Brain abscess: clinical aspects of 100 patients

Otogenic Cerebellar Abscess with Polymicrobial Anaerobic Infection in a Young Female- A Rare Presentation

Brain abscess is a serious clinical condition caused by a localized collection of pus within the brain tissue. This typically occurs as a result of an infection that originates from a nearby area, such as an ear, sinus, or dental infection, or an infection in the bloodstream. Streptococcus and Staphylococcus species are the most common organisms implicated in brain abscesses. Apart from aerobic growth, cases of mixed infections of both aerobic and anaerobic organisms are also commonly reported in the literature. Herein we report a 23-year-old immunocompetent female with chronic otitis media who presented with cerebellar abscess where the aerobic growth was sterile and anaerobic culture revealed pure growth of dual anaerobes viz… Peptostreptococcus and Bacteroides thetaiotaomicron. This case highlights the importance of prompt diagnosis and management of polymicrobial anaerobic infection in cases of brain abscess.

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.

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.

An Eight Year Clinico-Microbiological Retrospective Study on Brain Abscesses in India

Background:

Intracranial abscesses have been a diagnostic and therapeutic challenge since time immemorial for both the microbiologists and the neurosurgeons. There is paucity of detailed studies documenting the infecting organism causing brain abscesses in South India.

Aims:

The study aimed at identifying and assessing the prevalence of aerobic, anaerobic bacteria and fungi associated with brain abscesses at a tertiary care hospital in South India.

Methods and Material:

Eight years data was collected from the records of culture reports from 2007 to 2010 and 2013 to 2018. The corresponding clinical case records were retrieved for the assessment of risk factors. Risk factors of brain abscess development were assessed based on clinical cases records.

Results:

Data from 140 brain abscess cases obtained over a period of 8 years were analyzed. Out of the 140 samples, 66 (47.14%) were culture positive in which 33 (50%) had single aerobic/facultative anaerobic bacteria, 20 (30.3%) had mixture of more than one aerobic/facultative anaerobic bacteria, 12 (18.18%) had single obligate anaerobic bacteria and 1(1.5%) sample had Mycobacterium tuberculosis isolated. Among the total 92 isolates, Pseudomonas aeruginosa (21/92, 23%) and Staphylococcus aureus (20/92, 22%) predominated. Bacteroides fragilis group was the most common obligate anaerobe isolated. There were no fungal isolates. As there were various isolates isolated, hence there is heterogeneity of isolates detected Neuroanatomically, parietal lobe (45/140, 32%) was the most common location. Otogenic infection was the major risk factor for parietal and temporal lobe abscess (P value < .05).

Conclusions:

It has become essential for the microbiologists to be aware of unusual isolates from brain abscess and its complex nature. Obscurity and difficulty in their microbiological diagnosis calls for more such detailed studies.

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.

Bacterial Brain Abscess: An Outline for Diagnosis and Management

Despite advances in the diagnosis and management of brain abscess, significant associated morbidity and mortality remain high. We retrospectively reviewed adults who presented with pyogenic brain abscess from January 1, 2009, through June 30, 2020. Overall, 247 patients were identified. The median age was 59 years, and 33.6% had a history of head and neck surgery or traumatic brain injury. Diagnostic brain magnetic resonance imaging (MRI) was performed in the bulk (93.1%) of patients. A total of 205 patients (83%) were managed with medical and surgical treatment. The most common definitive antibiotic regimen was monotherapy (48.2%). The median duration of antimicrobial therapy was 42 days. Compared with those who received combined therapy, patients with medical therapy alone had a higher mortality rate (21.4% vs 6%; P =. 003) with more neurologic sequelae (31% vs 27.1%; P = .5). Most patients with brain abscesses are older with multiple underlying comorbidities, and one-third had antecedent head and neck surgery. A prompt combined surgical and medical approach with prolonged antimicrobial therapy may cure the infection with avoidance of permanent residual neurologic deficits.

Intracranial infected collections and epidemiology in the top end, Northern Territory, Australia. A 10-year case series

BACKGROUND

The incidence of intracranial infected collections (IIC) ranges between 0.4 and 1.2/100 000 persons per year. There is anecdotal evidence that residents in Top End of the Northern Territory are at a greater risk of infections with protracted clinical presentations. To our knowledge, there is no study to date to explore IIC in the Top End.

METHODS

Retrospective observational analysis of IIC in the Top End, Northern Territory, Australia from 2009 to 2019. International classification of disease code G06 was used to identify cases diagnosed at Royal Darwin, Gove District and Katherine Hospital with no restriction of age or gender.

RESULTS

A total of 51 cases were identified. This equated to an incidence of 2.9 (95% CI 2.2-3.8) in 100 000 PPY. When separated into Indigenous and non-Indigenous populations, the respective incidences were 8.65 (95% CI 6.2-12.1) and 1.1 (95% CI 0.7-1.9) in 100 000 PPY. The Indigenous population was at a significantly higher risk of IIC compared with non-Indigenous Australians with a relative risk of 7.3 (P < 0.0001 95% CI 4.0-13.3). The most common aetiology was otogenic infections with all cases being identified in the Indigenous population. Comparison of other clinical parameters between the two populations were not statistically significant.

CONCLUSIONS

Within the limitations of a retrospective study, the incidence of IICs is higher in the Top End than reported elsewhere in the literature. This is particularly true for the Indigenous population.

Brain Abscess Apparent Diffusion Coefficient is Associated With Microbial Culture Yields

BACKGROUND

Obtaining pus for microbial cultures is one of the surgical aims in patients with brain abscess. Predictors of microbial yields are necessary as they help in treatment planning.

PURPOSE

To investigate the relationship between microbial culture yields of brain abscesses and their apparent diffusion coefficient (ADC) values and clinical characteristics.

STUDY TYPE

Retrospective.

