Fetal Medicine. Case Presentations. Dr Ermos Nicolaou Fetal Medicine Unit Chris Hani Baragwanath Hospital. October 2003

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1 Case Presentations Dr Ermos Nicolaou Fetal Medicine Unit Chris Hani Baragwanath Hospital October 2003

2 Case 1 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

8 Case 1 Elective C/S performed; no complications Antenatal findings confirmed

12 Case 1 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

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

18 Case 2 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

21 Case 2 On scan: Anterior/ frontal encephalocele, lemon sign Nasal bone not visible Central ossification failure Rest of face appears normal No other abnormalities seen

22 Case 2 Counselling: 1. TOP 2. Conservative management with close monitoring? Patient absconded

23 These include NEURAL TUBE DEFECTS 1. Anencephaly 2. Spina bifida 3. 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

24 NEURAL TUBE DEFECTS In spina bifida the neural arch, usually in the lumbosacral region, is incomplete with secondary damage to the exposed nerves

25 NEURAL TUBE DEFECTS Prevalence 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%

26 NEURAL TUBE DEFECTS Etiology 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

27 NEURAL TUBE DEFECTS Anencephaly 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

28 NEURAL TUBE DEFECTS Anencephaly

29 NEURAL TUBE DEFECTS Spina bifida 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

30 NEURAL TUBE DEFECTS Spina bifida

31 NEURAL TUBE DEFECTS Spina bifida 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 1. frontal bone scalloping (lemon sign), 2. and obliteration of the cisterna magna 3. with either an "absent" cerebellum or abnormal anterior curvature of the cerebellar hemispheres (banana sign).

32 NEURAL TUBE DEFECTS Spina bifida

33 NEURAL TUBE DEFECTS Spina bifida

34 NEURAL TUBE DEFECTS Spina bifida 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

35 NEURAL TUBE DEFECTS Encephalocele 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

36 ENCEPHALOCELE - DEFINITION 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.

37 NEURAL TUBE DEFECTS Encephalocele

38 ENCEPHALOCELE - EPIDEMIOLOGY incidence: 1/10th as common as spinal neural tube defects risk factors: multifactorial inheritance pattern

39 ENCEPHALOCELE -associated anomalies 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

40 ENCEPHALOCELE -PATHOGENESIS 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 1. portions of the brain found in the herniated meningeal sac include cerebral cortex, cerebellum, brainstem, and/or ventricles 2. neural tissue within encephalocele is often abnormal 3. the amount of compromised and deformed neural tissue determines the extent of cerebral dysfunction 4. brain tissue not extending into the encephalocele may be structurally and functionally abnormal

41 Types of Encephaloceles 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

42 CLINICAL FEATURES 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 -> infection

43 CLINICAL FEATURES 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

44 INVESTIGATIONS 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

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

46 MANAGEMENT 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

47 Fetal therapy 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

48 NEURAL TUBE DEFECTS Prognosis 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

Central nervous system. Obstetrics Content Outline Obstetrics - Fetal Abnormalities

Central nervous system. Obstetrics Content Outline Obstetrics - Fetal Abnormalities Obstetrics Content Outline Obstetrics - Fetal Abnormalities Many congenital malformations of the CNS result from incomplete closure of the neural tube Effective February 2007 10 16% the most common neural