小動物耳鼻喉暨臨床睡眠研究室 -短吻犬阻塞性呼吸道症候群

手機版選單

下方連結

短吻犬阻塞性呼吸道症候群

Art editor Img

短吻犬阻塞性呼吸道症候群（Brachycephalic obstructive airway syndrom, BOAS）為好發在短吻犬種（或稱短顱犬種）如巴哥犬、法國鬥牛犬、英國鬥牛犬、北京犬、西施犬、布魯賽爾格林芬犬等，表型相關之阻塞性上呼吸道疾病。在數百年針對人們所喜好之「扁臉（或短吻）」特徵育種篩選下頭骨長軸縮短（寬而短的頭顱），然頭骨內軟組織卻沒有等比例地縮小，進而造成上呼吸道的阻塞。不同短吻犬品種的 BOAS 盛行率不一，在台灣統計呼吸功能分級（Respiratory function grading scheme）截至2024年6月，目前在法國鬥牛犬 BOAS 盛行率約為 50%。其他短吻品種如西施犬則是盛行率較低的品種。

極短吻特徵的繁殖下，除了上呼吸道擠壓造成呼吸困難外，後頭顱的構造亦造成擠壓，造成外耳道及鼓室，在某些品種更會造成脊髓空動症（Syringomyelia）及類奇亞里畸形（Chiari-like malformation）等因顱頸交界畸形所導致的神經性疾病。

一般在幼年動物（六個月以內）並不會出現 BOAS 相關症狀，然而隨著年齡增長，軟組織量相對增加，顱骨變寬，患病犬隻會在一歲左右開始出現呼吸道阻塞之症狀如異常的呼吸音、呼吸用力、運動不耐、發紺甚至暈厥等，此外其他與上呼吸道阻塞相關之臨床症況亦包括嘔吐反流、不耐熱等，在嚴重狀況下可能影響犬隻生活品質及生命。統計上有近60%患病犬隻的飼主並不知道自己的犬隻患有 BOAS，因此往往有延誤治療、進而造成病灶及症狀加劇，甚至不可逆的狀況。

BOAS 的治療以體重控制及外科介入為主，呼吸道校正手術項目會依診斷之病灶而執行。術後最常見的併發症為吸入性肺炎及術後軟組織腫脹，然在穩定後絕大部分病患在術後兩週內可恢復正常生活，並有好的預後。不過，手術並不能完全「治癒」BOAS，只能夠改善阻塞。控制 BOAS 育種的選擇極為重要，不論是獸醫師、飼主、寵物業者及繁殖業者都應該要能辨認 BOAS 的症狀以及相關表型風險因子（如極短吻、頸部粗短、頭顱過寬等），拒絕患病犬隻納入繁殖計畫內，才能有效降低疾病盛行率。

病生理學
臨床症狀
臨床診斷
治療及預後
病生理學

短吻犬阻塞性呼吸道症候群（Brachycephalic Obstructive Airway Syndrom, BOAS）是一種好發於某些短顱犬品種的上呼吸道相關症候群。由於蝶枕聯合軟骨的提早閉合而出現「短顱」、「短鼻」、「短吻」的特徵 [1, 2]。經過長期的人為育種選擇，短顱犬的頭顱變的又寬、又短，然而頭顱裡的軟組織（如呼吸道）沒有一起跟著一起改變，反而被不正常的壓縮以及異常生長（如鼻甲增生），進而造成上呼吸道的阻塞。

從西元1910年至今，短頭犬的頭骨形狀變得更短、更寬 [3]，短顱犬面部更平坦，且短吻犬經過育種後，其臉部特徵與人類嬰兒的臉部特徵相似，有雙圓圓的大眼睛、平坦的臉、寬大的額頭，讓短顱品種犬更受歡迎。根據研究統計，許多飼主在一開始購買犬隻時，只考量犬隻可愛的外觀，並未考慮到短吻犬動物福利以及其他所衍生的問題。

