Brain abscess

Ten-year statewide cross-sectional review of pediatric sinogenic intracranial abscess and empyema in Queensland, Australia: microbial profile before and after COVID-19

OBJECTIVE

Sinogenic intracranial infections in children, such as subdural empyema or intracranial abscess, are a rare disease process with significant associated morbidity. Recent literature has suggested that there may have been an increase in frequency of these infections following the COVID-19 pandemic, but the literature has been conflicting, perhaps related to the heterogenous management of COVID-19 lockdowns in various states and differences in data capture between methods. The collection of statewide Australian data overcomes these limitations by capturing a comprehensive sample though the public healthcare system of patients who were subject to a homogeneous statewide approach to public health policy during the COVID-19 pandemic (population 5.6 million, including 1.3 million children). The objective of this study was to present population-level data to address the question of whether the incidence of intracranial infections changed in pediatric patients before and after the COVID-19 pandemic.

METHODS

The authors present a retrospective 10-year statewide description of sinogenic intracranial infections in Queensland, Australia. A comparison was made between the incidence and microbiological profile before and after the onset of COVID-19 lockdowns on March 22, 2020.

RESULTS

Forty-four pediatric intracranial infections undergoing neurosurgical intervention were identified within the review period. After exclusion of postsurgical and cardioembolic causes, 33 sinogenic intracranial infections were included (16 before and 17 after 2020, with a mean annualized incidence of 0.25 vs 0.37 cases per 100,000 children, respectively; p > 0.05). The most frequent organisms identified were Streptococcus milleri (n = 19), polymicrobial (n = 4), and S. aureus (n = 3). No significant differences in antimicrobial profile, susceptibility, parenchymal involvement, or clinical outcome were identified between the pre- and post-COVID-19 groups.

CONCLUSIONS

No statistically significant differences in the epidemiology of pediatric intracranial infection have occurred in the state of Queensland, Australia, before and after March 22, 2020, and the COVID-19 pandemic.

Brain Abscess in the Current Decade (2010–2019) in India—A Review

Brain abscess outcomes have improved in recent years due to advancements in cranial imaging, microbiological techniques, minimally invasive neurosurgical procedures, and effective antibiotic treatments. However, the incidence of brain abscess remains unchanged in developing countries. We searched PubMed and Google Scholar for references using the key words “brain abscess” and “India” and reviewed both retrospective and prospective studies published in peer-reviewed journals in the current decade to understand the present status. The review shows that the patients’ ages, the predominance of male patients, the symptoms and locations of brain abscesses, and the types of bacteria associated with them have remained unchanged over the past decade. The most common predisposing condition in recent years has been chronic suppurative otitis media with a mortality rate of 7 to 10%. Middle ear infection is often neglected and not treated aggressively in Asian countries. It requires multidisciplinary treatment strategies to address the primary source of infection and better health awareness to prevent the development of brain abscess.

Treating Porcine Abscesses with Histotripsy: A Pilot Study

Infected abscesses are walled-off collections of pus and bacteria. They are a common sequela of complications in the setting of surgery, trauma, systemic infections and other disease states. Current treatment is typically limited to antibiotics with long-term catheter drainage, or surgical washout when inaccessible to percutaneous drainage or unresponsive to initial care efforts. Antibiotic resistance is also a growing concern. Although bacteria can develop drug resistance, they remain susceptible to thermal and mechanical damage. In particular, short pulses of focused ultrasound (i.e., histotripsy) generate mechanical damage through localized cavitation, representing a potential new paradigm for treating abscesses non-invasively, without the need for long-term catheterization and antibiotics. In this pilot study, boiling and cavitation histotripsy treatments were applied to subcutaneous and intramuscular abscesses developed in a novel porcine model. Ultrasound imaging was used to evaluate abscess maturity for treatment monitoring and assessment of post-treatment outcomes. Disinfection was quantified by counting bacteria colonies from samples aspirated before and after treatment. Histopathological evaluation of the abscesses was performed to identify changes resulting from histotripsy treatment and potential collateral damage. Cavitation histotripsy was more successful in reducing the bacterial load while having a smaller treatment volume compared with boiling histotripsy. The results of this pilot study suggest focused ultrasound may lead to a technology for in situ treatment of acoustically accessible abscesses.

Brain abscess in immunocompetent adult patients

Brain abscess is a focal infection of the brain due to contiguous spread of pathogens following otitis, sinusitis, neurosurgery or traumatic brain injury or through hematogenous dissemination. Classical symptoms consisting of headache, fever, and focal signs may be absent on admission and brain MRI with contrast plays a major role in diagnosis. Initial management consists of stereotactic aspiration for microbiological documentation empirical treatment covering common pathogens, including oral streptococci, staphylococci, anaerobes, and Enterobacteriaceae. De-escalation of antimicrobials based on microbiology is safe only when samples have been processed optimally, or when primary diagnosis is endocarditis. A 6-week combination of third-generation cephalosporin and metronidazole will cure most cases of community-acquired brain abscess in immunocompetent adults. Significant advent in brain imaging, minimally invasive surgery, molecular biology, and antibacterial agents, has dramatically improved the prognosis. Main indicators of outcome include altered mental status at presentation and intraventricular rupture.

An update on bacterial brain abscess in immunocompetent patients

BACKGROUND

A brain abscess is a focal infection of the brain that begins as a localized area of cerebritis. In immunocompetent patients, bacteria are responsible for >95% of brain abscesses, and enter the brain either through contiguous spread following otitis, sinusitis, neurosurgery, or cranial trauma, or through haematogenous dissemination.

AIMS

To identify recent advances in the field.

SOURCES

We searched Medline and Embase for articles published during years 2012-2016, with the keywords 'brain' and 'abscess'.

CONTENT

The triad of headache, fever and focal neurological deficit is complete in ∼20% of patients on admission. Brain imaging with contrast-preferentially magnetic resonance imaging-is the reference standard for diagnosis, and should be followed by stereotactic aspiration of at least one lesion, before the start of any antimicrobials. Efforts should be made for optimal management of brain abscess samples, for reliable microbiological documentation. Empirical treatment should cover oral streptococci (including milleri group), methicillin-susceptible staphylococci, anaerobes and Enterobacteriaceae. As brain abscesses are frequently polymicrobial, de-escalation based on microbiological results is safe only when aspiration samples have been processed optimally, or when primary diagnosis is endocarditis. Otherwise, many experts advocate for anaerobes coverage even with no documentation, given the sub-optimal sensitivity of current techniques. A 6-week combination of third-generation cephalosporin and metronidazole will cure most cases of community-acquired brain abscess in immunocompetent patients.

IMPLICATIONS

Significant advances in brain imaging, minimally invasive neurosurgery, molecular biology and antibacterial agents have dramatically improved the prognosis of brain abscess in immunocompetent patients over the last decades.