Presentation and Natural History

Intracranial aneurysms (IAs) are prevalent in as many as 3% of the population and can present in living patients asymptomatically after incidental imaging or in a clinical presentation with headache, neurological signs, and symptoms up to and including coma. There are several risk factors underlying the formation, progression, and rupture of intracranial aneurysms. With recent advances in technology, multiple treatment options exist for IAs, with treatment options and timing differing depending on the mode of patient presentation. Careful assessment of the risk of progression and rupture of IAs, weighed against risks of intervention (either surgical clipping or endovascular treatment), should guide management. A thorough understanding of the natural history of IAs is therefore very helpful. This chapter discusses the clinical presentation and natural history of intracranial aneurysms.