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Transient Horner’s syndrome and ipsilateral facial hypopigmentation in an acromelanistic cat 一只重点色猫短暂性霍纳氏综合征和单侧面部色素减退
作者：Andrea T.H. Lam and Lesli N. Kibler
翻译：王羽迪 Horner’s syndrome (HS) occurs when the sympathetic nerve pathway is disrupted. This case report describes a cat with acromelanism that developed unilateral facial hypopigmentation concurrently with HS after an oesophagostomy tube was placed. Both the hypopigmentation and HS resolved completely following removal of the oesophagostomy tube. 摘要-当交感神经通路被破坏时，霍纳氏综合征(HS)就会发生。本病例报告描述了一只重点色猫，在放置食道饲管后发生了单侧面部色素减退和HS。在移除食道饲管后，色素减退和HS均完全恢复。 Horner’s syndrome (HS) is a common condition seen in animals, typically caused by a unilateral disruption to the sympathetic nerve pathway. The central neuron originates from the hypothalamus and descends through the brainstem and spinal cord, synapsing with preganglionic cell bodies at spinal cord segments C8 to T7. Upon exiting the spinal cord, the preganglionic axons ascend through the thoracic and cervical regions adjacent to the vagosympathetic trunk and synapse with postganglionic axons in the cranial cervical ganglion, deep to the tympanic bulla.Postganglionic fibres form a nerve plexus around the internal carotid artery, into the middle ear, through the internal carotid foramen, and converge with the ophthalmic branch of the trigeminal nerve. These sympathetic fibres innervate smooth muscles in the periorbital region and palpebrae. Clinical signs occur as a consequence of sympathetic innervation loss to the eye and include: miosis secondary to incomplete dilation of the affected pupil, ptosis, enophthalmos, protrusion of the third eyelid, and an increase in surface temperature of the face as a result of local peripheral vasodilation. HS in cats has been extensively documented as a sequela to inflammatory and noninflammatory middle ear disease, neoplasia, retrobulbar abnormalities, cervical trauma or vascular disease, or it can be idiopathic. 霍纳氏综合征(HS)是动物的一种常见疾病，通常由单侧交感神经通路中断引起。中枢神经元起源于下丘脑，通过脑干和脊髓，向下至脊髓C8至T7段的节前胞体突触。离开脊髓后，节前轴突通过毗邻迷走交感神经干和颅颈神经节中的节后轴突的胸椎和颈部区域上升，深入到鼓室大疱。节后纤维在颈内动脉周围形成神经丛，通过颈内孔进入中耳，并与三叉神经的眼支汇合。这些交感神经纤维支配眶周区域和眼睑的平滑肌。眼部交感神经缺失的临床症状包括:瞳孔不完全扩张引起的瞳孔缩小、上眼睑下垂、眼球凹陷、第三眼睑突出，以及局部外周血管舒张导致面部表面温度升高。
A 14-year-old castrated male sealpoint Siamese-cross weighing 3.9 kg was presented to Tufts Veterinary Emergency Treatment & Specialties for evaluation of progressive, unilateral left-sided hypopigmentation of the face (Figure 1) of three months duration. The cat had been diagnosed previously with HS after having oesophagostomy tube placement to manage hyporexia associated with chronic kidney disease. On physical examination, the oesophagostomy tube placed on the left lateral cervical region was intact with no visible or palpable indicators of inflammation or infection. There was marked miosis of the left pupil, mild left-sided ptosis and protrusion of the nictitating membrane. Dermatological examination showed diffuse, patchy, hypopigmentation of the facial hairs on the left muzzle with scant peripheral hypopigmentation extending to the periocular region, ipsilateral to the oesophagostomy tube. The skin was visually unremarkable in the facial region. Acetate tape cytological findings of the affected area did not show evidence of superficial infection. Trichoscopy of affected hairs revealed a lower density of melanin granules in the cortex when compared to hairs sampled from the nonaffected side of the face. The patchy, left-sided hypopigmentation remained unchanged until incidentally, three months later, the feeding tube was dislodged. A new oesophagostomy tube was placed on the right side and no signs of HS developed after this second feeding tube placement. Over the following four to eight weeks, both the HS and patchy facial hypopigmentation resolved completely (Figure 2). 