Bilateral Otitis Media Causing Atlanto-Occipital Joint Infection and Neurologic Signs

翻译 By @宠物神经科医生高健

原文网址：

https://todaysveterinarynurse.com/neurology/bilateral-otitis-media-causing-atlanto-occipital-joint-infection-and-neurologic-signs/

Because otitis media and interna can be hard to diagnose without advanced imaging, it is important to take even subtle clinical signs seriously.

由于中耳炎和内耳炎在没有高阶影像学检查的情况下很难诊断，
所以即使是细微的临床症状也要认真对待。

Kathleen graduated in 2007 from the Vet Tech Institute in Pittsburgh, Pennsylvania, with a degree in Veterinary Specialized Technology. In 2015, she received a Bachelor of Science degree from the University of Pittsburgh with a focus on chemistry, biology, and psychology. She has worked for 7 years in general practice and 7 years in specialty practice, primarily neurology. 

Kathleen于2007年毕业于宾夕法尼亚州匹兹堡的兽医技术学院，获得兽医专业技术学位。2015年，她获得了匹兹堡大学(University of Pittsburgh)的化学、生物学和心理学学士学位。她在全科医生临床工作了7年，在专科医生临床工作了7年，主要是神经病学。

On March 26, 2019, “Sam,” a 9-year-old, 4.7-kg, intact male domestic short-haired cat, underwent dental cleaning and extractions of teeth 308, 309, 408, and 409. During the procedure, a mass was found and determined to be a bony prominence from a broken tooth. He was discharged the same day but returned on March 29 due to hiding at home. Dental radiographs showed roots that remained from teeth 308 and 309, so they were extracted. Sam was then hospitalized for medication (clindamycin at 0.27 mg/kg PO q12h) and observation and was discharged on April 5.

2019年3月26日，9岁、体重4.7公斤的未绝育雄性家养短毛猫“Sam”接受了牙齿清洁和拔牙手术，拔牙为308、309、408和409号牙齿。在手术过程中，发现了一个肿物，并确定是一颗断裂牙齿的骨突起。它当天出院，但由于在家里躲藏，于3月29日回到了医院。牙科X光片显示308号和309号牙齿的牙根还在，所以进行了牙根清除手术。随后Sam住院用药治疗(克林霉素0.27 mg/kg PO q12h)并观察，4月5日出院。

Presentation  动物病况

On April 8, Sam was presented to the emergency department of our hospital for difficulty walking and a 2-week history of hiding, pawing at his face, decreased appetite, and “not being himself.” A complete blood count was within normal limits, and blood chemistry showed increased total protein (9.6 g/dL, reference range 6.5 to 8.4 g/dL), decreased albumin (2.3 g/dL, reference 2.8 to 4 g/dL), increased globulin (7.3 g/dL, reference 2 to 5 g/dL), and increased glucose (236 mg/dL, reference 70 to 160 g/dL). 

4月8日，Sam被送到我们医院的急诊科，原因是行走困难，并且有两周的躲藏史，用爪子抓自己的脸，食欲下降，“不能正常表现自己应有的行为”。全血细胞计数在正常范围内，血液生化显示总蛋白升高(9.6 g/dL，参考范围6.5至8.4 g/dL)，白蛋白降低(2.3 g/dL，参考范围2.8至4 g/dL)，球蛋白升高(7.3 g/dL，参考2至5 g/dL)，葡萄糖升高(236 mg/dL，参考70至160 g/dL)。

At the time, the increased total protein and hypoalbuminemia were attributed to dehydration and inappetence.1,2 Hypoalbuminemia can be caused by malnutrition, liver disease, kidney disease, or sepsis.3 Elevated globulin indicates infection or inflammation.3 Hyperglycemia was correlated with the patient’s acute stress.2

当时，总蛋白的增加和低白蛋白血症归因于脱水和食欲不振。1,2 低白蛋白血症可由营养不良、肝脏疾病、肾脏疾病或败血症。3 引起球蛋白升高表明感染或炎症。3 高血糖与病患的急性应激相关。2

During physical examination, Sam was bright, alert, and responsive. He was ambulatory but tetraparetic and knuckling on his forelimbs. The remainder of the examination was unremarkable. Thoracic, cervical, and skull radiographs were taken. The skull radiographs indicated some bony lysis of the cranial mandible, consistent with his recent dental extractions. No other abnormalities were noted. The patient was given fluids (lactated Ringer’s solution at 2.8 mL/kg and a rate of 13 mL/hr) along with clindamycin (22.34 mg/kg IV).

