Recurrent idiopathic perimesencephalic subarachnoid hemorrhage

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) is a benign variant of SAH defined by clinical symptoms of SAH, a characteristic pattern of extravasated blood on noncontrast CT, and negative findings on cerebral angiography. This syndrome carries a favorable prognosis with reportedly no risk of recurrent hemorrhage. The authors present the case of a 62-year-old man with no significant medical history who experienced recurrent, spontaneous episodes of PNSAH within the course of 5 months. No precipitating causes were identified, but the patient had been involved in exertional activities preceding both events. To the authors' knowledge, this is the first conclusive report of recurrent, idiopathic PNSAH. The findings suggest that while the risk of recurrent hemorrhage in the setting of PNSAH is far less than that for aneurysmal SAH, rebleeding can still occur. The authors speculate on the etiology of this rare phenomenon.     

Quadrigeminal variant of perimesencephalic nonaneurysmal subarachnoid hemorrhage

OBJECTIVE: Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSH) is a benign entity with a low risk of rebleeding. The most widely accepted definition emphasizes the presence of blood ventral to the midbrain or pons on early computed tomography. We sought to determine the frequency of PNSH with blood centered in the quadrigeminal cistern. METHODS: We reviewed a prospectively collected database of all patients admitted to our institution over a 2.5-year period with subarachnoid hemorrhage (SAH) and identified PNSH patients from early computed tomographic scans and negative four-vessel angiograms. RESULTS: Of 220 SAH patients, we identified 9 with PNSH. Two (22%) of these patients had SAH centered in the quadrigeminal cistern without pretruncal blood, negative repeat angiograms, and an uncomplicated clinical course. CONCLUSION: Quadrigeminal SAH is a variant of PNSH that is not well described in the literature. It may comprise up to one-fifth of PNSH cases and carries a similar benign prognosis.     

Ethnic differences in risk factors for subarachnoid hemorrhage

OBJECT: Studies on risk factors for subarachnoid hemorrhage (SAH) show heterogeneity. For example, hypertension has been found to be a significant risk factor in some studies but not in others. The authors hypothesized that differences in the ethnicity of the populations studied could account for these findings. METHODS: A metaanalysis was performed using 17 case-control and 10 cohort studies that met specified inclusion criteria. The authors used a random-effect model to calculate the pooled effect estimates for current smoking, hypertension, and alcohol consumption. A meta-regression analysis was performed using the ethnic composition of the study populations as a covariate. Studies were classified as multiethnic or monoethnic, and the pooled effect estimates were compared. RESULTS: Analysis of the cohort studies yielded a pooled effect estimate or risk ratio of 3.18 (95% confidence interval [CI] 2.37-4.26) for current smoking, 3.05 (95% CI 2.09-4.44) for hypertension, and 2.46 (95% CI 1.42-4.24) for alcohol consumption at a rate of 150 g/week or more. The results were similar for the case-control studies. For current smoking, the ethnic composition of the study population was a statistically significant predictor of heterogeneity among case-control studies (p < 0.001, even after application of the Bonferroni correction). The risk for SAH among current smokers was higher in multiethnic populations (odds ratio 3.832) than in monoethnic populations (odds ratio 2.487). CONCLUSIONS: The results of this metaanalysis suggest that differences in susceptibility to the harmful health effects of smoking may be one cause of the observed differences in SAH incidence for different ethnic groups. The role of ethnicity in risk factors for SAH should be considered in future studies.     

