Brain abscess

Cognitive and everyday functioning after bacterial brain abscess: a prospective study of functional recovery from 8 weeks to 1 year post-treatment

OBJECTIVE

A bacterial brain abscess may damage surrounding brain tissue by mass effect, inflammatory processes, and bacterial toxins. The aim of this study was to examine cognitive and functional outcomes at 8 weeks and 1 year following acute treatment.

METHODS

Prospective study of 20 patients with bacterial brain abscess (aged 17-73 years; 45% females) with neuropsychological assessment at 8 weeks and 1 year post-treatment. Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A) and Patient Competence Rating Scale (PCRS) were used to assess everyday functioning and administered to patients and informants.

RESULTS

Cognitive impairment was found in 30% of patients at 8 weeks and 22% at 1 year. Significant improvements were seen on tests of perceptual reasoning, attention, verbal fluency, and motor abilities (p < 0.05). At 1 year, 45% had returned to full-time employment. Nevertheless, patients and their informants obtained scores within the normal range on measures of everyday functioning (PCRS and BRIEF-A) at 8 weeks and 1 year. No significant improvements on these measures emerged over time.

CONCLUSION

Residual long-term cognitive impairment and diminished work ability affected 22% and 45% of patients one year after BA. Persistent cognitive impairment emphasizes the importance of prompt acute treatment and cognitive rehabilitation.

Robotic-assisted stereotactic drainage of cerebral abscess and placement of ventriculostomy

BACKGROUND

Robotic surgery has found increasing use in multiple subfields of neurosurgery. While the initial applications of stereotactic robotic surgery were for the placement of electrodes for extra-operative seizure monitoring, this technique has become increasingly relevant in other areas of neurosurgery. To the best of our knowledge, we report the first case of successful robotic surgery utilization to drain a cerebral abscess and place an external ventricular drain.

CASE REPORT

The authors demonstrate a novel use for stereotactic robotic assistance to drain a cerebral abscess and place ventriculostomy in a 74-year-old female patient who presented with a left basal ganglia Streptococcus intermedius abscess and concomitant ventriculitis. Drainage of a deep-seated abscess and placement of ventriculostomy was successfully performed in this patient without intraoperative difficulties or complications. The total operative time, including registration was 64 minutes and the estimated blood loss was 25 mL. The patient recovered well and was discharged to inpatient rehabilitation on postoperative day 19.

CONCLUSIONS

The use of robotic surgery to drain cerebral abscesses and place ventriculostomies is technically feasible and may potentially decrease operative time and increase accuracy and safety.

Update and approach to patients with brain abscess

PURPOSE OF REVIEW

The epidemiology of brain abscess has changed in recent decades. Moreover, acute and long-term management remains challenging with high risks of mortality and neurological sequelae. This review describes recent advances in epidemiology, diagnosis, and treatment of brain abscess.

RECENT FINDINGS

The incidence of brain abscess is increasing, especially among elderly individuals. Important predisposing conditions include dental and ear-nose-throat infections, immuno-compromise, and previous neurosurgery. Molecular-based diagnostics have improved our understanding of the involved microorganisms and oral cavity bacteria including anaerobes are the predominant pathogens. The diagnosis relies upon a combination of magnetic resonance imaging, neurosurgical aspiration or excision, and careful microbiological examinations. Local source control by aspiration or excision of brain abscess combined with long-term antimicrobials are cornerstones of treatment. Long-term management remains important and should address neurological deficits including epilepsy, timely diagnosis and management of comorbidities, and potential affective disorders.

SUMMARY

A multidisciplinary approach to acute and long-term management of brain abscess remains crucial and source control of brain abscess by neurosurgery should be pursued whenever possible. Numerous aspects regarding diagnosis and treatment need clarification. Nonetheless, our understanding of this complicated infection is rapidly evolving.

Ultrasound guided brain abscess aspiration

A brain abscess is a neurosurgical emergency and frequently requires drainage to relieve intracranial pressure and identify the offending organism. Surgical adjuncts including neuronavigation and intra-operative CT and MRI facilitate surgery, but have limitations, including cost and not offering real time intracranial views. Intra-operative ultrasound is a fast and relatively cheap tool which offers live, real time imaging and visualisation of an abscess being aspirated, but is less frequently used. We describe our technique of ultrasound guidance as an adjunct with neuronavigation for brain abscess aspiration, review the literature on surgical adjuncts and remind the neurosurgical community of its value in this and other cranial procedures. We summarise our recent experience in its use in six patients with a brain abscess. There is a learning curve to using intra-operative ultrasound, but we recommend its routine use in abscess drainage surgery.

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.

Central nervous system infections in the tropics

PURPOSE OF REVIEW

Emerging and re-emerging central nervous system (CNS) infections are a major public health concern in the tropics. The reasons for this are myriad; climate change, rainfall, deforestation, increased vector density combined with poverty, poor sanitation and hygiene. This review focuses on pathogens, which have emerged and re-emerged, with the potential for significant morbidity and mortality.

RECENT FINDINGS

In recent years, multiple acute encephalitis outbreaks have been caused by Nipah virus, which carries a high case fatality. Arboviral infections, predominantly dengue, chikungunya and Zika are re-emerging increasingly especially in urban areas due to changing human habitats, vector behaviour and viral evolution. Scrub typhus, another vector borne disease caused by the bacterium Orientia tsutsugamushi , is being established as a leading cause of CNS infections in the tropics.

SUMMARY

A syndromic and epidemiological approach to CNS infections in the tropics is essential to plan appropriate diagnostic tests and management. Rapid diagnostic tests facilitate early diagnosis and thus help prompt initiation and focusing of therapy to prevent adverse outcomes. Vector control, cautious urbanization and deforestation, and reducing disturbance of ecosystems can help prevent spread of vector-borne diseases. Regional diagnostic and treatment approaches and specific vaccines are required to avert morbidity and mortality.

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.

Multi-organ involvement caused by Scedosporium apiospermum infection after near drowning: a case report and literature review

BACKGROUND

Scedosporium apiospermum (S. apiospermum) is a rare fungal pathogen that causes disseminated infections. It rarely affects immunocompetent individuals and has a poor prognosis.

CASE PRESENTATION

A 37-year-old woman presented with multiple lesions in the lungs, brain, and eyes, shortly after near drowning in a car accident. The primary symptoms were chest tightness, limb weakness, headache, and poor vision in the left eye. S. apiospermum infection was confirmed by metagenomic next-generation sequencing (mNGS) of intracranial abscess drainage fluid, although intracranial metastases were initially considered. After systemic treatment with voriconazole, her symptoms improved significantly; however, she lost vision in her left eye due to delayed diagnosis.

