Subarachnoid Hemorrhage Revisited

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    Subarachnoid Hemorrhage Revisited

    Does that young, well appearing patient with the “worst headache of their life” really need that lumbar puncture (LP)? It’s an issue that’s constantly weighing over physicians’ heads when evaluating a patient with headache in the emergency department. The thought of potentially missing a sentinel bleed from an aneurysm or AVM is something that keeps us up at night. Few studies have directly asked the question – is it sufficient to perform a CT angiography (CTA) of the head without a lumbar puncture in  the evaluation of subarachnoid hemorrhage?

    In 2010 there was a mathematical analysis performed which showed that CT/CTA is almost as effective as CT/LP in identifying subarachnoid hemorrhage, although no prospective randomized trials have  been performed due to the sheer number of patients required to obtain sufficient power.

    Then in 2011 BMJ released an important article suggesting that CT within 6 hours of symptoms onset is nearly 100% sensitive for the presence of SAH. A more recent article confirmed similar findings in a nonacademic setting with staff radiologists.

    It is important to note, however, that not all spontaneous subarachnoid hemorrhages are due to aneurysmal bleeding. Nonaneurysmal bleeding occurs in 15% of diagnosed subarachnoid hemorrhages. Causes of these include paramesencephalic hemorrhage (10%), arterial dissection, cerebral arteriovenous malformation, dural arteriovenous fistulas, vascular lesions around the spinal cord, among other rare conditions. The larger of the group, paramesencephalic hemorrhage, has a good prognosis with little risk of rebleeding and mortality. The question therefore remained whether or not pathologies unable to be detected by CTA are clinically relevant.

    In 2014 a paper was published assessing the outcomes of patients who had > 5 RBCs on their LP after initial negative CT and subsequent negative CT angiography.  The study successfully followed 181 patients meeting these inclusion criteria for 53 months. None of the patients had a subsequent bleed or new lesion found on further imaging, although one patient was eventually diagnosed with vasculitis when they returned 2 weeks later with an intraparenchymal hemorrhage and hemiparesis. As such, data suggests that seeking out the subarachnoid hemorrhage that does not have an etiology identifiable by angiography may be unnecessary when it comes to clinical outcomes.

    For now, the current ACEP Clinical Policy (from 2008) states that patients arriving with an acute-onset severe headache with a negative head CT require lumbar puncture to rule out subarachnoid hemorrhage. With more data supporting the utilization of CTA instead of performing an LP.

    Sources:

    McCormack RF, Hutson A. Can computed tomography angiography of the brain replace lumbar puncture in the evaluation of acute-onset headache after a negative noncontrast cranial computed tomography scan? Acad Emerg Med. 2010 Apr;17(4):444-51. doi: 10.1111/j.1553-2712.2010.00694.x. Review. PubMed PMID: 20370785.

    Perry JJ, Stiell IG, Sivilotti ML, Bullard MJ, Emond M, Symington C, Sutherland J, Worster A, Hohl C, Lee JS, Eisenhauer MA, Mortensen M, Mackey D, Pauls M, Lesiuk H, Wells GA. Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study. BMJ. 2011 Jul 18;343:d4277. doi: 10.1136/bmj.d4277. PubMed PMID: 21768192; PubMed Central PMCID: PMC3138338.

    Blok KM, Rinkel GJ, Majoie CB, Hendrikse J, Braaksma M, Tijssen CC, Wong YY, Hofmeijer J, Extercatte J, Kerklaan B, Schreuder TH, ten Holter S, Verheul F, Harlaar L, Pruissen DM, Kwa VI, Brouwers PJ, Remmers MJ, Schonewille WJ, Kruyt ND, Vergouwen MD. CT within 6 hours of headache onset to rule out subarachnoid hemorrhage in nonacademic hospitals.Neurology. 2015 May 12;84(19):1927-32. doi: 10.1212/WNL.0000000000001562. Epub 2015 Apr 10. PubMed PMID: 25862794.

    Flaherty ML, Haverbusch M, Kissela B, Kleindorfer D, Schneider A, Sekar P, Moomaw CJ, Sauerbeck L, Broderick JP, Woo D.Perimesencephalic subarachnoid hemorrhage: incidence, risk factors, and outcome. J Stroke Cerebrovasc Dis. 2005 Nov-Dec;14(6):267-71. PubMed PMID: 16518463; PubMed Central PMCID: PMC1388255.

    Kumar MR, Agrawal A. Nonaneurysmal subarachnoid hemorrhage. J Pak Med Stud. 2013; 3(1):24-27

    Thomas LE, Czuczman AD, Boulanger AB, Peak DA, Miller ES, Brown DF, Marill KA. Low risk for subsequent subarachnoid hemorrhage for emergency department patients with headache, bloody cerebrospinal fluid, and negative findings on cerebrovascular imaging. J Neurosurg. 2014 Jul;121(1):24-31. doi: 10.3171/2014.3.JNS132239. Epub 2014 Apr 18. PubMed PMID: 24745707.

    Edlow JA, Panagos PD, Godwin SA, Thomas TL, Decker WW; American College of Emergency Physicians. Clinical policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with acute headache. Ann Emerg Med. 2008 Oct;52(4):407-36. doi: 10.1016/j.annemergmed.2008.07.001. PubMed PMID: 18809105.

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