近親繁殖造成「基因庫窄化」，進階影響狗狗的免疫功能，造成狗狗更容易易受病原體感染或是產生自體免疫疾病 [4]。這些短顱特徵也會造成呼吸問題、眼睛疾病、皮膚病、難產、齒科和心臟問題 [4]。

英國鬥牛犬、法國鬥牛犬和巴哥犬等極端短顱品種犬有相當多的健康問題。英國鬥牛犬(English Bulldog)最初培育的目的就是為了「鬥牛」，因而育種出以下特徵：「突出的下顎」以及「強大的咬合力」；「皮膚皺摺」可以保護臉部重要的血管；「寬闊的四肢」顯得更為強壯。然而，這些身體特徵反而會導致「皮摺發炎」、「眼瞼腺體脫垂」和「戽斗」等問題 [5]。在生產時，由於英國鬥牛犬的頭骨過大而無法順利於通過骨盆，因此往往需要剖腹產 [6]。

法國鬥牛犬和巴哥犬因其嬰兒般的外貌而激發人類的母愛 [7]。法國鬥牛犬最初是由玩具鬥牛犬和其他梗犬育種而來 [8]。法國鬥牛犬常見的疾病包括短顱犬阻塞性呼吸道症候群（BOAS）、外耳炎、中耳炎、皮褶炎、難產 [9,10]。

巴哥犬曾經是中國皇室的玩賞犬 [11]。巴哥犬常見的疾病包括短吻犬阻塞性呼吸道症候群、肥胖、眼瞼內翻、角膜病變、外耳炎 [12,13,14]。

1. Julian, L.M.; Tyler, W.S.; Hage, T.J.; Gregory, P.W. Premature closure of the spheno‐occipital synchondrosis in the horned Hereford dwarf of the “short‐headed” variety. Am. J. Anat. 1957, 100, 269–287, doi:10.4324/9780203125236-39.

2. Schmidt, M.J.; Volk, H.; Klingler, M.; Failing, K.; Kramer, M.; Ondreka, N. Comparison of closure times for cranial base synchondroses in mesaticephalic, brachycephalic, and cavalier king charles spaniel dogs. Vet. Radiol. Ultrasound 2013, 54, 497–503, doi:10.1111/vru.12072.

3. Koch, D.A.; Sturzenegger, N. Veränderung des Schädels bei brachycephalen Hunden im Verlaufe der letzten 100 Jahre. Kurzmitteilungen | Short Commun. 1 SAT | ASMV 2015, 3, 2014–2016.

4. Packer, R.; O’Neill, D. Health and welfare of brachycephalic (flat-faced) companion animals: a complete guide for veterinary and animal professionals; CRC Press, 2021; ISBN 0429553811.

5. O’Neill, D.G.; Skipper, A.; Packer, R.M.A.; Lacey, C.; Brodbelt, D.C.; Church, D.B.; Pegram, C. English Bulldogs in the UK: a VetCompass study of their disorder predispositions and protections. Canine Med. Genet.2022, 9, 1–14, doi:10.1186/s40575-022-00118-5.

6. Ekenstedt, K.J.; Crosse, K.R.; Risselada, M. Canine Brachycephaly: Anatomy, Pathology, Genetics and Welfare. J. Comp. Pathol. 2020, 176, 109–115, doi:10.1016/j.jcpa.2020.02.008.

7. Paul, E.S.; Packer, R.M.A.; McGreevy, P.D.; Coombe, E.; Mendl, E.; Neville, V. That brachycephalic look: Infant-like facial appearance in short-muzzled dog breeds. Anim. Welf. 2023, 32, doi:10.1017/awf.2022.6.

8. Neill, D.G.O.; Baral, L.; Church, D.B.; Brodbelt, D.C.; Packer, R.M.A. Demography and disorders of the French Bulldog population under primary veterinary care in the UK in 2013. 2018, 1–12.

9. O’Neill, D.G.; Packer, R.M.A.; Francis, P.; Church, D.B.; Brodbelt, D.C.; Pegram, C. French Bulldogs differ to other dogs in the UK in propensity for many common disorders: a VetCompass study. Canine Med. Genet. 2021, 8, 1–14, doi:10.1186/s40575-021-00112-3.

