Pathogenesis of mycotic aneurysm

Unique clinical entity: Infective endocarditis with ruptured MCA mycotic aneurysm presented as fever of unknown origin: Case report and literature review

INTRODUCTION AND IMPORTANCE

Fever of unknown origin (FUO) in children poses a complex challenge for doctors. It involves a broad spectrum of potential diagnoses, with infectious diseases being the predominant culprits, followed by connective tissue disorders and malignancies.

CASE PRESENTATION

A 4-year-old boy with a prior diagnosis of a congenital bicuspid aortic valve was admitted to our hospital after experiencing two months of intermittent high-grade fever, severe nighttime headaches, and episodes of nausea and vomiting. His condition deteriorated rapidly with a drop in hemoglobin, elevated inflammatory markers, and the discovery of a large intracerebral hematoma. Further evaluation revealed infective endocarditis and a ruptured cerebral mycotic aneurysm associated with the bicuspid aortic valve infection. The aneurysm was successfully treated through cerebral endovascular catheterization, and the patient received six weeks of intravenous antibiotics. Cardiac surgery for valve repair was planned for a later date.

CLINICAL DISCUSSION

Among the infectious causes, infective endocarditis (IE) is a notable contributor, accounting for 1-5 % of all FUO cases. IE can lead to severe complications, with a small fraction of patients experiencing neurological issues such as stroke, encephalopathy, or the development of cerebral mycotic aneurysms.

CONCLUSION

The presented case serves as a stark reminder that FUO can be caused by serious underlying conditions, such as infective endocarditis. The rapid progression from fever and neurological symptoms to a ruptured cerebral mycotic aneurysm highlights the potentially life-threatening nature of these cases.

Diagnosis and treatment of mycotic aneurysms secondary to cardiac hydatid cyst: An unusual cause of multiple cerebral strokes in a 23-year-old female

Mycotic aneurysms (MA) are a rare but severe complication of systemic infections, carrying a high risk of rupture, hemorrhage, sepsis, and potential multiple organ failure. Intracranial arteries are often affected and present a significant mortality risk due to cerebral bleeding and ischemic strokes. In this paper we describe the case of a 23-year-old female patient who presented with a sudden onset of right hemiparesis, followed by loss of consciousness. Cerebral imaging revealed multiple infarcts in both hemispheres and intracranial hemorrhage secondary to ruptured pseudoaneurysms. On transthoracic echocardiogram, she was found to have a left ventricular cardiac cyst with mobile vegetations potentially responsible for mycotic aneurysms and cerebral strokes. The patient underwent endovascular embolization for the mycotic aneurysms and cardiac surgery for the left ventricular cyst with satisfying clinical outcomes. Postsurgical analysis revealed the cyst to be of hydatid (Echinococcus) origin.

Cerebral Myxomatous Aneurysms: Case Series and Systematic Review of Literature with Adequate Follow-Up Periods and Aneurysmal Wall Biopsy Results

BACKGROUND

Cerebral myxomatous aneurysms (CMA) are intracranial aneurysms caused by cardiac myxoma. The exact mechanism underlying their development has not yet been elucidated. And an optimal treatment method has not yet been established because of rarity of the disease. In addition, most existing reports have had a short follow-up period or lack of follow-up imaging test results. The aim of this study was to provide better insights into the course and treatment options of CMAs.

METHODS

We describe 4 CMA patients treated in our hospital and literature search was performed using PubMed and Embase databases. Keywords used were as follows: "cerebral myxomatous aneurysm", "myxomatous aneurysm", "cardiac myxoma", and "intracranial aneurysm". Only publications in English and related to this disorder with adequate follow-up periods and aneurysmal wall biopsy results were included. Clinical, radiological, pathological, and treatment characteristics were analyzed.

