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Brain abscesses (BA) are focal parenchymal infections that remain life-threatening conditions. Polymicrobial BAs (PBAs) are complex coinfections of bacteria or bacterial and nonbacterial pathogens such as fungi or parasites, with diagnostic and therapeutic challenges. In this article, we comprehensively review the prevalence, pathogenesis, clinical manifestations, and microbiological, histopathological, and radiological features of PBAs, as well as treatment and prognosis. While PBAs and monomicrobial BAs have some similarities such as nonspecific clinical presentations, PBAs are more complex in their pathogenesis, pathological, and imaging presentations. The diagnostic challenges of PBAs include nonspecific imaging features at early stages and difficulties in identification of some pathogens by routine techniques without the use of molecular analysis. Imaging of late-stage PBAs demonstrates increased heterogeneity within lesions, which corresponds to variable histopathological features depending on the dominant pathogen-induced changes in different areas. This heterogeneity is particularly marked in cases of coinfections with nonbacterial pathogens such as Toxoplasma gondii. Therapeutic challenges in the management of PBAs include initial medical therapy for possibly underrecognized coinfections prior to identification of multiple pathogens and subsequent broad-spectrum antimicrobial therapy to eradicate identified pathogens. PBAs deserve more awareness to facilitate prompt and appropriate treatment., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Association of Neuropathologists, Inc.)

Objective: To discuss the management of sigmoid sinus thrombophlebitis secondary to middle ear cholesteatoma., Methods: We retrospectively analyzed all cases of sigmoid sinus thrombophlebitis caused by middle ear cholesteatoma over a period of 7 years. 7 male and 2 female patients, ranging in age from 9 to 66 years, were diagnosed with sigmoid sinus thrombophlebitis by clinical presentation and radiological examination. By executing a modified mastoidectomy and tympanoplasty (canal wall-down tympanoplasty) to entirely remove the cholesteatoma-like mastoid epithelium, all patients were effectively treated surgically without opening the sigmoid sinus. All patients were treated with broad-spectrum antibiotics, but no anticoagulants were used., Results: 9 patients had otogenic symptoms such as ear pus, tympanic membrane perforation, and hearing loss. In the initial stage of the surgery, modified mastoidectomy and tympanoplasty were performed on 8 of the 9 patients. 1 patient with a brain abscess underwent puncturing (drainage of the abscess) to relieve cranial pressure, and 4 months later, a modified mastoidectomy and tympanoplasty were carried out. Following surgery and medication, the clinical symptoms of every patient improved. After the follow-up of 6 months to 7 years, 3 patients were re-examined for MRV and showed partial sigmoid sinus recovery with recanalization. 4 months following middle ear surgery, the extent of a patient's brain abscess lesions was significantly reduced. 1 patient experienced facial paralysis after surgery and recovered in 3 months. None of the patients had a secondary illness, an infection, or an abscess in a distant organ., Conclusion: The key to a better prognosis is an adequate course of perioperative antibiotic medication coupled with surgical treatment. A stable sigmoid sinus thrombus can remain for a long time after middle ear lesions have been removed, and it is less likely to cause infection and abscesses in the distant organs. The restoration of middle ear ventilation is facilitated by tympanoplasty. It is important to work more closely with multidisciplinary teams such as neurology and neurosurgery when deciding whether to perform lateral sinusotomies to remove thrombus or whether to administer anticoagulation., (© 2023. The Author(s).)

Rhinocladiella mackenziei is a highly neurotropic fungus, mainly reported from the Middle East. However, in recent years, there have been some cases from outside this region. We described an additional fatal case of R. mackenziei cerebral infection for the first time from Turkey and made a literature review of all previously reported cases. During 34 years (1988-2022), there have been 42 R. mackenziei brain abscess cases. Most patients have been reported from Saudi Arabia (n = 14, 33.3%). It is noteworthy that 40.5% of patients, including our case, were immunocompetent at initial diagnosis and mostly presented with a single lesion (n = 10, 23.8%). The most frequent comorbidities were solid organ transplant (n = 9, 21.4%), diabetes mellitus (n = 6, 14.3%), malignancy (n = 6, 14.3%) and prior surgery (n = 3, 7.1%). The most commonly used initial antifungal regimen were amphotericin B together with itraconazole (n = 9, 21.4%), combinations of lipid preparations of amphotericin B, voriconazole and/or posaconazole (n = 9, 21.4%) and amphotericin B alone (n = 8, 19%). Although both surgical procedures and antifungal medication in the majority of patients were performed, mortality rates remained high (90.4%). The area at risk of R. mackenziei cerebral abscess cases extends to other countries. Clinicians should be aware of this emerging disease and take a detailed travel history in patients with atypical and undocumented brain abscesses. Our case confirms the hypothesis that this fungus might spread more widely than previously predicted regions., (© 2023 The Authors. Mycoses published by Wiley-VCH GmbH.)

