Fetal Medicine Case Presentations Dr Ermos Nicolaou Fetal

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Case Presentations
Fetal Medicine

• Dr Ermos Nicolaou
• Fetal Medicine Unit
• Chris Hani Baragwanath Hospital

October 2003
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Case 1
Fetal Medicine

• Ms A M
• 22year old P0 G1
• Referred from Sebokeng Hospital at 36w for
  polyhydramnios
• On Ultrasound
• Mild/Moderate ventriculomegaly
• Large cystic mass arisisng from the posterior
  aspect of the fetal
• skull 120x 170mm in diameter
• No other abnormalities seen
• Dx Large Meningocele
• Plan In view of the advanced gestational age no
  inetrvention justifiable
• Elective C/S at 38w and post natal assessment

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Case 1
Fetal Medicine

• Elective C/S performed no complications
• Antenatal findings confirmed

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Case 1
Fetal Medicine

• Baby admitted to neuro-surgical ward
• Neurological assessment normal at this point
• CT scan Occipital meningocele
• No brain tissue involved
• Moderate dilatation of the ventricles

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Case 1
Fetal Medicine

• Surgery performed on day 9 post delivery
• Uneventful procedure
• Baby discharged on day 4
• For follow up in 1 week

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Case 2
Fetal Medicine

• Mrs N N
• 32 year old P0 G1
• Had normal NT at 12 weeks
• Presents at 20 w 2d with a central supra-ocular
  mass

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Case 2
Fetal Medicine

• On scan
• Anterior/ frontal encephalocele, lemon sign
• Nasal bone not visible
• Central ossification failure
• Rest of face appears normal
• No other abnormalities seen

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Case 2
Fetal Medicine

• Counselling
• TOP
• Conservative management with close monitoring
• ? Patient absconded

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NEURAL TUBE DEFECTS
Fetal Medicine

• These include
• Anencephaly
• Spina bifida
• Encephalocoele
• In anencephaly there is absence of the cranial
  vault  (acrania) with secondary degeneration of
  the brain
• Encephaloceles are cranial defects, usually
  occipital, with herniated fluid-filled or
  brain-filled cysts

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NEURAL TUBE DEFECTS
Fetal Medicine

• In spina bifida the neural arch, usually in the
  lumbosacral region, is incomplete with secondary
  damage to the exposed nerves

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NEURAL TUBE DEFECTS Prevalence
Fetal Medicine

• Subject to large geographical and temporal
  variations
• In the UK the prevalence is about 5 per 1,000
  births
• Anencephaly and spina bifida, with an
  approximately equal
• prevalence, account for 95 of the cases and
  encephalocele for
• the remaining 5

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NEURAL TUBE DEFECTSEtiology
Fetal Medicine

• Chromosomal abnormalities, single mutant genes,
  and maternal
• diabetes mellitus or ingestion of teratogens,
  such as antiepileptic
• drugs, are implicated in about 10 of the cases
• precise etiology for the majority of these
  defects is unknown
• When a parent or previous sibling has had a
  neural tube defect,
• the risk of recurrence is 5-10. Periconceptual
  supplementation of
• the maternal diet with folate reduces by about
  half the risk of
• developing these defects

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NEURAL TUBE DEFECTSAnencephaly
Fetal Medicine

• Diagnosis of anencephaly during the second
  trimester of
• pregnancy is based on the demonstration of absent
  cranial vault
• and cerebral hemispheres
• Associated spinal lesions are found in up to 50
  of cases
• In the first trimester the diagnosis can be made
  after 11 weeks, when ossification of the skull
  normally occurs

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NEURAL TUBE DEFECTSAnencephaly
Fetal Medicine
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NEURAL TUBE DEFECTSSpina bifida
Fetal Medicine

• Diagnosis of spina bifida requires the systematic
  examination of
• each neural arch from the cervical to the sacral
  region both
• transversely and longitudinally
• In the transverse scan the normal neural arch
  appears as a
• closed circle with an intact skin covering,
  whereas in spina bifida
• the arch is "U" shaped and there is an associated
  bulging
• meningocoele (thin-walled cyst) or
  myelomeningocoele

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NEURAL TUBE DEFECTSSpina bifida
Fetal Medicine
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NEURAL TUBE DEFECTSSpina bifida
Fetal Medicine

• The diagnosis of spina bifida has been greatly
  enhanced by the
• recognition of associated abnormalities in the
  skull and brain
• Secondary to the Arnold-Chiari malformation and 
  include
• frontal bone scalloping (lemon sign),
• and obliteration of the cisterna magna
• with either an "absent" cerebellum or abnormal
  anterior
• curvature of the cerebellar hemispheres (banana
  sign).

