SDL-8 Pediatric Pathology Flashcards
Anencephaly
A defect in anterior neuropore closure. The initial point of fusion to the posterior neuropore is normal while no fusion occurs rostral to the brainstem. There are no cerebral hemispheres. The insult occurs prior to 24 days gestation. Some infants are liveborn but succumb early.
Encephalocoele
An outpouching of neural tissue which results when anterior neural tube closure occurs only partially. Usually occipital. Occurs by day 25. Maternal hyperthermia between day 20-25 may be a cause. Both fevers and saunas and/or hot tubs are culprits.
Myelomeningocele
Partial failure of posterior neural tube closure. Most occur over the lumbar area (last region to close). Exposed neural elements are not covered by bone and may or may not be covered by a sac of skin. Occurs by day 27. Incidence up to 5/1000 live births. Hydrocephalus occurs in most. Associated problems vary with level of defect but include loss of sensory and motor function, sphincter dysfunction, rapidly enlarging head circumference.
Arnold-Chiari malformation
Hydrocephalus associated with myelomeningocele. Various degrees, may consist of inferior displacement of posterior fossa structures and bony defects in the foramen magnum and upper cervical vertebra.
Holoprosencephaly
Failure of cleavage of the forebrain (telencephalon and diencephalon) into paired hemispheres.
The face may appear unusual with a single eye (cyclopia) and a single nostril (cebocephaly).
Caused by chromosomal disorders, diabetic mothers and genetic syndromes.
Absence of the gyri recti is known as ______________.
Olfactory aplasia
Absence of the cingulate gyrus is known as _____________.
Agenesis of the corpus callosum
Agenesis of the corpus callosum
May be complete or partial absence of the cingulate gyrus.
Most notably causes a “batwing” malformation of the lateral ventricles.
Patients with an enlarged posterior fossa and absent or partially absent cerebellar vermis may be described as having _____________________.
Dandy-Walker malformation
_______________ is the underdevelopment or abnormally small size of the brain. This may be attributed to Down syndrome, Fragile X syndrome, fetal alcohol syndrome, phenylketonuria, intrauterine infections during pregnancy, or exposure to radiation while child-bearing.
Microcephaly
Polymicrogyri (polygyri)
A brain that has regions with too many small gyri. Histology may reveal that many more additional gyri are present than can be detected grossly.
Lissencephaly (agyria)
Smooth brain with few or no gyri
Heterotopias
The least severe of migration defects, referring to normal islands of tissue deposited in the wrong place.
Schizencephaly
Cleft brain, sometimes bilaterally. If the defect is small, and does not extend long distances along the dorsoventral axis, then the term “porencephaly” can be used.
