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OB Case Study:OB Case Study:AnencephalyAnencephalyAnencephalyAnencephaly

Daniel EnriquezDaniel Enriquez

Medical Sonography StudentMedical Sonography Student

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Table of ContentsTable of Contents

�� Neural Tube FormationNeural Tube Formation

�� What is Anencephaly?What is Anencephaly?

�� Characteristics of Characteristics of AnencephalyAnencephaly

�� OccurrenceOccurrence

�� Sonographic FindingsSonographic Findings

�� Patient HistoryPatient History

�� Case ImagesCase Images

�� CausesCauses

�� RisksRisks�� OccurrenceOccurrence

�� TheoryTheory

�� AcraniaAcrania

�� Anencephaly: What is Anencephaly: What is Left?Left?

�� Associated FindingsAssociated Findings

�� Lab ValuesLab Values

�� RisksRisks

�� PrognosisPrognosis

�� Prevention / PlanningPrevention / Planning

�� ArticlesArticles

�� Interview with Dr. ShaverInterview with Dr. Shaver

�� ReferencesReferences

�� QuizQuiz

Neural Tube FormationNeural Tube Formation

�� Neural plate appears Neural plate appears during 3rd weekduring 3rd week

�� Neural plate gives rise Neural plate gives rise �� Neural plate gives rise Neural plate gives rise to neural foldsto neural folds

�� Neural tube closes by Neural tube closes by 44thth weekweek

–– Cephalic endCephalic end

–– Caudal endCaudal end

www.geol.umd.edu


�� Failure of the neural Failure of the neural folds to fuse can lead folds to fuse can lead to NTDs:to NTDs:to NTDs:to NTDs:

–– AnencephalyAnencephaly

–– Spina bifidaSpina bifida

–– EncephaloceleEncephalocele

www.biocura.co.za


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What is Anencephaly?What is Anencephaly?

�� Failure of closure of Failure of closure of one of the anterior one of the anterior neuroporesneuroporesneuroporesneuropores

�� Most severe neural Most severe neural tube defecttube defect

�� Most common NTDMost common NTD

www.i-am-pregnant.com

What is Anencephaly?What is Anencephaly?

�� AnAn-- = without= without

�� Encephal/o = brainEncephal/o = brain

�� MeroencephalyMeroencephaly

�� MeroMero-- = partial= partial

www.buzzle.com

Characteristics of AnencephalyCharacteristics of Anencephaly

�� Partial absence of the Partial absence of the brainbrain

–– CerebrumCerebrum–– CerebrumCerebrum

–– CerebellumCerebellum

–– Basal gangliaBasal ganglia

�� Absence of cranial Absence of cranial vaultvault

�� Only brainstem leftOnly brainstem left

www.healthofchildren.com

Characteristics of AnencephalyCharacteristics of Anencephaly

�� Occurs superior to the Occurs superior to the orbitsorbits

�� Facial features are Facial features are �� Facial features are Facial features are preservedpreserved

�� Base of skull remainsBase of skull remains

�� Incompatible with lifeIncompatible with life

OccurrenceOccurrence

�� At least 1 to 2 in 1000 At least 1 to 2 in 1000 births in USbirths in US

�� Highest incidence in Highest incidence in �� Highest incidence in Highest incidence in United Kingdom (3.5 United Kingdom (3.5 per 1000)per 1000)

www.broadvoice.com

OccurrenceOccurrence

�� 4 times more 4 times more common in females common in females (males tend to have (males tend to have (males tend to have (males tend to have lower spinal defects)lower spinal defects)

�� 6 times more 6 times more prevalent in whitesprevalent in whites

�� Recurrence is 3% to Recurrence is 3% to 5%5%

TheoryTheory

Failure of cranial end of neural tube to close by 4th week

TheoryTheory

Failure of cranial end of neural tube to close by 4th week =

TheoryTheory


NTDNTD=

TheoryTheory


NTDNTD=

TheoryTheory


Abnormal development of calvaria

NTDNTD=

TheoryTheory



NTDNTD=

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TheoryTheory



NTDNTD

ACRANIAACRANIA

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TheoryTheory



NTDNTD

ACRANIAACRANIA

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TheoryTheory



NTDNTD

ACRANIAACRANIA

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Protrusion of the brain from the cranium

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TheoryTheory



NTDNTD

ACRANIAACRANIA

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Protrusion of the brain from the cranium

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TheoryTheory



NTDNTD

ACRANIAACRANIA

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Protrusion of the brain from the cranium EXENCEPHALYEXENCEPHALY

