Ch. 11 - Developmental Abnormalities Flashcards
Arachnonid Cyst Definition
benign developmental cysts along craniospinal axis.
most common location of arachnoid cyst.
Sylvian fissure (50%) > cerebellopontine angle = quadrigeminal= supra sellar (10%) > other
location determines sx
sylvian fissure arachnoid cyst presentation
male > female. can be asymptomatic
classic: raised ICP and seizures
rare: rupture = focal neuro deficits
cerebellopontine angle arachnoid cyst presentation
sensorineural hearing loss, impairment of CNV, ataxia
suprasellar arachnoid cyst presentation
hydrocephalus, visual impairment, endocrine dysfxn
cerebral convexity arachnoid cyst presentation
seizures, HA, progressive hemiparesis
kids: asymmetrical enlargement of head
quadreminal arachnoid cyst presentation
mimic pineal masses. obstructive hydrocephalus and increased ICP
dx arachnoid cysts
CT/MRI, usually incidentalomas
tx arachnoid cyst
- nothing if asymptomatic/no obstruction, regular follow up
2. craniotomy and drainage vs shunting
chiari malformation types
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
syringomyelia
cavitation w/i spinal cord but outside central canal
hydromyelia
dilation of central canal 2/2 CSF cannot exit @ foramen of lushka/magendie and are transmitted down central canal
chiari malformation common association
syringomyelia, hydrocephalus
uncommon: CV anomolies, imperforate anus
causes of hydrocephalus in chiari
aqueduct stenosis/atresia/forking, fusion of superior/inferior colliculi, compression in posterior fossa
theories behind chiari malformation
- tethered cord
2. differential pressure in intracranial/intraspinal fluid
Chiari I presentation
adolescent/adult-onset HA cape-like loss of pain/temp, long track signs (LE spasticity, UE paralysis), bulbar features 2/2 syrinx formation
Chiari II presentation
infant-onset. assoc. w/ myelomeningocele, progressive hydrocephalus, brainstem dysfxn (apnea, decreased gag, nystagmus, spastic paresis), adolescent/adult onset similar to chiari 1
How to dx chiari malformation
MRI - displacement of cerebellum into upper cervical canal
cause of hydromyelia
chiari malformations
tx chiari malformation
- posterior fossa and upper cervical decompression
2. shunt syrinx
craniovertebral jxn abnormalities
jxn of foramen magnum, occipital bone and atlas (C1)/axis (C2) resulting in underlying neurologic compression
basilar invagination
upward invagination of base of skull near foramen magnum into posterior fossa, shortening of clivus, odontoid protrusion
causes of basilar invagination
Paget’s disease, osteomalacia, hyperPTH, Osteogenesis imperfecta
presentation basilar invagination
quadriparesis, dysphagia, respiratory difficulty, nystagmus, occipital HA
platybasia
obtuse basal angle joining the plain of the clivus with the plane of the anterior fossa
atlantoaxial dislocation associated with…
fusion of occiput to atlas and fusion of C2-C3 causes adjacent joint dz and instability, rheumatoid arthritis, trauma
Dandy Walker cyst
cystic enlargement of 4th vent, hypoplasia of cerebellum, hydrocephalus of 3rd and lateral ventricles
dandy walker cyst presentation
infantile: hydrocephalus
childhood: ataxia, delayed motor development
dandy walker cyst diagnosed via
CT/MRI
Dandy walker cyst tx
shunting of cyst
spinal dysraphism
incomplete or faulty closure of dorsal midline ambryologic structures ie (myelomeningocele, meningocele, lipomyelomeningocele, occult spinal dysaphism)
spina bifida occulta
bony defect of lamina in lumbosacral spine, asx, 20% of adults
most common spinal dysraphism
myelomeningocele: protrusion of neural elements through vertebral defect into meningeal lined sac
myelomeningocele presentation
irreversible neuro deficit 2/2 spinal cord injury
tx myelomeningocele
untether cord, reduce neural tissue into intervertebral canal
lipomyelomeningocele
lipomatous tissue extends intradurally and interwoven with rootlets of cauda equina
lipomyelomeningocele presentation
progressive neuro deficits (bowel/bladder dysfxn, back pain, progressive paralysis 2/2 tethered cord
lipomyelomeningocele tx
surgical resection of tumor, untether spinal cord
meningocele
cystic lesion lined by meninges and contains CSF, no neural tissue
occult spinal dysraphism
lumbar spinal disorders that produce progressive neurologic dysfunction 2/2 tethered cord (intraspinal lipoma, dermoid tumors, diastematomyelia)
most common cutaneous finding of occult spinal dysraphism
overlying skin lesions: dimple, sinus tract, fatty mass tuft of hair
sx. occult spinal dysraphism
bowel and bladder disturbance, progressive weakness of legs/feet, back pain, sensory disability, progressive scoliosis
diastematomyelia
spinal cord bifid –> progressive neurologic dysfunction
craniosynostosis
premature closure of cranial sutures
normal closure time for antereior and posterior fontanelles
anterior: 3-6 months, posterior 16-18 mo
most common primary craniosynostosis
sagittal synostosis = head growth in occipitofrontal diameter = long narrow head
common in males
cranial synostosis
head expands superiorly and laterally
cranial synostosis SE
increased ICP
cranial synostosis tx
correct cranial deformity, relieve effects of raised ICP