RESULTS

A total of 149 CMA cases were managed conservatively that included 9 enlargements, 6 regressions, and 134 stable aneurysms, which were identified for a total of 453.33 aneurysm years (1.91% per aneurysm year, 1.27% per aneurysm year, and 28.76% per aneurysm year, respectively). Poor outcome rate was high in cases with hemorrhage (either parenchymal or subarachnoidal hemorrhage) due to rupture of the CMA (46.67%, 7 out of 15). Thirteen cases had aneurysm biopsy results of which 11 showed tumor invasion on the aneurysm wall.

CONCLUSIONS

Even though the natural course of unruptured, benign-looking CMAs appears to be favorable, the presence or absence of viable tumor cells in the aneurysm may promote an unfavorable disease course. In the case of large, symptomatic, and enlarging CMAs, surgical, endovascular, or combined treatment should be considered as the mortality and morbidity due to rupture might be high.

Successful Endovascular Repair of Infectious External Iliac Artery Anastomotic Pseudoaneurysm With Graft Preservation Post-Kidney Transplantation: Case Report and Review of Literature

BACKGROUND

Allograft artery-infected pseudoaneurysm (PA) represents a rare but life-threatening complication of kidney transplantation (KT). A review of the literature, showed that nearly all these cases ended resulted in graft loss. We presented a case of post-KT-infected external iliac artery anastomotic PA successfully managed by endovascular stenting with graft preservation. Additionally, we reviewed the pertinent literature.

METHOD

In this article, we described a hypertensive, 47-year-old man who presented 1 month post-cadaveric KT with acute kidney injury and gram-negative bacteremia secondary to a large infectious anastomotic PA of the external iliac artery.

RESULTS

Because of favorable anatomy, successful arterial angio-stent fixation of the main renal artery PA, sparing the lower polar artery, was performed after 1 week of antibiotic and fungal coverage.

CONCLUSION

Patient was discharged after 2 weeks with functioning graft. Graft function was stable after 3 months.

Case report: Meningitis and intracranial aneurysm caused by mixed infection of oral microflora dominated by anaerobes

Introduction

Meningitis caused by oral anaerobic bacteria is rare, especially when complicated with an infected intracranial aneurysm. This paper has described an extremely rare case of bacterial meningitis caused by a mixed infection of oral microflora dominated by anaerobes, which developed cerebral infarcts, brain abscess, intracranial aneurysm, and severe hydrocephalus during treatment.

Case report

We describe a 65-year-old male patient who was presented with fever and headache as the initial symptoms and then developed left ophthalmoplegia, right hemiplegia, and disturbance of consciousness. Brain imaging showed that intracranial lesions were increased progressively, and cerebral infarcts, brain abscesses, intracranial aneurysm, and severe hydrocephalus were appeared gradually. Eventually, we diagnosed it as anaerobic meningitis by making deoxyribonucleic acid sequencing from the brain abscess pus. After using an anti-microbial regimen that can sufficiently cover anaerobes, the patient's condition was effectively controlled.

Conclusion

Anaerobic meningitis can cause a series of intracranial complications. Among them, the intracranial aneurysm is extremely rare. When evidence shows that the infection originates from oral flora, physicians should consider the possibility of this type of encephalitis. An early diagnosis and timely treatment are crucial to improving the prognosis.

Mycotic (Infected) Pseudoaneurysm, a Diagnostic Challenge - Case Series

Mycotic pseudoaneurysm (or infected pseudoaneurysm) is an infectious arteritis, leading to the destruction of the arterial wall with the formation of a blind, saccular outpouching contiguous with the arterial lumen. Delayed management or non-management of mycotic pseudoaneurysms is associated with high morbidity and mortality due to complications such as arterial rupture, hemorrhage, and fulminant sepsis. Earlier diagnosis of mycotic pseudoaneurysm is essential for time management. Multidetector computed tomography (MDCT) is a widely used imaging modality for detecting the mycotic pseudoaneurysm, its characterization, and vascular mapping. MDCT findings of mycotic pseudoaneurysm are blind, saccular outpouching of an artery with irregular arterial wall, perivascular soft-tissue mass, or edema. Uncommon results of MDCT include arterial lumen thrombosis, arterial wall calcification, and perivascular gas. Management of mycotic pseudoaneurysm includes endovascular stenting with graft repair, endovascular embolization, open surgery, medical therapy (intravenous antibiotics), or a combination of these. We report three cases of mycotic pseudoaneurysm affecting aortic isthmus, a segmental branch of the pulmonary artery, and the internal mammary artery. All cases posed a diagnostic challenge, which only on subsequent imaging revealed to be a mycotic pseudoaneurysm.

