Idiopathic subarachnoid hemorrhage: a multicentre series of 220 patients

Non-Aneurysmal Perimesencephalic Subarachnoid Hemorrhage: A Literature Review

Spontaneous non-aneurysmal subarachnoid haemorrhage (NAPMSAH) (addressing point 1) is a relatively rare occurrence in clinical settings as it is rarely misdiagnosed and usually involves a significantly better prognosis than the classical aneurysmal pattern. We hereby focused on a comprehensive analysis of this distinct pathological entity with the purpose of analysing possible pathophysiological entities, outcomes and treatment options involving this diagnosis with a focus on demographical, epidemiological and clinical data. The clinical setting includes focal neurological signs related to the anatomical structures, while computer tomography followed by tomographic angiography are the most common diagnosis tools, with a typical hyperdense lesion involving the midbrain, fourth ventricle and subthalamic areas without an angiographic correspondent, such as an aneurysmal pathology. Further investigations can also be used to highlight this diagnosis, such as interventional angiography or magnetic resonance imaging. Given the rarity of this condition and its relatively better prognosis, treatment options usually remain conservative. In the present review, the main characteristics of NAPMSAH are discussed.

Warfarin-induced isolated spontaneous subarachnoid hemorrhage: Rare case report

Introduction and importance

Subarachnoid hemorrhage (SAH) is mostly associated with head trauma. Non-traumatic subarachnoid hemorrhage is mostly due to vascular abnormalities: either hemorrhage from ruptured aneurysm or bleeding from arteriovenous malformation. Aneurysmal hemorrhage is the biggest cause in non-traumatic cases. Warfarin is associated with cerebral intraparenchymal hemorrhage, but it is rarely associated with SAH.

Case presentation

Here, we report the case of a 45-year-old male patient who was admitted to the neurology ward of our hospital due to acute ischemic stroke. The patient was treated with a vitamin K antagonist (warfarin). However, on the third day, his condition deteriorated (his GCS regressed from 11/15 to 5/15). His pupils were anisocoric. Brain CT showed extensive subarachnoid hemorrhage without intraparenchymal involvement. Cerebral magnetic resonance angiography ruled out aneurysmal rupture. The patient was intubated and transferred to the intensive care unit. Due to his poor condition, neurosurgical intervention could not be done. The patient was managed conservatively, but the patient passed away 4 days later in the intensive care unit.

Clinical discussion

Non-traumatic SAH is mostly caused by aneurysmal rupture. Warfarin increases the risk of intracranial hemorrhage and mostly causes intraparenchymal hemorrhage. Isolated warfarin-related SAH without parenchymal involvement is a rare event. Here we present a young male patient with an isolated warfarin-induced SAH.

Conclusion

Warfarin is rarely associated with isolated subarachnoid hemorrhage. This case highlights a young male patient with spontaneous SAH after warfarin therapy for acute ischemic stroke. Aneurysmal rupture and trauma should be excluded before a diagnosis of warfarin-induced SAH is made.

Dural Venous Sinus Variations in Idiopathic Subarachnoid Hemorrhage: A New Indicator of the Venous Origin with Diagnostic Usefulness?

OBJECTIVE

Venous hypertension associated with a primitive basal vein of Rosenthal (BVR) has been noted as the most likely cause of idiopathic subarachnoid hemorrhage (iSAH). Other types of venous drainage variations have been scarcely studied but may further explain the cases not associated with a BVR anomaly. Our aim was to investigate if dural venous sinus (DVS) anomalies are related with iSAH.

METHODS

A total of 76 patients diagnosed with iSAH were identified from a prospectively maintained database and their angiographic findings compared with 76 patients diagnosed with aneurysmal subarachnoid hemorrhage.

RESULTS

On top of the BVR variations, our data showed a higher prevalence of transverse sinus hypoplasia (47.4% vs. 28.9%; P = 0.019), superior petrosal sinus hypoplasia (32.9% vs. 13.2%; P = 0.003), and clival plexus hyperplasia (65.8% vs. 43.4%; P = 0.005) in patients with iSAH. Analyzing by total number of angiograms, the iSAH group showed also a higher prevalence of inferior petrosal sinus hyperplasia (36.2% vs. 25%; P = 0.003). Of the patients with iSAH without a primitive BVR, 84% harbored ≥1 perimesencephalic DVS variation and the overall number of venous drainage variations was significantly higher in patients with iSAH.

