Different roles of arteriosclerosis in the rupture of intracranial dissecting aneurysms

Delayed appearance of basilar trunk small atypical aneurysms in nontraumatic, initially angiogram-negative subarachnoid hemorrhage: A report of three patients

BACKGROUND

Repeat angiography will identify vascular pathology in approximately 10% of cases following angiogram-negative subarachnoid hemorrhage (anSAH), but small atypical aneurysms of the basilar artery are very uncommon.

OBJECTIVE

To report a case series of delayed appearance of nontraumatic basilar artery small atypical aneurysms.

METHODS

IRB approval was obtained for this retrospective case series and patient consent was waived.

RESULTS

Herein we report three cases of spontaneous anSAH, all of whom had a negative digital subtraction angiogram (DSA) on admission and all of whom had appearance of a small atypical aneurysms of the upper basilar trunk/apex on follow-up imaging (two during the initial admission and one in a delayed fashion). All three patients were ultimately treated with flow diversion (although one patient underwent attempted coiling that was abandoned due to inability to catheterize the aneurysm).

CONCLUSION

This report highlights the importance of a repeat DSA in cases of anSAH as well as the importance of scrutinizing the basilar trunk for these very small atypical aneurysms that may go unnoticed.

Higher Prevalence and Age Susceptibility of Intracranial Aneurysm in Patients With Acoustic Neuroma

Introduction: The purpose of this study was to verify whether the prevalence of intracranial aneurysm (IA) in patients with acoustic neuroma is greater than that in age- and sex-matched controls and to evaluate the independent risk factors related to the occurrence of IA. Methods: We retrospectively analyzed 231 patients diagnosed with acoustic neuroma at our institute between 2015 and 2019 and 489 controls from the medical examination center. Cerebrovascular angiography was acquired from all subjects to assess the presence of IA or not. The prevalence of IA and risk factors associated with a higher IA occurrence were compared, respectively. Results: Cerebral aneurysms were detected in 23 patients (10.0%) and 11 controls (2.2%). The prevalence of IA was significantly different between patients with acoustic neuroma and controls (p < 0.001), and the difference was mainly reflected in the age of 50 and above. In the subgroup analysis, there were distinct differences in several clinical features including age, hypertension, and tumor volume, and cystic change between patients coexisted with IA or not. However, age was a unique independent risk factor for coexistence of IA in patients with acoustic neuroma after multivariate logistic regression (OR 1.050, 95% CI 1.008-1.093, p = 0.019). Conclusions: Our results demonstrate that patients with acoustic neuroma have a higher prevalence of IA than the general population. Older age is correlated with greater occurrence of IA in these patients.

Nontraumatic, posterior circulation pseudoaneurysm of the basilar artery summit with complete spontaneous resolution: Case report and literature review

Background:

Intracranial pseudoaneurysms are rare vascular defects of arterial walls that are classically the result of traumatic injury, iatrogenic causes, or infection. Idiopathic pseudoaneurysms are seen even less frequently and are often related to atherosclerosis. Pseudoaneurysms are most commonly found along the distal wall of the internal carotid artery, however, can occur at any location in the cerebrovascular circulation. Treatment of these arterial defects is often challenging due to their frail nature.

Case Description:

A 61-year-old male with a history of hypertension presented with a severe, atypical headache without history of trauma. Computed tomography (CT) and computed tomography angiography (CTA) demonstrated diffuse subarachnoid hemorrhage. Imaging demonstrated a 3.5 mm pseudoaneurysm projecting distally from the basilar artery at the apex. Repeated imaging (CTA, digital subtraction angiography) demonstrated decreased size and flow associated within the aneurysm over the following 2 weeks; as such, the patient was managed conservatively. The patient was discharged in neurologically intact condition when imaging at 14 days confirmed complete and spontaneous resolution of the pseudoaneurysm.

Conclusion:

Idiopathic pseudoaneurysms that are commonly associated with atherosclerosis are most commonly managed surgically or endovascularly. Conservative approach may be considered in a select group of patients that exhibit decreased size and/or flow within the aneurysm in repeated imaging; spontaneous resolution was seen in the present case.

