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

Diagnosis and Treatment of Cerebral Aneurysm Associated with Segmental Arterial Mediolysis: Our Experience and Systematic Review

BACKGROUND

Segmental arterial mediolysis (SAM) is a nonatherosclerotic, noninflammatory vascular disease, initially reported in 1976 by Slavin and Gonzalez-Vitale. SAM-associated cerebral aneurysms have been reported in limited cases, and the disease entity is not fully understood. Therefore, we propose a diagnostic and treatment strategy with a systematic review of previously reported cases and our cases.

METHODS

We systematically searched cases of SAM-associated cerebral aneurysms using an online database. The findings of each included study and our cases were systematically reviewed in terms of characteristics, aneurysm, and clinical course.

RESULTS

In addition to our 2 cases, 41 cases from 32 publications were included. SAM-associated cerebral aneurysms were common among East Asians, particularly Japanese, aged 40-50 years, and typically presented as subarachnoid hemorrhage (SAH; 86%). Most aneurysms (75%) were dissection aneurysms. Subarachnoid hemorrhage (SAH) cases had a higher risk of successive intra-abdominal hemorrhage (IAH) caused by visceral aneurysm rupture (59%), with a mortality of 41%. It was most likely to occur 8.2 ± 7.3 days after SAH. If operations were accomplished, the prognosis was relatively good (modified Rankin Scale score 0-3; 71%).

CONCLUSIONS

SAM-associated cerebral aneurysms can be life-threatening because of the risk of rupture and can lead to successive IAH after SAH. However, the prognosis is relatively good if an operation is successful. Therefore, precise diagnosis is required for suspected cases at first, and appropriate surgical treatment is required. Moreover, appropriate management of successive IAH is required among patients with SAH.

Differentiating between segmental arterial mediolysis and other arterial vasculopathies to establish an early diagnosis - a systematic literature review and proposal of new diagnostic criteria

Segmental arterial mediolysis (SAM) is a rare vascular disease, characterized by acute but transient vulnerability of the wall of medium-sized arteries. The most characteristic feature of SAM is its biphasic course: an injurious phase marked by acute weakness of the arterial wall leading to acute dissection and/or hemorrhage, followed by a reparative phase in which granulation tissue and fibrosis restore the injured arterial wall. Residual stenosis, aneurysms, and/or arterial wall irregularities may remain visible on future imaging studies. Differentiating between SAM and other arterial vasculopathies is difficult due to its similarities with many other vascular diseases, such as vasculitis, fibromuscular dysplasia, inherited connective tissue disorders, and isolated visceral artery dissection. In this systematic review, we provide an overview on SAM, with an emphasis on the differential diagnosis and diagnostic work-up. We propose new diagnostic criteria to help establish a prompt diagnosis of SAM, illustrated by case examples from our multidisciplinary vascular clinic.

Superficial temporal artery aneurysm with segmental arterial mediolysis: a case report

Segmental arterial mediolysis (SAM) is a rare non-arteriosclerotic and non-inflammatory vascular disease. Superficial temporal artery (STA) aneurysms are usually associated with trauma, surgery, and hair transplantation. Spontaneous aneurysms of the STA are uncommon, but an STA aneurysm caused by SAM is rare. We report a 70-year-old woman with a spontaneous aneurysm of the STA. The mass in the left parietal region was pulsatile and gradually enlarged in size without any history of head trauma. The mass was successfully removed by surgery and was proved histopathologically to be a true aneurysm with SAM.

Intraperitoneal hemorrhage due to segmental arterial mediolysis associated with cerebral vasospasm after subarachnoid hemorrhage

A man in his 50s with no significant past medical history developed subarachnoid hemorrhage due to ruptured left middle cerebral artery aneurysm. On the ninth hospital day, he had a ruptured visceral aneurysm with segmental arterial mediolysis, and we successfully treated with transarterial embolization using metallic coils.

Intra-abdominal hemorrhage due to segmental arterial mediolysis of an ovarian artery pseudoaneurysm and concomitant aneurysmal subarachnoid hemorrhage: illustrative case

BACKGROUND

Aneurysmal subarachnoid hemorrhage (SAH) is one of the most severe neurosurgical diseases in which systemic management is important from the acute phase to the chronic phase. The authors reported a case of aneurysmal SAH associated with intra-abdominal hemorrhage possibly caused by segmental arterial mediolysis (SAM).

