|
Canine otitis externa — Treatment and complications 犬外耳炎--治疗及并发症 Jangi Bajwa 翻译：王帆
Otitis externa is an inflammatory disease of the external ear canal, including the ear pinna. Otitis externa may be acute or chronic (persistent or recurrent otitis lasting for 3 months or longer). Changes that occur in the external ear canal in response to chronic inflammation may include glandular hyperplasia, glandular dilation, epithelial hyperplasia, and hyperkeratosis. These changes usually result in increased cerumen production along the external ear canal, which contributes to increase in local humidity and pH of the external ear canal, thus predisposing the ear to secondary infection. 外耳炎是外耳道的一种炎性疾病，包括耳廓。外耳炎可分为急性或慢性(持续性或复发性耳炎持续3个月或更长时间)。慢性炎症引起的外耳道病变包括腺体增生、腺体扩张、上皮增生和角化过度。这些变化通常导致沿外耳道产生的耳垢增多，这导致外耳道的局部湿度和pH值增加，从而使耳道易继发感染。
The bacteria most commonly isolated from ear canals of dogs affected by otitis are Staphylococcus spp.. Other bacteria commonly associated with otitis include Pseudomonas, Proteus, Enterococcus, Streptococcus, and Corynebacterium. Some bacteria such as Staphylococcus and Pseudomonas may produce biofilm, which can lead to persistence of infection despite adequate therapy, as the biofilm needs to be disrupted for any antimicrobial therapy to be effective in clearing the infection. Malassezia yeast is another common component of otitis externa in dogs. Some dogs appear to develop an allergic response to Malassezia spp., leading to significant discomfort and pruritus. 耳炎患犬的耳道中最常见的细菌是葡萄球菌。其他常见的与耳炎相关的细菌包括假单胞菌、变形杆菌、肠球菌、链球菌和棒状杆菌。一些细菌如葡萄球菌和假单胞菌可能产生生物膜，这可能导致虽然进行了充分的治疗但感染还持续存在，因为任何抗菌治疗都需要破坏生物膜才能有效清除感染。马拉色酵母菌是犬外耳炎的另一常见微生物。有些犬似乎对马拉色菌产生了过敏反应，导致明显的不适和瘙痒。
Acute and uncomplicated otitis externa can often be treated successfully, but chronic or recurrent otitis externa is more challenging. Typically, underlying primary factors as well as predisposing and perpetuating factors are at play, including secondary otic infection. Repeated bouts of inflammation and infection can cause secondary changes in the ear canal that can ultimately lead to further lack of success in treating otitis, and possible end-stage ear disease. Severe glandular changes, fibrosis, stenosis, and calcification along the external ear canal lead to patient discomfort as well as progression of otitis from acute to chronic, and from straightforward to complicated otic disease. These changes are indicative of end-stage ear disease, that can usually be avoided with appropriate therapy for secondary and primary disease early in its progression. Client education and regular follow-up evaluations are key to prevention of end-stage ear disease. 急性和无并发症的外耳炎通常可以成功治疗，但慢性或复发性外耳炎更具挑战。通常情况下，潜在的原发因素以及易感因素和持久因素都在发挥作用，包括耳部继发感染。反复发作的炎症和感染会导致耳道的继发性变化，最终导致进一步治疗耳炎失败，并可能导致晚期耳病。沿外耳道严重的腺体改变、纤维化、狭窄和钙化可导致患病动物不适，并使耳炎由急性发展为慢性，由简单耳病发展为复杂耳病。这些变化是晚期耳病的表现，通常可以通过对早期的继发和原发疾病进行适当的治疗来避免。客户教育和定期复诊是预防晚期耳病的关键。
Clinical diagnosis and etiological factors 临床诊断及病因
Otitis externa is common in dogs, and may be unilateral or bilateral. Evaluation for otitis and its diagnosis is based on ear canal palpation, visual inspection of ears, including otoscopic examination, and cytological analysis of otic contents. 外耳炎常见于犬，可单侧或双侧。耳炎的评估和诊断是基于耳道触诊、视诊(包括耳镜检查)和耳分泌物细胞学检查。
Changes to the ear pinna may include alopecia, excoriation, crusting, erythema, and hyperpigmentation. The external ear canal may exhibit presence of hyperemia, ulceration, ceruminous or suppurative discharge, masses, stenosis, glandular changes, or foreign bodies. Usually more than one abnormal finding is noted within an affected ear. Evaluation of the tympanic membrane forms a key part of the otoscopic evaluation, though it may be difficult to assess the tympanum when otitis externa is present. It is reasonable to leave assessment of the tympanic membrane to a later date, after changes attributed to active otitis have been corrected. 耳廓的变化包括脱毛、抓痕、结痂、红斑和色素沉着。外耳道可出现充血、溃疡、耵聍或脓性分泌物、肿块、狭窄、腺体改变或异物。在患耳内通常有一种以上的异常表现。对鼓膜的评估是耳镜检查的关键部分，但当存在外耳炎时，对鼓膜的评估可能比较困难。在恶化的耳炎引起的变化得到纠正后，在对鼓膜进行评估较为合理。
