Neurology I- VI Flashcards
Anencephaly
Encephalocele
myelomeningocele
Arnold-chiari malformation
Myeloschisis
These conditions have problem with what neural developmental process?
Primary neurulation (dorsal induction)
3-4 weeks
FYI: myeloschisis is a flat neural tube defect without a layer of skin covering the opening in the spine. (the spinal cord and the surrounding nerve tissue are also exposed to the amniotic fluid. similar risks and symptoms as myelomeningocele)
what does each of the following Prefix/Suffix mean?
An- or a -
encephalo-
myelo-
meingo -
holo -
- cele -
pros -
An- or a - : “not”, “without”
encephalo- : “brain”
myelo- : “spinal cord”
meningo - : “membrane” , “meinges, coverings of the brain and spinal cord”
holo - : “entire”, “complete” (i.e. no cleavage)
- cele : “hernia”, “swelling”
pros - : “before”, “forward”
tethered cord, lipoma, teratoma spinal cysts, myelocystocele, meningocele-lipomeningocele
These conditions have problem with what neural developmental process?
Secondary neurulation (dorsal induction)
4-7 weeks
These are are spinal cord and lower sacral segment
aprosencephaly
holoprosencepahly
Midline development defect:
agenesis of corpus callosum,
agenesis or absence of septum pellucidum,
septo-optic dysplasia
These conditions have problem with what neural developmental process?
Prosencephalic development (ventral induction)
(ventral induction)
2-3 months
Micrencephaly
Macrencephaly
These conditions have problem with what neural developmental process?
Neural and glial proliferation
3-4 months
Micrencephaly: abnormal smallness and underdevelopment of brain
Macrencephaly: hypertrophy of the brain
Schizencephaly
Lissencephaly
Pachygyria
Polymicrogyria
These conditions have problem with what neural developmental process?
Neuronal migration
3-5 months
Schizencephaly: abnormal clefs of the brain
Lissencephaly: underdevelopment of gyri, smooth brain
Pachygyria: broad, abnormally large gyri, lead to less sulci
Polymicrogyria: numerous small convolutions
Mental deficiency, Trisomy 21, Fragile X, Autism, Angelman, Prematurity
has issue in what neural development process.
Neuronal organization
(axonal outgrowth and proliferation, dendritic and synapse, synaptic rearrangements
what is the last pathway to myelinate
association bundle (prefrontal cortex with temporal and parital lobe): complete at 32 yrs of age.
myelination normally happens birth to years.
Corticospinal tract myelinate 38 wk GA to 2 year.
Anecephaly is due to failure of __ closure. (It happens within __day of gestation)
Encephalocele is due to failure of __ closure.
Myelomeningocele is due to failure of ___ closure
Anecephaly - anterior tube closure (within 26 days)
Encephalocele - rostral neural tube closure
Myelomeningocele - posterior neural tube closure
All are Primary neurulation defect
How are Anecephaly and Aprosencephaly different?
Anecephaly: primary neurulation defect. failure of anterior tube closure. Degeneration of forebrain (no skull, scalp, large amount of brain tissue).
female > male
hispanic women, increase risk with maternal hyperthermia, maternal folate, copper, zinc defieincy.
^ recurrent risk 2-6%.
association with other abnormalities
Aprosencephaly: abnormal development in prosencephalic stage in formation. There is abscence of telencephalon and diencephalon with porencephalic remnant. minimal brain volume. Has intact skull, hair, and dermal coverings.
cyclopia or no eye. associated external genitalia and limb abnormalities.
autosomal recessive
For anecephaly, during prenatal testing, what level is elevated in maternal serum
maternal alpha-fetoprotein.
Encephalocele is associated with what syndrome?
Does encephalocele has a genetic cause?
Meckel-Gruber syndrome.
Genetic cause of encephalocele is suggested. risk higher in families with history of NTD.
Maternal alpha-fetoprotein level in encephalocele is __ ? (higher, lower, norrmal)
normal
where is the most common location of defect in encaphlocele? which locations has better prognosis.
Occipital more common
Frontal has better prognosis
what is cranial meningocele?
a type of encephalocele but does not have CNS tissue protruding through the lesion.
Difference between Meningocele and Myelomeningocele?
Meningocele: defect in spinal canal, meninges herniate through the defect.
Myelomeningocele: spinal cord, meninges herniat through the defect.
What maternal medications and what maternal medical conditions increase risk of NTD?
valprroate
carbamazepine
maternal diabetes
NTD might need VP shunt due to risk of hydrocephalus
level of lesions, segmental innervation, reflex present and ambulation potential
Do we need to know? (page 6)
What are the difference and similarities between Arnold-Chiari malformation and Dandy-Walker Malformation?