SUBJECTS

Eighty-four patients diagnosed with brain abscess by surgery and histopathology (59 with positive abscess cultures).

FIELD STRENGTH/SEQUENCE

Diffusion-weighted, T2-weigthed, and contrast-enhanced T1-weighted imaging at 1.5 T and 3 T.

ASSESSMENT

Contrast-enhanced T1-weighted images were co-registered to ADC maps. Three neuroradiologists determined abscess imaging characteristics (distribution, location, and ventricular rupture), and two measured abscess volumes and ADC values. Clinical characteristics collected included sex, age, fever, underlying diseases, infection sources, white blood cell count, percentage of segmented neutrophils, C-reactive protein level, regimen and duration of empirical antibiotics, and types of surgery.

STATISTICAL TESTS

Interobserver differences were assessed with Fleiss kappa and intraclass correlation coefficients. The differences in clinical and imaging factors between the positive and negative culture groups were compared with Chi-square analysis or Student's t test. All factors were subjected to multivariable logistic regression analysis to assess their associations with microbial culture yields, and factors with statistical significance were evaluated with receiver operating characteristic curve analysis to assess their diagnostic performance in discriminating the two groups.

RESULTS

Mean ADC (×10^-6  mm² /s) of culture-negative abscesses (841 ± 173) was significantly higher (P < 0.05) than that of culture-positive abscesses (536 ± 90). On multivariable analysis, mean ADC was the only significant factor (P < 0.05) related to culture yields. With 660 as the cutoff value, the sensitivity, specificity, and accuracy of ADC for discriminating culture yields were 93.2%, 88.0%, and 91.7%, respectively.

DATA CONCLUSION

ADC could be used to discriminate between culture-positive and culture-negative abscesses.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 2.

HIV, Tuberculosis, and Otogenic Intracranial Sepsis: A Devastating Disease With a Subtle Presentation

OBJECTIVES

To undertake a large-scale review of otogenic intracranial sepsis in an area of highly prevalent HIV and tuberculosis (TB) to re-examine and inform early diagnosis and treatment efforts.

METHODS

Seventy-seven consecutive cases of otogenic intracranial sepsis in KwaZulu-Natal, South Africa were reviewed for demographics, presentation, imaging, HIV status, culture results, and outcomes.

RESULTS

The most common intracranial complications were intracranial abscess (46.8%), hydrocephalus (31.2%), subdural empyema (28.6%), and epidural empyema (26.0%). Ear discharge (87.0%), postauricular abscess (29.9%), and hearing loss (29.9%) were notable presenting symptoms. Overall mortality was 15.6%. Of the 45.5% of patients with HIV testing, 54.2% were HIV+, Mortality among HIV+ patients was 15.8% but only 6.3% in HIV- patients (p = 0.61, OR = 2.8). Eight patients (10.4%) had culture or histological evidence of TB infection.

CONCLUSIONS

Otogenic intracranial complications continue to present late and are associated with significant mortality and morbidity, despite advances in diagnostic and treatment modalities. This study represents one of the largest case-series in the literature, and the first to specifically evaluate the effects of HIV and TB infection.Patient presentation and severity of illness varied; however, a majority of patients presented with ear discharge and no focal neurological signs. An effect size for higher mortality among HIV+ patients compared with HIV- patients was noted but was not significant. Tuberculosis infection was prevalent compared with previous studies.This study reinforces the need for enhanced screening and early treatment of ear disease to minimize associated mortality and morbidity, particularly in immunocompromised patients.

Outcome of management of brain abscess in children

Objective

To find out the outcome of management of brain abscess in children.

Methods

This is prospective observational study conducted in the Department of Paediatric Neurosurgery at Children's Hospital and Institute of Child Health, Multan from July 2014 to June 2017. Children up to the age of 14 years suffering from brain abscess were admitted. After taking clinical history, general and systemic physical examination and necessary investigations, abscess was evacuated and abscess wall excised after performing craniotomy. Data was collected on a predesigned performa. Results were analyzed and compared with national and international literature through statistical package for social sciences (SPSS-20).

Results

Twenty five patients up to 14 years of age were included. Seventeen (68%) were male and eight (32%) female. Fever and vomiting were present in all 25 (100%) patients. Paranasal sinusitis was predisposing causative factor in 9(36%) followed by otitis media in 7 (28%). Abscess was present in frontal lobe in 9 (36%), temporoparietal region in 8 (32%), posterior fossa in 5 (20%) and multiple abscesses in 3 (12%). Craniotomy was performed, pus evacuated and abscess wall excised in all 25 (100%) patients. Three (12%) patients expired.

Conclusion

Incidence of brain abscess can be decreased by treatment of its predisposing causes as sinusitis and otitis media. Small abscess less than 2cm can be treated with antibiotics. Complete evacuation of pus and excision of abscess wall after performing craniotomy along with appropriate antibiotics is gold standard management of brain abscess in children.

Clinical features, microbiology, and management of pediatric brainstem abscess

PURPOSE

Brainstem abscess is a rare condition accounting for merely 1% of brain abscesses incidence in the pediatric population. This study aimed to present a single patient with a pontine abscess and review the literature to highlight clinical features, diagnosis, and management of brainstem abscess.

METHODS

The PubMed database was screened for English-language articles concerning pediatric brainstem abscess. We, therefore, identified 22 publications, which concisely depict 23 cases. Our study reports on the 24th pediatric patient diagnosed with that entity. All included reports were analyzed in terms of clinical presentation, diagnosis, management, and outcomes of described patients.

RESULTS

There was slight women predominance (15:9), with a mean age of occurrence 6.4 years, ranging from 7 months to 16 years. Pons was the most common location of brainstem abscess, occurring in 75% of patients. Clinically, they mostly presented with cranial nerves palsy (79.2%), hemiparesis (66.7%), and pyramidal signs (45.8%). The classic triad of symptoms, including fever, headache, and the focal neurologic deficit was present in 20.8% of patients. Positive pus cultures were obtained in 61.1%. Streptococci and Staphylococci were the most frequently identified pus microorganisms. Outcomes were satisfactory, with a 79.2% rate of general improvement.