OBSERVATIONS

A 60-year-old woman collapsed suddenly at home. On arrival at our hospital, she was comatose and her head computed tomography (CT) showed SAH, probably from an anterior cerebral artery aneurysm. Simultaneous body CT to screen for pneumonia associated with COVID-19 incidentally detected an intra-abdominal hematoma and the bleeding point. Emergent ventriculostomy was conducted first. Because abdominal angiography detected a ruptured pseudoaneurysm of an ovarian artery, emergency embolization was subsequently performed for hemostasis. However, she deteriorated again, and her pupils became fully dilated. The patient died on day 3 of hospitalization.

LESSONS

Patients with aneurysmal SAH rarely have intra-abdominal hemorrhage in the acute stage and may have a fatal outcome. Intra-abdominal hemorrhage should be suspected in the setting of unstable vital signs, and prompt treatment is necessary.

A case of subarachnoid hemorrhage caused by multiple cerebral aneurysms due to segmental arterial mediolysis

Background:

Segmental arterial mediolysis (SAM) is a condition in which an aneurysm is formed by causing lysis of the media and remodeling of blood vessels. Short-term recurrence has been reported in abdominal aortic aneurysms. Cerebral aneurysms have been suggested to form in a short period not only in the abdominal cavity but also in the intracranial arteries in SAM.

Case Description:

A 36-year-old pregnant woman at 35 weeks’ gestation developed sudden headache and disorientation. Head magnetic resonance imaging showed a small amount of subarachnoid hemorrhage in the right ambient cistern. A fusiform cerebral aneurysm was found in the periphery of the right superior cerebellar artery, and small saccular aneurysms were found in the periphery of the right posterior cerebral artery and left posterior inferior cerebral artery. After delivery of the fetus, endovascular embolization of the ruptured aneurysm was performed. However, 10-week postoperatively, she developed sudden headache. Hemorrhage was found in the fourth ventricle, and enlargement of the left posterior inferior cerebellar artery (PICA) peripheral aneurysm and disappearance of the right posterior cerebral artery peripheral aneurysm were confirmed. A ruptured aneurysm in the peripheral left PICA was removed after trapping. Intraoperatively, an unruptured thrombosed aneurysm that was not visualized by imaging was also removed. Histopathological examination showed no calcification or inflammation, rupture of the internal elastic lamina, and lack of segmentation, and SAM was diagnosed.

Conclusion:

In atypical dissecting aneurysms, SAM should be considered as a differential diagnosis. Systemic examination and short-term follow-up are also necessary.

Fatal hemorrhage after tonsillectomy

This is the first report of a segmental mediolysis occurring in arterioles, affecting the neck/tonsillar region and leading to a fatal hemorrhage after a tonsillectomy in a 20-year-old woman. Arteriolar mediolysis could be observed in tissue layers about 2 cm distant from the tonsillectomy region. Reparative changes were observed in the carotid and small neck arteries as well as in only one intramyocardial arteriole; however, no other vascular regions typically reported in segmental mediolysis arteriopathy were affected and aneurysm formation was not observed. No family history of vascular disease or hypertension was known. Pathophysiologically, previously reported reasons for post-tonsillectomy bleeding could be excluded. Segmental mediolysis may represent a wider spectrum of affected arteriolar vessels besides the reported small and medium sized arteries leading to aneurysms, which impedes radiographic diagnosis.

A Ruptured Blood Blister-Like Aneurysm Associated with Intraperitoneal Hemorrhage due to Segmental Arterial Mediolysis: A Case Report and Literature Review

BACKGROUND

Segmental arterial mediolysis (SAM) is a rare non-atherosclerotic, noninflammatory vascular disease, characterized by mediolysis. We report an extremely rare case of subarachnoid hemorrhage (SAH) due to a ruptured blood blister-like aneurysm (BBA) of the internal carotid artery associated with SAM-related arteriopathy.

CASE DESCRIPTION

We experienced a case of SAH followed by intraperitoneal hemorrhage that occurred 12 days after the SAH onset. SAH was caused by a ruptured BBA of the internal carotid artery, which was treated by trapping with high-flow bypass. Intraperitoneal hemorrhage was caused by a rupture of a posterior inferior pancreaticoduodenal artery (PIPDA) aneurysm, which induced hypovolemic shock resulting in death in spite of endovascular internal trapping. Postmortem pathologic examination revealed that the PIPDA pseudoaneurysm was due to SAM.

CONCLUSIONS

We should pay attention to the association of SAM, which is a potentially life-threatening pathology when treating cerebral BBAs.

