Cranial Nerve stuff, year 2 repeat Flashcards
Vascular malformations of the brain are classified into four principal groups
- arteriovenous malformations
- cavernous malformations
- capillary telangiectasias
- venous angiomas
Which vascular malformations are associated with hemorrhage?
ateriovenous malformation
cavernous malformation
Arteriovenous malformations (AVM)
- Which vessels?
- How do they appear grossly?
- What do they do?
- how are they composed?
- what do they “often” show evidence of?
- may involve vessels in either subarachnoid space or brain, or both.
- tangled network of wormlike vascular channels
- have prominent, pulsatile arteriovenous shunting with high blood flow.
- composed of greatly enlarged blood vessels separated by gliotic tissue
- often showing evidence of prior hemorrhage
Cavernous malformations
- distended, loosely organized vascular channels
- arranged back to back
- have collagenized walls of variable thickness.
- usually no brain parenchyma between vessels in this type of malformation.
- “low-flow” channels that do not participate in arteriovenous shunting.
Morphology of the AVM
Two patterns:
- arteries with duplication and fragmentation of the internal elastic lamina
- arteries with thickening or partial replacement of the media by hyalinized connective tissue.
Cavernous malformations
- What “frequently” surrounds the vessels?
- where they occut most often in order of decreasing frequency
- Foci of old hemorrhage
- infarction
- calcification
- frequently surround the abnormal vessels
- Occur most often (in decreasing order of frequency)
- cerebellum
- pons
- subcortical regions
Capillary telangiectasias
Capillary telangiectasias
microscopic foci of dilated, thin-walled vascular channels separated by relatively normal brain parenchyma that occur most frequently in the pons.
Venous angiomas (varices)
consist of aggregates of ectatic venous channels.
Foix-Alajouanine disease
- angiodysgenetic necrotizing myelopathy
- venous angiomatous malformation of spinal cord + overlying meninges
- most often in lumbosacral region
- associated with
- ischemic injury to the spinal cord
- slowly progressive neurologic symptoms.
- the most common type of clinically significant vascular malformation
- M vs W
- age when first presents
- how it presents
- Arteriovenous malformations
- Males are affected twice as frequently as females.
- lesion often presents between the ages of 10 and 30 years as a seizure disorder, an intracerebral hemorrhage, or a subarachnoid hemorrhage.
AVMs
- most common site of hemorrhaging
- how it might manifest in a newborn
- most common site: territory of middle cerebral artery
- particularly its posterior branches.
- Large arteriovenous malformations occurring in the newborn period can lead to congestive heart failure because of shunt effects, especially if the malformation involves the vein of Galen.
this class of vascular malformation has common familial form. what are its hallmarks?
Cavernous malformations. Multiplicity of lesions is a hallmark of familial cases, which are inherited as a highly penetrant autosomal dominant trait.
Key Concepts
Stroke
clinical term for acute-onset neurologic deficits resulting from hemorrhagic or obstructive vascular lesions.
Key Concepts
Cerebral infarction
Cerebral infarction follows loss of blood supply and can be widespread or focal, or affect regions with the least robust vascular supply (boundary zones).
Key Concepts
Focal cerebral infarcts
Focal cerebral infarcts are most commonly embolic; with subsequent dissolution of an embolism and reperfusion, a nonhemorrhagic infarct can become hemorrhagic.