Mycotic Renal Artery Aneurysm Presenting as Critical Limb Ischemia in Culture-Negative Endocarditis

Mycotic renal artery aneurysms are rare and can be difficult to diagnose. Classic symptoms such as hematuria, hypertension, or abdominal pain can be vague or nonexistent. We report a case of a 53-year-old woman with a history of intravenous drug abuse presenting with critical limb ischemia, in which CT angiography identified a mycotic renal aneurysm. This aneurysm tripled in size from 0.46 cm to 1.65 cm in a 3-week interval. Echocardiography demonstrated aortic valve vegetations leading to a diagnosis of culture-negative endocarditis. The patient underwent primary resection and repair of the aneurysm, aortic valve replacement, and left below-knee amputation after bilateral common iliac and left superficial femoral artery stenting. At 1-year follow-up, her serum creatinine is stable and repaired artery remains patent.

Large intracranial aneurysm after transsphenoidal surgery for pituitary macroadenoma

Uncontrolled cerebrospinal fluid (CSF) leakage after transsphenoidal surgery (TSS) for pituitary adenoma can lead to meningitis. Intracranial mycotic pseudoaneurysm is a rare complication in central nervous system infection. Large single pseudoaneurysm is more uncommon. Most mycotic aneurysms occur due to endocarditis. The present patient had no heart problem and was infected by CSF leakage after transsphenoidal surgery. We present a case of large ruptured mycotic pseudoaneurysm as a complication of cerebral infection after TSS for pituitary macroadenoma.

Hepatic artery mycotic aneurysm associated with staphylococcal endocarditis with successful treatment: case report with review of the literature

Mycotic hepatic artery aneurysm is a vascular pathology associated with bacterial endocarditis. It is rare in occurrence after the introduction of effective antibiotics. We present a young patient with injection drug abuse associated staphylococcal endocarditis which was successfully treated with antibiotics and valve replacement who presented with abdominal pain. He was found to have mycotic aneurysm of hepatic artery which was successfully treated with coil embolization.

Involvement of the aorta in brucellosis: the forgotten, life-threatening complication. A systematic review

Human brucellosis is a disease of protean manifestations, and has been implicated in complications and focal disease in many human organ systems. However, little is collectively known about the background, the course, the clinical characteristics, the diagnostic issues raised, and the short- and long-term therapeutic approaches in patients with aortic involvement as a complication of brucellosis. With the aim to glean from the literature useful information to better understand and manage this complication, a computerized search without language restriction was conducted using PubMed and SCOPUS. An article was considered eligible for inclusion in the systematic review if it reported data on patients with involvement of the aorta due to a Brucella infection. The epidemiologic and clinical characteristics of 44 cases of brucellar aortic involvement found through the systematic review of the literature were analyzed together with those of two new cases that we treated in the recent past. This complication involved the ascending thoracic aorta in 18 cases (in 16 of them as a consequence of brucellar endocarditis), and the descending thoracic aorta or the abdominal aorta in the remaining 30 cases. In the latter it was associated with spondylodiscitis of the lumbar spine in 13 cases. History of or symptoms indicative of brucellosis were not universally present. Brucellar aortic involvement represents a possibly underdiagnosed and underreported complication with major morbidity and mortality potential. Experience with novel invasive therapeutic approaches remains limited. Early suspicion through detailed history and diagnosis, aided by advances in aortic imaging, would allow for better planning of therapeutic interventions.

