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Septo-Optic Dysplasia Tim Alves

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Septo-Optic Dysplasia Tim Alves Outline Overview Etiology Epidemiology Presentation Workup Radiologic findings Prognosis and Treatment Key Points References Septo ... – PowerPoint PPT presentation

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Title: Septo-Optic Dysplasia Tim Alves


1
Septo-Optic DysplasiaTim Alves
2
Outline
  • Overview
  • Etiology
  • Epidemiology
  • Presentation
  • Workup
  • Radiologic findings
  • Prognosis and Treatment
  • Key Points
  • References

3
Septo-optic dysplasia
  • Previously called De Morsier syndrome
  • Originally described in 1941 as an absence of the
    septum pellucidum with optic nerve abnormalities.
  • Later updated to include pituitary dysfunction
  • There is some controversy regarding diagnostic
    criteria, but generally it is a clinical
    diagnosis made when at least 2 of 3 classic
    criteria are met
  • Optic nerve hypoplasia
  • Pituitary hormone abnormalities
  • Midline brain defects, including agenesis of the
    septum pellucidum and/or corpus callosum

4
Etiology
  • Early forebrain developmental abnormality
  • Disorder of midline ventral prosencephalic
    development (4th to 6th week of gestation)
    including optic nerves, forebrain, olfactory
    bulbs, septum pellucidum, corpus callosum, and
    pituitary gland
  • Most cases sporadic/idiopathic

5
Etiology, cont.
  • Genetic basis?
  • AD and AR patterns have been described, two genes
    identified HESX1 and SOX2
  • Genetic diagnosis made in lt1 of cases
  • Environmental?
  • Associated with maternal diabetes, quinidine
    ingestion, antiseizure medications, drug abuse,
    CMV infection, and congenital brain malformations
  • Multifactorial

6
Epidemiology
  • 1 in 10,000 to 1 in 50,000
  • More common in children born to younger mothers
    and first-borns
  • MF, no ethnic predilection

7
Uncertain classification
  • Heterogeneous, variable features and severity
  • Syndrome vs. complex
  • Continuum
  • Milder form of lobar holoprosencephaly?
  • Milder forms of SOD?

8
Presentation
  • Generally two presentations
  • At birth, in association with multiple congenital
    anomalies seizures, apnea, cyanosis, hypotonia,
    jaundice, microphallus
  • Later on in childhood, with growth failure and/or
    visual abnormalities
  • Approx. 50 do not have a schizencephaly this
    group tends to present with endocrine dysfunction
  • Approx. 50 of patients with SOD have a
    schizencephaly and present with seizures, almost
    normal visual apparatus, generally normal
    endocrine function SOD plus

9
Associated Clinical Findings
  • Developmental delay
  • Seizures
  • Visual impairment
  • Sleep disturbances
  • Precocious puberty
  • Obesity
  • Anosmia
  • SNHL
  • Cardiac anomalies

10
Diagnostic Workup
  • History visual problems, symptoms of hormonal
    deficiencies, other congenital and developmental
    abnormalities
  • Opthalmologic exam optic nerve hypoplasia
  • Tests of pituitary function
  • MR is the best imaging modality

11
MRI Findings in SOD
  • Optic nerve hypoplasia/dysplasia, unilateral or
    bilateral
  • Agenesis of the septum pellucidum
  • Abnormalities of the corpus callosum and
    hypothalamo-pituitary axis
  • Thin pituitary stalk, small anterior pituitary,
    posterior pituitary ectopia
  • Findings are variable, and also include
  • Olfactory nerve hypoplasia, schizencephaly,
    cortical dysplasias and heterotopia.

12
MR shows absent septum pellucidum, typical flat
ventricular roof, pointy frontal horns, absent
pituitary stalk and ectopic posterior lobe.
13
Images show absent septum pellucidum, hypoplastic
pituitary stalk and calloso-forniceal
continuation.
14
Significantly hypoplastic right optic nerve,
ipsilateral to close lip schizencephaly is
probably not SOD.
15
The optic nerves are very small as is the optic
chiasm and pituitary stalk, the septum pellucidum
is absent.
16
Imaging Differential Diagnosis
  • Lobar holoprosencephaly similar to SOD but has
    lack of separation (fusion) of cerebral
    hemispheres, SOD is considered by some to be a
    milder form of this disorder
  • Overlap syndromes Optic-infundibular dysplasia
    (OID) - normal septum Schizencephaly
  • Isolated ectopic posterior pituitary lobe normal
    optic chiasm/nerves, normal septum
  • Kallmann Syndrome- absent or dysplastic olfactory
    nerves/ olfactory sulci, hypogonadotropic
    hypogonadism, occasionally associated with
    visual, septal, or pituitary abnormalities

17
Prognosis and Treatment
  • Variable morbidity and prognosis - depends on
    associated brain and pituitary malformations
  • Possible hypothalamic and pituitary crises
    sudden death from hypocortisolism
  • Treatment Hormone replacement therapy

18
Key points
  • Classically optic nerve hypoplasia, pituitary
    hormone abnormalities, and absent septum
    pellucidum
  • Disorder of early prosencephalic development with
    varying presentations and degrees of severity
  • Mainly a clinical diagnosis
  • Exact criteria and classification is debatable
  • Continuum?
  • Majority of cases are idiopathic/sporadic, but
    genetic and environmental causes have been
    identified
  • MRI of the brain plays a key role in diagnosis
  • Key findings
  • Quickly narrows down a broad clinical
    differential diagnosis

19
References
  • Adam, A. Grainger Allisons Diagnostic
    Radiology, 5th ed. 2008. Ch 70, Malformations of
    commissural and related structures Figure 70.11
  • Barkovich AJ. Diagnostic Imaging Pediatric
    Neuroradiology, 1st edition, 2007. Amirsys. I5
    10-13.
  • Castillo M. Neuroradiology Companion Methods,
    Guidelines, and Imaging Fundamentals, 3rd ed.
    2006. p212-213.
  • Hahn JS and Barnes PD. Neuroimaging advances in
    holoprosencephaly Refining the spectrum of the
    midline malformation. Am J Med Genet C Semin Med
    Genet. 2010 Feb 15154C(1)120-32.
  • Webb EA, Dattani MT. Septo-optic dysplasia.
    European Journal of Human Genetics. 2010
    18393-397.
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