NEUROPATHOLOGY II.ppt
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NEUROPATHOLOGY II.ppt NEUROPATHOLOGY II.ppt Presentation Transcript

  • NEUROPATHOLOGY II
    • MALFORMATIONS OF THE CNS. DEFINITIONS. *Malformations -primary disturbance of embryonic or fetal development *Field defect *Disruption -secondary compromise of development due to vascular events, infections, etc.
  • NEUROPATHOLOGY II
    • DEFINITIONS.... *Deformation -external mechanical influences affect ing development *Dysplasia -abnormal neuronal clustering/localiza tion secondary to neuronal migrational defects
  • NEUROPATHOLOGY
    • Gestation Embryogenesis Effects 1st/2nd wk zygote  3germ lay. Death Cranioschisis 3rd-4th wk neural tube form.: Anencephaly Anterior pore clos. Rachischisis Posterior pore clos. Encephalocele Meningom. Spina bifida Arnold-Chiari Dandy-Walker
  • NEUROPATHOLOGY II
    • Gestation Embryogenesis Effects 5th-6th wk -develop.face/forebr.
    • -differentiat.prosence Faciotelence- phaly  olfact.tract, phalic malfor optic vesicles,telence mation phalon/diencephalon -cleavage of telencep. Holoprosen- into cerebral hemisp. cephaly
  • NEUROPATHOLOGY II
    • Gestation Embryogenesis Effects 6th wk-4th -neuronal/glial Microceph mo. prolif./migration Megalenc. (develop of brain Lissencep. cortex,meninges, Pachygyria ventricles,foram., Polymicro- circul. of CSF) gyria Heterotop.
  • NEUROPATHOLOGY II
    • Gestation Embryogenesis Effects 5th month -glial different. Porenceph. (astrocytes  nu- Hydranen- trition,oligodend. cephaly  myelination) -primary sulci appear
  • NEUROPATHOLOGY II
    • Gestation Embryogenesis Effects 6th month -neuronal organiz. Down´s and architectonic syndrome (dendritic/axonal Hypothyr. connections,syna Phenilket. psis formation,apo- ptosis, myelination) 7h-9th mos. -second.sulci appear
  • NEUROPATHOLOGY II
    • CAUSES OF MALFORMATIONS. *Chromosomal abnormalities -Trisomy 9, 13, 18, 21 - Deletions 4p, 17p -Gene mutations *Radiation *Viral infections -Herpes simplex/Varicella zoster -Cytomegalovirus -Rubella *Toxoplasmosis
  • NEUROPATHOLOGY II
    • CAUSES OF MALFORMATIONS... *Metabolic -Maternal Diabetes mellitus: Holoprosencephaly Sacral agenesis -Maternal phenylketonuria Microcephaly -Anticonvulsivants(phenytoin) Microcephaly 2x risk of mental retardation 1-2% risk of spina bifida(valproic acid) -Dietary deficiency(folic acid  neural tube defects)
  • NEUROPATHOLOGY II
    • CAUSES OF MALFORMATIONS... -Retinoic acid/Isotretinoin(retinoid)  Hydrocephalus, holoprosencephaly, microcephaly,abnormal cerebral/cere bellar cortical migration, cerebellar hypoplasia, agenesis of vermis,cerebellar microgenesis,heterotopia, focal agyria, calcification - -Warfarin  microcephaly, meningocele, Dandy-Walker malf.,agenesis of corpus callosum and diffuse cerebral atrophy
  • NEUROPATHOLOGY II
    • CAUSES OF MALFORMATIONS... *Alcohol -Fetal-alcohol syndrome 0.4-3.5/live births 190/1000 in some North American Indian pop.(genetic? poverty?) Neonatal mortality-5.8-17% Microcephaly,microphtalmia,mental re tardation,hyperactivity,motor problems Growth deficiency(often below 10th percentile)
  • NEUROPATHOLOGY II
    • CAUSES OF MALFORMATIONS...
    • *Cocaine -Myelomeningocele, encephalocele, agenesis of corpus callosum,hetero topias, schizencephaly, etc.
  • NEUROPATHOLOGY II
    • MAJOR GROUPS OF MALFORM....
