Afemaleinfantwasdeliveredviacesareansectionat39weeks’gestationtoa40-year-oldmother.Pregnancywasnotablefornormalfetalmovementandamnioticfluidindices.Apgarscoreswere7and8at1and5minutes.Shortlyafterbirth,theinfantdevelopedrespiratorydistressandapneathatresolvedwithrepositioningofherneckandtrunk.Generalexaminationwasremarkableforseveremicrognathia,higharchedpalate,bitemporalwasting,andbilateraltalipesvarus(clubfoot)contractures.Neurologicexaminationshowedintactmentalstatus,facialdiplegia,axialhypotoniawithverticalsuspension,normalrestingtone(kneesandelbowswereflexedwhensupine),normalstrength(i.e.,antigravitythroughoutherextremities),andnormalinfantileanddeeptendonreflexes.Shewastransferredtoourneonatalintensivecareunitforevaluationofsurgicaloptionstocorrecthermicrognathia.
一位40岁女性孕39周剖宫产分娩一女婴。孕期胎动及羊水指数均正常。Apgar评分1分钟7分，5分钟8分。产后婴儿很快出现呼吸窘迫和呼吸暂停，改变颈部及躯干位置后症状缓解。一般检查见严重的小颌畸形、高弓腭、双颞部萎陷、双侧畸形挛缩内翻足。神经系统查体：精神状态完好，双侧面瘫，竖起后躯干肌张力低，静息状态下肌张力正常（仰卧时膝关节和肘关节屈曲），肌力正常（四肢均可对抗重力），新生儿反射和深反射正常。婴儿转入我们新生儿ICU评估纠正小颌畸形手术选项。
Questionsforconsideration
1.Whatisthedifferentialdiagnosisofneonatalhypotonia?
2.Howdoherphysicalexaminationfindingsnarrowthedifferentialdiagnosis?
思考问题
1.新生儿肌张力低下的鉴别诊断是什么？
2.婴儿体格检查结果是怎样缩小鉴别诊断的？
SECTION2第二部分Awiderangeofdisorderspresentwithhypotoniaduringtheneonatalperiod.Importantdetailstoconsiderintheprenatalhistoryincludequalityandquantityoffetalmovementsandpresenceofpolyhydramnios,asthesefactorsmaysuggestintrauterinehypotoniaorcentralnervoussysteminjury.Cesareansectionduetobreechpresentationmayalsoindicatedecreasedorineffectivefetalmovement.1Neonatalhypotoniacanbeduetocentral,peripheral,ormixedcauses(table1).Centralcausesaremost