10. O’neill, D.G.; O’sullivan, A.M.; Manson, E.A.; Church, D.B.; Boag, A.K.; Mcgreevy, P.D.; Brodbelt, D.C. Canine dystocia in 50 UK first-opinion emergency care veterinary practices: Prevalence and risk factors. Vet. Rec. 2017, 181, 88, doi:10.1136/vr.104108.

11. Moses, P.A. Welfare of Brachycephalic Dogs. North Am. Vet. Conf. 2016, 359–363.

12. O’Neill, D.G.; Darwent, E.C.; Church, D.B.; Brodbelt, D.C. Demography and health of Pugs under primary veterinary care in England. Canine Genet. Epidemiol. 2016, 3, 1–12, doi:10.1186/s40575-016-0035-z.

13. Asher, L.; Diesel, G.; Summers, J.F.; McGreevy, P.D.; Collins, L.M. Inherited defects in pedigree dogs. Part 1: Disorders related to breed standards. Vet. J. 2009, 182, 402–411, doi:10.1016/j.tvjl.2009.08.033.

14. Packer, R.M.A.; Hendricks, A.; Burn, C.C. Impact of facial conformation on canine health: Corneal ulceration. PLoS One 2015, 10, 1–16, doi:10.1371/journal.pone.0123827.
臨床症狀

BOAS的臨床症況包括呼吸異常、呼吸困難、運動耐受性差、熱耐受性差、睡眠障礙、反流、嘔吐和發紺 [1–5].

BOAS的解剖特徵包括鼻孔狹窄、軟顎過長、鼻甲增生、扁桃體外翻、喉小囊外翻和喉頭塌陷 [6]。上呼吸道異常的解剖結構增加了氣道的負壓，進而導致鼻黏膜增生、氣道變窄，最終造成喉頭塌陷 [7]。

鼻孔狹窄容易導致鼻氣道阻塞 [7]，約有50%～100%的短顱犬有鼻孔狹窄的問題 [8]。在患有BOAS的顱犬中，約有86%～94%犬隻有軟顎過長而導致氣道阻塞的問題 [9,10]，這個問題也使軟齶肌肉(palatine muscle)變得脆弱，最終導致鼻咽部塌陷 [11]。

短顱犬的呼吸道阻塞還會影響「胃腸道」和「心血管系統」。研究發現，74%的短顱犬同時出現呼吸和胃腸道症狀 [12,13]。上呼吸道阻塞會增加胸腔負壓增而導致反流和嘔吐。與BOAS相關的胃腸道病變包括「食道裂孔疝氣」、「幽門狹窄」和「食道位移」。若不進行相關治療，可能會發展成「肺高壓」和「右心衰竭」，而產生生命危險 [14]。

BOAS的發病率估計約為20-40%，短顱犬的預期壽命比其他犬種少3-4年 [15]。雖然極端短顱犬的BOAS發病率很高，約有60%的飼主認為犬隻BOAS臨床症狀屬於「正常現象」[16]。這個現象也影響了動物福利，許多BOAS的犬隻若未接受治療，可能會遭受吸不到空氣、胃酸逆流和睡眠不足之苦。

1. Roedler, F.S.; Pohl, S.; Oechtering, G.U. How does severe brachycephaly affect dog’s lives? Results of a structured preoperative owner questionnaire. Vet. J. 2013, 198, 606–610, doi:10.1016/j.tvjl.2013.09.009.

2. Robertshaw, D. Mechanisms for the control of respiratory evaporative heat loss in panting animals. J. Appl. Physiol. 2006, 101, 664–668, doi:10.1152/japplphysiol.01380.2005.

3. Lilja-Maula, L.; Lappalainen, A.K.; Hyytiäinen, H.K.; Kuusela, E.; Kaimio, M.; Schildt, K.; Mölsä, S.; Morelius, M.; Rajamäki, M.M. Comparison of submaximal exercise test results and severity of brachycephalic obstructive airway syndrome in English bulldogs. Vet. J. 2017, 219, 22–26, doi:10.1016/j.tvjl.2016.11.019.

