一例腊肠犬慢性单侧外耳炎和中耳炎伴咽鼓管扩张和腭部...

王帆

Patulous Eustachian tube and palatine defect in a Dachshund with chronic unilateral otitis externa and otitis media

一例腊肠犬慢性单侧外耳炎和中耳炎伴咽鼓管扩张和腭部异常

作者：Sandra N. Koch , Sheila M. F. Torres and Betty Kramek

翻译：闫雪燕

Background – Patulous Eustachian tube (pET) is a rare dysfunction of the Eustachian tube described in humans. It is characterized by failure of the ET to close, resulting in unrestricted passage of air, sound and material between the nasopharynx and the middle ear.

Objective – To report a case of pET associated with otitis in a dog.

Animal – A 6-year old-female spayed Dachshund dog.

Methods and materials – Otoscopic  examination, cytological evaluation, culture and susceptibility, computerized tomography (CT), video otoscopic flushing and surgery.

Results – Left ear otoscopic examination revealed erythema, purulent frothy discharge, ceruminous gland hyperplasia, stenosis and a partial tear of the tympanum. Cytological evaluation from the left external canal showed neutrophils, macrophages, rods and cocci. Aerobic culture showed predominantly multidrug-resistant Pseudomonas aeruginosa. The CT findings of the left ear included chronic changes in the external canal, marked lysis of the tympanic bulla and marked dilation of the ET. During video-otoscope flushing, saline drained through the mouth. Bilateral incomplete hypoplasia of the soft palate was noted. Total ear canal ablation and bulla osteotomy with ET dissection were curative. Histopathological findings were compatible with chronic otitis externa (OE) and media.

Conclusion and clinical importance – To the best of the authors’ knowledge, this is the first case of pET described in animals. The ET dysfunction and palatine defect were likely the cause of the otitis in this dog. Clinicians should investigate pET in animals with signs of OE characterized by frothy liquid and food fragments in the ear canal in addition to sneezing after drinking water.

背景-咽鼓管扩张(pET)在人类中是一种罕见的咽鼓管功能障碍。它的特征是咽鼓管不能闭合，导致空气、声音和物质在鼻咽和中耳之间的畅通无阻。

目的-报告一个伴有中耳炎的pET 患犬病例。

动物-一只6岁的已绝育雌性腊肠犬。

方法和材料-耳镜检查、细胞学评估、细菌培养和药敏试验、CT、视频耳镜冲洗和外科。

结果-左耳耳镜检查见皮肤发红、脓性泡沫样分泌物、耵聍腺增生、狭窄和鼓膜部分撕裂。左侧外耳道细胞学检查显示有中性粒细胞、巨噬细胞、杆菌和球菌。需氧培养显示多重耐药铜绿假单胞菌占主导地位。左耳的CT表现为外耳道的慢性改变，鼓泡明显溶解，ET明显扩张。视频耳镜冲洗耳道时，盐水从口腔流出。双侧软腭发育不全。全耳道切除术和鼓泡截骨术及ET剥离术能治愈。组织病理学发现伴随有慢性外耳炎(OE)和中耳炎。

结论和临床意义-据作者所知，这是动物上的第一例pET报告。ET功能障碍和腭部缺陷可能是导致该犬中耳炎的原因。临床医生应调查患有OE症状的动物是否有pET，其特征是除了喝水后打喷嚏外，耳道内还有带泡沫的液体和食物碎片。

Introduction

介绍

The Eustachian tube (ET) is a complex, small, fibrocartilaginous epithelial-lined tube and an important part of the system of contiguous organs including the nose, soft palate, nasopharynx and tympanic cavity. Normally the ET is a closed structure that opens under the control of paratubal muscles during actions such as chewing or swallowing. Its main functions include equalization of air pressure between the middle ear and nasopharynx, protection of the middle ear from nasopharyngeal pathogen-laden secretions and loud sounds, ventilation and drainage of the middle ear.

