内分泌内科-甲减

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，严重者表现为粘液性水肿（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3I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,Figure15-11.(Leftpanel)Infantwithsevere,untreatedcongenitalhypothyroidismdiagnosedpriortotheadventofnewbornscreening.(Rightpanel)Infantwithcongenitalhypothyroidismidentifiedthroughnewbornscreening.Notethestrikingdifferenceintheseverityoftheclinicalfeatures.,Figure15-12.Tenyearoldfemalewithsevere1hypothyroidismduetoprimarymyxedemabefore(A)andafter(B)treatment.Presentingcomplaintwaspoorgrowth.Notethedullfacies,relativeobesityandimmaturebodproportionspriortotreatment.Atage10yearsshehadnotlostasingledeciduoustooth.Aftertreatmentwasinitiated(indicatedbythearrowinPanelC),shelost6teethin10monthsandhadstrikingcatchupgrowth.Boneagewas5yearsatachronologicageof10years.TSHreceptorblockingantibodieswerenegative.,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,Figure9-3.(A)Theclassictorpidfaciesofseveremyxedemainaman.Thefaceappearspuffy,andtheeyelidsareedematous.Theskinisthickenedanddry.(B)Thefaciesinpituitarymyxedemaisoftencharacterizedbyskinofnormalthickness,coveredbyfinewrinkles.Puffinessisusuallylessthaninprimarymyxedema.Theeyelidsareoftenedematous.Thepalpebralfissuremaybenarrwowedbecauseofblepharoptosis,duetodiminishedtoneofthesympatheticnervousfiberstoMllerslevatorpalpebralsuperiousmuscleandistheoppositeofthelidretractionseeninthyrotoxicosis.Themodestmeasurableexophthalmosseeninsomepatientswithmyxedemaispresumablyrelatedtoaccumulationofthesamemucousedemaintheorbitasisseenelsewhere.Itisnotprogressiveandcarriesnothreattovision,asintheophthalmopathyofGravesdisease.Thetongueisusuallylarge,occasionallytothepointofclumsiness.Sometimesapatientwillcomplainofthisproblem.Sometimesitissmooth,asinperniciousanemia(ofcourse,perniciousanemiamaycoexist).Patientsdonotusuallycomplainofsorenessofthetongue,astheymayinperniciousanemia.Whenanemiaismarked,thetonguemaybepale,butmoreoftenitisred,incontrasttothepallidface.,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,Figure9-5.Flow-diagramforthebiochemicaldiagnosisofhypothyroidism.,诊断,RegulationofThyroidHormones,Figure4-3.Basicelementsintheregulationofthyroidfunction.TRHisanecessarytonicstimulustoTSHsynthesisandrelease.TRHsynthesisisregulateddirectlybythyroidhormones.T4isthepredominantsecretoryproductofthethyroidgland,withperipheraldeiodinationofT4toT3intheliverandkidneysupplyingroughly80%ofthecirculatingT3.BothcirculatingT3andT4directlyinhibitTSHsynthesisandreleaseindependently;T4viaitsrapidconversiontoT3.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、FT42、慎用镇静剂和麻醉剂，注