Neural tube defects - in neonates and children

Neural tube defects

1. NEURAL TUBE DEFECTS
MRS BINCY VARGHESE
ASSOCIATE PROFESSOR
NURSING

2. INTRODUCTION
Neuraltubedefects(NTDs)areoneofthemostcommon
congenitalcentralnervoussystem(CNS)malformations.
Developbetweenthe3
rd
and4
th
weekofpregnancyand
areoftencausedbyfolicaciddeficiency.Thedeficiency
resultsinimproperclosureoftheneuralplateinthe
embryo,mainlyatthecaudalorcranialends.
Themostcommontypeofbirthdefectsandarethought
tohavemultifactorialetiology.

3. ThediagnosisofNTDs isoftenestablished
duringpregnancyviaUltrasoundanddetectionof
elevatedAlpha-fetoproteinlevels.
Treatment involvesprophylacticadministration
ofantibioticsandswiftsurgicalclosureofthedefectto
avoidCNSinfections.Supplementationwithfolicacidisan
importantpreventativemeasureandshouldideallybe
initiated4weekspriortoconception.

4. DEFINITION
NeuralTubeDefects(NTDs)areaheterogeneousgroupof
malformationsresultingfromfailureofneuraltubeclosure
betweenthethirdandfourthweekofembryologic
development.
Neural tube defects are a group of
congenitalmalformationsoftheBrainandSpinalCord.They
arecausedbyimproperclosureoftheneuralplateinthe
embryoresultinginmalformationsoftheCentralNervous
System(CNS),SpineandCranium.

5. ETIOLOGY
1.Neurulationisdefinedastheembryonicprocessthatleadsto
theultimatedevelopmentoftheneuraltube,theprecursorto
thebrainandspinalcord.Therearetwodistinctphasesof
neurulation.
Intheprimaryphase(weeks3–4)thebrainandtheneural
tubeformfromthecaudalregiontotheuppersacrallevel.
Secondaryneurulation(weeks5–6)completesthedistal
sacralandcoccygealregions.
Thefailureofneurulationatanystageleadstotheformationof
aneuraltubedefect.

6. 2.MultifactorialGeneticandEnvironmentalFactorshavebeen
implicatedinthepathogenesisofNeuralTubeDefects
(NTDs).
ThemostcommonhistoricalcauseofNTDsgloballyis
folatedeficiencyinthematernaldiet.
Consanguineousmarriages
Chromosomal abnormalities(Trisomy13:Patau
syndrome,Trisomy18:Edward’ssyndrome,Trisomy21:
Down’ssyndrome)arealsoassociatedwithNTDs.
Associated maternal conditions: Diabetes
mellitus,Obesity,Fever/Hyperthermiaduringfirst
trimester

7. 3.Single-gene(autosomalrecessive)disorders
Meckelsyndrome:Rare,characterisedbycongenital
anomaly;brainmalformation,largepolycystickidneys,cleft
lip/cleftpalate,cardiacanomalies.
Robertsyndrome:Raredisordercharacterisedbygrowth
delays,malformationofarmsandlegs,abnormalitiesof
craniofacialregion.
Jarcho-Levinsyndrome:Raredisordercharacterisedby
defectsofspine,ribs.

8. 5.Teratogens
Valproicacid:Antiepilepticdrug
Carbamazepine:Antiepilepticdrug
Aminopterin:Antineoplasticagent
Thalidomide:Immunosuppressiveagent
Oralisotretinoin:VitaminAderivative

9. CLASSIFICATION
NTDscanbeclassifiedas“Open”or“Closed”types,basedon
embryologicalconsiderationsandthepresenceorabsenceof
exposedneuraltissue.
OpenNTDs
InvolvemultipleaspectsoftheCNSandareduetofailureof
primaryneurulation,thustheneuraltubefailsto
appropriatelyclosealongthedorsalmidline.
Neuraltissueiscompletelyexposedorcoveredbya
membranewithassociatedcerebrospinalfluid(CSF)leakage.

