甲状腺功能减退症(甲减)Hypothyroidism

甲状腺功能减退症(甲减) Hypothyroidism 中山大学附属第一医院内分泌科 肖海鹏 • 甲减的定义 多种原因引起的甲状腺激素合成,分泌或 生物学效应不足所致。以低代谢率，粘多 糖在组织和皮肤堆积为特征，严重者现 为粘液性水肿（Myxedema）及粘液性水肿 性昏迷。 甲减的分类 根据病变部位分类 • 原发性甲减(甲状腺性) • 继发性甲减（垂体性） • 三发性甲减(下丘脑性) • 受体性甲减（外周性） 甲减的分类 据病因分类 • 药物性甲减 • [3]I治疗后甲减 • 手术后甲减 • 特发性甲减 甲减的分型 • 呆小病（克丁病Cretinism） • 幼年型甲减 • 成年型甲减 Figure 15-11. (Left panel) Infant with severe, untreated congenital hypothyroidism diagnosed prior to the advent of newborn screening. (Right panel) Infant with congenital hypothyroidism identified through newborn screening. Note the striking difference in the severity of the clinical features. Figure 15-12. Ten year old female with severe 1° hypothyroidism due to primary myxedema before (A) and after (B) treatment. Presenting complaint was poor growth. Note the dull facies, relative obesity and immature bod proportions prior to treatment. At age 10 years she had not lost a single deciduous tooth. After treatment was initiated (indicated by the arrow in Panel C), she lost 6 teeth in 10 months and had striking catch up growth. Bone age was 5 years at a chronologic age of 10 years. TSH receptor blocking antibodies were negative. 临床表现 一般表现： 疲劳、畏寒怕冷、出汗减少、 皮肤干燥、萎黄虚肿、面容虚 浮、声音嘶哑、毛发稀少干枯 精神神经： 乏力淡漠、少言嗜睡、反应迟钝 心血管症状：心率减慢、心肌病、心包积液 消化症状： 纳差、便秘、腹胀 其他症状： 贫血、性欲减退、月经过多、泌乳 Figure 9-3. (A) The classic torpid facies of severe myxedema in a man. The face appears puffy, and the eyelids are edematous. The skin is thickened and dry. (B) The facies in pituitary myxedema is often characterized by skin of normal thickness, covered by fine wrinkles. Puffiness is usually less than in primary myxedema. The eyelids are often edematous. The palpebral fissure may be narrwowed because of blepharoptosis, due to diminished tone of the sympathetic nervous fibers to Müller's levator palpebral superious muscle and is the opposite of the lid retraction seen in thyrotoxicosis. The modest measurable exophthalmos seen in some patients with myxedema is presumably related to accumulation of the same mucous edema in the orbit as is seen elsewhere. It is not progressive and carries no threat to vision, as in the ophthalmopathy of Graves' disease. The tongue is usually large, occasionally to the point of clumsiness. Sometimes a patient will complain of this problem. Sometimes it is smooth, as in pernicious anemia (of course, pernicious anemia may coexist). Patients do not usually complain of soreness of the tongue, as they may in pernicious anemia. When anemia is marked, the tongue may be pale, but more often it is red, in contrast to the pallid face. 甲状腺功能检查 1、TSH增高，FT4降低 2、131I摄取率降低 3、TPOAb、TgAb阳性 4、TRH兴奋试验 Figure 9-5. Flow-diagram for the biochemical diagnosis of hypothyroidism. 诊 断 Regulation of Thyroid Hormones Figure 4-3. Basic elements in the regulation of thyroid function. TRH is a necessary tonic stimulus to TSH synthesis and release. TRH synthesis is regulated directly by thyroid hormones. T4 is the predominant secretory product of the thyroid gland, with peripheral deiodination of T4 to T3 in the liver and kidney supplying roughly 80% of the circulating T3. Both circulating T3 and T4 directly inhibit TSH synthesis and release independently; T4 via its rapid conversion to T3. SRIH = somatostatin. 鉴别诊断 1、贫血 2、特发性水肿 3、心包积液 4、低T3综合征 5、蝶鞍增大 治 疗 原 则 • 甲状腺激素终生替代 • 支持疗法，补充营养及维生素B • 病因治疗 治疗注意事项 1、小剂量开始，个体化，监测TSH、FT4 2、慎用镇静剂和麻醉剂，注意保暖和防治 感染 3、伴肾上腺皮质功能减退者，先补皮质激 素，以免诱发肾上腺危象 4、亚临床甲减替代治疗指征：高胆固醇 TSH>10mu/L, 甲状腺自身抗体强阳性 粘液水肿性昏迷的治疗 1、补充甲状腺激素 2、保温、供氧、保持呼吸道通畅 3、氢化可的松的应用 4、补液，摄入水不宜过多 5、处理诱因或合并存在的疾病 甲状腺功能减退症(甲减)�Hypothyroidism 甲 减 的 分 类 甲 减 的 分 类 甲 减 的 分 型 临 床 表 现 甲状腺功能检查 Regulation of Thyroid Hormones 鉴 别 诊 断 治 疗 治疗注意事项 粘液水肿性昏迷的治疗