Clinical course of infectious intracranial aneurysm undergoing antibiotic treatment

LPS induces RGS-1 to promote infectious intracranial aneurysm formation and rupture by accelerating smooth muscle cell phenotypic switching

OBJECTIVE

Patients with infectious intracranial aneurysms (IIAs) have high mortality rates. Sepsis is an important condition that induces IIA. Smooth muscle cell (SMC) phenotypic switching may have a critical effect on sepsis-induced IIA, but its role remains unclear. Hence, we aimed to identify sepsis-induced target genes involved in SMC phenotypic switching and their underlying mechanisms.

METHODS AND RESULTS

RNA sequencing and bioinformatics analyses of samples from patients with intracranial aneurysms and sepsis identified RGS-1 as a common differentially expressed gene (DEG) involved in SMC phenotypic switching. Experimental verification demonstrated that lipopolysaccharide (LPS), a critical molecule in sepsis, increased RGS-1 levels, promoted SMC phenotypic switching and proliferation, and upregulated the expression of matrix metalloproteinases and inflammatory factors. Furthermore, qRT-PCR and immunofluorescence experiments confirmed that RGS-1 knockdown under LPS stimulation inhibited SMC phenotypic switching, cell proliferation, and decreases in matrix metalloproteinases and inflammatory factors. Mechanistically, western blotting, bioinformatics analyses, and chip assays revealed that RGS-1 activates the JNK-P38 pathway to promote SMC phenotypic switching and is regulated by the transcription factor STAT1.

CONCLUSION

LPS induces RGS-1 to promote IIA formation and rupture by accelerating SMC phenotypic switching.

Epidemiology and Risk Factors of Mycotic Aneurysm in Patients With Infective Endocarditis and the Impact of its Rupture in Outcomes. Analysis of a National Prospective Cohort

Background

Several aspects of the occurrence and management of mycotic aneurysm (MA) in patients with infective endocarditis (IE) have not been studied.

Objectives

To determine the incidence and factors associated with MA presence and rupture and to assess the evolution of those initially unruptured MA.

Methods

Prospective multicenter cohort including all patients with definite IE between January 2008 and December 2020.

Results

Of 4548 IE cases, 85 (1.9%) developed MA. Forty-six (54.1%) had intracranial MA and 39 (45.9%) extracranial MA. Rupture of MA occurred in 39 patients (45.9%). Patients with ruptured MA had higher 1-year mortality (hazard ratio, 2.33; 95% confidence interval, 1.49-3.67). Of the 55 patients with initially unruptured MA, 9 (16.4%) presented rupture after a median of 3 days (interquartile range, 1-7) after diagnosis, being more frequent in intracranial MA (32% vs 3.3%, P = .004). Of patients with initially unruptured MA, there was a trend toward better outcomes among those who received early specific intervention, including lower follow-up rupture (7.1% vs 25.0%, P = .170), higher rate of aneurysm resolution in control imaging (66.7% vs 31.3%, P = .087), lower MA-related mortality (7.1% vs 16.7%, P = .232), and lower MA-related sequalae (0% vs 27.8%, P = .045).

Conclusions

MA occurred in 2% of the patients with IE. Half of the Mas occurred in an intracranial location. Their rupture is frequent and associated with poor prognosis. A significant proportion of initially unruptured aneurysms result from rupture during the first several days, being more common in intracranial aneurysms. Early specific treatment could potentially lead to better outcomes.

Delayed formation and rupture of intracranial aneurysm following Abiotrophia defectiva endocarditis

Abiotrophia defectiva is a type of Streptococci and is a rare cause of infectious endocarditis. The progression and outcomes of infectious intracranial aneurysms (IIAs) associated with this species are unknown due to a limited number of reported cases. A woman in her 20s with a sudden headache had a subarachnoid haemorrhage on a head CT scan. Cerebral angiography showed an aneurysm on the right middle cerebral artery. She was diagnosed with infectious endocarditis caused by A. defectiva and underwent parent artery occlusion. Despite initiating targeted antibiotic therapy, a new IIA developed and ruptured 14 days postadmission. A second parent artery occlusion was performed on the new IIA. Following 6 weeks of continued antibiotic therapy, she underwent mitral valve repair and was discharged with no neurological symptoms. Endocarditis caused by A. defectiva can lead to the delayed formation of an IIA. Endovascular treatment was effective for repeated ruptured IIAs.