10. OpenNTD’srepresentroughly80%ofallNTD’s
OpenNTDsoccurwhenthebrainand/orspinalcordare
exposedatbirththroughadefectintheskullorvertebraewith
themostcommonbeingSpinabifida(Meningocele,
Myelomeningocele),Myelocele,Encephalocele and
Anencephaly.

11. ClosedNTDs
LocalizedandconfinedtotheSpine(theBrainisrarely
affected)andresultfromadefectinsecondaryneurulation.
Neuraltissueisnotexposedandthedefectisfullycovered
byepitheliumalthoughtheskincoveringthedefectmaybe
dysplastic(i.e.,tuftofhair,dimple,birthmarkorother
superficialabnormality).
Common examples of closed NTDs
areLipomyelomeningocele,Lipomeningoceleand Teth
heredcord.

12. Anatomical Classification of Neural Tube Defects
Cranial defects
Spinal defects

13. SPINA BIFIDA
Spinabifidaisabirthdefectinwhichthereisincomplete
closingofthespineandthemembranesaroundthespinal
cordduringearlydevelopmentinpregnancy.
ThetermbifidaisfromtheLatin”bifidus”or"leftin2
parts."Althoughtheconditionhasalsobeenreferredtoas
Myelodysplasia.
Spinabifidaisatreatablespinalcordmalformationthat
occursinvaryingdegreesofseverity.
Spinabifidaisavariabledefectinwhichthevertebralarch
ofthespinalcolumniseitherincompletelyformedor
absent.

14. Classification
SpinaBifidaCystica
Spinabifidacysticacanoccuranywherealongthespinalaxis
butmostcommonlyisfoundinthelumbarregion.Inthis
condition,thespineisbifidandacystforms.
SpinaBifidaCysticacanthenbebrokendowninto
MeningoceleandMyelomeningocele.
Meningocele
Inthisform,asingledevelopmentaldefectallows
themeningestoherniatebetweenthevertebrae.Asthe
nervoussystemremainsundamaged,individualswith
Meningoceleareunlikelytosufferlong-termhealthproblems.

15. MENINGOCOELE

16. Myelomeningocele
Myelomeningocele(MMC)alsoknownas“Meningomyelocele”is
thetypeofSpinaBifidathatoftenresultsinthemostsevere
complicationsandaffectstheMeningesandNerves.
InindividualswithMyelomeningocele,theunfusedportionofthe
spinalcolumnallowsthespinalcordtoprotrudethroughan
opening.
Myelomeningoceleoccursinthethirdweekofembryonic
development.

17. Themeningealmembranesthatcoverthespinalcordalso
protrudethroughtheopening,formingasacenclosingthespinal
elementssuchasMeninges,Cerebrospinalfluid,andpartsofthe
spinalcordandnerveroots
AchildbornwithMyelomeningocelerequiresspecialtycarewhere
NeonatalsurgeryandClosurecanbeperformed.(Surgeryinvolves
freeinglateralmusclesandskinforcoverageandattemptingto
formaclosure).

18. MYELOMENINGOCELE

19. SpinaBifidaOcculta
OccultaisLatinfor"hidden".ThisisthemildestformofSpina
bifida.
Failureofoneormorevertebraetoclosecompletely;
thespinalcord,spinalmeninges,andoverlyingskinremain
intact.
Usuallyasymptomatic
Inocculta,theouterpartofsomeofthevertebraeisnot
completelyclosed.Theskinatthesiteofthelesionmaybe
normal,oritmayhavesomehairgrowingfromit;theremay
beadimpleintheskin,orabirthmark.
MostpeoplearediagnosedincidentallyfromspinalX-rays.

20. Clinical features of Spina Bifida
Ingeneral,infantswithSpinaBifidaCysticapresentwiththefollowing:
Lethargy
Poorfeeding
Irritability
Stridor
Ocularmotorincoordination
Developmentdelay

21. Olderchildrenmaypresentwiththefollowing:
Cognitiveorbehavioralchanges
Decreasedstrength
Changesinbowelorbladderfunction
Lowercranialnervedysfunction
Backpain
Worseningspinalorlowerextremityorthopedicdeformities

22. Diagnostic Evaluation
Alpha-Fetoprotein
TheAFPleveliselevatedin70-75%ofcasesinwhichthefetus
hasanopenspinabifida.
FetalUltrasonography
SomeCentresuseFetalUltrasonographyastheprimary
screeningtoolforneuraltubedefects,usuallyatapproximately
18weeksgestationalage.Thecombinationofmaternalserum
AFPscreeningwithsecond-trimesterultrasonographic
screeningdetectsover90%ofneuraltubedefectsfrom20
weeks'gestation.

