CH 3 Cranial and Spinal Pathology Flashcards
3 Stages of brain development:
Cytogenesis: formation of molecules into cells
Histogenesis: formation of cells into tissue
Organogenesis: development of tissues into organs
Abnormalities occurring during Histogenesis can cause:
Histogenesis: cells into tissues
Tuberous Sclerosis
Neurofibromatosis
Sturge-Webers disease
Vascular lesions:
Tuberous Sclerosis
{Latin: tuber (swelling), Greek: skleros(hard)} multi-system genetic disease; causes tumors to grow in brain and other parts of body; renal and cardio rhabdomyosarcomas. Pathologically: thick, firm and pale gyri in brain.
Neurofibromatosis:
benign tumors which can put pressure on spinal nerve roots
Sturge-Weber’s disease:
port wine stain around forehead or eye area; brain abnormalities on the same side of the brain as the face lesion; seizures and vision abnormalities.
Vascular lesions:
vein of Galen malformation, AVM’s
Abnormalities occurring during Organogenesis can cause:
Organogenesis-tissues into organs
Neural tube closure (3-4 weeks)-
cranioschisis (dysraphism): anecephaly, encephalocele, myelomeningocele, chiari malformations, dandy-walker malformations, agenesis of corpus callosum, teratomas
Diverticulation (5-6 weeks)-
Holoprosencephaly, septo-optic dysplasia, aventricular cerebrum
Neuronal proliferation (2-4 months)- Microcephaly and Macrocephaly (megalocephaly)
Neuronal migration (3-6 months)-
Neurons migrate to specific locations in CNS
Lissencephaly, Schizencephaly, polymicrogyria
Organization (6 mo - years)
proper alignment, orientation and layering of neurons of the cerebral cortex.
Myelination (birth- years)
laying down of the myelin membrane, the sheath covering the nerves.
Intracranial hemorrhage
is the most common and serious cause of neurological morbidity and mortality in the newborn. Most intracranial hemorrhages occur within the first 3 days of life, and rarely occur in utero. The majority of ICH’s occur due to hypoxic-ischemic events.
Clinical symptoms of Intracranial hemorrhage (ICH)
RDS (repiratory distress syndrome)
decreased hematocrit
less than 1200 grams birth weight
trauma at delivery
SGA(small gestational age), maternal pre-eclampsia, asphyxia, antepartum hemorrhage, and male neonate.
ICH (intracranial hemorrhage) sono characteristics:
Acute: 1-7 days, increased echogenicity
Subacute: 7-14 days, moderately echogenic with a central sonolucency
Chronic: 14 days-2 mo, moderately echogenic with retracting hematoma
2-6 mo there may be total sonolucency
SEH (subependymal germinal matrix hemorrhage)
SEH/GMH most common type of hemorrhage in premature infants; more common in infants less than 32 weeks and less that 1200 grams. unusual after 34 weeks gestation.
50% of GMH occur in 1st day of life, and correlates with extreme prematurity and birth asphyxia.
Germinal matrix area is the most common site of SEH, due to fragile network of capillaries in this area. fluctuations in cerebral blood pressure and flow can rupture germinal matrix vessels or lead to infarct.
Germinal matrix area:
becomes vascular by 36 weeks due to cortical migration of the neural cells and involution of the germinal matrix.
*the most common site of a GMH is at the junction of the caudate nucleus and choroid plexus.
Intraventricular hemorrhage (IVH)
IVH is an extension into the ventricle from the SEH.
The ventricle may be dilated.
usually caused by germinal bleed into lateral ventricle
Choroid Plexus Hemorrhage
If and IVH is seen without a SEH, the hemorrhage probally originates from the choroid plexus.
These are usually found in term infants and are difficult to diagnose.
Intraparenchymal hemorrhage
most extend into the frontal or parietal lobes (temporal lobe is rare) and occur as a result of an extension of a SEH.
an IPH ususally resolves leaving a porencephalic cyst.
IPH in a term neonate is usually due to an interuterine infarct or neonatal stroke.
IPH may occur on it’s own and have the worse outcome.
Grades of Intracranial Hemorrhage:
I. Isolated SEH (germinal matrix region)
II. SEH or Choroid plexus hemorrhage with IVH; no ventricular dilatation.
III. SEH or Choroid plexus hemorrhage with IVH, ventricular dilatation
IV. SEH or Choroid plexus hemorrhage with IVH and IPH
Other types of Intracranial Hemorrhages:
DIFFUSE CEREBRAL HEMORRHAGE- in the white matter is caused by infarction. usually originates lateral to frontal horns and bodies of the lat vent. Intraventricular hemorrhage is not seen with these cases. Diffuse cerebral hemorrhage results in PVL.
ISOLATED CORTICAL HEMORRHAGES- unusual. thought to be caused by coagulation disorders, A-V malformations, tumors, abscesses or trauma.
INTRA-CEREBELLAR HEMORRHAGES- uncommon but fatal due to pressure on the brain stem and occiput. caused by trauma during a difficult delivery and more common in preemies than term infants.
