Case report of brachycephalic obstructive airway syndrome in brachycephalic dogs from Veterinary Specialist Service Hospital, Australia

28 Nong Lam University, Ho Chi Minh City Case report of brachycephalic obstructive airway syndrome in brachycephalic dogs from Veterinary Specialist Service Hospital, Australia Phuc N. Le1, Thong Q. Le1∗, & Philip Moses2 1Faculty of Animal Science and Veterinary Medicine, Nong Lam University, Ho Chi Minh City 2Veterinary Specialist Service Hospital, Underwood, Queensland, Australia ARTICLE INFO Research Paper Received: March 04, 2020 Revised: May 15, 2020 Accepted: June 19, 2020 Keywords Brachycephalic syndrome BOAS Brachycephalic dogs ∗Corresponding author Le Quang Thong Email: lqthong@hcmuaf.edu.vn ABSTRACT This report aimed to study symptoms and causes of brachycephalic obstructive airway syndrome (BOAS) in brachycephalic dogs and to determine appropriate surgical procedures for these symptoms by reviewing literatures and examining four case studies conducted at Veterinary Specialist Service Hospital, Underwood, Queensland, Australia. The cases included a 6-year 3-month old Staffordshire Bull Terrier (case 1), a 1-year 5-month old French Bulldog (case 2), an 8-month old French Bulldog (case 3), and an 8-year 8-month Pug (case 4). Those dogs went to the Veterinary Specialist Service in a worsen state of respiratory problems, including the upper respiratory noise (case 1, 2, 3), decrease in exercise tolerance, respiratory struggling (case 1, 3), regurgitation (case 1), coughing, sleeping difficulty, respiratory stridor (case 2), nasal discharge, dyspnea, bloating, and tachypnea (case 4). Examinations revealed the causes including the elongated soft palate (case 1, 2, 3, 4), stenotic nostrils (case 2, 3, 4), tonsils inflammation (case 3) and everted laryngeal saccules (case 4). After surgery, the dogs were recovered in intensive care unit within 2 days, and then discharged. Scheduled re-examination one week later showed improvement in the respiratory health in all cases. Overall, major complications occur in 10% of cases; however, this surgery is vital and can be totally applied in Vietnam where brachycephalic dogs have become a popular companion. Cited as: Le, P. N., Le, T. Q., & Philip Moses. (2020). Case report of brachycephalic obstructive airway syndrome in brachycephalic dogs from Veterinary Specialist Service Hospital, Australia. The Journal of Agriculture and Development 19(3), 28-38. 1. Introduction Congenitally, brachycephalic dogs are char- acterized with a shortened head, which is brachycephalic syndrome also known as brachy- cephalic conformation of the skull (Bjorling et al., 2000). The syndrome consists of anatomic abnormalities including stenotic nares, tortu- ous turbinates, caudally displaced maxillae, elon- gated soft palate, everted laryngeal saccules, and hypoplastic trachea (Ackerman, 1999; Koch et al., 2003). The abnormal skull’s anatomy nar- rows the lumen of upper respiratory tract, thus lead to asphyxiation and collapse during excite- ment, hot weather or exercises (Koch et al., 2003; Packer et al., 2012). Moreover, the dis- placed maxillae and the elongated soft palate in- terfere with laryngeal functions resulting in res- piratory stridor, open-mouth breathing, inspira- tory dyspnea, exercise intolerance, noisy breath- ing, suffocating and coughing (Ackerman, 1999; Dupre, 2008). According to skull measurements, the typical brachycephalic breeds include Chi- huahua, Bulldog, King Charles Spaniel, Pug, Boston Terrier, Maltese, Pekingese, Miniature Pinscher, Shih Tzu, Yorkshire Terrier, and Boxer, The Journal of Agriculture and Development 19(3) www.jad.hcmuaf.edu.vn Nong Lam University, Ho Chi Minh City 29 Lhasa Apso, Shar Pei (Koch et al., 2003). In re- cent years, the brachycephalic dogs have become the popular breeds in many countries as well as in Vietnam, which inevitably leads to an increase in BOAS cases (Best et al., 2016). Treatment-wise, hypoplastic trachea, fore- shortened maxillae, and narrow rima glottidis are unchangeable. For the case of tortuous turbinate, the surgery can remove a little piece in turbinate to make the airway