在体检时，Sam 活泼，警觉，反应灵敏。它可以走动，但四肢轻瘫，前肢掌背贴地。检查的其余部分无明显异常。拍摄胸片、颈椎片和颅骨片。颅骨X光片显示颅骨下颌骨有些骨溶解，与它最近拔牙的情况相符。没有发现其他异常。给予它补充液体(乳酸林格氏液，2.8 mL/kg，速率13 mL/hr)和克林霉素(22.34 mg/kg IV)。

The next day, Sam was transferred to the neurology service, where his examination indicated spastic tetraparesis, generalized ataxia, and decreased motor function of all limbs. His postural reactions, which help determine lesion location,4 were abnormal: +0 to 1 (absent to weak) in the thoracic limbs and +1 (weak) in the pelvic limbs. No cranial nerve deficits were noted. Spinal reflexes were normal. Palpation elicited no clear signs of spinal pain. Cranial nerve examination, used to evaluate various nerve pathways to the brain and help with lesion localization,4 revealed no deficits. Because Sam’s cranial nerve examination revealed no abnormalities and because his tetraparesis and abnormal postural reactions were more pronounced in the thoracic than in the pelvic limbs, the neuroanatomic disorder was determined to be localized to the cervical (C1 to C5) spinal cord segment. 

第二天，Sam被转诊到神经科，检查显示它患有痉挛性四肢轻瘫、全身性共济失调和四肢运动功能减退。它的姿势反应有助于确定病变位置，其中有4项异常：前肢+0到1(无到减弱)，后肢+1(减弱)。未发现脑神经缺陷。脊髓反射正常。触诊未发现明显的脊柱疼痛迹象。脑神经检查用于评估通往大脑的各种神经通路并帮助定位病变，4 未发现缺陷。由于Sam的脑神经检查未发现异常，并且由于它的四肢轻瘫和异常姿势反应在前肢比在后肢更明显，因此神经解剖学上的疾病被定位于颈(C1至C5)脊髓节段。

Diagnostics, Results, and Diagnosis 诊断方式，结果和诊断

Magnetic resonance imaging (MRI) of Sam’s brain and cranial cervical region was performed by using contrast (gadolinium at 100 mg/kg IV). He was premedicated with buprenorphine (0.4 mg/kg IV), and anesthesia was induced with midazolam (0.2 mg/kg IV) and propofol (4 mg/kg IV). 

采用造影剂(钆gadolinium剂量为100 mg/kg IV)对Sam的大脑和颅颈区进行磁共振成像(MRI)检查，麻醉前用药为丁丙诺啡buprenorphine(0.4 mg/kg IV)，咪达唑仑midazolam(0.2 mg/kg IV)和丙泊酚propofol(4 mg/kg IV)诱导麻醉。

After induction, a fluid bolus (4.26 mg/kg IV) was given to remedy bradycardia (120 beats/min) and hypotension (76/57 mm Hg, mean 65 mm Hg, measured indirectly). Sam’s heart rate increased to 138 beats/min, but his blood pressure did not respond. Atropine (0.04 mg/kg IV) was then given, after which his blood pressure increased to 88/56 mm Hg (mean 68 mm Hg) and remained stable for 25 minutes. Anesthesia was maintained with isoflurane at 1.5 L/min and oxygen at 1 L/min. When heart rate and blood pressure again decreased, to 133 beats/minute and 65/44 mm Hg (mean 59 mm Hg), respectively, a second dose of atropine was given. Isoflurane was turned down to 1 L/min and 2 doses of hetastarch (hydroxyethyl starch) at 2.1 mL/kg IV were administered 5 minutes apart. Hetastarch causes an increase in plasma volume, which in turn increases and maintains appropriate blood pressure. Sam’s blood pressure increased and stayed in the mid-80s (mm Hg) for systolic and the mid-40s (mm Hg) for diastolic (approximate mean 65 mm Hg). 