Extracerebral hemorrhages (extra-axial hemorrhages)
Subdural hemorrhage subarachnoid hemorrhage Epidural hematomas/hemorrhage Posterior fossa sub-dural hematoma subperiosteal hematoma (cephalohematoma)
Subdural hemorrhages
occur after trauma. may result from: tearing of the veins between the brain and dural sinus, the tearing of the dural fold where it extends into the venous sinusoids, or laceration of a sinus by a fractured or separated skull. blood collects between dura and brain.
More common in term infants than preemies and often due to forceps or vacuum assistance during delivery.
Sonographically: appear as hyperechoic fluid collections surrounding the brain and may be either unilateral or bilateral, generally difficult to see on ultrasound.
Subarachnoid hemorrhages
more common in preemies than term infants. Usually due to hypoxia or asphyxia. Trauma at delivery is usual cause in term infants. Difficult to see due to echogenic nature of hemorrhage and surface of brain.
Large SAH may be seen as fluid over the cerebral convexities or as widened echogenic sylvian fissure.
Clinically silent and of little prognostic importance.
Epidural hematomas/hemorrhages
occur between dura mater and skull. due to trauma and of arterial origin under high pressure.
Lead to accumulation of arterial blood between the dura and skull. Best seen with CT and occur in term infants.
Sonographically: appear as hyperechoic fluid collections surrounding the brain either unilateral or bilateral.
Posterior Fossa Sub-dural Hematomas
rare and often fatal. Occur as a result of “shaken baby” syndrome. Usually seen on CT
Subperiosteal hematoma (cephalohematoma)
complication of childbirth. hematoma forms under the scalp of babies delivered with forceps or vacuum.
Feels “squishy”
can be a sign of skull fracture
between skull/skin
Types of hemorrhages occur:
Preemies
Term
Any
PREEMIES-
SEH/IVH/IPH
intracerebellar - trauma
Subarachnoid - trauma
TERM INFANTS-
Subdural - trauma
Epidural - trauma
IVH/IPH
ANY INFANT- Diffuse cerebral hematoma - infarct Isolated cortical - vascular problems, tumors, abscesses, trauma Subperiosteal - forceps/vacuum posterior fossa subdural _ "shaken baby"
Periventricular Leukomalacia (PVL) (Leuc - white, Malacia- softening)
“brain rot” HIE- hypoxic ischemic encephalopathy
white matter disease affecting the periventricular zones. most severe and frequent cause of cerebral palsy in children surviving pre-term birth. more than 50% off infants with PVL or grade IV hemorrhages develop cerebral palsy
risk factors of PVL: gestational age of 27-30 weeks, PROM 12 hrs before delivery and intrauterine infections
PVL most common in infants weighing less than 1000 grams. softening of white matter beside the lateral ventricles due to infarction occurs causing PVL due to ischemic infarction. Premature infants this white matter area is a watershed zone between the deep and superficial vessels.
Periventricular Leukomalacia (PVL) appearance:
initially appears hyperechoic in the frontal horn region and in the periventricular tissue.
The echogenicity exceeds that of the choroid plexus in PVL.
These hyperechoic regions turn into cystic areas, which usually communicate with the ventricles, as the destroyed white matter becomes liquefied in approximately 1-3 weeks after insult “swiss cheese”
Infants with PVL may have sever neurological disorders including:
Cerebral Palsy
Developmental delays
Quadriplegia
Diplegia - Paralysis affecting one part of the body and the corresponding part on the other side: usually both legs
Cystic Encephalomalacia
irregular cystic area in the parenchyma of the brain, which may be caused by infection, infarction (due to hypotension) or trauma and can be focal or diffuse.
The presence of glial septations distinguishes this anomaly from an area of porencephaly and indicates that the injury occurred either late gestation or neonatal period. rather than PVL
Sonographically: irregular, septated cavities are seen and calcification may be present.
Cerebral ischemia
lack of blood in an area of the body due to mechanical obstruction or functional constriction of blood vessels.
Cerebral infarction
formation of an area of necrosis in tissue caused by obstruction of the artery supplying the area.
Causes: anoxia, shock, dehydration, hyperviscosity of blood, and hemorrhage.
Complications of an anoxic brain injury (lack of oxygen)
diffuse cerebral edema
decreased ventricular size
echogenic cerebral tissue
anoxic brain injury may lead to multiple areas of infarction and necrosis.
Acute cerebral infarction
hyperechogenicity of the brain and abnormal sulci and gyri are seen along with edema.
vascular pulsations disappear, but may return in the more chronic stages, when the brain becomes less edematous.
Hydrancephay
congenital anomaly of unknow etiology, thought to be caused by bilateral ICA occlusions during fetal development. associated with Trisomy 13 and 18
primary agenesis of the neural wall occurs and the occlusions cause necrosis of cerebral hemispheres.
Total or near absence of the cerebral hemispheres is seen with normal skull and meniges present.
Cerebellum, midbrain, brainstem and basal ganglia are intact and usually surrounded by fluid. can see falx.
Hydrancephay sonographically:
macrocephaly and a large echo-free area within the cranial vault surrounding the midbrain and basal ganglia is seen.
occasionally absent falx. variable presence of a 3rd ventricle.
Tentorium is seen separating a normal posterior fossa from the anterior and middle cranial fossa.
