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Section 3.6

Acute Subarachnoid Hemorrhage

NOTES on this recommendation

  • This recommendation is for patients with subarachnoid hemorrhage (SAH). It applies to the initial assessment in the emergency department within the first few hours of patient arrival.
  • Treatment and management of hemorrhagic stroke patients is outside the scope of these recommendations.
  • Symptoms include sudden onset of severe headache (sometimes described as “thunderclap headache”) that patients will often characterize as the worst of their life. The headache of SAH is usually associated with nausea, vomiting, meningismus and photophobia and can also be associated with altered level of consciousness. Signs on physical examination vary depending on the location of the aneurysm and the extent of the hemorrhage as well as whether there is intraventricular of intracerebral extension of the subarachnoid hemorrhage. Physical signs can include diminished level of consciousness, cranial nerve palsy, hemiparesis and subhyaloid hemorrhage on fundoscopic exam, but it is important to note that patients with acute SAH often have a NORMAL neurological examination, so the absence of physical findings should not alter the index of suspicion raised by the clinical presentation.

Patients with aneurysmal subarachnoid hemorrhage should be treated as a medical emergency and evaluated immediately by physicians with expertise in stroke management [Evidence Level B].

  1. Patients with suspected subarachnoid hemorrhage should have a non-contrast CT scan as soon as possible after hospital arrival to confirm the diagnosis [Evidence Level B].
  2. Patients with a strongly suggestive clinical history of subarachnoid hemorrhage, but negative non-contrast CT scan as reported by a radiologist, should undergo lumbar puncture for cerebrospinal fluid analysis. Xanthochromia evaluation may be more sensitive after a delay of 12 hours from symptom onset, but such a delay may not be practical or clinically appropriate [Evidence Level B].
  3. Cerebrospinal fluid analysis for xanthochromia by spectrophotometry is preferable to visual inspection, but is not routinely available in Canada [Evidence Level B].
  4. Patients with subarachnoid hemorrhage should undergo vascular imaging of the brain. High-quality noninvasive CT angiography may be preferable to catheter angiography as an initial investigation [Evidence Level B].
  5. Patients with subarachnoid hemorrhage should have an urgent consultation with a neurosurgeon [Evidence Level B].
  6. Patients with subarachnoid hemorrhage and negative non-invasive vascular imaging should be considered for further imaging with catheter angiography [Evidence Level C].
  7. Patients with aneurysmal subarachnoid hemorrhage and CT evidence of hydrocephalus that is clinically symptomatic should undergo urgent placement of an external ventricular drain or other cerebrospinal fluid diversion technique [Evidence Level B].
  8. Patients who present within 96 hours of a subarachnoid hemorrhage and have an adequate blood pressure should immediately be started on nimodipine 60 mg every four hours by mouth for 14 to 21 days [Evidence Level A].
  9. Patients with subarachnoid hemorrhage should have their blood pressure closely monitored and maintained as normotensive [Evidence Level B]. Treatment for high blood pressure should be initiated while the aneurysm is unsecured to reduce the risk of hypertension-induced rebleeding [Evidence Level B].
  10. Patients with an aneurysmal subarachnoid hemorrhage should have the aneurysm secured urgently by endovascular coiling or microsurgical clipping within 24 to 48 hours [Evidence Level B]. For patients with poor prognosis for neurological recovery, an initial course of supportive non-surgical management may be appropriate [Evidence Level B].
  11. For subarachnoid hemorrhage patients with intraparenchymal extension at the time the aneurysm is secured, urgent evacuation of the hematoma should be considered [Evidence Level C].
  12. Decisions regarding modality of treatment should be based on patient-specific characteristics, which include consideration of patient age, clinical grade, morphology of the aneurysm, medical co-morbidity and institutional experience and resources [Evidence Level B]. However, the International Subarachnoid Aneurysm Trial (ISAT), which studied subarachnoid hemorrhage patients who were technically eligible for either treatment, demonstrated that outcomes were better among those treated by endovascular methods than by microsurgery [Evidence Level A].
  13. Patients with aneurysmal subarachnoid hemorrhage should receive venous thromboembolism prophylaxis [Evidence Level A].
    Refer to section 4.2 for additional information.
    Rationale

    Subarachnoid hemorrhage is a common and often catastrophic neurosurgical emergency that is prevalent in approximately seven percent of adults with stroke, and also in children. Recent mortality rates in Canada for patients with subarachnoid hemorrhage are just over 40 percent within 30 days of the event, and account for prolonged hospital lengths of stay. Over the past decade, several advances have been made in early treatment of subarachnoid hemorrhage, including endovascular techniques. Prompt recognition and access to expert medical professionals may reduce mortality and morbidity and improve long-term outcomes.

