Causes of Seizures 1/16 Flashcards
Types of brain herniation
Subfalcine herniation
may compress ant. cerebral art.
transtentorial herniation
may compress:
1) CNIII= see ipsilateral dilated pupil and impaired eye movement
2) post. cerebral art.= primary visual cortex
3) cerebral peduncle=kernohan’s notch, ipsilateral hemiparesis
4) pons and midbrain= duret hemorrhage due to vessel tearing–>life threatening
tonsillar herniation
brain stem compression–>cardiac and respiratory centers
NO LP if CT shows:
mid-line shift, loss of CSF cisterns, post. fossa mass–>high risk of herniation
CT without contrast
hemorrhage/hematoma, skull fx/trauma, hydrocephalus, fluid accumulation/abscess
CT with contrast
tumor(angiogenesis), vascular malformation, infection/inflammation
intracranial hemorrhage
related to HTN and peak age is 60. most frequent sites: thalamus, basal ganglia, pons and cerebellum
Charcot-bouchard micro aneurysms
associated with chronis HTN. Minute aneurysms in small vessels which can rupture
subarachnoid hemorrhage
caused by bleeding from cerebral arterial aneurysms. bleeding is at arterial pressure. “The worst headache of my life” then loss of consciousness. re-bleeding is common among survivors.
Acute: vasospasm–>ischemia
chronic: meningeal fibrosis–>hydrocephalus
berry aneurysm
bright red, shiny surface and a thin, translucent wall. often arise at junctions of vessels due to defect in vessel walls at branch points.
cerebral vessels have only one elastic lamina(internal elastic lamina)–>more prone to dilation
picture of berry aneurysm development
atherosclerotic aneurysm
arises as dilation of entire part of an artery weakend by atherosclerosis. less common than berry.
mycotic aneurysm
arises in vessel walls weakend by microbial infx, usually bacteria, despite the name.
epidural hematoma
due to rupture of middle meningeal art. due to traumatic skull fx–>seperation of dura from inner surface of skull–> compression of brain.
pts lucid for several hours then develop neurological signs. emergency drainage required
picture of epi and subdural hematomas
subdural hematoma
bridging veins from cortical convexities to sup. sagittal sinus travel through the space between dura and arachnoid layer (subdural).
elderly with cerebral atrophy are at risk due to stretching of veins. Infants are also at rick because veins are thin-walled and fragile
signs and symptoms of chronic subdural hematoma
headache, confusion and focal signs
CSF production
by choroid plexus in lateral and 4th ventricles–>enters subarachnoid space at cisterna magna through foramina of luschka and magendie.
CSF reabsorbed through arachnoid granulations of sup. sagittal sinus.
hydrocephalus
obstruction, overproduction, loss of cerebral tissue.
if before closure of cranial sutures–>increased head circumference
after–>increased ICP
non-communicating hydrocephalus
obstruction within ventricular system: mass lesions, aqueductal stenosis, obstruction of 4th ventricle
communicating hydrocephalus
obstruction outside the ventricular system: subarachnoid hemorrhage or meningitis with secondary meningeal scarring
hydrocephalus ex vacuo
if there is less brain tissue–>compensatory enlargement of ventricles (alzheimer’s)
choroid plexus papilloma
results in csf overproduction
Preference of location of brain abscesses
frontal lobe>parietal>cerebellum
clinical findings of brain abscess
progressive focal deficits, increased csf, white cells and protein, normal glucose
arterio-venous malformations AVM
largest intracerebral malformations, tangled network of wormlike vascular channels, prominent pulsatile arterio-venous shunt with high blood flow through the malformation.
tend to occur in cerebral hemispheres
cavernous hemangioma
greatly distended, loosly organized vascular channels with thin, collagenized walls
capillary hemangioma
rarely cause symptoms during life
tuberculous meningoencephalitis
csf: moderate lymph or lymph+poly, protein elevated, glucose moderately reduced or normal
arteries in subarachnoid space may show obliterative endarteritis (heubner’s arteritis)
pus usually accumulates at base of brain
Brain tumors in adults
supratentorial. Gliomas are most common primary tumors>meningioma
brain tumors in chidren
secondary to hematopoietic tumors. Infratentorial. most are astrocytoma>medulloblastoma>ependymoma
infratentorial tumors
adults: schwannomas>gliomas of brain stem> mets
children: astrocytoma>medulloblastoma>ependymomas
extradural tumors of spine
usually within vertebral body. most common in adult: mets>primary tumors of bone
intradural tumors of spine
between dura and spinal cord or within spinal cord=intramedullary
meningioma>ependymoma>astrocytoma
astrocytoma high grade=glioblastoma multiforme=anaplastic astrocytoma
increased number of astrocytes that are anaplastic, necrosis with pseudopallisading of tumor cells. poor prognosis–>cerebral edema+herniation
pilocytic astrocytoma
usually in cerebellum, but also optic nerve and 3rd ventricle. usually benign but 3rd ventricle pilocytic astrocytoma has poor prognosis
oligodendroglioma
fried egg appearance, well-circmscribed, can be cystic with calcification
ependymoma
tumor of 4th ventricle–>hydrocephalus, in young children
Can occur in spinal cord in middle life. See ependymoma rosettes
medulloblastoma=pnet=peripheral neuroectodermal tumor
usually found in cerebellar vermis and can spread down the spinal cord=drop mets. See small cells with prominent nucleoli, scant cytoplasm and occasional rosettes
meningioma
benign, from subarachnoid cell, see whorls with psammoma bodies, compresses the brain
primary CNS lymphoma
from microglia, associated with AIDS and renal transplant, mostly B cell phenotype, diffuse infiltration of brain tissue, micro:see large cell lymphoma, poor prognosis
Lesions are often multiple in gray and white matter
mets to brain
often multiple, well-circumscribed and at white-gray junction. Often come from lung, breast, kidney
carcinomatous meningitis
tumor deposits throughout CNS in subarachnoid space–>widespread neurological dysfunction.
Seen most often with adenocarcinomas, including carcinomas from breast or stomach
schwannoma
acoustic neuroma, CNVIII, Antoni A and B, verocay bodies (pallisading of nuclei), thickend vessels
Neurofibroma
NF 1 mutation, fusiform noncircumscribed enlargement of nerve seen often at distal part of nerve. micro: see interlacing bands of spindle cells wih elongated nuclei. Hard to remove from nerve. Can infiltrate adjacent tissue.
