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Managing aneurysmal subarachnoid hemorrhage: It takes a team

Cleveland Clinic Journal of Medicine. 2015 March;82(3):177-192 | 10.3949/ccjm.82a.14021
March 1, 2015|Cleveland Clinic Journal of Medicine
Airton Leonardo de Oliveira Manoel, MD;David Turkel-Parrella, MD;Abhijit Duggal, MD;Amanda Murphy, MD, PhD;Victoria McCredie, MD, FRCPC;Thomas R. Marotta, MD, FRCPC
Author and Disclosure Information

Airton Leonardo de Oliveira Manoel, MD
Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Department of Medical Imaging, Interventional Neuroradiology, and Department of Critical Care, Trauma and Neurosurgical Intensive Care Unit, St. Michael’s Hospital, Toronto, ON, Canada

David Turkel-Parrella, MD
Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Department of Medical Imaging, Interventional Neuroradiology, and Division of Neurosurgery, St. Michael’s Hospital, Toronto, ON, Canada

Abhijit Duggal, MD
Medical Intensive Care Unit, Department of Pulmonary, Allergy, and Critical Care, Respiratory Institute, Cleveland Clinic; Assistant Professor of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH

Amanda Murphy, MD, PhD
Faculty of Medicine and Department of Medical Imaging, University of Toronto, Toronto, ON, Canada

Victoria McCredie, MD, FRCPC
Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Department of Critical Care, Sunnybrook Health Sciences Centre, Toronto, ON, Canada

Thomas R. Marotta, MD, FRCPC
Faculty of Medicine and Department of Medical Imaging, University of Toronto, Toronto, ON, Canada; Department of Medical Imaging, Interventional Neuroradiology, St. Michael’s Hospital, Toronto, ON, Canada

Address: Airton Leonardo de Oliveira Manoel, MD, Trauma and Neurosurgical Intensive Care Unit, St. Mi-chael’s Hospital, 30 Bond Street, Toronto, ON, Canada M5B 1W8; e-mail: airtonleo.manoel@gmail.com

ABSTRACTPatients with aneurysmal subarachnoid hemorrhage are at high risk of complications, including rebleeding, delayed cerebral ischemia, cerebral infarction, and death. This review presents a practical approach for managing this condition and its complications.

KEY POINTS

  • The key symptom is the abrupt onset of severe headache, commonly described as “the worst headache of my life.
  • Computed tomography without contrast should be done promptly when this condition is suspected.
  • Outcomes are improved when patients are managed in a high-volume center with a specialized neurointensive care unit and access to an interdisciplinary team.
  • Early aneurysm repair by surgical clipping or endovascular coiling is considered the standard of care and is the best strategy to reduce the risk of rebleeding.
  • Medical and neurologic complications are extremely common and include hydrocephalus, increased intracranial pressure, seizures, delayed cerebral ischemia, hyponatremia, hypovolemia, and cardiac and pulmonary abnormalities.

Aneurysmal subarachnoid hemorrhage is a devastating condition, with an estimated death rate of 30% during the initial episode.1,2 Approximately the same number of patients survive but leave the hospital with disabling neurologic deficits.3

However, better outcomes can be achieved by systems that are able to work as a team on the collective goal of quick intervention to secure the ruptured aneurysm, followed by the implementation of measures to minimize secondary brain injury. Although the search for new diagnostic, prognostic, and therapeutic modalities continues, it is clear that there exists no “silver bullet” that will help all patients. Instead, it is the systematic integration and application of small advances that will ultimately maximize the patient’s chances of survival and neurologic recovery.

This review focuses on the management of aneurysmal subarachnoid hemorrhage and its systemic and neurologic complications.

ANEURYSM IS THE MOST COMMON CAUSE OF SUBARACHNOID BLEEDING

Aneurysmal subarachnoid hemorrhage, ie, rupture of an intracranial aneurysm, flooding  the subarachnoid space with blood, affects about 24,000 Americans each year.1,2 A ruptured aneurysm is the most common cause of subarachnoid hemorrhage, accounting for about 85% of cases. Less common causes include idiopathic benign perimesencephalic hemorrhage, arteriovenous malformation, dural arteriovenous fistula, and hemorrhagic mycotic aneurysm. These have their own natural history, pathophysiology, and specific treatment, and will not be addressed in this article.

