Segmental hypoplasia of the spinal cord and syringomyelia in a calf

ABSTRACT: Congenital malformations are functional and structural changes in organ systems, tissues, or organs that may develop during the embryonic or fetal phase. Spinal cord malformations, such as segmental hypoplasia of the spinal cord (SHSC) and syringomyelia, are rare in bovines. A Girolando calf from Valença, Rio de Janeiro, was admitted to the Veterinary Hospital of Universidade Federal Rural do Rio de Janeiro because of motor incoordination. Clinical evaluation revealed a 5-cm depression area in the spine at the dorsal line of the thoracic region. Neurological examination revealed reduced proprioception, pelvic limb extension with increased nociceptive activity, and reduced anal reflex. In radiographic examination, the body of the T11 vertebra had a trapezoidal wedge shape with ventral hemivertebra, probable agenesis or hypoplasia of the T11-T12 spinous processes, and fusion of the T9-T10 spinous processes. Myelography revealed extradural spinal compression caused by vertebral malformations. Necropsy showed no spinous processes (T11-T12), cranial stenosis in the medullary canal (T11-T13), and 1-3-mm pores in the white matter of the thoracic spinal cord (T8-T11). Microscopy revealed cystic dilatations in the white matter (T9-T11), cystic areas of varying sizes (T8-T9), and moderate reduction in the gray matter around the central canal of the medulla (T11-T13). Here, we reported the clinical and pathological findings of SHSC and syringomyelia in a Girolando calf. The features should be differentiated from other spinal cord syndromes. Congenital malformations are of economic importance, and their etiology and diagnosis are fundamental to disease control and progenitor-selection programs.

摘要：先天性畸形（Congenital malformations）指在胚胎或胎儿发育阶段形成的器官系统、组织或器官的功能与结构异常。脊髓畸形（spinal cord malformations）包括脊髓节段性发育不全（segmental hypoplasia of the spinal cord, SHSC）与脊髓空洞症（syringomyelia），在牛中较为罕见。来自里约热内卢州瓦伦萨的一头吉罗兰多犊牛因运动失调，被送往里约热内卢联邦农村大学（Universidade Federal Rural do Rio de Janeiro）兽医院就诊。临床检查显示，其胸椎段背侧线对应的脊柱存在一处5厘米的凹陷区域。神经学检查结果为：本体感觉减退、后肢伸展伴痛觉反应增强，且肛门反射减弱。放射影像学检查发现，第11胸椎椎体呈梯形楔形并伴腹侧半椎体，T11-T12棘突大概率存在发育不全或未发育，T9-T10棘突发生融合。脊髓造影检查显示，脊柱畸形引发了硬膜外脊髓压迫。剖检结果表明，T11-T12段无棘突，T11-T13段髓管颅侧狭窄，T8-T11段胸髓白质存在1-3毫米的孔洞。显微镜检查显示，T9-T11段白质存在囊性扩张，T8-T9段存在大小不一的囊性区域，T11-T13段髓质中央管周围的灰质出现中度减少。本研究报告了一例吉罗兰多犊牛的SHSC与脊髓空洞症的临床及病理表现，该病症的特征需与其他脊髓综合征进行鉴别诊断。先天性畸形具有经济重要性，其病因学与诊断方法是疾病防控及种畜选育计划的核心基础。