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Content Update
September 26, 2016
New evidence against platelet transfusion after spontaneous primary intracerebral hemorrhage in patients who are taking antiplatelet therapy. See Reverse Coagulopathy and reference 46.
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Although nontraumatic subarachnoid 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.
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Subarachnoid hemorrhage is the leakage of blood into the subarachnoid space, most often due to a ruptured intracranial aneurysm. The classic presentation is a sudden, severe headache.
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Intracerebral hemorrhage, or hemorrhagic stroke, 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.
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SUBARACHNOID HEMORRHAGE
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About 75% of subarachnoid hemorrhages are caused by a ruptured aneurysm. In about 20%, a cause is not identified.1 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.
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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.1 Hypertension and smoking increase the risk. Additional risk factors are listed in Table 166–1.
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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 familial/genetic predisposition, cellular aberrations in vascular wall repair or remodeling, and aberrations in local blood flow.2 While it is not possible to predict rupture risk of a particular aneurysm, larger aneurysms (>5–10 mm) are more likely to rupture than smaller aneurysms.2,3
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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 minutes. Typically, the headache persists for several days, but may resolve in a shorter period.1 Subarachnoid hemorrhage is diagnosed in 11% to 25% of patients who present to the ED with a thunderclap headache.4...