Malformations Flashcards
What is the most common cause of neural tube defects?
Folate Deficiency
Where is the most common location of a neural tube defect?
Lumbosacral Region
What is the typical manifestation of spina bifida occulta?
- Usually asymptomatic
- - Non-closure of vertebral arches, identified on X-ray
What is the difference between Meningocele and Myelomeningocele?
Meningocele - lumbosacral protrusion with meninges and dura WITHOUT spinal cord involvement
Myelomeningocele - herniation of the spinal cord through the skin exposing it to the amniotic fluid – degrading and disorganizing neurons
What are the clinical risk factors for Myelomeningocele?
– Folate Antagonists (Valproic Acid)
What are the manifestations of Myelomeningocele?
- Neuro deficits from the exposed area and down, including compromised control of sphincters.
- Should be regularly catheterized to prevent infections
- Seizure Disorder
If an US exam of an unborn baby discovers a pedunculated protrusion in the occipital region, what might be it?
Encephalocele - cranial defect with protrusion of cerebrum/dura. Most commonly occipital, but can be anterior too.
If Alpha-Feto Protein is discovered in the amniotic fluid, then what might be the defect occuring?
Neural Tube Defect
Anencephaly – defect of the calvarium
If an infant is found to have Polymicrogyria, what might have occurred during pregnancy?
– Intrauterine Ischemia
What are the two types of Polymicrogyria?
- Focal – small area of increased gyri and folding in the creases
- Diffuse – global throughout increased folds and gyri
What is the most common cause of abnormal migration of cells in the CNS?
Deletion of LIS1 Gene
If a patient is diagnosed with Miller-Dicker Syndrome, what might be the clinical manifestation?
- Seizures
- MR
- Deletion of Lissencephy I gene
- prominent forehead
- bitemporal hallowing
LIS1 Gene Deletion is most common associated with what?
- Agyria
- - Pachygyria
If MRI finds clefts within the cerebral hemispheres and the patient has marked MR, what might be the diagnosis?
– Schizencephaly
If there is a mutation in the Sonic Hedge Hog gene, what might be a result?
– Arrhinencephaly – abnormal cleavage of the forebrain
Absence of Olfactory Bulbs
Holoprosencephaly
In general terms, the more deformed the face, what does that mean?
The more deformed facial features, the more missing/abnormal internal things.
What is Holoprosencephaly?
– Incomplete Seperation of the Lobes
What are the three types of Holoprosencephaly?
- Alobar – small brain and fused
- Semi-lobar
- Lobar – most normal, but still craniofacial abnormals
If a patient has holoprosencephaly, what might you find clinically?
- Olfactory Aplasia
- Missing or deformed facial bones
- Hydrocephalus
- MR + Seizure disorders
What generally is associated with Corpus Callosum agenesis?
- Missing Singulate Gyri
- - Probst Bundles, fibers going back-front, instead of side to side to connect the hemispheres
If a patient has not singulate gyri or corpus callosum, what might also be occuring?
– Migratory Defect
If a female is born with corpus callosum agenesis with severe MR and intractible seizures, what might be cause?
Aicardi Syndrome – X-linked
If a patient has an accidental finding of a cerebellar tonsillar herniation, what else might be present?
- Syringomyelia, cyst in the spinal cord
- - loss of pain and temperature from those levels
What is the different between Chiari Type 1 and Type 2?
Both have a cerebellar tonsillar herniation, but Type two also involves impingement of the medulla of brain stem, which is much more deadly.
What might be present in Arnold-Chiari malformation?
- Myelomeninocele
- Vit A Deficiency
- Lower Cranial Nerve Defects
- Compromised automatic functions
You notice a patient is missing his vermis of cerebellum, but still has both hemispheres, what do you diagnose him with?
Dandy Walker Malformation
A transverse fluid filled cyst is found within the spinal cord – causing the patient to not have pain or temperature sensations from those levels, what is the etiology?
– Syringomyelia
Cerebral Palsy is caused by?
- Multi-ischemic insults occuring during the fetal / perinatal periods (strokes)
- Nonprogressive neurologic defects
If a premature infant is born and the lungs were not fully developed causing a period of hypoxia, what might the infant be at risk of?
Periventricular Leukomalacia
- white matter necrosis from hypoxia
- destroying of oligodendrocytes (myelinate axons)
If a mother who is pregnant has history of asthma and has a very bad attack that requires her to be intubated due to prolonged hypoxia, what is here child at risk of?
Porencephaly – destruction of grey and white matter in the 3rd trimester due to extensive hypoxia
– Multicystic Encephalopathy
What is the cause of a germinal matrix hemorrhage?
Typically a premature infant who undergoes significant stress during the birthing process has elevated blood pressure which causes hemorrhage in the caudate/thalamus region of the brain (due to not being fully developed yet)