ECMO (extracorporeal membrane oxygenation)
provides both cardiac and respiratory support to patients with severely damaged heart, lungs or both. Similar to heart/lung machines. ECMO used most often in newborns and young children to help the lungs and heart rest and recover. *usually diaphragmatic hernia, aspiration of meconium.
** used when there is not alternative for treatment.
How does ECMO work?
Blood flows into the ECMO circuit from the jugular or carotid and jugular, to receive oxygen and remove wastes. the blood is then returned to the patient when oxygen is added and CO2 removed. Continuous process. The ECMO circuit imitates the gas exchange process of the lungs; removes carbon dioxide and adds oxygen.
After ECMO patients still need ventilation assistance.
Patients receive anticoagulant drugs while on ECMO
serial cranial ultrasound alert dr to hypoxic ischemia, cerebral edema, encephalomalacia, or ICH due to ECMO.
What is the biggest risk of ECMO?
bleeding is the biggest risk due to blood thinners given. The greates risk for infants is inracranial hemorrhage.
The side effects of ECMO include: blood cloths, hemorrhgae and infection at the cannula site.
2 types of ECMO
Venoarterial (V-A)- support heart and lungs.
Used in patients with blood pressure of heart functioning problems in addition to respiratory problems. Requires the insertion of 2 cannulas: one in the jugular and one in the carotid artery.
Venovenous (V-V) support lungs only.
cannula placed in the jugular vein.
ECMO uses in the newborn:
to support or replace and infants underdeveloped failing lungs by providing oxygena dn removing CO2 waste products so the lungs can rest.
Selection criteria for newborn ECMO:
>34 weeks gestation >2000 grams birth weight No major ICH or coagulation pathology < 10-14 days on ventilator reversible lung injury must be present No lethal malformations No major untreatable cardiac malformations Failure of any previous maximum medical therapy
approx. 75% effective in saving a newborns life.
typically remain on ECMO from 3-7 days (diaph hernia longer) 21 days max.
ECMO used on infants with:
Children:
Meconium aspiration pulmonary hypertension pneumonia group B strep sepsis respiratory distress syndrome (RDS) congenital diaph hernia
used on children for: heart failure, pneumonia, severe infections, respiratory failure caused by trauma (drowning, aspiration)
Mortality rate for children high, about 2-5% success rate.
ECMO complications:
bleeding infection emboli pneumothorax vascular disruptions
Hydrocephalus (hydro= water, cephalus= brain)
accumulation of CSF in the brain which leads to increased intracranial pressure and head size.
CSF obstuction can occur within or outside of the ventricular system. More common in children less than 2 years. occurs 1 in 500 births.
when CSF is blocked, the ventricles dilate and pressure is put on the brain. may lead to irreversible brain damage.
can be communicating or non-communicating and both may be acquired or congenital.
** hydrocephalus is first seen in the occipital horn of the lateral ventricle then moves to body and anterior horn.
CT modality of choice for older children and adults, ultrasound for prenatally, neonates, and young infants.
Causes of hydrocephalus:
impaired CSF reabsorption
excessive CSF production
flow obstructions
post-traumatic or post-inflamatory lesions
congenital malformations
**most common IVH - clot can block flow
**overproduction of CSF is the least common cause of hydrocephalus- this would be due to choroid plexus papilloma.
Communicating hydrocephalus (non-obstructive)
caused by impaired CSF resorption in the absence of CSF flow obstruction between the ventricles and subarachnoid space. May be due to functional impairment of the arachnoid granulations.
born without, or not working
causes dilatation of all 4 ventricles.
Causes of communication hydrocephalus:
subarachnoid or intraventricular hemorrhage
meningitis
chiari malformation
congenital absence of arachnoid granulations
Non-communicating hydrocehpalus ( obstructive hydrocephalus)
external compression or and intraventricular obstruction of the normal CSF flow.
It causes dilation of only the ventricle or ventricles directly affected by the obstruction.
Location of non-communicating hydrocephalus obstructions:
FOURTH VENTRICLE- would cause dilataion of the lateral vents, 3rd vent and aqueduct of sylvius
FORAMEN OF MONRO- causes dilatation of one or both lateral vents
AQUEDUCT OF SYLVIUS- dilatation of the later vents and 3rd vent
FORAMINA OF LUSCHKA AND MAGENDIE- dandy-walker syndrome
SUB-ARACHNOID SPACE- due to inflammatory processes which would lead to dilatation of all ventricles
Congenital hydrocephalus may be due to:
dandy-walker syndrome, chiari malformations, or atresia/stenosis of the aqueduct.
Acquired hydrocephalus may be due to:
IVH, infections, meningitis, brain tumors, head trauma, or subarachnoidintraparenchymal hemorrhages.
acquired hydrocephalus is usually painful.
Ventriculomegally:
dilation of ventricle WITHOUT increase in intracranial pressure of head size.
Lateral ventricular atrium width greater than 10mm
Mild-moderate 10 to 15mm, severe greater than 15mm
Causes of Ventriculomegaly:
neural tube defects (spinabifida, encephalocele), dandy-walker malformations, agenesis of the corpus callosum, lissencephaly, aqueduct of sulvius obstruction due to inflammatory process (CMV/parvovirus) isolated defect or x-linked recessive condition, neoplasms, arachnoid cysts.