Mycotic aneurysm of the tibioperoneal trunk: a first manifestation of an infected endocarditis

Infrapopliteal mycotic aneurysm resulting from endocarditis is rare, with only a few reported cases. We describe the case of a 28-year-old male patient who was suffering with pain and edema in the right leg. The ultrasound revealed an aneurysm of the right tibioperoneal trunk and a deep vein thrombosis (DVT). The patient was admitted and developed acute congestive heart failure, being diagnosed with possible endocarditis. A pseudo-aneurysm was revealed by arteriography. Aggressive antibiotic treatment was initiated, and open surgery confirmed a mycotic pseudo-aneurysm of the tibioperoneal trunk. To our knowledge, this is the 8th case reported of an infected aneurysm in this particular location.

From arteritis to mycotic aneurysm: visualization of the progression of mycotic aneurysm development following femoral arterial line insertion in an infant

Although uncommon, mycotic aneurysms in infants can be lethal because of the high risk of rapid expansion and rupture. Most catheter-associated mycotic aneurysms reported in the first year of life develop following umbilical artery catheterizations. We describe the sonographic detection of an early stage mycotic aneurysm in a 4-month-old following femoral artery catheterization complicated by methicillin-resistant Staphylococcus aureus (MRSA) septicemia. We also describe the sonographic and radiographic progression of this mycotic aneurysm before surgery.

Ruptured intracranial mycotic aneurysm in infective endocarditis: a natural history

Mycotic aneurysms are a rare cause of intracranial aneurysms that develop in the presence of infections such as infective endocarditis. They account for a small percentage of all intracranial aneurysms and carry a high-mortality rate when ruptured. The authors report a case of a 54-year-old man who presented with infective endocarditis of the mitral valve and acute stroke. He subsequently developed subarachnoid hemorrhage during antibiotic treatment, and a large intracranial aneurysm was discovered on CT Angiography. His lesion quickly progressed into an intraparenchymal hemorrhage, requiring emergent craniotomy and aneurysm clipping. Current recommendations on the management of intracranial Mycotic Aneurysms are based on few retrospective case studies. The natural history of the patient's ruptured aneurysm is presented, as well as a literature review on the management and available treatment modalities.

Listeria monocytogenes as a rare cause of mycotic aortic aneurysm

Mycotic aneurysms represent a diagnostic and therapeutic challenge still lacking general recommendations for optimal therapy. So far, Listeria monocytogenes (L. monocytogenes) is very rarely reported to be the causative organism of mycotic aortic aneurysms. We report 2 cases of mycotic abdominal aortic aneurysms due to L. monocytogenes infection being treated by radical debridement, open in situ reconstruction with aorto-bi-iliac Dacron grafts, and long-term antibiotic therapy. Both patients recovered well from surgery. Interestingly, the long-time follow-up for the first patient 9 years after surgery was entirely uneventful. Open debridement in an in situ reconstruction with Dacron grafts followed by antibiotic therapy seems to be a suitable therapeutic regime for mycotic aneurysms due to L. monocytogenes.

Cause of internal hemorrhage determined after exhumation: Report of one case

A 36-year-old woman consulted the medical emergency unit of a private health center for abdominal pain and gastroenteritis of 5 days duration. Acute right pyelonephritis was diagnosed. Five hours after admission she became unconscious in a state of clinical shock. She was transferred to an intensive care unit but resuscitation attempts were unsuccessful and she died 3h later. Three days after death, she was buried in the family vault. Five days after the burial, her husband lodged a complaint with the public prosecutor because he had not received a clear explanation from the physicians concerning the cause of his wife's death. After analysis of the medical records of the deceased by two forensic pathologists, a medicolegal autopsy was ordered by the public prosecutor. The corpse was exhumed and autopsy performed 9 days after death. Massive hemoperitoneum was diagnosed with a macroscopically ruptured subcapsular hematoma. Pathological study confirmed acute right pyelonephritis and demonstrated the precise cause of the hemorrhage: rupture of the hepatic artery at the hilar part, following infectious arteritis which was probably secondary to the acute pyelonephritis. To the best of our knowledge, this is the first published report of such a case.