4. Venker-van Haagen, A. Ear, nose, throat, and tracheobronchial diseases in dogs and cats; Schlütersche, 2010; ISBN 3899930932.

5. Della Maggiore, A. An Update on Tracheal and Airway Collapse in Dogs. Vet. Clin. North Am. - Small Anim. Pract. 2020, 50, 419–430, doi:10.1016/j.cvsm.2019.11.003.

6. Riggs, J.; Liu, N.C.; Sutton, D.R.; Sargan, D.; Ladlow, J.F. Validation of exercise testing and laryngeal auscultation for grading brachycephalic obstructive airway syndrome in pugs, French bulldogs, and English bulldogs by using whole-body barometric plethysmography. Vet. Surg. 2019, 48, 488–496, doi:10.1111/vsu.13159.

7. Koch, D.A.; Arnold, S.; Hubler, M.; Montavon, P.M. Brachycephalic syndrome in dogs. Compend. Contin. Educ. Pract. Vet. 2003, 25, 48–55.

8. Lorenzi, D. De; Bertoncello, D.; Drigo, M. Bronchial abnormalities found in a consecutive series of 40 brachycephalic dogs. October 2008, 835–840.

9. Wardlaw, J.L.; Givaruangsawat, S. Brachycephalic airway obstructive syndrome in dogs: 90 cases (1991–2008). J. Am. Vet. Med. Assoc. 2010, 237, 2008–2011.

10. Torrez, C. V.; Hunt, G.B. Results of surgical correction of abnormalities associated with brachycephalic airway obstruction syndrome in dogs in Australia. J. Small Anim. Pract. 2006, 47, 150–154, doi:10.1111/j.1748-5827.2006.00059.x.

11. Crosse, K.R.; Bray, J.P.; Orbell, G.M.B.; Preston, C.A. Histological evaluation of the soft palate in dogs affected by brachycephalic obstructive airway syndrome. N. Z. Vet. J. 2015, 63, 319–325.

12. Poncet, C.M.; Dupre, G.P.; Freiche, V.G.; Estrada, M.M.; Poubanne, Y.A.; Bouvy, B.M. Prevalence of gastrointestinal tract lesions in 73 brachycephalic dogs with upper respiratory syndrome. J. Small Anim. Pract. 2005, 46, 273–279, doi:10.1111/j.1748-5827.2005.tb00320.x.

13. Poncet, C.M.; Dupre, G.P.; Freiche, V.G.; Bouvy, B.M. Long-term results of upper respiratory syndrome surgery and gastrointestinal tract medical treatment in 51 brachycephalic dogs. J. Small Anim. Pract.2006, 47, 137–142, doi:10.1111/j.1748-5827.2006.00057.x.

14. Hendricks, J.C. Brachycephalic airway syndrome. In Textbook of respiratory disease in dogs and cats; Elsevier, 2004; pp. 310–318.

15. Packer, R.; O’Neill, D. Health and welfare of brachycephalic (flat-faced) companion animals: a complete guide for veterinary and animal professionals; CRC Press, 2021; ISBN 0429553811.

16. Liu, N.C.; Sargan, D.R.; Adams, V.J.; Ladlow, J.F. Characterisation of brachycephalic obstructive airway syndrome in French bulldogs using whole-body barometric plethysmography. PLoS One 2015, 10, doi:10.1371/journal.pone.0130741.
臨床診斷

運動測試是診斷犬隻BOAS最常見的方法。運動測試又分為「3分鐘跑步測試」和「5分鐘走路測試」。研究指出，法國鬥牛犬、英國鬥牛犬和巴哥犬三種犬種進行「3分鐘跑步測試」和「5分鐘走路測試」後，「3分鐘跑步測試」診斷BOAS的「敏感度」較「5分鐘走路測試」高 [1]。除了運動測試外，喉頭聽診預測「喉塌陷」高達100%特異性。因此建議評估法國鬥牛犬、英國鬥牛犬和巴哥犬BOAS嚴重程度時，同時進行「3分鐘跑步測試」並搭配「喉頭聽診」。