State-of-art in surgical treatment of dissecting posterior circulation intracranial aneurysms

Vertebrobasilar (VB) intracranial dissecting aneurysms (IDAs) pose difficult therapeutic issues and are especially among the most difficult to manage surgically. There are, however, some cases where selective aneurysm obliteration by endovascular approach is impossible or is associated with an unacceptable risk of morbidity. This is particularly true when the aneurysm is dissecting, giant, or has a large neck. In such cases, surgical treatment may be the only alternative. Optimal management of these lesions is therefore challenging and treatment decisions have to be made on a case-by-case basis. Ideal treatment should be a complete surgical excision of the lesion; however, this procedure might only be possible after distal and proximal vessel wall occlusion which might not be tolerated by the patient depending on the location of the aneurysm. Therefore, formulation of recommendations concerning the surgical strategy remains still difficult due to inconsistency of surgical outcomes. The literature describing surgical strategy of VB IDAs is varying in quality and content, and many studies deal with only a few patients. In the presented review, the authors summarize the current knowledge on the incidence, pathogenesis, clinical presentation, and diagnostic procedures with special emphasis on surgical treatment of IDAs in posterior circulation.

Epidemiology, pathophysiology, diagnosis, and management of intracranial artery dissection

Spontaneous intracranial artery dissection is an uncommon and probably underdiagnosed cause of stroke that is defined by the occurrence of a haematoma in the wall of an intracranial artery. Patients can present with headache, ischaemic stroke, subarachnoid haemorrhage, or symptoms associated with mass effect, mostly on the brainstem. Although intracranial artery dissection is less common than cervical artery dissection in adults of European ethnic origin, intracranial artery dissection is reportedly more common in children and in Asian populations. Risk factors and mechanisms are poorly understood, and diagnosis is challenging because characteristic imaging features can be difficult to detect in view of the small size of intracranial arteries. Therefore, multimodal follow-up imaging is often needed to confirm the diagnosis. Treatment of intracranial artery dissections is empirical in the absence of data from randomised controlled trials. Most patients with subarachnoid haemorrhage undergo surgical or endovascular treatment to prevent rebleeding, whereas patients with intracranial artery dissection and cerebral ischaemia are treated with antithrombotics. Prognosis seems worse in patients with subarachnoid haemorrhage than in those without.

Stent-assisted coil trapping in a manual internal carotid artery compression test for the treatment of a fusiform dissecting aneurysm

Internal carotid artery (ICA) trapping can be used for the treatment of giant intracranial aneurysms, blood blister-like aneurysms, and fusiform dissecting aneurysms. Fusiform dissecting aneurysms are challenging to treat surgically and endovascularly because of no definite neck and critical perforators. Surgical or endovascular trapping of the ICA with or without an extracranial-intracranial bypass has commonly been used as an effective method to treat these lesions, but balloon test occlusion (BTO) must be performed. Here, we report a case of a ruptured fusiform dissecting aneurysm of the distal ICA, which was successfully treated using an endovascular ICA trapping with a manual ICA compression test instead of BTO.

Treatment of Spontaneous Intradural Vertebral Artery Dissections

Spontaneous intradural vertebral artery dissections may cause subarachnoid hemorrhage and often result in devastating damage. Increased use of noninvasive imaging studies has allowed larger numbers of patients to be diagnosed. In addition, intracranial vertebral artery dissection tends to induce multiple lesions affecting both intracranial vertebral arteries recurrently. Although unruptured dissections in this area usually have a benign nature, some authors have reported on the incidence of rupture from this lesion. Once hemorrhage from a dissecting vessel wall has occurred, it needs to be treated in the acute phase because of the high risk of rebleeding resulting in high morbidity and mortality. From December 2004 to July 2010, we managed 47 patients with spontaneous vertebral artery dissection, 31 patients were ruptured and 16 were unruptured. All patients who suffered from subarachnoid hemorrhage were treated with endovascular procedures. Most of the patients with unruptured dissection received medical therapy, but if the aneurysmal dilatation persisted or grew, surgical interventions were performed. Stenting with or without coils was deployed for 13 patients with posterior inferior cerebellar artery involvement at the site of dissection and/or were affected on the dominant side. In some patients, stenting was performed even if they were in the acute phase. For other ruptured patients, internal coil trappings were performed. Six patients died due to severe initial subarachnoid hemorrhage and one patient, who underwent stent deployment with coils for the dominant vertebral artery, with bilateral dissection continuing to the basilar artery died due to rerupture while the next additional coiling was planning. There were two cases of complications related to the intervention. During the follow-up period no bleeding occurred in any of the patients except for the previously mentioned patient. In conclusion, internal coil trapping or stent placement with or without coils was effective in preventing rebleeding of ruptured vertebral artery dissection. If the dissection is unruptured, it is necessary to detect the risk of bleeding with careful watching and when progress appears to be made, patients should be treated promptly. Stent-assisted therapy for preserving the patency of the parent artery and major branches is a promising treatment for vertebral artery dissection, even in the acute stage of subarachnoid hemorrhage. However, the risk of acute rerupture and recurrence remains even with the porous stent placement with or without coils.

