for changes in pH below 4.0 or above 7.5 while others considered that GOR had happened when the pH dropped below 4.0 only. Some studies stated that the pH change had to be sustained for a minimum period of time (20 or 30 s) whereas others did not mention any duration. The variability of definitions and methods of assessment of GOR in anaesthetized dogs precludes meaningful comparison of the findings. Re-evaluation and uniformization of the methods appear necessary.

Aerodigestive Disease in Dogs

Aerodigestive disorders (AeroDs) in people encompass a wide range of clinical syndromes, reflecting the complex relationship between the respiratory and digestive tracts. In veterinary medicine, aspiration is used interchangeably with aspiration pneumonia. Although aspiration pneumonia is a common disorder in dogs, it does not reflect the breadth of AeroDs. Unfortunately, AeroDs rarely are investigated in veterinary medicine because of lack of clinical recognition, limitations in available diagnostics, and the fact that AeroDs may be caused by occult digestive disease. Recognizing patients with AerodD represents an area of significant clinical importance that may provide additional areas of clinical intervention.

Upper digestive tract abnormalities in dogs with chronic idiopathic lymphoplasmacytic rhinitis

BACKGROUND

Chronic idiopathic lymphoplasmacytic rhinitis (CILPR) is a common inflammatory disorder of unknown etiology affecting the nasal cavity of dogs. The diagnosis is made by exclusion of other causes of nasal disease and specific therapeutic protocols are lacking. In human medicine, a relationship between CILPR and gastrointestinal clinical signs has been postulated, and remission of respiratory signs after clinical trials with medications for gastrointestinal disorders has been observed.

OBJECTIVES

To describe history, clinical presentation, endoscopic and histopathologic concurrent respiratory and digestive tract abnormalities, and to evaluate improvement of respiratory signs after treatment for gastrointestinal signs.

ANIMALS

Twenty-five dogs with CILPR.

METHODS

Prospective study. For inclusion, following information had to be available: respiratory and digestive clinical signs, airway and digestive tract endoscopic abnormalities, histologic evaluation of respiratory and gastrointestinal tract biopsy specimens, and clinical response to different treatment strategies.

RESULTS

Twenty-two dogs had endoscopic gastrointestinal lesions, whereas 13 dogs had concurrent gastrointestinal signs. Most esophageal and duodenal endoscopic abnormalities were classified as moderate or severe. Respiratory and gastrointestinal tract histologic evaluation identified mostly chronic inflammation. Remission or marked improvement of respiratory signs was observed in the majority of dogs treated only for gastrointestinal signs up to 12 months after endoscopy. No significant associations between treatments and follow-up information were found.

CONCLUSION AND CLINICAL IMPORTANCE

Nasal and upper digestive tract abnormalities coexist in some dogs with CILPR. Lack of standardized therapeutic protocols suggests caution when interpreting improvement in nasal clinical signs. Additional studies are needed to explore the possibility of a cause-effect relationship between the 2 processes.

Late-onset laryngeal paralysis: Owner perception of quality of life and cause of death

Background

Late‐onset laryngeal paralysis (LoLP) is an idiopathic disease of older dogs, and is common in the Labrador Retriever. Owner perspective of how LoLP affects their pet's quality of life (QOL), the degree to which LoLP is perceived to be a life‐limiting disease, and how a glottic opening procedure affects these perceptions is not known.

Objectives

(a) To determine owner's perception of late‐onset laryngeal paralysis (LoLP) with respect to their dog's QOL; (b) To determine whether LoLP is considered by owners to be a life‐limiting disease; (c) To evaluate whether a glottic opening procedure altered QOL and perceived cause of death in affected dogs.

Methods

Owners of Labrador Retrievers with LoLP completed a questionnaire. Questions were asked pertaining to a dog's LoLP, including clinical progression and perception of cause of death, and whether a glottic opening procedure was undertaken. Owners also completed a pet‐owner administered QOL survey.

Results

Seventy‐six owners participated. Overall, 94% of owners felt their dog's LoLP affected QOL, and 47% of owners felt LoLP was a large contributing factor in their dog's death. Dogs that underwent a glottic opening procedure were reported to have a better QOL, and the contribution of LoLP towards their death was less than dogs that did not have surgery.

Conclusion

Owners of Labrador Retrievers with LoLP perceive LoLP to be a life‐limiting disease that negatively impacts their dog's QOL. Arytenoid lateralization surgery had a positive impact on QOL in affected dogs.

