Ch 20 congenital and acquired hydrocephalus Flashcards
Definition of hydrocephalus
accumulation of cerebral spinal fluid in or around the ventricles
Result of hydrocephalus?
ventricular expansion pressure on other parts of the brain impairment of gait atypical eye movements headache vomiting cognitive difficulty
Is hydrocephalus usually a primary or secondary condition
secondary
Can hydrocephalus be acquired or congenital?
either congenital or acquired
Cause of hydrocephalus
obstruction that blocks the normal flow of CSF in the brain
What can cause ventricular dilation
inadequate absorption or overproduction of CSF
loss of brain tissue because of atrophy
When ventricular dilation occurs, what happens?
stretching and enlargement of periventricular white matter fibers –>
demyelination and disruption of development of cerebral white matter
What is the function of CSF flow?
flows in and around the brain and spinal cord
cushion from injury
provide nutrients.
remove potentially toxic metabolic byproducts
hydrocephalus can be understood as a subcortical disconnection syndrome because
because of the injury to the long periventricular pathways that support communication
Is hydrocephalus an isolated condition?
No. It’s usually secondary to other disease process
classification of hydrocephalus is based on
age of origin
site of disruption
whether there is increased and sustained ICP
Types of congenital hydrocephalus?
4 types of congenital hydrocephalus
Which 4 types of congenital hydrocephalus
Spina bifida myelomenigocele
aqueductal stenosis
dandy-walker syndrome
prematurity intravanetricular hemorrhage
Congenital hydrocephalus are (name 3 characteristics)
obstructive
non communicating
internal
Spina bifida myelomeningocele
nonlethal neural type defect that occurs in first 30 days of gestation
most common form of spina bifida
most common cause of congenital hydrocephalus
Spina bifida myelomeningocele accounts for how many % of childhood cases?
70%
What happens in spina bifida? describe
in spina bifida, the portion of the neural tube that eventually forms the vertebrae column does not fuse during embryogenesis
the degree of closure of the neural tube can lead to…
different kinds of spinal lesions apparent at birth
myelomeningocele
open neural tube defect
open spinal cord
CNS is exposed
with meningeal cyst
examples of closed spinal defects
meningocele
spina bifida occulta (closed asymptomatic)
closed spinal dysraphism covered with lipoma (fatty tumor)
diastomyelia (defects of the vertebrae)
spina bifida occulta
common form of spinal abnormality with no protruding spinal sac that us usually not overtly apparent at birth
usually found out with back pain, identified on radiology
rarely associated with hydrocephalus or other brain abnormalities
what happens during spina bifida myelomeningocele
spinal cord protrudes through the meninges
hydrocephalus develops in 90% of infants
- Chiari II malformation of hindbrain
- obstruction of 4th ventricle
abnormal corpus callosum
abnormal cerebellum
C4CC Chiari 4th ventricle Corpus callosum Cerebellum
Chiari II malformation is ubiquitous in association with
myelomeningocele
What is Chiari II malformation?
cerebellar and brainstem extends into skull and bulges through foramen magnum (hole at base of skull where spinal cord passes)
puts pressure on parts of the brain and spinal cord
aqueductal stenosis
narrowing of the aqueduct of Sylvius/cerebral aqueduct which blocks the flow of CSF in the ventricular system.
causes hydrocephalus by congenital narrowing of the adqueduct of Sylvius / cerebral aqueduct
cerebellum usually normal
consequence - more likely to have difficulty looking up (“upward gaze palsy”)
Dandy Walker syndrome
70-80% of children with DWS develop hydrocephalus
Cause of hydrocephalus in people with DWS?
partial or complete absence of the cerebellar vermis (medial part of the cerebellum)
cystic enlargement of the 4th ventricle
cyst formation of the base of the skull (posterior fossa).
C4P
Cerebellar vermis MISSING!
4th ventricle
Posterior fossa cyst
Prematurity Intraventricular Hemorrhage (IVH)
children with prematurity IVH develop hydrocephalus because of hemorrhage involving geminal matrix shortly after birth
happens in very low birth weight infants
hydrocephalus usually non progressive in these case
Which IVH grades are associated with hydrocephalus?
Grades III and IV
Internal hydrocephalus
obstructive hydrocephalus
involves formamen of monro
narrowing of aqueduct of sylvius
results in: accumulation of CSF WITHIN the ventricles increase in ICF ventricular expansion compression of brain
external hydrocephalus
accumulation of CSF and other forms of hydrocephalus OUTSIDE of ventricles
do not necessarily involve increased ICP
involves subarachnoid spaces
communicating hydrocephalus
non obstructive
abnormality in CSF absorption
occurs when the flow of cerebrospinal fluid (CSF) is blocked after it exits the ventricles.
result from a thickening of the arachnoid around the base of the brain, which blocks the flow of CSF from the spinal to the cortical subarachnoid spaces.
ventricular enlargement with accumulated CSF (e.g. dementia)
ICP not always increased
non communicating hydrocephalus
obstructive form of hydrocephalus associated with congenital disorders
can be associated with disorders (e.g. cysts) that obstruct the outflow of CSF into subarachnoid space
normal pressure hydrocephalus
adult onset
accumulation of CSF in the ventricles
increase ICP
may have no obvious cause, but can be due to insult (e.g. tumor, hemorrhage, TBI)
hydrocephalus is usually a secondary condition
risk factors of idiopathic NPH
HTN, vascular disease, diabetes
mortality rates of congenital hydrocephalus
0.7/ 100,000
death rate highest in what group in congenital hydrocephalus
infants
Neural tube defects prevalence
1-10/1000 births
why have rates of neural tube defects decreased?
