Cerebrovascular Disease Flashcards
What deficits are caused by damaging the anterior cerebral artery (ACA)?
Upper motor neuron type weakness and cortical type sensory loss, contralateral hemiplegia initially; contralateral leg more than the face or arms; alien hand syndrome
What is alien hand syndrome?
Semiautomatic movements of the contralateral arm not under voluntary control
What deficits are caused with damage to the PCA?
Contralateral homonymous hemianopia (loss of vision of half of visual field of one or both eyes)
In which artery are infarcts and ischemic events more common?
MCA
What are the deficits caused by damage to the MCA?
Aphasia, hemineglect (lack of awareness to half of the body), face-arm or face-arm-leg sensorimotor loss; gaze preference toward side of the lesion
What is cerebrovascular disease?
Injury to the brain as a consequence of altered blood flow; can be grouped into ischemic and hemorrhagic etiologies with tissue infarction the ultimate consequence
What are the most common cerebrovascular disorders?
Global ischemia (whole brain), embolism, hypertensive intraparenchymal hemorrhage, ruptured aneurysm
When blood flow is reduced, what does survival depend on?
Collateral circulation, duration of ischemia, and magnitude + rapidity of flow reduction
What are the 2 types of reduction in blood flow?
- Global ischemia (generalized reduction of perfusion due to cardiac arrest,shock, severe hypotension);
- Focal ischemia in a localized area (emboliform or thrombotic arterial occlusion, vasculitides, atherosclerosis in HTN
What are watershed infarcts?
Blood supply to two adjacent cerebral arteries compromised —> region between the 2 vessels most susceptible to ischemia and infarction; damage to this region produces a sickle shaped band of necrosis over the cerebral convexity a few cm lateral to the interhemispheric fissure
What are the effects of an ACA-MCA watershed infarct?
Occlusion of the ICA, hypotension in pt with carotid stenosis; proximal arm and leg weakness with transcortical aphasia and language issues
What are the effects of an MCA-PCA watershed infarct?
Higher order visual processing changes
What are the two patterns of border zone infarcts?
Cortical border zone infarctions and internal border zone infarctions
What are cortical border zone infarctions?
Infarctions of the cortex and adjacent subcortical white matter located at the border zone of ACA/MCA and MCA/PCA
What are internal border zone infarctions?
Infarctions of the deep white matter of the centrum semiovale and corona radiata at the border zone between lenticulostriate perforators and the deep penetrating cortical branches of the MCA or at the border zone of deep white matter branches of the MCA and ACA
What are risk factors for hypercoagulability?
Heritable coagulation factor disorders (protein S, C or anti thrombin III deficiencies), dehydration, adenocarcinoma/malignancies, surgery, trauma, childbirth, DIC, hematologic disorders (sickle cell, leukemia, polycythemia Vera) and vasculitis (temporal arteritis, SLE, infections, neoplasms)
What needs to be ruled out in a young child who presents with a stroke?
Sickle cell
What are the RF for a stroke?
HTN, DM, hypercholesterolemia, cigarette smoking, +FHx, cardiac dz (valvular dz, Afib, PFO, low ejection fraction), prior Hx of stroke or other vascular dz, hypercoagulability
If a young pt presents with stroke what should you think of?
Arterial dissection, PFO, or hypercoagulability (also sickle cell)
What are the 4 principle routes of CNS infections?
Hematogenous, direct implantation, local extension, PNS
What is hematogenous spread?
MC route of infection; arterial primary but retrograde venous spread via anastomosis with facial veins possible
What can cause direct implantation of a pathogen?
Trauma or congenital malformation (meningomyelocele)
What can lead to local extension of a pathogen?
From infected adjacent structures such as sinuses, teeth, skull/cranial, vertebra (spinal osteomyelitis)