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INTRODUCTION

Although hemorrhagic strokes, including nontraumatic subarachnoid hemorrhages and intracerebral hemorrhages, account for a relatively small portion of ED visits, a missed diagnosis can produce devastating results. Early recognition and aggressive management may improve outcomes. Hemorrhagic stroke accounts for 15% of all strokes and is classified according to the anatomic location of the bleed; nearly one third of hemorrhagic strokes are the subarachnoid type, whereas two thirds are from intracerebral hemorrhage.1

Subarachnoid hemorrhage is the leakage of blood into the subarachnoid space and classically presents as a sudden, severe headache. Intracerebral hemorrhage, bleeding into the brain parenchyma itself, typically presents as an acute neurologic deficit, often accompanied by headache. The features and treatment of subarachnoid and intracerebral hemorrhage are discussed in this chapter. Management of intracerebral hemorrhage is very different from the management of ischemic stroke. Ischemic stroke is discussed in Chapter 167, “Stroke Syndromes.”

SUBARACHNOID HEMORRHAGE

EPIDEMIOLOGY

About 75% of atraumatic subarachnoid hemorrhages are caused by a ruptured aneurysm. In about 20% of cases a cause is not identified.2 The remaining causes are related to a variety of miscellaneous conditions, including arteriovenous malformations, sympathomimetic drugs, and other less common causes. About 20% of patients with one aneurysm will have an additional aneurysm, which makes identification of the initial aneurysm important.

Two percent of family members of patients with subarachnoid hemorrhage will develop the same disease. This risk rises with increasing number of family members involved or with a family history of adult polycystic kidney disease.2 Hypertension and smoking increase risk as well. Additional risk factors are listed in Table 166-1.

TABLE 166-1Risk Factors for Subarachnoid Hemorrhage

PATHOPHYSIOLOGY

Cerebral aneurysms are focal arterial pouches typically located in areas of bifurcation of the circle of Willis. While the precise pathophysiology is not known, many factors have been associated with aneurysmal development and rupture. Such factors include genetic predisposition, cellular aberrations in vascular wall repair or remodeling, and aberrations in local blood flow.3 While it is not possible to predict rupture risk of a particular aneurysm, larger aneurysms (>5 to 10 mm) are more likely to rupture than smaller aneurysms.3,4

CLINICAL FEATURES

Patients with subarachnoid hemorrhage classically present to the ED with a severe headache of acute onset (termed a “thunderclap” headache) that reaches maximal intensity within seconds. Typically, the headache persists for several days but may resolve in a shorter period of time.2 Subarachnoid hemorrhage is diagnosed in 11% to 25% of patients who ...

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