23. GaitAnalysis
Gaitanalysishasbeenintroducedtoevaluatepatients
functionally.Itisalsousedtostudymuscleinnervation,
strength,andcoordinationpatterns,whichmayinterferewith
ambulationorwithapatient'sabilitytoliveindependently.
Gaitanalysismayserveasausefulpreoperativediagnostic

24. CTScanandMRI
Magneticresonanceimaging(MRI)ofthespineandbrainis
helpfulinneurologicassessmentandprovidesabaselinefor
comparisoninfutureinvestigations,especiallyinthecontextof
progressiveneurologicdeterioration
Radiography
Radiographsofthevertebraeprovideinformationforearly
evaluation

25. Management
Bracing
Thegoalofbracingistoallowpatientstofunctionatthe
maximumlevelpermittedbytheirneurologiclesionand
intelligence.Bracingalsoensuresanormaldevelopmental
progression,itsaimbeingtoenablepatientstoambulateandto
participateinappropriateage-relatedactivities.
Ininfantsaged9monthsandyounger,sittingbalanceand
supportmaybeprovidedwithastandardcarseat,elevated45-
60°.Acarseatmaybeappropriatetomaintainmobilitywith
headandtrunkcontrolandtoincreaseupper-extremitystrength
inchildrenasoldas18months.

26. AStandingFramemaybeusedforthoseaged1-2yearsto
diminishthedegreeofosteoporosisandtolimitthecontracture
ofthehip,knee,andankle.
AParapodiummaybehelpfulforchildrenaged3-12years,
allowingthemtogaingreaterexperienceinstandingandin
manipulatingworkwiththeirupperextremitiesatatableor
AWheelchaircanprovidemobilityandoftenisusedwitha
moldedankle-footorthosis.

27. STANDING FRAME PARAPODIUM

28. ANKLE ORTHOSIS KNEE ANKLE ORTHOSIS
HIP KNEE ANKLE
ORTHOSIS

29. PhysicalTherapy
TheTherapyprogramsshouldbedesignedtoparallelthenormal
achievementofgrossmotormilestones.
Asthechilddevelops,theTherapistmonitorsjointalignment,muscle
imbalances,contractures,posture,andsignsofprogressiveneurologic
dysfunction.
ThePhysicaltherapistalsoprovidescaregiverswithinstructionin
handlingandpositioningtechniquesandrecommendsorthotic
positioningdevicestopreventsofttissuecontractures.
Forpatientswhoarenotlikelytobecomeambulatory,placeemphasis
ondevelopingproficiencyinwheelchairskills.
Forpatientswhoarepredictedtoambulate,Pregaittrainingshould
beginwithuseofaParapodium.

30. RecreationalTherapy
ChildrenwithMyelomeningoceleoftenexperiencerestricted
andrecreationalopportunitiesbecauseoflimitedmobilityand
physicallimitations.
Recreationaltherapyprovidesopportunitiesforparticipationin
adaptedsportsandexerciseprograms,whichcanresultin
long-terminterestinpersonalfitnessandhealth.
MyelomeningoceleClosure
ClosureoftheMyelomeningoceleisperformedimmediately
birthifexternalcerebrospinalfluid(CSF)leakageispresent.In
theabsenceofCSFleakage,closuretypicallyoccurswithinthe
first24-48hours.

31. ShuntingforHydrocephalus
AlthoughinafewcasesHydrocephalusarrestsspontaneously,
80-90%ofchildrenwithMyelomeningoceleultimatelyrequire
Shunting(HollowtubeplacedinBrain/SpinetodrainCSFor
redirectittoanotherlocationofbodywhereitcanbe
reabsorbed.
Ventriculoperitonealshuntingisthepreferredmodality
(ProcedureinwhichadeviceisusedtodrainCSFfromBrainto
peritonealcavity).Alternativesincludeventriculoatrialand
ventriculopleuralshunting.