Unexpected intraabdominal hemorrhage due to segmental arterial mediolysis following subarachnoid hemorrhage: A case of ruptured intracranial and intraabdominal aneurysms

Background:

Segmental arterial mediolysis (SAM) is an uncommon vascular disease, which manifests as catastrophic intraabdominal hemorrhage caused by rupture of visceral dissecting aneurysms in most cases. The etiology of SAM is still unclear, but SAM may be a vasospastic disorder and the responsible pressor agent is norepinephrine. Recently, abdominal SAM coexisting with intracranial dissecting aneurysms has been reported, but the relationship between intraabdominal and intracranial aneurysms in SAM remains unclear, as no cases of concomitant abdominal SAM and ruptured intracranial saccular aneurysm have been reported.

Case Description:

A 49-year-old woman underwent emergent clipping for a ruptured saccular aneurysm at the left C1 portion of the internal carotid artery. Intraoperatively, norepinephrine was continuously administered intravenously under general anesthesia. Four days after the subarachnoid hemorrhage (SAH), the patient suddenly developed shock due to massive hematoma in the abdominal cavity. Imaging showed multiple aneurysms involving the splenic artery, gastroduodenal artery, common hepatic artery, and superior mesenteric artery. Coil embolization of the splenic artery was performed immediately to prevent bleeding. Subsequent treatment for cerebral vasospasm following SAH was performed with prevention of hypertension, and the patient recovered with left temporal lobe infarction. The diagnosis was abdominal SAM based on the clinical, imaging, and laboratory findings.

Conclusion:

Norepinephrine release induced by SAH and/or iatrogenic administration of norepinephrine may have promoted abdominal SAM in this case. Abdominal SAM may occur subsequent to rupture of ordinary saccular aneurysm, and may provoke catastrophic abdominal hemorrhage in the spasm stage after SAH.

Subarachnoid and intraperitoneal hemorrhage secondary to segmental arterial mediolysis: A case report and review of the literature

Background Segmental arterial mediolysis (SAM) is an uncommon or underdiagnosed arteriopathy that presents with life-threatening hemorrhage. SAM can affect the intracranial, spinal, and visceral arteries, with reported cases of concomitant intracranial and visceral hemorrhage. Case description We present the case of a 61-year-old male with concurrent subarachnoid and intraperitoneal hemorrhage caused by simultaneously bleeding posterior spinal artery and splenic artery pseudoaneurysms. The posterior spinal artery pseudoaneurysms were treated with selective injection of polyvinyl alcohol particles into the posterior spinal artery, while the splenic artery pseudoaneurysm was treated with Gelfoam embolization. The constellation of imaging, clinical, and laboratory features led to a presumptive diagnosis of SAM, which remains the only reported cause of concurrent neurovascular and visceral artery aneurysm rupture. Conclusion SAM is a key diagnostic consideration in cases of concomitant intracranial, spinal, and visceral artery aneurysm rupture.

Fatal hemoperitoneum due to segmental arterial mediolysis

Spontaneous hemoperitoneum due to vascular injury is a life-threatening condition mostly associated with aortic or splanchnic arterial disease, which stems from atherosclerotic, inflammatory, or infectious origin. However, in 1976, Slavin and Gonzales described a nonatherosclerotic arterial disease that may render aneurysmal formation predominantly in the splanchnic arterial bed. The clinical presentation is diverse, but abdominal pain and shock prevail. We report the case of a middle-aged man who presented a hemoperitoneum due to a middle colic artery aneurysm rupture and died after undergoing a surgical treatment attempt. The preoperative imaging study revealed the presence of a huge hematoma in the epiplon retrocavity, and abdominal free liquid as well as extensive arterial disease with multiple aneurysms. The autopsy findings included hemoperitoneum, hematoma in the upper left abdominal quadrant, the surgical ligature of the middle colic artery, and histologic features consistent with segmental arterial mediolysis. The authors call attention to this rare entity and highlight the autopsy as a fundamental examination to accurately reach this diagnosis.

A pregnancy-associated nonfamilial case of PAPA (pyogenic sterile arthritis, pyoderma gangrenosum, acne) syndrome

Little is known about the influence of pregnancy on pyogenic sterile arthritis, pyoderma gangrenosum, acne (PAPA) syndrome. We experienced a rare case of pregnancy complicated with PAPA syndrome. The patient had various histories of skin and joint disorders and experienced subarachnoid hemorrhage during pregnancy; however, her skin lesion was unaffected.

