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Differential Diagnosis of Nervous System Disorders

  1. DORSAL INDUCTION ANOMALY
    = defects of neural tube closure
    1. Anencephaly
    2. Cephalocele at 4 weeks
    3. Chiari malformation at 4 weeks
    4. Spinal dysraphism
    5. Hydromyelia
  2. VENTRAL INDUCTION ANOMALY
    = defects in formation of brain vesicles + face
    1. Holoprosencephaly: 5–6 weeks
    2. Septo-optic dysplasia: 6–7 weeks
    3. Dandy-Walker malformation: 7–10 weeks
    4. Agenesis of septum pellucidum
  3. NEURONAL PROLIFERATION & HISTOGENESIS
    1. Neurofibromatosis: 5 weeks–6 months
    2. Tuberous sclerosis: 5 weeks–6 months
    3. Primary hydranencephaly: >3 months
    4. Neoplasia
    5. Vascular malformation (vein of Galen, AVM, hemangioma)
  4. NEURONAL MIGRATION ANOMALY
    due to infection, ischemia, metabolic disorders
    1. Schizencephaly: 2 months
    2. Agyria + pachygyria: 3 months
    3. Gray matter heterotopia: 5 months
    4. Dysgenesis of corpus callosum: 2–5 months
    5. Lissencephaly
    6. Polymicrogyria
    7. Unilateral megalencephaly
  5. DESTRUCTIVE LESION
    1. Hydranencephaly
    2. Porencephaly
    3. Hypoxia: periventricular leukomalacia, germinal matrix hemorrhage
    4. Toxicosis
    5. Infections (TORCH)
      1. Toxoplasmosis
      2. Other: syphilis, hepatitis, zoster
      3. Rubella
        • punctate / nodular calcifications
        • porencephalic cysts
        • occasionally microcephaly
      4. Cytomegalovirus inclusion disease
        • typically punctate / stippled / curvilinear periventricular calcifications
        • often hydrocephalus
      5. Herpes simplex

Absence of Septum Pellucidum!!navigator!!

  1. Holoprosencephaly
  2. Callosal agenesis
  3. Septo-optic dysplasia
  4. Schizencephaly
  5. Severe chronic hydrocephalus
  6. Destructive porencephaly

Phakomatoses!!navigator!!

[phako, Greek = lens / lentil-shaped object]

= NEUROCUTANEOUS SYNDROMES = NEUROECTODERMAL DYSPLASIAS

= development of benign tumors / malformations in organs of ectodermal origin (CNS, eye, skin)

  1. autosomal dominant:
    1. Neurofibromatosis (von Recklinghausen)
    2. Tuberous sclerosis (Bourneville)
    3. Retinocerebellar hemangioblastoma (Von Hippel-Lindau)
    4. Neurocutaneous melanosis
  2. not autosomal dominant:
    1. Encephalotrigeminal angiomatosis (Sturge-Weber-Dimitri)
    2. Ataxia-telangiectasia

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