Subarachnoid Hemorrhage Of Unknown Origin Research Articles

Systemic Inflammatory Response in Spontaneous Subarachnoid Hemorrhage from Aneurysmal Rupture versus Subarachnoid Hemorrhage of Unknown Origin.

It is well known that spontaneous non-aneurysmal subarachnoid hemorrhage (SAH), also known as sine materia SAH (smSAH), has usually a better course and prognosis than its aneurysmal counterpart (aSAH). This might depend on different inflammatory mechanisms initiated by bleeding events of different origins. The aim of the present study was to explore the systemic inflammatory response in spontaneous SAH, comparing aSAH and smSAH. We performed a prospective observational study over a consecutive series of patients with SAH. For these patients, we collected all clinical data and, furthermore, performed venous blood sampling over six time points to analyze blood cells. We further performed the analysis of lymphocytes and monocytes by means of flow cytometry to quantify common subtypes. Statistical analysis included a t-student test, Chi-square test, multivariate logistic regression, and ROC analysis. 48 patients were included: six (12.5%) with a diagnosis of spontaneous smSAH, and forty-two patients (87.5%) with aSAH. Significant differences on Day 0 were found for neutrophils and a systemic neuro-inflammatory index, namely, systemic inflammatory response index (SIRI). At the ROC analysis, neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), and SIRI exhibited satisfactory predictive power on day 0. At the multivariable logistic regression analysis, the combined index (NLR, LMR, SIRI at day 0) yielded an OR of 0.59 (95% CI 0.29-1.21]). LMR at day 0 yielded an OR of 1.25 ([95% CI 0.94-1.68]), NLR at day 0 exhibited an OR of 0.68 ([95% CI 0.42-1.09]), and SIRI at day 0 displayed an OR of 0.31 ([95% CI 0.06-1.49]). This preliminary study indicated a possible role of some inflammatory indices that point out the importance of innate and adaptive immunity in the etiopathogenetic mechanisms. Drugs modulating these responses could eventually counteract or, at least, reduce secondary damage associated with SAH.

Subarachnoid Hemorrhage of Unknown Origin at Initial Imaging Investigation

In some patients with spontaneous subarachnoid hemorrhage(SAH), initial imaging investigations may not be able to detect a bleeding source;repeat imaging may be necessary to reveal these lesions. We reviewed a consecutive series of 45 patients with SAH and negative initial digital subtraction angiograms(DSA)during a 15-year period. The aims were to document the frequency and reason for the negative initial investigations, to determine the appropriate modality and timing of repeat examinations, and to investigate the identified bleeding sources. Twenty-eight(62%)patients underwent repeat DSA, 35(78%)underwent magnetic resonance imaging(MRI), and 33(73%)underwent computed tomography angiography(CTA). Nine lesions(5 small aneurysms, 2 craniocervical junction arteriovenous fistulas, 1 arteriovenous malformation, and 1 internal carotid artery dissection)were identified on subsequent DSA after 2-3 weeks. Most aneurysms were identified on an atypical vascular tree. CTA or MRI alone were unable to disclose the culprit lesions. In retrospect, human errors including oversight were the major reasons for the negative initial investigation results. It is, however, difficult to search for a tiny vascular lesion that might be anywhere in the cranium. Repeat DSA is still the gold standard for the inspection of hidden bleeding sources in patients with SAH of unknown origin.

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

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

Spontaneous subarachnoid hemorrhage of unknown origin: hospital course and long-term clinical and angiographic follow-up.

