Malformations and Developmental Diseases

Question 1

How is a malformation caused?

Answer 1

intrinsic malformation

Question 2

How is a deformation caused?

Answer 2

external force acts upon

Question 3

How is a disruption caused?

Answer 3

a destructive force acts upon

Question 4

When is the neurulation phase?

Answer 4

3-4wks

Question 5

When is the prosencephalic phase?

Answer 5

2-3 mos

Question 6

When is the neuronal proliferation phase?

Answer 6

3-4 mo

Question 7

When is the neural migration phase?

Answer 7

3-5 mo

Question 8

When is the organization phase?

Answer 8

5-postnatal years

Question 9

When does myelination occur?

Answer 9

birth-postnatal years

Question 10

When does neural tube closure occur?

Answer 10

28 days

Question 11

What is the definition of a neural tube defect?

Answer 11

disurbance of formation of neuroectodermal and/or overlynig mesodermal structures or reopening or secondary rupture of closed tube

Question 12

How can neural tube defects be detected?

Answer 12

prenatal folate supplement

Question 13

What are the 3 main types of neural tube defects?

Answer 13

spina bifida
anencephaly
encephalocele

Question 14

Which type of spina bifida causes neural defects?

Answer 14

myelomeningocoele

Question 15

What drug can cause neural tube defects in 1-2% of pregnancies?

Answer 15

valproic acid

Question 16

What are potential complications of myelomeningocoele?

Answer 16

hydrocephalus (type II chiari defect 80%)
meningitis
pneumonia

Question 17

What is a chiari crisis?

Answer 17

downward herniation of the medulla and cerebellar tonsils

Question 18

What is typically missing in anencephaly?

Answer 18

cerebral and cerebellar hemispheres

calvarium, meninges and scalp

Question 19

What is an encephalocele?

Answer 19

broad-based pedunculated masses of cerebral tissue & dura protruding through cranial defect, covered by skin

Question 20

Where is the most common site for an encephalocele?

Answer 20

occupital region, frontal/nasal location also common

Question 21

What is meckel-gruber syndrome?

Answer 21

AR condition
occipital encephalocoele, cleft lip or palate, microcencephaly, micropthalmia, abnormal genitalia, polycystic kidneys and polydactyly

Question 22

What is polymicrogyria?

Answer 22

too many irregular small fused gyri

Question 23

What casues polymicrogyria?

Answer 23

results from the disordered organization of the neurons in the cortex at the time of migration

Question 24

What is agyria?

Answer 24

absence of gyri

Question 25

What are pachygyria?

Answer 25

decreased numbers of broad coarse gyri, brain is small

Question 26

When does agyria or pachygyria occur?

Answer 26

4th month gestation

Question 27

What chromosomes are associated with agyria or pachygyria?

Answer 27

17 & X

Question 28

What are sx of a/pachy-gyria?

Answer 28

``` failure to thrive microcephaly marked developmental delay severe seizure disorder hypoplasia of the optic nerve microphthalmia ```

Question 29

What is miller dieker syndrome?

Answer 29

prominent forehead, bitemporal hollowing, nteverted nostrils, prominent upper lip, micrognathia

Question 30

What is schizencephaly?

Answer 30

unilateral or bilateral clefts within the cerebral hemispheres due to an abnormality of morphogenesis cleft may be fused or unfused, and is usually surrounded by abnormal brain, microgyria

Question 31

What are sx of schizencephaly?

Answer 31

severe MR intractable seizures microcephaly spastic quadriplegia when clefts are bilateral

Question 32

What is arrhinencephaly?

Answer 32

disorders of cleavage of forebrain | ie/holoprosencephaly & olfactory aplasia

Question 33

What are signs/sx of holoprosencephaly?

Answer 33

profound MR, seizures, rigidity, apnea, temperature imbalance, hydrocephalus, facial abnormalities

Question 34

What causes agenesis of the corpus callosum?

Answer 34

an insult to the commissural plate during embryogenesis

Question 35

What are signs/sx of agenesis of the corpus callosum?

Answer 35

usually asymptomatic , margination defects (heterotopia, microgyria, pachygyria) may present with MR, microcephaly, hemiparesis, diplegia and seizures

Question 36

What do you see on CT/MRI for agenesis of the corpus callosum?

Answer 36

widely separated frontal horns with an abnormally high position of the 3rd ventricle

Question 37

What is aicardi syndrome?

Answer 37

severe MR, intractable seizures w/onset between birth and 4 mo age, chorioretinal lacunae hemivertebrae and costovertebral anomalies are common independent activity from both hemispheres as a result of the absence of the corpus callosum

Question 38

What is a type 1 chiari malformation?

Answer 38

chronic tonsillar herniation | assoc w/hydrocephalus, sudden death, cranial nerve palsies, ataxia, long tract signs, syringomyelia

Question 39

What is another name for a type 2 chiari malformation?

Answer 39

arnold chiari malformation

Question 40

What is a type 2 chiari malformation?

Answer 40

herniated cerebellar tissue through foramen magnum with displacement of dorsal medulla causing a hump or Z-shape in brainstem/spinal cord

Question 41

What are signs/sx of a type 2 chiari malformation?

Answer 41

lower cranial nerve defects | arm weakness, spasticity, hydrocephalus sx

Question 42

What is a dandy walker malformation?

Answer 42

agenesis of vermis cystic dilatation of the 4th ventricle enlargement of posterior fossa hydrocephalus is frequently present

Question 43

What are signs/sx of dandy walker malformation?

Answer 43

motor retardation, spasticity and resp failure

Question 44

What is a risk factor for dandy walker malformation?

Answer 44

isotretinoin use during pregnancy

Question 45

What is a syringomyelia?

Answer 45

fluid filled cleft like cavity in spinal cord | assoc w/chiari type 1 malformation and post traumatic

Question 46

What are signs/sx of syringomyelia?

Answer 46

loss of pain/temp, retention of position and vibration senses & motor function onset of symptoms in 2nd and 3rd decades, progressive

Question 47

What happens with perinatal hypoxia/ischemia of white matter? White and gray matter?

Answer 47

white matter necrosis (periventricular leukomalacia) | multicystic encephalopathy

Question 48

What happens with perinatal hemorrhagic lesions?

Answer 48

subependymal germinal plate/matrix hemorrhage

Question 49

What causes cerebral palsy?

Answer 49

perinatal insults

Question 50

What is cerebral palsy?

Answer 50

non-progressive neurologic motor deficit | -spasticity, dystonia, ataxia/athetosis, paresis

Question 51

What does periventricular leukomalacia look like?

Answer 51

sharply defined foci of necrosis in white matter selectively vulnerable oligodendrocytes lost histology: central zone of necrosis, surrounding mineralization of axons

Question 52

What does multicystic encephalopathy look like?

Answer 52

sponge-like glial lined cysts post destruction of both gray and white matter in 3rd trimester

Question 53

Where do most subependymal germinal matrix hemorrhages originate/

Answer 53

germinal zone overlying head of caudate and thalamus | frequently break through into ventricular system or underlying parenchyma

Question 54

What usually precipitates subependymal germinal matrix hemorrhage?

Answer 54

extreme physical distress/prematurity | perinatal occurrence, hemodrynamic instability, mechanical ventilation, hyaline membrane disease

Question 55

Where do grades 1-4 of subependymal hemorrhages invade?

Answer 55

1-confined to germinal matrix 2-germinal matrix & lateral ventricle, no ventricular dilation 3-germina matrix & lateral ventricle, with acute ventricular distention 4- grade 3 plus extension into adjacent brain parenchyma