此外，芬蘭的研究團隊指出，「1000公尺走路測試」（距離固定）和「6分鐘走路測試」（時間固定）來評估英國鬥牛犬的BOAS【2】。結果顯示，患有BOAS的犬隻走路距離顯著短於未患病的犬隻，且走路速度也更慢。

全體體積描述器（Whole-body barometric plethysmography , WBBP）檢測吸氣和呼氣過程中呼吸機內的壓力變化，並使用波以耳定律分析氣體體積。WBBP已被廣泛使用評估動物中的各種呼吸狀況 [3-13]。WBBP已被用於檢測氣道阻塞 [14, 3-4]、氣道反應性 [4, 15]、貓的下呼吸道疾病 [13, 16] 和短顱犬阻塞性呼吸道症候群（BOAS）[1, 18]。WBBP搭配專屬程式即可量化BOAS的嚴重程度 [19]，嚴重程度評分從0（無BOAS）到100%（嚴重BOAS）。這種非侵入性切客觀的呼吸功能測試，可以進一步研究BOAS的風險因子、手術效果評估 [20-22]。

1. Riggs, J.; Liu, N.C.; Sutton, D.R.; Sargan, D.; Ladlow, J.F. Validation of exercise testing and laryngeal auscultation for grading brachycephalic obstructive airway syndrome in pugs, French bulldogs, and English bulldogs by using whole-body barometric plethysmography. Vet. Surg. 2019, 48, 488–496, doi:10.1111/vsu.13159.

2. Lilja-Maula, L.; Lappalainen, A.K.; Hyytiäinen, H.K.; Kuusela, E.; Kaimio, M.; Schildt, K.; Mölsä, S.; Morelius, M.; Rajamäki, M.M. Comparison of submaximal exercise test results and severity of brachycephalic obstructive airway syndrome in English bulldogs. Vet. J. 2017, 219, 22–26, doi:10.1016/j.tvjl.2016.11.019.

3. Hamelmann, E.; Schwarze, J.; Takeda, K.; Oshiba, A.; Larsen, G.L.; Irvin, C.G.; Gelfand, E.W. Noninvasive measurement of airway responsiveness in allergic mice using barometric plethysmography. Am. J. Respir. Crit. Care Med. 1997, 156, 766–775.

4. Hoffman, A.M.; Dhupa, N.; Cimetti, L. Airway reactivity measured by barometric whole-body plethysmography in healthy cats. Am. J. Vet. Res. 1999, 60, 1487–1492.

5. Halloy, D.J.; Kirschvink, N.A.; Vincke, G.L.; Hamoir, J.N.; Delvaux, F.H.; Gustin, P.G. Whole body barometric plethysmography: a screening method to investigate airway reactivity and acute lung injuries in freely moving pigs. Vet. J. 2004, 168, 276–284.

6. Kirschvink, N.; Leemans, J.; Delvaux, F.; Snaps, F.; Marlin, D.; Sparkes, A.; Clercx, C.; Gustin, P. Non-invasive assessment of growth, gender and time of day related changes of respiratory pattern in healthy cats by use of barometric whole body plethysmography. Vet. J. 2006, 172, 446–454.

7. Talavera, J.; Kirschvink, N.; Schuller, S.; Le Garrérès, A.; Gustin, P.; Detilleux, J.; Clercx, C. Evaluation of respiratory function by barometric whole-body plethysmography in healthy dogs. Vet. J. 2006, 172, 67–77.

8. Hirt, R.A.; Vondrakova, K.; de Arespacochaga, A.G.; Gütl, A.; van den Hoven, R. Effects of cadmium chloride inhalation on airflow limitation to histamine, carbachol and adenosine 5′-monophosphate assessed by barometric whole body plethysmography in healthy dogs. Vet. J. 2007, 173, 62–72.

