Stroke Flashcards
Define Stroke
Is a sudden loss of blood supply to the brain leading to permanent tissue damage caused by thrombotic, embolitic or heamorrhagic events
What type of herniation if brain compressed under the Falx Cerebri
Subfalcine or Cingulate
What type of herniation if brain compressed under the Tentorium Cerebelli
Transtentorial or Uncal
What type of herniation if brain compressed through the foramen Magnum
Tonsilar
What are the typical symptoms of a Uncal or transtentorial herniation
- CNIII compression resulting in no pupil reflex and no occulomotor function
- Corticospinal tract compression resulting in postural symptoms
- Occipital lobe compression of the primary visual cortex (V1) resulting in homonymous hemianopia
What are the most common causes of Stroke
Infarction due to occlusion (80%), haemorrhage (15%) and sub-arachnoid haemorrhage (5%)
What happens to Neurons after infarction
Loss of oxygen input, cannot produce ATP, loss of ion pumps, cells swell, can have increased ICP and then herniation
What causes majority of deaths?
Secondary effects such as pneumonia, CVD(share commone risk factors) or PE
Primary features of Stroke that lead to death
Death of neurons in control centres or Raised ICP
Causes of Ischemic Stroke
Small vessel disease from Hypertension, thrombosis, emboli from athero-emboli + ulceration, pump failure, DVT (hole in heart to bypass lungs)
Causes of hemorrhagic Stroke
Hyaline Artherosclerosis, Aneurysms (saccular or Berry), Amyloid angiopathy, bleeding disorders, atherosclerosis, tumour, surgery, congenital problems (no capillaries and venous rupture) or drugs
Common Sites of Thrombus generation in the circle of Willis
Vertebral Arteries, Basilar arteries, MCA and internal carotid
Common sites of Aneurysms
ICA junction, MCA bifurcation, Posterior and Anterior Communicating Arteries, most likely will affect the anterior region of circulation
Risk Factors of Stroke
- CVD factors ○ Such as aging, hyperlipideamia - Hypercoagulable states ○ Bleeding or thrombus formation - Cardiac disease (AF) - Diabetes
What are lucunar infarcts
infarcts that occur to deep structures
Consequences of hyaline arteriolosclereosis
Protein deposition in response to hypertension leading to vessel occlusion and infarct. However can also lead to wall weakening and the vessel can form aneurysms and the lead to haemorrhage
Causes of cardiac mediated strokes
Anuerysms of left ventricle, valve vegetation, AF, DVT (septal defects)
Pathogenesis of Strokes
Ischemia, cells die, cells swell, raised ICP, compensation, if prolonged and severe leads to hearniation and death. if resolved, the cells can swell, pycnotic nucleus, liquefaction necrosis and macrophage infilatration. Days to weeks for macrophages to remove dead tissue and therefore around 1-2 months will form a cystic cavity filled with CSF like fluid
What is re-perfusion injury
Thrombi/emboli occlude vessel, leads to vascular death, resolution of thrombi and then heamorrhage as the blood vessels not able to withstand pressure.
What is a duret’s haemorrhage
Is bleeding in the brainstem due to raised ICP
Where are Congophillic/Amyloid angiopathy commonly localised
Small/recurrent peripheral hemorrhages of the cerebrum and is associated with Alzheimer’s disease
Risks of Cerebellar haemorrhage
May not lead to cerebellum defects yet has the potenital to block the 4th ventricle and hence pressure must be releived
What are the most likely vessels that result in intracerebral heamorrhages
Deep vessels due to hyaline arteriolosclerosis, can be the lenticulostriate vessels to the basal ganglia
What is the most likely cause of mutlifocal haemorrhages
Coaggulopathy problems from clotting factor disorders, thrombocytopenia or leukemia
Causes of Sub-arachnoid haemorrhages
Ruptures of Succulent Aneurysms (Berry are congenital)
Risk Factors of Saccular Aneuryms
Sex and Age (Female and young), Polycystic kidney disease, collagen disorders, hypertension, congenital coartation of aorta, smoking and alcohol
Most common regions
Anterior blood supply (90%) and posterior blood supply (10%) at the MCA bifurcation, ICA trifurcation and the communicating arteries. There are risks too of ventricular haemorrhage
treatment of Aneurysms and why?
Clip the neck of aneurysms, remove blood to prevent raised ICP,cerebral odema, hydrocephalus and vasospasm