Cytological evaluation of otic contents is the single most informative diagnostic test that helps with treatment of otitis. Otic cytological evaluations also help monitor response to therapy. Occasionally, bacterial culture sampling from the horizontal ear canal may be used to help determine treatment options and for selection of systemic antibiotic therapy, if indicated. Imaging studies such as radiographs, computed tomography (CT) scan or magnetic resonance imaging (MRI) are not routinely used but can be helpful in cases of chronic otitis, or when otitis media is of concern. 耳分泌物的细胞学检查是帮助治疗耳炎的唯一最有信息的诊断试验。耳部细胞学评估也有助于监测对治疗的效果。偶尔，水平耳道的细菌培养取样可用于帮助确定治疗方案和选择全身抗生素治疗，如果有需要。影像学检查，如x线片、计算机断层扫描(CT)或磁共振成像(MRI)并不常用，但对慢性耳炎或中耳炎有帮助。
It is vital that the clinician evaluate involvement of various primary, predisposing, and perpetuating factors that may be contributing to ear disease while evaluating each individual patient affected by otitis externa. If all or most of these factors are identified, resolution of current otitis and prevention of future otitis episodes are likely. 临床医生在评估外耳炎患病动物时，必须评估可能导致耳病的各种原发因素、易感因素和持久因素。如果能明确所有因素或大部分因素，就有可能解决现有的耳炎，以及预防耳炎再发作。
Primary factors 原发因素 Primary factors are diseases that have a direct effect on the external ear canal and can cause otitis, including otic parasites such as Otodectes cyanotis, hypersensitivity disease [food allergy, atopic dermatitis, contact hypersensitivity (Figure 1)], endocrine disease such as hypothyroidism, otic neoplasia and foreign bodies. Underlying hypersensitivity disease is the most common primary factor leading to otitis in dogs. 原发因素是直接影响外耳道，引起耳炎的疾病,包括耳道寄生虫，如耳螨、过敏性疾病(食物过敏、特应性皮炎、接触性过敏症(图1))、内分泌疾病如甲状腺功能减退、耳道肿瘤和异物。潜在的过敏性疾病是导致犬耳炎最常见的原发因素。
Figure 1. Contact hypersensitivity reaction to topical otic medication during treatment for otitis externa. 图1 外耳炎治疗中外用耳药导致的接触性过敏反应。
Predisposing factors 易感因素 Predisposing factors are factors that alter the local ear canal environment and create an increased risk for development of otitis externa. Ears with excessive hair, stenotic ears, increased cerumen production in the canals, otic masses, frequent ear cleaning, as well as changes in external environmental temperature and humidity can all act as predisposing factors. 易感因素是改变局部耳道环境并增加外耳炎发病风险的因素。毛发过多、耳道狭窄、耳道中耳垢增多、耳部肿物、频繁清洗耳道以及外部环境温度和湿度的变化都是易感因素。
Perpetuating factors 持久因素 Perpetuating factors are factors that do not initiate inflammation but lead to exacerbation of the inflammatory process and maintain ear disease even if the primary factor has been identified and corrected. Bacteria such has Staphylococcus and Pseudomonas, and Malassezia yeast are common perpetuating factors. If infection travels to the tympanic bulla, presence of this infection in the middle ear can also act as a perpetuating factor, leading to recurrent external ear infections. Perpetuating factors are often the main reason for treatment failure in dogs affected by recurrent otitis externa. 持久因素是指不引发炎症，但导致炎症过程恶化并使耳病持续的因素，即使原发因素已被识别和纠正。葡萄球菌、假单胞菌等细菌，以及马拉色菌等酵母菌是常见的持久因素。如果感染传播到鼓泡，中耳的感染也可以是一种持久因素，导致外耳感染复发。持久因素往往是复发性外耳炎犬治疗失败的主要原因。