more ventilated but it is dan- gerous and expensive with long surgical time. However, the surgery can also affect the patient’s olfactory ability, therefore, it is often deemed unnecessary. For the remaining anomalies, there are safer procedures to relieve the symptoms of BOAS, which include trimming the stenotic nares, resecting the elongated soft palate, removal of the everted laryngeal saccules, and removal of the tonsils (depending on the specific situation). In general, the surgery of stenotic nares includes nares amputation, wedge resection (alarplasty) and alapexy (Fossum, 2013). Specif- ically, in wedge resection, stenotic nares are re- sected easily by cutting the V-shaped section of the nares with the No.11 scalpel blade. Wedge re- section is less surgical time than alapexy, less in- cisional bleeding than amputation. However, this procedure can be failed if flaccidity of the carti- lage occurs, mobility of the dorsolateral cartilage increases, depigmentation or asymmetrical nose presents. Resection of elongated soft palate is nor- mally performed using Metzenbaum scissor. Elec- trosurgery can also be used instead; however, may cause swelling in post-operative care. In some cases that tonsils inflamed or obstruct the airway, tonsils can be removed by Metzenbaum scissor or scalpel blade. Then, at the base of the everted tis- sue, using the tip of a long-handled, curved Met- zenbaum scissors transects the everted laryngeal saccules. To determine which surgical procedures are suitable for the patients, clinical examination and diagnosis are conducted. In clinical examination, the stenotic nares, the size of the trachea and the obstructive inspiratory dyspnea with stertor can be determined by observation and palpation. After that, diagnostic radiography and bron- choscopy rule out abnormal respiratory and car- diology diseases. The surgical procedure should be performed as soon as possible for dog that is above 4 months of age since the nasal tissues are mature enough to hold sutures. 2. Materials and Methods 2.1. Case 1 2.1.1. History Dog 1 was a six-year-three-month-old male neutered Staffordshire bull terrier breed dog. Noisy breathing was observed by owner; how- ever it became worse during the past year, to- gether with exercise intolerance, heat intolerance, and respiratory struggle during excitement. The dog would occasionally regurgitate white foam, despite eating and drinking normally without coughing or sneezing, or changing in bark. 2.1.2. Clinical examination Clinical examination revealed lean body condi- tion, noticeable upper respiratory noise, pink mu- cous membrane, good airflow through both nos- trils; elongated soft palate was observed. Based on the result, the dog was diagnosed with signs of BOAS. The obstruction of airway was likely due to elongated soft palate and small probabil- ity of laryngeal paralysis, with recommendation for BOAS surgery and arytenoid lateralization. 2.1.3. Laboratory test The result of the blood test was 37% and 70 for packed cell volume and total protein respectively, which is ordinary according to the normal range of PCV (37-55%) and normal range of TP (55- 75). This test is quick, easy and it is a common preoperative test because it gives information of the patient’s status about anemia, blood protein, hydration status. 2.1.4. Radiograph Findings in thoracic radiographs were unre- markable (Figure 1). The result of imaging di- agnosis showed that there were no cardiology and respiratory problems such as heart base tu- mor, nasopharyngeal, laryngeal, tracheal masses; and secondary changes to the lungs, such as bronchiectasis and probable hypoplastic trachea. 2.1.5. Bronchoscopy The upper airway was examined with bron- choscopy showing the arytenoids moved bilater- www.jad.hcmuaf.edu.vn The Journal of Agriculture and Development 19(3) 30 Nong Lam University, Ho Chi Minh City Figure 1. The right lateral thorax radiography (Dog 1). Ventral side (a), Perihilar (b), Dorsocau- dal (c) and diffuse of lungs assessed for bronchopneu- monia, especially aspiration pneumonia, pulmonary edeama, pulmonary haemorrhage. Vertebral heart size (VHS)= 8 (< 10.7), heart size was normal. Tra- cheal hypoplasia was rejected (black line) and no hia- tus hernia, no abnormalities in vertebral body. ally, hence arytenoid lateralization was deemed unnecessary. 