Inflamatory responses and hemorrhage, as well as vein of Galen aneurysms can also cause ventriculomegaly. Ventriculomegaly is seen in holoprosencephaly, porencephaly, hydrancephaly, spina bifida and microcephaly.
Difference between ventriculomegaly and hydrocephaly:
ventriculomegaly: increased ventricular size WITHOUT increase in head sized or intracranial pressure.
hydrocephalus: increased ventricular size WITH increased head size and increased intracranial pressure.
Ventricular shunts:
device placed to drained excess CSF from dilated ventricle.
Ventriculoperitoneal shunts (v-p shunts)
drain CSF into abdominal cavity.
One way flow and regulates the amount of CSF draining into peritoneum.
one end of shunt is placed in ventricle through the occipital horn with tip anterior to foramen of monro, distal portion placed in peritoneal cavity.
When scanning abdomen of child with v-p shunt with increased head size or fever look for:
abscess in abdomen in region of distal end of shunt or pseudocyst, which may block shunt.
reverb artifact at end of shunt.
Infant with v-p shunt (ventriculo-peritoneal) with bulging fontanelles place in ______ position
semi-fowler position - head and knees elevated
Post op evaluation of VP shunt position:
complications: subdural collections and cyst enlargement
pre- and post-op comparison of corticla thickness, lateral ventricle height measurement, third ventricle width, venticular ratio.
most follow ups done with CT
Correct placement of VP shunt:
is in the anterior horn of the lateral ventricles, anterior to the Foramen of Monro.
Shunt must be placed in area that has no choroid plexus. ( could cause shunt obstruction)
Midline shift in brain:
brain tumors
cysts
any type of hemorrhage
Edema
increased echogenicity of the brain is seen and decreased ventricle size ( the ventricles appear more “slit-like”) poorly defined sulci.
Periventricular areas and cerebellum are usually spared with acute near total intrauterine asphxia in newborns.
hypoxic ischemic brain damage may cause diffuse cerebral edema.
Ventriculitis
infection of the ventricles which is associated with encephalitis.
ventricles become dilated and may contain septa and debris.
inflammation extends to the choroid plexus and ependymal lining. the choroid becomes misshapen and the walls of the ventricle appear thickened.
subependymal cysts
cysts seen in the lining of the ventricles. usually result of germinal matrix hemorrhage. can also ve caused by infections.
If small, may be asymptomatic (not blocking)
Intracranial infections
inflammatory lesions may be congenital or acquired.
Intracranial infections cause calcs in the brain that appear as echogenic foci, without shadowing.
ventricular dilatation, echogenic brain parenchyma, and encephalomalacia (encephalo- brain, malacia - softening)
TORCH
congenital inflammatory lesions.
- Toxoplasmosis
- Other infections -syphilis, varicella-zoster( chicken pox, herpes), parvovirus B19(fith disease)
- Rubella
- CMV
- Herpes simplex II
Striatal densities/ vasculopathy
striatal arteries are branches of the MCA. they course upward towards the anterior fontanelle. These vessels are prominent in fetal life; they perfuse the germinal matrix area. * put color on, they will light up
may be seen due to: toxoplasmosis, asphyxia, GMH, CMV, bacterial menigitis, trisomies 13 and 21, rubella
Hemophilus influenza
can cause menigitis or menigioencephalitis.
Edema and inflammation of the brain may occur, which can then lead to brain abscesses.
Meningitis
can cause granulomas and obstructive hydrocephalus in the brain.
occasionally a subdural lfuid collection may be seen.
abscess fomation is common and venous sinus thrombosis may occur.
ventriculitis is often a complication
Brain abscesses
are rare and usually a complicatio of sinus infections or penetrating trauma, they may be associated with congenital heart disease.
usually associated with ventriculitis and encephalitis.
may appear lobulated or cystic-like with non-homogenous echogenic material.
Brain atrophy
wasting away of the brain.
May be caused by: anoxia hemorrhage stroke maternal infections maternal diabetes traumatic brain injury complications of pre-term birth which lead to cerebral palsy
Intracranial cysts
fluid-filled cavities within or adjacent to the brain.
include: porencephalic, arachnoid, ventricular, choroid plexus, neoplastic
Porencephalic cyst
caused by brain necrosis adjacent to ventricle with the development of a communication.
result of PVL (periventricular leukomalacia) caused by hemorrhage, infection or infarction.
Arachnoid cyst
uncommon benign cystic lesions with lie in the subarachnoid space and contain CSF. They do NOT communicate with the ventricles or arachnoid space.
CSF is usually trapped in the cistern areas posterior to the 3rd ventricle and the posterior fossa. If located midline, may be associated with hydrocephalus.
sonographically: fluid collection in cerebral cortex or posterior fossa is seen. Anechoic and have a well-defined smooth margin. dilatated venticles are commonly seen.
Ventricular cysts
occur when there is entrapment of just one part of the ventricular system.