诱导后，给予4.26 mg/kg液体团注（译者注：可能是 mL/kg），以纠正心动过缓(120次/分)和低血压(76/57 mm Hg，平均65 mm Hg，间接测量法)。Sam的心率增加到每分钟138次，但它的血压没有反应。给予阿托品(0.04 mg/kg IV)后，病患血压升高至88/56 mm Hg(平均68 mm Hg)，并稳定25分钟。维持1.5 L/min异氟烷麻醉，1L/min供氧。当心率和血压再次下降至133次/分钟和65/44mm Hg(平均59mm Hg)时，给予第二次剂量的阿托品。异氟烷降至1 L/min，并以2.1 mL/kg IV给药2剂羟乙基淀粉，间隔5分钟。羟乙基淀粉引起血浆容量增加，从而使血压升高并维持在适当水平。Sam的血压升高，收缩压保持在80 mmHg左右，舒张压保持在40左右(大约平均65mmHg)。

The MRIs showed hyperintense material in both tympanic bullae, more pronounced in the right but more expansive in the left (FIGURES 1–5). The atlanto-occipital (AO) joint showed increased fluid accumulation, which was causing extradural compression of the caudal brain stem and the spinal cord at C1, tapering over the C2 vertebra. The increased fluid and the stronger peripheral contrast enhancement of the AO joint were consistent with septic arthritis. Bilateral otitis media and interna were diagnosed and deemed the most likely source of the joint infection.

MRI显示两个鼓泡存在（T2WI）高强度信号物质，右侧更明显，左侧更具有扩张性(图1-5)。寰枕关节显示积液增多，导致后侧脑干和C1处脊髓的硬膜外压迫，在C2椎体上方逐渐变细。寰枕关节积液增多和外周显著增强，提示化脓性关节炎。双侧中耳炎和内耳炎被诊断为最可能的关节感染来源。

After the MRI, ultrasonography was performed to better visualize the AO joint. The joint was deemed accessible and was aspirated, with 2 to 3 mL of translucent fluid removed for cytology, culture, and sensitivity. 

MRI后进行超声检查以更好地观察寰枕关节。此关节可以够得到并进行穿刺抽吸，取到了2 - 3ml半透明的液体进行细胞学、培养和药物敏感性检查。

After the aspiration, bilateral myringotomy was performed. An otoscope was used to visualize the eardrum. A 12-mL syringe with a 22-gauge spinal needle attached was then gently guided through the eardrum into the internal ear canal, and 4 mL of saline was flushed into each bulla and aspirated back. The aspirated fluid was placed in a culturette. With the needle remaining in place, the syringe was switched out 4 times to flush out the debris and aspirate it back. With the eardrum pierced, any remaining trapped fluid could drain into the external ear canal.5 Myringotomies are performed to obtain specimens for cytology, culture, and antibiotic sensitivity; they can also immediately relieve pain caused by pressure associated with otitis media and interna.5 

抽吸后行双侧鼓膜切开术。用耳镜观察鼓膜。接有22号脊髓针的12ml注射器通过鼓膜轻轻引导进入内耳道，将4ml生理盐水注入鼓泡内并抽吸回去。将抽吸的液体放入培养器中。针头留在原位，切换了4次注射器，反复冲洗掉碎片并将其抽吸回去。鼓膜穿孔后，任何残留的液体都可能流入外耳道。5 进行鼓膜切开术以获得细胞学、培养和抗生素敏感性的样本；它们还能立即缓解由中耳炎和内耳炎引起的压力升高而引起的疼痛。5

Sam was extubated and recovered with heat support. Lactated Ringer’s solution was restarted at 13 mL/hr. Cefazolin was given at 30 mg/kg IV q8h. Enrofloxacin (15 mg/kg IV), dexamethasone SP (0.15 mg/kg IV), and cefovecin (8.5 mg/kg SQ) were each given 1 time.

（停止麻醉）拔掉Sam的气管插管并保暖恢复。乳酸林格氏液以13mL/小时再次输注。头孢唑林（Cefazolin）给药 30 mg/kg IV q8h。恩诺沙星（Enrofloxacin）(15 mg/kg IV)、地塞米松磷酸钠（dexamethasone SP） (0.15 mg/kg IV)、头孢维星（cefovecin）(8.5 mg/kg SQ)各1次。

 

Sam’s vital signs returned to within normal limits, and his demeanor during the night was unremarkable. After much of the fluid in the AO joint had been aspirated, along with steroid treatment, his condition greatly improved within the next few hours. This improvement was presumed to be because the AO joint was no longer as swollen and no longer compressing the brain stem, thereby relieving his symptoms.