CONCLUSIONS

In addition to the well-documented BVR anomalies, there seems to be a significant relationship of other DVS variations in patients with iSAH. Transverse sinus hypoplasia, superior petrosal sinus hypoplasia, inferior petrosal sinus hyperplasia, and clival plexus hyperplasia were significantly more frequent in patients with iSAH. The presence of ≥3 of those variations would increase the suspicion of a nonaneurysmatic subarachnoid hemorrhage and could help avoid a second angiogram.

Low-Pressure Hydrocephalus in Spontaneous Angiogram-Negative Subarachnoid Hemorrhage Following COVID-19 Infection

A preliminary report warned that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could have neuro-invasive potential as it was observed that some patients showed neurologic symptoms such as headache, nausea, and vomiting. Following early speculation there have been reports of neurologic manifestations involving both the central nervous system and peripheral nervous system including reports that coronavirus disease 2019 (COVID-19) may increase the risk of acute ischemic stroke. Here we present a patient with recent COVID-19 infection who experienced low-pressure hydrocephalus requiring high-output cerebrospinal fluid (CSF) diversion following spontaneous angiogram-negative subarachnoid hemorrhage. We hypothesize that patients who are either currently or who have recently been infected with SARS-CoV-2 may have altered ventricular compliance and/or altered CSF hydrodynamics from mechanisms that are not yet understood but potentially related to previously described pathophysiologic mechanisms of the virus and associated inflammatory reaction.

A Model for Prediction of In-Hospital Mortality in Patients with Subarachnoid Hemorrhage

BACKGROUND

Despite being a rare cause of stroke, spontaneous subarachnoid hemorrhage (SAH) is associated with high mortality rates. The prediction models that are currently being used on SAH patients are heterogeneous, and few address premature mortality. The aim of this study was to develop a mortality risk stratification score for SAH.

METHODS

A retrospective study was carried out with 536 patients diagnosed with SAH who had been admitted to the intensive care unit (ICU) at the University Hospital Complex of A Coruña (Spain) between 2003 and 2013. A multivariate logistic regression model was developed to predict the likelihood of in-hospital mortality, adjusting it exclusively for variables present on admission. A predictive equation of in-hospital mortality was then computed based on the model's coefficients, along with a points-based risk-scoring system. Its discrimination ability was also tested based on the area under the receiver operating characteristics curve and compared with previously developed scores.

RESULTS

The mean age of the patients included in this study was 56.9 ± 14.1 years. Most of these patients (73.9%) had been diagnosed with aneurysmal SAH. Their median length of stay was 7 days in the ICU and 20 days in the general hospital ward, with an overall in-hospital mortality rate of 28.5%. The developed scales included the following admission variables independently associated with in-hospital mortality: coma at onset [odds ratio (OR) = 1.87; p = 0.028], Fisher scale score of 3-4 (OR = 2.27; p = 0.032), Acute Physiology and Chronic Health Evaluation II (APACHE II) score within the first 24 h (OR = 1.10; p < 0.001), and total Sequential Organ Failure Assessment (SOFA) score on day 0 (OR = 1.19; p = 0.004). Our predictive equation demonstrated better discrimination [area under the curve (AUC) = 0.835] (bootstrap-corrected AUC = 0.831) and calibration properties than those of the HAIR scale (AUC = 0.771; p ≤ 0.001) and the Functional Recovery Expected after Subarachnoid Hemorrhage scale (AUC = 0.814; p = 0.154).

CONCLUSIONS

In addition to the conventional risk factors for in-hospital mortality, in our study, mortality was associated with the presence of coma at onset of the condition, the physiological variables assessed by means of the APACHE II scale within the first 24 h, and the total SOFA score on day 0. A simple prediction model of mortality was developed with novel parameters assessed on admission, which also assessed organ failure and did not require a previous etiological diagnosis.

A comparison of frailty indices in predicting length of inpatient stay and discharge destination following angiogram-negative subarachnoid hemorrhage

BACKGROUND AND PURPOSE

While patients with angiogram-negative subarachnoid hemorrhages (ANSAH) have better prognoses than those with aneurysmal SAH, frailty's impact on outcomes in ANSAH is unclear. We previously showed that the modified frailty index (mFI-11) is associated with poor outcomes following ANSAH. Here, we compared the mFI-5, mFI-11, Charlson Comorbidity Index (CCI), and temporalis thickness (TMT) to determine which index was the best predictor of ANSAH outcomes and mortality rates.

