Bacterial Brain Abscess: An Outline for Diagnosis and Management

Neuroinfectious Emergencies

OBJECTIVE

This article describes nervous system infections and complications that lead to neurologic emergencies.

LATEST DEVELOPMENTS

New research on the use of dexamethasone in viral and fungal infections is reviewed. The use of advanced MRI techniques to evaluate nervous system infections is discussed.

ESSENTIAL POINTS

Neurologic infections become emergencies when they lead to a rapid decline in a patient's function. Emergent complications may result from neurologic infections that, if not identified promptly, can lead to permanent deficits or death. These complications include cerebral edema and herniation, spinal cord compression, hydrocephalus, vasculopathy resulting in ischemic stroke, venous thrombosis, intracerebral hemorrhage, status epilepticus, and neuromuscular respiratory weakness.

Endoscopic Access to Brain Abscess Due to Sinonasal Infection

BACKGROUND

Brain abscesses caused by sinonasal infections have become more common during the coronavirus pandemic, particularly due to the increase in sinonasal mucormycosis. This study aimed to evaluate the efficacy and safety of endoscopic endonasal brain abscess drainage as a therapeutic technique for these cases.

METHODS

Clinical outcomes and retrospective evaluations were performed in patients who underwent endoscopic endonasal brain abscess drainage between May 2019 and August 2022. A total of 7 patients diagnosed with 9 brain abscesses caused by sinonasal infections were included in the study. The main outcome of this study was to evaluate the success and safety of this technique.

RESULTS

The average age of the patients was 40.71 ± 14.17 years. The most common symptom observed in these patients was nasal discharge, and the frontal lobe was the most common site of abscess. Notably, the majority of cases were associated with COVID-19.

CONCLUSIONS

Based on the results of this study, endoscopic endonasal brain abscess drainage is considered a viable treatment option for skull base brain abscesses caused by sinonasal infections. Further research in this field can help establish this technique as a mainstay approach for managing brain abscesses at the skull base.

From Text to Insight: A Natural Language Processing-Based Analysis of Topics and Trends in Neurosurgery

BACKGROUND AND OBJECTIVES

Neurosurgical research is a rapidly evolving field, with new research topics emerging continually. To provide a clearer understanding of the evolving research landscape, our study aimed to identify and analyze the prevalent research topics and trends in Neurosurgery.

METHODS

We used BERTopic, an advanced natural language processing-based topic modeling approach, to analyze papers published in the journal Neurosurgery . Using this method, topics were identified based on unique sets of keywords that encapsulated the core themes of each article. Linear regression models were then trained on the topic probabilities to identify trends over time, allowing us to identify "hot" (growing in prominence) and "cold" (decreasing in prominence) topics. We also performed a focused analysis of the trends in the current decade.

RESULTS

Our analysis led to the categorization of 12 438 documents into 49 distinct topics. The topics covered a wide range of themes, with the most commonly identified topics being "Spinal Neurosurgery" and "Treatment of Cerebral Ischemia." The hottest topics of the current decade were "Peripheral Nerve Surgery," "Unruptured Aneurysms," and "Endovascular Treatments" while the cold topics were "Chiari Malformations," "Thromboembolism Prophylaxis," and "Infections."

CONCLUSION

Our study underscores the dynamic nature of neurosurgical research and the evolving focus of the field. The insights derived from the analysis can guide future research directions, inform policy decisions, and identify emerging areas of interest. The use of natural language processing in synthesizing and analyzing large volumes of academic literature demonstrates the potential of advanced analytical techniques in understanding the research landscape, paving the way for similar analyses across other medical disciplines.

Clinicopathologic characteristics of Nocardia brain abscesses: Necrotic and non-necrotic foci of various stages

Nocardia brain abscesses are rare bacterial infections associated with a high mortality rate, and their preoperative diagnosis can be difficult for various reasons including a nonspecific clinical presentation. While late-stage nocardial brain abscesses may be radiologically characteristic, early-stage lesions are nonspecific and indistinguishable from another inflammatory/infectious process and other mimics. Despite the paucity of previous histopathological descriptions, histopathological examination is critical for the identification of the pathogen, lesion stage(s), and possible coexisting pathology. In this study, we examined the clinical, radiological and histopathological features of 10 patients with brain nocardiosis. Microscopic findings were analysed in correlation with clinical and radiological features in 9 patients, which revealed that brain nocardiosis was characterized by numerous necrotic and non-necrotic foci of various stages (I-IV) along with Nocardia identification, as well as the leptomeningeal involvement in most cases, and co-infection of brain nocardiosis with toxoplasmosis in 2 patients. The imaging features were characteristic with a multilobulated/bilobed ring-enhancing appearance in 8 patients including 2 patients with multiple lobulated and non-lobulated lesions and 1 patient showing the progression from a non-lobulated to lobulated lesion. These findings suggest that nocardial brain abscesses particularly at late-stages share common characteristics. Nevertheless, given the complex pathologic features, including possible co-infection by other pathogens, nocardial brain abscesses remain a therapeutic challenge.