Hemorrhagic origin is unidentifiable in 10%-20% of patients presenting with spontaneous subarachnoid hemorrhage (SAH). While the patients in such cases do well clinically, there is a lack of long-term angiographic followup. The authors of the present study evaluated the long-term clinical and angiographic follow-up of a patient cohort with SAH of unknown origin that had been enrolled in the Barrow Ruptured Aneurysm Trial (BRAT). The BRAT database was searched for patients with SAH of unknown origin despite having undergone two or more angiographic studies as well as MRI of the brain and cervical spine. Follow-up was available at 6 months and 1 and 3 years after treatment. Analysis included demographic details, clinical outcome (Glasgow Outcome Scale, modified Rankin Scale [mRS]), and repeat vascular imaging. Subarachnoid hemorrhage of unknown etiology was identified in 57 (11.9%) of the 472 patients enrolled in the BRAT study between March 2003 and January 2007. The mean age for this group was 51 years, and 40 members (70%) of the group were female. Sixteen of 56 patients (28.6%) required placement of an external ventricular drain for hydrocephalus, and 4 of these subsequently required a ventriculoperitoneal shunt. Delayed cerebral ischemia occurred in 4 patients (7%), leading to stroke in one of them. There were no rebleeding events. Eleven patients were lost to followup, and one patient died of unrelated causes. At the 3-year follow-up, 4 (9.1%) of 44 patients had a poor outcome (mRS > 2), and neurovascular imaging, which was available in 33 patients, was negative. Hydrocephalus and delayed cerebral ischemia, while infrequent, do occur in SAH of unknown origin. Long-term neurological outcomes are generally good. A thorough evaluation to rule out an etiology of hemorrhage is necessary; however, imaging beyond 6 weeks from ictus has little utility, and rebleeding is unexpected.

Isolated thrombosis of the vein of Labbe after contralateral cortical subarachnoid hemorrhage of unknown origin with positive antinuclear antibody

We report a rare case of isolated thrombosis of the vein of Labbe after subarachnoid hemorrhage (SAH) of unknown origin on the contralateral side. A 39-year-old man with no known previous medical history suffered from headaches and nausea. Computed tomography showed a mild SAH in the right distal Sylvian fissure. Digital subtraction angiography (DSA) showed no vascular lesion responsible for the SAH. Six days after admission, he suddenly developed generalized seizures. Computed tomography showed a high-density lesion in the left temporal lobe. Magnetic resonance imaging showed the pattern of hemorrhagic infarction. DSA showed a complete filling defect of the left vein of Labbe. Anticoagulation and anticonvulsant treatment were carried out. The clinical course was favorable. After discharge, laboratory examinations showed remarkably increased antinuclear antibody titer (×2560). Although the antiphospholipid syndrome was denied, the high level of antinuclear antibody might have been related to these lesions through an unknown etiology.

Subarachnoid hemorrhage as a psychological trauma

Despite the progress made in the management of subarachnoid hemorrhage (SAH), many patients complain of persistent psychosocial and cognitive problems. The present study was performed to explore the significance of psychological traumatization by the bleeding with respect to psychosocial results after SAH. A series of 45 patients were examined in a cross-sectional study an average of 49.4 months after SAH by means of a quality-of-life questionnaire, the Beck Depression Inventory, the German version of the Impact of Event Scale (IES), and a clinical interview (Structured Clinical Interview for DSM Disorders) to make the diagnosis of chronic posttraumatic stress disorder (PTSD). Twenty-nine patients underwent surgery for treatment of a ruptured aneurysm; the remaining 16 patients had SAH of unknown origin. Twelve patients (27%) exhibited PTSD, and almost two-thirds of the 45 patients in the study reported substantial fear of recurrent hemorrhage. Not only the presence of PTSD but the severity of psychological traumatization as assessed by the IES explained up to 40% of the variance of the self- and proxy-rated impairments. Multivariate analyses revealed psychological traumatization (IES) and neurological state on admission (Hunt and Hess grade) as substantial predictors of the self- and proxy-rated quality of life, explaining 31% and 42% of the variance, respectively. Even several years after SAH, the severity of psychological traumatization by the bleeding substantially determines the degree of psychosocial impairment. In the future, this issue should be addressed in the care of these patients. Furthermore, the development of psychological interventions is called for to prevent the emergence of PTSD after SAH.