CONCLUSIONS

Neurosurgical aspiration is a safe and beneficial therapeutic method. It should always be considered and should promptly be performed when the conservative treatment is not successful and clinical deterioration occurs. Prognosis in pediatric brainstem abscess is generally favorable. Most patients recover with minor neurologic deficits or improve completely.

Iatrogenic cerebral abscess leading to resolution of severe delusional disorder

A cerebral abscess (focal infection of brain parenchyma) carries a high mortality and morbidity. Iatrogenic cerebral abscesses are less common and make up 10% of all cases. The presence of a cerebral abscess can rarely improve a patient's prognosis and quality of life, however this case illustrates an abscess and its treatment following a prolonged course of antibiotics leading to resolution of a severe psychotic disorder. This is a case report of a 32-year-old female inpatient at a psychiatric hospital with a long-standing history of congenital hydrocephalus, cerebral palsy and organic delusional disorder who developed an iatrogenic cerebral abscess after insertion of an implantable intracranial pressure monitoring device. After receiving treatment of 6 weeks of intravenous meropenem the patient's mental condition rapidly improved, she became stable and euthymic and was discharged home. The patient has since had no delusions or hallucinations and is living independently at home.

Filifactor alocis brain abscess identified by 16S ribosomal RNA gene sequencing: A case report

We report a clinical case of Filifactor alocis brain abscess in an 85-year-old man who had decayed teeth 1 week prior. In this case, the abscess was surgically drained after empirical antibiotics had been initiated. Although the causative organism could not be identified by culture, F. alocis was detected via 16S ribosomal RNA (16S rRNA) gene sequencing of the pus isolated from the abscess. The patient recovered without serious sequelae after surgical drainage and prolonged antibiotic treatment, including metronidazole, ceftriaxone and meropenem for 8 weeks. The findings in this case emphasize that 16S rRNA gene sequencing allows bacterial diagnosis of brain abscess when phenotypic identification fails, such as in cases where patients are undergoing antimicrobial treatment at the time of sampling or where patients are infected with fastidious organisms.

Clinical characteristics and course of primary brain abscess

BACKGROUND

Due to improved diagnostic methods, the incidence of brain abscess is still rising. Therefore, clear and evidence-based therapy for the patients who suffer from brain abscesses is necessary. Brain abscesses are potentially life-threatening conditions that possibly lead to permanent injuries even after sufficient healing has taken place. The aims of this study were to analyze the clinical aspects of patients with brain abscesses and thereby to reveal the relevant aspects for the future treatment of the brain lesions.

METHODS

We retrospectively identified 47 patients (24 male, 23 female) who had received surgery or undergone the frameless stereotactic drainage of brain abscesses in our center from March 2009 to May 2017. We analyzed the clinical characteristics of the patients, as well as comorbidities and outcomes.

RESULTS

The mean age was 58 (range 7 to 86). Focus identification was successful in 28 patients (60%), with the most frequent causes of brain abscesses including the following: sinusitis (25%), dental infections (25%), and mastoiditis (21%). The mean Charlson Comorbidity Index was 1.57. Among the patients, 34% showed immunosuppressive conditions. We performed 1.5 surgeries per patient (53% via craniotomy, 28% biopsies or stereotactic drainage, 19% both procedures), followed by antibiotic treatment for 6.5 weeks (mean). In 30% of patients, no bacteria could be isolated. During the follow-up period (a median of 12 months), 23.4% of the patients died. The mortality rate during the initial hospital stay was 4.3%.

CONCLUSION

One third of the patients with brain abscesses showed immunosuppressive conditions, whereas brain abscesses also often occur in patients with good medical conditions. The isolation of the focus of infection is often possible. Surgical procedures showed very good outcomes. Patients over 60 years showed significantly worse clinical outcomes.

Management of brain abscesses: where are we now?

INTRODUCTION

Brain abscesses affect all age groups and are not peculiar to a particular country, race, or geographical location. It is a disease that, in the past, carried a high morbidity and mortality. With improvements in medical technology and expertise, outcomes have improved tremendously. The causative organisms vary vastly and have evolved with time. Treatment of brain abscesses is primarily with antimicrobial therapy but surgery plays a vital role in achieving better outcomes.

CONTENT

In this article, we review the literature to find out how the epidemiology of this disease has changed through the years and re-visit the basic pathological process of abscess evolution and highlight the new research in the biochemical pathways that initiate and regulate this process. We also highlight how magnetic resonance imaging and its various modalities have improved diagnostic accuracy. Finally, we discuss the pros and cons of traditional open surgery versus newer minimally invasive methods.

Pyogenic brain abscess and subdural empyema: presentation, management, and factors predicting outcome

PURPOSE

To describe the presentation and management of bacterial brain abscess and subdural empyema in adults treated at two tertiary centers. In addition, to identify factors that may predict a poor clinical outcome.

METHODS

A retrospective analysis of data obtained from clinical records was performed, followed by multivariate regression analysis of patient and treatment-related factors.

RESULTS

113 patients were included with a median age of 53 years and a male preponderance. At presentation symptoms were variable, 28% had a focal neurological deficit, and 39% had a reduced Glasgow coma scale (GCS). Brain abscesses most frequently affected the frontal, temporal, and parietal lobes while 36% had a subdural empyema. An underlying cause was identified in 76%; a contiguous ear or sinus infection (43%), recent surgery or trauma (18%) and haematogenous spread (15%). A microbiological diagnosis was confirmed in 86%, with streptococci, staphylococci, and anaerobes most frequently isolated. Treatment involved complex, prolonged antibiotic therapy (> 6 weeks in 84%) combined with neurosurgical drainage (91%) and source control surgery (34%). Mortality was 5% with 31% suffering long-term disability and 64% achieving a good clinical outcome. A reduced GCS, focal neurological deficit, and seizures at presentation were independently associated with an unfavorable clinical outcome (death or disability).