9. Hirt, R.A.; Leinker, S.; Mosing, M.; Wiederstein, I. Comparison of barometric whole body plethysmography and its derived parameter enhanced pause (PENH) with conventional respiratory mechanics in healthy Beagle dogs. Vet. J. 2008, 176, 232–239.

10. Kirschvink, N.; Leemans, J.; Delvaux, F.; Snaps, F.; Clercx, C.; Gustin, P. Non-invasive assessment of airway responsiveness in healthy and allergen-sensitised cats by use of barometric whole body plethysmography. Vet. J. 2007, 173, 343–352.

11. Bernaerts, F.; Talavera, J.; Leemans, J.; Hamaide, A.; Claeys, S.; Kirschvink, N.; Clercx, C. Description of original endoscopic findings and respiratory functional assessment using barometric whole-body plethysmography in dogs suffering from brachycephalic airway obstruction syndrome. Vet. J. 2010, 183, 95–102.

12. Manens, J.; Bolognin, M.; Bernaerts, F.; Diez, M.; Kirschvink, N.; Clercx, C. Effects of obesity on lung function and airway reactivity in healthy dogs. Vet. J. 2012, 193, 217–221.

13. Lin, C.-H.; Lee, J.-J.; Liu, C.-H. Functional assessment of expiratory flow pattern in feline lower airway disease. J. Feline Med. Surg. 2014, 16, 616–622.

14. Rozanski, E.A.; Hoffman, A.M. Lung mechanics using plethysmography and spirometry. Textb. Respir. Dis. dogs cats. St Louis Saunders 2004, 175–180.

15. Bergren, D.R. Chronic tobacco smoke exposure increases airway sensitivity to capsaicin in awake guinea pigs. J. Appl. Physiol. 2001, 90, 695–704.

16. Lin, C.; Wu, H.; Lee, J.; Liu, C. Functional phenotype and its correlation with therapeutic response and inflammatory type of bronchoalveolar lavage fluid in feline lower airway disease. J. Vet. Intern. Med.2015, 29, 88–96.

17. Riggs, J.; Liu, N.C.; Sutton, D.R.; Sargan, D.; Ladlow, J.F. Validation of exercise testing and laryngeal auscultation for grading brachycephalic obstructive airway syndrome in pugs, French bulldogs, and English bulldogs by using whole-body barometric plethysmography. Vet. Surg. 2019, 48, 488–496, doi:10.1111/vsu.13159.

18. Liu, N.C.; Sargan, D.R.; Adams, V.J.; Ladlow, J.F. Characterisation of brachycephalic obstructive airway syndrome in French bulldogs using whole-body barometric plethysmography. PLoS One 2015, 10, doi:10.1371/journal.pone.0130741.

19. Liu, N.C.; Adams, V.J.; Kalmar, L.; Ladlow, J.F.; Sargan, D.R. Whole-Body Barometric Plethysmography Characterizes Upper Airway Obstruction in 3 Brachycephalic Breeds of Dogs. J. Vet. Intern. Med. 2016, 30, 853–865, doi:10.1111/jvim.13933.

20. Liu, N.C.; Troconis, E.L.; Kalmar, L.; Price, D.J.; Wright, H.E.; Adams, V.J.; Sargan, D.R.; Ladlow, J.F. Conformational risk factors of brachycephalic obstructive airway syndrome (BOAS) in pugs, French bulldogs, and bulldogs. PLoS One 2017, 12, 1–24, doi:10.1371/journal.pone.0181928.

21. Liu, N.C.; Genain, M.A.; Kalmar, L.; Sargan, D.R.; Ladlow, J.F. Objective effectiveness of and indications for laser-assisted turbinectomy in brachycephalic obstructive airway syndrome. Vet. Surg. 2019, 48, 79–87, doi:10.1111/vsu.13107.

22. Liu, N.C.; Oechtering, G.U.; Adams, V.J.; Kalmar, L.; Sargan, D.R.; Ladlow, J.F. Outcomes and prognostic factors of surgical treatments for brachycephalic obstructive airway syndrome in 3 breeds. Vet. Surg.2017, 46, 271–280, doi:10.1111/vsu.12608.
治療及預後