CONCLUSION

While S. apiospermum infection is rare, it should be considered even in immunocompetent patients. Prompt diagnosis and treatment are essential. Voriconazole may be an effective treatment option.

A case report of treatment of a streptococcal brain abscess with ceftobiprole supported by the measurement of drug levels in the cerebrospinal fluid

In this paper, we describe the case of a patient admitted to our hospital because of a brain abscess due to Streptococcus intermedius. The management of brain abscess is challenging given the limited potential drug options with effective penetration into both the central nervous system and the abscess capsule to achieve adequate therapeutic concentrations. Due to the high anti-streptococcal activity of ceftobiprole and the availability of ceftobiprole therapeutic drug monitoring in our hospital, we decided to treat the patient with ceftobiprole. To maximize the antimicrobial effect of ceftobiprole, we chose a prolonged intravenous infusion, and we monitored its concentrations in both plasma and cerebrospinal fluid.

Brain Abscess Caused by Oral Cavity Bacteria: A Nationwide, Population-based Cohort Study

BACKGROUND

Oral cavity bacteria are the most frequent etiology of brain abscess. Yet, data on the clinical presentation and outcome are scarce.

METHODS

We performed a nationwide, population-based study comprising all adults (aged ≥18 years) with brain abscess due to oral cavity bacteria in Denmark from 2007 through 2020. Prognostic factors for unfavorable outcome (Glasgow outcome scale, 1-4) were examined using modified Poisson regression to compute adjusted relative risks (RRs) with 95% confidence intervals (CIs).

RESULTS

Among 287 identified patients, the median age was 58 years (interquartile range, 47-66), and 96 of 287 (33%) were female. Preexisting functional impairment was absent or mild in 253 of 280 (90%), and risk factors for brain abscess included immunocompromise in 95 of 287 (33%), dental infection in 68 of 287 (24%), and ear-nose-throat infection in 33 of 287 (12%). Overall, a neurological deficit was present in 246 of 276 (86%) and in combination with headache and fever in 64 of 287 (22%). Identified microorganisms were primarily the Streptococcus anginosus group, Fusobacterium, Actinomyces, and Aggregatibacter spp., and 117 of 287 (41%) were polymicrobial. Unfavorable outcome occurred in 92 of 246 (37%) at 6 months after discharge and was associated with antibiotics before neurosurgery (RR, 3.28; 95% CI, 1.53-7.04), rupture (RR, 1.89; 95% CI, 1.34-2.65), and immunocompromise (RR, 1.80; 95% CI, 1.29-2.51), but not with specific targeted antibiotic regimens. Identified dental infection was associated with favorable prognosis (RR, 0.58; 95% CI, .36-.93).

CONCLUSIONS

Brain abscess due to oral cavity bacteria often occurred in previously healthy individuals without predisposing dental infections. Important risk factors for unfavorable outcome were rupture and immunocompromise. However, outcome was not associated with specific antibiotic regimens supporting carbapenem-sparing strategies.

Brain abscess - A rare confounding factor for diagnosis of post-traumatic epilepsy after lateral fluid-percussion injury

OBJECTIVE

To assess the prevalence of brain abscesses as a confounding factor for the diagnosis of post-traumatic epilepsy (PTE) in a rat model of lateral fluid-percussion-induced (FPI) traumatic brain injury (TBI).

METHODS

This retrospective study included 583 rats from 3 study cohorts collected over 2009-2022 in a single laboratory. The rats had undergone sham-operation or TBI using lateral FPI. Rats were implanted with epidural and/or intracerebral electrodes for electroencephalogram recordings. Brains were processed for histology to screen for abscess(es). In abscess cases, (a) unfolded cortical maps were constructed to assess the cortical location and area of the abscess, (b) the abscess tissue was Gram stained to determine the presence of gram-positive and gram-negative bacteria, and (c) immunostaining was performed to detect infiltrating neutrophils, T-lymphocytes, and glial cells as tissue biomarkers of inflammation. In vivo and/or ex vivo magnetic resonance images available from a subcohort of animals were reviewed to evaluate the presence of abscesses. Plasma samples available from a subcohort of rats were used for enzyme-linked immunosorbent assays to determine the levels of lipopolysaccharide (LPS) as a circulating biomarker for gram-negative bacteria.

RESULTS

Brain abscesses were detected in 2.6% (15/583) of the rats (6 sham, 9 TBI). In histology, brain abscesses were characterized as vascularized encapsulated lesions filled with neutrophils and surrounded by microglia/macrophages and astrocytes. The abscesses were mainly located under the screw electrodes, support screws, or craniectomy. Epilepsy was diagnosed in 60% (9/15) of rats with an abscess (4 sham, 5 TBI). Of these, 67% (6/9) had seizure clusters. The average seizure frequency in abscess cases was 0.436 ± 0.281 seizures/d. Plasma LPS levels were comparable between rats with and without abscesses (p > 0.05).

SIGNIFICANCE

Although rare, a brain abscess is a potential confounding factor for epilepsy diagnosis in animal models of structural epilepsies following brain surgery and electrode implantation, particularly if seizures occur in sham-operated experimental controls and/or in clusters.

Brain abscess from oral microbiota approached by metagenomic next-generation sequencing: A case report and review of literature

BACKGROUND

Brain abscess is a serious and potentially fatal disease caused primarily by microbial infection. Although progress has been made in the diagnosis and treatment of brain abscesses, the diagnostic timeliness of pathogens needs to be improved.

CASE SUMMARY

We report the case of a 54-year-old male with a brain abscess caused by oral bacteria. The patient recovered well after receiving a combination of metagenomic next-generation sequencing (mNGS)-assisted guided medication and surgery.

CONCLUSION

Therefore, mNGS may be widely applied to identify the pathogenic microorganisms of brain abscesses and guide precision medicine.

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.

Clinical characteristics and outcomes of children with non-sinogenic Brain infections

BACKGROUND

Central Nervous System (CNS) suppurative infections are serious but rare conditions in the paediatric population. Data on long-term neurocognitive and quality of life outcomes in children recovering from these infections are lacking.

METHODS

A retrospective cohort review of children <16 years with non-sinogenic infections undergoing neurosurgery was conducted. Data for patients admitted to Children's Health Ireland at Temple St between 2008-2021 were analysed for clinical and microbiological profiles. Follow-up reviews evaluating neurological and academic sequelae and quality of life were performed. Categorical variables were analysed for unfavourable outcome with a p < 0.05 significance value.