一只重3.9公斤的14岁已去势雄性重点色杂交暹罗猫就诊于塔夫茨兽医急诊和专科医院，以评估三个月的进行性单侧左侧面部色素减退（图1）。这只猫进行了食道饲管放置以管理慢性肾病有关的厌食，之后被诊断为霍纳氏综合征。进行体格检查，食管饲管置于左侧颈外侧，未见明显触诊炎症或感染症状。左侧瞳孔明显缩小，左侧轻度上眼睑下垂，瞬膜突出。皮肤学检查显示左侧口周面部毛发呈弥漫性、斑片状、色素减退，周围少量色素减退延伸至眼周区，与食管饲管同侧。面部区域的皮肤在视觉上不明显。醋酸胶带细胞学结果的显示没有证据证明浅表感染。患病毛发镜检显示，与未患病的一侧面部的毛发相比，皮质中的黑色素颗粒密度较低。在3个月后，食道饲管拆除之前，左侧斑片状色素减退一直没有改变。在右侧放置了一根新的食管饲管，在第二次放置食道饲管后没有出现霍纳氏综合征的症状。在接下来的4到8周内，HS和斑片状面部色素减退均完全恢复(图2)。
Figure 1. Patch of hypopigmenation on the left muzzle of a sealpoint Siamese-cross with scant peripheral hypopigmentation extending to the left periocular region, ipsilateral to oesophagostomy tube placement site. Note the clinical signs associated with Horner’s syndrome: enophthalmos, anisocoria, miosis and mild ptosis. 图1.一只重点色杂交暹罗猫左侧口周斑片状色素减退，周围少量色素减退延伸至左眼周区域，食管饲管放置在同侧。 注意与霍纳氏综合征相关的临床症状:眼球凹陷、瞳孔不小不等、瞳孔缩小和轻度上眼睑下垂。
Figure 2. Patchy facial hypopigmentation in a sealpoint Siamesecross has resolved completely, 57 days after the oesophagostomy tube was removed. 图2.在拆除食道饲管57天后，重点色杂交暹罗猫的面部色素减退已完全恢复。
In this case, the distinctive unilateral facial hypopigmentation was suspected to be secondary to HS, and likely a sequela of the patient’s acromelanistic phenotype.Acromelanism is characterised by a light-coloured hair coat punctuated by darker coloured hairs on the extremities (“points”). Thermosensitive tyrosinase more actively converts melanin precursors into melanin at lower body temperatures, resulting in the darker coloured hairs on the pinnae, muzzle, paws and tail. Higher body temperatures result in lower melanin production, thereby resulting in a lighter coloured trunk. This is common in breeds such as Siamese, Birman, ragdoll and Himalayan. A previous case report described similar ipsilateral facial hypopigmentation in a sealpoint Siamese cat with Horner’s syndrome secondary to metastatic adenocarcinoma of the prescapular lymph node. Unfortunately, that cat was euthanised and without follow-up. In the case highlighted in this report, disruption of sympathetic innervation to the face and resultant peripheral vasodilation in the facial skin was thought to cause an increase in the surface temperature on the affected side leading to decreased tyrosinase activity and ipsilateral hypopigmentation. Once the oesophagostomy tube was dislodged, disruption to sympathetic innervation of the face resolved, thereby normalising the surface skin temperature and tyrosinase function. To the best of the authors’ knowledge, this is the first report of transient unilateral facial hypopigmentation, likely due to HS, in a cat with acromelanism. 在本例中，独特的单侧面部色素减退怀疑是继发于HS，可能是患猫肢端黑化症表型的后遗症。肢端黑化的特征是一种浅色的被毛，四肢有深色的毛发(“点”)。在体温较低的情况下，热敏酪氨酸酶会更积极地将黑色素前体转化为黑色素，导致耳廓、口周、爪部和尾部有深色毛发。体温升高会导致黑色素减少，从而导致躯干颜色变浅。这在暹罗猫、伯曼猫、布偶猫和喜玛拉雅猫中很常见。一个以前的病例报告描述了一只重点色暹罗猫类似的同侧面部色素减退，患猫的霍纳综合征继发于囊前淋巴结转移腺癌。不幸的是，这只猫被实施了安乐死，没有进行后续回访。在本报告中强调的病例中，面部交感神经支配的中断和面部皮肤周围血管舒张被认为导致患侧表面温度升高，导致酪氨酸酶活性降低和同侧色素减退。一旦食管饲管被拆除，对面部交感神经的破坏就会得到解决，从而使表面皮肤温度和酪氨酸酶功能恢复正常。据作者所知，这是第一例发生在患有肢端黑化症的猫身上的短暂性单侧面部色素减退的报告，可能是由于HS引起的。
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发表于 2022-2-12 22:17:42
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