Diffusion-weighted imaging (DWI) and its numerical expression via apparent diffusion coefficient (ADC) values are commonly utilized in non-invasive assessment of various brain pathologies. Although numerous studies have confirmed that ADC values could be pathognomic for various ring-enhancing lesions (RELs), their true potential is yet to be exploited in full. The article was designed to introduce an image analysis method allowing REL recognition independently of either absolute ADC values or specifically defined regions of interest within the evaluated image. For this purpose, the line of interest (LOI) was marked on each ADC map to cross all of the RELs' compartments. Using a machine learning approach, we analyzed the LOI between two representatives of the RELs, namely, brain abscess and glioblastoma (GBM). The diagnostic ability of the selected parameters as predictors for the machine learning algorithms was assessed using two models, the k-NN model and the SVM model with a Gaussian kernel. With the k-NN machine learning method, 80% of the abscesses and 100% of the GBM were classified correctly at high accuracy. Similar results were obtained via the SVM method. The proposed assessment of the LOI offers a new approach for evaluating ADC maps obtained from different RELs and contributing to the standardization of the ADC map assessment., (© 2023. The Author(s).)

Background: Abscesses of the chiasmatic-sellar region are quite rare and are often a result of surgical intervention, trauma, or tumor growth. Primary abscesses are extremely rare and represent a group of abscesses the occur because of internal microbial seeding. Primary abscesses are rarely reported. We present 2 clinical cases featuring primary abscesses of the chiasmal-sellar region. To put into perspective the rarity of these findings, we performed a systematic review of existing clinical reports regarding this pathology., Methods: A systematic review of literature was conducted to gather existing clinical reports on primary abscesses of the chiasmatic-sellar region. Two personal findings are added to the literature review, including a 13-year-old girl and a 58-year-old man who presented with chiasmal-sellar region primary abscesses. The diagnostic aspects, treatment strategy, and outcomes are discussed., Results: Both patients included in the report had positive outcome. The pediatric patient developed a recurrence of the abscess and was treated accordingly. Overall, 41 cases of primary abscesses of this region have been reported in literature, of which 6 are in children under 18 years of age. The main nonspecific clinical manifestations include headaches, visual impairment, and endocrine pathology. Acute inflammatory responses are rarely seen, despite infectious genesis. Transnasal endoscopic surgical treatment offers diagnostic and treatment advantages., Conclusions: Proper diagnostic procedures can aid in correct treatment strategy and improve overall outcome., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Brain abscess can be life-threatening and manifest various neurological findings, although the mortality rate has decreased recently. We investigated the risk factors for unfavorable outcomes of patients with brain abscess., Methods: A retrospective cohort study examined patients with brain abscess seen from May 2005 to December 2018 in a tertiary care hospital in Seoul, South Korea. We reviewed the medical records for clinical findings, therapeutic modalities, and prognostic factors of brain abscess. Unfavorable clinical outcomes were defined as death, moderate to severe disability with neurological deficits, or vegetative state at 1 year or at the time of discharge from outpatient follow-up., Results: The study enrolled 135 patients: 65.2% were males; the mean age was 56 years. 35.6% had unfavorable outcomes. In multivariate analysis, higher Sequential Organ Failure Assessment (SOFA) (p < 0.001), pre-existing hemiplegia (p = 0.049), and higher Charlson comorbidity index (CCI) (p = 0.028) were independently associated with unfavorable outcomes., Conclusions: Higher SOFA, pre-existing hemiplegia and higher Charlson comorbidity index were significant risk factors for unfavorable clinical outcomes in patients with brain abscess., Competing Interests: The authors have declared that no competing interests exist.

Background: Brain abscess due to the Nocardia genus is rarely reported and it is usually found in immunocompromised patients. Treatment of Nocardia brain abscess is troublesome and requires consideration of the severity of the underlying systemic disease. The difficulties in identifying the bacterium and the frequent delay in initiating adequate therapy often influence the prognosis of patients., Case Presentation: Here, we report a rare case of brain abscess caused by Nocardia farcinica. The patient's medical history was complicated: he was hospitalized several times, but no pathogens were found. At last, bacteria were found in the culture of brain abscess puncture fluid; the colony was identified as Nocardia farcinica by mass spectrometry. Targeted antibiotic treatment was implemented, brain abscess tended to alleviate, but the patient eventually developed fungal pneumonia and died of acute respiratory distress syndrome (ARDS)., Conclusion: Brain abscess caused by Nocardia farcinica can appear in non-immunocompromised individuals. Early diagnosis, reasonable surgical intervention, and targeted antibiotic treatment are critical for Nocardia brain abscess treatment. In the treatment of Nocardia brain abscess, attention should paid be to the changes in patients' immunity and infection with other pathogens, especially fungi, avoided., (© 2021. The Author(s).)