CONCLUSIONS

Complex surgical and antimicrobial treatment achieves a good outcome in the majority of patients with bacterial brain abscess and subdural empyema. Factors present at diagnosis can help to predict those likely to suffer adverse outcomes. Research to determine optimal surgical and antibiotic management would be valuable.

Dexamethasone Administration and Mortality in Patients with Brain Abscess: A Systematic Review and Meta-Analysis

BACKGROUND

Dexamethasone has been used to treat cerebral edema associated with brain abscess. Whereas some argue that dexamethasone might aid antibiotic treatment, others believe that because of its immunosuppressive characteristics, it might have a negative impact on outcomes. How corticosteroid use affects overall mortality of brain abscess patients remains unclear.

METHODS

A systematic search of the literature was conducted in accordance with PRISMA guidelines. PubMed, Embase, and Cochrane databases were utilized to identify all studies related to patients diagnosed with a brain abscess treated with dexamethasone. The main outcome of interest was mortality. Pooled effect estimates were calculated using fixed-effects (FE) and random-effects (RE) models.

RESULTS

After removal of duplicates, 1681 articles were extracted from the literature of which 11 were included. These included 7 cohort studies and 4 case series. Indications to administer dexamethasone were either hospital brain abscess protocol or clinical presentation of cerebral edema. The 7 cohort studies involving 571 patients with brain abscesses comprised of 330 patients treated with standard of care (SOC) plus dexamethasone and 241 patients treated with SOC alone, after aspiration or surgical management of the abscess in either group. Pooling results from all seven cohort studies demonstrated a nonsignificant mortality benefit comparing SOC and dexamethasone patients to SOC patients (FE: risk ratio [RR], 0.94; 95% confidence interval [CI], 0.64-1.37; RE: RR, 0.95; 95% CI, 049-1.82; I² = 53.9%; P for heterogeneity = 0.04).

CONCLUSIONS

In patients with a brain abscess treated with antibiotics, the use of dexamethasone was not associated with increased mortality.

Streptococcus Intermedius Brain and Diverticular Abscesses After Dental Manipulation: A Case Report

A brain abscess is defined as a focal intracerebral infection consisting of an encapsulated collection of pus, which can be a life-threatening complication of infections, trauma, or surgery. While immunocompromised patients can have a wide array of causative organisms, bacterial species represent the most common etiology in immunocompetent individuals. The incidence of brain abscesses ranges from 0.4 to 0.9 per 100,000, with a high predisposition among immunocompromised patients and in those with disruption of the blood-brain barrier.

The most common causative organisms found were Streptococcus species, particularly S. viridians and S. pneumonia, Enterococcus, and Staphylococcus species, mainly S. aurieus and S. epidermidis. Microorganism can invade the brain through different mechanisms, either directly by contiguous spread and odontogenic infections, which usually cause a single brain abscess, or indirectly through hematogenous spread which can cause multiple brain abscesses. Both surgical and conservative dental procedures contribute to hematogenous spreading of oral microorganisms. Although most of those organisms are eliminated shortly after they gain access to the bloodstream, some can persist and contribute to the pathogenesis of abscesses in the appropriate environment. Odontogenic origins are rarely implicated in the formation of brain abscesses, and oral foci comprise approximately 5% of identified cases. We report a case of brain and diverticular abscesses due to S. intermidius occurring two months after dental extraction. This case highlights the fact that even usual dental workup can result in the development of bacteremia and disseminated abscesses including but not restricted to the brain. Consequently, in addition to identifying the possible source of bacteremia with an extensive history and physical exam, the diagnosis of Streptococcus milleri organisms should prompt the physicians to screen for sites of possible metastatic infection spread.

Esophageal Squamous Cell Carcinoma Presenting with Streptococcus intermedius Cerebral Abscess

Background

Cerebral abscess is caused by inoculation of an organism into the brain parenchyma from a site distant from the central nervous system. Streptococcus intermedius (S. intermedius) is a commensal organism that is normally present in the aerodigestive tract and was reported to be the cause of brain abscesses after esophageal dilatation or upper endoscopy.

Case Presentation

We report the case of a 53-year-old female who presented with hematemesis and melena followed by left-sided weakness. Initially, her hemiplegia was found to be secondary to a right thalamic brain abscess caused by S. intermedius. Investigations led to the diagnosis of a mid-esophageal squamous cell carcinoma. We hypothesize that the cause of the abscess with this bacterium that naturally resides in the digestive tract and oral cavity is secondary to hematogenous spread from breach in the mucosal integrity from ulceration due to the cancer.

Conclusion

To our knowledge, our case is the first in the literature to describe a brain abscess caused by S. intermedius in association with a previously undiagnosed esophageal squamous cell carcinoma without any prior esophageal intervention.

Expressive aphasia caused by Streptococcus intermedius brain abscess in an immunocompetent patient

Background

Brain abscess is an uncommon but life-threatening infection. It involves a focal, intracerebral infection that begins in a localized area of cerebritis and develops into a collection of pus, surrounded by a well-vascularized capsule. Brain abscess still poses a significant problem in developing countries but rarely in developed countries. Predisposing factors vary in different parts of the world. With the introduction of antibiotics and imaging studies, the mortality rate has decreased between 5% and 15%. If left untreated it may lead to serious neurologic sequelae. The temporal lobe abscess can be caused by conditions like sinusitis, otitis media, dental infections, and mastoiditis if left untreated or partially treated. Additionally, in neurosurgical procedures like craniotomy, the external ventricular drain can get infected, leading to abscess formation.