Comparison of clinical characteristics and MR angiography appearance in patients with spontaneous intradural vertebral artery dissection with or without subarachnoid hemorrhage

Object

It is well known that spontaneous intradural vertebral artery dissection (siVAD) is an important cause of nontraumatic subarachnoid hemorrhage (SAH). The factors that influence whether SAH develops, however, remain unclear. The aim of this study was to investigate whether clinical characteristics and imaging findings are different in patients with siVAD with SAH compared to those with siVAD without SAH.

Methods

The authors conducted a retrospective, single-institution study involving patients in whom siVAD developed with or without SAH, between July 2003 and November 2010. Univariate and multivariate analyses were performed to evaluate clinical characteristics and MR angiography findings. The vertebral-union-basilar angle (VUBA) was defined as the most acute angle between line of the basilar artery trunk and line of the vertebral angle (VA) at the vertebral union on 3D MR angiograms.

Results

Among 58 patients with siVAD, 21 developed SAH. The presence of siVAD and SAH was significantly associated with higher rates of current smoking (OR 13; 95% CI 3.6–38; p < 0.0001), dissection of the dominant VA (OR 9.2; 95% CI 2.5–19; p = 0.0004), and unruptured supratentorial nondissecting saccular aneurysms (OR 11; 95% CI 2.1–19; p = 0.0025), and the VUBA of the dominant VA was significantly larger (p < 0.0001, univariate analysis). Multivariate analysis showed that these differences were still significant (p < 0.05).

Conclusions

A larger VUBA of the dominant VA, the presence of unruptured supratentorial nondissecting saccular aneurysms, and current smoking may be factors that predict which patients with siVAD will develop SAH by dominant VAD.

Cocaine mediated apoptosis of vascular cells as a mechanism for carotid artery dissection leading to ischemic stroke

In arterial dissection, blood may enter the arterial wall through an intimal tear, splitting the arterial wall and activating the coagulation cascade at the site of endothelial damage. Dissection of extracranial and intracranial vessels may lead to ischemic stroke through thromboembolic or hemodynamic mechanisms. Major blunt trauma or rapid acceleration-deceleration may cause dissection, but in patients with inherent arterial wall weakness, dissection can occur spontaneously or as a result of minor neck movement. Cocaine use has been associated with dissection of the aortic arch and coronary and renal arteries through cocaine-mediated hypertension. Recent preclinical studies have suggested, however, that cocaine may cause apoptosis of cells in the vascular wall. In this article, we postulate that cocaine may cause apoptosis of vascular endothelial and/or smooth muscle cells, thus weakening the vascular wall and resulting in a dissection-prone state. We review the literature and propose a biological basis for vasculopathy, vascular dissection, and ischemic stroke in the setting of cocaine use. Further research studies on vascular cells, as well as focused analysis of human pathological material, will be important in providing evidence for or against our hypotheses.

