neonate brain pathology
Terms
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- a congenital anomaly associated with spina bifida in which the cerebellum and brain stem are pulled toward the spinal cord and secondary hydrocephalus develops
- arnold-chiari malformation
- is characterized by displacement of the fourth ventricle and upper medulla into the cervical canal; displacement of the inferior part of the cerebellum through the foramen magnum; defects in the calvarium and spinal column
- arnold chiari malformation
- type __ of arnold chiari is the most common
- 2
- frequently associated with myelomeningocele, hydrocelphalus, dilation of the third ventricle, and absence of the septum pellucidum
- arnold chiari
- sono appears as small cerebellum, absent of the vermis and cistern magnum, low position of the fourth ventricle, with displacement of the cerebellum into the foramen magnum, bat-wing configuration of the frontal horns of the lat. ventricle, hydrocephalus,
- arnold chiari
- caused by abnormal development of prosencephalon; characterized by a grossly abnormal brain in which there is a common large central ventricle; is caused by disturbances in the process of ventral induction very early in life
- holoprosencephaly
- features include a single cerebrum with a single ventricular cavity; absence of cc and frontal horns, and a thin membrane arising from the roof of the third ventricle, which may extend posteriorly forming a supratentorium cyst, cebocephaly or ethmocephaly
- holoprosencephaly
- most severe form of holoprosencephaly; multiple facial anomalies, thalami are fused, no falx, cc, or ihf, third ventricle is absent; single midline crescent shaped ventricle with thin primitive cortex surrounding it
- alobar holoprosencephaly
- single ventricle with pieces of falx and ihf in posterior segment; may be separate occipital and temporal horns; splenium of cc is formed; thalami are partially separated; third ventricle is rudimentary; mild facial anomalies like hypotelorism
- semilobar holoprosencephaly
- has more brain parenchyma than others; least severe form of holo.; complete separation of hemispheres with development of falx and ihf, may be fusion of frontal lobes; septum pellucidum is absent; anterior horns are fused, occipital horns are separated; t
- lobar holoprosencephaly
- abnormal growth which leads to cystic structures in posterior fossa splayng of cerebellum; is a congenital anomaly in which a huge fourth ventricle cyst occupies the area where teh cerebellum usually lies, with secondary dilationof the third and lateral v
- dandy walker malformation
- it may be associated with the following malformations; hydrocephalus, agenesis of the cc, infundibular hamartomas, or brain stem lipomas, holoprosencephaly
- dandy walker malformation
- sono appears there is an absence of the cerebellar vermis, cystic changes in the fourth ventricle with the development of a large cyst in the posterior fossa, and hydrocephalus; enlarged posterior fossa, elevation of the tentorium which is being pushed fo
- dandy walker malformation
- considered a variant when there is an enlarged cistern magna in the presence of a normal or hypoplastic vermis
- dandy walker variant
- no connector between the two hemispheres; is a condition in which the fibers of the cc cross from side to side on a glial sling; the cc is absent in severe holoprosencephaly; may be associated with arnold chiari and hydrocephalus
- agenesis of cc
- sono is distinguished by narrow frontal horns, as well as marked separation of the anterior horns and bodies of the lateral ventricles associated with widening of the occipital horns and third ventricle; elevation of third ventricle which leads to obstruc
- agenesis of corpus callosum
- complicates SEV-IVH in approximately 15-25% of infants; are a severe complication, because they indicate that the brain parenchyma has been destroyed; severe; grade 4 spreads to cerebrum
- intraparenchymal hemorrhage
- sono appears as very echogenic zones in the white matter adjacent to the lateral ventricles; should see adjacent to ventricular system;echogenic areas in white matter may correspond to IPH, hemorrhagic infarction, or extensive periventricualr leukomalacia
- intrapaenchymal hemorrhage
- ___ follow the same evolution as intraventricular clots; a few days after the acute bleeding, the clots become cystic (break down) and are reabsorbed completely in 3 or 4 weeks, leaving a cavity communicating with the lateral ventricle (porencephalic cyst
- intraparenchymal clots
- have germinal matrix around cerebellum that closes at 40 weeks gestation so can happen in preterm babies; four categories; in premature neonates, there are areas of germinal matrix located around the fourth ventricle in this
- intracerebellar hemorrhage
- the __ has the same vulnerability to hemmorrhage as the telencephalic germinal matrix which is at at the caudo-thalamic groove
- intracerebellar hemorrhage
- sono becomes cystic with time, leaving cavitary lesions int he cerebellar hemispheres; echogenic like others but different ecause becomes anechoic with time
- intracerebellar hemorrhage
- what are the four categories of intracerebellar hemorrhage
- primary, venous infarction, traumatic laceration resulting from occipital diastatsis, and extension to the cerebellum of a large SEH-IVH
- too superficial to see sonographically; are better evaluated via CT because these lesions are located peripherally along the surface of the brain, they are often not adequately visualized by ultrasound
- epidural hemorrhage and subdural collection
- sono it appears as non-echogenic spaces between the echogeic calvarium and cortex; are also seen as echogenic formations located immediately underneath the calvarium