Infected (mycotic) aneurysms: spectrum of imaging appearances and management

Infected aneurysms are uncommon. The aorta, peripheral arteries, cerebral arteries, and visceral arteries are involved in descending order of frequency. Staphylococcus and Streptococcus species are the most common causative pathogens. Early clinical diagnosis of infected aneurysms is challenging owing to their protean manifestations. Clinically apparent infected aneurysms are often at an advanced stage of development or are associated with complications, such as rupture. Nontreatment or delayed treatment of infected aneurysms often has a poor outcome, with high morbidity and mortality from fulminant sepsis or hemorrhage. Current state-of-the-art imaging modalities, such as multidetector computed tomography and magnetic resonance imaging, have replaced conventional angiography as minimally invasive techniques for detection of infected aneurysms in clinically suspected cases, as well as characterization of infected aneurysms and vascular mapping for treatment planning in confirmed cases. Doppler ultrasonography allows noninvasive assessment for infected aneurysms in the peripheral arteries. Imaging features of infected aneurysms include a lobulated vascular mass, an indistinct irregular arterial wall, perianeurysmal edema, and a perianeurysmal soft-tissue mass. Perianeurysmal gas, aneurysmal thrombosis, aneurysmal wall calcification, and disrupted arterial calcification at the site of the infected aneurysm are uncommon findings. Imaging-guided endovascular stent-graft repair and embolotherapy can be performed in select cases instead of open surgery. Familiarity with the imaging appearances of infected aneurysms should alert the radiologist to the diagnosis and permit timely treatment, which may include endovascular techniques.

Infected Aortic Aneurysms: Imaging Findings

PURPOSE

To determine the imaging characteristics of infected aortic aneurysms.

MATERIALS AND METHODS

Review of records of patients with surgical and/or microbiologic proof of infected aortic aneurysm obtained over a 25-year period revealed 31 aneurysms in 29 patients. This study included 21 men and eight women (mean age, 70 years). One radiologist reviewed 28 computed tomographic (CT) studies (22 patients underwent CT once and three patients underwent CT twice), 12 arteriograms (12 patients underwent arteriography once), eight nuclear medicine studies (six patients underwent nuclear medicine imaging once and one patient underwent nuclear medicine imaging twice), and three magnetic resonance (MR) studies (three patients underwent MR imaging once). Features evaluated included aneurysm size, shape, and location; branch involvement; aortic wall calcification; gas; radiotracer uptake on nuclear medicine studies; and periaortic and associated findings. The location of infected aortic aneurysms was compared with that of arteriosclerotic aneurysms.

RESULTS

Aneurysms were located in the ascending aorta (n = 2, 6%), descending thoracic aorta (n = 7, 23%), thoracoabdominal aorta (n = 6, 19%), paravisceral aorta (n = 2, 6%), juxtarenal aorta (n = 3, 10%), infrarenal aorta (n = 10, 32%), and renal artery (n = 1, 3%). Two patients had two infected aortic aneurysms. CT revealed 25 saccular (93%) and two fusiform (7%) aneurysms with a mean diameter at initial discovery of 5.4 cm (range, 1-11 cm). Paraaortic soft-tissue mass, stranding, and/or fluid was present in 13 (48%) of 27 aneurysms, and early periaortic edema with rapid aneurysm progression and development was present in three (100%) patients with sequential studies. Other findings included adjacent vertebral body destruction with psoas muscle abscess (n = 1, 4%), kidney infarct (n = 1, 4%), absence of calcification in the aortic wall (n = 2, 7%), and periaortic gas (n = 2, 7%). Angiography showed 13 saccular aneurysms with lobulated contour in 10 (77%). Nuclear medicine imaging showed increased activity consistent with infection in six (86%) of seven aneurysms. MR imaging showed three saccular aneurysms. Adjacent abnormal vertebral body marrow signal intensity was seen in one (33%) of three patients.