Special features of subarachnoid hemorrhage of unknown origin: a review of a series of 179 cases

Objectives: The aim of this study was to work out the special features of subarachnoid hemorrhage (SAH) of unknown origin in respect of diagnostic evaluation, clinical course, and outcome in a large cohort of patients.Methods: We reviewed the data of 179 patients with SAH of unknown origin during 1991 and 2008. The differentiation between perimesencephalic (PM-SAH) and non-perimesencephalic SAH (NON-PM-SAH) was done under consideration of the bleeding pattern on CT scanning.Results: Among 1226 treated patients with spontaneous SAH over a time period of 17 years, a bleeding source remained undetected on first digital subtraction angiogram (DSA) in 179 patients (16·7%) — 47 PM-SAH (26·3%) and 132 NON-PM-SAH (73·7%). The clinical signs of patients with PM-SAH were less marked compared to those with NON-PM-SAH, equally to the Hunt and Hess grade. magnetic resonance imaging (MRI) and MR angiography had 100% negative findings for non-aneurismal bleeding sources in all patients. Second DSA revealed a bleeding source in the NON-PM group in 10·8%. The clinical course of the patients with NON-PM-SAH showed a significantly higher rate of complications and a mortality of about 10%. The outcome was excellent in the PM group, in contrast to a fatal course in 13 cases in the NON-PM group.Discussion: PM-SAH imposed with a mild clinical course and an excellent outcome, without severe complications. In contrast to this, NON-PM-SAH has a significant higher rate of dreaded complications and mortality. It is crucial to make an exact diagnosis of PM-SAH, considering CT scanning during the first 24 hours after occurrence of symptoms and the radiological features.

Anterior Spinal Artery Syndrome in a Patient with Vasospasm Secondary to a Ruptured Cervical Dural Arteriovenous Fistula

Spinal dural arteriovenous fistulas (DAVF) in the cervical spine are known to cause subarachnoid hemorrhage. Vasospasm after rupture of a DAVF, however, has not previously been reported. A 48-year-old woman who presented with the sudden onset of altered mental status. Imaging demonstrated extensive subarachnoid hemorrhage and spinal DAVF at C1 to C2. The patient underwent a suboccipital craniotomy for DAVF ligation. On post-operative day three, she began having acute weakness in all her extremities with proprioception and vibration preserved, whereas pain and temperature sensation was lost. An angiogram demonstrated bilateral vertebral artery vasospasm with no filling of the anterior spinal artery. Bilateral angioplasty of the vertebral arteries was performed successfully and post-angioplasty, the right vertebral artery was filling the anterior spinal artery. The patient clinically improved. She subsequently required treatment with n-butyl cyanoacrylic acid (nBCA) embolization and gamma knife radiosurgery to achieve obliteration of the lesion. For patients with subarachnoid hemorrhage of unknown origin, differential diagnosis should include DAVF. This patient also presented with vasospasm in the context of ruptured DAVF, a complication previously unreported in the literature. This finding suggests that close monitoring for vasospasm after rupture of DAVF is warranted.

Persistent primitive first cervical intersegmental artery (proatlantal artery II) associated with subarachnoid hemorrhage of unknown origin

Proatlantal intersegmental artery is a persistent arotid–vertebral embryonic anastomosis. This artery is very are, and 2 types have been described, proatlantal artery types and II. Persistent primitive proatlantal intersegmental artery proatlantal artery type I) arises from the internal carotid artery nd transverses rostrally to enter the foramen magnum where t joins the vertebral artery. Persistent primitive first cervical ntersegmental artery (proatlantal artery type II) arises from the xternal carotid artery, runs posteriorly to join the vertebral rtery and then passes through the transverse foramen of the C1 ertebra segment. The purpose of this paper is to present a case ith proatlantal artery type II without an ipsilateral vertebral rtery. This anomaly was an incidental finding in a patient with ubarachnoid hemorrhage (SAH) of unknown origin.

