Subarachnoid Hemorrhage: State of the Art(ery)

Headache is a common chief complaint in primary and ambulatory care settings. The etiology of headache is usually benign, its workup is often minimal and straightforward, and the clinical approach focuses primarily on symptom control. A small proportion of headaches is caused by subarachnoid hemorrhage (SAH), most of which are due to ruptured cerebral aneurysms. Such hemorrhage carries a high mortality, with significant rates of devastating disability among survivors. Misdiagnosis of SAH is frequent and results in medicolegal risk to the unwary physician. An organized, algorithmic approach emphasizes high risk historical and physical examination features that suggest SAH. Expeditious neuroimaging and lumbar puncture are employed to confirm suspected SAH. Diagnosis of SAH requires immediate stabilization, followed by neurosurgical consultation for definitive management. Transfer to high-volume neurosurgical and endovascular centers is associated with improved outcomes for SAH. Introduction Headache is a common chief complaint in the emergency department (ED), constituting approximately 2% of all visits. Of these patients, about 1% will have subarachnoid hemorrhage (SAH).1, 2 In the subset of patients who present with a severe, sudden onset, or “thunderclap,” headache and a normal neurologic examination, 10% to 16% will have SAH.3-8 Thus, emergency physicians see only one subarachnoid hemorrhage out of every 100 headache patients. Further, it is estimated that 5-15% of these are initially misdiagnosed.9-13 Delayed diagnosis of SAH confers worse outcomes, highlighting the importance of early recognition and treatment.14 The mortality of SAH is approximately 40%, with another 30% surviving with significant neurological disability.15 Misdiagnosis of SAH is an important cause of medico-legal actions against physicians.5,7,9-13,15-18 At the same time, an extensive workup of every headache patient in the ED is neither practical nor necessary. Because the diagnosis of SAH will not be made if it is not considered, deciding whom to evaluate for SAH and how to conduct this evaluation can be difficult. CT and LP are the mainstays of the emergency evaluation for SAH. Once the decision has been made to perform these tests, interpreting their results may also be challenging.18 This article will review the current literature on the diagnosis and management of SAH. Emphasis will be placed on an algorithmic approach that is aimed at a rapid risk assessment utilizing history and physical examination and on the selective use and correct interpretation of CT and LP (Figure 1). Using this approach, patient outcomes may be optimized, while medicolegal risk may be reduced. Suspected SAH Non Con Head CT Negative