Pediatrics Neuro Flashcards
Baby brain signal differences
Opposite adult pattern because myelin high water content (adult=cholesterol, glycolipids). T1 at age 1, T2 at age 2.
Most idea signal to assess myelination in kids?
T1 before age 1, T2 after.
Order and timing of brain myelination
- brainstem, pst limb internal capsule myelinated at birth.
- Back to front, inf to sup (OC at 12 mo –> FL at 18mo)
- subcortical FTP at 40 mo
Changes in signal of pituitary, globes pallidus, and bone marrow
- Pit = T1 & T2 bright (ant –> iso at 2 mo, pst T2 hypo)
- GP=darker (Fe incr)
- Bmarr (active T1 Hypo –> fatty T1 hyper)
order of sinus development
- MESF, complete by 15 yrs
- ME present at birth, visible by 5mo/1yr (respectively)
- FS (~5 yrs on CT)
*I (ME) can Smell Finally!
colpocephaly-what is it, ass?
asymmetric dilation of occipital horns
- Colpocephaly is a congenital brain abnormality in which the occipital horns - the posterior or rear portion of the lateral ventricles (cavities) of the brain – are larger than normal because white matter in the posterior cerebrum has failed to develop or thicken.
- cc genesis, colocephaly, pericallosal lipoma
order of corpus callous formation
Front to back –> rostrum
CC parts (Good Bodies In utero Start Right)
Rostrum under. Genu, body, isthmus, splenium.
Probst bundles
WM tracts destined to cross the CC
Probst bundles or longitudinal callosal fascicles denote white matter fibers normally destined to cross the corpus callosum that instead parallel the interhemispheric fissure in patients with agenesis of the corpus callosum. These lead to widely spaced lateral ventricles forming the characteristic racing car sign.
CC agenesis findings
- abscent cc
- widely spaced lateral ventricles (steer horn, vertical ventricles)
- many other associations (MC anomaly seen with other cos malformation?), MC= lipoma.
MC locs intracranial lipomas ass with cc agenesis
inter hemispheric (50%), quad cistern (25%)
Iniencephaly
- deficient occipital bone with defect in the cervical region. (Inien=back of head/neck)
- star gazing
Inien
Back of head/neck
True or false-hindbrain preserved in anencephaly
True
what’s the most common location encephalocele and most classic association
occipital. Chiari III
Rhombencephalosynapsis-what is it, features, classic imaging, associations
- Absent Vermis –> abN fusion cerebellum.
- Rounded fastigial point, absent primary fissure, small 4th Vt, aqueduct stenosis–> hydrocephalus
- classic image: transversely oriented/continuity of single-lobed cerebellum
- association=holoprosencephaly, aqueductal stenosis
Joubert Syndrome-path, features, classic imaging, associations
- AR ciliopathy –> hindbrain malformation –> dysgen rotated vermis/small cerebellum –> MOLAR TOOTH
- large 4th vt, absent fastigial point and primary fissure, absent pyramidal decussation
- Ass- retinal dysplasia (50%), MCDK (30%), liver fibrosis (COACH)
molar tooth
dysgenesis of bs isthmus –> elongation pontomesencephalic junction –> deepening of interpeduncular fossa –> thick, straight, Long superior cerebellar peduncles
3 consistent findings of “Classic Dandy Walker”
Triad:
1) Vermis hypoplasia (usually inf pt). Cerebellar hemispheres displaced anterolateral (shape/volume maintained). Vermis upward rotation
2) torcular lamboid inversion (2/2 elevated tentorium.)
3) dilated 4th Vt
buzzword “torcular lamboid inversion”
what is the lambdoid and torcula?
Classic DW
- torcula-confluence of sinuses
- lamboid- BL sutures connecting parietal and occipital bones
What defines and comprises the Dandy-Walker continuum?
- Group of pst fossa malformations. In order of severity:
1) classic DWM
2) Vermian hypoplasia (VH)
3) Blake pouch (BP) remnant/cyst
4) Mega Cisterna magna (MCM)
manifestation classic DW
- OB screen
- intracranial P, macrocephaly (1mo)
classic DW associations
- hydrocephalus (90%)
- CNS malformations (~40%)- cc agen, encephalocele, heterotopia, polymicrogyria, etc.
vermis hypoplasia/variant DWM
- small/hypoplastic vermis with dilation of 4th Vt.
- vermis superiorly rotated, no torcular lamboid inversion
- Hydro (+) (25%)
Blake pouch
- sac like cystic protrusion through foramen of magendie into infra/retro cerebellar region
- cyst communicates with 4th Vt –> upward rotation of vermis, displacement 4th Vt choroid plexus in its superolateral margin (choroid swinging into pouch is classic.)
- Cyst communicate with 4th Vt, not cistern magna.
- dilated 4th vt, hydro (+)
- enlarged tegmentovermian angle (usually 0˚)–> “open 4th vt”
mega cisterna magna
- focal enlargement retrocerebellar css space
- no hydro
Holoprosencephaly (HPE). Forms.