Histopathologic characteristics of a saccular aneurysm arising in the non-branching segment of the distal middle cerebral artery

Currently, the characteristics of aneurysms arising in the distal middle cerebral artery (dMCA) are not well understood. Here, we report the case of a 56-year-old woman with a ruptured saccular aneurysm in the M2 segment of the middle cerebral artery (MCA). The patient presented with a disturbance of consciousness, and computed tomography revealed a subarachnoid hemorrhage that angiography disclosed as a result of a saccular-type aneurysmal dilatation in the M2 segment of the left MCA. We excluded infection, inflammation, trauma, and neoplasia as causes of the aneurysm. Pathologic examination confirmed a ruptured saccular aneurysm of the dMCA that was unrelated to a branching zone. The aneurysmal wall was composed primarily of alphaSMA-positive and calponin/desmin-negative spindle cells and lacked internal elastic lamina, which was completely disrupted at the neck of the aneurysm. There was a strong positive immunoreactivity for matrix metalloproteinases (MMPs) 1, 2, and 9 in the spindle cells of the aneurysmal wall. In contrast, tests for MMP-8 were negative. The parent artery showed thickening of both the intima and media, with preservation of the internal elastic lamina. Atherosclerosis was not detected in either the parent artery or aneurysm. These findings suggest that an overexpression of MMPs may contribute to the development of saccular aneurysms in regions of the arterial trunk unrelated to branching zones.

Intracranial vertebral artery dissection resulting in fatal subarachnoid hemorrhage: clinical and histopathological investigations from a medicolegal perspective

Object

Subarachnoid hemorrhage (SAH) due to a ruptured intracranial vertebral artery (VA) dissection sometimes results in a sudden fatal outcome. The authors analyzed the relationship between clinical features and histopathological characteristics among fatal cases to establish valuable information for clinical diagnostics and prophylaxis.

Methods

This study included 58 medicolegal autopsy cases of ruptured intracranial VA dissection among 553 fatal nontraumatic cases of SAH that occurred between January 2000 and December 2007. Their clinical features were obtained from autopsy records. Histopathological investigations were performed on cross-sections obtained from all 4-mm segments of whole bilateral intracranial VAs and prepared with H & E and elastica van Gieson staining.

Results

The autopsy cases included 47 males and 11 females, showing a marked predilection for males. The mean age was 46.8 ± 7.7 years, with 78% of the patients in their 40s or 50s. Hypertension was the most frequently encountered history; it was found in 36% of cases from clinical history and in 55% of cases based on autopsy findings. Prodromal symptoms related to intracranial VA dissections were detected in 43% of patients. Headache or neck pain lasting hours to weeks was a frequent complaint. Of patients with prodromal symptoms, 44% had consulted doctors; however, in none of these was SAH or intracranial VA dissection diagnosed at a preventable stage.

Autopsy revealed fusiform aneurysms with medial dissecting hematomas. Apart from ruptured intracranial VA dissection, previous intracranial VA dissection was detected in 25 cases (43%); among them, 10 showed previous dissection of the bilateral intracranial VAs. The incidence of prodromal symptoms (60%) among the patients with previous intracranial VA dissection was significantly higher than that (30%) among cases without previous dissection (chi-square test; p = 0.023). Most previous intracranial VA dissections formed a single lumen resembling nonspecific atherosclerotic lesions, with the exception of 3 cases (12%) with a double lumen.

Conclusions

Intracranial VA dissection resulting in fatal SAH frequently affects middle-aged men with untreated hypertension. Related to the high frequency of prodromal symptoms, latent previous intracranial VA dissection was histopathologically detected. Furthermore, intracranial VA dissection tends to induce multiple lesions affecting both intracranial VAs recurrently. This suggests the importance of an awareness of sustained whole intracranial VA vulnerability for the prevention of recurrence. The incidence of prodromal symptoms was significantly higher among patients with previous intracranial VA dissections. Thus, earlier diagnosis of intracranial VA dissections at the unruptured stage is desirable for prophylaxis against fatal SAH.

Nontraumatic and noninfectious pseudoaneurysms on the circle of Willis: 2 case reports and review of the literature

BACKGROUND

Nontraumatic and noninfectious pseudoaneurysms with similar shape of true saccular aneurysm on the circle of Willis are rare.

