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

Abstract

N oNtraumatic subarachnoid hemorrhage (SAH) accounts for approximately 5% of all stroke admissions in the United States each year, with an estimated incidence of 10-15 cases per 100,000 population. 1,16 Aneurysms and other vascular abnormalities are well-documented causes of nontraumatic SAH; however, in 10%-20% of cases, no underlying vascular etiology is found, and the source of hemorrhage remains unknown. 5,15,18,26,28 Patients with an SAH of unknown etiology typically have a benign hospital course and are discharged to home in good condition.While the clinical outcome of these patients has been abbreviatioNs AVM = arteriovenous malformation; BRAT = Barrow Ruptured Aneurysm Trial; CTA = CT angiography; CTN = CT negative; DSA = digital subtraction angiography; EVD = external ventricular drain; GOS = Glasgow Outcome Scale; HH = Hunt and Hess; IQR = interquartile range; IVH = intraventricular hemorrhage; LOS = length of hospital stay; MRA = MR angiography; mRS = modified Rankin Scale; PMH = perimesencephalic hemorrhage; SAH = subarachnoid hemorrhage; VP = ventriculoperitoneal. obJect 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). methods 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. results 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. coNclusioNs 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.

Cerebral Angiographic Findings in Non-Traumatic Intracranial Hemorrhage: A Single Center Experience in the West of Iran

“…Increased age has been recognized as a risk factor of hemorrhage; however, extreme old age is protective, decreasing the risk of hemorrhage [12,16,19,22,29]. In the present work, women at their sixth decade of life consisted most of the patients as in some other studies [9,11,25,30]. The majority of studies have reported a female-to-male ratio of about 1.09-1.42 [23,31,32].…”

“…Causes suggested for inducing false negative angiography may include technical errors such as incomplete angiographic views, presence of vasospasm (especially on the 3rd to 14th day of hemorrhage), presence of hematoma mass-effect, existence of thrombosis in the neck of aneurysms and injection of hyperosmolar contrast [20][21][22][23][24][25][26][27]. According to most reports by other researchers, the maximum number of cases with non-traumatic intracranial hemorrhage were detected in age range of 50-59 years old [11,14,15,19,28]. Increased age has been recognized as a risk factor of hemorrhage; however, extreme old age is protective, decreasing the risk of hemorrhage [12,16,19,22,29].…”

“…Intracranial aneurysms are the most common causes of non-traumatic intracranial hemorrhage, occurring in 60%-85% of cases [9,10]. The most common place of intracranial aneurysms is the circle of Willis and its immediate branches [11][12][13]. The location and the size of the aneurysms are the important factors influencing management and prognosis of patients [14,15].…”

Increasing numbers of nonaneurysmal subarachnoid hemorrhage in the last 15 years: antithrombotic medication as reason and prognostic factor?

“…However, in up to 20% of patients with SAH, results of cerebral angiography, CT, and MRI are negative for aneurysms or other vascular malformations. 2,7,11 More recent data show an increasing number of cases of spontaneous SAH 18,24 as well as nonaneurysmal SAH (NASAH). 15,16 Long-term dipyridamole and warfarin use were associated with an increased risk for aneurysmal SAH (aSAH), whereas the data for low-dose acetylsalicylic acid (LDA) were inconsistent.…”

Analysis of saccular aneurysms in the Barrow Ruptured Aneurysm Trial

“…The relatively benign history of this subgroup of patients has been well documented in the literature. 1 Although these patients were initially randomized to clipping or coiling, they never received treatment and are not considered further in this analysis. The sources of SAH in the remaining 414 patients are summarized in Table 2.…”