Longitudinal Evaluation of Segmental Arterial Mediolysis in Splanchnic Arteries: Case Series and Systematic Review

BACKGROUND

Segmental arterial mediolysis (SAM) is a rare non-atherosclerotic, non-inflammatory vascular disorder varying widely in clinical course. The purpose of this study is to analyze detailing clinical and imaging manifestations over time in patients with SAM through a literature review and to suggest an optimal management strategy.

METHODS

A retrospective review of eight consecutive patients diagnosed with SAM between January, 2000 and January, 2012 was conducted. All presented with acute-onset abdominal or flank pain. Clinical features, imaging studies, and laboratory findings served as grounds for diagnosis, having excluded more common conditions (ie, fibromuscular dysplasia, collagen vascular disorders, or arteritis). CT angiography was done initially and repeated periodically (Week 1, Month 3, then yearly). Treatment was conservative, utilizing endovascular intervention as warranted by CT diagnostics. In a related systematic review, all English literature from 1976 to 2015 was screened via the PubMed database, assessing patient demographics, affected arteries, clinical presentations, and treatment methods.

FINDINGS

Ultimately, 25 arterial lesions identified in eight patients (median age, 62.8 years; range, 40-84 years) were monitored for a median period of 26 months (range, 15-57 months). At baseline, celiac axis (3/8, 37.5%), superior mesenteric (4/8, 50%), and common hepatic (2/8, 25%) arteries were involved, in addition to isolated lesions of right renal, splenic, right colic, middle colic, gastroduodenal, left gastric, right gastroepiploic, proper hepatic, right hepatic, and left hepatic arteries. Compared with prior publications, celiac axis and superior mesenteric artery were more commonly affected in cohort. Arterial dissections (n = 8), aneurysms (n = 5), stenoses or occlusions (n = 4), and a single pseudoaneurysm were documented. Despite careful conservative management, new splanchnic arterial lesions (n = 4) arose during follow-up. Considering the few available reports of new arterial lesions in the literature, newly developing pathology is a distinctive feature of our patients, four of whom eventually required endovascular interventions.

CONCLUSIONS

Careful clinical observation via periodic CT angiography is required in patients with SAM, checking for newly developing lesions. The natural history of SAM should be clarified in a larger patient population.

Segmental Arterial Mediolysis Involving Both Vertebral and Middle Colic Arteries Leading to Subarachnoid and Intraperitoneal Hemorrhage

BACKGROUND

Segmental arterial mediolysis (SAM) is not yet well known in the neurosurgical field, even though it has become an increasingly recognized pathology in arterial dissection.

CASE DESCRIPTION

A case of SAM presented as subarachnoid hemorrhage (SAH) due to a dissecting aneurysm of the left intracranial vertebral artery (VA), which extended from the proximal VA union to the distal portion of the left posterior inferior cerebellar artery. The lesion was successfully embolized by an endovascular technique. However, subsequent intraperitoneal hemorrhage due to rupture of a fusiform aneurysm of the middle colic artery prompted surgical treatments. The features of the extirpated visceral vascular lesion were compatible with the diagnosis of SAM based on histopathologic examinations.

CONCLUSIONS

It is very important that SAM is recognized as a systemic disease that affects the central nervous system, visceral arteries, and coronary arteries. The possibility of SAM should always be considered, particularly in patients with ruptured VA dissection-which is nowadays treated by endovascular techniques-since concomitantly involved visceral arteries may cause unexpected hemorrhagic complications other than SAH.

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.

Arterial distensibility in patients with ruptured and unruptured intracranial aneurysms: is it a predisposing factor for rupture risk?

Background

A risk factor assessment that reliably predicts whether patients are predisposed to intracranial aneurysm (IA) rupture has yet to be formulated. As such, the clinical management of unruptured IA remains unclear. Our aim was to determine whether impaired arterial distensibility and hypertrophic remodeling might be indicators of risk for IA rupture.

Material/Methods

The study population (n=49) was selected from consecutive admissions for either unruptured IA (n=23) or ruptured IA (n=26) from January to December 2010. Hemodynamic measures were taken from every patient, including systolic and diastolic blood pressure using a sphygmomanometer. Unruptured IA and ruptured IA characteristics, including aneurysmal shape, size, angle, aspect ratio, and bottleneck factor, were measured and calculated from transverse brain CT angiography images. With ultrasound, the right common carotid artery intima-media thickness was measured, as well as the lumen diameter during systole and diastole. Arterial wall strain, distensibility, stiffness index, and elastic modulus were calculated and compared between patients with unruptured IAs and ruptured IAs. A p-value less than 0.05 was considered statistically significant.

