多囊性肾脏病变.ppt

CYSTICKIDNEYS,Cysticdiseaseofthekidneysinchildhoodisaconfusingandcomplicatedsubject.Alsothecomplexandoftencontradictorynomenclatureusedtodescribecystickidneysisnotanaidtounderstandingthesubject.Thissectionaimstoprovidethesonographerwithasimpleapproachtocystickidneysinchildren.,Multicystickidneyormulticysticdysplastickidneythisreferstomanycystsinonekidneyoftencontainingsomedysplasticelements.Notallmulticystickidneysaredysplastic.Theconditionisstillconsideredtobenon-hereditary.Ifthemulticystickidneyisunilateral,theotherkidneymaybenormal,hydronephroticordysplastic.Ifbilateral,itisincompatiblewithlife,andinfantsdiesoonafterbirthwithhypoplasticlungsand/orrenalfailure.,Terminology,Cysticdysplasiadysplastickidneyscanbeunilateralorbilateral,usuallycontaincystsandaredisorganized,containingectopictissuesuchascartilageandmuscle.Theymayfunction.Ultrasonicallytheyusuallyappearsmallandechogenicwithsmallperipheralcorticalcysts.Whiledysplastickidneysareoftenhypoplastic,notallsmallkidneysaredysplastic.Theclinicalfeaturesareveryvariablefromanormalappearingneonatetoaverydysmorphicinfant.Dysplastickidneysareassociatedwithurinarytractobstruction,andmanysyndromesareassociatedwithcysticdysplastickidneys.Bilateralrenaldysplasiawillresultinprogressiverenalfailure.,Polycystickidneydiseasereferstotwoconditions:autosomalrecessivepolycystickidneydiseaseandautosomaldominantrenaldisease.,Autosomalrecessivepolycystickidneyswerepreviouslyknownasinfantilepolycystickidneys.Confusinglythesekidneysappearhighlyechogeniconultrasound.Thereisgeneralizeddilationofthecollectingtubules.Autosomaldominantrenaldiseasewaspreviouslyknownasadultpolycystickidneydisease.Cystsdevelopanywherealongthenephron.,Theultimatediagnosisofthecysticrenaldisorderisnotdependentonanyoneimagingmodalityandwilldependonmanyfactors.Sourcesofinformationwhentryingtocometothediagnosisshouldbecollatedfrommanyareas,suchas:,obstetrichistoryofthemotherprenatalhistoryandfetalultrasonographyfamilyhistoryinformationclinicalexaminationofthechildradiologyofpatientandparentslaboratorydata,forexampleDNApathologyifabiopsyistakenorfromanyotherfamilymembersthatmayhavehadabiopsyornephrectomyinthepast.,Ultrasoundisstilltheimagingmodalityofchoiceinchildren,andthefindingsonultrasoundwilldirectfurtherimagingasrequired.Theultrasoundapproachtoanycysticrenaldiseaseinchildrenmustincludeobservationsaboutthefollowing,whichshouldbecarefullystatedintheultrasoundreport.,unilateralorbilateralrenalcysts(bilateralinvolvementismorecommoninthegeneticallyinheritedconditions)sizeofthekidneysaretheylargeorsmall?localizationtoonepartofthekidneyordiffuseinvolvementofthewholekidney.Isthereacapsulearoundthecysts?extrarenalcysts,inparticularintheliverorpancreasliversizeandhepaticparenchymaappearancepresenceofalargespleenandportalhypertension.,Renalcystsarecommonandmaybehereditary,developmentaloracquired.Theclassificationofcysticrenaldiseasevariesaccordingtotheperspectivefromwhichitiswritten,anddespiteavastamountofliteratureonthesubject,thereisstillnogenerallyacceptedclassificationinexistence.TheearlyPotterclassificationisoflimitedvalueforclinicalpracticebecausenotalltypesrepresentclinicalentities.,Thefollowingclassificationisbynomeansallinclusivebutaimstoemphasizetheimportantclinicalcysticdisorderslikelytobeencounteredbythesonographer.Broadlyspeaking,cysticdiseaseofthekidneyscanbedividedintotwogroupsgeneticdiseaseandnon-geneticdisease:,Geneticdiseaseautosomalrecessivepolycystickidneydisease(ARPKD)autosomaldominantpolycystickidneydisease(ADPKD)juvenilenephronophthisisandmedullarycysticdiseasecomplexglomerulocystickidneydiseasecystswithmultiplemalformationsyndromes;,Non-geneticdiseasesimplecystsmulticysticdysplastickidneymultilocularcystsacquiredrenalcysticdisease(chronicrenalfailure)calicealdiverticulummedullaryspongekidney.,Geneticdisease,Autosomalrecessivepolycystickidneydisease(ARPKD)Thisisageneralizedcysticdilationoftherenalcollectingtubulessothatthekidneysarepackedtoagreaterorlesserdegreewithtinylittlecysts(Fig.3.31).Itismuchrarerthantheautosomaldominantformandoccursin1in50000people.Prenataldiagnosiscanbemadebuttherearefalsepositiveandfalsenegativediagnoses.CongenitalhepaticfibrosisisaprerequisiteforthediagnosisofARPKD.,Figure3.31Autosomalrecessivepolycystickidneydisease(ARPKD).