Diagnostic value of magnetic resonance imaging in perimesencephalic and nonperimesencephalic subarachnoid hemorrhage of unknown origin

The aim of this study was to evaluate the diagnostic value of MR imaging in perimesencephalic (PM) and nonperimesencephalic (non-PM) subarachnoid hemorrhage (SAH) of unknown origin. The authors conducted a retrospective review of all patients with SAH (1226 patients) in their department between January 1991 and December 2008. Included in the study were cases of spontaneous SAH diagnosed using CT scans obtained within 24 hours of the initial symptoms and initially negative digital subtraction (DS) angiograms. Patients with traumatic SAH and an unknown history were excluded from the study. Patients with initially negative DS angiograms were divided into 2 groups: Group 1, a typically PM bleeding pattern (PM SAH); and Group 2, a non-PM bleeding pattern (non-PM SAH) such as hemorrhage in the sylvian or interhemispheric fissure. Cranial MR imaging including the craniocervical region was performed within 72 hours after SAH was diagnosed in all patients in Groups 1 and 2. One thousand sixty-eight patients underwent DS angiography, and among them were 179 (16.7%) with negative angiograms--47 patients (26.3%) from Group 1 and 132 patients (73.7%) from Group 2. Magnetic resonance imaging demonstrated no bleeding sources in any case (100% negative). Thirty-four patients in Group 1 and 120 patients in Group 2 underwent a second DS angiography study. Digital subtraction angiography revealed an aneurysm as the bleeding source in 1 case in Group 1 and in 13 cases in Group 2. Magnetic resonance imaging of the brain and craniocervical region did not produce additional benefit for the detection of a bleeding source and the therapy administered for PM SAH and non-PM SAH (100% negative). The costs of this examination exceeded the clinical value. Despite the results of this study, MR imaging should be discussed on a case-by-case basis because rare bleeding sources are periodically diagnosed in cases of non-PM SAH. A second-look DS angiogram is necessary because aneurysmal hemorrhage occasionally produces PM SAH as well as non-PM SAH. Further prospective studies are needed to verify the authors' results in the future.

Outcome correlates with blood distribution in subarachnoid hemorrhage of unknown origin

Between 15 and 30 % of patients with subarachnoid hemorrhage (SAH) have no bleeding source and usually have a benign clinical course and outcome. The objectives of this study were to classify the pattern of blood distribution on initial computed tomography (CT) and to correlate it with clinical outcome in aneurysmal (ASAH) and SAH of unknown origin (SAHuO). We reviewed 112 CTs of SAHuO and 104 CTs of ASAH patients. Blood distribution was classified according to a new grading system (type 0-4) and correlated to Hunt and Hess (H&H) grade and modified Rankin scores (MRS) at short- and long-term follow-up. Fifty percent of 112 SAHuO patients were classified as type 0 (no visible blood on CT) or 1 (blood restricted to prepontine cisterns). Most ASAH patients presented with bleeding into the lateral Sylvian fissure (66%; type 3) or with intracerebral hemorrhage (27%; type 4) whereas types 0 and 1 were not observed. SAHuO patients were in better clinical condition on admission than ASAH patients (p < 0.0001). H&H grades of SAHuO patients correlated with the amount of subarachnoid blood according to the new classification (p = 0.004). Short-term outcome was obtained from 100% and long-term outcome from 95% patients (follow-up 29 +/- 31 months). Short- and long-term MRS correlated with blood distribution in SAHuO patients (p = 0.012) and was significantly better than in ASAH patients (p < 0.0001). No correlation was observed between blood distribution, H&H grade, and short- and long-term outcome in aneurysmal patients. In SAH of unknown origin, a new classification allows to predict outcome based on the extent of blood on CT.

Computed Tomographic Angiography: Diagnostic Procedure of Choice in the Management of Subarachnoid Hemorrhage in the Elderly Patient?