Identifying pyroptosis- and inflammation-related genes in intracranial aneurysms based on bioinformatics analysis

BACKGROUND

Intracranial aneurysm (IA) is the most common cerebrovascular disease, and subarachnoid hemorrhage caused by its rupture can seriously impede nerve function. Pyroptosis is an inflammatory mode of cell death whose underlying mechanisms involving the occurrence and rupture of IAs remain unclear. In this study, using bioinformatics analysis, we identified the potential pyroptosis-related genes (PRGs) and performed their inflammatory response mechanisms in IAs.

METHODS

The mRNA expression matrix of the IA tissue was obtained from the Gene Expression Omnibus database, and 51 PRGs were obtained from previous articles collected from PubMed. The differentially expressed PRGs (DEPRGs) were performed using R software. Subsequently, we performed enrichment analysis, constructed a protein-protein interaction network, performed weighted gene coexpression network analysis (WGCNA) and external validation using another dataset, and identified a correlation between hub genes and immune cell infiltration. Finally, the expression and tissue distribution of these hub genes in IA tissues were detected using Western blotting and immunohistochemical (IHC) staining.

RESULTS

In total, 12 DEPRGs associated with IA were identified in our analysis, which included 11 up-regulated and one down-regulated genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that the DEPRGs were mostly enriched in the NOD-like receptor signaling pathway, interleukin-1 beta production, and the inflammasome complex. Three hub genes, NLRP3, IL1B and IL18, were identified using Cytoscape software and the WGCNA correlation module, and external validation revealed statistically significant differences between the expression of these hub genes in the ruptured and unruptured aneurysm groups (p < 0.05). Furthermore, all AUC values were > 0.75. Immune cell infiltration analysis suggested that the hub genes are related to CD8 T cell, macrophages and mast cells. Finally, IHC staining revealed that the protein levels of these hub genes were higher in ruptured and unruptured IA tissues than in normal tissues (p < 0.05).

CONCLUSION

The results of bioinformatics analysis showed that pyroptosis is closely related to the formation and rupture of IA, and identified three potential hub genes involved in the pyroptosis and infiltration ofcells. Our findings may improve the understanding of the mechanisms underlying pyroptosis in IA.

Adding Fuel to the Fire: Infective Endocarditis and the Challenge of Cerebrovascular Complications

PURPOSE OF REVIEW

Infective endocarditis is a deadly disease and made more deadly by neurologic complications. We review the cerebrovascular complications of infective endocarditis and focus our discussion on medical and surgical management.

RECENT FINDINGS

While management of stroke in the setting of infective endocarditis differs from standard stroke treatment, mechanical thrombectomy has proven safe and successful. Optimal timing of cardiac surgery in the setting of stroke remains an area of debate, but additional observational studies continue to add more detail to the discussion. Cerebrovascular complications in the setting of infective endocarditis remain a high stakes clinical challenge. Timing of cardiac surgery in IE complicated by stroke exemplifies these dilemmas. While more studies have suggested that earlier cardiac surgery is likely safe for those with small ischemic infarcts, there remains a need for more data defining optimal timing of surgery in all forms of cerebrovascular involvement.

Flow Diversion as Destination Treatment of Intracranial Mycotic Aneurysms: A Retrospective Case Series

BACKGROUND

Mycotic aneurysms represent a rare type of intracranial aneurysm. Treatment options usually consist of coiling, clipping, or liquid embolization. Data regarding outcomes after flow diversion of mycotic aneurysms are sparse.

OBJECTIVE

To present a single-center case series regarding our experience with FD as definitive treatment for ruptured mycotic aneurysms initially treated with coil embolization.

METHODS

We retrospectively reviewed a prospectively maintained database of all cerebrovascular procedures performed at a single institution between 2017 and 2021 for cases that used FD for the management of intracranial mycotic aneurysms. Prospectively collected data included patient demographics, medical history, rupture status, aneurysm morphology, aneurysm location, and periprocedural complications. The main outcomes included neurological examination and radiographic occlusion rate on cerebral digital subtraction angiography.