European society of Clinical Microbiology and Infectious Diseases guidelines on diagnosis and treatment of brain abscess in children and adults

SCOPE

These European Society of Clinical Microbiology and Infectious Diseases guidelines are intended for clinicians involved in diagnosis and treatment of brain abscess in children and adults.

METHODS

Key questions were developed, and a systematic review was carried out of all studies published since 1 January 1996, using the search terms 'brain abscess' OR 'cerebral abscess' as Mesh terms or text in electronic databases of PubMed, Embase, and the Cochrane registry. The search was updated on 29 September 2022. Exclusion criteria were a sample size <10 patients or publication in non-English language. Extracted data was summarized as narrative reviews and tables. Meta-analysis was carried out using a random effects model and heterogeneity was examined by I2 tests as well as funnel and Galbraith plots. Risk of bias was assessed using Risk Of Bias in Non-randomised Studies - of Interventions (ROBINS-I) (observational studies) and Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) (diagnostic studies). The Grading of Recommendations Assessment, Development and Evaluation approach was applied to classify strength of recommendations (strong or conditional) and quality of evidence (high, moderate, low, or very low).

QUESTIONS ADDRESSED BY THE GUIDELINES AND RECOMMENDATIONS

Magnetic resonance imaging is recommended for diagnosis of brain abscess (strong and high). Antimicrobials may be withheld until aspiration or excision of brain abscess in patients without severe disease if neurosurgery can be carried out within reasonable time, preferably within 24 hours (conditional and low). Molecular-based diagnostics are recommended, if available, in patients with negative cultures (conditional and moderate). Aspiration or excision of brain abscess is recommended whenever feasible, except for cases with toxoplasmosis (strong and low). Recommended empirical antimicrobial treatment for community-acquired brain abscess in immuno-competent individuals is a 3rd-generation cephalosporin and metronidazole (strong and moderate) with the addition of trimethoprim-sulfamethoxazole and voriconazole in patients with severe immuno-compromise (conditional and low). Recommended empirical treatment of post-neurosurgical brain abscess is a carbapenem combined with vancomycin or linezolid (conditional and low). The recommended duration of antimicrobial treatment is 6-8 weeks (conditional and low). No recommendation is offered for early transition to oral antimicrobials because of a lack of data, and oral consolidation treatment after ≥6 weeks of intravenous antimicrobials is not routinely recommended (conditional and very low). Adjunctive glucocorticoid treatment is recommended for treatment of severe symptoms because of perifocal oedema or impending herniation (strong and low). Primary prophylaxis with antiepileptics is not recommended (conditional and very low). Research needs are addressed.

Management of cerebral abscess with large ventricular septal defect in rural area: a case report

Cerebral abscess is an uncommon complication of cyanotic heart disease. However, it has a high case fatality rate, and its management requires a multidisciplinary approach. Earlier diagnosis would result in a better outcome. In this report, we presented a case of a 6-year-old boy with a cerebral abscess and a large ventricular septal defect, which was treated surgically in a rural area with a limited resources facility.

Clinical analysis, diagnosis, and treatment strategies for otogenic brain abscesses

Objective: To explore the clinical features, diagnosis, and treatment strategies for otogenic brain abscesses (OBA). Methods: Clinical data from 10 patients with OBA were analyzed retrospectively. Clinical characteristics, diagnosis, and treatment experiences were summarized. Results: Two were first diagnosed in the Department of Otorhinolaryngology, 5 in Neurosurgery, and 3 in other departments. There were 6 cases of temporal lobe abscess and 4 cases of cerebellar abscesses. Five cases were accompanied by 1 or more intracranial complications. Headache is a common presentation in all cases. The main pathogenic bacteria were anaerobic bacteria. All patients had no previous ear or brain surgery history, and no history of traumatic brain injury, 7 received surgical treatment in the neurosurgery and/or otolaryngology department. Two patients died, the other 8 fully recovered and so were discharged. Conclusions: Diagnosis and treatment of OBA must involve multiple departments. Multidisciplinary consultation (MDT) is crucial to the success of the first OBA diagnosis. The diagnosis and treatment team develops personalized treatment plans by integrating MDT treatment opinions and combining the actual condition of patients, thereby making the diagnosis and treatment of OBA accurate and timely.