Background: The objective of this study was to establish whether 3D computed tomographic angiography (CTA) can be used to determine further management in patients older than 70 years admitted with acute subarachnoid hemorrhage (SAH). Patients and Methods: CTA evaluation included analysis of the source images, image-slice-based multiplanar reconstruction, multi-intensity projection (MIP) and finally 3-dimensional rendering. The location and size of the aneurysm, its precise anatomical morphology and the configuration of the circle of Willis were evaluated. Based on these findings, surgery, endovascular coiling or conservative management was selected. Results: Between October 2001 and June 2005, 44 patients over 70 years of age (38 females, 6 males) were admitted to our neurosurgical department with acute SAH. All patients underwent CTA, and additional 2D digital subtraction angiography (2D-DSA) was performed in 14 patients. Forty-five aneurysms (38 ruptured and 7 unruptured) were diagnosed. Six patients were found to have SAH of unknown origin (no aneurysm on CTA nor 2D-DSA). In 20 patients surgery was performed, in 10 patients endovascular coiling of the aneurysm was carried out, and 12 patients were treated conservatively. The findings on CTA and 2D-DSA could be compared for 26 patients (59%). Correlation between CTA and 2D-DSA was good in 25 of these cases (96%). Glasgow Outcome Scale scores of 4 or 5 were calculated for 37% of the operated patients, 27% of those treated with coils, and 36% of the patients treated conservatively. Conclusion: In older patients with degenerative vascular diseases, CTA can replace 2D-DSA in most cases if the image quality is excellent and analysis is performed carefully.

Subarachnoid hemorrhage of unknown origin and the basilar artery configuration

It is unclear whether the configuration of the basilar artery (BA) in patients with subarachnoid hemorrhage (SAH) of unknown origin is comparable to that in normal subjects or whether there are differences which may help to identify the origin. We studied the BA configuration in 57 patients with SAH of unknown origin (10%), who were identified in a prospectively collected series of 549 SAH patients consecutively admitted to our service over a 9-year period. There were 30 patients (53%) with non-perimesencephalic SAH and 27 with perimesencephalic SAH (47%). According to a standardized algorithm we determined, on straight anteroposterior digital subtraction angiography (DSA), the width of the proximal BA segment at the origin of the anterior inferior cerebellar artery and the width of the most distal BA segment between the superior cerebellar arteries and the posterior cerebral arteries. Based on these measurements we calculated the distal–proximal BA ratios and compared them to the ratios obtained in a control group of 31 patients who had DSA for reasons other than aneurysmal SAH. The mean ratio in patients with non-perimesencephalic SAH of unknown origin was 1.150 (range: 1.080–1.230). In patients with perimesencephalic SAH of unknown origin it was 1.156 (range: 1.120–1.250). In the control group the mean ratio was 1.163 (range: 1.125–1.200). There are no variations in the configurations of the BA which could possibly explain the cause of this type of SAH or clarify the origin of hemorrhage.

Subarachnoid Hemorrhage Associated with Angiographic “Stenotic” or “Occlusive” Lesions in the Carotid Circulation

Background It has been assumed that dissecting aneurysms presenting with subarachnoid hemorrhage (SAH) are extremely rare in the carotid circulation. This may be partially attributed to the difficulty in their diagnosis. The documented angiographic findings include arterial narrowing or occlusion. The purpose of the present study is to investigate the origin of SAH associated with “stenotic” or “occlusive” lesions, which might have been categorized into “SAH of unknown origin.” Methods Between April 1984 and June 1994, 580 patients underwent thorough angiographic investigation to determine the origin of their nontraumatic SAH. Of these patients, five patients had as the only lesion suspected as the source of SAH a single stenosis or occlusion in the carotid circulation that was revealed at the first angiography performed within 48 hours following the onset. We detail these five patients and discuss the current strategy for the treatment of SAH associated with stenotic or occlusive lesions in the carotid circulation. Results Arterial narrowing or occlusion were located in the internal carotid artery (ICA) in two patients, in the middle cerebral artery (MCA) in two patients, and in the posterior communicating artery in one patient. Three patients underwent operation (circumferential wrapping with cotton gauze), and dissecting aneurysms were confirmed in all of them. They all attained good recovery without rebleeding over a long-term period. Two patients died of fatal rebleeding on day 8 and on day 9 while awaiting the second angiography. In one of the patients with ICA stenosis, autopsy revealed a lacerated ICA without a definite saccular aneurysm. In the last patient with M2 occlusion, dissecting aneurysm was strongly suspected from the clinical course. Conclusion To prevent early fatal rebleeding, exploratory craniotomy for angiographic stenotic and occlusive lesions associated with SAH may be justified if all underlying conditions are met, because they may likely include dissecting aneurysms: (1) single stenotic or occlusive, (2) surgically accessible, and (3) consistent with the localization of SAH from CT scan.