32. OrthopaedicProcedures
MusculoskeletalproblemsinMyelomeningocelecanbe
congenitaloracquiredandoftenrequireOrthopedic
intervention.
Orthopedicsurgeriesaredirectedtowardfunctional
improvementasopposedtocorrectionofradiologicfindings.
SpinaldeformitiesarecommoninMyelomeningocele,and
progressiveKyphosisorScoliosismayleadtoadeclinein
functionalstatusandtoanincreasedriskforthe
ofDecubitusUlcersandcardiopulmonarycompromise.

33. SpinalOrthoticDevicesmayserveasatemporizingmeasure.
Becausemuscleimbalancecausesprogressive,resistant
deformities,thepatientwithspinabifidamustbeevaluated
frequentlybymembersofhisorhersupportteam.Inthisway,
theycanassessmusclegroups,emphasizetheneedfor
balancetopreventdeformities

34. ENCEPHALOCELE/ MENINGOENCEPHALOCELE
Encephaloceleisaneuraltubedefectcharacterizedbysac-like
protrusionsofthebrainandthemembranesthatcoverit
throughopeningsintheskull.
Thesedefectsarecausedbyfailureoftheneuraltubetoclose
completelyduringfetaldevelopment.
Insomecases,cerebrospinalfluidormeningesmayalso
protrudethroughthisgap.Theportionofthebrainthatsticks
outsidetheskullisusuallycoveredbyskinorathinmembrane
sothatthedefectresemblesasmallsac.

35. Protrudingtissuemaybelocatedonanypartofthehead,but
mostoftenaffectstheoccipitalarea.
MostEncephalocelesarelargeandsignificantbirthdefectsthat
arediagnosedbeforebirth.However,inextremelyrarecases,
someencephalocelesmaybesmallandgounnoticed.

36. Etiology
Althoughtheexactcauseisunknown,Encephalocelesare
causedbyfailureoftheneuraltubetoclosecompletely
duringfetaldevelopment.
ResearchhasindicatedthatTeratogenslikeTrypanblue(a
stainusedtocolorcellsblue)andArsenicmaydamage
developingfetusandcauseEncephaloceles.

37. ClinicalFeatures
Delaysinreachingdevelopmentalmilestones
Intellectualdisability
Learningdisabilities
Growthdelays
Seizures

38. Visionimpairment
Uncoordinatedvoluntarymovements(ataxia)
Hydrocephalus,aconditioninwhichexcesscerebrospinal
fluidintheskullcausespressureonthebrain.
Progressiveweaknessandlossofstrengthinthearmsand
legsduetoincreasedmuscletoneandstiffness(spastic
paraplegia).

39. DiagnosticEvaluation
USG
FetalCTScan/MRI
Management
Currently,theonlyeffectivetreatmentforEncephaloceles
reparativesurgery,generallyperformedduringinfancy.
Occasionally,shuntsareplacedtodrainexcess
cerebrospinalfluidfromthebrain

40. ANENCEPHALY
Anencephalyisaseriousdevelopmentaldefectofthecentral
nervoussysteminwhichthebrainandcranialvaultaregrossly
malformed.Thecerebrumandcerebellumarereducedorabsent
butthehindbrainispresent.

41. Etiology:
Geneticandenvironmentalfactors:
ThespecificgenesthataremostimportantinNTDshave
yetbeenidentified,althoughgenesinvolvedinfolate
metabolismarebelievedtobeimportant.Onesuchgene,
Methylenetetrahydrofolatereductase(MTHFR),hasbeen
showntobeassociatedwiththeriskofNTDs.
Valproicacid,ananticonvulsanthavebeenshownto
increasethechanceofanNTD

42. Maternaltype1,orInsulin-dependentdiabetesmellitus
(IDDM),confersasignificantincreaseintheriskforNTDs
Maternalhyperthermiahasbeenassociatedwithan
increasedriskforNTD;therefore,pregnantwomenshould
avoidhottubsandotherenvironmentsthatmayinduce
transienthyperthermia.