咽鼓管(ET)是一种小而复杂的纤维软骨上皮内衬管，是鼻、软腭、鼻咽和鼓室等相邻器官系统的重要组成部分。正常情况下，ET是一个封闭的结构，在咀嚼或吞咽等动作时，在咽鼓管旁肌肉的控制下打开。其主要功能包括平衡中耳与鼻咽部之间的气压，保护中耳不受鼻咽部富含致病菌的分泌物和响亮的声音的侵袭，中耳的通气和引流。

Eustachian tube dysfunction (ETD) is a condition in humans where the ET fails to perform at least one of its functions and it does not open or close properly.There are three subtypes of ETD reported in humans: dilatory ET (insufficient or no dilation) which might be the result of dynamic dysfunction or anatomical or functional obstruction; patulous ET (pET) (failure of closure) where the air, sound and material pass unrestricted between the nasopharynx and the middle ear; and baro-challenge-indued ETD, which is associated with changes in altitude/barometric pressure. These dysfunctions are associated with congenital and acquired factors, having multiple reported causes from ET muscle defects to craniofacial abnormalities such as palatine abnormalities. ETDs in humans have been reported to cause pathological changes in the middle ear such as chronic otitis media (OM).

咽鼓管功能障碍(ETD)是一种人类疾病，其表现为咽鼓管至少有一项功能不能正常发挥，不能正常打开或关闭。在人类中有三种ETD亚型:迟缓性ET(不充分或无扩张)，可能是其动力机能障碍或解剖学或功能障碍导致的;扩张性ET (pET)(闭合失败)空气、声音和其他物质在鼻咽和中耳之间无限制地传递;压力改变诱导性ETD，它与海拔/气压的变化有关。这些功能障碍与先天及后天因素有关，有很多的原因造成，从ET肌肉缺陷到颅面异常，如腭部异常。据报道，人类的ETD会引起中耳的病理变化如慢性中耳炎(OM)。

This report describes a dog with chronic unilateral otitis externa (OE) and OM likely caused by pET and a palatine defect suspected to be congenital in origin. Although there have been a few reports in dogs describing OM presumed to be associated with ET abnormalities, to the best of the authors’ knowledge this is the first report of confirmed ETD in a dog.

本报告描述一只慢性单侧外耳炎(OE)和OM患犬可能由pET和腭部异常导致，怀疑是先天性缺陷。虽然有一些关于犬的报告描述了OM可能和ET异常有关，据作者所知，这是关于犬的ETD确诊的第一例。

Case report

案例分析

A 6-year-old female spayed Dachshund dog was presented for evaluation of chronic left OE first noted at six months of age. The dog showed sneezing after drinking, presence of liquid and food in the left ear after drinking and eating, foamy otic material and episodes of head shaking. Over the years, different organisms were isoated from the left ear including Malassezia pachydermatis, Staphylococcus pseudintermedius, Streptococcus bovis and Escherichia coli. Multiple topical and systemic antimicrobials and glucocorticoids were attempted without success.

一只6岁的雌性已绝育腊肠犬因六月龄时首次出现左耳慢性OE就诊。该犬表现为饮水后打喷嚏，在饮水和进食后左耳有液体和食物流出，有泡沫的耳道分泌物和甩头症状。多年来，从左耳分离出不同的微生物，包括厚皮马拉色菌、假中间型葡萄球菌、牛链球菌和大肠杆菌。尝试了多种外部和全身抗生素和糖皮质激素治疗，但均未成功。

