Developmental Malformations Flashcards
What primarily defines the characteristics of a congenital malformation?
Timing of an insult moreso than the nature of the injury itself
What are the three critical stages of CNS development?
- Neurulation
- Segmentation and Cleavage
- Proliferation
What is anencephaly?
Congenital absence of all or part of the brain as a result of unsuccessful closure of the cephalad
What are two factors that contribute to anencephaly?
Genetic factors and Folic acid deficiency
A child is born and quickly dies within a week. What is your Dx? What is the name of the tissue within the skull? The patient has an absence of spinal cord with overlying vertebral arches and soft tissue. What is this condition called? What test is commonly used to determine the presence of this condition in utero?
Anencephaly; Cerebrovasculosa; Rachinschisis; Alpha-fetoprotein
What is spina bifida? When in the gestational period does an insult normally occur to cause SB?
Failure of neural tube closure in the more caudal regions; 25th to 30th day
Name the spina bifida subtypes from least to most severe.
Spina bifida occulta, meningocele, meningomyelocele, rachischisis
What is the difference between a meningocele and a myelomeningocele?
In both conditions, the meninges extend into a sac, but in a myelomeningocele, the spinal cord is entrapped within the protruding CSF filled sac
A patients spine is shown at autopsy. What is the Dx? What sypmtoms would the patient likely show? What might the mother have been ingesting that led to this condition?
Meningomyelocele; Lower extremity motor and sensory defects, incontinence; Vitamin A/Retinoids
What is your Dx?
Rachischisis
What is dimyelia?
Two spinal cords
What is diastematomyelia?
Axial split of the spinal cord
What is hydromyelia?
Dilation of the central spinal cord canal
What is syringomyelia? What are symptoms?
Formation of a cyst (syrinx) within the spinal cord; Expansion of syrix can destroy parts of spinal cord crossing spinothalamic pathway resulting in loss of pain and thermal sensation
What is Arnold-Chiari Malformation?
Brainstem and Cerebellum are compacted into a shallow bowl-shaped posterior fossa with a low-positioned tentorium
What type of neurological malformation is Arnold-Chiari malformation classified as?
Defect of both neurulation and segmentation because it involves malformation of medulla and cerebellar segmentation and neural tube closure
A patient dies and the brain is shown at autopsy. What is your Dx? What are the specific characterisitcs of this condition shown in the image?
Arnold-Chiari Malformation; Cerebellar vermis herniation below the foramen magnum, Downward displacement of cord causes obex of fourth ventricle to occupy a position below the foramen magnum; Midbrain got a BEAK of the tectum
What is your Dx? Describe the continuum of this condition. What signaling molecule mutation can cause this condition?
Holoprosencephaly; Alobar, lobar, arrhinencephaly; Sonic Hedgehog
A mentally retarded patient presents with anosmia. Dis is what his brain looks like. What is your Dx?
Arrhinencephaly
What is agenesis of the corpus callosum? What conditions are associated? What is the radiographically diagnostic finding of this condition?
Lack of the corpus callosum; Seizures; Bat-wing ventricles; Bat-wing ventricles
What is the most common cause of congenital obstructive hydrocephalus?
Congenital atresia of the Aqueduct of Sylvius
What causes cortical malformations? How is their severity classified?
Defects of Neuroglial Proliferation and Migration; Severity of disruption of gyral pattern
What is the most severe congenital cortial malformation? Describe the cortical appearance.
Lissencephaly; Cortical surface of the cerebral hemispheres are smooth or have imperfectly formed gyri
What is your Dx?
Polymicrogyria
What is your Dx?
Pachygyria
If a fetus’ brain is deprived of blood or oxygen, what can occur? What is this condition called?
Cerebral hemispheres may liquify, leaving a fluid-filled cranial cavity - Hydranencephaly
A fetus experiences intrauterine hypoxia ischemia. What can occur? What happens if infarcted areas undergo resorption?
Periventricular leukomalacia; Multicystic Leukoencephalopathy
What chromasomal abnormalities are incompatible with life? Which three most commonly affect the CNS?
1-12; 13, 15, 21