Name/describe two types of Arnold-chiari malformation.
What other CNS conditions are Dandy-Walker highly associated with?
Arnold-Chiari Malformation:
- primary neurulation defect.
- caudal displacement of cerebellar tonsils below foramen magnum.
*Type I: most common. caudal displacement of cerebellar tonsils below foramen magnum. 4th ventricle and brainstem in normal position.
associate with syringomyelai, hydromelia, skeletal anoamlies.
*Type II: in infants. more extensive elongation and caudal displacement of cerebrella tonsils, 4th ventricles, choroid plexus and brainstem, into the cervical spinal canal.
associated with hydrocephalus, myelomeingocele.
Dandy-Walker Malformation:
- occurring very early in neurological developmental phase.
- AGNESIS / Hypoplasia of the cerebellar vermis, cystic dilation of the 4th ventricle, enlargement of the posterior fossa.
- associated with hydrocephalus, risk of motor and cognitive delays.
holoprosencephaly’s epidemiology and association
increase risk in IDM. familiar reoccurences described.
30-50% w/ chromosomal anomalies (T13)
50% w/ extracranial abnormalities.
Holoprosencephaly happens in __ stage of neurodevelopment? It’s the primary defect in __?
prosencephalic stage
defect in cleavage.
4 types of holoprosencephaly
middle interhemispherice varient (MIHV)
Lobar
Semilobar
Alobar
Agenesis of Corpus Calllsum happens in __ stage of neurodevelopment? It’s the primary defect in __?
cause/inference
prosencephalic stage
defect in mideline development
some x-linked dominant and some autosomal recessive.
Fetal infection earlier in pregnancy or intrauterine alcohol exposure.
What is septum pellucidum?
Abesecence of septum pellucidum is associated with what?
double thin vertical membrane separating the anterior horns of the left and right lateral ventricles
(cavum septum pellucidum is the potential space in between the two double membranes)
learning disabilities, vision problems, seizures, behavioral issues, septo-optic dysplasia
Diagnosis of septo-optic dysplasia criteria
2 out of 3 features:
optic nerve hypoplasia
pituitary gland dysfunction
absence of septum pellucidum
Name the three main cerebral arteries and the area of they supply
Anterior Cerebral Artery:
from internal carotid
supply medial, frontal, parietal lobes, AND caudate
Middle:
from internal carotid
supply lateral hemispheres
Posterior:
from basilar artery, which from vertebral artery
supply midbrain, occipital lobes and inferior temporal lobes
cerebral perfusion pressure (CPP) equation
CPP = ?
CPP = MAP - ICP
ICP: intracranial cerebral pressure
MAP: mean arterial pressure
If given BP and not MAP, remember:
MAP = 2/3 DBP + 1/3 SBP
autoregulation with blood pressure change:
describe the curve in premature infant and curve in normal state
what’s x-axis and what’s y-axis
x-axis: BP
y-axis: cerebral blood
autoregulation: with increase BP, cerebral blood flow can remain stable for a period of time.
no regulation: BP and cerebral flow are directly correlated.
PaO2 and PaCO2 impact on CBF (cerebral blood flow)
Increased PaCO2 increases CBF (cerebral blood flow)
Decrease PO2 increases CBF.
name factors that increase CBF
^ PaCO2, decrease PaO2
^ BP in asphyxiated infant/ premature infant
dopamine
decrease hemoglobin (Hgb) concentration
increase proportion of fetal hemoglobin
hypoglycemia
seizures.
name all cranial sutures (4 total)
metopic,
coronal
sagittal
lambdoidal
Types of Craniosynostosis (and what suture was closed)
Scaphocephaly or Dolichocephaly (sagittal suture closure)
most common
male > female
small or absent anterior fontanel
more benign, less likely to associate with other lesions, brain growth normal.
surgery for cosmetic
Frontal plagiocephaly (unilateral coronal suture)
female > male
^ developmental delay
associated w/ Crouzon and Apert syndrome
surgery to improve neurological sequelae
Brachycephaly (b/l coronal suture)
Carpenter syndrome
Trigonocephaly (metopic suture)
male > female
associated for hypotelorism
surgery for cosmetic
Occipital plagiocephaly (unilateral lamboid suture)
not common
Multiple suture involvement
combine above skull shapes.
increased risk of ^ ICP, ^ mental deficiency. surgery soon.