Results

General demographic data did not differ between patients with unruptured IAs and ruptured IAs. Greater mean intima-media thickness (p=0.013), mean stiffness index (p=0.044), and mean elastic modulus (p=0.026) were observed for patients with ruptured IAs. Moreover, mean strain (p=0.013) and mean distensibility (p=0.024) were decreased in patients with ruptured IAs.

Conclusions

Patients with ruptured IAs demonstrated decreased arterial distensibility and increased intima-media thickness at the level of the carotid arteries. By measuring these parameters via ultrasound, it may be possible to predict whether patients with existing IAs might rupture and hemorrhage into the subarachnoid space.

Segmental arterial mediolysis: a systematic review of 85 cases

BACKGROUND

Segmental arterial mediolysis (SAM) is a nonatherosclerotic, noninflammatory arteriopathy of unknown etiology with life-threatening manifestations. With advances in endovascular techniques, SAM is increasingly being managed without the need for major surgery.

METHODS

A systematic review of the literature published on SAM between 1976 and 2012 was performed, focusing on arterial involvement, diagnostic imaging modalities, mortality and morbidity rates, and in particular treatment outcomes with open versus endovascular intervention.

RESULTS

Sixty-two studies reporting on 85 cases of SAM were reviewed. Sixty-nine percent of cases were diagnosed histologically (24% on autopsy). Angiography was the most common form of diagnostic imaging modality (56% of cases). Arterial involvement was largely abdominal or cranial, with splenic arterial involvement being the most prevalent (29% of cases). There was a total SAM-related mortality of 26%. Endovascular intervention, most commonly in the form of coil embolization of aneurysmal vessel(s), was successful in 88% of cases where attempted, with no reported mortality. There was a mortality rate of 9% where open surgery was attempted.

CONCLUSIONS

Catheter-based endovascular techniques can be a successful, minimally invasive treatment option in the management of this potentially life-threatening condition, and may also provide a temporary bailout measure in the acute phase before definitive surgical treatment at a later stage.

Putamen hemorrhage occurred simultaneously with Stanford type A acute aortic dissection: a case report

This case report describes a 60-year-old man found unresponsive on the road. He was later admitted to our emergency department (ED) with consciousness disturbance and decorticate rigidity. Computed tomographic imaging revealed coexisting left putamen hemorrhage and Stanford type A acute aortic dissection. Decompressive craniectomy and hematoma evacuation were performed, but he died during his second hospital day. Morbid anatomy proved aortic dissection from the ascending aorta to left common iliac artery with pericardial effusion up to 500 mL. Brain hemorrhage and acute aortic dissection share several risk factors including hypertension and atherosclerosis, but few cases have been reported with brain hemorrhage and aortic dissection occurring simultaneously. Diagnosis for aortic dissection is difficult, especially when the patient has consciousness disturbance because of brain hemorrhage. Consequently, coexistence of these 2 conditions might be missed frequently in emergency settings. Therefore, wider knowledge of this case is important to inform others to suspect and investigate aortic dissection in cases of brain hemorrhage.

Pathomorphometry of ruptured intracranial vertebral arterial dissection: adventitial rupture, dilated lesion, intimal tear, and medial defect

OBJECT

Subarachnoid hemorrhage (SAH) due to ruptured intracranial vertebral artery (VA) dissection is a life-threatening disease. Angiographic and symptomatic prognostic factors for rupture and rerupture have been investigated, but the pathological characteristics have not been fully investigated. The authors aimed to investigate these features by performing a pathomorphometic study of ruptured intracranial VA dissections.

METHODS

This study included 50 administrative autopsy cases of fatal SAH due to ruptured intracranial VA dissection among 517 fatal nontraumatic cases of SAH occurring between March 2003 and May 2011. Pathomorphometry was performed using serial 5-μm histological cross-sections with elastica van Gieson staining from each 0.2-mm segment around the ruptured intracranial VA. The longitudinal lengths of 4 types of vascular lesions-adventitial ruptures, dilated lesions where the internal elastic lamina (IEL) was ruptured with adventitial extension, intimal tears where the IEL was ruptured, and medial defects-were calculated based on the numbers of the slides in which these lesions were continuously detected (minimum 2 adjoining slides). The distance from the vertebrobasilar junction to the center of adventitial rupture was also calculated in 37 cases.

