A silent stroke typically affects regions of the brain associated with various thought processes, mood regulation and cognitive functions and is a leading cause of vascular cognitive impairment and may also lead to a loss of urinary bladder control.In the Cardiovascular Health Study, a population study conducted among 3,660 adults over the age of 65. 31% showed evidence of silent stroke in neuroimaging studies utilizing MRI. These individuals were unaware they had suffered a stroke. It is estimated that silent strokes are five times more common than symptomatic stroke.A silent stroke differs from a transient ischemic attack (TIA). In TIA symptoms of stroke are exhibited which may last from a few minutes to 24 hours before resolving. A TIA is a risk factor for having a major stroke and subsequent silent strokes in the future. Types
Ischemic stroke: occurs when a blood vessel supplying blood to the brain becomes blocked. This type of stroke accounts for approximately 87 percent of all stroke cases. Hemorrhagic stroke: occurs when a blood vessel supplying blood to the brain becomes weakened and ruptures. Typically hemorrhagic stroke is caused by two types of weakened blood vessel: aneurysms and arteriovenous malformations (AVMs). Lacunar infarcts (LACI) are small (0.2 to 15 mm in diameter) noncortical (does not affect cerebral cortex) infarcts caused by the occlusion of a single penetrating branch of a larger blood vessel that provides blood to the brains deep structures including the  white matter.
Increased levels of CRP as measured by a CRP test or the more sensitive high serum CRP (hsCRP) test have a close correlation to increased risk of silent stroke. Interleukin-6 is an interleukin (type of protein) produced by T-cells (specialized white blood cells), macrophages and endothelial cells. IL6 is also classified as a cytokine (acts in relaying information between cells). IL6 is involved in the regulation of the acute phase response to injury and infection may act as both an anti-inflammatory agent and a pro-inflammatory. Increased levels of CRP as measured by a CRP test or the more sensitive high serum CRP (hsCRP) test and elevated levels of I6 as measured by an IL6 ELISA are markers for the increased risk of silent stroke. Diabetes mellitus: untreated or improperly managed diabetes mellitus is associated with an increased risk for silent stroke. Hypertension: which affects up to 50 million people in the United States alone is the major treatable risk factor associated with silent strokes. Homocysteine: elevated levels of total homocysteine (tHcy) an amino acid are an independent risk factor for silent stroke, even in healthy middle-aged adults. Metabolic syndrome (MetS):Metabolic syndrome is a name for a group of risk factors that occur together and increase the risk for coronary artery disease, stroke, and type 2 diabetes. A higher number of these MetS risk factors the greater the chance of having a silent stroke.Polycystic ovary syndrome (PCOS): is associated with double the risk for arterial disease including silent stroke independent of the subjects Body mass index (BMI).