Classification of non-aneurysmal subarachnoid haemorrhage: CT correlation to the clinical outcome

Current status of perimesencephalic non-aneurysmal subarachnoid hemorrhage

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) is a distinctive disease, representing SAH centered in perimesencephalic cisterns, with negative angiography findings. In recent years, the number of patients with PNSAH has increased significantly; however, the knowledge of PNSAH is insufficient. Therefore, we performed a review of the literature from a PubMed search and recounted our understanding of PNSAH. In this review, we summarized that current high-resolution computed tomography angiography is an acceptable replacement for digital subtraction angiography to rule out aneurysms in PNSAH with strict criteria. The current hypothesis about the etiology of PNSAH is that there is deep vein rupture from aberrant venous anatomy and increased intracranial venous pressure. PNSAH is associated with mild symptoms and lower rates of hydrocephalus and symptomatic vasospasm. For PNSAH, conservative treatment has been the mainstream treatment. PNSAH has a benign clinical course and an excellent prognosis; in long-term follow-up, re-bleeding and death were uncommon.

Retrospective 6 month-outcomes and prognostic factors following spontaneous angiogram-negative non-perimesencephalic subarachnoid hemorrhage

Our objective was to analyze functional outcomes and prognostic factors in patients suffering from angiogram-negative non-perimesencephalic subarachnoid hemorrhage (non-PMH). In total, 1601 patients presenting with spontaneous SAH between January 2009 to December 2019 admitted to our institution were reviewed. Among them, 51 patients with angiogram negative non-perimesencephalic subarachnoid hemorrhage were analyzed. We divided patients into groups according to hemorrhage pattern and duration. Prognostic factors were assessed according to initial neurologic grade, early hydrocephalus, fisher grade, and duration of hemorrhage. Outcomes were assessed according to the modified Rankin Scale after 6 months. Overall, 41 patients (80.3%) with angiogram-negative non-PMH achieved a favorable outcome. In univariate analysis, good initial neurologic grade, absence of early hydrocephalus, non-Fisher-type 3 bleeding pattern, and short term hemorrhage (blood wash out <7 days after onset) duration were significantly associated with a favorable outcome. In multivariate analysis, a non-Fisher-type 3 hemorrhagic pattern (p < 0.05) and good initial neurologic state (p < 0.01) were independent predictors of favorable outcomes in angiogram-negative non-PMH patients. Patients with angiogram-negative non-PMH generally had favorable outcomes. A non-Fisher-type 3 hemorrhagic pattern and good initial neurologic state were prognostic factors of a favorable outcome in non-PMH. Furthermore, patients with long-term SAH were more likely to develop hydrocephalus. Evaluating the pattern and duration of subarachnoid hemorrhage may allow better prediction of outcomes in patients with angiogram negative and non-PMH.

Cannabis Use and Increased Nonaneurysmal Subarachnoid Hemorrhage in the Past Decade

OBJECTIVE

Spontaneous subarachnoid hemorrhage is often due to rupture of an intracranial aneurysm, but some patients present with no identifiable source. Increased incidence of nonaneurysmal subarachnoid hemorrhage (naSAH) has been reported over time.

METHODS

We performed a retrospective analysis of naSAH from 2008-2017 to determine the rate of naSAH change over time and its association with cannabis use. Univariable and multivariable regression analyses were performed to study the trend over time, radiographic patterns of hemorrhage, and clinical outcome at the time of discharge. In addition, we compared the rate of naSAH with the rate of aneurysmal SAH (aSAH) to adjust for changes in hospital volume and prevalence/reporting of cannabis use in the population over time.

RESULTS

A total of 86 naSAH and 328 aSAH patients were identified, with an increase in naSAH over time compared with aSAH (P = 0.0034). Increased cannabis use was associated with naSAH (odds ratio [OR] 2.1, 95% confidence interval 1.1, 4.1, P = 0.035) but not aSAH over time. Cannabis use was also associated with different subarachnoid hemorrhage patterns (P = 0.0065) in naSAH. Multivariable analysis demonstrated good neurologic outcome after naSAH to be inversely associated with cocaine use (OR 0.008 [0.002-0.4]), ventriculostomy placement (OR 0.004 [0.03-0.50]), and anticoagulant use (OR 0.016 [0.003-0.54]) but not with cannabis use.

CONCLUSIONS

As cannabis use becomes more prevalent with legalization, it is important to further investigate this association with spontaneous SAH.