Case presentation

We present the case study of an elderly female patient who presented with expressive aphasia caused by brain abscess, secondary to Streptococcus intermedius infection. The 72-year-old female with a medical history of hypertension came to hospital for evaluation with word-finding difficulty, an expressive aphasia that began a few days prior to presentation. Computed tomography of the head showed a left temporal lobe mass-like lesion, with surrounding vasogenic edema. The patient was empirically started on courses of antibiotics. The next day, she was subjected to magnetic resonance imaging of the brain, which showed a left temporal lobe septated rim-enhancing mass lesion, with bright restricted diffusion and diffuse surrounding vasogenic edema consistent with abscess. The patient was also seen by the neurosurgery department and underwent stereotactic, left temporal craniotomy, with drainage, and resection of abscess. Tissue culture grew S. intermedius sensitive to ampicillin sulbactam. Subsequently her expressive aphasia improved.

Conclusion

Brain abscess has a high mortality, however a significant proportion of patients with appropriately treated abscess recover completely and can survive without significant neurologic damage. Advanced imaging modalities may yield more accurate methods of differentiation of mass lesions in the brain. Biopsy of brain lesion with early initiation of appropriate antibiotics will change the outcome.

Hyperbaric oxygen therapy in spontaneous brain abscess patients: a population-based comparative cohort study

BACKGROUND

There is a need to improve outcome in patients with brain abscesses and hyperbaric oxygen therapy (HBOT) is a promising treatment modality. The objective of this study was to evaluate HBOT in the treatment of intracranial abscesses.

METHOD

This population-based, comparative cohort study included 40 consecutive adult patients with spontaneous brain abscess treated surgically between January 2003 and May 2014 at our institution. Twenty patients received standard therapy with surgery and antibiotics (non-HBOT group), while the remaining 20 patients also received adjuvant HBOT (HBOT group).

RESULTS

Resolution of brain abscesses and infection was seen in all patients. Two patients had reoperations after HBOT initiation (10 %), while nine patients (45 %) in the non-HBOT group underwent reoperations (p = 0.03). Of the 26 patients who did not receive HBOT after the first surgery, 15 (58 %) had one or several recurrences that lead to a new treatment: surgery (n = 11), surgery + HBO (n = 5) or just HBO (n = 1). In contrast, recurrences occurred in only 2 of 14 (14 %) who did receive HBOT after the first surgery (p < 0.01). A good outcome (Glasgow Outcome Score [GOS] of 5) was achieved in 16 patients (80 %) in the HBOT cohort versus 9 patients (45 %) in the non-HBOT group (p = 0.04).

CONCLUSIONS

HBOT was associated with less treatment failures and need for reoperation and seemingly with improved long-term outcome. Further, HBOT was well tolerated and safe. Prospective studies are warranted to establish the role of HBOT in the treatment of brain abscesses.

Management of Brain Abscess

Despite recent advances in neuroimaging techniques, brain abscesses can be difficult to diagnose and may often require surgical intervention. The primary sources of infection are often difficult to locate; hence, even if an abscess is suspected, the organisms may remain unknown. In other patients, the location of the lesion may be in a site of the brain where surgical intervention may not be possible. The types of brain abscesses, their pathophysiology including predisposing conditions, and their characteristic radiologic features are discussed in this review, with particular emphasis on the indications and modes of medical management of brain abscesses. It discusses the use of antimicrobial agents that have the best central nervous system penetration and outlines a strategy for treatment of organisms likely to infect the brain with the different types of predisposing conditions. Also discussed are the indications for empirical therapy, and antimicrobial regimens for this purpose are suggested.

Retrospective analysis of 620 cases of brain abscess in Chinese patients in a single center over a 62-year period

BACKGROUND

Despite advances in laboratory diagnostics, antibiotic regimens, and neurosurgical techniques, brain abscess (BA) remains a potentially fatal infectious disease. This study analyzed clinical and epidemiological aspects of BA in Chinese patients treated at a single center during a 62-year period.

METHOD

We retrospectively analyzed 620 BA patients treated at Tianjin Medical University General Hospital, Tianjin, PR China from 1952 to 2014. Because of the initiation of imaging technology use in 1992, and other specific changes, we analyzed data over three study periods: 1952-1972, 1980-1991, and 2002-2014. Information including incidence, sex, age, community distribution, BA size and location, therapeutic method, prognosis and outcome of BA patients was collected and evaluated.

RESULTS

Our study included 620 BA patients. The percentage mortality significantly decreased from 22.8 % in 1952 to 6.3 % in 2014 (p < 0.001). Although the incidence of BA was higher in males than females, there was no significant change in the male/female incidence ratio over time: 2.5 in 1952-1972, 2.6 in 1980-1991, and 2.2 in 2002-2014. The cryptogenic infection incidence significantly increased over time (p < 0.001). The number of positive bacterial cultures significantly decreased over the three study periods (p < 0.01).

CONCLUSIONS

The prognosis of patients with BA has gradually improved over the past 62 years in Tianjin, China. This may be because improvements in neurosurgical techniques, cranial imaging, and antimicrobial regimens have facilitated less invasive and more precise neurosurgical procedures.

Bacterial brain abscess formation in post-irradiated patients: What is the possible pathogenesis?

BACKGROUND

Until recently, post-radiotherapy brain abscess was considered rare, but it has become an increasingly important aetiology. Discussions of the relationship between bacterial brain abscess and radiotherapy (RT) are rare in the literature. Our clinical study was conducted to analyse the role of RT in the pathogenesis of bacterial brain abscess.

METHODS

For our retrospective study, 146 patients with bacterial brain abscess were recruited. Ten patients with a history of RT before brain abscess formation were reviewed.