Granulomatous amebic encephalitis (GAE) caused by Acanthamoeba is a rare infection with central nervous system (CNS) involvement usually with fatal consequences. Currently, information regarding GAE in children is scarce and is limited only to case reports and case series. A 13-year-old immunocompetent male patient with a 6-month history of progressive and intermittent headaches presented to our institution. One week before hospital admission, the patient showed signs of CNS involvement. Magnetic resonance imaging revealed multiple lesions with supra- and infratentorial cerebral abscesses. An empiric treatment with combined antibiotics was given, but the patient died after 20 days of hospital stay. A postmortem diagnosis confirmed GAE. Although it is a rare disease in pediatric patients, GAE should be considered in children with a chronic history of fever, headache, and vomiting with CNS involvement.

Background: There are limit studies about pediatric brain abscess in China. The aim of this study was to analyze clinical characteristics and outcomes of pediatric brain abscess in recent years in China., Methods: The clinical information of children with brain abscess hospitalized in Beijing Children's Hospital between January 1, 2007 and December 31, 2016 were retrospectively reviewed., Results: Ninety-four children were enrolled in this study. A Streptococcus milleri group (13.8%) was identified as the most common causative organisms, followed by Staphylococcus aureus (6.4%). The overall mortality was 21.6%, with 50.0% of deaths happening in the first week after diagnosis. Long-term outcomes of 74 patients were assessed with Glasgow Outcome Scale-Extended Pediatric Reversion: 50 patients with a score of 1-2 (favorable outcome) and 24 patients with a score of 3-8 (unfavorable outcome). Patients with multiple abscesses (P = 0.029) and intraventricular rupture of brain abscess/hydrocephalus (P = 0.024) had higher risk of unfavorable outcomes., Conclusions: Brain abscess is a serious disease with high mortality in children; more aggressive treatments should be considered in the first week of diagnosis because of high risk of death, and for patients with multiple brain abscesses and intraventricular rupture of brain abscess/hydrocephalus because of their higher risk of unfavorable., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Bacterial brain abscesses are typically spread through a haematogenous route. Open head wounds and neurosurgical interventions are uncommon aetiologies. Ectopic tissue found in the cerebral cortex is usually ascribed almost entirely from carcinomas. Here, we describe a 57-year-old gentleman who, 22 years after a fireworks related traumatic injury to the left orbit, presented with headaches and altered behaviour. Imaging revealed an abscess immediately superior to the orbit, whose bacterial aetiology was identified to be Pseudomonas aeruginosa, encapsulated by ciliated respiratory epithelium. This represents a case in which tissue was displaced during the initial trauma or craniofacial reconstructive surgery from the frontal sinus., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Phaeohyphomycosis causes a wide spectrum of systemic manifestations and can affect even the immunocompetent hosts. Involvement of the central nervous system is rare. A 48-year-old farmer presented with chronic headache, fever, and impaired vision and hearing. Serial MRIs of the brain showed enhancing exudates in the basal cisterns, and lesions in the sella and perichiasmatic and cerebellopontine angle regions along with enhancement of the cranial nerves and leptomeninges. Cerebrospinal fluid (CSF) showed lymphocytic pleocytosis with elevated protein and decreased glucose on multiple occasions. Clinical, imaging, and CSF abnormalities persisted despite treatment with antitubercular drugs and steroids for 2 years. Biopsy of the dura mater at the cervicomedullary junction revealed necrotizing granulomatous lesions, neutrophilic abscesses, and giant cells containing slender, pauci-septate, pigmented fungal hyphae. Fungal culture showed growth of Fonsecaea pedrosoi , which is classically known to cause brain abscesses. Here, we report the diagnostic odyssey in a patient with chronic meningitis from a region endemic for tuberculosis and describe the challenges in establishing the accurate diagnosis. Lack of therapeutic response to an adequate trial of empirical antitubercular therapy warrants search for alternative causes, including fungal meningitis. We highlight the uncommon manifestation of F. pedrosoi with chronic meningitis as well as the protracted clinical course despite not receiving antifungal therapy.

The control of inflammation and infection is crucial for periodontal wound healing and regeneration. M101, an oxygen carrier derived from Arenicola marina, was tested for its anti-inflammatory and anti-infectious potential based on its anti-oxidative and tissue oxygenation properties. In vitro, no cytotoxicity was observed in oral epithelial cells (EC) treated with M101. M101 (1 g/L) reduced significantly the gene expression of pro-inflammatory markers such as TNF-α, NF-κΒ and RANKL in P. gingivalis-LPS stimulated and P. gingivalis-infected EC. The proteome array revealed significant down-regulation of pro-inflammatory cytokines (IL-1β and IL-8) and chemokine ligands (RANTES and IP-10), and upregulation of pro-healing mediators (PDGF-BB, TGF-β1, IL-10, IL-2, IL-4, IL-11 and IL-15) and, extracellular and immune modulators (TIMP-2, M-CSF and ICAM-1). M101 significantly increased the gene expression of Resolvin-E1 receptor. Furthermore, M101 treatment reduced P. gingivalis biofilm growth over glass surface, observed with live/dead analysis and by decreased P. gingivalis 16 s rRNA expression (51.7%) (p < 0.05). In mice, M101 reduced the clinical abscess size (50.2%) in P. gingivalis-induced calvarial lesion concomitant with a decreased inflammatory score evaluated through histomorphometric analysis, thus, improving soft tissue and bone healing response. Therefore, M101 may be a novel therapeutic agent that could be beneficial in the management of P. gingivalis associated diseases.