Familial Predisposition and Differences in Radiographic Patterns in Spontaneous Nonaneurysmal Subarachnoid Hemorrhage

BACKGROUND

Subarachnoid hemorrhage (SAH) from an intracranial aneurysmal rupture is the most common nontraumatic etiology for SAH, but up to 15% of patients with SAH have no identifiable source.

OBJECTIVE

To assess familial predisposition to spontaneous nonaneurysmal SAH (naSAH) and to evaluate whether family history affects the severity of presentation and prognosis of this condition.

METHODS

We conducted a retrospective analysis of all spontaneous SAH with negative digital subtraction angiography from 2004 to 2018. Patients were divided into 2 groups: patients with first- or second-degree relatives with intracranial aneurysms and patients with no family history. Univariate and multivariate regression analyses were used to study patient presentation, radiographic patterns of hemorrhage, and clinical outcome.

RESULTS

A total of 100 patients met the inclusion criteria. There were no individuals with family history of naSAH. A total of 15 patients (15%) had at least one family member with an intracranial aneurysm, of which 12 (12%) presented as SAH. Patients without family history had a higher percentage of perimesencephalic presentation, whereas those with family history had a higher percentage of nonperimesencephalic SAH presentation (47% vs 13%, odds ratio [OR] 0.17 [95% CI 0.04, 0.81]).

CONCLUSION

We found a high rate of family history of intracranial aneurysms in patients who presented with naSAH. Although there was no difference in clinical outcome in patients with and without family history, there appears to be a higher percentage of nonperimesencephalic radiographic patterns of SAH in those with family history, suggesting possible different etiologies of these hemorrhages.

Novel Subgroups in Subarachnoid Hemorrhage and Their Association With Outcomes-A Systematic Review and Meta-Regression

Background and Purpose: Subarachnoid hemorrhage (SAH) has long been classified into two main forms, aneurysmal SAH (aSAH) and non-aneurysmal SAH (naSAH), but the related risk factors for aSAH and naSAH are heterogeneous. Our objective was to determine the risk factors for SAH of known or unknown origin with respect to diagnostic evaluation in a large patient cohort. We sought to determine whether our classification system can further predict middle long-term stroke and death. Methods: We performed a systematic review and meta-analysis to identify risk factors for each SAH subtype. The discovery phase analyzed 11 risk factors from case studies in the literature. Kruskal-Wallis, Cox regression, logistic regression, and Kaplan-Meier analyses were used to compare the two groups. Results: A total of 14,904 (34.53%) male and 22,801 (52.84%) female patients were eligible for this study. At a median follow-up of 45.6 months, the 5-years overall survival was 97.768% (95% CI: 0.259-0.292) for aSAH patients and 87.904% (95% CI: 1.459-1.643) for naSAH patients. The 10-years survival rate was 93.870% (95% CI: 2.075-3.086) and 78.115% (95% CI: 2.810-3.156), respectively. Multi-risk factor subgroups showed significant intergroup differences. We identified eight risk factors (drugs, trauma, neoplastic, vessels lesion, inflammatory lesion, blood disease, aneurysm, peri-mesencephalic hemorrhage) using logistic regression, which were optimally differentiated among the aSAH [aSAH-S (AUC: 1), a-d-SAH (AUC: 0.9998), aSAH-T (AUC: 0.9199), aSAH-N (AUC: 0.9433), aSAH-V (AUC: 1), aSAH-I (AUC: 0.9954), a-bd-SAH (AUC: 0.9955)] and naSAH [na-pmSAH (AUC: 0.9979), na-ni-ivl-SAH (AUC: 1), na-t-SAH (AUC: 0.9997), na-ne-SAH (AUC: 0.9475), na-d-SAH (AUC: 0.7676)] subgroups. These models were applied in a parallel cohort, showing eight risk factors plus survival rates to predict the prognosis of SAH. Conclusions: The classification of risk factors related to aSAH and naSAH is helpful in the diagnosis and prediction of the prognosis of aSAH and naSAH patients. Further validation is needed in future clinical applications.

Subarachnoid haemorrhage with negative initial neurovascular imaging: a systematic review and meta-analysis

Background

In patients with spontaneous subarachnoid haemorrhage (SAH), a vascular cause for the bleed is not always found on initial investigations. This study aimed to systematically evaluate the delayed investigation strategies and clinical outcomes in these cases, often described as “non-aneurysmal” SAH (naSAH).

Methods

A systematic review was performed in concordance with the PRISMA checklist. Pooled proportions of primary outcome measures were estimated using a random-effects model.

