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