RESULTS

Forty patients were included with a mean age of 4.5 years and equal gender distribution. Fever (68%) and vomiting (58%) were the most common presenting complaints. Only fourteen (35%) patients presented with the classic triad of fever, headache, and focal neurological deficit. Meningitis/Encephalitis was the most common cause of suppurative infection (40%). Predisposing factors included congenital heart disease (18%), prematurity (15%) and immunocompromised status (10%). More patients received an initial Burr hole aspiration (73%) than Craniotomy (27%). The re-operation rate was higher in the craniotomy group (45%) compared to the burr hole group (34%), but this was not statistically significant (p = 0.522). Four patients died (10%) including two intra-hospital deaths (5%). Male gender (p = 0.047) and multiple abscesses (p = 0.041) were associated with unfavourable outcome at discharge. Mobility impairment was the most affected determinant of quality of life.

CONCLUSION

CNS suppurative infections are associated with long-term neurocognitive sequelae in children. Multiple abscesses and male gender are associated with unfavourable GOS on discharge. Children are still left with mobility impairment (25%), personality changes (23%) and intellectual disability (18%) at an average of 5 years. Long-term follow up with multidisciplinary input is required. Further research should focus on evaluating long-term HRQoL in children.

Bacterial Brain Abscesses Expand Despite Effective Antibiotic Treatment: A Process Powered by Osmosis Due to Neutrophil Cell Death

BACKGROUND AND OBJECTIVES

A bacterial brain abscess is an emergency and should be drained of pus within 24 hours of diagnosis, as recently recommended. In this cross-sectional study, we investigated whether delaying pus drainage entails brain abscess expansion and what the underlying mechanism might be.

METHODS

Repeated brain MRI of 47 patients who did not undergo immediate pus drainage, pus osmolarity measurements, immunocytochemistry, proteomics, and 18F-fluorodeoxyglucose positron emission tomography.

RESULTS

Time from first to last MRI before neurosurgery was 1 to 14 days. Abscesses expanded in all but 2 patients: The median average increase was 23% per day (range 0%-176%). Abscesses expanded during antibiotic therapy and even if the pus did not contain viable bacteria. In a separate patient cohort, we found that brain abscess pus tended to be hyperosmolar (median value 360 mOsm; range 266-497; n = 14; normal cerebrospinal fluid osmolarity is ∼290 mOsm). Hyperosmolarity would draw water into the abscess cavity, causing abscess expansion in a ballooning manner through increased pressure in the abscess cavity. A mechanism likely underlying pus hyperosmolarity was the recruitment of neutrophils to the abscess cavity with ensuing neutrophil cell death and decomposition of neutrophil proteins and other macromolecules to osmolytes: Pus analysis showed the presence of neutrophil proteins (protein-arginine deiminases, citrullinated histone, myeloperoxidase, elastase, cathelicidin). Previous studies have shown very high levels of osmolytes (ammonia, amino acids) in brain abscess pus. 18F-fluorodeoxyglucose positron emission tomography showed focal neocortical hypometabolism 1 to 8 years after brain abscess, indicating long-lasting damage to brain tissue.

CONCLUSION

Brain abscesses expand despite effective antibiotic treatment. Furthermore, brain abscesses cause lasting damage to surrounding brain tissue. These findings support drainage of brain abscesses within 24 hours of diagnosis.

Brain abscess of odontogenic origin: A case report and literature review

BACKGROUND

The objective of this study is to investigate and understand the characteristics of odontogenic brain abscess.

METHODS

A case of brain abscess suspected to be caused by odontogenic infection was documented, and a comprehensive analysis and summary of odontogenic brain abscess cases reported in various countries over the past 20 years was conducted.

RESULTS

Based on the analysis and synthesis of both the present and previous reports, we have examined and consolidated the distinctive features of odontogenic brain abscess, the potential transmission pathway of pathogenic bacteria, diagnostic assertions, verification techniques, and crucial considerations during treatment.

CONCLUSION

This investigation contributes to an enhanced comprehension and improved clinical identification of odontogenic brain abscess.

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.

Brain abscess following kidney transplantation: A single centre observational study from North India

Background

Amongst the infections in kidney transplant recipients, brain abscess represents an uncommon life-threatening complication. Mortality continues to be high despite improvements in diagnostics and therapeutics.

Method

We conducted an observational study, describing the incidence, presentation, implicating pathogen, management and outcome of brain abscess following kidney transplantation at our centre.

Result

Amongst the 1492 patients who underwent kidney transplantation at our centre between June 1991 and January 2023 (cumulative follow-up: 4936 patient-years), five females and four males, developed brain abscesses. The incidence proportion (risk) is 0.6% with an incidence rate of 6.03 cases per 1000 patient years. The median duration from transplant to development of brain abscess was 5 weeks (range: 4 weeks to 9 years). The commonest presentation was a headache. A definitive microbiological diagnosis was established in eight out of nine patients. The commonest implicated organism was a dematiaceous fungus, Cladophialophora bantiana (3 patients, 33.3%). Despite the reduction in immunosuppression, surgical evacuation and optimal medical therapy, five (55.55%) patients succumbed to their illness.

Conclusions

Brain abscesses following kidney transplantation is an uncommon, life-threatening condition. It usually occurs in the early post-transplant period and the presentation is often subtle. Unlike immunocompetent individuals, a fungus is the most common causative organism in those with solid organ transplants. The management includes a reduction in immunosuppression, early antimicrobial therapy, and surgical decompression.

Can Perfusion-Based Brain Tissue Oxygenation MRI Support the Understanding of Cerebral Abscesses In Vivo?

PURPOSE

The clinical condition of a brain abscess is a potentially life-threatening disease. The combination of MRI-based imaging, surgical therapy and microbiological analysis is critical for the treatment and convalescence of the individual patient. The aim of this study was to evaluate brain tissue oxygenation measured with dynamic susceptibility contrast perfusion weighted imaging (DSC-PWI) in patients with brain abscess and its potential benefit for a better understanding of the environment in and around brain abscesses.

METHODS

Using a local database, 34 patients (with 45 abscesses) with brain abscesses treated between January 2013 and March 2021 were retrospectively included in this study. DSC-PWI imaging and microbiological work-up were key inclusion criteria. These data were analysed regarding a correlation between DSC-PWI and microbiological result by quantifying brain tissue oxygenation in the abscess itself, the abscess capsula and the surrounding oedema and by using six different parameters (CBF, CBV, CMRO2, COV, CTH and OEF).