Results

Fifty-eight studies were included (4473 patients). The cohort was split into perimesencephalic naSAH (PnaSAH) (49.9%), non-PnaSAH (44.7%) and radiologically negative SAH identified on lumbar puncture (5.4%). The commonest initial vascular imaging modality was digital subtraction angiography. A vascular abnormality was identified during delayed investigation in 3.9% [95% CI 1.9–6.6]. There was no uniform strategy for the timing or modality of delayed investigations. The pooled proportion of a favourable modified Rankin scale outcome (0–2) at 3–6 months following diagnosis was 92.0% [95% CI 86.0–96.5]. Complications included re-bleeding (3.1% [95% CI 1.5–5.2]), hydrocephalus (16.0% [95% CI 11.2–21.4]), vasospasm (9.6% [95% CI 6.5–13.3]) and seizure (3.5% [95% CI 1.7–5.8]). Stratified by bleeding pattern, we demonstrate a higher rate of delayed diagnoses (13.6% [95% CI 7.4–21.3]), lower proportion of favourable functional outcome (87.2% [95% CI 80.1–92.9]) and higher risk of complications for non-PnaSAH patients.

Conclusion

This study highlights the heterogeneity in delayed investigations and outcomes for patients with naSAH, which may be influenced by the initial pattern of bleeding. Further multi-centre prospective studies are required to clarify optimal tailored management strategies for this heterogeneous group of patients.

Electronic supplementary material

The online version of this article (10.1007/s00701-019-04025-w) contains supplementary material, which is available to authorized users.

Epileptic seizures and outcome in different subtypes of subarachnoid haemorrhage - Results of a single-center retrospective analysis

BACKGROUND

Symptomatic epileptic seizures are an important complication in subarachnoid haemorrhage (SAH) with a frequency of 0.9-25% with importance for patient outcome. The majority of previous studies investigated the incidence of symptomatic epileptic seizures after aneurysmatic SAH. Here we compared the seizure incidence and its impact on the outcome between non-aneurysmatic and aneurysmatic SAH.

METHODS

We analysed retrospectively 109 consecutive patients with spontaneous, non-traumatic SAH. Patients were divided in three groups (perimesencephalic, non-aneurysmatic and aneurysmatic SAH). All patients received standard-of-care treatment. The occurrence of acute (0-7 days after SAH) and remote symptomatic epileptic seizures (7 days or more after SAH), severity of SAH as well as clinical outcome parameters (modified Rankin scale [mRS]) at discharge and the frequency of in-house complications were assessed. mRS scores were dichotomized in 0-3 vs. 4-6 to stratify for good versus bad outcome.

RESULTS

Perimesencephalic SAH patients did not experience acute seizures whereas non-aneurysmatic and aneurysmatic SAH patients showed acute seizures with similar frequency (9% and 11%, p = 0.23). The frequency of remote symptomatic seizures was similar in all subgroups (12% vs. 9% vs. 7%, p = 0.72). Seizure occurrence was not predictive for a poor outcome (mRS >4; acute seizures: OR 0.35 [95%CI: 0.02-6.96], p = 0.49; remote seizures: OR 1.72 [95%CI: 0.14-20.1], p = 0.67).

CONCLUSIONS

Seizures are important neurologic complications of SAH of all etiologies. Nevertheless, acute as well as remote symptomatic seizures are unrelated to the short-term outcome. These results should be treated as hypothesis generating and require confirmation.

Cerebral Vasospasm-Dependent and Cerebral Vasospasm-Independent Cerebral Infarctions Predict Outcome After Nonaneurysmal Subarachnoid Hemorrhage: A Single-Center Series with 250 Patients

OBJECTIVE

The number of patients with nonaneurysmal subarachnoid hemorrhage (naSAH) has increased during the last decade. Data regarding infarctions in naSAH are still limited. The aim of this study was to identify the rate of cerebral vasospasm (CVS)-dependent and CVS-independent infarctions and their influence on clinical outcomes.

METHODS

Between 1999 and 2015, 250 patients suffering from naSAH were analyzed retrospectively. A delayed infarction was analyzed whether it was associated with CVS (CVS-dependent infarction) or not (CVS-independent).

RESULTS

A total of 36 patients (14%) had cerebral infarctions. CVS was detected in 54 patients (22%), and 15 (6%) of them developed infarctions (CVS-dependent). Infarctions without signs of CVS (CVS-independent) occurred in 21 patients (8%). Overall, 86% of the patients had favorable outcome. Patients without cerebral infarctions had the best outcome (91% favorable outcome, 5% mortality rate). Patients with CVS-independent infarctions (57%) as well as patients with CVS-dependent infarctions (53%) had a favorable outcome less often. The mortality rate was also significantly greater in patients with CVS-independent (19%) and CVS-dependent infarctions (33%). A further independent predictor was anticoagulative therapy, which increased during study period and was associated with nonperimesencephalic blood distribution.