Background: Pituitary abscesses within pre-existing pituitary conditions, such as craniopharyngioma, pituitary adenoma, or Rathke cleft cyst, are quite rare. A case of pituitary abscess secondary to adenoma is presented, and the literature is reviewed., Case Description: An 11-year-old boy presented with a 3-day history of sudden-onset headache and visual loss. Magnetic resonance imaging demonstrated a sellar region lesion with intralesional hemorrhage. Preoperative diagnosis was pituitary adenoma with apoplexy. An endoscopic transnasal transsphenoidal approach was used for emergent total tumor resection. Pathology confirmed the diagnosis of pituitary adenoma with apoplexy and inflammation, and microbiologic examination was positive for Staphylococcus aureus., Conclusions: Secondary pituitary abscess is a rare entity, and preoperative diagnosis is challenging. The treatment strategy includes prompt surgical resection and drainage of the abscess, followed by prolonged antibiotic therapy., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Brain abscesses represent areas of localised infection of the brain parenchyma. Those confined to the brainstem are rare and usually fatal if untreated. Streptococcus intermedius is a common causative organism of brain abscesses and is associated with significant morbidity. We describe a case report of medullary abscess secondary to dental infection in a 68-year-old patient. The patient presented with headaches and flu-like symptoms progressing to left hemiparesis and reduced consciousness/bulbar function. The patient underwent emergency posterior fossa craniectomy and drainage with subsequent medical management with antibiotics. Prompt diagnosis, early surgical intervention and maximal therapy with antibiotics alongside extensive rehabilitation are all vital to ensure good neurological outcome. It is imperative for medical practitioners to consider the diagnosis of brain abscess in patients presenting with rapid onset neurological deterioration. Such cases require early neurological imaging with involvement of tertiary neurosurgery services., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Design (DF) and phonemic fluency tests (FAS; D-KEFS, 2001) are commonly used to investigate voluntary generation. Despite this, several important issues remain poorly investigated. In a sizeable sample of patients with focal left or right frontal lesion we established that voluntary generation performance cannot be accounted for by fluid intelligence. For DF we found patients performed significantly worse than healthy controls (HC) only on the switch condition. However, no significant difference between left and right frontal patients was found. In contrast, left frontal patients were significantly impaired when compared with HC and right frontal patients on FAS. These lateralization findings were complemented, for the first time, by three neuroimaging; investigations. A traditional frontal subgrouping method found significant differences on FAS between patients with or without Left Inferior Frontal Gyrus lesions involving BA 44 and/or 45. Parcel Based Lesion Symptom Mapping (PLSM) found lower scores on FAS were significantly associated with damage to posterior Left Middle Frontal Gyrus. An increase in rule break errors, so far only anecdotally reported, was associated with damage to the left dorsal anterior cingulate and left body of the corpus callosum, supporting the idea that conflict resolution and monitoring impairments may play a role. Tractwise statistical analysis (TSA) revealed that patients with disconnection; in the left anterior thalamic projections, frontal aslant tract, frontal; orbitopolar tract, pons, superior longitudinal fasciculus I and II performed significantly worse than patients without disconnection in these tracts on FAS. In contrast, PLSM and TSA analyses did not reveal any significant relationship between lesion location and performance on the DF switch condition. Overall, these findings suggest DF may have limited utility as a tool in detecting lateralized frontal executive dysfunction, whereas FAS and rule break behavior appears to be linked to a set of well localized left frontal grey matter regions and white matter tracts., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: Intraventricular rupture of brain abscess (IVROBA) is one of the most dreaded complications of pyogenic brain abscess due to its high mortality rate. Because of its relative infrequency and poor outcome, the optimal management of this condition remains to be determined., Patients and Methods: We report the case of a 5-year old female with a presumptive diagnosis of IVROBA who was discharged with good neurologic outcome after completing intravenous antibiotic treatment and undergoing insertion of an external ventricular drain (EVD) and later, a ventriculoperitoneal (VP) shunt. We also performed a systematic review of the SCOPUS and PubMed databases for case reports and series documenting patients who survived after undergoing treatment for IVROBA., Results: A total of 24 cases of IVROBA survivors were reported in the literature, including the present case. The median age was 48.5 years (range: 5-71), with a male predilection (3:1). The most common location of the brain abscesses was temporal while the most common route of spread was hematogenous. Surgery was performed in 92% of cases, with EVD being the most common surgical procedure. Twenty nine percent of cases required a VP shunt. The duration of systemic antibiotic treatment ranged from 31 to 180 days (median: 56 days) while intraventricular antibiotics were given for 8-42 days (median: 14 days)., Conclusion: The management of IVROBA in this series varied widely, with surgery playing an important role. Although IVROBA is still a devastating complication of intracranial abscess, a good neurologic outcome may still be possible with treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Competing Interests: None