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NEURAL TUBE DEFECTSSpina bifida
Fetal Medicine
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NEURAL TUBE DEFECTSSpina bifida
Fetal Medicine
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NEURAL TUBE DEFECTSSpina bifida
Fetal Medicine

• A variable degree of ventricular enlargement is
  present in
• virtually all cases of open spina bifida at
  birth, but in only about
• 70 of cases in the midtrimester

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NEURAL TUBE DEFECTSEncephalocele
Fetal Medicine

• Encephaloceles are recognised as cranial defects
  with herniated
• fluid-filled or brain-filled cysts
• most commonly found in an occipital location (75
  of the cases)
• but alternative sites include the
  frontoethmoidal and parietal
• regions

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ENCEPHALOCELE - DEFINITION
Fetal Medicine

• A neural tube defect affecting the skull
  resulting in the
• herniation of the meninges and portions of the
  brain through a
• bony midline defect in the skull.

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NEURAL TUBE DEFECTSEncephalocele
Fetal Medicine
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ENCEPHALOCELE - EPIDEMIOLOGY
Fetal Medicine

• incidence 1/10th as common as spinal neural tube
  defects
• risk factors
• multifactorial inheritance pattern

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ENCEPHALOCELE -associated anomalies
Fetal Medicine

• 1. Syndromes
• Dandy-Walker Syndrome
• Klippel-Feil Syndrome
• Meckel-Gruber Syndrome
• rare autosomal recessive disorder
• occipital encephalocele
• associated with microcephaly, holoprosencephaly,
  cleft lip or palate, polydactyly, abnormal
  genitalia, polycystic kidneys
• 2. Malformations
• Arnold-Chiari malformation, porencephaly,
  agenesis of the corpus callosum, myelodysplasia,
  optic nerve dysplasia, cleft palate

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ENCEPHALOCELE -PATHOGENESIS
Fetal Medicine

• Background
• two major forms of dysraphism affecting the
  skull
• 1. Cranial Meningocele
• consists of a CSF-filled meningeal sac only
• skull equivalent of a spinal meningocele
• 2. Cranial Encephalocele
• portions of the brain found in the herniated
  meningeal sac
• include cerebral cortex, cerebellum, brainstem,
  and/or ventricles
• neural tissue within encephalocele is often
  abnormal
• the amount of compromised and deformed neural
  tissue
• determines the extent of cerebral dysfunction
• brain tissue not extending into the encephalocele
  may be
• structurally and functionally abnormal

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Types of Encephaloceles
Fetal Medicine

• 1. Notencephaloceles (75)
• extend from the occipital region at or below the
  inion
• 2. Sincipital Encephaloceles (25)
• extend from the orbits, nose or forehead
• occur most frequently in Asians
• basal and transsphenoid encephaloceles
• rare, arise between the ethmoid and sphenoid
  bones and may present as an intranasal mass
• may extend into the upper pharynx
• neuroendocrine disturbances if the encephalocele
• involves the sella turcica or sphenoid sinus

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CLINICAL FEATURES
Fetal Medicine

• 1. Encephalocele
• hernia may be a small CSF-filled meningeal sac or
  a large
• cyst-like structure that may exceed the size of
  the head
• may be covered with skin and/or membrane of
  varying
• thickness - transillumination
• - may show presence of neural tissue
• - may be pulsatile
• - covering may infarct and rupture -gt infection

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CLINICAL FEATURES
Fetal Medicine

• 2. Complications (Neural)
• Arnold-Chiari Malformation - Type 3
• an occipital encephalocele with a spina bifida
  over the
• cervical area with protrusion of the cerebellum
  through
• this opening
• may be associated with hydrocephalus
• Developmental delay
• i.e., motor with weakness and/or spasticity,
  ataxia
• mental retardation
• microcephaly
• seizures
• visual problems
• with occipital lobe involvement

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INVESTIGATIONS
Fetal Medicine

• Imaging Studies
• 1. Ultrasound
• will determine the contents of the encephalocele
• can detect encephaloceles in utero
• 2. CT/MRI
• herniated brain tissue with a bony defect in the
  skull

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Prenatal Diagnosis
Fetal Medicine

• elevated maternal serum alpha-feto-protein (AFP)
• level II ultrasound
• amniocentesis - elevated AFP and
  acetylcholinesterase

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MANAGEMENT
Fetal Medicine

• 1. Surgery
• correction is ineffective if the sac contains a
  significant
• amount of brain tissue
• shunting required if hydrocephalus
• 2. Supportive
• for complications
• physiotherapy
• anticonvulsants
• ophthalmology follow-up

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Fetal therapy
Fetal Medicine

• There is some experimental evidence that in-utero
  closure of
• spina bifida may reduce the risk of handicap
  because the amniotic
• fluid in the third trimester is thought to be
  neurotoxic

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NEURAL TUBE DEFECTSPrognosis
Fetal Medicine

• Anencephaly is fatal at or within hours of birth
• In encephalocoele the prognosis is inversely
  related to the
• amount of herniated cerebral tissue
• overall the neonatal mortality is about 40 and
  more that 80
• of survivors are intellectually and
  neurologically handicapped
• In spina bifida the surviving infants are often
  severely
• handicapped, with paralysis in the lower limbs
  and double
• incontinence
• despite the associated hydrocephalus requiring
  surgery, intelligence may be normal

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