RESULTS

All cases showed one adventitial rupture with a mean length of about 1.9±1.1 mm. The center of the adventitial rupture was located 5.0-26.8 mm (mean 14.6±5.5 mm) from the intracranial VA bifurcation. Adventitial ruptures existed in the centers of dilated lesions, where the adventitia was highly extended. Other vascular lesions were serially observed surrounding the adventitial rupture. The mean lengths of dilated lesions, intimal tears, and medial defects were 9.4±4.8 mm, 13.2±6.3 mm, and 15.6±7.2 mm, respectively. The lengths between proximal lesions and distal lesions from the center of the adventitial rupture for both medial defects and intimal tears were significantly longer at proximal lesions than at distal ones (chi-square test, p<0.01).

CONCLUSIONS

Every ruptured intracranial VA dissection has a single point of adventitial rupture where the adventitia was maximally extended, so dilation appears to be a valuable predictive factor for hemorrhagic intracranial VA dissections. The adventitial ruptures were as small as 2 mm in length, and clinically detectable dilated lesions were about 9 mm in length. However, vascular vulnerability caused by IEL ruptures and medial defects existed more widely across a length of VA of 1.3-1.5 cm. Comparatively broader protection of the intracranial VA than the clinically detected area of dissection might be desirable to prevent rebleeding. Broader protection of proximal lesions than distal lesions might be effective from the viewpoint of site distribution of vascular lesions and blood flow alteration to the pseudolumen caused by the dissecting hematoma. Medial defects are the most widely seen lesions among the 4 types of vascular lesions studied. Medial degenerative disease, known as segmental arterial mediolysis, is suspected in the pathogenesis of intracranial VA dissections.

Subarachnoid hemorrhage in a case of segmental arterial mediolysis with coexisting intracranial and intraabdominal aneurysms

The authors report the rare case of a 58-year-old man with segmental arterial mediolysis (SAM) with associated intracranial and intraabdominal aneurysms, who suffered subarachnoid hemorrhage (SAH) due to rupture of an intracranial aneurysm. This disease primarily involves the intraabdominal arterial system, resulting in intraabdominal and retroperitoneal hemorrhage in most cases. The patient presented with severe headache and vomiting. The CT scans of the head revealed SAH. Cerebral angiography revealed 3 aneurysms: 1 in the right distal anterior cerebral artery (ACA), 1 in the distal portion of the A1 segment of the right ACA, and 1 in the left vertebral artery. The patient had a history of multiple intraabdominal aneurysms involving the splenic, gastroepiploic, gastroduodenal, and bilateral renal arteries. He underwent a right frontotemporal craniotomy and fibrin coating of the dissecting aneurysm in the distal portion of the A1 segment of the right ACA, which was the cause of the hemorrhage. Follow-up revealed no significant changes in the residual intracranial and intraabdominal aneurysms. An SAH due to SAM with associated multiple intraabdominal aneurysms is extremely rare. The authors describe their particular case and review the literature pertaining to SAM with associated intracranial and intraabdominal aneurysms.

Segmental arterial mediolysis: report of 2 cases and review of the literature

Segmental arterial mediolysis (SAM) is an idiopathic noninflammatory vasculopathy involving small to medium arteries, usually in the abdomen, although arteries in the cerebral and coronary circulations also may be affected. Some cases present as abdominal apoplexy due to aneurysmal rupture, but ischemia and infarction also occur. Not uncommonly, SAM may be misdiagnosed as a systemic necrotizing vasculitis. We present 2 patients with bilateral renal infarctions, cerebral arterial dissections, and visceral artery microaneurysms. Both were diagnosed initially as polyarteritis nodosa. The diagnosis was changed to SAM, in one case based on clinical and radiologic features, and in the other, on an open wedge kidney biopsy. We discuss the differential diagnosis and review the literature on SAM.

[Segmental arterial mediolysis and renovascular hypertension]

Segmental arterial mediolysis (SAM) is a rare nonarteriosclerotic, noninflammatory vascular disease of unknown origin that causes vascular occlusion or massive life-threatening intraabdominal hemorrhages. SAM is an acute disease. The initial injurious phase consist in mediolysis, then evolves in chronic vascular lesions. Diagnostic criteria are histologic, but rarely accessible apart from surgical complications. To our knowledge, there is no recommendation concerning therapy and follow-up of these patients. In our patient, we were interested in the atypical clinical presentation with renovascular hypertension, and the coexistence of acute and chronic vascular lesions that suppose the existence of recurrences in the evolution of this disease. We are interested also in the link that might exist between renal infarct and SAM, SAM's chronic vascular lesions and fibromuscular dysplasia vascular lesions.