METHODS

In this retrospective cohort analysis between 2014 and 2018, patients with non-traumatic, angiogram negative SAH (ANSAH) were identified. The admission mFI-5, mFI-11, CCI, and TMT were calculated for each patient. Primary outcomes were mortality rate, discharge location, and prolonged length of stay (PLOS; LOS >85^th percentile). Multivariate logistic regression and receiver operating characteristic (ROC) curves were used to evaluate frailty as predictors of primary endpoints.

RESULTS

We included 75 patients with a mean age of 55.4 ± 1.5 years. There were 4 patient deaths (5.3%), 53 patients (70.7%) discharged home, and 11 patients (14.7%) with PLOS. On ROC analysis, the mFI-5 had the highest discriminatory value for mortality (AUC = 0.97) while the mFI-11 was most discriminatory for discharge home (AUC = 0.85) and PLOS (AUC = 0.78). On multivariate analysis, the only independent predictor of mortality was the mFI-11 (OR = 0.46; 95%CI: 1.45-14.23; p = 0.009) while the mFI-5 was the best predictor of discharge home (OR = 0.21; 95% CI: 0.08-0.61; p = 0.004). On multivariate analysis, the only independent predictor of PLOS was the Hunt and Hess score (OR = 2.63; 95%CI: 1.38-5.00; p = 0.003). The CCI and TMT were inferior to either mFI for predicting primary endpoints.

CONCLUSIONS

Increasing frailty is associated with poorer outcomes and higher mortality following ANSAH. The mFI-5 and mFI-11 were found to be superior predictors of discharge home and mortality rate. While larger prospective study is needed, frailty, as measured by mFI-11 and -5, should be considered when evaluating ANSAH prognosis.

Variability of Clinical and Angiographic Results Based on the Treatment Preference (Endovascular or Surgical) of Centers Participating in the Subarachnoid Hemorrhage Database of the Working Group of the Spanish Society of Neurosurgery

OBJECTIVES

Since the introduction of endovascular treatment for cerebral aneurysms, hospitals in which subarachnoid hemorrhage is treated show different availability and/or preferences towards both treatment modalities. The main aim is to evaluate the clinical and angiographic results according to the hospital's treatment preferences applied.

METHODS

This study was conducted based on use of the subarachnoid hemorrhage database of the Vascular Pathology Group of the Spanish Neurosurgery Society. Centers were classified into 3 subtypes according to an index in the relationship between endovascular and surgical treatment as: endovascular preference, high endovascular preference, and elevated surgical preference. The clinical results and angiographic results were evaluated among the 3 treatment strategies.

RESULTS

From November 2004 to December 2017, 4282 subarachnoid hemorrhage patients were selected for the study: 630 (14.7%) patients from centers with surgical preference, 2766 (64.6%) from centers with endovascular preference, and 886 (20.7%) from centers with high endovascular preference. The surgical preference group obtained the best angiographic results associated with a greater complete exclusion (odds ratio: 1.359; 95% confidence interval: 1.025-1.801; P = 0.033). The surgical preference subgroup obtained the best outcome at discharge (65.45%), followed by the high endovascular preference group (61.5%) and the endovascular preference group (57.8%) (odds ratio: 1.359; 95% confidence interval: 1.025-1.801; P = 0.033).

CONCLUSIONS

In Spain, there is significant variability in aneurysm exclusion treatment in aneurysmal subarachnoid hemorrhage. Surgical centers offer better results for both surgical and endovascular patients. A multidisciplinary approach and the maintenance of an elevated quality of surgical competence could be responsible for these results.

Increasing Frailty Predicts Worse Outcomes and Increased Complications After Angiogram-Negative Subarachnoid Hemorrhages

BACKGROUND

The effect of frailty on outcomes after angiogram-negative subarachnoid hemorrhages (ANSAH) is currently unknown. We investigated frailty's effects on ANSAH outcomes, including mortality and in-hospital complications.

METHODS

Patients from 2014 to 2018 with non-traumatic subarachnoid hemorrhage and cerebral angiograms with an unidentifiable hemorrhage source were retrospectively reviewed. The cohort was divided into non-frail (modified frailty index [mFI] = 0) and frail (mFI ≥1) groups based on pre-hemorrhage characteristics. Primary outcomes were mortality rate and discharge location. Multivariate logistic regression analyses determined predictors of ANSAH severity and primary endpoints. Receiver operating characteristic curves were used to discriminate risks for primary endpoints comparing mFI, Hunt and Hess and Fisher scores, and age.

