Malformations Of CNS

Question 1

Occult spinal dysraphism

Answer 1

Spina bifocals occulta with neurologic involvement

Tethered cord

Weakness, spasticity, sensory loss in legs, gait abn, foot deformity, Bowel/bladder dysfunction

Question 2

Meningocele

Answer 2

Protrusion of meninges, without nervous tissue, not associated with neurologic deficit

Can be associated with aqueductal stenosis, hydromyelia, chiari malformations

Question 3

Myelomeningocele

Answer 3

May have complete exposure of neural elements, or may be covered with membrane

Involvement of cord, roots, meninges, vertebral bodies and skin

Lumbosacral most common

Hydrocephalus is common comorbidity with chiari II malformation
Thoracolumbar region

Question 4

Maternal alpha-fetoprotein

Answer 4

Measurement used to identify fetus with or at risk for neural tube defects

Question 5

Diastematomyelia

Answer 5

Midline septum divides cord into 2 portions

Each cord can be in same arachnoid/Dural sleeve or their own

Present with congenital scoliosis, hydrocephalus, cutaneous lesions

Question 6

Diplomyelia

Answer 6

Side by side or ant/post duplication of cord, each section has own central canal

Deterioration suggest either diastematomyelia or tethering

Question 7

Sacral agenesis

Answer 7

Congenital absence of whole or part of sacrum

Moms with insulin dep diabetes

ASP syndrome localized to 7q36, mutations to HLXB9

Question 8

Chiari type I️

Answer 8

Downward displacement of cerebellum and cerebellar tonsils, elongated brain stem/4th ventricle

Question 9

Chiari Type II

Answer 9

Downward displacement of tonsils and vermis, elongated medulla, seen in pts with myelomeningocele

Question 10

Chiari Type III

Answer 10

Encephalocervical meningocele and protrusion of cerebellum through post encephalocele

Question 11

Chiari Type IV

Answer 11

Hypoplasia of cerebellum

Question 12

Encephalocele

Answer 12

Herniation of cranial contents through midline skull defect

Include brain parenchyma

Folic avid not protective

Microcephaly, severe delay

Question 13

Anencephaly

Answer 13

Congenital malformation where both cerebral hemispheres are absent

Question 14

Schizencephaly

Answer 14

Gray matter cleft that extends from lateral ventricle to inner table of skull

Open or closed lip

Bilateral often associated with mental retardation and spasticity, unilateral frequently associated with epilepsy

Question 15

Septum pellucidum abnormalities

Answer 15

Absence of septum pellucidum frequently associated with septooptic dysplasia, agenesis of corpus callous, schizencephaly, hydrocephalus Or encephalocele

Question 16

Agenesis of corpus callous

Answer 16

Partial can be thinning of entire structure or absence of caudal portion (rostral retained unless complete agenesis)

Can be associated with chiari Type II

Question 17

Septo optic dysplasia

Answer 17

De morsier’s syndrome
Optic nerve hypoplasia, midline neuroradiologic abnormalities like absence of septum pellucidum or agenesis of corpus callosum, and hypothalamic/pituitary hypoplasia with associated pituitary hormone deficiencies

Question 18

Chiari I️

Answer 18

Leading cause of syringomyelia

HA, pseudo tumor like episodes, lower cranial nerve signs, Meniere’s like syndrome, spinal cord disturbances

Sleep apnea, dysarthria, dysphagia

Question 19

Cerebellar hypoplasia

Answer 19

Speech delay, autistic features, ataxia, hypotonia, ocular signs

Question 20

Dandy walker

Answer 20

Hypoplasia of the vermis and dilatation of 4th ventricle

4the ventricle communicates with retro cerebellar cyst that will enlarge posterior fossa and elevate tentorium

Can be associated with communicating hydrocephalus

Associated malformations: occipital encephalocele, polymicrogyria, hetertopias

Question 21

Holoprosencephaly

Answer 21

Failure of complete separation of the prosencephalon into distinct cerebral hemispheres and also separation of telencephalon from diencephalon

Question 22

Semilobar holoprosencephaly

Answer 22

Anterior hemispheres not separated

Splenium of corpus callosum is present

Frontal horns of lateral ventricles not developed but posterior horns are

Question 23

Lobar holoprosencephaly

Answer 23

Lack of separation of most rostral and ventral components of hemispheres

Splenium and body of corpus callosum present but genu absent

Rudimentary frontal horns may be present

Question 24

Middle hemispheric variant

Answer 24

Mid portion of cerebellar hemispheres is continuous, with absence of corpus callosum in this region, but separation of ant frontal lobes, basal forebrain and occipital lobes

Question 25

Clinical characteristics of holoprosencephaly

Answer 25

Cyclops is
Proboscis
Hypotelorism
Median cleft lip and palatsingle central incisor

Endocrine problems are common

Question 26

Megalencephaly

Answer 26

Anatomic without extraneural malformations

Metabolic- lysosomal diseases, mucopolysaccharidoses, Tay Sachs, gangliosidoses

With gigantism- beckwith wiedmann syndrome, Soto’s, pituitary

With skeletal dysplasia- achrondroplasia, Apert’s

Spongy defeneration- Canavans and Alexander’s

Question 27

Hemimegalencephaly

Answer 27

Enlargement of one side of brain with associated gyral malformations, cortical thickening with lack of lamination, blurred gray-white boundaries, abnormal cell types

Posterior quadrant

Seizures

Question 28

Focal cortical dysplasia

Answer 28

Most common cause of medically intractable focal onset epilepsy

Question 29

Malformations of neuronal migration

Answer 29

Lissencephaly

• agyria
• pachygyria
• subcortical band hetertopia

Cobblestone complex malformation

Heterotopias

Question 30

Lissencephaly

Answer 30

Thick cortex

Ventricles enlargassociated with LIS1, DCX, ARX

Question 31

Subcortical band heterotopia

Answer 31

Most common cause is DCX gene

Usually in females due to X inactivation

Question 32

Cobblestone complex lissencephaly

Answer 32

Fukuyamas congenital muscular dystrophy

Muscle brain eye disease

Walker Warburg syndrome

Enlarged ventricles, abnormal white matter, small brain stem, small dysplastic cerebellum

Question 33

Neuronal heterotopias

Answer 33

Groups of neurons in inappropriate location

Most common in periventricular nodular heterotopias

X linked PNH due to mutation in filamin A gene

Question 34

Polymicrogyria

Answer 34

Abnormal cortical lamination, excessive cortical unfolding resulting in many small gyri with shallow sulci

Question 35

Schizencephaly

Answer 35

Gray matter lined cleft from pial surface to ventricle

Often associated with polymicrogyria at cortical surface

Question 36

Perisylvian polymicrogyria

Answer 36

Prominent pseudobulbar paresis (swallowing difficulties, aspiration) inability to protrude tongue, dysarthria, facial diplagia