Aneurysms of the renal arteries associated with segmental arterial mediolysis in a case of polyarteritis nodosa

This is the first report of segmental arterial mediolysis (SAM) accompanied with polyarteritis nodosa (PN), and manifesting aneurysms of the renal arteries. A 73-year-old woman was admitted to hospital because of a high fever. Laboratory tests showed leukocytosis with increased CRP level in the serum. Myeloperoxidase-anti-neutrophil cytoplasmic antibody (MPO-ANCA) and proteinase 3 (PR3)-ANCA were negative. There were no signs indicating infection or malignancy. After admission renal function rapidly deteriorated. Treatment was then started with daily oral prednisolone and hemodialysis. On the 40th day of hospitalization the patient suddenly became comatose. Cranial CT showed a subarachnoid hemorrhage. The patient died and an autopsy was performed. The pathological findings showed necrotizing vasculitis of the small arteries in various organs, but not associated with that of arterioles or renal glomerular lesions, indicating PN. Unexpectedly, the segmental arteries of the bilateral kidneys showed vascular lesions of dissecting aneurysms, indicating SAM. This case indicates that SAM is one of the causes of aneurysms in PN and is clinically important when the clinical course of PN patients rapidly advances.

Spontaneous bilateral carotid and vertebral artery dissections associated with multiple disparate intracranial aneurysms, subarachnoid hemorrhage and spontaneous resolution. Case report and literature review

Spontaneous bilateral carotid and vertebral artery dissections (CADs and VADs) are rare. A 29-year-old female presented with a collapse, 4 weeks after a sudden onset of severe neck and shoulder pain. CT scan revealed diffuse subarachnoid hemorrhage (SAH) and early hydrocephalus. Angiography revealed bilateral CADs and VADs, along with multiple fusiform and saccular aneurysms. Systemic vessels - including the renal arteries - were normal, and no risk factors or underlying vasculopathy were apparent. The presumed source of SAH (a posterior cerebral artery aneurysm) was successfully clipped. Each dissection, by contrast, was managed conservatively with heparin prophylaxis; and spontaneous CAD and VAD resolution occurred within 6 months. We present a unique case of four-vessel dissection associated with multiple disparate saccular and fusiform aneurysms. We suspect that underlying vasculopathy - perhaps novel - may become apparent with time.

Segmental arterial mediolysis with accompanying venous angiopathy: a clinical pathologic review, report of 3 new cases, and comments on the role of endothelin-1 in its pathogenesis

The authors review 20 cases of segmental arterial mediolysis (SAM) including 3 newly reported cases. SAM developed in areas of vascular distention in 2 of the latter cases: 1 in utero in the heart of a recipient of a twin transfusion syndrome and the other in the jejunum secondary to partial venous obstruction. In the third case, it occurred in a patient with Raynaud disease. Characterizing SAM are injurious and reparative lesions that occur in the media and/or at the adventitial medial junction. Four distinctive alterations are recognized: (1) mediolysis, (2) a tearing separation of the outer media from adventitia, (3) arterial gaps, and (4) a florid reparative response that replaces zones of mediolysis and fills areas of medial adventitial separation. The repair can transform SAM into lesions indistinguishable from common types of fibromuscular dysplasia (FMD.) A venous angiopathy involving large and medium-sized veins accompanies SAM. It features medial muscle vacuolar change with lysis leading to apparent separation of residual muscle bundles. Immunostaining shows endothelin-1 (ET-1) decorating adventitial capillaries in SAM and neighboring arteries, in capillaries of adjoining tissues, and outlining smooth muscle cell membranes in adjacent veins including those of the venous angiopathy. The significance of these changes is uncertain. Vasospasm is believed to cause SAM, but ET-1 is not the direct pressor agent responsible for this condition. The reason(s) for synthesis and release of ET-1 in SAM are still hypothetical, but local perturbations in vascular tone may be an important factor. ET-1 may be indirectly play a role in SAM by cross-talking and potentiating the activities of other vasoconstrictors such as norepinephrine and by orchestrating its reparative phase.

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.

Reconstructive surgery for segmental arterial mediolysis involving both the internal carotid artery and visceral arteries

Segmental arterial mediolysis (SAM) is a rare, nonatherosclerotic, noninflammatory arteriopathy. A 52-year-old man with sudden hemiparesis of the right side was found to have an aneurysm of the left internal carotid artery and concomitant multiple aneurysms of the extrahepatic, celiac, and superior mesenteric arteries. Reconstructive operations using autologous vein graft were performed to treat the aneurysms. The histopathology analyses of resected arterial and aneurysmal specimens showed characteristics consistent with SAM. To our knowledge, a successfully treated case of SAM affecting both the carotid artery and visceral arteries has not previously been described.