RESULTS

Eight of these patients underwent RT treatment for nasopharyngeal carcinoma, one for olfactory neuroblastoma, and another for nasal plasmacytoma. Three showed presence of temporal lobe radiation necrosis neighbouring abscess. Eight patients were shown to have the evidence of tumour invasion. Seven had evidence of nasal infection or otitis media. Statistically significant differences between the RT and non-RT patients were observed for radionecrosis, bone defects between the middle fossa/sphenoid sinus, and the presence of nasal infection/otitis media. The mortality rate was 30%.

CONCLUSION

This study shows possible pathogenesis of bacterial brain abscess formation in post-irradiated patients, which is complicated by both radiation effects and tumour effects. Skull base deficits (either from tumour erosion or osteonecrosis) and nasal/ear infection were significantly different in patients who received radiation vs. those who did not. Radiation-related temporal lobe necrosis was also a predisposing factor. Further study based on a proper patient cohort is warranted.

Community-acquired intracranial suppurative infections: A 15-year report

Background:

The aim of this study was to retrospectively evaluate the characteristics, treatment, and prognosis of patients with intracranial suppurative infection (ISI) by review of clinical, radiological, and laboratory findings.

Methods:

The data collected from all patients who had been diagnosed with ISI and followed up at the Infectious Diseases and Clinical Microbiology Department of the study site between 1998 and 2013 were reviewed.

Results:

Of the 23 ISI patients identified, the mean age was 38.21 ± 12.61 years (range: 19–67 years, median: 34) and mean symptom duration was 22.25 ± 20.22 days. Headache was the most common symptom, the frontal lobe the most common localization of ISI, and mastoiditis due to chronic suppurative otitis media the most common source of infection causing ISI. Proteus mirabilis, Pseudomonas spp., Peptostreptococcus spp., Enterococcus avium, Mycobacterium tuberculosis complex, and Toxoplasma gondii were isolated from the specimens collected from 6 (37.5%) of the 16 patients who underwent invasive procedures. Of these 16 patients, 2 underwent craniotomy, 12 burr hole aspiration, and 2 stereotactic biopsy. The rate of recurrence was 0% and the rates of sequelae and fatality were both 8%.

Conclusions:

ISI should be considered in male patients presenting with headache and neurological signs and symptoms, whether with or without fever, on admission for early diagnosis and provision of timely, adequate therapy and, if required, surgical intervention to reduce mortality and sequelae rates.

Differentiation of pyogenic and fungal brain abscesses with susceptibility-weighted MR sequences

INTRODUCTION

Conventional magnetic resonance imaging (MRI) techniques are insufficient to determine the causative agent of brain abscesses. We investigated: (1) the value of susceptibility-weighted MR sequences (SWMRS) in the differentiation of fungal and pyogenic brain abscesses; and (2) the effect of different SWMRS (susceptibility-weighted imaging (SWI) versus venous blood oxygen level dependent (VenoBOLD)) for the detection of specific imaging characteristics of pyogenic brain abscesses.

METHODS

We studied six patients with fungal and ten patients with pyogenic brain abscesses. Imaging characteristics on conventional MRI, diffusion-weighted imaging (DWI) and SWMRS were recorded in all abscesses. All lesions were assessed for the presence of a "dual-rim sign" on SWMRS.

RESULTS

Homogenously hyperintense lesions on DWI were present in 60 % of patients with pyogenic abscesses, whereas none of the patients with fungal abscesses showed such lesions. On SWMRS, 90 % of patients with pyogenic abscesses and 60 % of patients with fungal abscesses had only lesions with a low-signal-intensity rim. On SWI, the dual-rim sign was apparent in all pyogenic abscesses. None of the fungal abscesses on SWI (P = 0.005) or any of the pyogenic abscesses on VenoBOLD (P = 0.005) were positive for a dual-rim sign.

CONCLUSIONS

In fungal abscesses, the dual-rim sign is not present but a prominent peripheral rim or central susceptibility effects on SWI will be seen. The appearance of pyogenic abscesses on SWMRS depends on the used sequence, with the dual-rim sign a specific feature of pyogenic brain abscesses on SWI.

Brain abscess due to odontogenic infection: a case report

In this report, we describe a case of brain abscess due to odontogenic infection. A 53-year-old female who had been suffering from headache and trismus for two weeks visited the Department of Oral and Maxillofacial Surgery at the Sun Dental Hospital (Daejeon, Korea). Even after several routine tests, we still could not make a diagnosis. However, after the combined multidisciplinary efforts of oral surgeons and neurosurgeons, the patient was treated for odontogenic infection and made an uneventful recovery. Therefore, patients with infections in the head and neck region showing symptoms such as headache, changes in mental state, nausea, vomiting, seizures, hemiplegia, speech disturbance, and visual disturbance, a brain abscess should be included in the list of differential diagnoses.

Brain abscess: Current management

Brain abscess (BA) is defined as a focal infection within the brain parenchyma, which starts as a localized area of cerebritis, which is subsequently converted into a collection of pus within a well-vascularized capsule. BA must be differentiated from parameningeal infections, including epidural abscess and subdural empyema. The BA is a challenge for the neurosurgeon because it is needed good clinical, pharmacological, and surgical skills for providing good clinical outcomes and prognosis to BA patients. Considered an infrequent brain infection, BA could be a devastator entity that easily left the patient into dead. The aim of this work is to review the current concepts regarding epidemiology, pathophysiology, etiology, clinical presentation, diagnosis, and management of BA.

Pyogenic brain abscess, a 15 year survey

Background

Brain abscess is a potentially fatal disease. This study assesses clinical aspects of brain abscess in a large hospital cohort.

Methods

Retrospective review of adult patients with pyogenic brain abscess at Rigshospitalet University Hospital, Denmark between 1994 and 2009. Prognostic factors associated with Glasgow Outcome Score (GOS) (death, severe disability or vegetative state) were assessed by logistic regression.