common syndromes and causes of cranyosynostosis
crouzon, apert, carpenter,
idiopahtic hypercalcemia, rickets, hypophosphatemia
syndromes associated with Microcephaly
(decrease HC > 2-3 standard deviation below mean)
chromosomal: T 12, 18, 21
deleition 13q
CHARGE
Meckel-Gruber syndrome
Smith-Lemli-Opitz syndrome
Intrauterine or postnatal infection (CMV, Zika)
IUDE (alcohol. isotretinoin)
prenatal radiation exposure
maternal phenylketonuria and phenylketonuria
(Meckel-Gruber syndrome: autosomal recessive, lethal malformation
Triad of occipital encephalocele, bilateral polycystic kidneys and post axial polydactyly.)
syndromes associated with Macrocephaly
(^ HC > 3 SD above mean, without hydrocephalus or cranial mass)
Benign family macrocephaly ( 50%, AD, m > f, normal developmental outcome)
Beckwith-Wiedemann syndrome
Neurofibromatosis
Soto syndrome
Fragile X syndrome
Achondroplasia
Aqueductal stenosis
what is Mobius syndrome
b/l facial paresis
due to hypoplasia of cranial nerve nuclei
expressionless face
no treatment.
when is clonus normal and when is it not normal
5-10 beats normal in newborn
abnormal if present > 3 months of age.
When does Palmer reflex appear and when does it disappear?
Persistent palmer reflex means what?
appear by 26 weeks (one of the earliest), establish by 32 weeks.
disappear in 2-4 month
asymmetric = peripheral injury (root, plexus, or nerve)
persistance = athetoid cerebral palsy
non-habituating = cerebral injury
sucking relex appears by what age ? and establish by what age?
28 weeks
32-34 weeks (when start to learn to feed)
Moro reflex appear at what age and disappear at what age
if not symmetric, what does it indicate ?
if non-habituating, what does it indicate?
appear at 30-34 week. disappear by 2-4 month.
if asymmetric, peripheral injury.
if non-habituating, + cerebral injury
name three reflexes that appeared earliest (26 - 28 weeks)
Palmer (26 wk)
Plantar (26 wk)
Sucking (28 wk)
name three reflexes disappearing around 2 - 4 m.
Palmer (2-4 m)
Crossed extensor (2 m)
Moro (2-4 m)
Placing and Stepping (2-3 m)
describe CSF fluid path:
CSF made in lateral ventricles by choroid plexus (0.37 ml/min) > intraventricular foramen of Munro > 3rd ventricle > cerebral aqueduct of Sylvius > 4th ventricle > lateral foramens of Kuschka and Magendie > subarachonoid space > brainstem, cerebellum, spinal cord.
what does choroid plexus do
secreting or absorbing CSF
choroid plexus cysts: what are they and what is their clinical significance
neuroepithelial folds filled with CSF and debris
detect at 11 wk and disappear by 26 week.
normalin 0.5%
small percentage infant has T18
What at CSF fluid made off
99% water, Na major cation
remade very 5-7 days.
10-30ml in preterm infant
40 ml in term infant
in EEG, when does “delta brushes” in central region appear and when does it disappear?
Delta brushes
Appear: 29-30wk
Disappear: 36-37 wk from central region, 38-40 wk from occipital region.
in EEG, when does activity become continous?
31-33 weeks
(also first synchrony during active sleep around 31-33 weeks)
in EEG, when does EEG changes with external stimuli?
34-35 weeks
EEG Pattern:
Central positive sharp waves
characteristic pattern in preterm infants with PVL
EEG Pattern:
Hypsarrhythmia
infantile myoclonic spasms (after 2 months age)
EEG Pattern:
Background depression
occurs after generalize insults (i.e. HIE, meningitis, encephalitis, metabolic disorder)
- if unilateral: one-sided cerebral lesion caused by ischemia, hemorrhage, or abnormal development
- persistence of background dpression > poor prognostic sign
EEG Pattern:
Burst Suppression
intermediate stage between depression and electrocerebral silence
no EEG response to external stimuli
poor prognosis
Electrocerebral silence
persistence > 72 hr indicates cerebral cortical death
not always have brainstem death
if brainstem activity, survived pt in persistent vegetative state.
Periodic discharges on EEG
Preterm infants: associated with various insults in prematurity
Term infants: associated with infarction in the MCA area
Multifocal sharp waves
high voltage for long periods
what is aEEG?
filtered or compressed EEG using 1-2 channels
Used in NICU to evaluate infants with suspected HIE.