Comparison between perimesencephalic nonaneurysmal subarachnoid hemorrhage and subarachnoid hemorrhage caused by posterior circulation aneurysms

OBJECT: Some authors have questioned the need to perform cerebral angiography in patients presenting with a benign clinical picture and a perimesencephalic pattern of subarachnoid hemorrhage (SAH) on initial computerized tomography (CT) scans, because the low probability of finding an aneurysm does not justify exposing patients to the risks of angiography. It has been stated, however, that ruptured posterior circulation aneurysms may present with a perimesencephalic SAH pattern in up to 10% of cases. The aim of the present study was twofold: to define the frequency of the perimesencephalic SAH pattern in the setting of ruptured posterior fossa aneurysms, and to determine whether this clinical syndrome and pattern of bleeding could be reliably and definitely distinguished from that of aneurysmal SAH. METHODS: Twenty-eight patients with ruptured posterior circulation aneurysms and 44 with nonaneurysmal perimesencephalic SAH were selected from a series of 408 consecutive patients with spontaneous SAH admitted to the authors' institution. The admission unenhanced CT scans were evaluated by a neuroradiologist in a blinded fashion and classified as revealing a perimesencephalic SAH or a nonperimesencephalic pattern of bleeding. Of the 28 patients with posterior circulation aneurysms, five whose grade was I according to the World Federation of Neurosurgical Societies scale were classified as having a perimesencephalic SAH pattern on the initial CT scan. The data show that the likelihood of finding an aneurysm on angiographic studies obtained in a patient with a perimesencephalic SAH pattern is 8.9%. Conversely, ruptured aneurysms of the posterior circulation present with an early perimesencephalic SAH pattern in 16.6% of cases. CONCLUSIONS: This study supports the impression that there is no completely sensitive and specific CT pattern for a nonaneurysmal SAH. In addition, the authors believe that there is no specific clinical syndrome that can differentiate patients who have a perimesencephalic SAH pattern caused by an aneurysm from those without aneurysms. Digital subtraction angiography continues to be the gold standard for the diagnosis of cerebral aneurysms and should be performed even in patients who have the characteristic perimesencephalic SAH pattern on admission CT scans.     

Neuropsychological assessments in patients with aneurysmal subarachnoid hemorrhage, perimesencephalic SAH, and incidental aneurysms

Subarachnoid hemorrhage (SAH) is known to be associated with long-term cognitive deficits. Neurosurgical manipulation on the brain itself has been reported to have influence on neuropsychological sequelae. The following is a comparative study on perimesencephalic and aneurysmal subarachnoid hemorrhage patients as well as elective aneurysm patients that was carried out to determine the isolated and combined impact of surgical manipulation and hemorrhage, respectively, on long-term neuropsychological outcome. Inclusion criteria were good neurological recovery at discharge (modified Rankin Scale 0 or 1) without focal neurological deficit. Standardized psychological testing covered attention, memory, executive functions, and mood. Thirteen aneurysmal SAH patients, 15 patients undergoing elective clipping, and 14 patients with perimesencephalic SAH were analyzed. Standardized neuropsychological testing and social/professional history questionnaires were performed 2 years (mean) after discharge. Memory impairment and slower cognitive processing were found in the aneurysmal and perimesencephalic SAH groups, while elective aneurysm patients showed signs of impaired attention. However, compared with norm data for age-matched healthy controls, all groups showed no significant test results. In contrast, signs of clinical depression were seen in 9/42 patients, 45 % of all patients complained of stress disorders and 55 % of patients were unable to work in their previous professions. Nearly normal neuropsychological test results on long-term follow-up in SAH patients were unexpected. However, a 50 % rate of unemployment accompanied with stress disorders and depression manifests insufficient social and workplace reintegration. Therefore, even more specific rehabilitation programs are required following inpatient treatment to attain full recovery.     

Endoscopic third ventriculostomy for hydrocephalus after perimesencephalic subarachnoid hemorrhage: initial experience in three patients

Background  

To review the outcome after endoscopic third ventriculostomy (ETV) for symptomatic, persistent hydrocephalus in three patients with perimesencephalic angiographically negative subarachnoid hemorrhage (PNH) who were dependent on an external ventricular drain (EVD).     