Acute Porphyromonas gingivalis Subdural Abscess with Brain Abscess in the Left Temporal Lobe: A Case Report and Review of Literature

Background

Brain abscesses are a rare but serious complication of focal intracerebral infection.

Case Description

We present a patient of acute subdural abscess with brain abscess in the left temporal lobe. After craniotomy, combined with the Third Next Generation Sequencing and Gene Diagnosis (TNGS & GD) of abscess, we prescribed sensitive antibiotics; the patient recovers well and the abscess did not recur.

Conclusion

For patients with acute subdural abscess, combined craniotomy and the TNGS & GD of abscess could achieve good results.

Early switch to oral antimicrobials in brain abscess: a narrative review

BACKGROUND

Early switch to oral antimicrobials has been suggested as a treatment strategy in patients with brain abscess, but the practice is controversial.

OBJECTIVES

This review aimed to summarize the background, current evidence, and future perspectives for early transition to oral antimicrobials in patients with brain abscess.

SOURCES

The review was based upon a previous systematic review carried out during the development of the ESCMID guidelines on diagnosis and treatment of brain abscess. The search used 'brain abscess' or 'cerebral abscess' as text or MESH terms in PubMed, EMBASE, and the Cochrane Library. Studies included in the review were required to be published in the English language within the last 25 years and to have a study population of ≥10 patients. Other studies known by the authors were also included.

CONTENT

In this review, the background for some experts to suggest early transition to oral antimicrobials in patients with mild and uncomplicated brain abscess was clarified. Next, results from observational studies were summarized and limitations discussed. Indirect support for early oral treatment of brain abscess was described with reference to other serious central nervous system infections and general pharmacological considerations. Finally, variations within and between countries in the use of early transition to oral antimicrobials in patients with brain abscess were highlighted.

IMPLICATIONS

Early transition to oral antimicrobials in patients with uncomplicated brain abscess may be of benefit for patients due to convenience of treatment and potential decreased risks associated with prolonged hospitalization and intravenous lines. The strategy may also confer a more rational allocation of healthcare resources and decrease expenses. However, the benefit/risk ratio for this strategy remains unresolved at present.

Homeless Patient With Community-Acquired Methicillin-Resistant Staphylococcus aureus Brain Abscesses

Brain abscess secondary to community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection is a rare, yet highly fatal disease. This article presents the case of a 45-year-old homeless female with a medical history of bipolar disorder, seizure disorder, and substance use disorder who was admitted with altered mental status. Laboratory tests on admission revealed neutrophil-predominant leukocytosis, elevated inflammatory markers (erythrocyte sedimentation rate [ESR], C-reactive protein [CRP]), and lactic acid. MRI brain demonstrated multiple cerebral abscesses with surrounding edema and sagittal vein thrombosis. The patient was initiated on broad-spectrum antibiotics and underwent a right-sided minimally invasive needle biopsy of the abscess and left frontal craniotomy for abscess evacuation, the culture of which confirmed the diagnosis of MRSA infection. As the patient did not have any hospitalization or procedure in the recent past, a diagnosis of CA-MRSA was made. The patient's clinical status improved following the procedure and antibiotic administration, but she left against medical advice before completing treatment. This case highlights the importance of early recognition and aggressive management of CA-MRSA infections, especially in vulnerable populations such as the homeless.

Streptococcus constellatus Brain Abscess in a Middle-Aged Man With an Undiagnosed Patent Foramen Ovale

Brain abscess is a rare diagnosis. Common sources of infection include direct spread from otic sources, sinuses, or oral cavities, and hematogenous spread from distant sources, including the heart and lungs. Brain abscess with cultures growing oral flora species, in rare cases, may develop from bacteria in the oral cavity entering the bloodstream and then traveling to the brain via a patent foramen ovale. This report highlights a case of brain abscess caused by Streptococcus constellatus in a middle-aged man with an undiagnosed patent foramen ovale.

Brain Abscess and Risk of Cancer: A Nationwide Population-Based Cohort Study

Background and objectives:

Underlying occult cancer could potentially explain some of the observed increased long-term mortality among brain abscess patients.

Methods:

Nationwide, population-based healthcare registries were used to examine long-term risks of cancer in brain abscess patients from 1982 through 2016 compared with a population comparison cohort individually matched (10:1) on age, sex, and residence. Cumulative incidences and adjusted cause-specific hazard rate ratios (HRR) with 95% confidence intervals (CIs) for cancer were computed. Potential confounding by family-related factors was explored by comparing cumulative incidences of cancer among siblings of both groups.