2.1.6. Surgery The surgical procedure included general anes- thesia, upper airway exam, thoracic radiographs and elongated soft palate resection. The patient was then pre-oxygenated for 5-10 minutes and slowly induced with Alfaxalone 30mg IV, and in- tubated with a cuffed ET tube. Circulation, heart rate, oxygenation, ventilation, blood pressure val- ues including systolic arterial pressure, diastolic arterial pressure, mean arterial pressure and the anesthetic maintenance was updated every five minutes using intraoperative monitoring system. First, the patient was placed in sternal recum- bency with the mouth fully opened and the chin was not allowed to have contact with the table’s surface. Next, the mucosal surfaces should not be scrubbed to protect from irritation and edema; the endotracheal tube was secured to the lower jaw ensuring free access to the soft palate. Then, the surgeon began to scrub and prepared the soft palate kit when everything was in position (Fig- ure 2). Figure 2. List of surgical instruments for BOAS surgery. For elongated soft palate resection, the resec- tion was done with scissors, the surgeon placed stay suture of 3-0 Monocryl at the proposed site of resection. Next, the surgeon resected one third of the soft palate with Metzenbaum scis- sor, then apposed the mucosa with 3-0 Monocryl simple continuous suture pattern; the procedure was then repeatedly continued between excision and suturing until the resection was completed (Figure 3). During the resection, there was mild hemorrhage, which was put under control by ty- ing a swab to a thread and placed the swab in the surgical area. 2.1.7. Post-operative care After surgery, the patient was moved to the Pet intensive care unit (PICU) to recover overnight with close monitoring. Postoperative care in- cluded the late extubation, analgesic protocol, nasal oxygen supplementation, close monitoring of the breathing. Upper airway obstruction in post-surgery was concerned due to inflamma- tion and swelling. After surgery, Medetomidine was needed for anxiety, with transition to Tra- madol Oral the next day. Post-surgery medica- tions: Methadone 0.1 - 0.2 mg/kg SC and Medeto- midine CRI at 1 µg/kg/h. After 2 days in the PICU, the dog swallowed the food trial and was discharged. 2.2. Case 2 2.2.1. History A one-year five-month-old female French bull- dog was examined for a history of some upper res- piratory noise and coughing. The dog ate quickly and sometimes slightly choked on food. Other- while, the dog had not shown any significant res- piratory difficulty. The Journal of Agriculture and Development 19(3) www.jad.hcmuaf.edu.vn Nong Lam University, Ho Chi Minh City 31 Figure 3. Elongated soft plate resection (Dog 1). (a) Transected one-third of the palate, then (b) apposed the mucosa with sutures. (c) Continue alternating excision and suturing until the resection was completed (Bjorling et al., 2000). 2.2.2. Clinical examination On initial physical examination, the dog pos- sessed congenital traits of brachycephalic breeds. Due to observational heavy open-mouth breath- ing, respiratory stridor, and difficulty sleeping, elongated soft palate was considered as a main cause. The dog nostrils were congenital stenotic. Thoracic auscultation showed normal cardiac and bronchovesicular sounds, however there was a slight upper airway noise. Based on clinical exam- ination, the first diagnosis was BOAS and surgery therapy was recommended. www.jad.hcmuaf.edu.vn The Journal of Agriculture and Development 19(3) 32 Nong Lam University, Ho Chi Minh City 2.2.3. Laboratory test The result of PCV/TP was normal at 45/74 based on normal range. 2.2.4. Radiograph The radiograph was conducted to detect other diseases; especially aspiration pneumonia because of the dog’s eating routine. The findings were un- remarkable (Figure 4). Figure 4. The right lateral thorax radiography (Dog 2). No hiatus hernia, no abnormalities in vertebra, lungs, trachea. Heart size was normal (VHS = 9 < 10,7). 