Sam的生命体征恢复到正常范围内，它在夜间的举止也变得很平常了。在抽吸了寰枕关节内的大部分液体后，加上类固醇治疗，它的病情在接下来的几个小时内得到了极大的改善。这种改善被认为是因为寰枕关节不再肿胀，不再压迫脑干，从而造成了病患的症状的减轻。

The cytology of the AO joint indicated that the aspirate was highly cellular, consisting of 97% neutrophils, 2% macrophages, and 1% small lymphocytes. No infectious organisms were seen and no growth occurred on culture, presumably the result of antibiotic treatment before hospitalization. The myringotomy aspirate was not sent out for culture because the treatment for the septic AO joint would also treat otitis media and interna.

寰枕关节的细胞学检查表明，抽吸液是富含细胞的，由97%的中性粒细胞、2%的巨噬细胞和1%的小淋巴细胞组成。未见感染性微生物，培养未出现生长，可能是住院前抗生素治疗的结果。由于化脓性寰枕关节的治疗同时也会治疗中耳炎和内耳炎，因此没有将鼓膜切开术的抽吸液送出进行培养。

Treatment and Outcome 治疗和结果

By the day after surgery, Sam’s condition had improved markedly, and his medications were transitioned from intravenous to oral. He was given pradofloxacin (7.4 mg/kg PO q24h) and gabapentin (10.6 mg/kg PO q12h) to prevent nerve pain that may be associated with the infected AO joint. 

手术后的第二天，Sam的病情明显好转，它的药物治疗也从静脉注射转为口服。给予普拉氟沙星（pradofloxacin）(7.4 mg/kg PO q24h)和加巴喷丁（gabapentin）(10.6 mg/kg PO q12h)预防可能与寰枕关节感染相关的神经疼痛。

Physical examination revealed a small amount of dried blood in the left ear canal and some serous ocular discharge. Neurologically, the patient was ambulatory with marginal ataxia. The rest of the examination was unremarkable. Sam was discharged home the next day. The gabapentin was continued for 1 week, pradofloxacin for 1 month, and cefovecin for 2 months (an injection every 2 weeks).

体检发现左侧耳道有少量干血，眼角有浆液性分泌物。神经学方面，病患可走动，伴有边缘性共济失调。检查的其余方面无明显异常。Sam第二天出院回家了。加巴喷丁（gabapentin）治疗1周，普拉氟沙星（pradofloxacin）治疗1个月，头孢维星（cefovecin）治疗2个月(每2周注射一次)。

At the 6-week recheck, the client reported that Sam was doing well, eating and drinking normally, and back to “his old self.” Physical and neurologic examinations revealed no abnormalities, and no recurrence has been reported.

 6 周后复查，宠主报告说Sam一切正常，饮食正常，恢复了“本性”。体格和神经检查未见异常，无复发报道。

Discussion 讨论

Otitis media and interna are somewhat common in cats. It is hypothesized that if left untreated, otitis externa can progress to otitis media and interna, damaging ear structures over time.5 The exact mechanism of otitis media is unknown, but it is theorized that an infection (such as a respiratory pathogen) ascends through the eustachian tube.5 It is also possible for an infection to build up in the external ear canal and rupture the eardrum, causing infection to travel from the external ear canal to the middle ear.5 If left untreated, otitis media and interna can lead to infection in nearby structures, including the brain.5 Only exceedingly rarely does otitis lead to an AO joint infection. Common clinical signs of otitis media and interna include head shaking, pain on palpation of the ear pinna or canal, and reluctance to open the mouth because of swelling within the bulla affecting the temporomandibular joint.5 Otitis media and interna can affect the sympathetic nerves that travel through the middle ear, such as the facial and trigeminal nerves. When they do, Horner’s syndrome, head tilt, or facial nerve palsy can result.5 Even after a thorough ear examination, otitis media and interna can be difficult to diagnose, especially if the eardrum is intact. A classic clinical sign is purulent mucoid exudate along the floor of the horizontal canal, but it is not necessarily diagnostic nor is radiographic assessment always conclusive.5 Otitis media and interna can be diagnosed with MRI or computed tomography. 