(A)CutsectionofapostmortemspecimeninapatientwithARPKD.Therearemultiplesmallcyststhroughoutthewholeoftherenalsubstance.Itisthesemultiplecystswiththeirposterioracousticenhancementwhichgivethehyperechogenicappearancesonultrasound.(BD)SonogramsofthekidneyinthreepatientswithARPKDtodemonstratethewidevariationinappearance.Thekidneysarealllarge,overthe95thcentile,andaregloballyhyperechoic.Thevisiblecystsaregenerallysmall,rarelyexceeding2cm.Sometimestheincreaseinechogenicityisprimarilymedullary.,A,B,C,D,TherearetwotypesofpresentationofARPKDdependingontheageofthepatientandthedominanceoftherenalorthehepaticdisease.Inthosechildrenwhopresentatbirthorduringtheneonatalperiodtherenaldiseasedominates,whileinthosewhopresentlaterinchildhoodoradolescencetheliverdiseasedominates,withmuchmilderrenalmanifestations.Thehepaticdiseaseinthesechildreniscalledcongenitalhepaticfibrosiswithrenaltubularectasiaandcomestomedicalattentionbecauseoftheproblemsassociatedwithhepaticfibrosis,suchassplenomegaly,portalhypertension,varicesandbleeding.,GrosscysticdilationoftheintrahepaticbiliarytreeisusuallycalledCarolisyndrome.Theoriginaldescriptionwaspurelyofthehepaticdisease,butdilationofthebileductsisseeninearlypresentingARPKDandinthemilderendoftherenalspectrumofrenaltubularectasia.Theriskforasiblingofhavingthisconditionis25%,andtheparentskidneysshouldbenormal.,SonographicAppearancesThereisawidespectrumofappearancesfrombirthandwithincreasingagethroughoutchildhood.Thereisbilateralequalinvolvementofthekidneys,andthereniformshapeisusuallymaintained.Thekidneysmustbebigandaregenerallyoverthe90thcentileforageintheyoung.Withincreasingageandprogressionoftherenaldisease,fibrosismayresultinstabilizationandcomparativedecreaseintherenalsize.,Theinhomogeneousglobalincreaseinechotextureisduetothemyriadofmicrocystspresentingmultipleacousticinterfaces.Insomeasubcapsularrimofnormalhypoechoiccortexisdiagnostic.Medullarypyramidsmaybehypoechoicatbirthinsomelessseverelyaffectedbutovertimebecomehyperechoic.Inolderchildrenthecorticomedullarydifferentiationisusuallylost.,Visiblemacrocystsareuncommonbutcanbeseen,andtheyaregenerallynomorethan12cmindiameter.Theybecomemorecommonwithage.Hepaticfibrosisisalwayspresent.Thehepaticechotexturemaybenormalbut,withincreasingfibrosis,willbecomecoarseandincreasedparticularlyintheperiportalregion.,Figure3.32Dilatedbileductsinautosomalrecessivepolycystickidneydisease(ARPKD).Longitudinalsonogramofthelivershowingthedilatedcysticspaces.Thesearenotcystsbutdilationsofthebileducts.ThelivershouldalwaysbecarefullyexaminedinallchildrensuspectedofhavingARPKD.,Thelivermustbecarefullyexaminedforlesionswhicharecysticdilationsofthebiliarytree.Thehepaticcysticlesionsarenottruecystsbutratherout-pouchingsofthebileducts(Fig.3.32).,Inolderchildren,becauseofthehepaticfibrosisandliverdisease,portalhypertensionmaybepresent.Evidenceofportalhypertensionwithanenlargedspleenandvaricesmustbesought.Dopplerexaminationoftheliver,spleenandportalsystemisanessentialpartoftheexaminationinthesechildren.,FurtherimagingWhenthechildisolderandovertheneonatalperiod,anIVUisperformed.ThiswilldemonstratethestreakyradiatingpatternofcontrastwhichisalmostpathognomonicofARPKD(Fig.3.33).Theimportanceofdoingthisexaminationisthatinshowingthecalicealpatternitwillhelpexcludeothercausesoflargeechogenickidneysintheneonatalperiod,suchasdysplasia.,A,B,Figure3.33Intravenousurogram(IVU)inautosomalrecessivepolycystickidneydisease(ARPKD).(A)&(B)TwoexamplesoftheIVUappearancesofARPKD.Theurogramshouldalwaysbeperformedtodemonstratethecalicealpattern.Thiswilldemonstratethetypicalradiatingappearanceofthecontrastasitpassesthroughthecollectingsysteman