increased emphasis on folate acid
shunting
Myelomeningocele accounts for ?% of all forms of congenital hydrocephalus
70%
Myelomeningocele ratio of Male : Female
Females more frequently slightly
Aqueductal stenosis incidence rate
5-10/100,000
Aqueductal stenosis accounts for ?% of all forms of congenital hydrocephalus
5-15% of congenital hydrocephalus
aqueductal stenosis is usually detected during infancy because of
head size
control
gaze
Dandy walker syndrome rate
3-5/100,000
Dandy walker syndrome accounts for ?% of all forms of congenital hydrocephalus
5-10%
when is Dandy walker detected?
prenatal diagnosis
1st year of life
why is dandy walker detected during 1st year of life
head size
poor control
gaze problems
Dandy walker is often fatal or non fatal
fatal (50%)
prematurity IVH
determined by grade and not incidence
lowest birth weight and gestational age usually have highest incidence and severity
normal pressure hydrocephalus incidence rate
5-6/100,000
normal pressure hydrocephalus overall prevalence rate
0.5% (usually underestimated)
incidence of NPH increases with?
age
idiopathic NPH prevalence rate?
2-6%
How is NPH diagnosed?
headaches
urinary incontinence
gait abnormality
mental decline
HUGMe
How is NPH treated
reversible with shunting
what determines outcome in spina bifida myelomeningocele?
severity of chiari II malformation direct effects on cerebellar functions tectal beaking hypogenesis of corpus callosum level of spinal lesion
higher level spinal defects are associated with
paraplegia of lower limbs
inability to ambulate
more severe brain malformation
in other congenital hydrocephalus, severity is related to
hydrocephalus
underlying disorder
severity of aqueductal stenosis depends on?
usually pure form of early hydrocephalus
may present with no other brain malformation
abnormality in cerebellum and corpus callosum will have more severe outcomes
severity of Dandy walker depends on?
cystic malformation
degree of underdevelopment of cerebellar vermis
manifestation of DWS?
gait
upper extremity control
prematurity IVH severity outcomes depend on?
prematurity complications
in idiopathic NPH, severity is dependent on?
increase in ICP
compression of ventricles on other parts of the brain
When is spina bifida myeloningocele identified usually?
at birth because of the spinal lesion
if lesion is myeloningocele, then concerns for chiari II malformation and hydrocephalus
When is aqueductal stenosis and DWS identified usually?
infancy because of head circumference
head control
gaze abnormality
IVH is identified on
routine ultrasound
hydrocephalus is a chronic or acute problem?
chronic problem after treatment
treatment of hydrocephalus
shunt implantation that diverts the flow of CSF around the site of blockage
endoscopic third ventriculostomy (ETV)
medication to absorb excessive fluid
surgery to replace spinal defect
where is the shunt usually placed?
right posterior ventricle with valve that drains fluid into the peritoneal cavity
what is endoscopic third ventriculostomy (ETV)
the floor of 3rd ventricle is perforated to drain CSF into an open CSF space, usually the subcistern
NP results for spina bifida
impairment in fine motor skills (2/2 chiari II malformation) ID attention ADHD I
congenital hydrocephalus attention skills
difficulties with orienting and disengaging
stronger regulation when oriented and engaged
(disorder of posterior attention systems)
congenital hydrocephalus NP profile
NVLD
verbal IQ > non verbal IQ
strengths -
verbal skills, rote verbal material, facial recognition, vocab, grammar, decoding, spelling, procedural learning
deficits -
processing speed, attention, motor skills, memory and learning, math, EF (more attention/motor)
mood: hypersocial
spina bifida quality of life affected by what factors
orthopedic and bladder complications
DWS NP pattern
severe difficulties with upper motor coordination due to cerebellar hypoplasia
ID
premature IVH
children with grades IV IVH with shunted hydrocephalus performed worse than those who are not shunted
idiopathic NPH NP
variable, diffuse pattern
improves with shunting more likely in patients who have not shown severe gait difficulties, dementia or stroke
deficits on motor based tasks, attention, memory, spatial skills, concept formation
employment in congenital hydrocephalus
independent and can work, but underemployed
Transition from childhood to adolescence to adulthood in congenital hydrocephalus is
challenging, and can feel isolating
NPH in older adults is often mistaken for
dementia or PD
diastomyelia
developmental deformity in which the spinal cord is separated into two parts by a rigid or fibrous septum. The deformity is often accompanied by abnormal development of the vertebrae.
hydrocephalus ex vacuo
expansion of the ventricles with no increase in ICP
arrested or compensated hydrocephalus
Ventriculomegaly
enlarged ventricles
meningocele
meninges protrude through the spinal cord
brain of children with meningocele is normal or abnormal
normal, but some may develop aqueductal stenosis
myelomeningocele
protrusion of meninges through incompletely formed spinal cord with a sac containing CSF and CNS material
associated with chiari II malformation
what is the primary cause of hydrocephalus in children
myelomeningocele
children with hydrocephalus secondary to spina bifida myelomeningocele and aqueductal stenosis show what kind of NP?
similar patterns except in motor domain (spina bifida myelomeningocele has MORE difficulty with fine motor skills)
hydrocephalus affects white matter? gray matter?
widespread effects on white matter, gray matter
stretching of white matter axons
compressive effects on cortical structures
spina bifida myelomeningocele and Dandy Walker syndrome both show what impairment?
fine motor skills
In spina bifida myelommeningocele and aqueductal stenosis
verbal skills > than spatial skills
