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"