Significance of a small bulge on the basilar artery in patients with perimesencephalic nonaneurysmal subarachnoid hemorrhage. Report of two cases

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (SAH) is a distinct type of hemorrhage with a characteristic bleeding pattern and an excellent clinical outcome. The cause of this benign form of SAH remains unknown. The authors report on two cases of perimesencephalic nonaneurysmal SAH in which a small bulge on the basilar artery (BA) was demonstrated on three-dimensional rotational angiography studies. Based on data from these cases, one may infer that the lesion on the BA is responsible for the SAH. The possible pathogenesis is discussed.     

Leukocytosis as an independent risk factor for cerebral vasospasm following aneurysmal subarachnoid hemorrhage

OBJECT: The identification of patients at an increased risk for cerebral vasospasm after subarachnoid hemorrhage (SAH) may allow for more aggressive treatment and improved patient outcomes. Note, however, that blood clot size on admission remains the only factor consistently demonstrated to increase the risk of cerebral vasospasm after SAH. The goal of this study was to assess whether clinical, radiographic, or serological variables could be used to identify patients at an increased risk for cerebral vasospasm. METHODS: A retrospective review was conducted in all patients with aneurysmal or spontaneous nonaneurysmal SAH who were admitted to the authors' institution between 1995 and 2001. Underlying vascular diseases (hypertension or chronic diabetes mellitus), Hunt and Hess and Fisher grades, patient age, aneurysm location, craniotomy compared with endovascular aneurysm stabilization, medications on admission, postoperative steroid agent use, and the occurrence of fever, hydrocephalus, or leukocytosis were assessed as predictors of vasospasm. Two hundred twenty-four patients were treated for SAH during the review period. One hundred one patients (45%) developed symptomatic vasospasm. Peak vasospasm occurred 5.8 +/- 3 days after SAH. There were four independent predictors of vasospasm: Fisher Grade 3 SAH (odds ratio [OR] 7.5, 95% confidence interval [CI] 3.5-15.8), peak serum leukocyte count (OR 1.09, 95% CI 1.02-1.16), rupture of a posterior cerebral artery (PCA) aneurysm (OR 0.05, 95% CI 0.01-0.41), and spontaneous nonaneurysmal SAH (OR 0.14, 95% CI 0.04-0.45). A serum leukocyte count greater than 15 x 10(9)/L was independently associated with a 3.3-fold increase in the likelihood of developing vasospasm (OR 3.33, 95% CI 1.74-6.38). CONCLUSIONS: During this 7-year period, spontaneous nonaneurysmal SAH and ruptured PCA aneurysms decreased the odds of developing vasospasm sevenfold and 20-fold, respectively. The presence of Fisher Grade 3 SAH on admission or a peak leukocyte count greater than 15 x 10(9)/L increased the odds of vasospasm sevenfold and threefold, respectively. Monitoring of the serum leukocyte count may allow for early diagnosis and treatment of vasospasm.     

Hypertension as a risk factor for epilepsy after aneurysmal subarachnoid hemorrhage and surgery

A prospective, consecutive series of 307 patients with aneurysmal subarachnoid hemorrhage ranging from Grades 1 to V according to the classification of Hunt and Hess on admission were evaluated to determine the incidence of epilepsy 1 to 3 years (mean, 1.4 years) after aneurysmal subarachnoid hemorrhage (SAH) and surgery. Sixty-three patients had died and one patient was lost to follow-up. Twenty-nine patients developed epileptic seizures after the SAH and surgery. The mean time from the SAH to epileptic seizure varied from 0 days (day of the SAH) to 2 years (mean, 6.7 months). The seizures were classified as focal in 9 patients (31%) and as generalized in 20 patients (69%). All patients received anticonvulsant medication after more than one seizure. The risk factors for development of posthemorrhagic/postoperative epilepsy were, in order of importance: a history of hypertension; an infarct on late computed tomographic scan; and the duration of coma after the ictus. Of the 85 patients with histories of hypertension, 17 (20.0%) developed epilepsy. Only 12 (5.4%) of the 222 nonhypertensive patients developed epileptic seizures. The difference between the groups was significant (P = 0.0001). Computed tomographic scans were undertaken in 237 patients 1 to 3 years (mean, 1.4 years) after the SAH and surgery. Postoperative epilepsy was significantly associated with infarcts visualized on computed tomographic scan (P = 0.0005).     