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TheoryTheory



NTDNTD

ACRANIAACRANIA

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TheoryTheory



NTDNTD

ACRANIAACRANIA

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Without the protection of the skull, the brain is exposed and undergoes degeneration


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TheoryTheory



NTDNTD

ACRANIAACRANIA

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TheoryTheory



NTDNTD

ACRANIAACRANIA

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ANENCEPHALYANENCEPHALY

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AcraniaAcrania

�� Also known as Also known as exencephalyexencephaly

�� Occurs at the beginning Occurs at the beginning of 4th GA weekof 4th GA week

�� Skull mineralization Skull mineralization �� Skull mineralization Skull mineralization begins at 9 weeksbegins at 9 weeks

�� Skull bones fail to Skull bones fail to mineralizemineralize

�� Normal bone should be Normal bone should be echogenicechogenic www.ultrasound-images.com

AcraniaAcrania

�� Can be diagnosed at 12 Can be diagnosed at 12 weeksweeks

�� Mickey Mouse head Mickey Mouse head (bilobed brain (bilobed brain appearance)appearance)appearance)appearance)

�� Believed to be a Believed to be a predecessor of predecessor of anencephalyanencephaly

�� True acrania is absence True acrania is absence of entire skull (including of entire skull (including skull base)skull base)

www.obgyn.net

Anencephaly: What is Left?Anencephaly: What is Left?

�� A mass that is:A mass that is:

–– SpongySpongy

–– VascularVascular

–– Mostly composed of Mostly composed of hindbrainhindbrainhindbrainhindbrain

–– Rudimentary brain Rudimentary brain stemstem

–– Functioning neural Functioning neural tissuetissue

www.neuropathology.neucom.edu

Angiomatous Stroma / Angiomatous Stroma / CerebrovasculosaCerebrovasculosa

�� Thick membraneThick membrane

�� Covers remnants of Covers remnants of brainbrain

www.neuropathology.neucom.edu

brainbrain

Associated FindingsAssociated Findings

�� Polyhydramnios (no Polyhydramnios (no control of swallowing)control of swallowing)

�� Spina bifidaSpina bifida

�� Craniorachischisis Craniorachischisis �� Craniorachischisis Craniorachischisis (congenital fissure of (congenital fissure of the skull and vertebral the skull and vertebral column)column)

�� Cleft lip and palateCleft lip and palate

http://www.jle.com/en/revues/medecine/mtg/e-docs/00/04/40/1D/article.md?fichier=images.htm


�� HydronephrosisHydronephrosis

�� Diaphragmatic herniaDiaphragmatic hernia

�� Cardiac defectsCardiac defects�� Cardiac defectsCardiac defects

�� OmphaloceleOmphalocele

www.nlm.nih.gov


�� GI defectsGI defects

�� TalipesTalipes

�� Dysraphism (widening Dysraphism (widening of upper cervical of upper cervical of upper cervical of upper cervical spine)spine)

�� Iniencephaly Iniencephaly (retroflexed fetal (retroflexed fetal head due to lack of head due to lack of cervical vertebrae)cervical vertebrae)

www.library.med.utah.edu

Lab Values: AFPLab Values: AFP

�� Elevated maternal Elevated maternal serum alphaserum alpha--fetoprotein (MSAFP)fetoprotein (MSAFP)

–– Synthesized in yolk sac Synthesized in yolk sac and later in fetal liverand later in fetal liverand later in fetal liverand later in fetal liver

–– Detected in fetal spine, Detected in fetal spine, GI tract, liver, and GI tract, liver, and kidneyskidneys

–– Peaks between 15 and Peaks between 15 and 18th GA week18th GA week

www.waze.com

Lab Values: AFPLab Values: AFP

�� Elevated maternal Elevated maternal serum alphaserum alpha--fetoprotein (MSAFP)fetoprotein (MSAFP)–– Cuttoff is 2.0 or 2.5 Cuttoff is 2.0 or 2.5

MoM (multiples of the MoM (multiples of the MoM (multiples of the MoM (multiples of the median)median)

–– Detection rate for Detection rate for anencephaly is 95% or anencephaly is 95% or higherhigher

–– Levels with Levels with anencephaly are >5.0 anencephaly are >5.0 MoMMoM

www.themedica.com

Lab Values: AcetylcholinesteraseLab Values: Acetylcholinesterase

�� Exposed neural tissue Exposed neural tissue in amniotic fluidin amniotic fluid