    • *Neural tube closure defects
    • *Disorders of forebrain induction
    • *Neuronal migration defects
    • *Encephaloclstic defects
  • NEUROPATHOLOGY II
    • NEURAL TUBE DEFECTS(Dysraphic disorders) *Primary defects in closure of neuropore -Anencephaly -Craniorachischisis -Myelomeningocele *Primary bone defects(abnormality in axial mesoderm development) -Spina bifida occulta -Encephalocele -Meningocele
  • NEUROPATHOLOGY II
    • ANENCEPHALY
    • *Is the MOST common congenital malfor mation of the brain
    • *Known as far back as Egyptian antiquity
    • *Compared to the toad(Morgagni,1761)
    • *Geographic variation in incidence: -1-6 / 1000 in Ireland and Wales -0.5-2 / 1000 in US
  • NEUROPATHOLOGY II
    • ANENCEPHALY... *Etiology – unknown *Possible risk factors: -Geographic location -Socioeconomic factors -Diet  folic acid deficiency -Genetic  few familial cases observed *More common in females
  • NEUROPATHOLOGY II
    • ANENCEPHALY.... -Hypoplasia or absence of cranium -Shallow orbits with protrusion of eyes -Hypoplastic lungs -Large thymus -Abnormal pituitary(lack of hypothalamus/ neurohypophysis) -Other abnormalities: adrenal hypoplasia
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  • NEUROPATHOLOGY II
    • ANENCEPHALY.... -Associated craniorachischisis -Area cerebrovasculosa -Prenatal Dx: increased maternal serum/am niotic A-fetoprotein -Recurrence risk of 3-5%
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  • NEUROPATHOLOGY II
    • MYELOMENINGOCELE. *Herniation of both meninges/spinal cord through a large vertebral defect *Most often lumbosacral *Frequent association w/hydrocephalus -Arnold-Chiari malformation type II *Area medullovasculosa *Meningocele: herniation of meninges only *Occult spina bifida:mildest form of neural tube defect
  • NEUROPATHOLOGY II
    • SPINAL DYSRAPHISM(spina bifida). *It may be an asymptomatic bone defect (spina bifida occulta) *Also, it can be a severe malformation w/ flattened and disorganized segment of spinal cord associated to an outpouching of meninges
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  • NEUROPATHOLOGY II
    • ARNOLD-CHIARI MALFORMATION. There are 4 types: *Type I –cerebellar tonsillar herniation *Type II- malformation of craniobasal bone, shallow posterior fossa *Type III-occipito-cervical bony defect -occipital encephalocele -herniation of cerebellum into en cephalocele *Type IV-cerebellar hypoplasia
  • NEUROPATHOLOGY II
    • ARNOLD-CHIARI MALFORMATION... *TYPE II -Herniation of inferior cerebellar vermis -Elongation and downward displacement of medulla and cervical cord -Malformation of craniobasal bone, shallow posterior fossa
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  • NEUROPATHOLOGY II
    • ARNOLD-CHIARI MALFORMATION... *Associated hydrocephalus, meningomyelo cele, aqueductal stenosis or atresia, ventri cular neuronal heterotopia, microgyria, “beaking” of tectum *Craniolacunae – single or multiple translu cent thinning of cranium – dissapears at age of 1-2 yrs.
  • NEUROPATHOLOGY II
    • SYRINGOMYELIA. *About 90% of cases associated w/Arnold- Chiari type I malformation(tonsillar herniat.) *Wasting and weakness of hand and fore- arm muscles, dissociated anesthesia of upper limbs *Kyphoscoliosis or Charcot´s joints *Slowly progressive *Syringobulbia may be present
  • NEUROPATHOLOGY II
    • SYRINGOMYELIA.... *Characterized by formation of a fluid-filled cleft-like cavity in the inner cord *Lesion associated w/destruction of gray and white matter in the vacinity, surrounded by a dense reactive gliosis *The formed cavity may be extended from the cervical spinal cord upward into the brainstem
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  • NEUROPATHOLOGY II
    • NEURONAL MIGRATION DEFECTS.
    • *Cerebral cortical dysplasia.
    • (A) Status verrucosus
    • (B) Four layered cortex
    • (C) Irregular cord-like cortical dysplasia
  • NEUROPATHOLOGY II
    • NEURONAL MIGRATION...
    • *Cerebral cortical dyplasia...
    • -Lissencephaly(agyria)
    • -Pachygyria
    • smooth brain + 4 layered cortex
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  • NEUROPATHOLOGY II
    • NEURONAL MIGRATION.... *Cerebral cortical dysplasia...