RESULTS

Relative cerebral blood flow (0.335 [0.18-0.613] vs. 0.81 [0.49-1.08], p = 0.015), relative cerebral blood volume (0.44 [0.203-0.72] vs. 0.87 [0.67-1.2], p = 0.018) and regional cerebral metabolic rate for oxygen (0.37 [0.208-0.695] vs. 0.82 [0.55-1.19], p = 0.022) were significantly lower in the oedema around abscesses without microbiological evidence of a specific bacteria in comparison with microbiological positive lesions.

CONCLUSIONS

The results of this study indicate a relationship between brain tissue oxygenation status in DSC-PWI and microbiological/inflammatory status. These results may help to better understand the in vivo environment of brain abscesses and support future therapeutic decisions.

Bacterial Brain Abscesses in a Patient With Transposition of the Great Arteries and Interventricular Communication

Brain abscesses are localized infections in the brain's parenchyma, characterized by inflammation, pus formation, and the development of a surrounding capsule. These lesions typically occur due to underlying factors such as immunosuppression, ear and sinus infections, and contamination during neurosurgery. While brain abscesses are a life-threatening complication of cyanotic heart defects, they are rarely reported, with only sporadic cases previously documented. This article presents the case of an eight-year-old male patient with an uncorrected transposition of the great arteries, who was evaluated for symptoms including headache, fever, and neurological focalization. Diagnostic imaging revealed three lesions consistent with brain abscesses. Furthermore, the causal agents were identified as Streptococcus intermedius and Fusobacterium spp., representing oral microorganisms. Additionally, the patient exhibited poor oral hygiene and dental caries in multiple teeth. This article discusses and integrates the possible pathophysiological mechanisms that allowed a localized dental infection to spread hematogenously and cause brain abscesses in this patient. Prompt management of the infectious source is crucial to prevent a poor prognosis associated with brain abscesses. Therefore, this case emphasizes the importance of regular dental assessments and thromboprophylaxis for patients with underlying cardiomyopathies that cause right-to-left shunting to prevent potential complications.

A Canadian National Survey of the Neurosurgical Management of Intracranial Abscesses

OBJECTIVE

Intracerebral abscess is a life-threatening condition for which there are no current, widely accepted neurosurgical management guidelines. The purpose of this study was to investigate Canadian practice patterns for the medical and surgical management of primary, recurrent, and multiple intracerebral abscesses.

METHODS

A self-administered, cross-sectional, electronic survey was distributed to active staff and resident members of the Canadian Neurosurgical Society and Canadian Neurosurgery Research Collaborative. Responses between subgroups were analyzed using the Chi-square test.

RESULTS

In total, 101 respondents (57.7%) completed the survey. The majority (60.0%) were staff neurosurgeons working in an academic, adult care setting (80%). We identified a consensus that abscesses >2.5 cm in diameter should be considered for surgical intervention. The majority of respondents were in favor of excising an intracerebral abscess over performing aspiration if located superficially in non-eloquent cortex (60.4%), located in the posterior fossa (65.4%), or causing mass effect leading to herniation (75.3%). The majority of respondents were in favor of reoperation for recurrent abscesses if measuring greater than 2.5 cm, associated with progressive neurological deterioration, the index operation was an aspiration and did not include resection of the abscess capsule, and if the recurrence occurred despite prior surgery combined with maximal antibiotic therapy. There was no consensus on the use of topical intraoperative antibiotics.

CONCLUSION

This survey demonstrated heterogeneity in the medical and surgical management of primary, recurrent, and multiple brain abscesses among Canadian neurosurgery attending staff and residents.

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.

Clinical Features and Diagnosis of Intramedullary Spinal Cord Abscess in Adults: A Systematic Review

BACKGROUND AND OBJECTIVES

Intramedullary spinal cord abscess (ISCA) was described 200 years ago but remains poorly understood and is often mistaken for immune-mediated or neoplastic processes. We present a systematic review of ISCA in adults, describing the clinical presentation, diagnostic features, treatment strategies, and outcomes.

METHODS

Database searches for intramedullary abscess were performed on April 15, 2019, and repeated on February 9, 2022, using PubMed and EMBASE with 2 unpublished cases also included. Publications were independently reviewed for inclusion by 2 authors followed by adjudication. Data were abstracted using an online form and then analyzed for predictors of disability.

RESULTS

A total of 202 cases were included (median age 45 years [interquartile range 31-58]; 70% male). Thirty-one percent of those affected had no identified predisposing condition. The most common symptom was weakness (97%), and the median symptom duration before presentation was 10 days (interquartile range 5-42). An MRI showed restricted diffusion in 100% of 8 cases where performed and enhancement in 99% of 153 cases where performed. The most common organisms were Mycobacterium tuberculosis (29%), Streptococcus sp. (13%), and Staphylococcus sp. (10%). All patients received antimicrobial therapy; surgical drainage was performed in 65%. At follow-up (median 6 months), 12% had died, 69% were ambulatory, and 77% had improved compared with clinical nadir. Of those who underwent operative intervention, surgery within 24 hours of diagnosis was associated with an increased likelihood of being ambulatory at follow-up compared with surgery after 24 hours (odds ratio 4.44; 95% CI 1.26-15.61; p = 0.020).

DISCUSSION

ISCA is important to consider in any patient presenting with acute-to-subacute, progressive myelopathy. Immunocompromise and typical signs of infection (e.g., fever) are often absent. Diffusion restriction and gadolinium enhancement on MRI seem to be sensitive. Antimicrobial therapy with surgical drainage is the most common therapeutic approach, but morbidity remains substantial. If performed, urgent surgery may be more beneficial.

Brain Abscess Due to Dental Sinusitis: A Case Report on Incomplete Infection Defense Associated With a Post-Fusion Linear Skull Fracture

Brain abscess is a pyogenic disease secondary to a bacterial, tuberculous, or fungal infection of the brain; thus, early detection and treatment are of crucial importance. Herein, we present a case of a brain abscess arising from dental sinusitis due to an incomplete infection defense mechanism linked to a post-fusion linear skull fracture. The patient initially presented with a persistent headache, which was diagnosed as frontal sinusitis. Consequently, antibiotic treatment was started. However, due to a refractory response to antibiotics, MRI was performed, which revealed a brain abscess in the frontal lobe adjacent to the right frontal sinus measuring 40 mm in diameter. This abscess was surgically drained and cultured. Initially, the patient was treated with three antibiotics, which were eventually de-escalated. The cultures revealed nasal commensal bacteria, suggesting a direct spillover from sinusitis leading to a brain abscess. A tooth with root inflammation, which had been left untreated and resulted in bone melting of the maxillary sinus wall, was extracted. After more than eight weeks of antimicrobial therapy, improvement in the clinical and imaging findings was noted, and the patient was discharged. Brain abscesses may develop from sinusitis even after linear fractures have healed due to a continued incomplete infection defense mechanism. Moreover, root and sinus infections should undergo evaluation, including the upper dental crown using coronal computed tomography, and treatment should be initiated promptly.

