<prompt> Answer this question truthfullyWhat is the cause of aortic aneurysm in the thoracic region?  <response>: <reason> Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.Aortic dissectionAortic dissection Atherosclerosis Marfans syndromeAnkylosing spondylitis Aortic dissection Aortic stenosis Aortitis Aortic valve replacement Arterial tortuosity syndrome Atherosclerosis Bacterial infection, often following valvular endocarditisSalmonella Staphylococcus aureus Staphylococcus epidermidis Streptococcus TuberculosisBehcets disease Bicuspid aortic valve Ehlers-Danlos syndrome Familial thoracic aortic aneurysms and dissections Giant cell arteritis Loeys-Dietz syndrome Marfans syndrome Quaternary syphilis Reactive arthritis Rheumatoid arthritis Rheumatoid vasculitis Septic embolism Systemic hypertension Takayasus arteritis Temporal arteritis Traumatic - Sudden deceleration Turners syndrome Wegeners granulomatosis 