- failure of midline cleavage
- back –> front
- forms (increasing sev):
4) Arhinencephaly
5) Septo Optic Dysplasia/de Morsier Syndrome
1) lobar
2) semi-lobar
3) alobar
lobar holoprosencephaly
anterior aspect variably not cleaved. Absent septum pellucid and partial/normal cc. Normal thalamus
semi-lobar holoprocencephaly
- > 50% frontal lobes fused
- thalamus fused (partial/complete). occ/temporal horns partially dev.
- cleft lip/palat
alobar holoncephaly
- No midline cleavage
- single Vt.
- cyclops monster face
- monster cyclops eyes
- clef lips/palates
- pyriform aperture stenosis (forum nasal process overgrowth)
- solitary median maxillary incisor (mega-incisor)
buzzwords for HPE spectrum
Arhinencephaly. What is it. Buzzword. Ass.
- minor HPE expression
- midline olfactory bulbs/tracts abscent
- “can’t smell”
- Kallmann syndrome (+ hypogonadism, mental retardation.)
buzzword: can’t smell
arhinencephaly
Meckel-Gruber Syndrome triad. Strong ass?
- triad: 1) occipital encephaloceles 2) multiple renal cysts 3) polydactyly
- strong ass= holoprosencephaly
Septo Optic Dysplasia-AKA. What is it? Strong ass?
-AKA De Morsier syndrome
- minor HPE expression.
- Absent septum pellucidum + hypoplastic optic structure (optic chiasm, optic nerves are tiny)
- hypothalamic-pituitary axis abN
-strong ass=schizencephaly
Azygos anterior cerebral artery
common trunk of ACA ass w/ SOD and lobar HPE
proliferative neuroepithelium
-neuronal-glial stem cells org in periVt region. Proliferate symmetrically –> asymm.
Brain proliferation
- symm (1 sc –> 2 sc’s) –> asymm (1 sc –> 1 sc + 1 differentiated cell)
- con’t for several cycles –> sc’s apoptose
neuroglial migration
- 6 layers. younger cells move past older ones (inside out)
- 1st = preplate
- 2nd = cortical plate (permanent)
neuroglial organization
“gyrification”=cortical folding (probably from speed of cortex expansion relative to WM)
-require right #cells (proliferation) & right order (migration)
problems with brain proliferation, migration or organization
- proliferation-too many or not enough cells
- migration-abN located cells
- organization- too many or few folds
Hemimegalencephaly
- “hamartomatous overgrowth” of part vs total cerebral hemisphere 2/2 differentiation/migration failure.
- big side & Vt
Rasmussen’s encephalitis
- atrophic cerebral hemisphere –> ex vacuo dilation Vt.
- AI, <10 yrs
What to consider in setting of 1) mismatched hemisphere size + 2) dilated Vt.
- Hemimegalencephaly, Rasmussen’s encephalitis & Dyke- Davidoff Masson (cerebral heme-atrophy).
- ass w/ polymicrogyria, pachygyria and heterotopia
Dyke-Davidoff Massons (cerebral hemi-atrophy)
V similar to Rasmussen encephalitis + UL skull thickening & expanded sinuses
- super sag sinus & fissure moved across midline
- 2/2 in utero/childrehood stroke
Lissencephaly spectrum
- abN migration
1) Classic type 1
2) double cortex band heterotopia
3) lissencephaly “cobblestone” type 2
4) periVt nodular heterotypic
Lissencephaly Classic Type 1-findings, ass, genetics/epidemiology
- failure to migrate both in # & order –> 4 layers (reverse order) diffuse depot btw Vt & pial surf –> no folding
- smooth surface, thick cortex, figure 8 brain via shallow vertical Sylvian fissures
- colpocephaly
- Autosomal, M=F, ?ass w/ CMV
Double cortex band heterotopia- Findings, ass, genetics/epidemiology
- mildest form lissencephaly
- disorgz/undermigration –> 2nd layer of cortical neurons deep to more superficial cortex
- “double cortex”
- ass with seizures
- X linked, F>M
Lissencephaly “cobblestone” type 2-findings, MC loc, ass
- overmigration neurons –> additional layer of cortex composed of GM nodules (var size/shape)
- MC loc adj to sylvian fissure
- ass w/ congenital musular dystrophy and retinal detachment
Periventricular nodular heterotopia
- failed neuron migration –> GM nodular depo along Vt
- ass w/ seizure do’s
When can you detect DW and DW variant?