Laryngeal Disease in Dogs and Cats: An Update

Laryngeal diseases are manifested by obstructive breathing patterns reflecting functional or mechanical upper airway obstruction. Laryngeal paralysis is the most common disease of the larynx. Diagnosis requires close attention to anesthetic plane and coordination of respiratory effort with laryngeal motion. Surgical arytenoid lateralization improves clinical signs and quality of life in dogs; however, aspiration pneumonia is a recognized complication, and generalized neuropathy can progress. Laryngeal collapse can result from any cause of chronic upper airway obstruction but is most often associated with brachycephalic obstructive airway syndrome. Although uncommon, laryngeal neoplasia has a guarded to grave prognosis regardless of treatment.

Aerodigestive disorders in dogs evaluated for cough using respiratory fluoroscopy and videofluoroscopic swallow studies

Aerodigestive diseases, hybrid disorders representing a pathologic link between respiratory and alimentary tracts, may manifest with respiratory signs without gastrointestinal signs. These are underdiagnosed in dogs due to poor clinical recognition and diagnostic limitations. We hypothesize that a subset of dogs presenting for cough without gastrointestinal signs would have occult aerodigestive disorders identified using videofluoroscopic swallow study (VFSS). Data were retrospectively obtained from 31 client-owned dogs presenting for cough, with thoracic radiographs, and a VFSS between April 2015 and December 2017. Exclusion criteria were cough of cardiac origin or gastrointestinal signs within 6 months. Swallow study parameters included pharyngeal/esophageal motility, laryngeal obstruction/defects, penetration-aspiration, reflux, excessive aerophagia, megaesophagus (ME), lower-esophageal sphincter achalasia-like syndrome (LES-AS), and sliding hiatal hernia (HH). The median (interquartile range) duration of cough was 4 (2-8) months. Thoracic radiographs were unremarkable in 11 dogs, with aspiration pneumonia suspected in seven. In 25/31 dogs (81%), VFSS abnormalities were detected and some dogs had more than one defect: pharyngeal (n=10) or esophageal hypomotility (n=10), reflux (n=9), penetration-aspiration (n=8), excessive aerophagia (n=6), laryngeal obstruction (n=3), ME (n=3), HH (n=2), and LES-AS (n=1). A respiratory disorder causing cough was identified in 17 dogs with VFSS abnormalities (laryngeal obstruction/defect and airway disease including chronic or eosinophilic bronchitis, tracheal/mainstem bronchial collapse, bronchiectasis, and bronchomalacia). An alimentary disorder identified on VFSS in absence of a discrete respiratory disorder causing cough was diagnosed in eight dogs. In conclusion, canine aerodigestive disorders can manifest as cough without alimentary signs. VFSS is a useful diagnostic to determine the contribution of esophageal/gastrointestinal pathology in dogs with cough.

Reflux aspiration in lungs of dogs with respiratory disease and in healthy West Highland White Terriers

BACKGROUND

Gastroesophageal reflux and microaspiration (MA) of gastric juice are associated with various human respiratory diseases but not in dogs.

OBJECTIVE

To detect the presence of bile acids in bronchoalveolar lavage fluid (BALF) of dogs with various respiratory diseases.

ANIMALS

Twenty-seven West Highland White Terriers (WHWTs) with canine idiopathic pulmonary fibrosis (CIPF), 11 dogs with bacterial pneumonia (BP), 13 with chronic bronchitis (CB), 9 with eosinophilic bronchopneumopathy (EBP), 19 with laryngeal dysfunction (LD), 8 Irish Wolfhounds (IWHs) with previous BPs, 13 healthy WHWTs, all privately owned dogs, and 6 healthy research colony Beagles METHODS: Prospective cross-sectional observational study with convenience sampling of dogs. Bile acids were measured by mass spectrometry in BALF samples. Total bile acid (TBA) concentration was calculated as a sum of 17 different bile acids.

RESULTS

Concentrations of TBA were above the limit of quantification in 78% of CIPF, 45% of BP, 62% of CB, 44% of EBP, 68% of LD, and 13% of IWH dogs. In healthy dogs, bile acids were detected less commonly in Beagles (0/6) than in healthy WHWTs (10/13). Concentrations of TBA were significantly higher in CIPF (median 0.013 μM, range not quantifiable [n.q.]-0.14 μM, P < .001), healthy WHWTs (0.0052 μM, n.q.-1.2 μM, P = .003), LD (0.010 μM, n.q.-2.3 μM, P = .015), and CB (0.0078 μM, n.q.-0.073 μM, P = .018) groups compared to Beagles (0 μM, n.q.).

CONCLUSION AND CLINICAL IMPORTANCE

These results suggest that MA occurs in various respiratory diseases of dogs and also in healthy WHWTs.