Results

102 patients were included. On admission, only 20% of patients had a triad of fever, headache and nausea, 39% had no fever, 26% had normal CRP and 49% had no leucocytosis. Median delay from symptom onset to antibiotic treatment was 7 days (range 0–97 days). Source of infection was contiguous in 36%, haematogenous in 28%, surgical or traumatic in 9% and unknown in 27% of cases. Abscess location did not accurately predict the portal of entry. 67% were treated by burr hole aspiration, 20% by craniotomy and 13% by antibiotics alone. Median duration of antibiotic treatment was 62 days. No cases of recurrent abscess were observed. At discharge 23% had GOS ≤3. The 1-, 3- and 12-month mortality was 11%, 17% and 19%. Adverse outcome was associated with a low GCS at admission, presence of comorbidities and intraventricular rupture of abscess.

Conclusions

The clinical signs of brain abscess are unspecific, many patients presented without clear signs of infection and diagnosis and treatment were often delayed. Decreased GCS, presence of comorbidities and intraventricular rupture of brain abscess were associated with poor outcome. Brain abscess remains associated with considerable morbidity and mortality.

Cerebral and subdural abscess with spatio-temporal multiplicity 12 years after initial craniotomy for acute subdural hematoma. Case report

A 34-year-old man presented with a case of subdural empyema and cerebral abscess that developed 12 years after initial neurosurgical intervention for a traffic accident in 1998. Under a diagnosis of acute subdural hematoma and cerebral contusion, several neurosurgical procedures were performed at another hospital, including hematoma removal by craniotomy, external decompression, duraplasty, and cranioplasty. The patient experienced an epileptic seizure, and was referred to our hospital in March 2010. Magnetic resonance imaging revealed a cerebral abscess extending to the subdural space just under the previous surgical field. Surgical intervention was refused and antimicrobial treatment was initiated, but proved ineffective. Surgical removal of artificial dura and cranium with subdural empyema, and resection of a cerebral abscess were performed on May 12, 2010. No organism was recovered from the surgical samples. Meropenem and vancomycin were selected as perioperative antimicrobial agents. No recurrence of infection has been observed. Postneurosurgical subdural empyema and cerebral abscess are recently emerging problems. Infections of neurosurgical sites containing implanted materials occur in 6% of cases, usually within several months of the surgery. Subdural empyema and cerebral abscess developing 12 years after neurosurgical interventions are extremely rare. The long-term clinical course suggests less pathogenic organisms as a cause of infection, and further investigations to develop appropriate antimicrobial selection and adequate duration of antimicrobial administration for these cases are needed.

Primary intracranial abscess localized in the basal ganglia: a case report

Brain abscesses are serious infections that cause neurological problems and generally require antibiotic treatment and surgical drainage. Hematogenous brain abscesses are generally located in the region fed by the middle cerebral artery, but are occasionally found in deep tissues, such as the basal ganglia and thalamus.

Metagenomic analysis of brain abscesses identifies specific bacterial associations

BACKGROUND

The bacterial flora involved in brain abscess is often complex. In a previous study, using a metagenomic approach based on 16S ribosomal DNA (rDNA) amplification, we demonstrated that the diversity of the microbial flora involved in these infections was underestimated.

METHODS

We performed a 16S rDNA-based metagenomic analysis of cerebral abscesses from patients diagnosed from 2006 through 2010. All bacteria present in brain abscess specimens were identified, in view of the clinical and epidemiological characteristics of the patients.

RESULTS

Fifty-one patients were included in our study. By detecting polymicrobial infections in 19 patients, our strategy was significantly more discriminatory and enabled the identification of a greater number of bacterial taxa than did culture and conventional 16S rDNA polymerase chain reaction (PCR) and sequencing, respectively (P < 10(-2)). Data mining discriminated 2 distinct bacterial populations in brain abscess from dental and sinusal origin. In addition, of the 80 detected bacterial species, we identified 44 bacteria that had never been found in brain abscess specimens, including 22 uncultured bacteria. These uncultured agents mostly originated from the buccal or sinusal floras (P < 10(-2)) and were found in polymicrobial specimens (P < 10(-2)).

CONCLUSIONS

Cloning and sequencing of PCR-amplified 16S rDNA is a highly valuable method to identify bacterial agents of brain abscesses.

Pyogenic ventriculitis complicating Aggregatibacter aphrophilus infective endocarditis: A case report and literature review

Pyogenic ventriculitis (PV) is an uncommon, but frequently fatal infection that results from inflammation of the ventricular ependymal lining associated with a purulent ventricular system. PV has been rarely reported as a secondary complication of infective endocarditis. Prompt diagnosis and treatment with appropriate culture-directed antibiotics with adequate central nervous system penetration is crucial when managing patients who are suspected of having PV. The present study reports on a fatal case of a previously well 42-year-old alcoholic woman with infective endocarditis caused by Aggregatibacter aphrophilus, with secondary brain abscess and spontaneous rupture into the ventricles causing PV.

"Case files from the University of Florida: When an Earache is more than an Earache": A case report

Brain abscess is not a common diagnosis as there are only approximately 2000 cases reported each year in the United States. There are three main routes of access to the brain including contiguous infection from the oropharynx, direct implantation and hematogenously. We present a case of brain abscess in a child who had multiple visits for ear pain to various physicians including pediatricians and to emergency departments. Additionally, the microbiology of brain abscesses is briefly discussed, as is treatment.

[Unilateral hydrocephalus secondary to a brain temporal abscess treated by endoscopic septotomy: a case report]

Hydrocephalus is a rare complication of brain abscess, due to either the mass effect on the ventricular system or to the rupture of the abscess in the ventricles. We report here the case of 44-year-old man who was operated on for a temporal lobe abscess of pulmonary origin who presented 6 weeks later with obstructive hydrocephalus secondary to a likely choroid plexus thrombophlebitis. This patient was treated successfully with an endoscopic septotomy. In light of the pertinent literature, we discuss the pathophysiological and management aspects of this unusual entity.