RESULTS

We included 75 patients with a mean age of 55.4 ± 1.5 years, comprising 42 (56%) women, and 41 (54.7%) with perimesencephalic bleeds. A total of 32 of 75 (42.7%) patients were classified as frail. Frail individuals were 6.2 times less likely to be discharged home (odds ratio [OR] = 0.16; 95% confidence interval [CI]: 0.05-0.5; P = 0.001) and all mortalities occurred in frail patients (12.5% [n = 4 of 32]; P = 0.030). The only independent predictor of mortality was higher mFI (OR = 5.4; 95% CI: 1.5-19.1; P = 0.009), and lower mFI best predicted discharge home (OR = 0.39; 95% CI: 0.17-0.88; P = 0.023). Receiver operating characteristic analysis showed that mFI best predicted both mortality (area under the curve = 0.9718; P = 0.002) and discharge home (area under the curve = 0.7998; P < 0.001).

CONCLUSIONS

Frail ANSAH patients have poorer outcomes and increased mortality compared with non-frail patients. Although prospective study is needed, this information significantly impacts our understanding of ANSAH outcomes and frailty should be used for prognostication as it was a better predictor than Hunt and Hess or Fisher scores.

Characteristics of Unruptured Compared to Ruptured Intracranial Aneurysms: A Multicenter Case-Control Study

BACKGROUND

Only a minority of intracranial aneurysms rupture to cause subarachnoid hemorrhage.

OBJECTIVE

To test the hypothesis that unruptured aneurysms have different characteristics and risk factor profiles compared to ruptured aneurysms.

METHODS

We recruited patients with unruptured aneurysms or aneurysmal subarachnoid hemorrhages at 22 UK hospitals between 2011 and 2014. Demographic, clinical, and imaging data were collected using standardized case report forms. We compared risk factors using multivariable logistic regression.

RESULTS

A total of 2334 patients (1729 with aneurysmal subarachnoid hemorrhage, 605 with unruptured aneurysms) were included (mean age 54.22 yr). In multivariable analyses, the following variables were independently associated with rupture status: black ethnicity (odds ratio [OR] 2.42; 95% confidence interval [CI] 1.29-4.56, compared to white) and aneurysm location (anterior cerebral artery/anterior communicating artery [OR 3.21; 95% CI 2.34-4.40], posterior communicating artery [OR 3.92; 95% CI 2.67-5.74], or posterior circulation [OR 3.12; 95% CI 2.08-4.70], compared to middle cerebral artery). The following variables were inversely associated with rupture status: antihypertensive medication (OR 0.65; 95% CI 0.49-0.84), hypercholesterolemia (0.64 OR; 95% CI 0.48-0.85), aspirin use (OR 0.28; 95% CI 0.20-0.40), internal carotid artery location (OR 0.53; 95% CI 0.38-0.75), and aneurysm size (per mm increase; OR 0.76; 95% CI 0.69-0.84).

CONCLUSION

We show substantial differences in patient and aneurysm characteristics between ruptured and unruptured aneurysms. These findings support the hypothesis that different pathological mechanisms are involved in the formation of ruptured aneurysms and incidentally detected unruptured aneurysms. The potential protective effect of aspirin might justify randomized prevention trials in patients with unruptured aneurysms.

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.

Spontaneous Subarachnoid Haemorrhage in Neurological Setting in Burkina Faso: Clinical Profile, Causes, and Mortality Risk Factors

To determine the prevalence, clinical profile, causes, and mortality risk factors of spontaneous arachnoid haemorrhage at Yalgado Ouedraogo University teaching Hospital, we conducted a 5-year retrospective study of 1803 stroke patients admitted to Neurology Department during the period from January 2012 to December 2016. During the study period, spontaneous subarachnoid haemorrhage accounted for 3.2 % of all stroke. The mean age of patients was 60 years (range 20-93 years). There was a female predominance in 55.9%. The common vascular risk factors were hypertension (79.7%) and chronic alcohol consumption (16.9%). The main symptoms were headache (76.2%), motor weakness (74.5%), and consciousness disorders (62.7%). Neurological examination revealed limb weakness in 76.2% and meningeal irritation in 47.4%. The best admission Glasgow Coma Scale score of 15 was found only in 37.3 % of patients. About 50.8% of patients were admitted to Hunt and Hess moderate grade (III) resulting in a mortality of 24.80%. The main cause of spontaneous subarachnoid haemorrhage was hypertension (77.9%). Cause could not be determined in 8.5 % of cases. The mortality rate was 37.3%. There was high mortality in patients with intraventricular haemorrhage and in patients with disturbances of consciousness. In conclusion, our study showed a poor frequency of spontaneous subarachnoid haemorrhage with high mortality. Hypertension was the most common cause of spontaneous subarachnoid haemorrhage.