Choroid plexus cysts
common and asymptomatic, usually bilateral and less that 2mm in size. Contain CSF and cellular debris
Neoplastic cysts
include Cystic astrocytomas and teratomas
Intracranial mass lesions
- Congenital teratomas (most common present at birth)
- Lipoma of the corpus callosum
- Intracranial neoplasms( appear before 2 years=congenital)
- Astrocytoma
- Ependymoma
- Medulloblastoma
- Choroid plexus papilloma
- Medulloepithelioma
- Brain stem glioma
Congenital teratomas
most common brain tumor present at birth. rarely malignant.
almost always SUPRAtentorial, may be intracranial, cervical or in oral cavity/pharynx
Children usually have cleft lip or palate.
sonographically: complex appearance. they may be predominantl cystic, have calcs, or simulate an encephalocele.
Lipoma of the
Corpus Callosum
Mal-development of the neural crest tissues.
associated with dysgenesis of the corpus callosum.
They do not require removal, no mass effect.
sonographically: highly echognic fat, with calcifications present, seen around corpus callosum.
Intracranial neoplasms
brain tumors appearing before the age of 2 years considered congenital. Initial signs may be enlarging head circumference.
Sonographically: brain neoplasms are nonspecific but generally very echogenic and could be mistaken for hemorrhage.
MRI/CT imaging modalities of choice.
Astrocytoma
primary central nervous system tumor that arises primarily in CNS parenchyma contained within the cranial vault (rarely spreads).
low and high grade malignant potential.
2nd most common brain neoplasm in children; 1st teraroma
Ependymoma
glioma made of ependymal cells with low-grade malignant potential.
Medulloblastoma
malignant tumor arising in the cerebellum. common in children
Choroid plexus papilloma:
rare, slow growing (histologically benign) commonly located in the choroid plexus. They cause over-production of CSF and may grow large enough to obstruct CSF flow, causing increased intracranial pressure.
Medulloepithelioma
rare tumor, usually in the brain or retina
Brain stem glioma
largest group of primary tumors of the brain composed of malignant glial cells.
Developmental delays
Any damage to the brain will cause developmental delays including cerebralpalsy and mental retardation. Infants born prematurely are highly susceptible to intracranial hemorrhages with can cause damage to the infants fragile brain.
Infections, birth trauma, genetic defects, fetal alcohol syndrome and sever malnutrition may also cause damage to the brain
Anatropia
vision disorder that is characterized by the visual axis of one eye deviating upward when the other eye is fixed. It is caused by damage to the optic nerve or muscles of the eye. Periventricular leukomalacia, a glioma, or any type of central nervous system disease can affect the optic nerve.
Aniridia
complete or partial absence of the iris.
reduced visual acuity, photophobia (increased sensitivity to light) glaucoma, cataracts, nystagmus (involuntary eye movements) and are increased risk of vision loss. Many have developmental delays.
*associated with Wagner's syndrome (WAGR) W- wilms tumor A- aniridia G- gu anomalies R- mental retardation
Holoprosencephaly
failure of diverticulation when the prosencephalon does not divide into the telecephalon and diencephalon at 4-8 weeks gestation. Septum pellucidum absent in all forms.
characterized: single u-shaped large midline vent, overlying fused or partially fused thalamic structures, presence of thin cortical mantle echoes.
other abnormalities: encephalocele, cystic hygroma, limb defects. death usually occurs within the first year.
Holoprosencephally types:
ALOBAR: most severe, minimal cerebral tissue, large U-shaped ventricle, no separation into hemispheres.
SEMI-LOBAR: more cerebral tissue, facial abnormalities, no specific syndrome.
LOBAR: least severe, partial separation of dorsal aspects of brain, deficiency of cerebral tissue, no facial abnormalities, slightly dilated vents.
Alobar holoprosencephaly
infants are stillborn or die within first few months of life. infants may have cebocephaly or ethmocephaly
the diencephalon fails to separate into 2 thalmi and the telecephalon remains a single cerebral hemisphere with one central ventricle. the cerebellum and brain stem may be normal.
sonographically: large single cavity and minimal amount of cerebral tissue surrounding a single midline vent is seen with fused thalami and choroid plexus and absence of the falx, corpus callosum, and inter-hemispheric
Semilobar holoprosencephaly
has more cerebral and occipital lobe tissue present than Alobar holoprose.
Many associated facial abnormalities with this defect such as a cleft palate and lip, but no specific syndrome.
Lobar holoprosencephaly
deficiency of cerebral tissue; slightly dilated lateral vents, with a flattened roof and squared, fused frontal horns and absent septum peullucidum (all 3 types)
No associated facial abnormalities.
near complete separation of cerebral hemispheres; the Falx and interhemispheric fissure are present.
Holoprosencephaly risk factors:
maternal diabetes, toxoplasmosis, trisomies 13-15-18, intrauterine rubella, and meckel’s syndrome.
Holoprosencephaly sono appearance:
characterized by a single, u-shaped, large midline ventricle, overlying fused or partially fused thalamic structures with presence of thin cortical mantle echoes.
with all 3 types, large cystic space with peripheral brain mantle is seen along with an absent corpus callosum, and fused thalami. absent septum pellucidum.
this allows for differentiation from a large subarachnoid cyst or posterior fossa cyst.