OB US >18 wks gestation
periVt nodular heteroptopia vs subependymal tubers TS
tubers T2 brighter, +/- Ca
Heterotypic grey matter
-Heterotopia (HTP): Abnormally located gray matter (GM) due to foreshortened or prolonged neuronal migration
Anywhere from periventricular germinal zone to pia
-Ectopic nodular or ribbon-like foci following GM signal intensity on every MR sequence
-Locations: Periventricular, subcortical, pial
Periventricular nodular HTP (most common)
Band HTP ~ laminar HTP, double cortex
Subcortical nodular HTP (focal or multinodular)
Pial: “Cobblestone” cortex
polymicrogyria- findings, ass
- abN orgz: insult –> obliteration layer 5 –> superficial layers overfold & fuse –> excessive/disorgz gyral convolutions with shallow sulci –> nodular
- Perisylvian. UL or BL
- Zika = mcc in Brazil, SA
Schizencephaly- what/findings, types, ass
-abN org: cleft of brain lined by GM extending from cortical surface to Vt.
- closed lip (20%, less severe)-cleft wall closely apposed/fused. +/- nipple of GM at LV
- open lip (80%, more severe)- cleft walls separated by CSF
-ass- absent SP (70%), focally thinned cc, optic n hypoplasia (30%), epilepsy
hydrancephaly & porencephalic cyst
- vascular insult –> encephalomalacia (necrosis of GM & WM–> cystic degeneration)
- not lined by GM
- scoop of ice cream (porencephalic cyst) vs whole pint (hydrancephalic)
Hydrancephaly: Causes, what’s preserved, ass
BL ICA occlusion –> massive destruction BL cerebral hemispheres
- cerebellum, mb and falx preserved
- *Herpes (classic), toxo, CMV
classic cephalocele location
occipital
- Cephalocele-what is it?
- What are the contents of “meningocele”, “meningoencephalocele”, “encephalocele”, “cystocele”, “myelocele”
Cephalocele=umbrella term for herniation of cranial contents through a defect in the skull
- meningocele= CSF, meninges
- meningoencephalocele=encephalocele- CSF, meninges, brain
- cystocele-CSF, meninges, Vt
- myelocele- SC
Chiari Malformation types
- I-tonsillar herniation +/- cervical syrinx
- 1.5-1 +2, no nt defects
- II- (less tonsillar herniation.) Vermian displacement.
- III- (Chiari II) + occipital encephalocele
- IV-forget it exists
Classic features chiari II
low lying torcula, tectal beaking, hydrocephalus, clival hypoplasia
Chiari I-MOA, clinical syx, ass
- MOA: underdevelopment pst fossa –> overcrowding, downward displacement. (or less commonly s/p trauma)
- > 5 mm tonsillar herniation below basion/opisthion level
- ass- cervical syrinx, klippel-feil syndrome. NO nt defect.
- syx’s- 1) occ ha (worse w/ sneezing) 2) weakness/spasticity/loss of proprioception via P on cord
Klippel-Feil Syndrome
congenital spinal fusion
Chiari II-classic findings & associations
- cerebellar herniation (more vermian than tonsillar)
- low lying torcula
- tectal beaking
- clival hypoplasia
- banana and lemon signs
- obliteration cisterna magna
- elongated, effaced 4th Vt
- only seen in pst w/ nt defect
- classic associations=lumbar myelomeningocele, cc hypo genesis, spina bifida
- neurumuscular defects, ex: clubfoot
Chiari III
- Chiari II + occipital encephalocele containing cerebellum and/or bs, occipital lobe, +/- 4th Vt
- ass: cervical syrinx, tether cord, hydrocephalus, agenesis of cc
medial temporal sclerosis
hippocampal volume loss (BL 10%) + gliosis/scar (T2 bright)–> loss of normal morphology/interdigitations
- MCC partial complex epilepsy
- add findings (less commonly described)-IL fornix & max body atrophy), CL amygdala enlargement
Craniosynostosis
- Premature fusion of one or several sutures
- people with Premature fusion have trouble getting dates to the Prom
- sporadic (85%), syndromic (15%)
Order of fusion of sutures
metopic (frontal) (front –> back) –> coronal (lat –> med) –> lamboid (lat –> med) –> sagittal (back –> front)
Me Can Love Smelling!
Which craniosynostosis are idiopathic?
sagittal & UL coronal
Names ass w/: sagittal, lamboid (BL), coronal and metopic synostosis
- sagittal= scaphocephaly or dolichocephalic
- lamboid (BL)=turricephaly
- coronal =bradycephaly
- metopic= trigonocephaly
Trigonocephaly
- triangular shape of skull 2/2 metopic (frontal) synostosis preventing transverse growth
- hypotelorism (eyes close together)
- medial orbit slanted up
- single suture ass w/ cognitive disorders (growth restriction of FL)
Brachycephaly
- coronal synostosis (UL > BL)
- UL-IL flattening, superolateral elevation orbit (harlequin eye), CL protrusion (frontal bossing)
- BL ass w/ syndromes
Harlequin eye deformity
orbital superolateral elevation
anterior plagiocephaly
UL coronal synostosis
posterior plagiocephaly
UL lambdoid synostosis
-+/-posterior ear movement
deformational plagiocephaly
benign positional molding