neurologic disorders
Transient Ischemic Attack (TIA)
Etiology of TIA
Risk factors for TIA are the same as those for ischemic stroke. Modifiable risk factors include the following: Hypertension None Cigarette smoking Dyslipidemia None Diabetes Mellitus (DM) None Insulinresistance Obesity None Obstructive Sleep Apnea (OSA) None Excess alcohol consumption Lack of physical activity High-risk diet (eg, high in saturated fats, trans fats, and calories) Psychosocial stress (eg, Depressive Disorders ) Heart disorders (particularly disorders that predispose to emboli, such as Acute Myocardial Infarction (MI) , Carotid artery stenosis Use of certain drugs (eg,cocaine, amphetamines) Overview of Thrombotic Disorders None Overview of Vasculitis None Exogenous estrogen Unmodifiable risk factors include the following: Prior stroke Older age Family history of stroke Male sex Most TIAs are caused by emboli, usually from carotid or vertebral arteries, although most of the Etiology can also result in TIAs. Uncommonly, TIAs result from impaired perfusion due to severe hypoxemia, reduced oxygen-carrying capacity of blood (eg, profound Etiology of Anemia , Insubclavian steal syndrome,a subclavian artery stenosed proximal to the origin of the vertebral artery “steals” blood from the vertebral artery (in which blood flow reverses) to supply the arm during exertion, causing signs of vertebrobasilar ischemia. Occasionally, TIAs occur in children with a severe cardiovascular disorder that produces emboli or with a very high hematocrit due to chronic hypoxemia. 