Results:

Among 1,384 brain abscess patients (37% female, median age 50 years, IQR 33-63), cancer was observed in 218 (16%) compared with 1,657/13,838 (12%) in the comparison cohort yielding an adj. HRR of 2.09 (95% CI 1.79-2.45). Median time to diagnosis of cancer was 1.8 years (IQR 0.02-9.1) in brain abscess patients and 8.6 years (IQR 3.9-15.9) in comparison cohort. Among brain abscess patients, central nervous system and eye cancer was diagnosed in 59 (4.3%), of which 47/59 (80%) occurred within 90 days of the admission date, metastasizing cancer in 54 (3.9%), respiratory tract cancer in 48 (3.5%), and gastro-intestinal cancer in 36 (2.6%). Results remained consistent in almost all subgroups and in sensitivity analyses. Accounting for competing risk of death, the 1-, 5-, 10-, and 35-year cumulative incidence of cancer was 7% (95% CI 6-8), 11% (95% CI 9-12), 13% (95% CI 11-15), and 24% (95% CI 20-27) in brain abscess patients compared with 0.7% (95% CI 0.6-0.9), 4% (95% CI 4-5), 8% (95% CI 8-9), and 25% (95% CI 23-27) in the comparison cohort. The cumulative incidences of cancer among siblings of brain abscess patients was 10% and 12% among siblings of the comparison cohort.

Discussion:

Brain abscess was associated with substantially increased risk of cancer during the first ten years after diagnosis.

Overview and risk factors for postcraniotomy surgical site infection: A four-year experience

Objective:

Despite evidence favoring perioperative antibiotic prophylaxis (ABP) use in patients undergoing craniotomy to reduce rates of surgical site infections (SSIs), standardized protocols are lacking. We describe demographic characteristics, risk factors, and ABP choice in patients with craniotomy complicated with SSI.

Design:

Retrospective case series from January 1, 2017, through December 31, 2020.

Setting:

Tertiary-care referral center.

Patients:

Adults who underwent craniotomy and were diagnosed with an SSI.

Methods:

Logistic regression to estimate odds ratios and 95% confidence intervals to identify factors associated with SSIs.

Results:

In total, 5,328 patients undergoing craniotomy were identified during the study period; 59 (1.1%) suffered an SSI. Compared with non-SSI cases, patients with SSI had a significantly higher frequency of emergency procedures: 13.5% versus 5.8% (P = .02; odds ratio [OR], 2.52; 95% confidene interval [CI], 1.10–5.06; P = .031). Patients with SSI had a higher rate of a dirty (5.1% vs 0.9%) and lower rate of clean-contaminated (3.3% vs 14.5%) wound class than those without infection (P = .002). Nearly all patients received ABP before craniotomy (98.3% in the SSI group vs 99.6% in the non-SSI group; P = .10). Combination of vancomycin and cefazolin as dual therapy was more prevalent in the group of patients without infection (n = 1,761, 34.1%) than those with SSI (n = 4, 6.8%) (P < .001), associated with decreased odds for SSI (OR, 0.17; 95% CI, 0.005–0.42; P ≤ .001).

Conclusions:

SSI are frequently seen after an emergent neurosurgical procedure and a dirty wound classification. Combination of prophylactic cefazolin and vancomycin is associated with decreased risk for SSI.

[Successful microsurgical resection of a large brainstem abscess: case report and literature review]

OBJECTIVE

To present a patient with brainstem abscess treated by microsurgical resection.

CASE PRESENTATION

A 53-years-old female patient admitted to the neurosurgical department in a severe condition with symptoms of intracranial hypertension, hyperthermia, general infectious signs and laboratory manifestations of infectious process. Contrast-enhanced MRI revealed a large brainstem lesion (abscess). Retrosigmoid craniotomy with total microsurgical resection of the abscess was performed. External ventricular drainage was incerted on the second postoperative day due to progressive hydrocephalus with clinical deterioration, it was removed in 8 days. Slow positive dynamics was observed in postoperative period. The patient was discharged in 2 weeks after surgery.

CONCLUSION

There are no established algorithm for the treatment of brainstem abscesses. Therapeutic approach is advisable for small abscesses. There are 2 neurosurgical options for this lesion: stereotactic drainage and microsurgical resection with or without external ventricular drainage. Treatment strategy depends on location and size of abscess, as well as clinical state of the patient.