CONCLUSION

Saccular aneurysms (especially those with lobulated contour) with rapid expansion or development and adjacent mass, stranding, and/or fluid in an unusual location are highly suspicious for an infected aneurysm.

Hepatic artery aneurysm in a 10-year-old boy as a complication of infective endocarditis

Mycotic aneurysms occur from septic emboli in patients with infective endocarditis and may involve any artery, but frequently they are not detected before autopsy. The most common sites are the brain, abdominal aorta, sinus of Valsalva, ligated ductus arteriosus, and superior mesenteric, splenic, coronary, and pulmonary arteries. The authors report on a 10-year-old boy who had a mycotic aneurysm of the common hepatic artery, which developed during the course of infective endocarditis of the mitral valve and was cured successively using a platinum coil embolization technique.

Bacterial intracranial aneurysms

This is a retrospective study of 25 patients with bacterial intracranial aneurysms treated in a single department over a 20-year period. The clinical presentation, investigation and treatment of these patients is discussed. The outcome of the treatment is assessed and is thought to be not as poor as previously reported.

Rapid growth and early rupture of a primary mycotic aneurysm of the abdominal aorta

A case of a primary mycotic aneurysm of the abdominal aorta due to infection with Staphylococcus aureus is presented. The outcome was fatal because of rupture into the jejunum.

Extracranial mycotic aneurysms in infective endocarditis

Nine of 217 (4.15%) patients with infective endocarditis who were followed from October 1978 to February 1984 had extracranial mycotic aneurysms (MA). Age range of patients was 6-43 years (mean of 24.8 years) and 7 were male. Etiologic agents were Streptococcus viridans (3 cases), Staphylococcus aureus (2 cases), Staphylococcus epidermidis (1 case), and Pseudomonas aeruginosa (1 case). Two patients had negative blood cultures. The MA involved the arteries of the limbs (5 cases), thoracic (3 cases), and abdominal (1 case) arteries. The diagnosis was made by means of physical examination (5 cases), chest roentgenogram (2 cases), ultrasound examination (1 case), and aortography (1 case), at hospital admission (2 cases), early or before antibiotic therapy (2 cases), and from two days to six months after finishing antibiotic therapy (5 cases). All but one patient were operated upon due to MA; bleeding occurred in three cases; surgery was an emergency procedure in one case and performed from 8 to 58 days after the diagnosis of the MA in the others. Signs of infection at surgery were found in one case. In the others, further antibiotic therapy was not administered. There were no limb losses in the peripheral MA. Four patients received surgical treatment for endocarditis. There was one in-hospital death and another one 6 months later due to heart failure.

Neurologic complications of infective endocarditis

Neurologic complications continue to occur in approximately 30 per cent of all patients with infective endocarditis and represent a major factor associated with an increased mortality rate in that disease. Of these complications, cerebral embolism is the most common and the most important, occurring in as many as 30 per cent of all patients, most of whom ultimately die. Emboli that are infected also account for all the other complications (mycotic aneurysm, meningitis or meningoencephalitis, brain abscess) that may develop. Emboli are more common in patients with mitral valve infection and in those infected with more virulent organisms. Mycotic aneurysms (often preceded by an embolic event) occur more frequently and earlier in the course of acute endocarditis, rather than later, which is more common in the course of subacute disease. The management of a cerebral mycotic aneurysm depends on the presence or absence of hemorrhage, its anatomic location and the clinical course. Healing can occur during the course of effective antimicrobial therapy and thus will preclude the need for automatic surgery in all angiographically demonstrated aneurysms. The indication for surgical intervention must be evaluated on an individual basis. Meningitis is usually purulent when associated with virulent organisms, but the CSF may present an aseptic formula when associated with subarachnoid hemorrhage or multiple microscopic embolic lesions, infected or otherwise. Macroscopic brain abscesses are rare, but multiple microscopic abscesses are not uncommon in patients with acute endocarditis due to virulent organisms. Seizures are not uncommon in patients with infective endocarditis. Focal seizures are more commonly associated with acute emboli, whereas generalized seizures are more commonly associated with systemic metabolic factors. Penicillin neurotoxicity should be considered in seizure patients with compromised renal function who are receiving high doses of penicillin. The CSF tends to reflect the nature of the infecting organism rather than the nature of the neurologic complication, except when hemorrhage is present. Endocarditis due to virulent organisms, such as Staphylococcus aureus, is usually associated with a purulent CSF formula, whereas non-virulent organisms, such as "viridans" streptococci, usually have aseptic or normal CSF formulas.

