CONGENITALHYPOTHYROIDISM5thYearIntern-

AmilaKannangara1Clinicalscenario..Apregnantmotherwithherhusbandcomestoseeyou.Sheisinherthirdtrimester.Bothofthemarelawyers.TheyhaverecentlyheardaboutcongenitalhypothyroidisminTelevisionandwantstodiscusswithyouhowtoknowiftheirunbornchildisaffected.2Howwillyouadvicethem?Content…1.WhatiscongenitalHypothyroidism?2.CausesbehindCH?3.SignsandsymptomsofCH?4.HowtodiagnoseCH?5.IsCHinherited?6.HowtotestforCH?7.TreatmentofCH?3Whatarethecausesforthiscondition?1.Missingormisplacedthyroidgland

5MostbabieswithCHaremissingtheirthyroidglandorhaveathyroidthatdidnotdevelopproperly.

Insomecases,thethyroidglandmaybesmallerthanusualormaynotbelocatedinthecorrectplace.InsomechildrenwithCH,thethyroidglandmayinsteadbeunderthetongueoronthesideoftheneck.2.HereditarycausesChildrenwiththeinheritedtypeofCHdonotmakeenoughthyroidhormoneeventhoughtheirthyroidglandappearsnormalinsizeandshape.3.Maternaliodinedeficiency4.Maternalthyroidconditionandmedications5.

Multiplebirthswhatproblemsoccur?

.Poorfeedingandpoorsuck.Lowactivitylevel.Fewerbowelmovementsorconstipation.Swellingaroundtheeyes.Cool,pale,dryskin.thefontanelthatcloseslate61.Jaundice2.Hypotonia3.Umbilicalhernia4.LargeswollentongueIfleftuntreated

Coarse,swollenfacialfeaturesBreathingproblemsHoarse-soundingcryDelayedmilestones(sitting,crawling,walking,talking)Wide,shorthandsPoorweightgainandgrowthGoiter(enlargedthyroidglandcausingalumpintheneck)AnemiaSlowheartrateFluidbuild-upundertheskin(calledmyxedema)Hearingloss7WhatisthechanceofCHbeinginherited?About80to85%ofthetime,CHiscausedwhenthethyroidglanddoes

notdevelopatall,ismisplaced,oristoosmall.Inabout15%ofcasesofCH,thethyroidglandappearsnormalbuttheamountofthyroidhormonemadeisreduced.

Thesecasesaremorelikelytobeinherited,butnotalways.

MostofthehereditarytypesofCHareinheritedinanautosomalrecessive

manner.Whenbothparentsarecarriers,thereisa25%chanceineachpregnancyforthechildtohaveCH.Thereisa50%chanceforthechildtobeacarrier,justliketheparents.And,thereisa25%chanceforthechildtohavetwoworkinggenes.9IfachildishavinginheritedformofCH,isgenetictestingavailable?

IfageneticdoctorsuspectsaninheritedformofCH,genetictestingmaybeavailabletoattempttodeterminethegenechangesthatcausedtheCH.

DNA

testing,canbedoneonabloodsample.10Canitbetestedduringpregnancy?CHisnotusuallydetectablebeforebirth.Forthosethatmayhaveaninheritedform,genetictestingcanconfirmonlyaportionofthehereditarycases.

11However,prenataltestingisrarelydoneforCHbecausetreatmentissoeffective.IfachildhasahereditaryformofCH,andifthegenechange(s)havebeenfoundinthechild,DNAtestingispossibleduringfuturepregnancies.WhatisthetreatmentforCH?

Medication

…L-thyroxine

…..Thedoctorandendocrinologistwilldecidehowmuchandhowoften.

…..Doctorswillincreasetheamountofmedicationaschildgrows.13*L-thyroxineneedstobetakenona

dailybasisthroughchild’swholelife.

Monitoring

-weight,height,developmentandoverallhealth.

-regularbloodtests-levelofthyroidhormone.

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DevelopmentalEvaluation

-

Ifchildshowdelaysincertainareasoflearningorspeech,extrahelpcanbearranged.WhathappenswhenCHistreated?

Startedsoonafterbirth-usuallyhavenormalgrowthandintelligenceandcanlivetypicalandhealthylives.

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Iftreatmentisnotstarteduntilseveralmonthsafterbirth,delaysorlearningproblemsmayoccur.Thelevelofdelayvariesfromchildtochild.Clinicalscenario..Apregnantmotherwithherhusbandcomestoseeyou.Sheisinherthirdtrimester.Bothofthemarelawyers.TheyhaverecentlyheardaboutcongenitalhypothyroidisminTVandwantstodiscusswithyouhowtoknowiftheirunbornchildisaffected.Howwillyouadvicethem?17InsummaryAnalysisinUnitedStatesshowsaboutoneinevery3000to4000babiesborninthehasCH.IfachildishavingCH,

85%-misplacedormissingthyroidgland.10%-15%-hereditarycauses.NormallyscreeningforCHisperformedafterthechildisb