This study aims to identify predictive factors related to clinical outcome, reoperation, and complications in patients with brain abscess.Patients with a diagnosis of brain abscess at discharge at the Second Affiliated Hospital of Zhejiang University School of Medicine between 2008 and 2018 were reviewed. Logistic regression was used to identify predictive factors associated with Glasgow Outcome Scale (GOS) at discharge, GOS at 1 year after discharge, reoperation and complications.Among 183 patients enrolled into the study, 142 patients had a good outcome at discharge (GOS ≥ 4) and 41 had a poor outcome (GOS ≤ 3). During the follow-up period, 20 additional patients had a good outcome. A total of 156 patients were treated by open craniotomy excision (n = 72) and aspiration (n = 84), 10 of whom underwent reoperation. Complications in surgical patients for brain abscess occurred in 54 patients. Poor outcome was related to Glasgow coma scale (P = .007) and ventricular proximity (P = .001). Surgical method was associated with reoperation (P = .04) and complications (P < .001). Seizure at admission was related to epilepsy (P < .001). Surgical method was related to postoperative intracranial hemorrhage (P = .02).Glasgow coma scale (GCS) and ventricular proximity were associated with poor outcome. Further, patients who underwent aspiration were more likely to experience reoperation, while open craniotomy excision (OCE) was related to complications. Patients presenting seizure at admission were more likely to develop epilepsy. Patients who underwent OCE tended to experience postoperative intracranial hemorrhage.

Background: Several intracranial pathologies present as a ring-enhancing lesion on conventional magnetic resonance imaging (MRI), creating diagnostic difficulty. We studied the characteristics of the anatomical border of gadolinium enhancement on T1-weighted imaging (WI) and hypointensity on T2WI to employ a simple technique of histogram-profile analysis of MRI for differentiation of various ring-enhancing intracranial lesions., Methods: After approval from the institutional review board, preoperative MRI (T2WI, postcontrast T1WI) scans were analyzed retrospectively in 18 patients with histologically confirmed brain abscess, 66 glioblastomas, 46 brain-metastases, and 16 tumefactive multiple sclerosis (MS). T2WI and postcontrast T1WI were overlapped, and histogram-profile analysis was performed with in-house image-fusion software. The pattern of differential-peaks in histogram-profile was assessed visually. Kaplan-Meier survival analysis incorporating histogram-profile patterns was performed in patients with glioblastoma., Results: The histogram-profile study revealed 4 distinct patterns. Pattern 1 showed no differential T2-hypointensity trough, pattern 2 had T2-hypointensity trough inside, whereas pattern 3 had T2-hypointensity trough overlapping the enhanced margin. Pattern 4 had T2-hypointensity trough immediately external to the enhanced margin. Pattern 1 was specific for tumefactive MS (93.3%), whereas pattern 4 was specific for glioblastoma (40.7%). Pattern 4 glioblastoma was subdivided into rim (T2-hypointensity ≥50% of circumference of contrast-enhanced tumor) and arc (T2-hypointensity <50% of circumference of contrast-enhanced tumor). Pattern 4 glioblastoma was further subdivided into group A (edema: T2-hyperintensity ≥50% of circumference of contrast-enhanced tumor) and group B (less edema: T2-hyperintensity <50% of circumference of contrast-enhanced tumor). Patients with pattern 3 glioblastoma (37.6%) had better survival compared with others (P = 0.0341) and pattern 4B had decreased survival compared with pattern 4A (P = 0.0001) and others (P = 0.0003)., Conclusions: Tumefactive MS and a subset of glioblastomas show specific patterns in histogram-profile analysis. The difference in anatomical border also determines difference in survival in glioblastoma. Histogram-profile analysis is a simple and efficient technique to differentiate these pathologies., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Pituitary abscess is a rare condition, with approximately 300 cases reported in the literature. Primary pituitary abscess, the most common type, occurs in previously healthy normal glands. Secondary pituitary abscess is secondary to pre-existing lesions in the pituitary region, such as pituitary adenoma, Rathke's cleft cysts, or craniopharyngioma and infections., Material and Methods: A total of 2281 patients underwent pituitary surgery via endoscopic transsphenoidal approach in Kocaeli University Pituitary Gland Research Center between 1997 and 2018. Among this cohort 9 patients (4 female and 5 male) were diagnosed with primary pituitary abscess based on both intraoperative findings and postoperative histopathological evidence., Results: Primary pituitary abscess incidence was obtained 0.39% in our center. Mean age of the patients was 50 years old. There was no history of pituitary surgery, radiotherapy and infection diseases in our patients. Visual symptoms were prominent in two patients, hypopituitarism was found in 5 out of the 9 patients. All patients have typical pituitary lesion on pituitary magnetic resonance imaging. Staphylococcus species were the most commonly isolated organisms in the culture. A few weeks of antibiotic therapy were administered after surgery., Conclusion: Presentation of fever, headache, diabetes insipidus, hypopituitarism and a sellar cystic mass with an enhanced rim after gadolinium contrast on pituitary magnetic resonance imaging may be suggestive of a pituitary abscess. Transsphenoidal endoscopic surgery, proper antibiotics and appropriate hormone replacement therapy when necessary are the keys of pituitary abscess treatment.