43. Clinical features
baby born with anencephaly is usually blind, deaf, unaware
its surroundings and unable to feel pain.
Diagnostic evaluation
USG
Maternal AFP level

44. Prognosis
ThereisnocureorstandardtreatmentforAnencephaly
andtheprognosisforpatientsisdeath.
Infantsthatarenotstillbornwillusuallydiewithinafew
hoursordaysafterbirthfromcardiorespiratoryarrest

45. ANENCEPHALY

46. CLOSED NTDs

47. Tethered cord syndrome
Tetheredcordsyndrome(TCS)referstoagroupof
neurologicaldisordersthatrelatetomalformationsofthe
spinalcord.
Abnormalstretchingofthespinalcordcausedbyadhesions
orobstructionsthattetherthecordtothebaseofthespinal
canal
Etiology:Tumour,Meningealadhesions,Lipoma,Cysts
Symptoms:Backpain,sensorymotordeficits,skeletal
deformities(scoliosis),bladder/boweldysfunction,skinlesions
inlowerback
Diagnosis:CTscan,MRI
Management:Surgicalremovalandrepair

49. LIPOMYELOMENINGOCOELE
Lipomyelomeningoceleisaconditioninwhichanabnormal
growthoffat(lipo)attachestothespinalcord(myelo)andits
membranes(meninges).
Symptomscanincludeproblemswithbowelandbladderfunction,
frequenturinarytractinfections,backandlegpain,muscle
weaknessorsensorylossinthelegs,neuromuscularscoliosis,foot
andlegorthopedicabnormalities,anddifficultywalking.
DuringsurgeryforLipomyelomeningocele,thepediatric
neurosurgeonwillfreethespinalcordfromitsattachmenttothe
lipoma,removeasmuchofthelipomaassafelypossible,and
closethemembranesoverthespinalcord.
Thegoalsofthesurgeryaretopreventdeteriorationof
neurologicalfunctioninthefutureandtopreserveorimprove
currentfunction.

50. ROLE OF FOLIC ACID
Maternalmalnutritionisanimportantriskfactorfordevelopmentof
NTD.Studiestilldatehaveshowndecreasedmaternalfolatelevelsin
NTDaffectedpregnancies.
Periconceptionalfolicacidsupplementationhasshowntodecreaseboth
theoccurrenceandrecurrenceofNTD,thoughtheexactmechanismfor
thisprotectiveeffectremainsunknown.
FolicacidisaBgroupvitamin,firstisolatedfromspinachleafin1941.
Folicacidoccursnaturallyasfolates,whicharetemperatureandstorage
sensitiveandcookingcausessignificantfallintheirconcentration.
Sourcesrichinfolatesareliver,greenleafyvegetablesespeciallyspinach
andbroccoli,nuts,egg,cereals,cheese,fruits,yeast,beansetc.

51. Folicacidisplayanimportantroleincelldivisionanddevelopment.
Folicacidishighlyrecommendedforpreventingbothoccurrenceand
recurrenceofNTD.
Strategiesforimprovingmaternalfolatestatus:
Dietarymodifications:Dietaryrecommendationsofconsumingfood
highinfolatecontentisbeneficial.
Vitaminsupplementation:Thesecondapproachisdailyfolicacid
supplementationtoallwomeninthereproductiveagegroup(18-44
years).

52. Advisewomentryingtoconceivetotakeadoseof400μgfolicacid
daily,startingtwomonthsbeforetheplannedpregnancy.
Advisewomenwhohavenotbeensupplementingtheirdietandwho
suspectthemselvestobepregnanttobegintaking400μgfolicacid
dailyandtocontinueuntiltheyare12weekspregnant.
CounselpregnantwomenwhopreviouslyhadababywithNTD,For
womenwithDiabetesorwhoaretakinganticonvulsantaboutthe
havingababybeingaffected.Advisethemtotake5mgFolicacid
andtoincreasetheconsumptionofFolateindiet.

53. THANK YOU