2.2.5. Bronchoscopy During bronchoscopy, laryngeal paralysis was ruled out; no laryngeal saccules were observed. Main bronchus and secondary bronchi were ob- served no abnormalities (Figure 5). 2.2.6. Surgery The treatment regimen included the resection of elongated soft palate and the resection of stenotic nares. During soft palate resection surgery, a stay suture of 4-0 Monosyn was placed in the cau- dal midpoint of the soft palate, allowing it to be pulled rostrally. Two additional stay sutures were placed to either side of the soft palate to mark the intended line of resection, level with the caudal tonsillar crypts. The left side of the soft palate was cut with Metzenbaum scissors, then 4-0 Monosyn simple continuous pattern was used to appose the nasal and oral mucosal cut edges of the soft palate. The process was repeated to re- move the remaining soft palate. Next, for stenotic nares resection, wedge resection was performed to permanently enlarge the external nares. Using an 11 scalpel blade, a triangular wedge of tis- sue was removed from the lateral aspect of the nares. Closure was achieved with 4-0 Monocryl, absorbable sutures placed in a simple interrupted pattern (Figure 6). 2.2.7. Post-operative care After surgery, dog 2 was moved to the PICU for recovery. IV Hartmann’s was maintained, meloxi- cam 1.5 mg/mL was used once per day when eating to reduce postoperative inflammation and pain; cephalothin 1 g/mL IV was supplied. Day 2 in PICU, the patient was stable and swallowed the food trial. The patient was discharged and went back home with administered meloxicam 1.5 mg/mL once per day. 2.3. Case 3 2.3.1. History An eight-month-old male neutered French bull- dog was examined for a history of upper respira- tory noise with decreased exercise tolerance. Sim- ilar to case 1, the dog struggled on hot days and during excitement. The main presenting problem was mild upper respiratory stertor. 2.3.2. Clinical examination The dog possessed anatomic abnormality of brachycephalic dog breeds, false positioning of the teeth, open-mouth breathing. Thoracic aus- cultation showed normal cardiac and bron- chovesicular sounds. Based on clinical examina- tion, the dog was diagnosed with BOAS. 2.3.3. Laboratory test The result of PCV/TP was normal at 33/70 based on normal range. The Journal of Agriculture and Development 19(3) www.jad.hcmuaf.edu.vn Nong Lam University, Ho Chi Minh City 33 Figure 5. Bronchoscopy (Dog 2). Images of (a) main bronchus and (b) secondary bronchi showed no abnor- malities. 2.3.4. Radiograph Imaging diagnosis showed no other problems (Figure 7). 2.3.5. Bronchoscopy Oral examination showed the inflammation of tonsils, moderate elongation of soft palate and bronchoscopy showed erythema around ary- tenoids; there was no evidence of laryngeal sac- cule eversion or laryngeal collapse, laryngeal paralysis was ruled out. 2.3.6. Surgery According to diagnosis, the surgeon decided on resection of stenotic nares, resection of elongated soft palate, and tonsils removal. During resec- tion of elongated soft palate, the tip of the soft palate was grasped with allis tissue forceps and a stay suture placed at the site of resection for ma- nipulation. The soft palate was resected approx- imately one third of the width of the soft palate with Metzenbaum scissors. Closure achieved us- ing 4-0 Monosyn in a simple continuous suture pattern. During resection of stenotic nares, the margin of the nares was grasped with forceps. A V shaped incision was made medially and the sec- ond incision laterally. The wedge of tissue was re- moved and haemorrhage controlled with pressure. The ventral margin of the nares and the mucocu- taneous junction were aligned and sutured closed using 4-0 Monosyn in a simple continuous pat- tern. For Dog 3, the airway was too small, the tonsils were tonsillitis, obstructed the airway. The surgeon proceeded to remove the protruded ton- sils (Figure 8). 