Brain abscess accounts for 8% of all intracranial insults in developing countries. Anaerobic infections are missed in most cases due to difficult isolation techniques. This study was done to determine the anaerobic bacteriological profile of brain abscess, their distribution according to sociodemographic variables, anatomical location, management and the outcome during the subjects' stay in a neurosciences' speciality hospital. We included 190 cases of confirmed anaerobic brain abscess from the year 1998-2017. The median age was 22 years with more males (73% of 190 cases) than females. The Bacteroides spp. were the most common (64%) anaerobic organisms isolated followed by Gram positive anaerobic cocci (51%). While 67% of the samples showed purely anaerobic bacteria on culture, remaining were mixed. Chronic suppurative otitis media (CSOM) was the most common predisposing factor., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Robotic technologies have been used in the neurosurgical operating rooms for the last 30 yr. They have been adopted for several stereotactic applications and, particularly, image-guided biopsy of intracranial lesions which are not amenable for open surgical resection., Objective: To assess feasibility, safety, accuracy, and diagnostic yield of robot-assisted frameless stereotactic brain biopsy with a recently introduced miniaturized device (iSYS1; Interventional Systems Medizintechnik GmbH, Kitzbühel, Austria), fixed to the Mayfield headholder by a jointed arm., Methods: Clinical and surgical data of all patients undergoing frameless stereotactic biopsies using the iSYS1 robotized system from October 2016 to December 2017 have been prospectively collected and analyzed. Facial surface registration has been adopted for optical neuronavigation., Results: Thirty-nine patients were included in the study. Neither mortality nor morbidity related to the surgical procedure performed with the robot was recorded. Diagnostic tissue samples were obtained in 38 out of 39 procedures (diagnostic yield per procedure was 97.4%). All patients received a definitive histological diagnosis. Mean target error was 1.06 mm (median 1 mm, range 0.1-4 mm)., Conclusion: The frameless robotic iSYS1-assisted biopsy technique was determined to be feasible, safe, and accurate procedure; moreover, the diagnostic yield was high. The surface matching registration method with computed tomography as the reference image set did not negatively affect the accuracy of the procedure., (Copyright © 2019 by the Congress of Neurological Surgeons.)

Purpose: The purpose of this retrospective study was to investigate the differentiation of abscess and necrotic tumors, using susceptibility-weighted imaging (SWI) and apparent diffusion coefficients (ADC) either separated or combined., Methods: Imaging was performed on 26 patients with pyogenic brain abscesses, 31 patients with rim-enhancing glioblastomas, and 21 patients with rim-enhancing metastases. The degree of intralesional susceptibility signal (ILSS) was independently assessed by three observers. Average ADC in the lesion core was calculated. After receiver operating characteristic (ROC) analysis, the area under the ROC curve was compared using three different analytical models (ILSS, ADC, and ILSS-ADC combined) to differentiate abscess from the two rim-enhancing necrotic tumors., Results: The ILSS-ADC combined model had greater area under the ROC curves than ILSS or ADC used alone. In this study, the ILSS-ADC combined model showed 100% diagnostic accuracy differentiating abscesses from glioblastoma. The ADC model and the ILSS-ADC combined model performed equally well in distinguishing abscesses from metastases., Conclusion: It is concluded that SWI and ADC are complementary, and the combination of SWI and ADC may improve results compared with the use of only one model. Validation by an independent cohort is the next necessary step to broaden its applicability in routine clinical settings., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Intraventricular abscess is a rare pathology. We present a case of primary intraventricular abscess in an immunocompetent 22 year old male. We review the literature and discuss our management of this case with aspiration via neuroendoscopy., (Copyright © 2019. Published by Elsevier Ltd.)

Background: Intracranial abscess formation is an extremely rare and sporadically documented disease in South American Camelids (SACs). Herein we report the first case of otogenic brain abscess formation in this species., Case Presentation: A 4 years old female alpaca was presented to our veterinary hospital with a 6 month history of neurologic disorder symptoms, mainly head tilt to the right and emaciation. A comprehensive workup (ultrasound and computed tomography) revealed irreversible cranial nerve abnormalities, extensive lesions in the region of external, middle and internal right ear including destruction of bony structures (tympanic bulla, parts of temporal bone) and severe brain deformation caused by an intracranial abscess. The lesion was up to 6x7x4 cm and occupying almost 40% of the cranial cavity. No pathological findings were evident in other organs or structures. The late referral of the alpaca at this advanced stage of destructive disease precluded surgical intervention., Conclusions: This case report describes the clinical signs, diagnostic procedures and pathological findings in an adult female alpaca suffering from cranial nerve abnormalities caused by a massive otogenic brain abscess. Camelids suffering from otitis may not present with clinical signs until the pathology is severe. The importance of considering intracranial abscess formation as differential diagnosis in SACs showing the merest hint of nerve deficits cannot be emphasized enough in order to diagnose such pathological processes at an early and treatable stage.