Treatment of otitis externa 外耳炎治疗 Effective treatment of ear infection includes treatment of infection and inflammatory changes as well as determination of the underlying factors that led to development of otitis in the first place. Topical therapy is the mainstay treatment for otitis externa although systemic use of anti-inflammatory therapy and/or antimicrobial therapy may be indicated for individual patients. Most dogs with otitis, irrespective of its cause, will benefit from anti-inflammatory therapy. Glucocorticoids can be used for a short duration to help with reduction of pain and swelling, thus helping with improved compliance for ear cleaning and medication administration. Glucocorticoids can also help disrupt biofilm formation and prevent development of chronic otic changes. Long courses or dependence on glucocorticoids for management of otic disease is not encouraged, unless it is necessary. Typically, systemic antibiotic therapy for treatment of otitis externa is discouraged. 耳道感染的有效治疗包括治疗感染和炎症变化，以及首先确定导致耳炎发展的潜在因素。外耳炎的主要治疗方法是外部治疗，但个别病例可能需要全身使用抗炎治疗和/或抗菌治疗。大多数耳炎患犬，不论病因如何，抗炎治疗都有效。短时间内使用糖皮质激素可以帮助减轻疼痛和肿胀，从而有助于提高耳道清洁和用药依从性。糖皮质激素还可以帮助破坏生物膜的形成，防止慢性耳部病变的发展。不鼓励长疗程或依赖糖皮质激素治疗耳部疾病，除非必要。一般情况下，不鼓励对外耳炎进行全身抗生素治疗。
While cytological analysis is very helpful with therapeutic decision-making and for monitoring response to therapy, simply treating otic infection may not always lead to a successful outcome. Cleaning ears before topical therapy is critical in helping decrease otic cerumen, thus allowing topical therapy to be effective. Ear cleaning also helps break up the biofilm that may protect bacterial colonies from appropriate antimicrobial therapy. During treatment of otitis externa frequent patient reevaluation, including otic cytology, is encouraged to determine if any changes are needed in treatment. A follow-up evaluation (including palpation, otoscopic examination, and ear canal cytology) to confirm complete resolution is very helpful in ensuring perpetuating or primary factors are not present at the time of completion of therapy. A recurrence of the problem despite documented resolution of otitis indicates need for a thorough review of possible underlying primary disease as well as predisposing and perpetuating factors. 虽然细胞学分析对治疗决策和监测治疗反应非常有帮助，但简单治疗耳部感染可能并不总是导致成功的结果。在外部治疗前清洗耳朵对于帮助减少耳垢至关重要，从而使外部治疗有效。清洁耳道也有助于打破生物膜，这些生物膜可能会保护细菌菌落免受适当的抗菌治疗。在外耳炎治疗期间，鼓励患者经常复查，包括耳部细胞学检查，以确定治疗中是否需要任何改变。随访评估(包括触诊、耳镜检查和耳道细胞学检查)，以确定完全的解决对于确保治疗结束时不存在持久因素或原发因素非常有帮助。尽管结果显示耳炎已治愈，但该问题仍复发，这表明需要彻底审查可能的潜在原发疾病以及易感因素和持久因素。
Otitis and hearing loss 耳炎和听力损失 Dogs may develop hearing loss due to presence of otitis externa. Hearing loss can be classified as conductive, sensorineural, or mixed (combination of conductive and sensorineural). Sensorineural hearing loss may occur when the neurological (cochlea nerve) pathways of the brain are damaged by otitis interna, ototoxic medications, presbycusis, noise, physical trauma, general anesthesia, or infection. Conductive hearing loss may result from otitis related exudates, stenosis, or glandular hyperplasia. When hearing is affected in dogs with otitis externa, cleaning of exudates and debris from the external ear canals results in measurable improvements in hearing. As otitis externa resolves, an improvement in hearing can be noticed in dogs if it was due to changes related to the otitis. Deafness has been reported in dogs due to conductive hearing loss from presence of a mineral oil-based plasticized hydrocarbon gel otic medication in the ear canal. Otic medication was flushed out with improvement in brain stem auditory evoked response (BAER) test values in these patients. 犬因为存在外耳炎可能会出现听力损失。听力损失可分为传导性、感觉神经性或混合性(传导性和感觉神经性的结合)。当大脑的神经(耳蜗神经)通路因内耳炎、耳毒性药物、老年性耳聋、噪音、物理创伤、全身麻醉或感染而受损时，可能会发生感觉神经性听力损失。传导性听力损失可由耳炎相关的分泌物、狭窄或腺体增生引起。当外耳炎患犬听力受损时，清除外耳道分泌物和碎片可以显著改善听力。随着外耳炎的痊愈，如果是由于耳炎导致的改变，则犬的听力会有所改善。有报道称，失聪是由于在耳道中存在可塑性矿物油的凝胶状耳药而导致的传导性听力损失。在这些患病动物中，冲洗耳药，可改善脑干听觉诱发反应(BAER)测试值。