CASE DESCRIPTIONS

Two patients with such pseudoaneurysms are reported, one is a 37-year-old man, the other is a 50-year-old woman. They presented with sudden headache; CT scan showed subarachnoid hemorrhage in both. Thorough medical history had been reviewed; physical and laboratory examination had been made but demonstrated no evidence of craniocerebral injury and intracranial or systematic infection. On the cerebroangiogram, they represented the same imageologic changes of true saccular aneurysm, but subsequent operation and pathologic examination revealed that they were pseudoaneurysms consisting of blood clot enclosed with a layer of connective tissue; degenerative changes may have contributed to their formation.

CONCLUSION

Careful attention should be given in classifying these saccular pseudoaneurysm from true saccular aneurysms because of their friable nature, tendency of rupture, and different pathologic findings.

Subarachnoid hemorrhage as a presentation of basilar artery dissection

INTRODUCTION

Subarachnoid hemorrhages caused by intracranial dissections are rare. The management of dissections in these cases not clear.

METHODS

Case report.

RESULTS

An 82-year-old woman presented with acute drowsiness and vomiting. CT scan demonstrated extensive subarachnoid hemorrhage and hydrocephalus that subsequently required placement of ventriculoperitoneal shunt. Angiography revealed extensive basilar artery dissection and no aneurysms. The dissection did not produce a critical stenosis and, taking into consideration that the patient had a previous occlusion of her distal left vertebral artery, it was decided to manage the patient conservatively. On a 3-month follow-up, the patient was free of recurrent events.

CONCLUSION

Basilar artery dissection can present with subarachnoid hemorrhage. No guidelines are available for management of basilar artery dissections and treatment should be tailored to the individual patient.

Ruptured pseudoaneurysm of the internal maxillary artery complicating CT-guided fine-needle aspiration in an irradiated, surgical bed

BACKGROUND

CT-guided fine-needle aspiration (FNA) is a safe procedure, but major complications can occur rarely. Pseudoaneurysm rupture in the head and neck region following CT-guided FNA is an emergency that can result in life-threatening hemorrhage. This case emphasizes the salient risk factors for pseudoaneurysm formation and rupture in the head and neck region following CT-guided FNA.

METHODS

A patient was seen with oral and facial hemorrhage as a result of a ruptured pseudoaneurysm 11 weeks following CT-guided FNA in a previously irradiated surgical bed.

RESULTS

The patient was treated with coil embolization in and around the pseudoaneurysm and discharged without any further complications.

CONCLUSIONS

Although CT-guided FNA is a safe and effective procedure, some patients may be at increased risk for rare but major complications. Caution should be used in proceeding with CT-guided FNA in an irradiated surgical bed of the head and neck.

Dissecting aneurysms involving both anterior cerebral artery and aorta

Non-traumatic intracranial dissecting aneurysm (IDA) has been recently reported with increasing frequency and is recognized as a possible cause of subarachnoid hemorrhage. However, the pathogenesis of this disease is still unclear. Cystic medial necrosis (CMN) is known to be a cause of aortic dissection, especially in Marfan's syndrome. Presented herein is the case of a 49-year-old man who had IDA of the right anterior cerebral artery and abdominal aortic dissection without Marfan's syndrome. Histological examination showed medial degenerative changes with the accumulation of acid mucopolysaccharides in various intra- and extracranial arteries. Coexistence of dissecting aneurysms in the anterior cerebral artery and aorta suggests the presence of underlying pathogenesis that is common to these two dissection processes.

Prediction of rebleeding from angiographic features in vertebral artery dissecting aneurysms