Septo-Optic Dysplasia (De Morsier syndrome)
rare congenital disorder characterized by abnormal development of the optic nerve, pituitary deficiencies and often agenesis of the corpus callosum, schizencephaly and lobar holoprosencephaly.
associated abnormalities of Septo-Optic Dysplasia may cause:
blindness in one or both eyes pupil dilatation in response to light nystagmus (rapid, involuntary, to-and-fro eye movement) inward or outward deviation of eyes hypotonia (low muscle tone) hormonal problems
Infants also suffer from seizures, jaundice at birth and developmental delays due to impaired vision or neurological problems.
Neural tube closure disorders (3)
Arnold-Chiari Malformations I, II, III
Dandy-Walker Complex
Agenesis of the Corpus Callosum
Arnold-Chiari Malformation (3 types)
major anomalies involving the posterior fossa. It is associated with spina bifida and a myelomenigocele. In these types of anomalies, the spinal cord should be investigated for intraspinal masses and to make sure the cord does not extend too low.
- Most common Chiari II
Arnold-Chiari II
most common.
almost always associated with a mylomeningocele, small posterior fossa, an inferiorly displaced cerebellum, pons, and medulla, an obliterated cisterna magna, an elongated 4th ventricle and dilated 3rd and lateral ventricles due to stenosis of the aqueduct of sylvius. An enlarged massa intermedia and partial or total absence of the corpus callosum is seen.
Arnold-Chiari II sono appearance:
“batwing” of the frontal horns, enlarged ventricles, with the occipital horns larger than the frontal horns, and an enlarged massa intermedia filling the third ventricle. the fourth ventricle is not seen due to compression into the spinal canal and partial or complete absence of the septum pellucidum is seen along with elongation of the pons, medulla, cerebellar vermis and cerebellar tonsils.
Arnold-Chiari I
displacement of cerebellar tonsils is seen, no myelomeningocele is evident, 4th vent and medulla normal - incidental finding, usually found on CT
cerebellar tonsils are known as the amygdaline nucleus. The rounded inferior portion of the cerebellar hemispheres.
some patients also have syringomelia- excessive cerebrospinal fluid within the spinal cord
(syrinx- tubular filled cavity in the spinal cord containing CSF)
Syringomelia
excessive cerebrospinal fluid within the spinal cord
syrinx- tubular filled cavity in the spinal cord containing CSF
Arnold-Chiari III
herniation of the cerebellum, medulla, and 4th ventricle into a high cervical encephalocele is seen.
A myelomeningocele and hydrocephalus is always present.
Dandy-Walker complex characterized by:
congenital anomaly of the roof of 4th vent. incomplete formation of the cerebellar vermis, dilatation of the 4th vent which is in direct communication with the cisterna magna and enlarged posterior fossa cyst. (cyst in the cerebellum that involves the 4th vent)
-NOT a posterior fossa arachnoid cyst or mega cisterna magna
hydrocephalus results from the inability of CSF to be drained, due to interference from the presence of the “cyst” (cystic structure where 4th communicates with cistern magna)
difference between Arachnoid cysts and dandy-walker complex
arachnoid cysts do not communicate with the 4th ventricle, but may displace or compress the 4th vent, cerebellum and brain stem
Mega Cisterna magna
normal variant with no mass effect
classic Dandy-Walker
large fluid-filled posterior fossa, cystic-like structure, the dilated 4th vent is seen. the 3rd vent and lateral vents may be dilated due to atresia of the foamina of lushka and magendie.
associated with Meckel-gruber syndrome, VSD malformations and facial clefts.
*small or absent cerebellar vermis, small cerebellar hemispheres, and superior elevation of the tentorium.
hydrocephalus is always present.
Mega cisterna magna
mimics dandy-walker complex.
isolated enlarged cisterna magna
cerebellar vermis, cerebellum and 4th vent normal
Dandy-walker variant
mild hypoplasia of cerebellar vermis and less severe dilation of the 4th vent.
occurs 2x more than classic dandy-walker
Dandy-walker variant sono
prominent cystic area is seen posteriorly and hydrocephalus may or may not be present at the time of initial scan.
Corpus Callosum
forms bands of connecting fibers (probst bundles) between the cerebral hemispheres and the roof of the lateral ventricles.
Agenesis of the corpus callosum
*occurs when the bundles of callosal fibers (probst bundles) parallel each other and do not connect across midline.
associated with a high-riding third vent and may be associated with a dorsal midline cyst
Agenesis of the corpus callosum sono:
marked separation of the lateral ventricles with narrow frontal horns running parallel to each other.
*3rd vent is seen between the anterior horns rather than inferior to them.
sulci and gyri are seen running perpendicular to the 3rd vent
septum pellucidum, cingulate gyrus and cingulate sulcus are also absent
** “sunburst” sign
Cranioschisis/ Dysraphic disorders
failure of neural tube to close; a “splitting of the brain”
level of closure determines which anomaly is present.
Anencephaly, encephalocele, myelomeningocele
Encephalocele
herniation of the meniges or a portion of the brain through a hole in the midline of the skull. the hole may be in the occipital, nasal, or frontal regions.
mass is mostly fluid filled and may contain a small amount of brain tissue. usually located midline.
Encephalocele sono:
cystic or solid, extracranial mass with brain tissue is present wit ventriculomegally. A midline bony defect in the skull will be seen.
Anencephaly
absence of the cranial vault and cerebral hemispheres
Anencephaly sono
facial structures and orbits are present along with absence of the cranium. A mass of disorganized neural tissue is seen above the orbits.
