Aneurysmal subarachnoid hemorrhage accounts for a small percentage of strokes, but it is a significant contributor to the morbidity rate. The diagnosis is challenging and has devastating consequences if it is missed. Accurate initial diagnosis and management are critical to the outcome of the disease. The emergency clinician must have a high index of suspicion and a judicious approach to evaluating the chief complaint of patients with spontaneous subarachnoid hemorrhage (ie, headache). This review evaluates the literature and current evidence, including controversies and recent American Heart Association guidelines, to support a best-practice approach to the diagnosis and treatment of patients with spontaneous subarachnoid hemorrhage.
You walk into a crowded evening shift in the ED, and your first patient is a middle-aged woman clutching her head in her hands, complaining of the "worst headache of her life." You are worried about a subarachnoid hemorrhage. After treating her pain, you order a noncontrast head CT, which is negative. She now says that her headache is better and that she needs to go home to pick up her kids. Does she really need a lumbar puncture? She eventually agrees to stay for a lumbar puncture, which is also negative. Can she go home now? Does she need any additional workup?
While you are thinking about this, another patient with a history of migraine arrives complaining of suddenonset, severe headache that has lasted 12 hours. Is this headache her usual migraine or could this be a spontaneous subarachnoid hemorrhage? After further history is obtained, you are concerned about a subarachnoid hemorrhage and you obtain a CT, which is normal. You perform a lumbar puncture, which shows some clearing of red blood cells from tube 1 to tube 4. You think it may have been a traumatic tap, but how can you be sure? Just as you are pondering this, the lab calls to say there is xanthochromia. You make the diagnosis of spontaneous subarachnoid hemorrhage. After calling for neurosurgical consultation, what else should you do in the ED to treat this patient?
Subarachnoid hemorrhage (SAH) is the extravasation of blood into the cerebrospinal fluid (CSF). It is usually a diffuse process that results from rupture of corticomeningeal vessels and from hemorrhagic contusions of the brain.1 Trauma is the most common cause of all SAH; however, the majority (85%) of nontraumatic, or spontaneous SAH (sSAH), the focus of this article, are related to aneurysm rupture.2-4 Aneurysmal SAH (aSAH) and other forms of sSAH can pose diagnostic challenges in the emergency department (ED).
Distinguishing traumatic SAH from sSAH may be difficult in some cases because the trauma may have been unwitnessed; however, this distinction is important. See Figure 1 for the typical appearance of a sSAH on noncontrast head computed tomography (CT). The emergency clinician must be able to quickly and accurately identify and categorize SAH, and should be aware of the secondary complications that affect both the central nervous system and other major organs. Initial management and treatment decisions should be made to minimize effects of the initial neurologic injury. This issue of Emergency Medicine Practice focuses on the diagnostic challenges, the initial management and treatment options, and some of the more severe complications of sSAH, using the best available evidence from the literature.
The overall incidence of sSAH is relatively low and, therefore, the availability of high-quality evidence is limited. A literature search was performed using Ovid MEDLINE® and PubMed from 1950 to May 2014. Search terms included subarachnoid hemorrhage, aneurysm, thunderclap headache, sentinel headache, lumbar puncture, xanthochromia, emergency department, head CT, CTA, angiography, MRI, nimodipine, risk factors, prehospital care, diagnosis, management, analgesia, treatment, rebleeding, vasospasm, hypertension, antiepileptic, and combinations of these keywords. The search was limited to the English language and human studies. More than 500 articles were reviewed, which provided background for further literature review. During the literature review process, the highest value was placed on clinical trials, larger prospective cohort studies, and meta-analyses of clinical trials. Secondary evidence was collected from retrospective studies, case-control studies, and other metaanalyses. Finally, expert consensus statements and case reports were reviewed. The Cochrane Database of Systematic Reviews and the National Guideline Clearinghouse (www.guideline.gov) were also consulted.
The most relevant guidelines for emergency clinicians are the 2008 American College of Emergency Physicians (ACEP) Clinical Policy on acute headache (see Table 1),5 the 2012 American Heart Association (AHA) Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage,6 (see Table 2) and the 2011 Neurocritical Care Society (NCS) Guidelines on the critical care management of patients with aSAH.7
Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.
To help the reader judge the strength of each reference, pertinent information about the study will be included in bold type following the reference, where available. In addition, the most informative references cited in this paper, as determined by the authors, will be noted by an asterisk (*) next to the number of the reference.
Imoigele Aisiku, MD, MBA; Jonathan A. Edlow, MD, FACEP; Joshua Goldstein, MD; Lisa E. Thomas, MD
October 1, 2014