According to it's pathology, stroke can be classified into hemorrhagic and ischemic. Ischemic stroke happens when blood supply to the brain is insufficient while hemorrhagic stroke happens when cerebral vessels rupture which also causes insufficient blood supply. None of them has any difference in presentation but is important in management. For your first question, stroke is not common at a young age because the common cause of stroke are artherosclerosis and embolism ( the obstruction of an artery by an embolus, which is usually a piece of clotted blood which breaks away from one part of the circulatory system and travels to another but can also be gas or fat ) which is common in elderly . The cause must be taken seriously in a younger person. Presymptoms of stroke is tia .Tia ( transient ishemis stroke) it has a similar presentation as stroke. Tia is defined as the sudden onset of focal cns sign and symptom < 24 hours from a reduction in blood flow. Typically the neurologic signs and symptoms of tia last for 5 to 15 min but according to definition, it is <24 h. Common symptoms of stroke include abrupt onset of hemiparesis, monoparesis, or quadriparesis; monocular or binocular visual loss; visual field deficits; diplopia; dysarthria; ataxia; vertigo; aphasia; or sudden decrease in the level of consciousness . Although such symptoms can occur alone, they are more likely to occur in combination. Unless there are better advisor, I cannot answer the prestroke question fully. This is because stroke most commonly present acutely or sudden but in ischemic stroke particularly in the elderly, it may presents gradually from a decline in intellectual function ( dementia ) with or without sensory limb deficits. Hemorrhagic stroke is also sudden with neck stiffness, headache and vomitting with or without brain damage.
What are the causes of stroke ?
Ischemic stroke
1) cardiogenic embolism : it is when there is an embolism from the heart the the cerebral arteries. That only happens when there is a valve disease or a thrombus in the heart chamber. Young adults with congenital ( born with it ) heart defect, a history of rheumatic fever or bacterial endocarditis are causes in young adults.
2) small arteries disease : for example artherosclerosis ( narrow or vessels from the formation of a plaque) which is usually in the elderly and hpt.
3) large arterial embolism : this could be artherosclerosis, infective causes ( syphilis, tuberculous ) , collagen vascular disease (takayasu, systemic lupus erythemathous and giant cell arthritis; all are in young female except for giant cell arteritis which is seen in elderlu ).
4) blood disorder : polycythemia rubra vera, antiphospholipid syndrome, sickle cell disease
hemorrhagic stroke
trauma, tumor, bleeding tendency, vascular malformation are some of the causes.