Disorders of proliferation
microcephaly
macrocephaly
MIcrocephaly
small head, more than 3 standard deviations below mean.
Microcephaly may be due to:
Infections: TORCH, HIV, ZIKA
Toxins: radiation, smoking, arsenic, mercury and alcohol
Pre- and perinatal trauma or hypoxic ischemia
Downs syndrome
Malnutrition during fetal life
Microcephaly can lead to:
epilepsy, cerebral palsy, learning disabilities, and hearing or vision loss.
Macrocephaly
head circumference greater than 98th percentile for age
Macrocephaly caused by:
enlarged ventricles, enlarged brain, or a mass-occupying lesion.
Disorders of sulcation and migration
a destructive process occurring in utero causes a disorder of sulcation and cellular migration. may be due to intrauterine infections or error of neuronal migration during organogenesis.
schizencephaly lissencephaly pachygyria heterotopia polymicrogyria
Schizencephaly occurs:
when an in utero insult occurs around 6 weeks to 6 months getation. may be genetic or due to an in utero CMV infection
Schizencephaly
unilateral or bilateral, rough, gray matter, symmetric clefts extend througout the entire cerebral hemisphere.
extend from lateral vent to subarachnoid space and usually are separate from the sylvian fissure, but occur in the area of the sylvian fissure.
cavum septum pellucidum and corpus callosum are often absent.
Schizencephaly sono:
ventricles are squared at the frontal horns due to associated partial absence of the cavum spetum pellucidum and ventricular dilatation is seen iwth gray-matter lined “clefts” extending out to the entire cerebral hemisphere
Lissencephaly
caused by a failure of neuronal migration at no later that the 4th fetal month. the result is a four-layer cerebral cortex. “smooth brain”
*normal cortex is 6 layers
sulci and gyri usually develop with the last 2 layers of cortex and thus non or very few sulci form in lissencephaly.
Lissencephaly sono
agenesis of corpus callosum is seen along with abnormally large ventricles (colpocephaly), dilated 3rd vent and very large sylvian fissure and lack of sulcations in the brain.
Type 2 Lissencephaly
pia is interrupted which allows neurological tissue to spread into and obliterate the subarachnoid space.
*this results in irregular grooves on the brain’s surface, and a “cobblestone” appearing cortex.
no cortical layers present and the lateral ventricles are enlarged.
Pachygyria
mild variant of Lissencephaly.
abnormal cytoarchitecture is present which results in broad gyri and thick cortex.
seen in infants with metabolic CNS disorders
Heterotopia
presence of tissue in an abnormal location. displacement of gray matter into the cerebral white matter or ventricles.
gray matter appears as nodules bulging into the ventricles. many have seizure disorder.
Heterotopia sono
gray matter nodules are seen in the periventriuclar region, oftentimes extending into the lateral ventricles.
Polymicrogyria
abnormal thickening of the cortex due to piling up of many small gyri with a fused surface. occurs near an area of intrauterine insult (toxoplasmosis or CMV)
4 layered cortex in affected region, indicates insult occured no later than the 6th month of gestation
*wavy appearance of ACA and MCA due to poor fomation of the sulci is seen.
Polymicrogyria sono
irregular brain surface is seen with a thickened cortex due to the many small gyri
Subdural and Primary sucharachnoid hemorrhatges
term infants following birth trauma. post-traumatic subdural hematomas best seen on CT
subdural hemorrhages
almost always due to fractured or separated skull
subdural hematomas
uncommon in newborns. subdural hematomas of spin (not common) following repeated attempts of lumbar punctures.
Epidural hemorrhages
occur between skull and dura mater and are due to trauma; best seen on CT
Epidural hematomas
lead to accumulation of arterial blood between the dura and skull
Subperiosteal hematoma (cephalohematoma)
complication of childbirth. Hematoma forms under the scalp in babies delivered with forceps or vacuum delivery. can be a sign of skull fracture
Posterior-fossa sub-dural hematomas
“shaken baby”
due to child abuse/trauma and are often fatal.
Herniation of the brain
can be congenital (chiari) or due to trauma(high increase in intracranial pressure). It is the displacement of brain tissue, spinal fluid and blood vessels outside of the areas they normally occupy.
this condition is often fatal.
most common types: subflacine, trastentorial, tonsillar
Subfalcine herniation
when the cingulate gyrus is pushed laterally due to mass effect beneath the falx cerebri
Transtentorial herniation
occurs either downward or centrally.
In cerebral edema, downward transtentorial herniation can occur when the medial temporal lobe is displaced downward into the posterior fossa.
Central herniation occurs when downward pressure is central and results in bilateral medial temporal lobe herniation.
Tonsillar herniation
when there is edema or hemorrhage in the cerebellum. causes the tonsils of the cerebellum to herniate through the foramen magnum. (or chiari tonsilar herniation)
Indications for spinal ultrasound
less than 6 months of age.
Skin dimples at base of spine, hemangiomas, sinus tracts, hyperpigmented plaques, hairy patches, bony defects seen on xray, VATER syndrome, lower-extremity weakness/paralysis
VATER sydrome
Vertebral anomalies
Anal atresia
TEF (tracheoespophageal fistula)
Renal and radial anomalies
Types of spinal masses that affect spinal cord or canal
Intramedullary
Extramedullary
Intradural, extradural
Intramedullary spinal masses
intrinsic to the cord.
they are within the cord parenchyma. infiltrate and destroy the cord parenchyma.