クモ膜下出血例における動脈解離の病理形態

An intracranial artery dissection has been recognized as a proper and definite clinical entity associated with subarachnoid hemorrhage (SAH), but true clinicopathological features of this disease have not been adequately elucidated. In this study, we investigated the pathological features ith angiographic correlates of 10 autopsied cases of an intracranial artery dissecting aneurysm and related lesions with SAH, including a case of dorsal wall aneurysm of the internal carotid artery or unknown-origin SAH.Pathological study revealed that all 10 patients had a ruptured site on the lateral wall of the basal artery, and these lesions were classified into the following 3 categories: 1) fusiform dilatation, 2) lateral protrusion, 3) no dilatation. Three lesions of “fusiform dilatation” formed anenlarged aneurysm with false lumen and were thought to be a typical dissecting aneurysm. Four lesions of “lateral protrusion,” including ICA dorsal aneurysm, had no false lumen and formed a pseudoaneurysm at the arterial wall not related to the arterial divisions. Three other lesions of “no dilatation” were clinically diagnosed as SAH of unknown origin, although angiographic finding of diffuse narrowing was oberved at the ruptured site. Intra-wall dissecting hemorrhage without luminal connection was histopathologically identified as an origin of SAH.Some characteristic information revealed in the previous reports was included in this classification, and good correlation between the pathological features and angiographic findings was seen. We conclude that this classification should be useful in discussions of the various clinicopathological subjects of the intracranial artery dissection.

Memory dysfunction in mild aphasics.

The effect of mild aphasia (n = 9), as a result of subarachnoid haemorrhage (SAH), was evaluated against one matched (sex, age, and education) control group suffering from SAH of unknown origin without aphasia, and against one matched healthy control group. According to aphasia testing (Reinvang & Engvik, 1980), criteria for a classical diagnosis were not met. Therefore, the patients were characterized as mild aphasics: They generally displayed intact audo-verbal comprehension and repetition abilities, and they demonstrated a fluent, spontaneous speech. However, they showed phonemic and semantic paraphasias, with self-corrections; a few patients displayed alexia and agraphia. Memory performance of these three groups was evaluated by a neuropsychological test battery, designed to tap various components of verbal memory function. From the results it was concluded that: (a) Short-term memory is impaired, as regards the phonological loop and the central executive in working memory, whereas maintenance rehearsal is unaffected, given that the demands on phonological coding is minimized, (b) long-term memory is also generally impaired, whereas long-term learning and forgetting by means of subject-performed tasks proceeds within a normal range. Impairments were hypothesized to reflect less efficient central executive functions of working memory, involving generation of less appropriate semantic codes and phonological representations, (c) mildly aphasic patients are not subjectively aware of their own memory deficits, and (d) aphasia classification by means of standard procedures do not sufficiently characterize the nature of a mildy aphasic patient's memory problems.

Dorsal internal carotid artery aneurysms with special reference to angiographic presentation and surgical management.

