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.