At presentation, otoscopic examination of the left ear revealed mild purulent frothy discharge, moderate ceruminous gland hyperplasia, mild to moderate stenosis and partial tear of the tympanic membrane. Samples for cytological evaluation showed many degenerated neutrophils and macrophages, many rods and few cocci bacteria. Aerobic culture yielded numerous multidrug-resistant (MDR) Pseudomonas aeruginosa and scattered E. coli. The right ear was normal and the dog was otherwise healthy. Computed tomography (CT) was performed with the dog in prone position. Pre- and post-contrast axial images (using intravenous iodine medium) were obtained at 0.5 mm slice thickness and 0.3 mm slice interval, and subsequently reconstructed into 2 mm slice thickness by 2 mm slice interval. Left ear CT findings included severe hyperplasia and stenosis of the external canal, marked lysis of the tympanic bulla and marked ET dilation (Figure 1). The CT findings of the right ear and ET were unremarkable. Saline was noted draining through the mouth during video otoscopic flushing. During intubation, bilateral incomplete hypoplasia of the soft palate and a readily visible left ET orifice (4 mm diameter) in the nasopharynx were noted (Figure 2). Due to the chronic OE unresponsive to therapy, severe middle ear disease and abnormal patent ET, total ear canal ablation and bulla osteotomy (TECABO) with partial ET dissection were performed. The ET opening was catheterized via the oral cavity with a 3.5 French catheter (16 inch feeding tube and urethral catheter, Kendall, Covidien Health Care; Indianapolis, IN, USA). Sterile saline was flushed through the catheter and out of the left ear (Figures 3 and 4). An incision was made at the ET orifice and a small portion of the tube lumen was dissected and removed. Tissue aerobic culture from the left ear demonstrated moderate MDR P. aeruginosa. After surgery, the dog received marbofloxacin (Zeniquin, Zoetis Inc.; Kalama-zoo, MI, USA) at 5 mg/kg orally once daily for two weeks. Histopathological findings showed chronic, mild to moderate hyperplastic OE and moderate to marked OM without evidence of foreign body or neoplasia. The dog recovered well without any post-surgical complications and was asymptomatic during the following five years.

报告中，左耳耳镜检查发现轻度化脓性泡沫状分泌物，中度耵聍腺增生，轻度至中度狭窄，鼓膜部分撕裂。细胞学评估显示有许多退行性中性粒细胞和巨噬细胞，许多杆菌和少数球菌。需氧培养产生大量多重耐药(MDR)铜绿假单胞菌和分散的大肠杆菌。右耳正常，其他方面都很健康。犬采用俯卧位，进行CT检查。在0.5 mm层厚和0.3 mm层厚时分别获得造影前和造影后的轴向影像(使用静脉碘介质)，并以2 mm层厚重建为2 mm影像。左耳CT表现为严重的外耳道严重增生和狭窄，鼓泡明显溶解，ET明显扩张(图1)。右耳CT检查和ET未见明显异常。在视频耳镜冲洗耳道时，发现盐水从口腔流出。插管时，注意到双侧软腭发育不全，以及鼻咽部容易看到的左侧ET口(直径4mm)(图2)。由于慢性的外耳炎对治疗无反应和严重的中耳疾病及异常开放的ET，行全耳道消融术及鼓泡截骨术(TECABO)及部分ET剥离术。采用3.5号法式导管，经过口腔打开咽鼓管。无菌盐水经导管冲洗从左耳流出(图3和图4)，在ET口切开，切开一小部分管腔并取出。从中耳取出的组织需氧培养显示有中度MDR铜绿假单胞菌。手术后，犬接受马波沙星，每日一次，5mg/kg，连续两周。组织病理学表现为慢性、轻度至中度增生性OE，中度至重度OM，无异物或肿瘤病变。该犬恢复得很好，没有任何术后并发症，在接下来的五年里也没有任何症状。

Figure1. Computed  tomography  (axial plane)  of  the skull of a Dachshund dog showing marked dilation of the left Eustachian tube (arrow).

图1.腊肠犬头骨的计算机断层扫描（轴向平面），显示左咽鼓管明显扩张（箭头）。

Figure2. Bilateral incomplete hypoplasia of the soft palate (blue arrow points to one of the affected sides) and visible left Eustachian tube orifice (green arrow)  in  a Dachshund with patulous Eustachian tube dysfunction.

图2。一只患扩张性咽鼓管功能障碍的腊肠犬，双侧软腭发育不全（蓝色箭头指向患耳一边）和肉眼可见的左侧咽鼓管开口（绿色箭头）。

Figure3. Catheterization  of  the  left  Eustachian  tube  via  oral  cavity  with a 3.5 French rubber catheter in a Dachshund with patulous Eustachian tube dysfunction.