Low-chloride versus high-chloride hypertonic solution for the treatment of subarachnoid hemorrhage-related complications (The ACETatE trial): study protocol for a pilot randomized controlled trial

Background

Aneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening condition that results from a ruptured cerebral vessel. Cerebral edema and vasospasm are common complications and frequently require treatment with hypertonic solutions, in particular hypertonic sodium chloride (NaCl). We have previously shown that hyperchloremia in patients with aSAH given hypertonic NaCl is associated with the development of acute kidney injury (AKI), which leads to higher morbidity and mortality. Our current trial aims to study the effect of two hypertonic solutions with different chloride content on serum chloride concentrations in patients with aSAH who are at risk for AKI.

Methods

A low ChloridE hyperTonic solution for brain Edema (ACETatE) is a single center, double-blinded, double-dummy pilot trial comparing bolus doses of 23.4% NaCl and 16.4% NaCl/Na-Acetate for the treatment of cerebral edema in patients with aSAH. All patients will be enrolled within 36 h following admission. Randomization will occur once patients who receive hypertonic treatment for cerebral edema develop hyperchloremia (serum Cl⁻ concentration ≥ 109 mmol/L). Subsequent treatment will consist of either NaCl 23.4% or NaCl/Na-Acetate 16.4%. The primary outcome of this study will be the change in serum Cl⁻ concentrations during treatment. Secondary outcomes will include incidence of AKI, mortality, changes in intracranial pressure, and extent of hypernatremia.

Discussion

In patients with aSAH, hyperchloremia is a known risk factor for subsequent development of AKI. The primary goal of this pilot study is to determine the effect of two hypertonic solutions with different Cl⁻ content on serum Cl⁻ concentrations in patients with aSAH who have already developed hyperchloremia. Data will be collected prospectively to determine the extent to which the choice of hypertonic saline solution affects subsequent serum Cl⁻ concentrations and the occurrence of AKI. This approach will allow us to obtain preliminary data to design a large randomized trial assessing the effects of chloride-sparing hypertonic solutions on development of AKI in patients with SAH. This pilot study is the first to prospectively evaluate the relationship between hypertonic solution chloride content and its effect on serum electrolytes and renal function in aSAH patients at risk of AKI due to hyperchloremia.

Trial registration

Clinicaltrials.gov, NCT03204955. Registered on 28 June 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-3007-7) contains supplementary material, which is available to authorized users.

The Incidence of Hydrocephalus and Shunting in Patients with Angiogram-Negative Subarachnoid Hemorrhage: An Updated Meta-Analysis

OBJECTIVE

To evaluate the incidence of hydrocephalus and implanted shunts in angiogram-negative subarachnoid hemorrhage (SAH) according to hemorrhage patterns: perimesencephalic SAH (PMH) versus non-PMH.

METHODS

The online database literature from January 1990 to November 2017 was systematically reviewed. A fixed-effect model was used when heterogeneity was <50%. A Begg funnel plot was used to assess publication bias. An additional trim and fill method was used to estimate the number of missing studies. A subgroup analysis with studies, which defined angiogram-negative SAH using repeated angiography or computed tomography angiography, was further performed.

RESULTS

A total of 28 articles including 2577 patients were enrolled. Patients with PMH showed a significantly decreased incidence of hydrocephalus (odds ratio [OR], 0.269; 95% confidence interval [CI], 0.208-0.348) and shunts (OR, 0.263; 95% CI, 0.169-0.411) than did patients without PMH. A subgroup analysis of 7 studies with 675 patients showed less hydrocephalus in patients with PMH than in patients without PMH (OR, 0.358; 95% CI, 0.161-0.793), with possible publication bias. Shunt procedures were marginally less common in patients with PMH compared with those patients without PMH (OR, 0.490; 95% CI, 0.236-1.018) with possible publication bias. After correction of the forest plot, the adjusted OR was 0.617 (95% CI, 0.251-1.513) for hydrocephalus and 0.618 (95% CI, 0.310-1.232) for shunts, suggesting no significant relationships between PMH and the risk of hydrocephalus or shunting.

CONCLUSIONS

Hydrocephalus and shunts were more evident in non-PMH than PMH. However, subgroup analyses did not show significant associations between PMH and lower risks of these events after correction for possible publication bias. Further meta-analyses based on individual patient data are necessary.