Segmental mediolytic arteriopathy in a patient with intraperitoneal bleeding

Segmental mediolytic arteriopathy (SMA) is a rare condition. It was first defined in 1976 and has been well described in the literature, although to date the aetiology of the condition is unknown. In most case reports SMA is diagnosed retrospectively once tissue has undergone histological examination. We present the first known case of SMA of the colic, mid-jejunal, common hepatic, intrahepatic and gastric arteries to be diagnosed at angiography after multiple episodes of undiagnosed intraperitoneal bleeding, and, perhaps related to this, one of the few reported patients with SMA involving multiple intra-abdominal arteries to have survived.

Bilateral extensive cerebral infarction and mesenteric ischemia associated with segmental arterial mediolysis in two young women

Segmental arterial mediolysis (SAM) is a rare non-atherosclerotic non-inflammatory vascular disease that affects mainly muscular arteries of the splanchnic and cerebral territories. Reported herein are two cases of SAM in young women with fatal outcome. One of the patients had an atypical form of the disease, which primarily affected small intestinal submucosal and subserosal arteries, and resulted in acute mesenteric ischemia. The other had bilateral brain infarction with SAM of internal carotid arteries (ICA). Pathological examination of both cases did not reveal the cause of blood flow disturbance: large mesenteric branches of the former and ICA of the latter were free of either dissection or thrombosis; in addition, small intestinal arteries of the first patient did not show signs of vasculitis. These findings suggest that unusual pathways of arterial occlusion and dissection may occur in the context of SAM.

Pseudovasculitis and corticosteroid therapy

Pseudovasculitis, vasculitis-like syndromes, vasculitis look-alikes, or mimics of vasculitis represent a heterogeneous collection of disorders that are capable of simulating vasculitis. Inappropriate diagnosis leads to delay or absence of proper management and exposure to potentially deleterious treatment modalities such as corticosteroids and cytotoxic agents. We report the case of fibromuscular dysplasia suspected to be a polyarteritis nodosa. The progression of the lesions visualized by the ultrasonographic study and computed tomography (CT) scan after 10 days of treatment led to an emergency laparotomy. The possible deleterious role of steroids given to treat the suspected vasculitis is discussed.

Deciding the cause of death after autopsy – revisited

One of the most difficult tasks in forensic medicine is deciding the cause of death in an unclear or debatable case. Most decision-making difficulties arise when there is a definite or potential causal interaction between: disease, injury, and circumstantial events. Sometimes these interactions are trivial, but in many instances the causal interaction is undeniably important, potentially important, or of uncertain relevance. In some cases, the cause of death may be unascertainable despite best efforts, and the pathologist must resist attempts at a presumptive, but objectively un-substantiated diagnosis. In general, there are three major categories that lead to difficulties: (i) co-existence of a pre-existing condition and a fatal injury; (ii) competing potential causes of death; (iii) historical events may be causally relevant to death by injury. In this review, these categories are discussed in detail and illustrated with relevant examples.

Spontaneous Multiple Arterial Dissections Presenting With Renal Infarction and Subarachnoid Hemorrhage in a Patient Under Treatment for Infertility

A 36-year-old woman developed multiple spontaneous arterial dissections in both renal arteries, the carotid artery, superior mesenteric artery, and vertebral artery, but not the aorta, and she suffered a renal infarction and subarachnoid hemorrhage within a short period of time. She had been undergoing frequent injections of human chorionic gonadotropin and human menopausal gonadotropin, together with oral estrogen therapy, during a 5-year infertility treatment regimen. As she had no other history of any disorder affecting the arterial walls, this therapy is suspected to have caused the multiple arterial deformities. Although cases of isolated arterial dissection are occasionally reported, it is rare for multiple dissections and serious symptoms to occur simultaneously.

Coexistence of cystic medial necrosis and segmental arterial mediolysis in a patient with aneurysms of the abdominal aorta and the iliac artery

Segmental arterial mediolysis is an unusual arterial lesion for which pathogenesis has remained controversial. We report on a 47-year-old Japanese woman who underwent surgery for an abdominal aortic aneurysm that was 10.5 cm in diameter and contiguous with a left common iliac aneurysm that was 2.3 cm in diameter; the aneurysms were considered to have progressed rapidly in size. Pathologic examinations of the respective aneurysms showed cystic medial necrosis in the aortic and segmental arterial mediolysis in the iliac aneurysm. Coexistence of these two pathologic findings indicates that there may be a strong relation between these two disease entities.