Aneurysms arising from the dorsal wall of the internal carotid artery are rare. The authors surgically treated twenty dorsal internal carotid artery aneurysms. Pre-operative angiographic findings were reviewed and classified into three types. Eleven aneurysms projecting superiorly on the lateral angiogram were found to be adherent to the base of the frontal lobe by the pterional approach. Five aneurysms which had been superimposed with the internal carotid artery on the lateral angiogram were found adhered to the medial surface of the temporal lobe. Four aneurysms not seen on the angiogram had no adhesion. Two aneurysms, which had not been seen on the initial angiograms, were visualized on the angiograms taken during the period of vasospasm. This type of aneurysms can be the source of a subarachnoid haemorrhage of unknown origin and requires repeated examinations. Premature rupture occurred intra-operatively in five cases and postoperative bleeding was encountered in two. Clipping technique is discussed from the viewpoint of preventing intra- and postoperative rupture.

Subarachnoid haemorrhage of unknown aetiology.

Eighty-six of 996 patients with primary subarachnoid haemorrhage (SAH) had negative pan-angiography studies. These 86 patients with subarachnoid haemorrhage of unknown origin (SAH-NUD) were compared with 853 patients sustaining an aneurysmal bleed (SAH-A) admitted during the same period 1980-1989. The age and sex distribution of both groups were similar. The SAH-NUD group was in better condition on admission, with less blood evident on CT scan. All 16 (repeat control) angiography studies in the SAH-NUD group were negative. During a follow-up period ranging from 1 to 10 years (mean 5.4 years), two patients experienced rebleeding with negative repeat angiographies and subsequent total recovery. Using the Glasgow Outcome Scale (GOS) the final outcome was good in 86% of the study group and 54% of the aneurysm group. However, half of the SAH-NUD patients complained of persistent symptoms at long-term follow-up. Thus, despite a generally good prognosis, for a given individual SAH-NUD may be catastrophic with many residual symptoms persisting for the rest of the person's life.

Subarachnoid haemorrhage of unknown origin: clinical and tomographical aspects.

65 patients with negative but technically satisfactory 4 vessel angiography - all admitted to our Department in the years 1976-1983 - were evaluated in the present study. CT scan was undertaken in all cases (in 47 cases within 4 days of haemorrhage). Arterial hypertension was present on admission in 9% of cases. The period of follow-up ranged from 4 to 11 years, with a mean of 5.3 years. The study group was compared to a control group, comprising 760 patients with subarachnoid haemorrhage from ruptured aneurysms, admitted during the same period. Clinical grade on admission (Hunt's classification) was better in patients belonging to the study group. The amount of cisternal deposition on CT scan was less significant than in patients with ruptured aneurysms, and the deposition was often atypical (circumpeduncular, ambiental, and/or tentorial). Clinical deterioration associated with vasospasm was observed in 5% of patients in this study and in 27% of patients in the control group. In patients with a consistent or thick cisternal layer (CT scan "at risk") the incidence of clinical vasospasm was 21%, against 47% in controls. One or more rebleedings occurred in 12% of patients in the study group, against 25% of patients in the control group. A significant ventricular dilatation was observed in 15% of patients in the first group (requiring a shunt in 8%), against 25% of patients in the second group (requiring a shunt in 11%). Final outcome was favourable in 95% of patients in this study group and in 63% of patients in the control group, with a mortality rate of 5% in the first group and 32% in the second group.

Subarachnoid haemorrhage of unknown origin.

This study concerns 64 patients with angiographically negative subarachnoid haemorrhage (SAH) hospitalized in the period 1970-1982. Requisites for inclusion in the study were adequate angiographic demonstration of the carotid and vertebrobasilar systems and no clinical signs of spinal SAH or spontaneous intracerebral haematoma. The clinical data on the 64 cases confirm the close similarity, except for the prognostic factors, between angiographically negative SAH and SAH secondary to rupture of an intracranial saccular aneurysm. The study underlines the benign character of the clinical course and of the medium and long-term prognosis of the condition under study. In view of this, the hypothesis advanced sometime ago relating angiographically negative SAH to the rupture of microaneurysms (phi less than 2 mm) of the large cerebral arteries with subsequent complete repair of the artery wall, or to the spontaneous thrombosis of intracranial saccular aneurysms, with the possibility of subsequent recanalization and risk of fresh rupture, would appear to be a reasonable one.