Midterm Follow-Up of 20 Consecutive Patients with Nonaneurysmal Subarachnoid Hemorrhage of Unknown Origin in a Single-Center: Two Cases of De Novo Development of Dural Arteriovenous Fistula

BACKGROUND AND PURPOSE

The mechanisms and prognosis of underlying subarachnoid hemorrhage of unknown origin remain unclear. Previous investigators have suggested a relationship between nonaneurysmal perimesencephalic subarachnoid hemorrhage and venous abnormalities like a primitive venous drainage of the basal vein of Rosenthal. We report the outcome of a midterm follow-up of 20 consecutive patients with nonaneurysmal subarachnoid hemorrhage of unknown origin, and 2 patients in whom the development of new dural arteriovenous fistulas after subarachnoid hemorrhage of unknown origin were detected during follow-up.

METHODS

All patients who were admitted to our hospital for nontraumatic subarachnoid hemorrhage between April 2008 and March 2016 were retrospectively analyzed.

RESULTS

Of 705 patients included in the study, 20 (2.8%) were diagnosed with nontraumatic subarachnoid hemorrhage of unknown origin. During the follow-up periods, there was no rebleeding. Although 18 patients did not show any vascular abnormalities, the other 2 patients were diagnosed with dural arteriovenous fistula. Both fistulas were successfully treated with endovascular embolization.

CONCLUSIONS

Subarachnoid hemorrhage of unknown origin had a low incidence rate, and its clinical course was excellent without rebleeding. Although no vascular abnormalities were observed during the patients' initial admission, venous lesions might have been involved in both subarachnoid hemorrhages and delayed dural arteriovenous fistulas. Here, the possible pathogenesis is discussed with a review of the literature.

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 spontaneous subarachnoid hemorrhage: perimesencephalic versus non-perimesencephalic

Objective

To compare the clinical evolution of perimesencephalic subarachnoid hemorrhage and non-perimesencephalic subarachnoid hemorrhage.

Methods

The study was conducted retrospectively in a tertiary hospital center in the north region of Portugal. Included patients had no identifiable cause for subarachnoid hemorrhage. Several epidemiologic, clinical and imaging aspects were statistically analyzed, taking into account the differences in perimesencephalic subarachnoid hemorrhage and non-perimesencephalic subarachnoid hemorrhage.

Results

Sixty-two patients met the inclusion criteria (46.8% - perimesencephalic subarachnoid hemorrhage; 53.2% - non-perimesencephalic subarachnoid hemorrhage). Demographic and clinical background characteristics were similar in both groups. Complications were more frequent in patients with non-perimesencephalic subarachnoid hemorrhage - 84.8% of the patients had at least one complication versus 48.3% in perimesencephalic subarachnoid hemorrhage. Vasospasm, infection and hydrocephaly were the most common complications (each was detected more frequently in the non-perimesencephalic subarachnoid hemorrhage group than in perimesencephalic subarachnoid hemorrhage group). Two patients died, both had a non-perimesencephalic subarachnoid hemorrhage. The median inpatient time was longer in the non-perimesencephalic subarachnoid hemorrhage group (21 versus 14 days). No incidents of rebleeding were reported during the follow-up period (mean time of 15 ± 10.3 months).

Conclusion

Perimesencephalic subarachnoid hemorrhage and non-perimesencephalic subarachnoid hemorrhage are two different entities that have different clinical outcomes, namely in terms of complication rate and median inpatient time. The management of these patients should respect this difference to improve treatment and optimize health care resources.

Short- and long-term outcomes in non-aneurysmal non-perimesencephalic subarachnoid hemorrhage

OBJECTIVE

Our aim was to assess the short- and long-term prognosis in patients suffering from non-aneurysmal non-perimesencephalic SAH (Na-NPM-SAH).

METHODS

Based on admission CT-scan, SAH was categorized as perimesencephalic (PM) or non-perimesencephalic (NPM). Based on digital subtraction angiography (DSA) results, patients were classified as normal DSA (Na-SAH) or aneurysmal SAH (aSAH). Between 1997 and 2010, 67 of 571 patients with non-traumatic SAH (11.7%) suffered from non-aneurysmal non-perimesencephalic SAH. Retrospective analyses of the 67 patients were undertaken, and compared with the aneurysmal SAH group. Long-term follow-up was assessed.