Clinical characteristics and outcome of primary brain abscess: a retrospective analysis

Background

Patients with primary brain abscess often present with atypical symptoms, and the outcome varies. We investigated the demographic, laboratory, and neuroimaging features of patients with brain abscess at our hospital and identified factors associated with their outcomes.

Methods

We retrospectively collected the data of patients diagnosed with primary brain abscess at our hospital between January 2011 and December 2020. Their clinical characteristics, predisposing factors, laboratory and neuroimaging findings, treatment, and outcome were analyzed.

Results

Of the 57 patients diagnosed with primary abscess, 51 (89.47%) were older than 40 years, and 42 (73.68%) were male. Only eight patients (14.04%) showed the classical triad of headache, fever, and focal neurological deficit. Fifteen patients (26.31%) had comorbidities, of which diabetes mellitus was the most common. Positive intracranial purulent material cultures were obtained in 46.15% of the patients, and gram-negative enteric bacteria were found in 33.33% of them, with Klebsiella pneumoniae being the most frequently observed. Surgical treatment, most commonly in the form of stereotactic drainage, was received by 54.39% of the patients. Good outcomes were achieved in 75.44% of the patients. Multivariate logistic regression analysis showed that patients with headaches were more likely to have a poor outcome (odds ratio 6.010, 95% confidence interval 1.114–32.407, p = 0.037).

Conclusions

Male patients and those older than 40 years were more susceptible to brain abscess than female patients and those younger than 40 years, respectively. Only a few patients showed the classical triad of clinical symptoms. Diabetes mellitus was the most common comorbidity. Positive intracranial specimens’ culture results were uncommon, with gram-negative enteric bacteria, especially Klebsiella pneumoniae, being the main organisms found. Most patients had a good outcome, and the presence of headache may influence the outcome.

Existing Data Sources for Clinical Epidemiology: The Danish Study Group of Infections of the Brain Database (DASGIB)

Central nervous system (CNS) infections are rare diseases that are associated with considerable morbidity and mortality. Increased knowledge based on contemporary data is a prerequisite for improved management and prevention of these serious conditions. Yet, population-based databases of patients hospitalized with CNS infections remain scarce. The Danish Study Group of Infections of the Brain (DASGIB) has prospectively registered information on all adults ≥18 years of age admitted with CNS infections at departments of infectious diseases in Denmark since 2015. The main variables collected are baseline demographics, blood and cerebrospinal fluid tests, imaging results, and outcome using the Glasgow Outcome Scale score. To investigate important aspects for each type of CNS infections, additional variables are included specifically for bacterial meningitis, viral meningitis, encephalitis, brain abscess, neurosyphilis, and Lyme neuroborreliosis. From 2015 to 2020, a total of 3579 cases of CNS infections have been recorded in the DASGIB database. Using the unique civil registration number assigned to all Danish residents, the database can be unambiguously linked with nationwide healthcare registries at the individual level. This enables researchers to conduct detailed population-based and longitudinal observational studies of risk and prognosis of CNS infections and to compare them with matched population cohorts. The database is well-suited for epidemiological research and the DASGIB network forms a solid infrastructure for future national and international collaborations.

Multiple brain abscesses due to Listeria monocytogenes infection in a patient with systemic lupus erythematosus: A case report and literature review

AIM

To review the clinical features of systemic lupus erythematosus (SLE) complicated by central nervous system (CNS) infection due to Listeria monocytogenes.

METHOD

A patient with SLE receiving high-dose glucocorticoids combined with cyclophosphamide who developed multiple brain abscesses due to Listeria infection is described. The case is compared with known cases in a literature review.

RESULTS

A review of the literature showed that CNS infections are rare bacterial complications of SLE, but they can be a significant cause of mortality, especially those due to L. monocytogenes. The most significant risk factor for listerial meningitis is a prior history of receiving immunosuppressive therapy. At-risk patients should avoid unpasteurized milk and soft cheeses along with deli-style, ready-to-eat prepared meats, particularly poultry products. The case we report is the fifth SLE patient with multiple brain abscesses due to L. monocytogenes, and the first to be discharged with no sequelae. Timely and accurate identification and treatment of CNS infections and neuropsychiatric lupus are very important for favorable disease prognosis.

CONCLUSION

Repeated blood culture is helpful for early diagnosis, and empirical anti-infective treatment that covers L. monocytogenes is recommended for SLE patients with risk factors when CNS infection occurs. A comprehensive assessment might be helpful to distinguish CNS infections from neuropsychiatric SLE. For severe infection, the dosage of steroids does not need to be reduced immediately but can be gradually adjusted based on the results of a comprehensive evaluation of the disease.