Risk factors for aneurysmal subarachnoid hemorrhage include having a first-degree relative who had the disease, hypertension, smoking, and consuming more than 150 g of alcohol per week.4

CLINICAL PRESENTATION AND DIAGNOSIS

The key symptom of aneurysmal subarachnoid hemorrhage is the abrupt onset of severe headache that peaks in intensity over 1 hour,5 often described as “the worst headache of my life.” Headache is accompanied by brief loss of consciousness in 53% of cases (conversely, nearly half of patients maintain normal mental status), by nausea or vomiting in 77%, and by meningismus (neck pain or stiffness) in 35%.6

These clinical manifestations and risk factors have been incorporated into a decision rule:

Obtain brain imaging if the patient has acute headache reaching maximal intensity within 1 hour, associated with any of the following factors:

  • Age 40 or older
  • Neck pain or stiffness
  • Witnessed loss of consciousness
  • Onset during exertion
  • “Thunderclap” headache (ie, instantly peaking pain)
  • Limited neck flexion on examination.5

This decision rule has nearly 100% sensitivity for aneurysmal subarachnoid hemorrhage in clinical practice.5 All patients require brain imaging if they have a severe headache plus either abnormal neurologic findings (eg, a focal neurologic deficit) or a history of cerebral aneurysm.

Emergency physicians should have a low threshold for ordering noncontrast computed tomography (CT) of the head in patients with even mild symptoms suggesting aneurysmal subarachnoid hemorrhage. Failure to order CT is the most common diagnostic error in this situation.6 CT performed within 6 hours of headache onset is nearly 100% sensitive for this condition,7 but the sensitivity falls to 93% after the first 24 hours and to less than 60% after 5 days.8 In patients who have symptoms highly suggestive of aneurysmal subarachnoid hemorrhage but a normal CT, lumbar puncture is the next diagnostic step.

There are two alternatives to CT followed by lumbar puncture: ie, noncontrast CT followed by CT angiography,9,10 and magnetic resonance imaging followed by magnetic resonance angiography. In patients with suspicious clinical symptoms but negative CT results, CT followed by CT angiography can rule out aneurysmal subarachnoid hemorrhage with a 99% probability.9,10 However, CT followed by lumbar puncture remains the standard of care and carries a class I recommendation in the American Heart Association guidelines for ruling out subarachnoid hemorrhage.5

GRADING THE SEVERITY OF SUBARACHNOID HEMORRHAGE

Age, the thickness of the blood layer in the subarachnoid space, intraventricular hemorrhage and the findings of the neurologic examination at presentation are predictors of long-term outcomes in aneurysmal subarachnoid hemorrhage (Figure 1).

Figure 1. Computed tomographic grading scale (no contrast, trans-verse plane). The thickness of subarachnoid blood is an independent risk factor for angiographic vasospasm and delayed cerebral ischemia (see Table 1 ). (A) Modified Fisher 3: a thick layer of subarachnoid blood filling multiple basal cisterns. (B) Modified Fisher 4: bilateral intra-ventricular hemorrhage (blue arrow), and the tip of an external ventricu-lostomy drain (red arrow). (C) Modified Fisher 1. (D) Thick subarachnoid layer centered in the left sylvian fissure with rightward subfalcine herniation.

Different grading systems used in clinical practice are based on the findings on the initial neurologic examination and on the initial noncontrast CT (ie, the thickness of the blood, and whether intraventricular hemorrhage is present). Among the most widely used are those developed by Hunt and Hess12 and by the World Federation of Neurological Surgeons11 (WFNS), and the CT grading scales (Fisher13 or its modified version14)  (Tables 1 and 2). With either the Hunt and Hess scale or the WFNS scale, the higher the score, the worse the patient’s probable outcome. Scores on both Fisher scales correlate with the risk of angiographic vasospasm. The higher the grade, the higher the risk of angiographic vasospasm.

The VASOGRADE score—a combination of the WFNS score and the modified Fisher scale—stratifies patients at risk of delayed cerebral ischemia, allowing for a tailored monitoring strategy.15 There are three variations:

  • VASOGRADE green—Modified Fisher 1 or 2 and WFNS 1 or 2
  • VASOGRADE yellow—Modified Fisher 3 or 4 and WFNS 1, 2, or 3
  • VASOGRADE red—WFNS 4 or 5. 

After the initial bleeding event, patients with aneurysmal subarachnoid hemorrhage are at high risk of delayed systemic and neurologic complications, with poor functional outcomes. Delayed cerebral ischemia holds the greatest risk of an unfavorable outcome and ultimately can lead to cerebral infarction, disability, and death.6,7

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