To identify patient characteristics and angiographic features that predict high risk for rebleeding in vertebral artery (VA) dissecting aneurysms. We analyzed 62 patients treated for subarachnoid hemorrhage (SAH) from VA dissecting aneurysms (male: female, 46:16; mean age, 51.7 +/- 8 years). Univariate and multivariate stepwise logistic regression analyses were performed to assess relationships between rebleeding rate and age, gender, history of hypertension, sidedness of the aneurysm, angiographic configuration, and location relative to the origin of the posterior inferior cerebellar artery (PICA). Rebleeding occurred in 22 patients (37%), mostly within 24 h. Patients without rebleeding had favorable outcomes, while patients with rebleeding showed higher mortality. Angiographic patterns with high rebleeding rates included "stenosis and dilation" (50%), and "lateral protrusion" (43%), contrasting with "dilation and stenosis" (20%) and other types. Rebleeding also was likely in aneurysms proximal to or at the PICA origin (rate, 47% or 46%) than distal to the PICA origin (21%). Multivariate logistic regression analysis found two factors independently associated with rebleeding: angiographic pattern of the aneurysm (odds ratio 1.88:1, P=0.0366), and location relative to the PICA origin (odds ratio 4.93:1, P=0.028). High risk of rebleeding in VA dissecting aneurysms can be predicted by angiographic configurations such as "stenosis and dilation" and "lateral protrusion" and by location at or proximal to the PICA origin.

Clinical analysis of vertebrobasilar dissection

BACKGROUND

The natural history of vertebrobasilar artery dissection (VAD) is not fully known. The purpose of this study was to review the clinical outcome of the patients with VAD, then to propose an appropriate management strategy for VAD.

METHOD

From 1992 to 2004, 35 VAD patients admitted to our institutes were retrospectively reviewed. There were 28 men and 7 women, whose age ranged from 4 to 67 years with a mean age of 44 years. Angiography was assessed to document the shape, and location of the dissecting aneurysm with respect to the posterior inferior cerebellar artery (PICA). A modified Rankin score was assigned for functional outcome. The functional outcome scores were analyzed according to the patient's age, gender, hypertension history, the pattern of initial manifestation, angiographic shape of VAD, angiographic location of VAD, treatment modality.

FINDINGS

There was no statistically significant difference between the functional outcome with age, gender, trauma history and past medical history of hypertension. Of 35 patients, 22 presented with SAH, 11 with ischemic symptoms and 2 were incidentally detected. The patients without SAH had a better functional outcome than those with SAH (p = 0.029). There was statistical significance between Hunt-Hess (H-H) grade and clinical outcome (p = 0.032). The shape and location of VAD was not significantly related to the functional outcome (p = 0.294, 0.840). But all the cases of rebleeding and mortality (except one case with initially poor H-H grade) developed exclusively in patients with aneurysms. There was no statistically significant correlation between the treatment modality and the outcome (p = 0.691).

CONCLUSION

The VAD patients with SAH would be recommended to be managed by either surgical or endovascular treatment, but those without SAH, could be managed conservatively with antiplatelet therapy and/or anticoagulation.

Atherosclerosis in the vertebral artery: an intrinsic risk factor in the use of spinal manipulation?

The presence of atherosclerotic plaques and their influence on the vertebral artery is of clinical importance within the scope of spinal manipulation. Manipulation may stimulate the development of atherosclerotic plaques, could detach an embolus with ensuing infarction, injure the endothelium or may directly cause a dissection in the presence of atherosclerotic plaques. In order to identify the sites and frequency of atherosclerotic plaques and to determine its relation to the tortuous course of the vertebral artery, a cadaveric study was performed. The vertebral arteries of 57 human cadavers were studied. The vertebral artery was virtually divided into four segments: the pre-vertebral (V1), the vertebral (V2), the atlanto-axial (V3), and the intracranial segment (V4). Abnormalities in the origin and course of the vertebral artery were noted, along with any associated osseous, or cartilaginous anomalies in the neck. After dissection, the artery was opened and macroscopically screened for the presence of atherosclerotic plaques. In 22.8% of the cases, no atherosclerotic plaques were present. In 35.1% of the cases, the atherosclerotic plaques were unilateral, of which 60.0% was on the left side, 40.0% on the right side, and in 42.1%, the occurrence was bilateral. Atherosclerotic plaques were significantly more present in the V3 segment than in the V1 (0.007) and V2 segment (0.049). In the V1 (P=0.008) and V2 segment (P=0.002), there was a correlation between a tortuous course of the vessel and the occurrence of atherosclerotic plaques. In individuals with marked atherosclerotic disease, stretching and compression effects of rotational manipulative techniques on atherosclerotic vessels impose a further risk factor for vertebrobasilar insufficiency. As direct evidence of atherosclerotic plaques are rarely available, therapists should avoid manipulative techniques at all levels of the cervical spine in the presence of any indirect sign of atherosclerotic disease or in the presence of calcified arterial walls or tortuosities of the vessels visible on routinely available X-ray images of the cervical or thoracic spine. It is strongly recommended, that if any doubt exists about the nature of a clinical presentation, vigorous manual procedures should be avoided until either the diagnosis is definitive or gentle manual therapy has proven effective.