- epidural hemorrhage and subdural collection
- is a common complication of purulent meningitis in newborn infants; purulent material in ventricular system usually from meningitis that might have been caused by ventriculoperitoneal shunt; probably is caused by hematogeneous spread of the infection of t
- ventriculitis
- the presence of a foreign body int eh ventricular cavity, such as a catheter from a ventriculoperitoneal shunt, may provide a nidus for persistent infection of the ventricular cavities
- ventriculitis
- sono the first stage is seen in ultrasound as very thin septations extending from the walls of the lateral ventricles; the septa become thicker and lead to multilocular hydrocephalus and extensive disorganization of the brian anatomy; sequential studies n
- ventriculitis
- occurs when the subependymal becomes thickened and hyperechoic as a result of irritation from hemorrhage within the ventricle; usually results from ventriculitis
- ependymitis
- refers to any condition with enlargement of the ventricular system is caused by an imbalance between production and reabsorption of csf; is caused by the obstruction of csf; the earlier it occurs, the greater the enlargement of the head; this dilation res
- congenital hydrocephalus
- what are the three kinds of hydrocephalus
- communicating, non-communicating, papilloma of the choroid plexus
- if hydrocephalus is severe they put a shunt in that drains fluid to the ___
- peritoneal
- the most comon cause of congenital hydrocephalus is __
- aqueductal stenosis (which is considered non-communicating in utero but once the baby is born then it becomes "congenital"
- the aqueduct of sylvius is narrowed or replace by multiple small channels with blind ends; the tech should look for the blunting of the lateral angles of the lateral ventricles
- congenital hydrocephalus
- is characterized by interferenc ein the circulation of csf within the ventricular system itself, causing subsequent enlargement of the ventricular cavities proximal to the obstruction
- obstructive hydrocephalus (non-communicating/congenital)
- may be caused for example by subarachnoid cyst or foramen of luschka; the csf pathways are open within the ventricular system but there is decreased absorption of csf; not within ventricular system but within subarachnoid space; absorption of csf can be i
- communicant hydrocephalus
- sono it can be dx when an infant is born with widening of the lateral and third ventricles and a normal-sized fourth ventricle; if the enlargement is great the posterior fossa is smaller than usual, and the cerebellum is desplaced toward the occipital bon
- hydrocephalus
- __ leads to thinning of the cerebrum and destroying of brain tissue
- hydrocephalus
- ___ covers all parts of the brain so cysts can be in any region or location
- subarachnoid space
- are lined by arachnoid tissue and contain csf; may be located in teh infratentorial or supratentorial compartments; when they are in the posterior fossa they are associated with a normal vermis and normal fourth ventricle, which differentiates it from dan
- subarachnoid cysts
- in the ___ compartment, subarachnoid cysts usually arise from the suprasellar or quadrigeminal plate convexities
- supratentorial
- the most frequent location for subarachnoid cysts are these three
- IHF, suprasellar region, and cerebral convexities
- means area right in front of third ventricle
- suprasellar region aka chiasmatic
- these can be symptomatic secondary to cerebral compression of hydrocephalus, or may be totally asymptomatic especially if small
- subarachnoid cyst
- sono it appears as non-echogenic cystic structures arising from the quadrigeminal plate cistern or suprasellar region; sagittal studies are useful to determine the location and size; sequential studies should be obtained in infants with this complication,
- subarachnoid cysts
- usually because of premature birth; occur at caudo-thalamic groove aka germinal matrix becaused of the fragile capillaries in that particular region; are the most common hemorrhagic lesions in preterm newborn infants
- subependymal intraventricular hemorrhage (seh/ivh)
- suh/ivh affect __ to __% of infants who are born at less than 34 weeks gestation
- 30-50%
- they are developmental disease because they originate in teh subependymal germinal matrix; are caused by capillary bleeding in the germinal matrix; the most frequent location is at the thalamiccaudate groove; if it pushes into ventricular system then it b
- SEH
- full term baby hemorrhage is in __ usually
- choroid plexus
- if bleeding continues, the hemorrhage enlarges, pushing the ependyma into the __ cavity, which then can become completely occluded by the SEH; eventually large SEH rupture though the ependyma and form the IVH
- ventricular
- are easily detected with ultrasound as very echodense structures, because fluid and clotted blood have higher acoustic impedance than brain parenchyma and CSF
- SEH and IVH
- ___appear as echodense structures inside the anechoic ventricular cavities; depending on the amount of blood, the ventricle can become full and dilated; hemorrhage in brain progresses slowly. subquently the __ may obstruct the circulation and absorption
- IVH; SEH
- the ventricular size is measured in teh sagittal plane which is the height of the bodies at mid __ and axial plane which is the width of teh __ at the level of the choroid plexus
- thalamus, atrium
- based on these measurements ventricular dilation may be classified as follows: (3)
- mild, moderate, and large dilation
- ventricular dilation: mild is __ to __ mm; moderate is __ to __ mm and large dilation is __ to __ mm
- 8-10, 11-14, greater than 14