Describe continuous aEEG patten vs. discontinuous aEEG pattern (preterm infant)
Continuous: normal, term infant. smooth, cyclic “fuzzy caterpillar”. Amplitudes: 10-25 mcV
Discontinuous: preterm. Amp ~ 5-10 mCV. no cyclic.
Seizures: aEEG pattern
“arches”, “saw tooth”
increases in min and max amplitude, periods of decreases amplitutde.
what is MRI/DWI and what can it detect?
MRI w/ diffusion weighted images. Measures random Brrownian motion of water molecules
earlier identification of ischemic stroke.
what is CT scan superior to MRI for?
detecting intracranial calcifcation
CT can detect bleeding/fluid in subdurral, subarachnoid space and in the posterior fossa.
what are causes of Obstructive hydrocephalous (name 6)
- PHH (most common)
- Aqueductal stenosis
- Agenesis of corpus callosum
- Dandy-Walker malformation
- Congenital hydrocephalus
- Mass
Aqueductal stenosis:
pathogenesis
etiologies
congenital obstruction of the aqueduct (duct connecting 3rd and 4th ventricles) -> 3rd land lateral ventricular dilation
Etiologies:
1. possible unrecognized viral illness (mumps, rubella, parainfluenza)
2. associated with Arnold-Chiari malformation
3. x-linked recessive: adducted thumbs, agenesis of corpus callosum, mental deficiency
4. autosomal recessive (nonfamilial) w/ associated VACTERL.
Congenital hydrocephalus
Timing of disease:
Etiology:
management:
onset in utero, presentation in the first days after birth.
Etiology:
Dandy-walker (5-10%), teratogenesis (radiation exposure), intrauterine infection (toxo, CMV), maternal malnutrition, genetic factors, tumor, IVH, vein of Galen)
VP shunt.
in HIE, when does seizure occur?
how do they respond to anti-convulsant treatment
12-24 hours.
resolved by 5-7 days
does not respond well to anti-convulsant treatment
what are three phases in HIE
latent (1-6 hr) -> hypoperrfusion
secondary (6-24hr to days) -> hyperperfusion
Tertiary (weeks to years) -> normalisation
Meckel Syndrome - defect and triad?
Defect with cilia
Triad:
Encephaloceles
Multicystic kidneys
Polydactyly (fingers or toes)
Chemical conjunctivitis - onset and characteristics?
Onset: within 24 hours after exposure
Characteristics:
Following prophylaxis
Decreased incidence because less usage of 1% silver nitrate for
prophylaxis
Negative culture
Spontaneously resolves within 48 hours
Bacterial conjunctivitis - onset and characteristics?
Onset: 24-48 hours of age (can be later in life)
Characteristics:
Staph aureus (most frequent organism, golden crust around eyelids), also secondary to Group B Streptococcus, Haemophilis influenzae (dacrocystitis), Strep pneumonia (dacrocystitis), Pseudomonas aeruginosa
Gonoccal conjunctivitis - onset and characteristics?
Onset: 2 to 5 days of life
aka gonococcal ophthalmia neonatorum
Characteristics:
Abrupt onset of extremely copious, purulent bilateral discharge
Medical emergency because can progress to involve cornea and ulceration/perforation if untreated
Treat with 3rd generation cephalosporin
Can prevent with prophylaxis (0.5% erythromycin most common, ideal if applied < 1 hour of age, decreases incidence of gonorrheal conjunctivitis from 10 to 0.5%)
Chlamydial conjunctivitis - onset and characteristics?
Onset: 5-14 days of life (can be earlier if premature rupture of membranes)
Characteristics:
~ 8/1,000 births
Most common cause of coniunctivitis in 1st month of life
In ~1/2 of infants with colonized mothers
Typically bilateral
Initially watery discharge that becomes purulent
Often associated with chlamydia pneumonia
Diagnose by Giemsa-stain of conjunctival scrapings
Treat with oral erythromycin x 14 days (20% require second course)
Herpes simplex conjunctivitis - onset and characteristics?
Onset: Broad range (4 days to 3 weeks of age)
Characteristics:
Most frequent viral etiology
May also have keratitis, chorioretinitis, retinal dysplasia
Assess for systemic herpes and herpes encephalitis
T12-L 2,
thoracolumbar,
Reflex. Ambulation potential?
None
Full braces, long term ambulation unlikely
L3-L4
Reflex present. Ambulation potential
Knee jerk
May ambulate with braces and crutches
L5 - S1
Reflex. Ambulation potential?
Ankle jerk present
Ambulate with or without short braces
S2-S4,
Reflex. Ambulation potential?
Anal wink present
Ambulation without braces