Peculiar Case of Brain Abscess Caused by Propionibacterium acnes in an Immunocompetent Individual Without Prior Neurosurgical Intervention: A Case Report and Literature Review

Propionibacterium acnes (P. acnes) is a slow-growing, anaerobic, gram-positive bacillus that commonly colonizes the skin and is a rare cause of CNS infections. It was previously viewed as a culture contaminant but is now recognized to infrequently cause indolent cases of CNS infections. It is even more rarely associated with abscesses in patients without a prior history of neurosurgical intervention. Due to being a slow-growing bacteria, P. acnes is frequently discovered to be the causative organism after 16S rRNA sequencing. In this case, the culture was positive. There are only five other reported cases of patients with a P. acnes abscess without prior neurosurgical intervention. Here we present the sixth case of an immunocompetent young male who was found to have a P. acnes brain abscess.

Treatment of septic encephalopathy and encephalitis - a critical appraisal

INTRODUCTION

The central nervous system is frequently involved during severe sepsis. Patients either develop septic encephalopathy characterized by delirium and coma or focal neurological signs as a consequence of septic-embolic or septic-metastatic encephalitis.

AREAS COVERED

In this review, a summary of currently available literature on established and some promising experimental treatment options for septic encephalopathy and encephalitis is provided, with a focus on the clinical utility of published studies.

EXPERT OPINION

Treatment relies on proper identification of the causative pathogen and rapidly initiated adequate empirical or (after identification of the pathogen) tailored antibiotic therapy, fluid and electrolyte management. In the presence of brain abscess(es) or mycotic aneurysm(s), surgery or interventional neuroradiology must be considered. Pharmacological approaches to prevent delirium of different etiology include the use of dexmedetomidine and (with limitations) of melatonin and its derivatives. In the absence of a specific pharmacological treatment, non-pharmacological bundles of interventions (e.g. promotion of sleep, cognitive stimulation, early mobilization and adequate therapy of pain) are of proven efficacy to prevent delirium of different etiology including sepsis. Experimental promising therapies include the use of non-bacteriolytic antibiotics and the reduction of the toxic effects of microglial activation.

Cryptogenic Pontine Abscess Treated With Stereotactic Aspiration: A Case Report

Brainstem abscesses are localized collections of pus or infected material within the brainstem, which can cause inflammation, tissue damage, and compression of adjacent structures. This can lead to a variety of symptoms, including headache, fever, and focal neurological deficits, among many others. Brainstem abscesses are potentially life-threatening and considered to be rare, and pontine abscesses are even rarer. Both are often caused by the spread of infection from nearby structures like the middle ear, sinuses, and mastoid air cells, but they can also result from distant infectious sites that have spread to the bloodstream. Ambiguous clinical presentation can delay appropriate care and lead to poorer outcomes. We present a rare case of pontine abscess in a 54-year-old male with both undetermined causal origins and unclear infectious signs, namely, the lack of fever, fatigue, and chills. We will discuss the etiologies, diagnosis, and treatment of cryptogenic brainstem lesions in this case report.

Multiple Abscesses in the Frontal, Temporal and Brainstem regions in a 4.5-year-Old Girl- An Illustrative Case Report

Background

Brainstem located abscesses are rare in the pediatric population. Diagnosis of brain abscess can be challenging as patients may present with nonspecific symptoms and the classical triad of headache, fever, and focal neurological deficit is not always present. Treatment can be conservative or a combination of surgical intervention with antimicrobial therapy.

Case Description

We present the first case of a 4.5-year-old girl with acute lymphoblastic leukemia that developed infective endocarditis (IE) and subsequently developed 3 suppurative collections (frontal, temporal, and brainstem). The patient had negative cerebrospinal, blood, and pus culture growth and subsequently underwent burr-hole drainage of the frontal and temporal abscesses with a 6-week course of intravenous antibiotic therapy with an uneventful postoperative course. At 1 year, the patient is left with minor right lower limb hemiplegia and no cognitive sequelae.

Conclusion

The decision to surgically intervene for brainstem abscesses is dependent on surgeon and patient factors including the presence of multiple collections, midline shift, the aim of source identification in sterile cultures, and the patient's neurological condition. Patients with hematological malignancies should be monitored closely for IE which is a risk factor for hematogenous spread of brainstem located abscesses.

Robot-Guided Stereotactic Puncture and Drainage in the Treatment of Thalamic Abscess

Brain abscess is rare in clinic, the reported incidence is only 0.4 to 0.90 per 100,000 population, and most of them have a history of prodromal infection. Headache and fever are the most common clinical symptoms, and only a few are accompanied by neurological disorders. For the treatment of brain abscess, the most commonly used treatment is stereotactic puncture drainage and antibacterial therapy. A patient with a left thalamic abscess with no history of prodromal infection was reported. Stereotactic puncture and drainage were performed under the guidance of the Ruimi robot. The bacterial culture of the abscess was Streptococcus constellation (Streptococcus constellatus). The patient was discharged after 4 weeks of antibacterial treatment with vancomycin. The patients were followed up half a year after the operation, the prognosis was good and there was no recurrence.

Clinical and radiological characteristics of brain abscess due to different organisms in hospitalized patients: A 6-year retrospective study from China

Background

Brain abscess (BA) is a rare but life-threatening infection. Early identification of the pathogen is helpful to improve the outcomes. This study aimed to describe the clinical and radiological features of patients with BA caused by different organisms.

Methods

A retrospective, observational study of patients with known etiologic diagnosis of BA in Huashan Hospital Affiliated to Fudan University in China between January 2015 and December 2020 was conducted. Data on patient demographics, clinical and radiological presenting features, microbiological results, surgical treatment, and outcomes were collected.