Types of intramedullary spinal masses primary neoplasms:
Ependymomas Astrocytomas Gliomas Paragangliomas Hemagioblastomas
Extramedullary spinal masses
are in the subarachnoid space outside the spinal parenchyma. they may be intradura, or extradural.
Extramedullary intradural spinal masses
benign and include meningiomas and neurofibromas
Extramedullary extradural spinal masses
mostly metastatic.
Occur from lung, breasst, prostate, renal, thyroid, or lymphatic cancers.
Extradural masses invade and destroy the bony vertebrae before compressing the cord.
Sono appearance of tethered cord
low-lying or blunt ending conus medullaris.
cord motion with breathing or crying is absent, another sign of tethering
The normal conus medullaris lies at the the
L1-L2 disc space. if it extends below this region, a thered cord is present.
In preemies the conus extends below L2-L3 disc space this is tethered.
At 40 weeks the spine should be in the normal position
Syringomelia
cyst in the spinal cord. (AKA syringohydromelia or hydromelia)
elongates and expands over time resulting in destruction of the cord. Damage caused by the cyst causes pain, weakness and stiffness in the back, shoulders or extremities.
Syringomelia is associated with:
myelomenigocele (CSF and nerve mass) and diastematomyelia (split cord)
usually related to Chiari I malformations- syrinx occurs in the cervical region.
Syrinx in the cauda equina or filum terminale
related to tethered cord. a syrinx may also occur as a complication of trauma, menigitis, hemorrhage, tumor or arachnoiditis - the syrinx will be in the area of spinal cord that was affected.
Syrinx sono
appears as a sonlucent area within the cord.
separation of the echogenic linear structures of the central canal will be seen.
Myelomenigocele
cystic mass protruding fro the spinal canal containing CSF and neural elements.
almost always associated with Chiari II malformation.
Meningocele
pouch or sac contains only CSF, not nerves
Myelomenigocele sono
open vertebral ring is seen with a cystic structure present.
Dermal Sinus tracts
Skin tracts lined by epithelial tissue and may be found in or near the midline in the area of the sacrum or lumbar region. 25% regress into a deep dimple on f/u
may appear as a sacral dimple with an opening of 1-2 mm.
*prime source for infection
if tract extends into the thecal sac and form a cyst, tethering may occur.
dermal sinus tracts sono
sonolucent “tract” will be seen between the subcutaneous fat, muscles and vertebral canal.
Diastematomyelia
Split cord malformation. both halve function normally.
bone, cartilage, or fibrous tissue is seen between the 2 halves. the presence of this tissue causes tethering of the cord. surgical intervention is needed to remove the tissue to release the tethering.
Diastematomyelia associated with
“split cord” meningoceles or myelomeningoceles.
skin abnormalities are present such as midline dimples, sinuses, birthmarks, fatty lumps, or small tufts of hair.
Diastematomyelia sono
“split cord” vertebral column has a disorganized appearance.
The vertebral canal appears enlarged and a septum is present where the 2 hemicords are apparent. The split segments are best seen on trv view.
Spinal lipomas
fatty masses in the spinal canal. no usually associated with spina bifida. may be intradural, extradural or both.
lipomas can cause tethering and usually cause gradual compression the the spinal cord causing numbness and tingling of the extremities.
Spinal lipoma sono
highly echogenic mass will be seen in the spinal canal attached to the cord.
Fatty filum
normal variant <2mm
If measures more than 2mm and a mass-like effect of the fat is seen then filar lipoma
Filar lipoma may be associated with myelomenigocele and tethered cord.
Filar cyst
simple cyst in the filum and has no significance. ususally resolve
Lipomyelomeningoceles
congenital lesions of the spine, which form due to failure of the closure of the spinal bones and associated with spina bifida.
Lipomyelomeningocele sono
highly echogenic mas will be seen extending into the spinal canal and nerve roots, the spinal cord and spinal fluid may be seen within the echogenic mass.
treatment includes surgery for removal of the fatty soft tissue mass.
Ventriculus Terminalis (5th ventricle)
ependymal-lined, anatomic remnant at the tip of the conus medullaris which extends to the origin of the filum terminale. It regresses in size during the first few weeks after birth.
8-10 mm length and no more than 2-4 mm diameter
Off the edge of conus
Caudal regression
congenital anomaly of the lower spinal tract. Sacral agenesis is the mildest form and sirenomelia is the most severe.
caudal mesoderm, forms the conus medullaris, filum terminale and sacral nerve roots at 4 weeks gestation, is interrupted at the 3rd week of gestation causing various anomalies of caudal regression.
Caudal regression occurs most often in:
diabetic mothers, and is not inherited
Caudal regression sono:
the conus medullaris is blunted instead of tapereed and is at a lower position that normal, resulting in a tethered cord.
Iniencephaly
rare neural tube defect, involving occipital bone and cervical-thoracic vertebrae. associated with anecephaly and encephaloceles and polyhydramnios.
* fixed fetal head retroflexion