2.3.7. Post-operative care After surgery, the dog was moved to the PICU. The dog was noted allergic to Cephalothin, recov- ered well from anesthesia and surgery, had one re- gurgitation but was comfortable. The dog contin- ued to be hospitalized in ICU overnight for close monitoring post brachycephalic general anaesthe- sia and was monitored for risk of aspiration pneu- monia. Day 2 in PICU, the dog swallowed food trial well, was bright and alert. Dog 3 showed no regurgitation or emesis, but did have an episode of hypersalivation which was responsive to Maro- pitant administration which was used the pre- vious night. The patient went back home with Meloxicam 0.1 mg/kg PO SID when eating. 2.4. Case 4 2.4.1. History Dog 4 was an eight-year eight-month-old fe- male Pug with a history of hemivertebrae and ataxia problems. The dog had a surgery to place plate and decompress at two-year old. Based on the hospital transfer record of Dog 4, carprofen injection was used for reducing spinal pain. In the present time, the dog had nasal discharge, dyspnea and bloating; these episodes gradually became more serious and worsened. www.jad.hcmuaf.edu.vn The Journal of Agriculture and Development 19(3) 34 Nong Lam University, Ho Chi Minh City Figure 6. Trimming of stenotic nares (Wedge resection) (Dog 2). (A) Made a V-shaped incision around the forceps with a No. 11 scalpel blade, the first incision was located medially and the second incision laterally. (B) Closed incisions with 4-0 Monocryl, absorbable sutures placed in a simple interrupted pattern (Bjorling et al., 2000). 2.4.2. Clinical examination Tachypnea and moderate respiratory effort were observed. The nares were narrowed, al- though not severely. Upper respiratory tract noise was increased. The dog was examined in four days later for as- sessment of BOAS following an episode of acute dyspnea and bloating before. At this point, clin- ical signs were consistent with secondary airway obstruction to BOAS. The obstruction was likely associated with elongated soft palate, stenotic The Journal of Agriculture and Development 19(3) www.jad.hcmuaf.edu.vn Nong Lam University, Ho Chi Minh City 35 Figure 7. The left lateral thorax radiography (Dog 3). Heart size was normal (VHS = 9 < 10,7). No hiatus hernia, no abnormalities in lungs, trachea. Figure 8. Tonsillectomy (Red lines). Tonsils are re- moved by forceps and Metzenbaum scissor (Ward & Hunter, 2009). nares and secondary airway abnormalities. Fur- thermore, the bloating and associated dyspnea noted might also be in part due to gastrointesti- nal causes, such as a hiatal hernia. Other causes of airway obstruction or respiratory distress could not be ruled out but were investigated prior to surgery. 2.4.3. Laboratory test The PCV/TP test result was normal at 40/70. The ALT in biochemical blood test was higher than normal and this was a caution to use medicine in its treatment (Table 1). Table 1. The result of biochemistry test (Dog 4) Test Result Unit Lowestvalue Highest value HEM 29.0 LIP 109.0 ICT 0.0 ALB 37.0 g/L 25.0 44.0 ALP 33.0 U/L 20.0 150.0 ALT 156* U/L 10.0 118.0 AMY 464.0 U/L 200.0 1200.0 TBIL 4.0 µmol/L 2.0 10.0 BUN 6.1 mmol/L 2.5 8.9 CA 2.64 mmol/L 2.15 2.95 PHOS 1.27 mmol/L 0.94 2.13 CRE 82.0 mmol/L 27.0 124.0 GLU 5.1 mmol/L 3.3 6.1 NA+ 147.0 mmol/L 138.0 160.0 K+ 4.6 mmol/L 3.7 5.8 TP 74.0 g/L 54.0 82.0 GLOB 37.0 g/L 23.0 52.0 2.4.4. Radiograph Radiographs revealed some evidence of peri- implant lucency which was suggestive of loss of implant stability, but surgical site comfort and palpation was unremarkable (Figure 9). Lung fields were normal with no evidence of aspiration pneumonia. 2.4.5. Bronchoscopy Evaluation of the pharynx showed a small cen- tral white nodule; different diagnosis was likely an inflammatory nodule. www.jad.hcmuaf.edu.vn The Journal of Agriculture and Development 19(3) 36 Nong Lam University, Ho Chi Minh City Figure 9. The right lateral thorax radiography (Dog 4). Radiography showed no abnormalities in trachea, lungs, heart, no hiatus hernia. Based on the hospital transfer record, the dog had surgical treatment of hemivertebrae. 