CONCLUSIONS

CVS-dependent and independent infarctions occur in naSAH and contribute to unfavorable outcomes. Whereas CVS-independent infarctions occur in any subgroup, CVS-dependent infarctions seem to be associated with blood pattern (Fisher 3). Anticoagulative therapy seems to be not only a predictor for worse outcome but also for nonperimesencephalic SAH. Accordingly, the proportion of perimesencephalic and nonperimesencephalic SAH changed during the study period (from 2.2:1 to 1:1.7).

Non-aneurysmal subarachnoid hemorrhage in 173 patients: a prospective study of long-term outcome

BACKGROUND AND PURPOSE

In some patients with subarachnoid hemorrhage (SAH) a bleeding source cannot be identified. Perimesencephalic (PM) SAH is assumed to have an excellent outcome. Our objective was to analyze the long-term physical and psychological outcome of patients after non-aneurysmal SAH.

METHODS

One hundred and seventy-three patients met the inclusion criteria. Short-term follow-up 6 months after SAH was assessed according to the modified Rankin Scale (0-2 favorable). A short-form health survey with 36 questions (SF-36) and eight scales was used as questionnaire for long-term follow-up.

RESULTS

Thirty-seven answers were received from the two groups, PM and non-perimesencephalic (NPM) SAH, on average 76 months after ictus (range 1.5-14 years). PM- and NPM-SAH without Fisher grade 3 blood pattern have excellent short-term outcomes. The quality of life (QoL) is significantly reduced after non-aneurysmal SAH, especially in NPM-SAH. In particular, patients with a Fisher 3 blood pattern had significantly higher risks for cerebral vasospasm, delayed cerebral ischaemia, unfavorable outcome, reduced QoL and mortality in short- and long-term follow-up.

CONCLUSIONS

Excluding rolph, only patients with a PM-SAH have a similar QoL at long-term follow-up compared to the standard population. Patients with NPM-SAH have a significantly decreased QoL in long-term follow-up. Furthermore, the Fisher 3 blood pattern group in particular had a significantly worse outcome - at short-term and long-term follow-up. Therefore the NPM-SAH group was stratified into patients with Fisher 3 blood pattern and patients without Fisher 3 in further investigations.

Angiographic assessment of variants of basal vein of Rosenthal in idiopathic subarachnoid hemorrhage

Previous studies have reported the possible contribution of a primitive variant of the basal vein of Rosenthal (BVR) in the cause of idiopathic subarachnoid hemorrhage (ISAH). The purpose of this study was to assess the drainage patterns of the BVR among ISAH patients. The venous phase at cerebral angiography was retrospectively analyzed in 19 patients with ISAH and then compared with patients with unruptured aneurysms as controls. A relationship was found between ISAH and the presence of a primitive variant. However, the venous configuration effect on bleeding is still unknown.

Clinical outcome and prognostic factors of patients with angiogram-negative and non-perimesencephalic subarachnoid hemorrhage: benign prognosis like perimesencephalic SAH or same risk as aneurysmal SAH?

Subarachnoid hemorrhage (SAH) is usually caused by a ruptured intracranial aneurysm. However, in some patients, no source of hemorrhage might be detected despite repeated digital subtraction angiography (DSA). Our objective was to analyze factors influencing the clinical outcome in patients suffering from non-aneurysmal and non-perimesencephalic (NPM) SAH. Between 1999 and 2011, 68 of 1,188 patients with SAH (5.7%) suffered from non-aneurysmal and NPM-SAH. Outcome was assessed according to the modified Rankin Scale (mRS) at 6 months (mRS 0-2 favorable vs. 3-6 unfavorable). In patients with angiogram-negative and NPM-SAH, favorable outcome was achieved in 56 patients (82.4%). In the multivariate analysis, age <65 years and non-Fisher 3 bleeding pattern were significantly associated with favorable outcome. Angiogram-negative and NPM-SAH had good prognoses. Patients with non-Fisher-type 3 bleeding had excellent outcomes similar to patients with perimesencephalic SAH, but patients with Fisher-type 3 bleeding were at risk for poor outcome like aneurysmal SAH patients due to cerebral vasospasm and delayed cerebral ischemia. Age and bleeding type were detected as prognostic factors in the multivariate analysis.