图3.一只患扩张性咽鼓管功能障碍腊肠犬，经口腔将3.5号法式橡胶导管插入左侧咽鼓管。

Figure4.  Sterile  saline  flushed  through  the  catheter and seen out the left ear in a Dachshund with patulous Eustachian tube dysfunction.

图4. 一只患扩张性咽鼓管功能障碍的腊肠犬，无菌盐水通过导管冲洗，并从左耳流出。

Discussion

讨论

Similar to the condition in humans, the pET in our case allowed the passage of liquid and solid material from the nasopharynx to the external ear canal. By contrast to humans, where more than half of the cases are bilateral, 2 only the left ear was affected in this dog. However, we cannot predict that a single case represents the majority of dogs with this condition. Patulous ET is slightly more prevalent in women (54%) than men. The dog in this report was female; however, the significance of these findings is unknown. The disease in humans can develop from seven to 85 years of age and clinical signs are often present for many years before diagnosis. In a similar way, the dog’s clinical signs were first noted at six months of age but the pET was diagnosed almost six years later.

与人的疾病相似，本例pET中液体和固体物质可以从鼻咽进入外耳道。与人类相比，超过一半的病例是双侧的，此犬只有左耳患病。然而,我们不能从单个病例预测大多数犬是这种情况。扩张性ET在女性(54%)中比男性更高发。报告中的犬是雌性。然而，这些发现的意义尚不明确。人类的这种疾病可以从7岁到85岁间发病，临床症状通常在确诊前已经存在很多年。同样的，该犬的临床症状在六月龄时就被发现了，但在六年后才被确诊。

The most common symptoms reported in humans with ETD are related to pressure disequilibrium including noise autophony, aural fullness sensation, pulsatile tinnitus, crackling or rumbling sounds, habitual sniffing, discomfort and pain. These signs cannot be easily assessed in dogs; however, the intermittent head shaking noted could indicate a response to some of these signs or sensations. Similar to this canine case, OM is also reported in humans with ETD, with 25 to 30% of humans diagnosed with pET also showing middle ear disease.

据报道，人类ETD患者最常见的症状与压力失衡有关，包括噪音自声过强、听觉充盈感、脉动性耳鸣、噼啪声或隆隆声、习惯性吸气、不适和疼痛。这些症状很难在犬上检测到;然而，不断甩头可能是对这些症状或感觉的反应。与此犬类病例相似，据报道，患有ETD的人中也有OM,, 25%-30%被诊断为pET的人也有中耳疾病。

The pathomechanism of pET in humans is multifactorial, complex and poorly understood, and in most cases an underlying cause is not identified. Many congenital or acquired risk factors have been reported in humans with pET including environmental allergy, laryngopharyngeal or gastroesophageal reflux, trigeminal nerve injury, stress, anxiety, weight loss, radiation therapy, pregnancy, hormone replacement therapy, adenotonsillectomy, autoimmune conditions, neuromuscular disease and palate abnormalities. Despite the unilateral occurrence of ETD, the authors speculate that a congenital bilateral incomplete hypoplasia of the soft palate predisposed this dog to develop pET. The tensor and levator palatine muscles are very important in the ET opening and closing mechanisms. Therefore, an abnormal palate can result in defective function of these muscles. Moreover, there is a high incidence of middle ear effusions in children with congenital cleft palates, which is thought to be caused by ETD as a result of the abnormal palate.

pET在人的病理机制是多因素的、复杂的、了解甚少的，而且在大多数情况下，没有确切病因。有报道的pET患者存在许多先天或后天的风险因素，包括环境过敏、咽喉部或胃食管反流、三叉神经损伤、压力、焦虑、体重减轻、放疗、妊娠、激素替代治疗、腺扁桃体切除术、自身免疫性疾病、神经肌肉疾病和颚部异常。尽管ETD是单侧发生的，但作者推测，先天性双侧软腭发育不全使这只犬更容易发展成pET。颚张肌和提上睑肌在ET的开闭机制中起着非常重要的作用。因此，异常的颚部会导致这些肌肉功能的缺陷。此外，先天性腭裂患儿中耳积液的发生率很高，这被认为是由于腭裂导致的ETD。