Results

Sixty-five patients (49 male, 16 female) with primary BAs were included. Frequent clinical presentations included headache (64.6%), fever (49.2%) and confusion (27.3%). Streptococcus viridans was associated with thicker wall of abscesses (6.94 ± 8.43 mm for S. viridans versus 3.66 ± 1.74 mm for other organisms, P = 0.031) and larger oedema (89.40 ± 15.70 mm for S. viridans versus 74.72 ± 19.70 mm for other organisms, P = 0.023). The independent factor associated with poor outcome identified by multivariate analysis was confusion (Odds ratio 6.215, 95% confidence interval 1.406-27.466; P = 0.016).

Conclusions

Patients with BAs caused by Streptococcus species had nonspecific clinical signs, but specific radiological features, which might be helpful for early diagnosis.

Recent Advances in Pharmaceutical Approaches of Antimicrobial Agents for Selective Delivery in Various Administration Routes

Globally, the increase of pathogenic bacteria with antibiotic-resistant characteristics has become a critical challenge in medical treatment. The misuse of conventional antibiotics to treat an infectious disease often results in increased resistance and a scarcity of effective antimicrobials to be used in the future against the organisms. Here, we discuss the rise of antimicrobial resistance (AMR) and the need to combat it through the discovery of new synthetic or naturally occurring antibacterial compounds, as well as insights into the application of various drug delivery approaches delivered via various routes compared to conventional delivery systems. AMR-related infectious diseases are also discussed, as is the efficiency of various delivery systems. Future considerations in developing highly effective antimicrobial delivery devices to address antibiotic resistance are also presented here, especially on the smart delivery system of antibiotics.

Cerebral abscesses with odontogenic origin: a population-based cohort study

Objectives

Recent studies have indicated that cerebral abscess (CA) patients with odontogenic origin are on the rise. However, CA patients are often poorly characterized and with an unknown etiologic background. The purpose of this study is to identify and characterize CA patients that may have an odontogenic origin based on microbiologic, radiographic, and/or clinical findings.

Materials and methods

This is a population-based cohort study analyzing retrospective and prospective data from CA patients. Radiographic examinations of panoramic radiographs (PRs) or computed tomography (CT) scans were conducted. CA patients characterized with odontogenic origin required the fulfilment of the following criteria on admission: (1) Oral pathologic conditions were the only bacterial infections present, (2) oral microorganisms were isolated in the purulent exudate from the brain, and (3) radiographically and/or clinical recordings of oral pathologic conditions.

Results

A total of 44 patients could be included in this study of which 25 (57%) were characterized as having CA with a likely odontogenic origin. Type two diabetes (T2D) (p = 0.014) and microorganisms of the Streptococcus anginosus group (SAG) (p < 0.01) were overrepresented in patients with CAs of odontogenic origin.

Conclusions

Odontogenic infections may cause CAs to a greater extent than previously assumed. T2D was overrepresented among patients with odontogenic CA. When microorganisms of the SAG were isolated from the brain pus, CA patients had a predisposing odontogenic or sinus infection.

Clinical relevance

The identification of patients with a likely odontogenic CA will contribute to understanding the etiology of the infectious disease and highlighting the importance of preserving oral health.

Bacterial Brain Abscess and Life-Threatening Intracranial Hypertension Requiring Emergent Decompressive Craniectomy After SARS-CoV-2 Infection in a Healthy Adolescent

Acute coronavirus 2 (SARS-CoV-2) infection usually results in mild symptoms, but secondary infections after SARS-CoV-2 infection can occur, particularly with comorbid conditions. We present the clinical course of a healthy adolescent with a brain abscess and life-threatening intracranial hypertension requiring emergent decompressive craniectomy after a SARS-CoV-2 infection. A 13-year-old healthy immunized male presented with invasive frontal, ethmoid, and maxillary sinusitis and symptoms of lethargy, nausea, headache, and photophobia due to a frontal brain abscess diagnosed three weeks after symptoms and 11 days of oral amoxicillin treatment. Coronavirus disease 2019 (COVID-19) reverse transcription-polymerase chain reaction (RT-PCR) was negative twice but then positive on amoxicillin day 11 (symptom day 21), when magnetic resonance imaging revealed a 2.5-cm right frontal brain abscess with a 10-mm midline shift. The patient underwent emergent craniotomy for right frontal epidural abscess washout and functional endoscopic sinus surgery with ethmoidectomy. On a postoperative day one, his neurological condition showed new right-sided pupillary dilation and decreased responsiveness. His vital signs showed bradycardia and systolic hypertension. He underwent an emergent decompressive craniectomy for signs of brain herniation. Bacterial PCR was positive for Streptococcus intermedius, for which he received intravenous vancomycin and metronidazole. He was discharged home on hospital day 14 without neurological sequelae and future bone flap replacement. Our case highlights the importance of timely recognition and treatment of brain abscess and brain herniation in patients with neurological symptoms after SARS-CoV-2 infection, even in otherwise healthy patients.

Systematic review of neuroparacoccidioidomycosis: The contribution of neuroimaging

BACKGROUND

Advanced neuroimaging demonstrated that neurological involvement occurs in up to 30% of paracoccidioidomycosis (PCM) cases. Current knowledge of neuroparacoccidioidomycosis (NPCM) is based on a 2009 systematic review. However, in the last decade, several new cases have been published, with modern neuroimaging techniques.

OBJECTIVES

We believe a new systematic review is needed to summarise these advances.

METHODS

We searched PubMed/MEDLINE, Embase and LILACS for studies from January 2010 to May 2022. Case series and case reports of NPCM were included. We performed a metaproportion to estimate a summary proportion with 95% confidence intervals (CI).

RESULTS

Thirty-four studies including 104 patients were evaluated. We combined our data with the results from the previous review that included 257 cases, totalling 361 patients. We found no new important demographic, clinical or laboratory characteristics. On magnetic resonance imaging (MRI), we found that 72% (95%CI: 38-91) had hyperintensity on T1-weighted image; 84% (95%CI: 71%-92%) had hypointensity on T2-weighted image; 80% (95%CI: 66-89) had contrast enhancement with the classical ring-enhancing pattern. All 8 patients undergoing spectroscopy presented lipid peaks. We found a 16% mortality, lower than in the previous review (44%).

CONCLUSION

NPCM presents a characteristic pattern on MRI that may help to differentiate it from other causes of single or multiple brain lesions. Albeit there is a frequent pattern, it is not specific, as other granulomatous diseases may show similar findings. Advances in neuroimaging with early diagnosis and appropriate management of the disease may have contributed to reducing its mortality.

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.