Optimization of bacterial diagnosis yield after needle aspiration in immunocompetent adults with brain abscesses

OBJECTIVE

Brain abscesses (BA) are life threatening, even in immunocompetent patients, in part because microbiological diagnosis is often lacking and management is empirical. Recent epidemiological changes make it all the more important to have a precise microbiological diagnosis. Our purpose was to evaluate the efficacy of a strategy aimed at obtaining a microbiological diagnosis in immunocompetent patients presenting with suspected BAs.

METHODS

We conducted a cohort study including all consecutive patients suspected of having BAs according to clinical, biological, and radiological findings. Severely immunocompromised patients were excluded. Aspiration was performed free-hand in patients with superficial abscesses (<1 cm depth from the cortical surface) and under stereotactic guidance in patients with deep-seated abscesses. Microbiological diagnosis was optimized, using the best aerobic and anaerobic growth conditions, blood culture bottles inoculated in the operating room, and molecular biology techniques if necessary. Antibiotic treatment was adapted according to the findings.

RESULTS

Twenty-six patients were suspected of having BAs during the study period. Twenty-four patients benefited from aspiration (stereotactic puncture in 3 cases), which was safe, confirmed the diagnosis of BAs, and yielded microbiological diagnosis in all cases, even in those patients who had previously received antibiotics (n = 8; 33%). In 10 patients (42%), microbiological results led to a different choice in antibiotic therapy than the recommended empirical regimen.

CONCLUSION

Microbiological diagnosis can be obtained in all cases of BA. This is achieved by the conjunction of rapid needle aspiration and the optimization of microbiological diagnosis resulting from fast management of the surgical specimen, good anaerobic culture conditions, and the use of blood culture bottles and molecular biology techniques when appropriate. Moreover, it is of clinical and therapeutic interest when BAs are suspected in immunocompetent patients.

[Brain abscess (80 cases)]

BACKGROUND AND PURPOSE

Cerebral abscesses are focal suppurations of infectious origin developed within the cerebral parenchyma. This is a rare pathology, with a relatively poor prognosis. Therapy continues to be debated and the results are inconsistent. The objectives of this study were to define the factors influencing prognosis.

METHODS

In a search for predictive factors, we analyzed 80 observations of intracranial abscesses compiled between January 1990 and December 2004.

RESULTS

We noted a strong male prevalence (7:1) with age ranging from three to 65 years. The duration of symptoms was short in 34 patients (42.5%). A motor deficit existed in 25 cases (31.25%), aphasia in five patients, and seizure in 11. A CT scan in 77 patients and MRI in three patients provided the diagnosis in all patients. The supratentorial location was found in 72.5% of the cases. Otitis ranked first among etiologies, followed by cranial injuries and sinusitis. The pathogenic agent found in the pus from the abscess was seldom found at the entry point. Staphylococcus aureus was found in 12.1% of the cases, followed by Proteus (11.8% of the cases). Seventy-eight patients underwent surgery, two were treated with antibiotics only, with favorable progression in 76.3%. We noted a 13.1% rate of complications and five deaths.

CONCLUSIONS

Comparing the data from this study with those of the literature, we observed that progression was better among young patients with a mean age of 20-35 years, a good level of consciousness, and supratentorial location.

Bacterial brain abscesses: prognostic value of an imaging severity index

AIM

To assess the correlation between imaging findings [computed tomography (CT) or magnetic resonance imaging (MRI)] and neurological status before and after the treatment of bacterial brain abscesses.

MATERIALS AND METHODS

CT and MRI images of 96 patients with brain abscesses were retrospectively evaluated in terms of the number, location and size of lesions, and the presence and extent of perilesional oedema and midline shift. An imaging severity index (ISI) based on these different radiological parameters was calculated. Initial Glasgow Coma Scale (GCS) scores and ISI were assessed and the prognostic value of these two indices was calculated. The Pearson correlation test, Mann-Whitney test, Chi-square test, receiver-operating characteristic (ROC) analysis, together with comparison of ROC analyses and Fisher's exact test were used.

RESULTS

There was a negative correlation between ISI and the initial GCS values: ISI increased as the GCS score decreased, indicating an inverse relationship (r=-0.51, p<0.0001). There was a significant difference between the ISI and GCS scores of patients with an adverse event compared with patients with good recovery. Outcome was significantly worse in patients with initial ISI over the calculated cut-off values of 8 points or GCS scores under the cut-off value of 13 points.

CONCLUSION

ISI is a useful prognostic indicator for bacterial brain abscess patients and correlates strongly with the patient outcome for all parameters studied. ISI score had a better prognostic value than GCS.

Pitfalls in the diagnosis of brain tumours

Establishing the diagnosis of a brain tumour is not always a straightforward process. Many non-neoplastic neurological diseases can mimic brain neoplasms on neuroimaging or on histological examination, including multiple sclerosis, stroke, pyogenic abscess, toxoplasmosis, tuberculosis, cysticercosis, fungal infections, syphilis, sarcoidosis, Behçet disease, radiation necrosis, venous thrombosis, and others. Conversely, several types of brain neoplasms, such as glioblastomas, low-grade gliomas, CNS lymphomas, and brain metastases, can present in the absence of typical tumefactive lesions, posing significant diagnostic challenges. In this Review, we discuss the process of accurately establishing the diagnosis of brain tumours, focusing on pitfalls commonly encountered in clinical practice. We also discuss the rational use and limitations of new diagnostic techniques, such as diffusion-weighted MRI, perfusion-weighted MRI, magnetic resonance spectroscopy, single-photon emission tomography, and positron emission tomography, as well as new tools for histological examination, such as immunohistochemistry and molecular genetics analysis.