中耳炎和中耳炎在猫身上比较常见。据推测，如果不及时治疗，外耳炎会发展为中耳炎和内耳炎，随着时间的推移会损害耳朵结构。5 中耳炎的确切机制尚不清楚，但理论上认为感染(如呼吸道病原体)通过咽鼓管逆行感染。也有可能在外耳道积聚，使鼓膜破裂，导致感染从外耳道传播到中耳。如果不及时治疗，中耳炎和内耳炎会导致附近结构的感染，包括大脑。中耳炎导致寰枕关节感染的情况极为罕见。中耳炎和内耳炎的常见临床症状包括摇头、耳廓或耳道触诊疼痛、因影响颞下颌关节的鼓泡内肿胀而不愿张开嘴巴。中耳炎和内耳炎可影响穿过中耳的交感神经，如面神经和三叉神经。当影响这些神经时时，就会导致霍纳综合症、头部倾斜或面神经麻痹。即使经过彻底的耳部检查，中耳炎和内耳炎也很难诊断，特别是如果鼓膜是完好无损的时候。一个典型的临床征象是沿水平耳道底有脓性粘液渗出，但这并不一定是诊断性的，影像学检查也不总是有结论性的。中耳炎和内耳炎可通过MRI或计算机断层扫描诊断。

Sam’s infection most likely traveled from the middle ear to the AO joint via the vertebral artery, which runs anterior to the AO joint and enters the foramen magnum (FIGURE 6).5 However, other pathways could have been involved, including the carotid artery and jugular vein.4 Sam’s sympathetic nerves were not affected. His clinical signs were initially assumed to have resulted from a tooth abscess. It was not until Sam became tetraparetic that his diagnosis was investigated further. In retrospect, it was determined that his clinical signs were caused by the otitis. The brain stem compression also contributed to Sam’s clinical signs. This type of compression can lead to tetraparesis, generalized ataxia, abnormal postural reactions, weakness, dizziness, impaired vision, neck pain, weakness in the limbs, and proprioceptive deficits.6

Sam的感染极有可能通过椎动脉从中耳传播到寰枕关节，该椎动脉在寰枕关节前方并进入枕骨大孔(图6) 5。然而，其他途径也可能参与其中，包括颈动脉和颈静脉。Sam的交感神经没有受到影响。它的临床症状最初被认为是由牙齿脓肿引起的。直到Sam逐渐发展为四肢轻瘫，它的诊断才得到进一步的调查。经过回顾，确定它的临床症状是由中耳炎引起的。脑干压迫也导致了Sam的临床症状。这种类型的压迫可导致四肢轻瘫、全身性共济失调、异常姿势反应、虚弱 无力、头晕、视力受损、颈部疼痛、四肢无力和本体感觉缺陷。6

Otitis media and interna can be hard to diagnose without access to advanced imaging such as MRI or computed tomography. Therefore, it is important to take even subtle clinical signs seriously. If an outgoing cat suddenly starts to hide in abnormal places, becomes head shy, or exhibits a darker shade of red on its ears, these signs should be cause for concern. Had Sam’s otitis externa been found and treated sooner, the infection might not have progressed. However, as with Sam, some cats do not show many clinical signs until otitis externa progresses. 

中耳炎和内耳炎在没有MRI或计算机断层扫描等高阶成像技术的情况下很难诊断。因此，即使是细微的临床症状也要重视。如果一只外向的猫突然开始躲在不正常的地方，变得害羞，或者耳朵上出现更深的红色斑块，这些迹象应该引起关注。如果Sam的外耳炎能早点被发现并治疗，感染可能就不会恶化了。然而，和Sam一样，有些猫在外耳炎渐进性发展之前没有表现出很多临床症状。

参考文献 References

1. Gatta A, Verardo A, Bolognesi M. Hypoalbuminemia. Intern Emerg Med. 2012;7 Suppl 3:S193–199. doi: 10.1007/s11739-012-0802-0

2. Jain NC. Essentials of veterinary hematology. 1993 Jan 1. archive.org/details/essentialsofvete0000jain/page/n11/mode/2up?view=theater. Accessed January 2021.

3. Medline Plus. Globulin test. 2020 July 31. medlineplus.gov/lab-tests/globulin-test. Accessed January 2021.

4. Dewey CW, da Costa RC, Ducoté JM. Chapter 5: Neurodiagnostics. In: Dewey CW, da Costa RC, eds. Practical Guide to Canine and Feline Neurology. Hoboken, NJ: Wiley-Blackwell; 2016:61–86. 

5. Gotthelf LN. Diagnosis and treatment of otitis media in dogs and cats. Vet Clin North Am Small Anim Pract. 2004;34(2):469–487. doi:10.1016/j.cvsm.2003.10.007

6. Rubin M. Craniocervical junction disorders. Merck Manual. merckmanuals.com/home/brain,-spinal-cord,-and-nerve-disorders/craniocervical-junction-disorders/craniocervical-junction-disorders. Accessed December 2020.

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