RESULTS

The cohort consisted of 67 Na-NPM-SAH patients, mean age 54.8 years (range: 21-84), 56.7% male. Acute phase: 10.4% mortality and 3% rebleeding (two patients) during the acute phase. Long-term: extensive follow-up was possible in all except one of the survivors at discharge. Mortality was 6.6% during the 510 patient-years follow-up period (median follow-up time per patient, 8.95 years); rebleeding rate was 0-1.6%. An aneurysmal source was found in 13% of patients who underwent a second angiography. Aneurysmal SAH: 312 patients, with confirmed aneurysm by angiography. The mortality rate for Na-NPM-SAH during the acute phase was 10.4%, vs. 20% for aneurysmal SAH in the general database, p = 0.049.

DISCUSSION

Na-NPM-SAH patients without an identifiable bleeding source on initial angiography might have a more benign short- and long-term prognosis than aneurysmal SAH patients. Our study confirms an important diagnostic advantage of a second arteriography. Still, despite the major concern of an undetected aneurysm, the long-term rebleeding rate was low in this subgroup of patients.

Perimesencephalic subarachnoid hemorrhage with a positive angiographic finding: case report and review of the literature

The vast majority of perimesencephalic subarachnoid hemorrhage cases are reported as negative-finding etiologies. Recently, high-resolution images allowed us to overcome the previous difficulty of finding the source of bleeding, which underlies the concept of a "negative finding". We discovered a venous etiology, hidden behind the tip of the basilar artery; namely, the lateral pontine vein. Here, we review the literature on perimesencephalic subarachnoid hemorrhage and on venous aneurysm. We highlight this type of aneurysm as a candidate source of perimesencephalic hemorrhage. This case may change our way of dealing with what we have termed a negative finding of subarachnoid hemorrhage.

Use of Follow-Up Imaging in Isolated Perimesencephalic Subarachnoid Hemorrhage

Background and Purpose—

Multiple studies have shown that negative computed tomographic angiograms (CTAs) are reliable in excluding aneurysms in patients with isolated perimesencephalic subarachnoid hemorrhage (pSAH). We evaluate the use of digital subtraction angiography versus CTA for initial diagnosis and of angiographic follow-ups in patients with pSAH by performing an institutional analysis and a meta-analysis of literature.

Methods—

Retrospective institutional analysis of patients with pSAH was performed from 2008 to 2014. The number and types of follow-up imaging studies were tabulated. Initial and follow-up studies were evaluated by an experienced neuroradiologist for intracranial aneurysm. Meta-analysis of literature was performed to assess the use of initial digital subtraction angiography and of follow-up imaging.

Results—

Our institutional review revealed no additional use of initial digital subtraction angiography or of any angiographic follow-up after initial negative CTA in patients with pSAH on noncontrast CT. Meta-analysis of 40 studies yielded a total of 1031 patients. Only 8 aneurysms were first diagnosed on follow-ups (0.78%). Careful review showed that some of these aneurysms reported on follow-up are of questionable validity. Initial digital subtraction angiography and follow-up imaging after a negative initial CTA showed no statistically significant benefits.

Conclusions—

In patients meeting the strict imaging criteria of pSAH, initial negative CTA is reliable in excluding aneurysms. A critical review of the literature through meta-analysis shows no foundation for multiple follow-up studies in patients with pSAH.

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.

Differences in the Basilar Artery Bifurcation Angle Among Patients Who Present With a Ruptured Aneurysm at the Top of the Basilar Artery and Patients With Perimesencephalic Subarachnoid Hemorrhage

BACKGROUND:

The angle of the basilar artery bifurcation of (BAB angle) is thought to influence the risk of the development and rupture of aneurysms at this site. It is, however, unknown whether the BAB angle also influences the incidence of angiographically negative perimesencephalic subarachnoid hemorrhage (PMSAH).

OBJECTIVE:

We performed a retrospective cross-sectional study comparing the BAB angle in a series of patients who presented with subarachnoid hemorrhage from a ruptured aneurysm at the top of the basilar artery (BSAH) with the BAB angle in a series of patients who presented with PMSAH.

METHODS:

Consecutive patients who presented to our institution with PMSAH or BSAH between January 1, 2005 and December 31, 2010 were studied. Patients with PMSAH were further subdivided into patients with classic PMSAH (CPMSAH) and those with nonclassic PMSAH (NCPMSAH) based on initial head computed tomography examinations. In each patient, the BAB angle was measured on the standard cranial anteroposterior projections after vertebral artery injections.

RESULTS:

A total of 21 patients with CPMSAH, 30 patients with NCPMSAH, and 31 patients with BSAH were studied. The BAB angle was significantly smaller in patients with CPMSAH (87.7 ± 17.1 degrees) and NCPMSAH (98.4 ± 21.1 degrees) compared with patients with BSAH (135.0 ± 30.8 degrees) (P &lt; .001).