The palatine defect in this dog allowed easy access to the ET orifice, which is known to hide behind the soft palate, allowing food and liquid to come out of the ear through the pET, resulting in the development of otitis. Very little information regarding middle ear disease associated with palate abnormalities has been published in animals. A retrospective study reported six dogs with hypoplasia of the soft palate and abnormal radio-graphic changes in the tympanic bullae. A study in Cavalier King Charles spaniels showed a significant association between bilateral OM with effusion and increased soft palate thickness and decreased nasopharyngeal dimension. In addition, unilateral and bilateral OM has been reported in five cats with soft palate defects.

这只犬的腭部缺陷让食物和液体通过隐藏在软腭后面的ET口，从宠物的耳朵流出，导致了中耳炎的发展。很少有关于动物的中耳疾病与颚部异常相关的文章发表。一项回顾性研究报告了6只患犬的软腭发育不全和鼓泡异常影像学改变。一项对查理士王小猎犬的研究表明，双侧OM与积液、软腭厚度增加和鼻咽尺寸减小存在显著的相关性。此外，在5只患有软腭缺陷的猫中报告了单侧和双侧OM。

The diagnosis of pET in humans usually is based on symptoms and evidence on otoscopy or tympanometry. Other diagnostic procedures include pure tone audiometry, nasopharyngoscopy, CT and magnetic resonance imaging. A single diagnostic method has not been shown to provide a complete ET assessment. Tympanometry is not easily performed in dogs and it was not attempted because the dog presented with a ruptured tympanum. In this dog, CT with contrast was sufficient to identify the pET, as demonstrated previously in mesaticephalic canine cadavers.

人类pET的诊断通常基于临床症状耳镜检查或鼓室导抗测试。其他诊断程序包括纯音试听、鼻咽镜检查、CT和磁共振成像。单一的诊断方法尚未被证明能提供完整的ET评估。对犬进行鼓室测定并不容易，因为犬的鼓膜破裂，所以没有人尝试。在这只犬中，增强CT中足以确诊PET，正如先前在犬尸检中所证明的。

Numerous treatments for pET have been reported in humans with insufficient evidence to recommend any particular intervention. They include myringotomy, mucous thickening agents, topical irritants to induce mucosal oedema or thickening, topical estrogen drops, peritubal injections of various materials including paraffin, gel foam and glycerin, electrocauterization, ligation of the pharyngeal orifice, ablation of the ET orifice or lumen and removal of the tubal cartilage. Due to limited knowledge of the best treatment for pET and the chronic and severe involvement of the middle ear and ET, TECABO and ET partial ablation were elected in this case and shown to be successful.

关于人PET治疗有许多报告，但没有足够的证据，来推荐任何特定的治疗方式。它们包括鼓膜切开术、黏液增厚剂、引起黏膜水肿或增厚的外用刺激物、外用雌激素滴剂、咽鼓管旁注射各种物质，包括石蜡、泡沫凝胶和甘油、电烧灼、咽部开口结扎、ET开口或管腔的消融和咽鼓管软骨切除。由于对pET最佳治疗方法的了解有限，以及慢性和越来越严重的中耳炎和ET，本案例中选择了TECABO和ET部分融，并被证明此方案是成功的。

Dogs with early onset of ear disease characterized by the presence of liquid or solids in the external ear canal should have palate abnormalities and ETD investigated. A CT scan with contrast should be considered for diagnosis in those cases. Future studies are needed to better understand ETD in dogs and to identify ideal treatment modalities for this condition.

早期发现以外耳道中存在液体或固体为特征的耳病患犬应该检查是否有颚部异常和ETD。在这些病例中，应考虑进行CT扫描并进行造影诊断。未来的研究需要更好地了解犬的ETD，并确定这种情况的理想治疗方式。