- after the hemorrhage has occured, the blood spreads following the csf pathways reaching hte fourth ventricles and eventually teh cisterns in the posterior fossa with the development of the ___ which may cause reabsorption and production problems of csf;
- subarachnoid hemorrhage, arachnoiditis, CSF
- __ ventricular dilation develps as a consequence of imbalance of CSF from a hemorrhage
- posthemorrhagic
- in the ventricular dilation is progressive from a hemorrhage, the patient is considered to have ___ which occurs in 35% of infants with large hemorrhages
- posthemorrhagic hydrocephalus
- usually mild to moderate ventricular dilation resolves spontaneously; however placement of a __ may be necessary for severely dilated ventricles; mild small hydrocephalus can be reabsorbed on its own
- ventriculoperitoneal shunt
- how many grades are there for sono evaluation of neonatal brain lesion
- 4
- grade 1: mortalitiy is __ %; most cases resolve completely with good potential for normal __; confined to __ matrix; seen as moderate to high echogenic mass at ___ located at the head of the caudate nucleus
- 15%, neurological development, subependymal, caudothalamic groove
- grade 2: mortality is __ %; most cases resolve completely with good potential for normal ___; IVH without __ dilation; clot become ___ centrally and more well-defined; third and fourth ventrical may appear ___
- 20%, neurological development; ventricular dilation; anechoic; prominent
- grade 3: mortality is __ %; associated with some __ of neurological development; IVH with ventricular dilation (__ to __ mm); ___ clot may adhere to ventricle wall and appears as a dependent echo within ventricle
- 40%; degree; 8-14 mm; echogenic
- grade 4: mortality is __%; assocatied with __; IVH with ___ (in cerebrum); echogenic mass that undergoes various ___ stages, midline structures and ventricles ___ and ___ cyst may develop
- 60%; neurological development; intraparenchymal hemorrhage; reabsorption; displace; porencephalic
- are cerebral injuries and is a frequent complication of sick newborn infants; five major types have been described; means areas of lossed blood supply and decreased oxygen
- ischemic-hypoxic lesion
- what are the five types of ischemic-hypoxic lesions and what is the most important one
- white matter necrosis aka periventricular leukomalacia (most important), focal brain necrosis ,selective neuronal necrosis, status marmoratus, parasagittal cerebral injury
- ultrasound is not a very precise technique to dx this pathology; ultrasound may show areas of increased echogenicity in the subcortical and deep white matter and the basal ganglia; look for areas of bright and cystic lesion; however, echodensities are not
- ischemic-hypoxic lesion
- ultrasound is useful in dx multifocal white matter necrosis and focal ischemic lesions. they are bright at first and will show ___ lesions in a followup
- anechoic
- this is the most frequet lesion in teh immature brain; is associated with anomalous myelination of the immature brain, as well as abnormal neurologic development, including cerebral palsy; probably the most important cause of abnormal neurodevelopmental s
- perventricular leukomalacia (an ischemic-hypoxic lesion)
- early in the chronic stage multiple cavities develop in the necrotic white matter adjacent to the lateral walls of the frontal horns, body, atria, and occipital horns of the lateral ventricles; these lesions are frequently located in the lateral wall of t
- periventricular leukomalacia
- eventually the cavities resolve, leaving gliotic scars and diffuse cerebral atrophy; necrotic lesions with only microscopic cavities also may lead to cerebral atrophy; look for breakdown in parenchyma
- periventricular leukomalacia
- sonographically, the acute stage of this pathology is characterized by highly echogenic areas in the cerebral white matter superior and lateral to the frontal horns, bodies, atria, and occipital horns of the lateral ventricles; echodense areas are present
- white matter necrosis
- echodensities may be assoicated only with congestion and microhemorrhages without ___. if the necrosis was extensive, brain atrophy may be the only indication that ___ occurred during the perinatal period
- necrosis, wmn
- in wmn, ultrasound is useful to dx the ___ phase of the chronic stage; this phase is identified by an enlarged subarachnoid space, widened interhemispheric fissure, and persistent ventricular dilation in an infant with a normal or small head circumference
- atrophic
- can occur in premature and or term babies; cerebral/brain edema makes it all echogenic; decreased brain parenchyma and enlargement of the ventricular system; occur within the distribution of large arteries
- focal brain necrosis
- this complication is present in term and preterm babies but it is infrequent under 30 weeks gestation; vascular maldevelopment, asphyxia or hypoxia, embolism from the placenta, most commonly TORCH, infectious diseases, thromboembolism secondary to dissemi
- focal brain necrosis
- these insults may occur prenatally or early postnatal life leading subsequently to the dissolution (liquification) of the cerebral tissues and formation of cavitary lesion;
- focal brain necrosis
- the tern __ which is also considered to be focal brain necrosis, is used to describe a single cavity, multicystic encephalomalacia for multiple cavities, and hydranencephaly for a large single cavity with entire disappearance of the cerebral hemispheres
- porencephaly
- sono the images observed with ultrasound in these injuries are very echogenic localized lesions within the distribution of the major vessel; the echodense lesions are considered to correspond to cerebral infarction; after several days echolucencies appear
- focal brain necrosis