CNS malformations Flashcards
What are Neural tube defects?
- congenital
- abnormal development of brain and/or spinal cord
- failure of embryonic neural tube to close
- mom folate deficiency
- supplement mom with folic acid to reduce NTD by 70%
- common, 1 in 1000 preg./year
- foetal death
- reduces prevalence of neural defects at birth
What are the types of Neural tube defects?
• Anencephaly • Encephalocele • Spina bifida -occulta -meningocele -myelomeningocele
List cranial deformities
- acrania
- craniosynostosis
- microcephaly
- congenital hydrocephalus
What is acrania?
cranial vault nearly completely absent
What is craniosynostosis?
premature closure of one or more of the cranial sutures
What is microcephaly?
significant decrease in size of brain and skull
What is congenital hydrocephalus?
increase in CSF volume (from many causes)
What is hydrocephalus?
- excess fluid in cranial vault, or subarachnoid space
- caused by anything that: decreases reabsorption of CSF, increases CSF production, obstruction in ventricular system
- congenital (aqueduct stenosis, insults in utero) or acquired (infection, neoplasms, trauma)
Compare non-communicating to communicating hydrocephalus ?
Non-communicating: obstruction in ventricular system
Communicating: impaired absorption of CSF
What is Arnold-Chiari Type 1? *just know basics
- herniation of elongated segment of inferior cerebellar vermis and paranormal folia through foramen magnum
- asymptomatic or complication -> death
- hydrocephalus
What is Arnold Chiari Type 11? *just know basics
- posterior cranial fossa abnormal shallow
- caudal herniation of medulla and part of cerebellar vermis through foramen magnum
- hydrocephalus if complication
What is the pathophysiology of hydrocephalus (in an adult) ?
• obstruction to CSF flow (in ventricular system, or arachnoid vili)
- > increase volume CSF
- > dilation of ventricular system proximal to obstruction
- > increased pressure on brain
- > atrophy of cerebral cortex and degeneration of white matter
- > increase ICP
- > features of high ICP and
What is the pathophysiology of hydrocephalus in a child?
• increases pressure on brain
- > enlargement of head
- > fontanelles enlarge, full, bulging (scalp skin thin and shiny, prominent surface veins, frontal bossing)
- > ICP increases
- > features of high ICP
What is the flow of CSF?
Lat. ventricle choroid plexus
- > interventricular foramen
- > 3rd ventricle (+ CSF from plexus)
- > aqueduct -> 4th ventricle (+ CSF from plexus)
- > lateral median aperture
- > subarachnoid space
- > arachnoid vili of dural venous sinuses
- > venous blood