Mycotic aneurysm due to Yersinia enterocolitica

Infections of the cardiovascular system, besides involving both natural and prosthetic heart valves, vascular grafts, and indwelling venous and arterial cannulas, may cause mycotic aneurysms. The latter frequently complicate endocarditis; however, they may occur as isolated phenomena. Enterobacteriaceae are uncommon etiologic agents in vascular infections; however, a patient is reported who presented initially with a bacteremia due to Yersinia enterocolitica biogroup 4 and despite antimicrobial therapy developed a mycotic aneurysm of the left internal carotid artery. Clinical manifestations, pathogenesis, and treatment of yersiniosis are reviewed.

Bacterial intracranial aneurysms

The treatment of 13 patients with bacterial intracranial aneurysms is reported. The incidence of bacterial intracranial aneurysms was 4% of all patients admitted with intracranial aneurysms and 3% of all patients admitted with bacterial endocarditis. Each patient had neurological signs or symptoms suggestive of intracranial disease prior to the diagnosis of an aneurysm. Alpha Streptococcus was the most common infecting organism. All patients were treated with specific, high-dose antibiotics, and five patients underwent surgery as well. There were no surgical deaths. Six of eight nonsurgically treated patients died. A review of the literature confirms a high mortality for patients treated with only antibiotics, and a low mortality for elective surgery. The authors conclude that 1) patients with bacterial endocarditis, who develop sudden severe headache, focal neurological signs or symptoms, or seizures, should undergo serial cerebral angiography every 7 to 10 days throughout their hospitalization; 2) if an aneurysm is identified it should be excised whenever possible; and 3) patients with proximal or multiple aneurysms should be considered for surgery.

Multiple intracranial aneurysms of inflammatory origin with subarachnoid hemorrhage

A 46-year-old Japanese woman with a long-standing history of bronchial asthma died of subarachnoid hemorrhage with intraventricular spread, during medication by a large dose of corticosteroids. On postmortem examination, eighteen isolated arterial aneurysms were found around the circle of Willis, one aneurysm of the right middle cerebral artery being ruptured. Most of the aneurysms were fusiform or cylindrical in shape, with circumferential dilatation of the arteries. A tendency for peripheral involvement was noted in the distribution of the aneurysms. Histological examination revealed various degrees and stages of inflammatory degradation of the walls of the aneurysms. An inflammatory origin of these aneurysms seemed highly likely.

Septic cerebral embolism

In order to study the effects of septic embolism on neurovascular structures, cerebral infarction was produced in a series of dogs by injecting silicone rubber cylinders through an internal carotid artery cannula. Each embolic particle was first incubated with one of four known bacterial pathogens. Death occurred in three animals on the second postoperative day, at which time ten other moribund dogs were sacrificed. Eleven animals made apparently uneventful recoveries from early hemiplegia and appeared well when sacrificed electively one to five weeks after embolism. Autopsies revealed subarachnoid and acute subdural hemorrhages in the early group with gross and microscopic evidence of mycotic aneurysm in each instance. Chronically surviving animals showed histological lesions in the putamen or temporal pole consistent with brain abscess. In this series, mycotic aneurysm with hemorrhage was an extremely dramatic complication of emboli infected with the virulent pathogens, Staphylococcus aureus and Escherichia coli , while brain abscess developed insidiously in ischemic areas, after embolism with the opportunistic pathogens, Streptococcus viridans and Enterococcus .