Infarctus latéro-bulbaire sur dissection intracrânienne suivi d’une hémorragie sous-arachnoïdienne

INTRODUCTION

Intracranial vertebral artery dissecting aneurysms are a recognized cause of subarachnoid hemorrhage and the hemorrhagic recurrence risk after a first rupture of the dissecting aneurysm is high and of poor prognosis. However, when the dissection is discovered in a patient with vertebrobasilar territory ischemia, little is known about the risk of hemorrhagic rupture risk and there is no consensus on management.

OBSERVATION

We report the case of a 49-year-old man who developed subarachnoid hemorrhage 48 hours after the occurrence of a latero-bulbar syndrome caused by a spontaneous dissection with occlusion of the right vertebral artery. The subsequent angiography showed a V4 dissecting aneurysm of the right vertebral artery which was treated by stenting and coiling without any complications.

CONCLUSION

This case underlines the hemorrhagic risk of an intradural vertebral artery dissection and its possible progression to aneurysm. Subsequent angiographic imaging must be carefully examined to search for aneurysms which may require early specific treatment because of the high risk of recurrent bleeding.

A case of segmental mediolytic arteriopathy involving both intracranial and intraabdominal arteries

Segmental mediolytic arteriopathy (SMA) is an uncommon nonatherosclerotic and nonvasculitic arteriopathy. This disease is characterized by lytic degeneration of the arterial media, intramural dissection and thrombosed or ruptured aneurysm. SMA mainly involves the intraabdominal arterial system, resulting in intraabdominal and retroperitoneal hemorrhage. However, only a few cases of SMA with involvement of intracranial arteries have been reported. Here, we present a case of SMA developing subarachnoid hemorrhage due to dissection of the internal carotid and vertebral arteries. This patient was a 48-year-old male who died 13 days after admission for sudden loss of consciousness. Computed tomography showed subarachnoid hemorrhage. At autopsy, the affected vessels included the right vertebral, left internal carotid, superior mesenteric, bilateral renal and left external iliac arteries. Histopathologically, the arteries showed segmental lytic degeneration and disappearance of medial smooth muscle cells, medial dissection and formation of pseudo-aneurysms, the wall of which consisted of a thin membrane of the adventitia. These histopathological features mimicked an entire wall dissection type of intracranial dissecting aneurysm, which exclusively affects the vertebro-basilar system. Thus, SMA should be considered a possible underlying disease in patients with spontaneous dissection of intracranial arteries.

Vertebrobasilar artery dissection presenting with simultaneous subarachnoid hemorrhage and brain stem infarction: case report

BACKGROUND

Intracranial dissecting aneurysms have been associated with subarachnoid hemorrhage (SAH) or cerebral ischemia. We encountered a patient presenting with simultaneous subarachnoid hemorrhage and brainstem infarction caused by a dissecting aneurysm of the vertebrobasilar artery, which was diagnosed by magnetic resonance imaging (MRI) but did not show abnormal findings on cerebral angiography.

CASE DESCRIPTION

A 55-year-old man had sudden onset of headache and left abducens palsy. Computed tomography revealed a subarachnoid hemorrhage localized in the left prepontine cistern and the left cerebellomedullary fissure. Cerebral angiography showed neither a saccular aneurysm nor fusiform dilatation causing the subarachnoid hemorrhage. MRI demonstrated a small infarction in the left dorsal pons, and an intramural hematoma of the left vertebral artery and lower basilar artery.

CONCLUSION

This is a rare case of a vertebrobasilar dissecting aneurysm that simultaneously caused both SAH and brain stem infarction. MRI should be performed in the acute phase of SAH of unknown origin to determine the possible coexistence of a dissecting aneurysm, as occurred in this case.