RESULTS

Three patients with 4 ruptured mycotic aneurysms that were initially treated with coil embolization were identified that required retreatment. The aneurysms were located along the middle cerebral artery bifurcation (n = 2), posterior cerebral artery P1/2 junction (n = 1), and basilar artery apex (n = 1), which all demonstrated recurrence after initial coil embolization. Successful retreatment using flow diverting stents was performed in all 3 patients. At the last angiographic follow-up, all aneurysms demonstrated complete occlusion. No patients suffered new periprocedural complications or neurological deficits after FD.

CONCLUSION

Flow-diverting stents may be an effective treatment option for intracranial mycotic aneurysms that are refractory to previous endovascular coiling. Future studies are warranted to establish the associated long-term safety and clinical efficacy.

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.

Simultaneous intracerebral and subarachnoid hemorrhages caused by multiple infectious intracranial aneurysms treated endovascularly and by microsurgical clipping: illustrative case

BACKGROUND

Infected intracranial aneurysms are relatively rare but tend to occur in multiple locations. Establishing an optimal treatment strategy for multiple ruptured aneurysms is often challenging, especially when simultaneous ruptures occur in different locations. We report a case of simultaneous intracerebral and subarachnoid hemorrhages caused by the rupture of multiple infected intracranial aneurysms.

OBSERVATIONS

A 23-year-old male with a 2-week history of chronic fever presented with sudden onset of severe headache and visual disturbance. Computed tomography showed intracerebral hemorrhage in the right occipital lobe and subarachnoid hemorrhage in the area of the left Sylvian fissure. Further investigation documented Staphylococcus bacteremia, verrucae on the mitral valve, and aneurysms arising from the right posterior cerebral artery (PCA) and the left middle cerebral artery (MCA). A larger aneurysm arising from the PCA was successfully occluded endovascularly, but subsequent endovascular occlusion of the MCA aneurysm was unsuccessful because some important branches were observed extending from the aneurysm. The left MCA aneurysm was then obliterated by angioplastic clipping via left pterional craniotomy. The patient showed a favorable neurological recovery after treatment.

LESSONS

In such complex cases of infectious aneurysms, the method and timing of treatment need to be carefully determined based on the medical condition.

Risk factors of intracranial infection in patients after intracranial aneurysm surgery: Implication for treatment strategies

Postoperative intracranial infection after intracranial aneurysm is relatively common in clinical setting; it is necessary to analyze the clinical risk factors of postoperative intracranial infection, to provide reliable evidence to the management of aneurysm.Patients with intracranial aneurysm admitted from January 1, 2016, to November 30, 2020, are included. We collected the patient's personal and treatment data, and analyzed the risk factors of intracranial infection by multivariate logistic regression analysis. We compared the cerebrospinal fluid (CSF) indicators and serological indicators and analyzed their correlation with intracranial infection by spearman analysis.A total of 236 patients with intracranial aneurysm were included; the incidence of postoperative intracranial infection was 12.71%. There were significant differences in the diabetes, intraoperative aneurysm rupture, intraoperative CSF leakage, duration of surgery, and estimated blood loss between infection and non-infection group. Logistic regression indicated that diabetes [odds ratio (OR) 2.053, 95% confidence interval (95% CI) 1.092∼3.385], intraoperative aneurysm rupture (OR 2.239, 95% CI 1.173∼4.312), intraoperative CSF leakage (OR 2.168, 95% CI 1.033∼3.451), duration of surgery ≥360 minutes (OR 1.926, 95% CI 1.108∼2.655), and estimated blood loss ≥125 mL (OR 2.459, 95% CI 1.854∼3.447) were the independent risk factors of postoperative intracranial infection in patients with aneurysm surgery (all P < .05). Klebsiella pneumoniae, Escherichia coli, and Staphylococcus epidermidis were the top 3 commonly seen pathogens. Spearman analyses indicated that PCT, CRP, LA, LDH were all correlated with intracranial infection (all P < .05).There are multiple factors for the postoperative intracranial infection in patients with aneurysm. Coping strategies should be formulated targeted on those risks to improve the prognosis of patients.

