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Signs and Symptoms
The most common presentation of cerebrovascular diseases is an acute stroke, which occurs when blood supply to the brain is compromised. This includes either an ischemic stroke, where areas of the brain are not well-perfused due to an obstruction or decreased blood flow, or a hemorrhagic stroke, where there is bleeding into or around the brain due to damaged blood vessels. Cerebrovascular diseases such as arteriovenous malformations and aneurysms increase the risk of hemorrhagic stroke. Symptoms of stroke are usually rapid in onset, and may include weakness of one side of the face or body, numbness on one side of the face or body, inability to produce or understand speech, vision changes, and balance difficulties. Hemorrhagic strokes can present with a very severe, sudden headache associated with vomiting and decreased consciousness. Symptoms vary depending on the location and the size of the area of involvement of the stroke. Edema, or swelling, of the brain may occur which increases intracranial pressure and may result in brain herniation. A stroke may result in coma or death if it involves key areas of the brain.

Other symptoms of cerebrovascular disease include migraines, seizures, epilepsy, or cognitive decline. However, cerebrovascular disease may go undetected for years until an acute event, such as a stroke, occurs. In addition, patients with some rare congenital cerebrovascular diseases may begin to have these symptoms in childhood.

Congenital
Congenital diseases are medical conditions that are present at birth that may be associated with inherited through genes. Examples of congenital cerebrovascular diseases include arteriovenous malformations, germinal matrix hemorrhage, and CADASIL (cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy). Arteriovenous malformations are abnormal tangles of blood vessels. Usually, a capillary bed separates arteries from veins, which protects the veins from the higher blood pressures that occur in arteries. In arteriovenous malformations, arteries are directly connected to veins, which increases the risk of venous rupture and hemorrhage. Arteriovenous malformations in the brain have a 2-4% chance of rupture each year. However, many arteriovenous malformations go unnoticed and are asymptomatic throughout a person's lifetime.

A germinal matrix hemorrhage is bleeding into the brain of premature infants caused by the rupture of fragile blood vessels within the germinal matrix of premature babies. The germinal matrix is a highly vascularized area within an unborn infant's brain from which brain cells, including neurons and glial cells, originate. Infants are at most risk to germinal matrix hemorrhages when they are born prematurely, before 32 weeks. The stresses exposed after birth, along with the fragile blood vessels, increase the risk for hemorrhage. Signs and symptoms include flaccid weakness, seizures, abnormal posturing, or irregular respiration.

CADASIL is an inherited disorder caused by mutations in the Notch 3 gene located on chromosome 19. The Notch 3 gene codes for a transmembrane protein whose function is not well-known. However, the mutation causes accumulation of this protein within small to medium-sized blood vessels. This disease often presents in early adulthood with migraines, stroke, mood disturbances, and cognitive deterioration. MRI shows white matter changes in the brain and also signs of repeated strokes. The diagnosis can be confirmed by gene testing.

Acquired
Acquired cerebrovascular diseases are those that are obtained throughout a person's life that may be preventable by controlling risk factors. The incidence of cerebrovascular disease increases as an individual ages. Causes of acquired cerebrovascular disease include atherosclerosis, embolism, aneurysms, and arterial dissections. Atherosclerosis leads to narrowing of blood vessels and less perfusion to the brain, and it also increases the risk of thrombosis, or a blockage of an artery, within the brain. Major modifiable risk factors for atherosclerosis include: • Hypertension

• Smoking

• Obesity

• Diabetes.

Controlling these risk factors can reduce the incidence of atherosclerosis and stroke. Atrial fibrillation is also a major risk factor for strokes. Atrial fibrillation causes blood clots to form within the heart, which may travel to the arteries within the brain and cause an embolism. The embolism prevents blood flow to the brain, which leads to a stroke.

An aneurysm is an abnormal bulging of small sections of arteries, which increases the risk of artery rupture. Intracranial aneurysms are a leading cause of subarachnoid hemorrhage, or bleeding around the brain within the subarachnoid space. There are various hereditary disorders associated with intracranial aneurysms, such as Ehlers-Danlos syndrome, autosomal dominant polycystic kidney disease, and familial hyperaldosteronism type I.  However, individuals without these disorders may also obtain aneurysms. The American Heart Association and American Stroke Association recommend controlling modifiable risk factors including smoking and hypertension.

Arterial dissections are tears of the internal lining of arteries, often associated with trauma. Dissections within the carotid arteries or vertebral arteries may compromise blood flow to the brain due to thrombosis, and dissections increase the risk of vessel rupture.

Idiopathic
Idiopathic diseases are those that occur spontaneously without a known cause. For cerebrovascular diseases, this includes Moya Moya.