Neuroimaging Patterns of Intracranial Infections: Meningitis, Cerebritis, and Their Complications

Neuroimaging provides rapid, noninvasive visualization of central nervous system infections for optimal diagnosis and management. Generalizable and characteristic imaging patterns help radiologists distinguish different types of intracranial infections including meningitis and cerebritis from a variety of bacterial, viral, fungal, and/or parasitic causes. Here, we describe key radiologic patterns of meningeal enhancement and diffusion restriction through profiles of meningitis, cerebritis, abscess, and ventriculitis. We discuss various imaging modalities and recent diagnostic advances such as deep learning through a survey of intracranial pathogens and their radiographic findings. Moreover, we explore critical complications and differential diagnoses of intracranial infections.

Esophageal cancer presenting with brain abscess

A 76-year-old man experienced fatigue and progressive dysphagia. He underwent endoscopy at another hospital and was diagnosed with thoracic esophageal cancer. Three days after the endoscopy, the patient was rushed to our hospital with sudden seizures of the right upper and lower extremities. Contrast-enhanced computed tomography scan revealed a ring-shaped contrast-enhanced mass formation in the left parietal lobe with edema in the surrounding brain parenchyma. Contrast-enhanced magnetic resonance imaging showed a ring-shaped lesion with a high intensity on diffusion-weighted images. He was diagnosed with a brain abscess in the left parietal lobe. For abscess drainage, a quasi-emergent small craniotomy was performed. Culture of the drainage fluid revealed Streptococcus species and Haemophilus parainfluenzae. After 6 weeks of antibiotic therapy, the patient underwent a thoracoscopic esophagectomy. After the esophagectomy, there was no recurrence of the brain abscess for more than 2 years and only symptomatic epilepsy remained. Conclusively, although brain abscesses caused by esophageal cancer are rare, the possibility of brain abscess and metastasis should be considered when patients present with convulsions or higher brain disorders.

Neurological Emergencies in the Intensive Care Unit

Neurological emergencies carry significant morbidity and mortality, and it is necessary to have a multidisciplinary approach involving the emergency physician, the neurologist, the intensivist, and the critical care nursing staff. These disorders can be broadly divided into noninfectious and infectious etiologies. In this article, we review a few of the neurological emergencies that present to the neurological intensive unit, with emphasis on convulsive status epileptics, myasthenia gravis, Guillain-Barré syndrome, meningitis, encephalitis, and brain abscess.

Invasive procedures and risk of brain abscess: a nationwide, population-based case-control study

OBJECTIVES

It is unknown whether invasive procedures are associated with brain abscess.

METHODS

Nationwide, population-based, matched case-control study of patients with culture verified brain abscess in Denmark from 1989 to 2016. Exposure was invasive procedures 0-6 months before study inclusion.

RESULTS

We identified 435 patients and 3909 controls. The level of comorbidity was higher among patients with brain abscess than among controls. A total of 48 cases (11%) had one or more invasive procedures 0-6 months before study inclusion (adjusted odds ratios (aOR) of 3.6 (95% confidence interval (CI): 2.5-5.1), a population attributable fractions of 8% (95% CI: 7-9)). In primary care, ear, nose and throat (ENT) procedures were associated with brain abscess (aOR of 4.0 (95% CI: 2.0-8.0)), but gastrointestinal endoscopies were not (aOR of 1.0 (95% CI: 0.3-3.2)). No bronchoscopies were performed in primary care. In the hospital-based setting, ENT procedures, bronchoscopies and gastrointestinal endoscopies were associated with an increased risk of brain abscess (aOR of 14.5 (95% CI: 4.8-43.8), 20.3 (95% CI: 3.8-110.1) and 3.4 (95% CI: 2.0-5.6), respectively).

CONCLUSIONS

The association between invasive procedures and brain abscess was more pronounced in the hospital-based setting than in primary care.

Experimental animal models for brain abscess: a systematic review

BACKGROUND

Brain abscess (BA) is a rare, but severe infection and experimental BA animal models may prove crucial for advances in treatment. This review describes the development of experimental BA models and the clinical advances obtained from these, in a historical perspective.

MATERIAL AND METHODS

Experimental BA studies from inception until June 15, 2022, were included by searching the PubMed and Embase databases. Inclusion required the use of an experimental BA animal model. Non-bacterial BA models, in vitro studies, veterinarian case-reports, and articles written in non-English language were excluded. Bias was not systematically assessed, and the review was not registered at the PROSPERO.

RESULTS

79 studies were included. The majority of animal BA models have been based on small rodents using Staphylococcus aureus. The models have delineated the natural development of BA and provided detailed descriptions of the histopathological characteristics consisting of a necrotic centre surrounded by layers of inflammatory cells and fibroblasts encapsulated by a dense collagenous layer. Radiological studies of animal BA have been shown to correlate with the corresponding stages of human BA in both computed tomography and magnetic resonance imaging and may guide diagnosis as well as the timing of neurosurgical intervention. Moreover, pharmacokinetic studies of the intracavitary penetration of various antimicrobials have helped inform medical treatment of BA. Other studies have examined the diverse effects of corticosteroids including decreased cerebral oedema, intracranial pressure, and intracavitary drug concentration, whereas concerns on decreased or weakened capsule formation could not be confirmed. Finally, studies on the immunological response to BA have highlighted potential future immunomodulatory targets.

CONCLUSIONS

Animal models have been vital for improvements in the management of BA. Experimental BA models resembling human disease including polymicrobial infection by oral cavity flora in large animals are needed.

Retrospective review of the epidemiology, microbiology, management and outcomes of intra-cranial abscesses at a neurosurgical tertiary referral centre, 2018-2020

BACKGROUND

Intracranial abscesses are rare but serious, and are associated with significant morbidity and mortality. Due to both the rarity and severity of these infections, well-controlled trials have not been reported in the literature, and optimal management is a matter for expert opinion. Advances in surgical management have improved outcomes and increased rates of microbiological diagnosis. However, the approach to antimicrobial chemotherapy varies considerably, including the choice of antibiotic, the duration of treatment, and the timing of oral switch.

METHODS

We conducted a retrospective review of 43 cases of intracranial abscesses from a large, tertiary neurosurgical centre in London, UK, between 2018 and 2020, including 29 primary intra-parenchymal abscesses, 11 subdural abscesses and 3 extradural abscesses.

RESULTS

The majority of cases had surgical intervention; 6/43 (14%) required repeat intervention (all intra-parenchymal abscesses). A microbiological diagnosis was made in 83% of cases. Intravenous antibiotics were given for a median of 33 days (IQR 23-44 days), with a variable duration of oral follow-on antibiotics. Total duration of antibiotic treatment ranged from 0 to 467 days. Only three patients from our cohort are known to have died.

