Primary intracerebral hemorrhage and subarachnoid hemorrhage

Abstract

Intracerebral hemorrhage (ICH) constitutes about 13% of stroke cases in the United States. I In Asian populations, the frequency may be as high as 30% of all strokes. 2 The United States age-adjusted incidence of ICH is 10 to 15 per 100,000 per year and doubles with each decade after age 45. 3,4 After a steady decline in incidence from 1945 through 1974, possibly reflecting better management of hypertension, the rate of ICH increased in Rochester, Minnesota, from 1975 through 1979 which was attributed to the introduction of computed tomography (CT). s The case fatality rate of ICH is about 50% and is related to the hemorrhage location and volume, as well as to the clinical grade of the patient. ICH may be classified as primary or secondary. The major risk factors for primary ICH are age, hypertension, alcohol abuse, and very low serum cholesterol. 6; The causes of secondary ICH vary by age. In young adults, drug abuse, vascular malformations, aneurysms, and coagulopathies are the most common causes. In middleaged adults, metastatic and primary brain tumors and anticoagulation therapy are additional important causes. In the elderly population, amyloid angiopathy is probably the single most frequent cause of ICH. s The most frequent sites of primary spontaneous (often called hypertensive) ICH are the putamen (50%), thalamus (15%), pons (10% to 15%), and cerebellum (10%). Lobar or multiple hemorrhages should suggest a cause other than hypertension.