Sex-related differences in patients treated surgically for aneurysmal subarachnoid hemorrhage

Sex-related differences were examined in the clinical course of patients treated surgically for aneurysmal subarachnoid hemorrhage. Retrospective analyses were carried out to evaluate sex-related differences in aneurysm location, aneurysm size, preoperative neurological condition, preoperative computed tomography findings, and outcome among 2577 patients who underwent surgical repair of ruptured aneurysms. The internal carotid artery was most frequently affected in women and the anterior cerebral artery in men. Intracerebral or intraventricular hematoma was more common in men than in women. Some differences may be related to the location of the aneurysm. Sex-related differences were prominent in the 5th decade of life. These findings might be related to the menopause. Sex hormones may be involved in aneurysm formation.     

Release of endothelium-derived relaxing factor after subarachnoid hemorrhage

The purpose of this study was to determine the cause of the loss of endothelium-dependent relaxation observed in chronic cerebral vasospasm. A bioassay system was developed to measure the release of endothelium-derived relaxing factor (EDRF) from canine basilar arteries. Subarachnoid hemorrhage (SAH) was induced in dogs by two injections of autologous blood into the cisterna magna. Angiograms were performed on the 7th day after SAH to check the presence of chronic vasospasm. The animals were sacrificed on the 8th day, and in vitro experiments were performed on rings harvested from the basilar artery. These confirmed loss of endothelium-dependent relaxation in response to bradykinin and arginine vasopressin in the group with SAH. The basilar arteries were perfused with modified Krebs-Ringer solution. The perfusate was bioassayed with a ring of coronary artery without endothelium (bioassay ring). The release of the EDRF was detected by relaxation of the bioassay ring contracted with prostaglandin F2 alpha. Arginine vasopressin and bradykinin added to the perfusate upstream of the basilar artery caused concentration-dependent release of the EDRF. The direct effect of these peptides on the smooth muscle of the bioassay ring was to cause contraction. The release of the EDRF was identical in basilar arteries from the control and the SAH groups. These results indicate that the release of the EDRF is not impaired during chronic vasospasm, and thus that the loss of the endothelium-dependent relaxation is due to a decreased transfer of the EDRF or a reduced responsiveness of the smooth muscle to the factor.     

Decrease in platelet count as an independent risk factor for symptomatic vasospasm following aneurysmal subarachnoid hemorrhage

OBJECT: Increased platelet consumption is expected in patients with cerebral vasospasm, according to data from clinical and experimental studies. The authors investigated sequential changes in platelet counts in patients with subarachnoid hemorrhage (SAH) and the difference in platelet consumption between patients with and those without symptomatic vasospasm (SV). Variables related to platelet count as well as other clinical and radiological variables were analyzed as independent predictors of SV. METHODS: One hundred consecutive patients who had undergone surgery within 48 hours after SAH onset were entered in the study. Clinical and radiological variables and blood cell counts, including red blood cells, white blood cells, and platelets, after SAH were retrospectively examined. Twenty of these variables were entered into univariatete and multivariate analyses to determine predictors for SV. After SAH, the platelet count decreased to a minimum and then increased rapidly to levels greater than those recorded on admission. This change was specific to SAH, and platelet consumption was more severe in patients with SV than in those without. There were three independent predictors of SV: a ratio of the lowest platelet count and the admission count greater than 0.7 (odds ratio [OR] 0.322, 95% confidence interval [CI] 0.124-0.834, p = 0.0196) and a history of hypertension (OR 0.338, 95% CI 0.126-0.906, p = 0.0311) were negatively significant (that is, decreases the occurrence of SV), and a Fisher Grade 3 (OR 4.42, 95% CI 1.48-13.2, p = 0.0077) was positively significant (that is, increases the occurrence of SV). CONCLUSIONS: The association between a decrease in platelet count and the occurrence of SV indicates the important role of platelets in the pathophysiology of vasospasm following SAH.     