    System Implications
    • Awareness and education for physicians and nursing staff to recognize hemorrhagic stroke as a medical emergency.
    • Protocols for rapid access to neurosurgical specialists for hemorrhagic patient management, including rapid referral process if neurosurgical services not available within the initial treating hospital.
    Performance Measures
    1. Risk-adjusted mortality rates for subarachnoid hemorrhage in-hospital, 30-day and one year (core).
    2. Percentage of subarachnoid hemorrhage patients who receive a consult to a neurosurgeon within 24 hours of hospital arrival.
    3. Percentage of subarachnoid hemorrhage patients who receive a CT scan or MRI within 24 hours of hospital arrival
    4. Rebleeding rate for subarachnoid hemorrhage patients (stratified by whether patient underwent surgical or endovascular intervention) within 7 days and 30 days of hospital presentation.

    Measurement Notes

    • Risk adjustment should include age, gender, and initial stroke severity scores, as well as co-morbidities
    Implementation Resources and Knowledge Transfer Tools
    Summary of the Evidence

    Subarachnoid hemorrhage (SAH) is a medical emergency with potentially devastating effects of early mortality or significant morbidity. The Public Health Agency of Canada reports mortality rates of 2.9 per 100,000 in 2003, with an annual mortality rate of 42 percent from SAH.85 The HUNT study of risk factors for SAH found that systolic and diastolic blood pressure were strong predictors of aneurysmal SAH, and there was a substantially increased risk associated with smoking.245 However, high body mass was associated with reduced risk of aneurysmal SAH. Adequate blood pressure control has been found as an independent risk factor in reducing the severity of SAH, and uncontrolled hypertension has been found to be a predictor of poorer outcomes. 246 Eden and colleagues reported that the overall age-adjusted risk ratio for SAH in women compared to men was 1.74 (95% CI 1.16, 2.62).247 Overall in-hospital mortality was 32.2 percent, and no ethnic differences were observed for discharge disability or in-hospital mortality.

    Lovelock and colleagues examined trends in case-fatality with subarachnoid hemorrhage through a systematic review and by comparing results from the Oxford Community Stroke Project (1981 to 1986) and the Oxford Vascular Study(2002 and 2008). 248 The analysis did not show reductions in incidence of SAH (RR = 0.79, 95% confidence interval [CI] 0.48–1.29, p = 0.34) and in 30-day case-fatality (RR = 0.67, 95% CI 0.39–1.13, p = 0.14) in the Oxford Vascular Study vs. Oxford Community Stroke Project, but there was a decrease in overall mortality (RR = 0.47, 0.23–0.97, p = 0.04). Following adjustment for age and baseline SAH severity, patients surviving to hospital had reduced risk of death or dependency (modified Rankin score > 3) at 12 months in the Oxford Vascular Study (RR = 0.51, 0.29–0.88, p = 0.01). Among 32 studies covering 39 study periods from 1980 to 2005, seven studied time trends within single populations. Unadjusted case-fatality fell by 0.9 percent per annum (0.3–1.5, p = 0.007) in a meta-analysis of data from all studies, and by 0.9 percent per annum (0.2–1.6%, p = 0.01) within the seven population studies. The authors conclude that mortality due to subarachnoid hemorrhage fell by about 50 percent in their study population over the last two decades, due mainly to improved outcomes in cases surviving to reach hospital.

     

    Timing of aneurysm surgery has been addressed in several nonrandomized clinical series. Kassell et al. observed no preoperative rebleeds in 27 patients with early (less than three days after subarachnoid hemorrhage) surgery compared with seven of 24 patients (29%) with late surgery.249 At surgery, both groups had the same intraoperative hemorrhage rate (26%). The International Cooperative Study on the Timing of Aneurysm Surgery analyzed management comparison in 3521 patients, of whom 83 percent underwent surgical repair of the ruptured aneurysm.252 Timing of surgery after subarachnoid hemorrhage was significantly related to the likelihood of preoperative rebleeding (0 to 3 days, 5.7%; 4 to 6 days, 9.4%; 7 to 10 days, 12.7%; 11 to 14 days, 13.9%; and 15 to 32 days, 21.5%). Postoperative rebleeding did not differ among time intervals (1.6 percent overall). Nevertheless, there was no significant difference in overall outcome in this study related to timing of surgery.