Primary pituitary tubercular abscess is a very rare disease. It may present clinically with visual loss, headache, seizure, hormonal abnormalities or with cranial nerve palsies. MRI is the diagnostic modality and shows a cystic-solid mass in the sellar and suprasellar region, isointense on T1 and T2W images with heterogeneous areas and ring enhancement on contrast. Surgery remains the initial treatment and it is approached through the trans-sphenoidal/trans-nasal or transcranial route followed by anti-tubercular therapy. We report a case of primary pituitary tubercular abscess managed successfully with a brief review of its pathology. Keywords: abscess; pituitary gland; pyogenic; sella; tuberculosis.

Methanogens are strictly anaerobic archaea metabolising by-products of bacterial fermentation into methane by using three known metabolic pathways, i.e. the reduction of carbon dioxide, the fermentation of acetate or the dismutation of methanol or methylamines. Methanogens described in human microbiota include only Euryarchaeota, i.e. Methanobrevibacter smithii, Methanobrevibacter oralis, Methanobrevibacter arbophilus, Methanobrevibacter massiliensis, Methanomassiliicoccus luminyensis, Methanosphaera stadtmanae and Ca. Methanomethylophilus alvus and Ca. Methanomassiliicoccus intestinalis. Methanogens are emerging pathogens associated with brain and muscular abscesses. They have been implicated in dysbiosis of the oral microbiota, periodontitis and peri-implantitis. They have also been associated with dysbiosis of the digestive tract microbiota linked to metabolic disorders (anorexia, malnutrition and obesity) and with lesions of the digestive tract (colon cancer). Their detection in anaerobic pus specimens and oral and digestive tract specimens relies on microscopic examination by fluorescence in situ hybridisation, specific DNA extraction followed by polymerase chain reaction (PCR)-based amplification of the 16S rRNA and mcrA gene fragments and isolation and culture in the supporting presence of hydrogen-producing bacteria. Diagnostic identification can be performed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and can be further completed by genotyping through multi-spacer sequencing and, ultimately, whole genome sequencing (WGS). Ornidazole derivatives, fusidic acid and rifampicin are the compounds to be included in in vitro susceptibility testing to complete the clinical workflow. Clinical microbiology laboratories should work toward developing cheap and easy protocols for the routine detection and identification of methanogens in selected specimens in order to refine the diagnosis of infections, as well as to expand the knowledge about this group of intriguing microorganisms.

Objective: Ischaemic brain lesions and brain abscesses are frequent in both human and animal cases of septic embolic stroke. However, existing models of brain infection do not reflect central aspects of septic embolic stroke. Our aim was to compare septic and non-septic embolic stroke in order to identify gene expressions, inflammatory mediators and brain damage in a rat model., Methods: We created precisely located focal brain infarcts in a rat model of Staphylococcus aureus infected embolic stroke. To cause septic embolic stroke we used a fibrin-rich embolus with bacteria, while every rat in the control group received a non-infected embolus. 64 rats were randomized to receive sham-surgery, sterile embolic stroke or septic embolic stroke. All groups were compared for brain pathology, mortality, gene expressions and inflammatory mediators using histology and reverse transcription quantitative real-time PCR., Results: Although infarct volumes did not differ, septic embolic stroke caused higher mortality than sterile embolic stroke (p=  0.002). Brain abscesses were observed only in the septic group. Approximately 400-500 fold increases were observed for Orm1 and Cxcl2 respectively (1.00E-08 < p < 1.92E-07) in the septic group compared to the sterile group, and these were the most dramatically regulated genes in septic embolic stroke compared to sterile embolic stroke., Conclusions: Septic embolic stroke caused brain abscesses, increased mortality and upregulated Orm1 and Cxcl2 gene expressions compared to non-infected embolic stroke. The dramatic Orm1 increase observed in the septic group is unprecedented and suggests a significant biological role of Orm1 during septic neuroinflammation.

Cerebral involvement especially brain abscess is life-threatening complication and major cause of death during Scedosporium apiospermum infection. However, little is known about pathogenesis of brain oedema associated with abscess in scedosporiosis. Experimental scedosporiosis was conducted in BALB/cMlac mice to characterize the presence of brain oedema, its type, and its related mechanisms focusing on aquaporin (AQP)-4, nuclear factor erythroid-2 related factor (Nrf-2), and tumor necrotic factor (TNF)- α . The results revealed that S. apiospermum infection induced severe inflammatory environment relevant to TNF- α expression and cytogenic oedema-associated brain abscess predominately in cerebrum of immunocompromised mice without voriconazole treatment reflecting to downregulation of AQP-4 in neighboring abscess areas and oedematous blood vessels. Downregulation of Nrf-2 in neuronal cells and myelin degeneration were significantly observed in nontreated mice. In summary, oxidative stress, severe inflammatory response, and space-occupying mass from abscess formation inducing tissue hypoxia might be the postulate causes of oedema induced by scedosporiosis.