Nonaneurysmal perimesencephalic subarachnoid hemorrhage: diagnosis, pathophysiology, clinical characteristics, and long-term outcome

Patients with nonaneurysmal perimesencephalic subarachnoid hemorrhage (NAPSAH) have no discernible source for the bleeding and generally are considered to have a benign condition. Correctly diagnosing these patients is essential because a missed aneurysm can have catastrophic consequences. Those presenting with NAPSAH have a low risk of complications and better outcome than patients presenting with aneurysmal subarachnoid hemorrhage; however, a limited body of literature suggests that not all of these patients are able to return to their premorbid functional status. Clinical screens of cognitive status, such as the mini-mental status examination, suggest good recovery of these patients, although these tests may lack sensitivity for identifying deficits in this patient population. More comprehensive neuropsychologic testing in some studies has identified deficits in a wide range of cognitive domains at long-term follow-up in patients with NAPSAH. Because these patients often do not lose consciousness (and thus do not have substantial transient global ischemia) and they do not undergo a procedure for aneurysm repair, the cognitive sequelae can be explained by the presence of blood in the subarachnoid space. NAPSAH presents an opportunity to understand the effects of subarachnoid blood in a clinical setting.

Non-aneurysmal non-traumatic subarachnoid hemorrhage: patient characteristics, clinical outcome and prognostic factors based on a single-center experience in 125 patients

BACKGROUND

Subarachnoid hemorrhage (SAH) is mainly caused by ruptured cerebral aneurysms but in up to 15% of patients with SAH no bleeding source could be identified. Our objective was to analyze patient characteristics, clinical outcome and prognostic factors in patients suffering from non-aneurysmal SAH.

METHODS

From 1999 to 2009, data of 125 patients with non-aneurysmal SAH were prospectively entered into a database. All patients underwent repetitive cerebral angiography. Outcome was assessed according to the modified Rankin Scale (mRS) (mRS 0-2 favorable vs. 3-6 unfavorable). Also, patients were divided in two groups according to the distribution of blood in the CT scan (perimesencephalic and non-perimesencephalic SAH).

RESULTS

106 of the 125 patients were in good WFNS grade (I-III) at admission (85%). Overall, favorable outcome was achieved in 104 of 125 patients (83%). Favorable outcome was associated with younger age (P < 0.001), good admission status (P < 0.0001), and absence of hydrocephalus (P = 0.001).73 of the 125 patients suffered from perimesencephalic SAH, most patients (90%) were in good grade at admission, and 64 achieved favorable outcome.52 of the 125 patients suffered from non-perimesencephalic SAH and 40 were in good grade at admission. Also 40 patients achieved favorable outcome.

CONCLUSIONS

Patients suffering from non-aneurysmal SAH have better prognosis compared to aneurysm related SAH and poor admission status was the only independent predictor of unfavorable outcome in the multivariate analysis. Patients with a non-perimesencephalic SAH have an increased risk of a worse neurological outcome. These patients should be monitored attentively.

Nontraumatic convexity subarachnoid hemorrhage: different etiologies and outcomes

BACKGROUND

Nontraumatic convexity subarachnoid hemorrhage (cSAH) is a rarely reported condition with multiple etiologies. We report the clinical presentation, imaging findings, etiologies, and long-term outcomes of a case series of cSAH.

METHODS

We retrospectively analyzed consecutive cases of cSAH, admitted at a Stroke Unit of a tertiary hospital (January 2006 to March 2012). Recorded variables were demographics, clinical presentation, complementary investigation, etiology, and outcome.

RESULTS

We included 15 patients (9 men, median age of 65 years), 7% of the 210 nontraumatic SAH patients in this period. The most common clinical manifestation was a focal neurologic deficit. Predominant location of the cSAH was frontal. In 5 cases, there was a clinical significant internal carotid artery (ICA) atheromatous stenosis, ipsilateral to cSAH. Two patients had a possible cerebral amyloid angiopathy (CAA) at presentation. There were 2 cases of reversible cerebral vasoconstriction syndrome, 1 cerebral venous thrombosis, 2 dural fistulae, and 3 undetermined. Short-term outcomes were good in most patients. At follow-up (24.3 months), 2 of the patients with undetermined etiology had a lobar hematoma conferring a severe disability, and the diagnosis of CAA was made. There were no other relevant events or added disability in the other patients.

CONCLUSIONS

Significant ICA atherosclerotic stenosis was the most frequent cause of cSAH in our series, reinforcing that cSAH should prompt vascular imagiological evaluation including cervical vessels. Outcomes in cSAH seem to be related to etiology. Patients with undetermined etiology should be followed up because cSAH may be the first manifestation of CAA.