    In recent years there has been a trend toward early surgery for ruptured aneurysms, especially in good- and moderate-grade patients. In addition, early surgery facilitates the aggressive therapy of vasospasm.

    deGans and colleagues conducted a review of timing of aneurysm surgery and dentified were 1 randomized clinical trial and only 10 out of 268 observational studies (assessing a total of 1814 patients) that fulfilled a set of minimum requirements for methodological quality.250 In the trial, the RR of poor outcome was 0.42 (95% CI, 0.17-1.04) for patients planned for early surgery and 1.07 (95% CI, 0.56-2.05) for intermediate surgery. The analysis of the observational study data found the RR of poor outcome for patients in good clinical condition at admission was 0.41 (95% CI, 0.34-0.51) for early surgery and 0.47 (95% CI, 0.32-0.69) for intermediate surgery. For patients in poor clinical condition at admission, the RR of poor outcome was 0.84 (95% CI, 0.67-1.05) for early surgery and 0.54 (95% CI, 0.24-1.22) for intermediate surgery.  Regardless of surgical timing, early referral to centers with facilities for intensive care of patients with subarachnoid hemorrhage is essential, since many therapies need to be initiated in the acute period.182

     

     

    The most common and relied upon diagnostic tool for SAH is a non-contrast CT of the brain. Studies have reported that the sensitivity of the CT will decrease as the time from symptom onset to scan increases. The ASA guidelines for SAH (2009) report In the first 12 hours after SAH, the sensitivity of CT for SAH is 98 percent to 100 percent, declining to 93 percent at 24 hours and to 57 percent to 85 percent six days after SAH (page 1000). 51

    The International Subarachnoid Aneurysm Trial (ISAT) was a randomized controlled trial that compared endovascular treatment with neurosurgical treatment in patients with aneurysmal subarachnoid

    hemorrhage.252 ISAT enrolled 2143 patients with ruptured intracranial aneurysms and randomly assigned them to neurosurgical clipping (n=1070) or endovascular treatment by detachable platinum coils (n=1073). Clinical outcomes were assessed at two months and at one year with interim ascertainment of rebleeds and death. The primary outcome was the proportion of patients with a modified Rankin scale score of 3–6 (dependency or death) at one year. Trial recruitment was stopped by the steering committee after a planned interim analysis (published 2002).252 Analysis was per protocol. Final analysis was completed after all patients completed the one-year follow-up (2005). 253 Secondary outcomes included rebleeding from the treated aneurysm and risk of seizures.

    The one-year ISAT outcomes are reported for 1063 of the 1073 patients allocated to endovascular treatment, and 1055 of the 1070 patients allocated to neurosurgical treatment.253 Two hundred and fifty (23.5%) of 1063 patients allocated to endovascular treatment were dead or dependent at one year, compared with 326 (30.9%) of 1055 patients allocated to neurosurgery, an absolute risk reduction of 7.4 percent (95% CI 3.6-11.2, p=0.0001). The early survival advantage was maintained for up to seven years and was significant (log rank p=0.03). The risk of epilepsy was substantially lower in patients allocated to endovascular treatment, but the risk of late rebleeding was higher. The study concluded that endovascular coiling, compared with neurosurgical clipping, for ruptured intracranial aneurysms that were anatomically suitable for either procedure leads to a significant reduction in the relative risk of death or dependency of 23.9 percent (12.4-33.9). This equates to an absolute risk reduction of 7.4 percent (3.6-11.2), which is equivalent to 74 patients avoiding death or dependency at one year for every 1000 patients treated.

     

    Recurrent hemorrhage remains a serious consequence of aneurysmal subarachnoid hemorrhage, with a case-fatality rate of approximately 70 percent for persons who rebleed. In recent years improved diagnosis of subarachnoid hemorrhage and rapid referral to specialized centers have delineated a distinct pattern of rebleeding compared with older studies. In the prospective Cooperative Aneurysm Study rebleeding was maximal (4%) on the first day after subarachnoid hemorrhage and then constant at a rate of one percent to two percent per day over the subsequent four weeks.251 Several prospective follow-up cohorts have demonstrated that the risk of rebleeding with conservative therapy is between 20 percent and 30 percent for the first month after hemorrhage and then stabilizes at a rate of approximately three percent per year.51