Endovascular treatment of infectious intracranial aneurysms complicating infective endocarditis: a series of 31 patients with 55 aneurysms

PURPOSE

Endovascular treatment (EVT) has become a major option in management of infectious intracranial aneurysms (IIAs) complicating infective endocarditis. We report a retrospective, single-center series of consecutive patients with IIAs treated by EVT.

METHODS

Patients were included from January 2009 to July 2020. IIAs were diagnosed on DSA. Each patient underwent a neurological assessment before and after EVT and was followed up by imaging within 15 days of EVT. Safety was assessed on the evolution of NIHSS score. A minor stroke was defined as a worsening of NIHSS < 4 points. Efficacy was defined as the absence of hemorrhagic event during cardiac surgery and the exclusion of the IIA on control imaging.

RESULTS

Sixty-two IIAs (30 ruptured) were diagnosed in 31 patients. Fifty-six IIAs were diagnosed on the first DSA and 6 on the early control exploration. EVT was achieved in 55 IIAs by parent artery occlusion with glue in 52 distal IIAs and coils in 3 proximal IIAs. IIAs were located in 90.9% of cases on a fourth-division branch of a cerebral artery. The neurological examination remained unchanged in 29 patients (93.5%), and 2 patients suffered minor stroke. EVT was performed before cardiac surgery in 20/22 patients. All treated IIAs were excluded on follow-up imaging. No hemorrhage was observed during cardiac surgery or in the aftermath. Seven (11.3%) unruptured IIAs were not embolized.

CONCLUSION

EVT of IIAs by occlusion of the parent artery is effective in preventing rupture and carries no significant neurological risk.

Multiple mycotic aneurysms with infective endocarditis: A case report

Mycotic aneurysms are sometimes seen in patients with infective endocarditis. We report a case of infective endocarditis with multiple mycotic aneurysms. Although antibiotics were effective, mycotic aneurysms appeared in the cerebral, hepatic, and gastroepiploic arteries. A 55-year-old man presented with mitral valve endocarditis due to Streptococcus oralis. Surgical treatment was deferred because of cerebral hemorrhage. After antibiotic initiation, his fever and C-reactive protein levels declined, and blood culture was negative. However, he experienced repeated cerebral hemorrhage and the number of cerebral mycotic aneurysms increased. Additionally, his spleen ruptured and the number of mycotic aneurysms in the hepatic and gastroepiploic arteries increased. After embolization for mycotic aneurysm and mitral valve replacement, no mycotic aneurysms appeared. Regardless of whether laboratory data improve or not, multiple mycotic aneurysms sometimes appear, and cardiac surgery for infection control should be considered in the early phase.

Cerebrovascular Complication and Valve Surgery in Infective Endocarditis

Infective endocarditis (IE) with neurologic complications is common in patients with active IE. The most common and feared neurological complication of left-sided IE is cerebrovascular, from septic emboli causing ischemic stroke, intracranial hemorrhage (ICH), or an infectious intracranial aneurysm with or without rupture. In patients with cerebrovascular complications, valve replacement surgery is often delayed for concern of further neurological worsening. However, in circumstances when an indication for valve surgery to treat IE is present, the benefits of early surgical treatment may outweigh the potential neurologic deterioration. Furthermore, valve surgery has been associated with lower in-hospital mortality than medical therapy with intravenous antibiotics alone. Early valve surgery can be performed within 7 days of transient ischemic attack or asymptomatic stroke when medically indicated. Timing of valve surgery for IE after symptomatic medium or large symptomatic ischemic stroke or ICH remains challenging, and current data in the literature are conflicting about the risks and benefits. A delay of 2 to 4 weeks from the time of the cerebrovascular event is often recommended, balancing the risks and benefits of surgery. The range of timing of valve surgery varies depending on the clinical scenario, and is best determined by a multidisciplinary decision between cardiothoracic surgeons, cardiologists, infectious disease experts, and vascular neurologists in an experienced referral center.