As BAER testing is not usually available in companion animal practice, incidence and degree of hearing loss in dogs affected by otitis externa is difficult to assess. Some pet owners may clue in to symptoms and behavior related to hearing loss affecting their pet, while others may not. A pet-owner-based questionnaire to assess hearing loss in dogs affected by otitis has been developed and may be useful in assessment of hearing loss affecting dogs with chronic otitis with moderate to severe bilateral hearing deficits. 由于在伴侣动物临床中通常没有BAER试验，外耳炎影响犬的听力损失的发生率和程度难以评估。一些宠物主人可能会提示他们的宠物与听力损失有关的症状和行为，而其他人可能不会。一项以宠物主人为基础的调查问卷已发表，可能用于评估双侧中度至重度听力受损的慢性耳炎患犬的听力损失程度。
Otitis media 中耳炎 Otitis media is a common extension of external ear disease and occurs secondary to chronic otitis externa in up to 50% of cases. Chronic suppurative otitis is more commonly associated with middle ear disease than is erythemato-ceruminous otitis. Neurologic abnormalities such as head tilt, nystagmus, ataxia, and cranial nerve deficits may occur with otitis media and otitis interna. The absence of a tympanic membrane is suggestive of otitis media but adequate otoscopic examination can often be difficult to perform when concurrent otitis externa is present. An intact tympanic membrane does not rule out otitis media. Chronic otitis media has been associated with higher grades of hearing loss compared to hearing loss caused by otitis externa. The presence of material in the middle ear can be a perpetuating factor of otitis externa and a cause of therapeutic failure. Referral to a veterinary dermatologist should be considered for all dogs that are presented with signs of recurrent otitis, chronic otitis, or otitis media. Video-otoscopic evaluation and deep ear treatments, with or without myringotomy sampling and medicated infusions, are often helpful in obtaining an accurate diagnosis and treatments that will prevent long-term complications associated with chronic ear disease. Imaging studies should also be considered for patients affected with otitis media. Radiography is of limited benefit and advanced imaging such as CT scan studies are preferred, if available, as they help evaluate for presence of middle ear infection, masses and bony changes to the tympanic bulla. Computed tomography studies are more sensitive and specific compared to radiography in diagnosing middle ear disease. 中耳炎常见于外耳炎的进一步蔓延，高于50%的慢性外耳炎病例会继发中耳炎。与红斑-耵聍耳炎相比，慢性化脓性耳炎更常见于中耳疾病。神经异常，像是歪头、眼球震颤、共济失调和面神经损伤，可发生于中耳炎和内耳炎。鼓膜缺失提示中耳炎，但若伴有外耳炎，则耳镜检查往往难以进行。完整的鼓膜不排除中耳炎的可能。慢性中耳炎导致的听力损失，比外耳炎导致的听力损失严重。中耳内物质的存在可能是外耳炎的持久因素，也是治疗失败的原因之一。所有有复发性耳炎、慢性耳炎或中耳炎症状的犬都应该考虑转诊兽医皮肤科医生。视频耳镜检查和耳部深度治疗，进行或不进行鼓膜切开是采样和药物灌洗，常有助于获得准确的诊断和治疗，从而预防与慢性耳病相关的长期并发症。中耳炎患病动物也应考虑影像学检查。X线检查的效果有限，如果可以，首选高级影响检查，像是CT扫描，因为它们有助于评估中耳感染、肿块和鼓疱的骨质改变。计算机断层扫描在诊断中耳疾病方面比x线检查敏感性和特异性更高。
Prevention of otitis externa and its complications 预防外耳炎及其并发症 Few effective preventive measures exist for otitis externa. Thorough otic examination of all patients presented for a physical examination helps with early detection of mild and early cases of otitis. When dogs are presented with early ear disease, thorough client education and detailed diagnostic work-up, including frequent follow-up examinations, can help prevent development of complications that may lead to chronic otitis, hearing loss, otitis media, and end-stage ear disease. 外耳炎的有效预防措施很少。对所有接受体格检查的患病动物进行全面的耳部检查有助于及早发现轻度和早期的耳炎病例。当犬出现早期耳病时，进行宠主教育和详细的诊断检查，包括经常复诊，可以帮助预防可能导致慢性耳炎、听力损失、中耳炎和晚期耳疾的并发症的发展。
| 
|Archiver|手机版|小黑屋|宠医帮
( 京ICP备2022012070号-2 ) 
发表于 2021-11-4 15:31:05
收藏
转播
分享
淘帖
楼主