CONCLUSION

Shorter courses of intravenous antibiotics for brain abscesses were not associated with increased mortality. In the absence of well-controlled trials, a national registry of intracranial abscesses would provide invaluable data to inform optimal treatment.

Surgical management of an abscess of the insula

Background

Mass lesions within the insular are diagnostically and surgically challenging due to the numerous critical cortical, subcortical, and vascular structures surrounding the region. Two main surgical techniques - the transsylvian approach and the transcortical approach - provide access to the insular cortex. Of the range of pathologies encountered, abscesses in the insula are surprisingly rare.

Case Description

A 34-year-old patient was admitted for surgical resection of a suspected high-grade glioma in the insula of the dominant hemisphere. A rapid clinical decline prompted emergent neurosurgical intervention using a transsylvian approach. Surprisingly, abundant purulent material was encountered on entering the insular fossa. Pathological analysis confirmed an insular abscess, although a source of infection could not be identified. The patient required a second evacuation for reaccumulation of the abscess and adjuvant corticosteroids for extensive cerebral edema.

Conclusion

An abscess located in the insular cortex is an incredibly rare occurrence. Surgical management using the transsylvian approach is one option to approach this region. Familiarity with this approach is thus extremely beneficial in situations requiring emergent access to the dominant insula when awake mapping is not feasible. In addition, treatment of abscesses with adjuvant corticosteroids is indicated when extensive, life-threatening cerebral edema is present.

Surgical aspiration versus excision for intraparenchymal abscess: a systematic review and Meta-analysis

Brain abscesses are associated with considerable morbidity and mortality, requiring timely intervention to achieve favourable outcomes. With the advent of high-resolution computed tomography (CT) imaging, mortality following both aspiration and excision of brain abscesses has improved markedly. As a result, there has been a marked shift in neurosurgical practice with aspiration eclipsing excision as the favoured first-line modality for most abscesses. However, this trend lacks sufficient supporting evidence, and this systematic review and meta-analysis seeks to compare aspiration and excision in the treatment of brain abscess. Twenty-seven studies were included in the systematic review, and seven comparative papers in meta-analysis. Aspiration was the chosen technique for 67.5% of patients. Baseline characteristics from the studies included only in the systematic review demonstrated that abscesses treated by aspiration were typically larger and in a deeper location than those excised. In the meta-analysis, we initially found no significant difference in mortality, re-operation rate, or functional outcome between the two treatment modalities. However, sensitivity analysis revealed that excision results in lower re-operation rate. On average, the included studies were of poor quality with average Methodological Index for Non-Randomized Studies (MINORS) scores of 10.3/16 and 14.43/24 for non-comparative and comparative papers respectively. Our study demonstrates that excision may offer improved re-operation rate as compared to aspiration for those abscesses where there is no prior clinical indication for either modality. However, no differences were found with respect to mortality or functional outcome. Evidence from the literature was deemed low quality, emphasizing the need for further investigation in this field, specifically in the form of large, well-controlled, comparative trials.

Rare brain and pulmonary abscesses caused by oral pathogens started with acute gastroenteritis diagnosed by metagenome next-generation sequencing: A case report and literature review

Odontogenic brain and pulmonary abscesses are extremely rare infectious diseases. It is mainly caused by the upward or downward transmission of local infection or blood-borne spread. In recent years, with the wide application of some novel testing methods in clinical practice, the diagnosis of unexplained infections such as odontogenic abscesses in different organs has gradually become clear. We report a case of a 21-year-old male who was healthy and had not received any oral treatment before onset. He started with acute gastroenteritis-related symptoms, then developed meningitis-related symptoms seven days later with septic shock. No obvious abscess lesions were found on head computed tomography (CT) at admission, and the etiology was not clear by routine examination, which was very easy to misdiagnose as a serious infection caused by intestinal pathogens. But odontogenic pathogens were found both in his blood and cerebrospinal fluid through metagenomic next-generation sequencing (mNGS) analysis. Subsequently, rechecked imaging examination displayed multiple brain and pulmonary abscesses. Finally, it was diagnosed as an odontogenic brain and pulmonary abscess. After an extremely lengthy anti-infection course (13 weeks of intravenous antibiotics plus 2 weeks of oral antibiotics) and surgery, the patient was improved and discharged from the hospital. From this case, we could see that the development of new diagnostic technologies such as mNGS plays an important role in the early and confirmed diagnosis of diseases previously difficult to diagnose such as odontogenic polymicrobial infections and ultimately helps to improve the prognosis of these patients.

Retrospective Review of the Clinical Outcomes of Surgically Managed Patients with Intracranial Abscesses: A Single-Center Review

OBJECTIVE

This study analyzed patient, radiologic, and clinical factors associated with operative brain abscesses and patients' functional outcomes.

METHODS

A retrospective analysis was conducted of neurosurgical cases of brain abscesses from 2009 to 2019 at a Canadian center. Functional outcome was recorded as Modified Rankin Scale score and Extended Glasgow Outcome Scale score. Multivariate analysis was conducted to identify relevant prognostic factors.

RESULTS

We identified 139 patients managed surgically for brain abscesses. Resection alone was performed in 64% of patients, whereas 26.6% underwent aspiration alone. Most were adults (93.2%) and male (68.3%). Immunocompromise risk factors included diabetes (24.5%), cancer (23.7%), and immunosuppressive therapy (11.5%). Likely sources were postoperative (17.3%), systemic spread (16.5%), and poor dentition (12.9%). Microorganisms cultured from abscess samples were mixed growth (28%), Streptococcus anginosus (24.5%), and Staphylococcus aureus (7.9%). Disposition was home (42.4%) or repatriation to a home hospital (50.4%). By Extended Glasgow Outcome Scale, 25.2% had an unfavorable outcome including a mortality of 11.5%. Factors on multivariate analysis associated with poor outcome included diabetes (odds ratio, 2.8; 95% confidence interval [CI], 1.2-5.0) and ventricular rupture (odds ratio, 5.0; 95% CI, 1.7-13.5; hazard ratio, 12; 95% CI, 3.9-37.0). Supratentorial superficial eloquently located abscess was also associated with poor outcome (hazard ratio, 5.5; 95% CI, 1.8-16.7). Outcomes were similar with surgical excision and aspiration.

CONCLUSIONS

Ventricular rupture and diabetes are significant risk factors for poor outcomes in intraparenchymal brain abscesses. No clear difference in outcomes was found between surgical excision or aspiration in our retrospective cohort.