The incidence of brain abscess is higher among immunosuppressed patients. We report a case of a brain abscess in the temporal lobe in a patient under treatment with adalimumab and methotrexate, who developed radiological worsening. Clinical remission was essential to suspect Immune Reconstitution Inflammatory Syndrome and to continue empirical antimicrobial therapy due to the low suspicion of worsening of the abscess itself., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Competing Interests: Competing interests: None declared.

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.

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.

OBJECTIVE What determines the extent of tissue destruction during brain abscess formation is not known. Pyogenic brain infections cause destruction of brain tissue that greatly exceeds the area occupied by microbes, as seen in experimental studies, pointing to cytotoxic factors other than microbes in pus. This study examined whether brain abscess pus contains cytotoxic proteins that might explain the extent of tissue destruction. METHODS Pus proteins from 20 human brain abscesses and, for comparison, 7 subdural empyemas were analyzed by proteomics mass spectrometry. Tissue destruction was determined from brain abscess volumes as measured by MRI. RESULTS Brain abscess volume correlated with extracellular pus levels of antibacterial proteins from neutrophils and macrophages: myeloperoxidase (r = 0.64), azurocidin (r = 0.61), lactotransferrin (r = 0.57), and cathelicidin (r = 0.52) (p values 0.002-0.018), suggesting an association between leukocytic activity and tissue damage. In contrast, perfringolysin O, a cytotoxic protein from Streptococcus intermedius that was detected in 16 patients, did not correlate with abscess volume (r = 0.12, p = 0.66). The median number of proteins identified in each pus sample was 870 (range 643-1094). Antibiotic or steroid treatment prior to pus evacuation did not reduce the number or levels of pus proteins. Some of the identified proteins have well-known neurotoxic effects, e.g., eosinophil cationic protein and nonsecretory ribonuclease (also known as eosinophil-derived neurotoxin). The cellular response to brain infection was highly complex, as reflected by the presence of proteins that were specific for neutrophils, eosinophils, macrophages, platelets, fibroblasts, or mast cells in addition to plasma and erythrocytic proteins. Other proteins (neurofilaments, myelin basic protein, and glial fibrillary acidic protein) were specific for brain cells and reflected damage to neurons, oligodendrocytes, and astrocytes, respectively. Pus from subdural empyemas had significantly higher levels of plasma proteins and lower levels of leukocytic proteins than pus from intracerebral abscesses, suggesting greater turnover of the extracellular fluid of empyemas and washout of pus constituents. CONCLUSIONS Brain abscess pus contains leukocytic proteins that are neurotoxic and likely participate actively in the excessive tissue destruction inherent in brain abscess formation. These findings underscore the importance of rapid evacuation of brain abscess pus.

Introduction: Actinomycosis is an uncommon chronic suppurative infection that rarely affects the central nervous system (CNS). It is caused by filamentous Gram-positive anaerobic bacteria that is a normal commensal but causes suppurative and granulomatous inflammation after disruption of anatomical barriers. We report the largest series of 17 histologically confirmed cases of CNS actinomycosis and review clinical, imaging, and histopathologic features., Methods: All histologically confirmed cases of CNS actinomycosis diagnosed between January 2010 and June 2016 were retrieved from the neuropathology records. The demographic profile, clinical, radiologic, microbiologic, and histologic features, treatment, and clinical outcomes were reviewed., Results: Seventeen cases were histopathologically diagnosed to have CNS actinomycosis. Nine of these were primarily admitted and managed in our institute, whereas the remaining 8 were referred to us for histopathologic diagnosis. Mean age at presentation was 31.4 years, with male predilection (3.25:1). Mean duration of symptoms was 2.95 months. Systemic symptoms were noted in 5 patients, although no systemic focus was detectable. Pachymeningitis was most common type (9; 52.94%), and chronic abscess was identified in 7. History of previous surgery for osteomyelitis was forthcoming in 3. All patients underwent surgical excision/aspiration of the lesions. Histologically, lesions revealed characteristic suppurative granulomatous response with giant cells and actinomycotic colonies were detected within necrotic centers. Cultures failed to grow Actinomyces in all. Follow-up data were available in 9 patients managed in our institute, and all had good outcomes at the median follow-up period of 32 months after antibiotic treatment for mean period of 8.4weeks., Conclusions: Histopathology remains the cornerstone for diagnosis of actinomycosis as on culture confirmation is very rare., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Paraclostridium bifermentans (current nomenclature of Clostridium bifermentans since 2016) is a gram-positive, spore-forming anaerobic bacterium. Here, we describe two cases associated with this organism. The first, primarily a case of tubercular brain abscess where P. bifermentans was isolated as part of a polymicrobial flora, following a neurosurgical procedure for the same and the second, a case of cervical lymphadenitis from which it was isolated as the sole causative agent. There are only a few reported cases of P. bifermentans in literature and these cases illustrate the widening spectrum of infections related to it., (Copyright © 2018 Elsevier Ltd. All rights reserved.)