Aneurysms and subarachnoid hemorrhage.

Most unruptured intracranial aneurysms that produce neuro-ophthalmologic signs arise from the junction of the internal carotid and posterior communicating arteries. These aneurysms typically compress the third nerve in the subarachnoid space. Compression of cranial nerves within the cavernous sinus is less common, resulting in single or multiple and often painful ocular motor nerve pareses. Unruptured aneurysms of the proximal and distal segments of the intracranial portion of the internal carotid artery can compress the anterior visual pathways and cause visual loss. Ocular symptoms and signs may be the presenting manifestations of intracranial aneurysms. Prompt recognition of an aneurysm prior to rupture can prevent devastating intracerebral or subarachnoid hemorrhage. Moreover, visual complications are a not infrequent source of morbidity in those patients surviving acute intracranial bleeding. Recent advances in noninvasive neuroimaging and endovascular therapies facilitate early diagnosis and treatment and therefore may limit such complications.     

Painful third nerve palsy in a patient with perimesencephalic subarachnoid haemorrhage

A patient with perimesencephalic subarachnoid haemorrhage (PMSAH) developed a delayed third nerve palsy. Three formal cerebral angiograms, a computed tomography cerebral angiogram and a magnetic resonance angiogram all failed to reveal a vascular abnormality. Further investigations did not show any medical cause for the palsy. This appears to be the first case report of a patient with PMSAH presenting with a painful third nerve palsy.     

Characterization of perioperative seizures and epilepsy following aneurysmal subarachnoid hemorrhage

OBJECT: The reported incidence, timing, and predictive factors of perioperative seizures and epilepsy after subarachnoid hemorrhage (SAH) have differed considerably because of a lack of uniform definitions and variable follow-up periods. In this study the authors evaluate the incidence, temporal course, and predictive factors of perioperative seizures and epilepsy during long-term follow up of patients with SAH who underwent surgical treatment. METHODS: Two hundred seventeen patients who survived more than 2 years after surgery for ruptured intracranial aneurysms were enrolled and retrospectively studied. Episodes were categorized into onset seizures (< or = 12 hours of initial hemorrhage), preoperative seizures, postoperative seizures, and late epilepsy, according to their timing. The mean follow-up time was 78.7 months (range 24-157 months). Forty-six patients (21.2%) had at least one seizure post-SAH. Seventeen patients (7.8%) had onset seizures, five (2.3%) had preoperative seizures, four (1.8%) had postoperative seizures, 21 (9.7%) had at least one seizure episode after the 1st week postoperatively, and late epilepsy developed in 15 (6.9%). One (3.8%) of 26 patients with perioperative seizures (onset, preoperative, or postoperative seizure) had late epilepsy at follow up. The mean latency between the operation and the onset of late epilepsy was 8.3 months (range 0.3-19 months). Younger age (< 40 years old), loss of consciousness of more than 1 hour at ictus, and Fisher Grade 3 or greater on computerized tomography scans proved to be significantly related to onset seizures. Onset seizure was also a significant predictor of persistent neurological deficits (Glasgow Outcome Scale Scores 2-4) at follow up. Factors associated with the development of late epilepsy were loss of consciousness of more than 1 hour at ictus and persistent postoperative neurological deficit. CONCLUSIONS: Although up to one fifth of patients experienced seizure(s) after SAH, more than half had seizure(s) during the perioperative period. The frequency of late epilepsy in patients with perioperative seizures (7.8%) was not significantly higher than those without such seizures (6.8%). Perioperative seizures did not recur frequently and were not a significant predictor for late epilepsy.