Acute enlargement, morphological changes, and rupture of intracranial infectious aneurysm in infective endocarditis. Serial imaging

A 72-year-old man received a transcatheter aortic valve implantation (TAVI) 2 years ago for leakage of the degenerative bioprosthesis with Corevalve n°31 implantation, presented infective endocarditis (IE) (streptococcus sanguinis) of the bioprosthetic aortic valve. One month after antibiotic treatment was initiated, he presented a left-sided hemiplegia, a right frontal hematoma. MRI/contrast-enhanced magnetic resonance angiography (CE-MRA) revealed 2 infectious intracranial aneurysms (IIAs) of the right (10 mm) and left middle cerebral artery (MCA) (M2 segment, 5 mm). The right MCA IIA was treated within 1 day by glue-embolization. Seven days later, the patient acutely developed motor aphasia. CE-MRA showed significant enlargement (15 mm) and morphologic change of the ruptured left MCA IIA. This IIA was treated with Onyx-embolization. This case adds additional evidence that IIAs, during IE, can show rapid growth and morphological change over a 7 day course and emphasizes the imperative need of close imaging follow-up when IIAs are managed by antibiotic therapy.

Sepsis-associated encephalopathy and septic encephalitis: an update

INTRODUCTION

Sepsis-associated encephalopathy (SAE) and septic encephalitis (SE) are associated with increased mortality, long-term cognitive impairment, and focal neurological deficits.

AREAS COVERED

The PUBMED database was searched 2016-2020. The clinical manifestation of SAE is delirium, SE additionally is characterized by focal neurological symptoms. SAE is caused by inflammation with endothelial/microglial activation, increase of permeability of the blood-brain-barrier, hypoxia, imbalance of neurotransmitters, glial activation, axonal, and neuronal loss. Septic-embolic (SEE) and septic-metastatic encephalitis (SME) are characterized by focal ischemia (SEE) and small abscesses (SME). The continuum between SAE, SME, and SEE is documented by imaging techniques and autopsies. The backbone of treatment is rapid optimum antibiotic therapy. Experimental approaches focus on modulation of inflammation, stabilization of the blood-brain barrier, and restoration of membrane/mitochondrial function.

EXPERT OPINION

The most promising diagnostic approaches are new imaging techniques. The most important measure to fight delirium remains establishment of daily structure and adequate sensory stimuli. Dexmedetomidine and melatonin appear to reduce the frequency of delirium, their efficacy in SAE and SE remains to be established. Drugs already licensed for other indications or available as food supplements which may be effective in SAE are statins, L-DOPA/benserazide, β-hydroxybutyrate, palmitoylethanolamide, and tetracyclines or other bactericidal non-lytic antibiotics.

Neurological Outcomes of Patients With Mycotic Aneurysms in Infective Endocarditis

Background and Purpose

Mycotic aneurysms (MA) are rare neurovascular complications of infective endocarditis (IE). The natural history and outcomes of MA under contemporary medical therapy have not been well characterized. The purpose of this study is to describe treatments and outcomes of patients with ruptured and unruptured MA in IE, specifically in relation to medical versus surgical/endovascular treatment.

Methods

Retrospective chart review was performed at 3 US academic medical centers of adult patients with IE and MA. Information was collected regarding risk factors, imaging, treatments, and outcomes, including ischemic stroke, intracerebral hemorrhage, MA size changes, and inhospital mortality.

Results

Thirty-five patients with IE had 63 MA. Nineteen patients had at least one ruptured MA; 13 patients underwent invasive treatment and 6 received antibiotics alone. Of 19 patients on antibiotics alone (6 with at least one ruptured MA and 13 with unruptured MA), 14 underwent repeat imaging and 5 had enlarging MA. Of 16 patients treated invasively, 2 had unruptured MA initially treated with antibiotics but ultimately underwent intervention. No MA ruptured after aneurysm discovery. Fifteen patients underwent cardiothoracic surgery (CTS), of which 11 had unsecured MA and 4 had secured MA. No patients suffered perioperiative neurological events attributable to their MA. Three patients treated with antibiotics alone and 3 patients treated invasively died from causes unrelated to their MAs.

Conclusions

For patients with unruptured MA, treatment with antibiotics alone may have similar outcomes to invasive treatment. Further investigation is warranted to determine the risk of undergoing CTS with unsecured MA.