CONCLUSION:

The significantly lower BAB angle in PMSAH patients compared with BSAH patients suggests that bleeding in PMSAH is either nonarterial in nature or is secondary to variations in hemodynamic arterial stress at the top of the basilar artery that need to be studied further with computational models.

Cerebral arterial fenestrations: a common phenomenon in unexplained subarachnoid haemorrhage

BACKGROUND

Fenestrations of intracranial arteries are variants resulting from incomplete fusion of vessels during development with unknown clinical significance. They are best visualised with 3D rotational angiography (3DRA).

OBJECTIVE

In a prospective consecutive series of patients with suspected aneurysms, 3DRA was performed to identify not only the potential bleeding source but also to assess the frequency and location of any fenestrations of intracranial arteries.

METHODS

In 287 consecutive patients with possible intracranial aneurysms (accidental discovery or previous history of SAH), 3DRAs were prospectively performed, and the location of subarachnoid haemorrhage was assessed by CT.

RESULTS

Of 174 patients presenting with SAH, 153 had saccular aneurysms, and in 21 cases (12.1 %), no source of bleeding was found. In 20 of these 21 patients with "unexplained SAH" (95.2 %) an arterial fenestration was detected in the neighbourhood of the clot. The incidence of fenestration in the 153 aneurysmal SAH patients was 22.9 %, and it was 23.3 % in 266 patients with intracranial aneurysms (113 accidental and 153 ruptured).

CONCLUSIONS

Arterial fenestration was detected in 22.9 % of ruptured cerebral aneurysms, in contrast with 95.2 % in patients with unexplained SAH, the difference being statisctically significant (p < 0.01). Fenestration is a developmental defect, a structural wall weakness possibly making the vessel prone to rupture. Its incidence of nearly 100 % may suggest a connection with idiopathic SAH. The presented data indicate that arterial fenestrations are generally overlooked, and they can be considered as one of the candidates for the source of idiopathic SAH.

Nonaneurysmal subarachnoid hemorrhage: an update

Nonaneurysmal subarachnoid hemorrhage (NA-SAH) constitutes a heterogeneous group of patients, both perimesencephalic (PMN-SAH) and non-perimesencephalic (nPMN-SAH). Despite many reports and case series, the etiology of NA-SAH remains uncertain. The differences in clinical course and outcome between PMN-SAH and nPMN-SAH are evident and have to be taken into consideration at the time of admission, as aggressive diagnostic evaluation and management are required for latter patient. In terms of diagnostic evaluation, the most important determination is to differentiate PMN-SAH from nPMN-SAH and aneurysmal SAH. PMN-SAH can be distinguished on CT in the majority of patients, but should be confirmed by a negative cerebral angiography. In addition, Convexal NA-SAH is another important subtype of NA-SAH associated with diverse etiologies and symptoms, although prognosis is generally favorable.

Clinical management guidelines for subarachnoid haemorrhage. Diagnosis and treatment

OBJECTIVE

To update the Spanish Society of Neurology's guidelines for subarachnoid haemorrhage diagnosis and treatment.

MATERIAL AND METHODS

A review and analysis of the existing literature. Recommendations are given based on the level of evidence for each study reviewed.

RESULTS

The most common cause of spontaneous subarachnoid haemorrhage (SAH) is cerebral aneurysm rupture. Its estimated incidence in Spain is 9/100 000 inhabitants/year with a relative frequency of approximately 5% of all strokes. Hypertension and smoking are the main risk factors. Stroke patients require treatment in a specialised centre. Admission to a stroke unit should be considered for SAH patients whose initial clinical condition is good (Grades I or II on the Hunt and Hess scale). We recommend early exclusion of aneurysms from the circulation. The diagnostic study of choice for SAH is brain CT (computed tomography) without contrast. If the test is negative and SAH is still suspected, a lumbar puncture should then be performed. The diagnostic tests recommended in order to determine the source of the haemorrhage are MRI (magnetic resonance imaging) and angiography. Doppler ultrasonography studies are very useful for diagnosing and monitoring vasospasm. Nimodipine is recommended for preventing delayed cerebral ischaemia. Blood pressure treatment and neurovascular intervention may be considered in treating refractory vasospasm.

CONCLUSIONS

SAH is a severe and complex disease which must be managed in specialised centres by professionals with ample experience in relevant diagnostic and therapeutic processes.