    • -Miller-Dieker syndrome: Microencephaly
    • Seizures
    • Mental retardation
    • Furrowed forehead
    • Neonatal jaundice
    • Purpura
    • Deletion of L1S1 gene,chromosome 17p13.3(90% of patients)
  • NEUROPATHOLOGY II
    • NEURONAL MIGRATION....
    • *Cerebral cortical dysplasia...
    • -Polymicrogyria
    • Increased number of gyri w/ abnormal cytoarchitecture (4 layers of cortex)
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  • NEUROPATHOLOGY II
    • NEURONAL MIGRATION...
    • *Cerebral cortical dysplasia...
    • -Polymicrogyria...
    • Etiology:
    • Ischemia,infections(CMV, toxoplasma,varicella zoster,
    • syphilis)
    • Familial syndromes
    • Metabolic diseases(peroxisomal,
    • mitochondria encephalopathy,etc)
  • NEUROPATHOLOGY II
    • DISORDERS OF FOREBRAIN INDUCT. *Holoprosencephaly.
    • -Anomalies of prosencephalic outgrowth and cleavage
    • -Types – classified by degree of gyral de velopment:
    • Alobar
    • Semilobar
    • Lobar
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  • NEUROPATHOLOGY II
    • DISORDERS OF FOREBRAIN INDUCT... *Holoprosencephaly....
    • -Varying grades of facial dysmorphim: “the face predicts the brain” -Other systemic malformations are freq. -Mild form of these is known as arrhinen cephaly w/lack of development of the olfactory bulb and tract
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  • NEUROPATHOLOGY II
    • DISORDERS OF FOREBRAIN INDUCT... *Holoprosencephaly....
    • -Incidence: 1/16,000-1/31,000
    • -M:F = 1:3
    • -Chromosomal abnormalities
    • Trisomy 13(most common), 18, etc
    • Familial: AR or AD or X-linked R
    • Maternal diabetes
    • Maternal infections:toxoplasma,rubella
    • Fetal-alcohol syndrome
  • NEUROPATHOLOGY II
    • ENCEPHALOCLASTIC DEFECTS.
    • *Porencephaly
    • -Defects in the wall of the cerebral he misphere with communication between ventricle and the surface
    • -”Basket brain”(Schizencephaly) w/seve re bilateral hemispheric porencephalic
    • defects  smooth walled and surrounded by gyral pattern
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  • NEUROPATHOLOGY II
    • ENCEPHALOCLASTIC DEFECTS.....
    • *Porencephaly...
    • Clinical:
    • -Spasticity
    • -Seizures
    • -Severe mental retardation
    • -Blindness
    • -Survival into adult life in some patients
    • *Other associated anomalies
  • NEUROPATHOLOGY II
    • “ Basket brain”(Schizencephaly) *Etiology – unknown -Presumably destructive events occurring early during fetal life
    • -Events antedate the acquisition of mature astroglial response or completion of convo- lutional development
    • -Vascular insults, infections, trauma, etc.
  • NEUROPATHOLOGY II
    • ENCEPHALOCLASTIC DEFECTS... *Hydranencephaly. -Etiology:
    • Vascular events
    • Maternal infections-CMV,toxoplasm Trauma
    • -Clinical feature:
    • Seizures,spascity,poor psychomotor development
    • Survival is short but can be up to 1 yr or longer
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  • NEUROPATHOLOGY II
    • ENCEP-HALOCLASTIC DEFECTS...
    • *Agenesis of corpus callosum.
    • -Relatively a common malformation(1 in 19,000 autopsies and 2.3% in chil dren w/mental retardation)
    • -Defect that can be partial or complete
    • -May present seizures, intellectual im- pairment, psychosis(due mostly to other
    • associated anomalies)
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  • NEUROPATHOLOGY II
    • ENCEPHALOCLASTIC DEFECTS....
    • *Multicystic encephalomalacia.
    • Encephloclastic mechanism as in porencephaly and hydranencephaly
    • -Mainly related to vascular events ocurring in the third trimester or perinatal life
    • -Severe forms are due to global hemispheric necrosis -May also follow viral infections
  • NEUROPATHOLOGY II
    • ENCEPHALOCLASTIC DEFECTS...
    • *Multicystic encephalomalacia...
    • -Are cavities ragged and irregular without cortical malformations
    • -Gliosis and lipid laden macrophages are his tological characteristics