�� Found also in Found also in �� Found also in Found also in maternal bloodmaternal blood

www.eyepathologist.com

Lab Values: Other TestsLab Values: Other Tests

�� AmniocentesisAmniocentesis

�� Triple screen Triple screen �� Triple screen Triple screen

�� Karyotype testing Karyotype testing

www.riversideonline.com

Sonographic FindingsSonographic Findings

�� Embryo’s head Embryo’s head identified by US at identified by US at 7weeks7weeks

�� Normal amounts of Normal amounts of brain can be seen in brain can be seen in brain can be seen in brain can be seen in 1st trimester (even 1st trimester (even with anencephaly)with anencephaly)

�� Cranial vault does not Cranial vault does not ossify until after 1st ossify until after 1st trimestertrimester

www.brown.edu


�� Normal cranial Normal cranial anatomy can be anatomy can be visualized after 12 to visualized after 12 to 14 weeks GA14 weeks GA

�� CRL may be normal CRL may be normal �� CRL may be normal CRL may be normal early in GAearly in GA

�� Absence of brain and Absence of brain and cranial vaultcranial vault

�� Absence of parietal Absence of parietal and frontal bonesand frontal bones

www.msdlatinamerica.com


�� Folding of the earsFolding of the ears

�� CerebrovasculosaCerebrovasculosa

�� Froglike appearance Froglike appearance �� Froglike appearance Froglike appearance (bulging orbits) due (bulging orbits) due to absent frontal boneto absent frontal bone

www.fetalultrasound.com

Patient HistoryPatient History

�� 2525--year oldyear old

�� FemaleFemale

�� G1G1G1G1

�� 24w 3d Gestational Age24w 3d Gestational Age

�� No known history of genetic diseaseNo known history of genetic disease–– Patient refused sequential screeningPatient refused sequential screening

�� No known complications with this pregnancyNo known complications with this pregnancy

�� No prenatal or ultrasound history during early No prenatal or ultrasound history during early gestation due to socioeconomic reasonsgestation due to socioeconomic reasons

www.dailyspark.com

Case Images: UltrasoundCase Images: Ultrasound










CausesCauses

�� Multifactorial (genetic Multifactorial (genetic + environmental)+ environmental)

�� Amniotic band Amniotic band syndrome?syndrome?syndrome?syndrome?

–– AmputationsAmputations

–– EntanglementEntanglement

�� MeckelMeckel--Gruber Gruber syndrome?syndrome?

�� Trisomy 13?Trisomy 13?www.jeanapettus.webs.com

RisksRisks

�� Diabetes mellitusDiabetes mellitus

�� HyperthermiaHyperthermia

�� Valproic acid (an Valproic acid (an �� Valproic acid (an Valproic acid (an antiepileptic drug)antiepileptic drug)

�� Folate and vitamin Folate and vitamin deficienciesdeficiencies

www.diabetesinsider.com

RisksRisks

�� Teratogens:Teratogens:

–– ZincZinc

–– Valproic acidValproic acid–– Valproic acidValproic acid

–– MethotrexateMethotrexate

–– AmniopterinAmniopterin

www.kids4research.org

PrognosisPrognosis

�� Fetal demise occurs in Fetal demise occurs in up to 50% of casesup to 50% of cases

�� Death is imminent Death is imminent �� Death is imminent Death is imminent after birthafter birth

Prevention / PlanningPrevention / Planning

�� Genetic counselingGenetic counseling

�� Vitamin therapyVitamin therapy

�� Folic acid Folic acid �� Folic acid Folic acid

–– 1 to 2 months prior to 1 to 2 months prior to conceptionconception

–– During 1st trimesterDuring 1st trimester

http://www2.massgeneral.org/livingwithtsc/care/counseling.htm

ArticlesArticles

1.1. Familial exencephaly Familial exencephaly -- anencephaly anencephaly sequence and translocation. sequence and translocation.

2.2. Neonate with meroacrania: radiological Neonate with meroacrania: radiological findings and review of the literature.findings and review of the literature.findings and review of the literature.findings and review of the literature.

3.3. Anencephaly: pitfalls in pregnancy Anencephaly: pitfalls in pregnancy outcome and relevance of the prenatal outcome and relevance of the prenatal exam.exam.

Interview with Interview with David C. Shaver, M.D.David C. Shaver, M.D.

Main Points:Main Points:

�� “The incidence of anencephaly and “The incidence of anencephaly and all neural tube defects is all neural tube defects is decreasing, mainly because of folic decreasing, mainly because of folic acid supplementationacid supplementation.”

