Ch. 11 - Developmental Abnormalities

Question 1

Arachnonid Cyst Definition

Answer 1

benign developmental cysts along craniospinal axis.

Question 2

most common location of arachnoid cyst.

Answer 2

Sylvian fissure (50%) > cerebellopontine angle = quadrigeminal= supra sellar (10%) > other

location determines sx

Question 3

sylvian fissure arachnoid cyst presentation

Answer 3

male > female. can be asymptomatic

classic: raised ICP and seizures
rare: rupture = focal neuro deficits

Question 4

cerebellopontine angle arachnoid cyst presentation

Answer 4

sensorineural hearing loss, impairment of CNV, ataxia

Question 5

suprasellar arachnoid cyst presentation

Answer 5

hydrocephalus, visual impairment, endocrine dysfxn

Question 6

cerebral convexity arachnoid cyst presentation

Answer 6

seizures, HA, progressive hemiparesis

kids: asymmetrical enlargement of head

Question 7

quadreminal arachnoid cyst presentation

Answer 7

mimic pineal masses. obstructive hydrocephalus and increased ICP

Question 8

dx arachnoid cysts

Answer 8

CT/MRI, usually incidentalomas

Question 9

tx arachnoid cyst

Answer 9

1. nothing if asymptomatic/no obstruction, regular follow up

2. craniotomy and drainage vs shunting

Question 10

chiari malformation types

Answer 10

type 1: caudal displacement of cerebellar tonsils below foramen magnum
type 2: caudal displacement of cerebellar vermis, 4th vent, and medulla
type 3: caudal displacement of cerebellum and brainstem

Question 11

syringomyelia

Answer 11

cavitation w/i spinal cord but outside central canal

Question 12

hydromyelia

Answer 12

dilation of central canal 2/2 CSF cannot exit @ foramen of lushka/magendie and are transmitted down central canal

Question 13

chiari malformation common association

Answer 13

syringomyelia, hydrocephalus

uncommon: CV anomolies, imperforate anus

Question 14

causes of hydrocephalus in chiari

Answer 14

aqueduct stenosis/atresia/forking, fusion of superior/inferior colliculi, compression in posterior fossa

Question 15

theories behind chiari malformation

Answer 15

1. tethered cord

2. differential pressure in intracranial/intraspinal fluid

Question 16

Chiari I presentation

Answer 16

adolescent/adult-onset HA cape-like loss of pain/temp, long track signs (LE spasticity, UE paralysis), bulbar features 2/2 syrinx formation

Question 17

Chiari II presentation

Answer 17

infant-onset. assoc. w/ myelomeningocele, progressive hydrocephalus, brainstem dysfxn (apnea, decreased gag, nystagmus, spastic paresis), adolescent/adult onset similar to chiari 1

Question 18

How to dx chiari malformation

Answer 18

MRI - displacement of cerebellum into upper cervical canal

Question 19

cause of hydromyelia

Answer 19

chiari malformations

Question 20

tx chiari malformation

Answer 20

1. posterior fossa and upper cervical decompression

2. shunt syrinx

Question 21

craniovertebral jxn abnormalities

Answer 21

jxn of foramen magnum, occipital bone and atlas (C1)/axis (C2) resulting in underlying neurologic compression

Question 22

basilar invagination

Answer 22

upward invagination of base of skull near foramen magnum into posterior fossa, shortening of clivus, odontoid protrusion

Question 23

causes of basilar invagination

Answer 23

Paget’s disease, osteomalacia, hyperPTH, Osteogenesis imperfecta

Question 24

presentation basilar invagination

Answer 24

quadriparesis, dysphagia, respiratory difficulty, nystagmus, occipital HA

Question 25

platybasia

Answer 25

obtuse basal angle joining the plain of the clivus with the plane of the anterior fossa

Question 26

atlantoaxial dislocation associated with...

Answer 26

fusion of occiput to atlas and fusion of C2-C3 causes adjacent joint dz and instability, rheumatoid arthritis, trauma

Question 27

Dandy Walker cyst

Answer 27

cystic enlargement of 4th vent, hypoplasia of cerebellum, hydrocephalus of 3rd and lateral ventricles

Question 28

dandy walker cyst presentation

Answer 28

infantile: hydrocephalus childhood: ataxia, delayed motor development

Question 29

dandy walker cyst diagnosed via

Answer 29

CT/MRI

Question 30

Dandy walker cyst tx

Answer 30

shunting of cyst

Question 31

spinal dysraphism

Answer 31

incomplete or faulty closure of dorsal midline ambryologic structures ie (myelomeningocele, meningocele, lipomyelomeningocele, occult spinal dysaphism)

Question 32

spina bifida occulta

Answer 32

bony defect of lamina in lumbosacral spine, asx, 20% of adults

Question 33

most common spinal dysraphism

Answer 33

myelomeningocele: protrusion of neural elements through vertebral defect into meningeal lined sac

Question 34

myelomeningocele presentation

Answer 34

irreversible neuro deficit 2/2 spinal cord injury

Question 35

tx myelomeningocele

Answer 35

untether cord, reduce neural tissue into intervertebral canal

Question 36

lipomyelomeningocele

Answer 36

lipomatous tissue extends intradurally and interwoven with rootlets of cauda equina

Question 37

lipomyelomeningocele presentation

Answer 37

progressive neuro deficits (bowel/bladder dysfxn, back pain, progressive paralysis 2/2 tethered cord

Question 38

lipomyelomeningocele tx

Answer 38

surgical resection of tumor, untether spinal cord

Question 39

meningocele

Answer 39

cystic lesion lined by meninges and contains CSF, no neural tissue

Question 40

occult spinal dysraphism

Answer 40

lumbar spinal disorders that produce progressive neurologic dysfunction 2/2 tethered cord (intraspinal lipoma, dermoid tumors, diastematomyelia)

Question 41

most common cutaneous finding of occult spinal dysraphism

Answer 41

overlying skin lesions: dimple, sinus tract, fatty mass tuft of hair

Question 42

sx. occult spinal dysraphism

Answer 42

bowel and bladder disturbance, progressive weakness of legs/feet, back pain, sensory disability, progressive scoliosis

Question 43

diastematomyelia

Answer 43

spinal cord bifid --> progressive neurologic dysfunction

Question 44

craniosynostosis

Answer 44

premature closure of cranial sutures

Question 45

normal closure time for antereior and posterior fontanelles

Answer 45

anterior: 3-6 months, posterior 16-18 mo

Question 46

most common primary craniosynostosis

Answer 46

sagittal synostosis = head growth in occipitofrontal diameter = long narrow head common in males

Question 47

cranial synostosis

Answer 47

head expands superiorly and laterally

Question 48

cranial synostosis SE

Answer 48

increased ICP

Question 49

cranial synostosis tx

Answer 49

correct cranial deformity, relieve effects of raised ICP