2.4.6. Surgery Surgery was recommended for the dog to re- duce resistance to inspiration by conducting a combination of alarplasty, soft palate resection and laryngeal sacculectomy if required. First, in staphylectomy, right angle forceps were used for positioning the soft palate and resected using Metzenbaum scissors. Closure achieved using 4-0 Monocryl simple continuous suture pattern. Sec- ond, in removal of the laryngeal saccules, the sur- geon temporarily extubated Dog 4. The everted laryngeal saccules were cut off with Metzenbaum scissors (Figure 10). Last, trimming of stenotic nares was performed. A wedge resection of the nares was removed using an 11 scalpel blade. Clo- sure was achieved using 4-0 Monocryl simple in- terrupted suture pattern. 2.4.7. Post-operative care After surgery, the dog recovered quickly from anaesthetic but then the dog presented dyspnea; thus the oxygen supplement was used. The dog The Journal of Agriculture and Development 19(3) www.jad.hcmuaf.edu.vn Nong Lam University, Ho Chi Minh City 37 Figure 10. Resection of everted laryngeal saccules (Dog 4). Using Metzenbaum scissor cut off the everted laryngeal saccules (Fossum, 2013). initially only got inspiratory flow with its mouth held open and tongue out. As recovered from anaesthetic, inspiratory flow was improved but continued to have occasional episodes where the dog retched and moved but then recovered it- self. Day 2 in PICU, the dog swallowed the food trial in the morning and then was discharged with omeprazole 10 mg tablet to be given a half twice a day. For the first couple of days, the dog had some difficulty breathing through the nose result- ing in self-waking during sleep, causing sleep dif- ficulty. After day 3, the problem was resolved, the dog started to breath well and the gastric reflux seemed to be settled. 3. Discussion Surgery for BOAS should be planned in the morning, after that, observation is recom- mended for all day. In post-operative care, surg- eries complications include bleeding, swelling, edema, wound problems, aspiration pneumo- nia and even death. Furthermore, post-operative problems can become more complicated, lead to difficulty breathing and respiratory distress (Fos- sum, 2013). It is treated, depending on sever- ity, with a combination of sedation, oxygen ther- apy, intubation, temporary or permanent tra- cheostomy or mechanical ventilation (Holt et al., 1994; O’Dwyner, 2017). Those sort of major com- plications occurred in 10% of cases, and a small number of dogs do not survive to discharge, typ- ically due to severe aspiration pneumonia. 4. Conclusions BOAS is a set of health problems, mainly in the upper respiratory system, that present pre- dominantly in brachycephalic dog breeds. This is the result of congenital malformation of the skull of such breeds leading to various anatomi- cal abnormalities including stenotic nares, tortu- ous turbinates, caudally displaced maxillae, elon- gated soft palate, everted laryngeal saccules, and hypoplastic trachea. These abnormalities conse- quently cause obstruction in nasal cavity, lar- ynx and/or pharynx. Dogs with BOAS may show signs of having respiratory noises, observable nostril stenosis, eating difficulties, regurgitation, sleep dyspnea, sleep apnea, heat intolerance, ex- ercise intolerance and/or collapsing. Correspond- ingly, the main focus of BOAS surgeries is to unblock the airway. Surgical procedures may in- clude staphylectomy for the case of elongated soft palate, laryngeal sacculectomy for the case of ev- erted laryngeal saccules, alarplasty for the case of stenotic nares, and tonsillectomy for the case of everted/hypertrophy tonsils. Postoperative re- sults from the case studies show the clear im- provement in respiratory health in all discussed www.jad.hcmuaf.edu.vn The Journal of Agriculture and Development 19(3) 38 Nong Lam University, Ho Chi Minh City cases. References Ackerman, L. J. (1999). The genetic connection: a guide to health problems in purebred dogs (1st ed.). Colorado, USA: American Animal Hospital Association. Best, S., Duffin, C., & Ward, A. (2016). Think twice before getting bulldogs or pugs: Demand for ’flat-faced’ canines could damage their health, warn vets. Retrieved May 22, 2020, from https://www.dailymail.co.uk/sciencetech/article- 3799981/Think-twice-getting-bulldogs-pugs-Vets-say- demand-flat-faced-canines-damage-health.html. 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