�� “Typically we talk about “Typically we talk about �� “Typically we talk about “Typically we talk about exencephaly or acrania as being, exencephaly or acrania as being, that there is some dysmorphic that there is some dysmorphic brain tissue, whereas anencephaly brain tissue, whereas anencephaly there’s no brain tissue above the there’s no brain tissue above the brainstem.”brainstem.”

�� “30 to 50“30 to 50--fold increase of the fold increase of the likelihood of having another baby likelihood of having another baby with a neural tube defectwith a neural tube defect.”

(D. Shaver, personal communication, November 19, 2010)

ReferencesReferences

�� Agamanolis, D.P. (2006). Congenital abnormalities of the CNS and hydrocephalus. Agamanolis, D.P. (2006). Congenital abnormalities of the CNS and hydrocephalus. Retrieved November 6, 2010, from Retrieved November 6, 2010, from http://neuropathology.neoucom.edu/chapter11/chapter11bNTD.htmlhttp://neuropathology.neoucom.edu/chapter11/chapter11bNTD.html

�� Anencephaly. (n.d.) Retrieved November 5,2010, from Anencephaly. (n.d.) Retrieved November 5,2010, from http://www.childrenshospital.org/az/Site578/mainpageS578P0.htmlhttp://www.childrenshospital.org/az/Site578/mainpageS578P0.html

�� HagenHagen--Ansert, S.L. (2006) Ansert, S.L. (2006) Textbook of Diagnostic UltrasonographyTextbook of Diagnostic Ultrasonography (6th ed.). St. (6th ed.). St. Louis: Mosby Elsevier.Louis: Mosby Elsevier.

�� Henningsen, C. (2004) Henningsen, C. (2004) Clinical Guide to UltrasonographyClinical Guide to Ultrasonography. St. Louis: Mosby Elsevier.. St. Louis: Mosby Elsevier.�� Poulose, T., Tsepov, D. & Fox, R. (2007). Familial exencephaly Poulose, T., Tsepov, D. & Fox, R. (2007). Familial exencephaly -- anencephaly anencephaly �� Poulose, T., Tsepov, D. & Fox, R. (2007). Familial exencephaly Poulose, T., Tsepov, D. & Fox, R. (2007). Familial exencephaly -- anencephaly anencephaly

sequence and translocation. sequence and translocation. Journal of Obstetrics & GynaecologyJournal of Obstetrics & Gynaecology, , 2727(3), 317(3), 317--318. doi:10.1080/01443610701241233. Retrieved November 8, 2010 from 318. doi:10.1080/01443610701241233. Retrieved November 8, 2010 from Health Source: Nursing/Academic Edition database Health Source: Nursing/Academic Edition database

�� Sanders, R.C., & Winter, T. (2007) Sanders, R.C., & Winter, T. (2007) Clinical Sonography A Practical GuideClinical Sonography A Practical Guide (4th ed.) (4th ed.) Philadelphia: Lippincott Williams & WilkinsPhiladelphia: Lippincott Williams & Wilkins

�� Tica, V.I., Beghim, M., Tica, I., Zaher, M. & Beghim, E. (2009). Anencephaly: pitfalls Tica, V.I., Beghim, M., Tica, I., Zaher, M. & Beghim, E. (2009). Anencephaly: pitfalls in pregnancy outcome and relevance of the prenatal exam. in pregnancy outcome and relevance of the prenatal exam. Romanian Journal Romanian Journal of Morphology and Embryologyof Morphology and Embryology, 50 (2). Retrieved November 8, 2010 from , 50 (2). Retrieved November 8, 2010 from Health Source: Nursing/Academic Edition database.Health Source: Nursing/Academic Edition database.

�� Yildirim, H., Koc, M., Nese, K., Hakan, A. & Denizmen, A. (2009). Neonate with Yildirim, H., Koc, M., Nese, K., Hakan, A. & Denizmen, A. (2009). Neonate with meroacrania: radiological findings and review of the literature. meroacrania: radiological findings and review of the literature. Diagnostic and Diagnostic and Interventional RadiologyInterventional Radiology, 15 (4). Retrieved November 8, 2010 from Health , 15 (4). Retrieved November 8, 2010 from Health Source: Nursing/Academic Edition database.Source: Nursing/Academic Edition database.

End of Presentation QuizEnd of Presentation Quiz

Which gender and race Which gender and race has a higher risk for has a higher risk for anencephaly?anencephaly?

A.A. Males, HispanicsMales, HispanicsMales, HispanicsMales, Hispanics

B.B. Females, WhitesFemales, Whites

C.C. Females, BlacksFemales, Blacks

D.D. Males, AsiansMales, Asians