Spectrum and Prevalence of Pathological Intracranial Magnetic Resonance Imaging Findings in Acute Bacterial Meningitis

German guidelines on community-acquired acute bacterial meningitis in adults

INTRODUCTION

The incidence of community-acquired acute bacterial meningitis has decreased during the last decades. However, outcome remains poor with a significant proportion of patients not surviving and up to 50% of survivors suffering from long-term sequelae. These guidelines were developed by the Deutsche Gesellschaft für Neurologie (DGN) under guidance of the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF) to guide physicians through diagnostics and treatment of adult patients with acute bacterial meningitis.

RECOMMENDATIONS

The most important recommendations are: (i) In patients with suspected acute bacterial meningitis, we recommend that lumbar cerebrospinal fluid (with simultaneous collection of serum to determine the cerebrospinal fluid-serum glucose index and blood cultures) is obtained immediately after the clinical examination (in the absence of severely impaired consciousness, focal neurological deficits, and/or new epileptic seizures). (ii) Next, we recommend application of dexamethasone and empiric antibiotics intravenously. (iii) The recommended initial empiric antibiotic regimen consists of ampicillin and a group 3a cephalosporin (e.g., ceftriaxone). (iv) In patients with severely impaired consciousness, new onset focal neurological deficits (e.g. hemiparesis) and/or patients with newly occurring epileptic seizures, we recommend that dexamethasone and antibiotics are started immediately after the collection of blood; we further recommend that -if the imaging findings do not indicate otherwise -a lumbar CSF sample is taken directly after imaging. (v) Due to the frequent occurrence of intracranial and systemic complications, we suggest that patients with acute bacterial meningitis are treated at an intensive care unit in the initial phase of the disease. In the case of impaired consciousness, we suggest that this is done at an intensive care unit with experience in the treatment of patients with severe CNS diseases.

CONCLUSIONS

The German S2k-guidelines give up to date recommendations for workup, diagnostics and treatment in adult patients with acute bacterial meningitis.

[Meningitis in the Emergency Room]

Meningitis describes an inflammation of the meninges of the brain and spinal cord, which, depending on the etiology, can be a serious disease with high lethality. The suspicion of meningitis therefore requires rapid and adept action. In this paper, we explain the diagnostic and therapeutic approach to suspected meningitis in the emergency department.

Changes in the incidence of acute bacterial meningitis caused by Streptococcus pneumoniae and the implications of serotype replacement in children in Colombia after mass vaccination with PCV10

INTRODUCTION

Acute bacterial meningitis (ABM) is a public health problem. The disease has reemerged after the introduction of pneumococcal conjugate vaccines (PCVs) due to an increase in serotypes that are not covered. The objective was to determine the changes in the disease incidence before and after the introduction of the 10-valent vaccine (PCV10) in Colombia.

METHODS

This multicenter study was conducted in 17 hospitals in Colombia. Data were collected from January 2008 to December 2019 in 10 hospitals in Bogotá and from January 2017 to December 2019 in seven hospitals in Cali, Medellín and Cartagena. The data were grouped into three periods: 2008-2011, 2012-2015, and 2016-2019.

RESULTS

Of the 706 cases of invasive pneumococcal disease, 81 (11.4%) corresponded to meningitis. The relative incidence in Bogotá in the first period was 0.6 per 100,000 patients ≤ 5 years, decreased to 0.4 per 100,000 patients ≤ 5 years in the second period and increased in the third period to 0.7 per 100,000 patients ≤ 5 years. Serotypes covered by PCV10 decreased from 75 to 9.1%, with Spn19A (31.8%) and Spn34 (13.6%) emerging in the third period. Increased resistance to penicillin (13 to 37%) and to ceftriaxone (5.9 to 16%) was due to the emergence of multidrug-resistant Spn19A. The total mortality rate was 23.5% and increased from 12 to 33%.

CONCLUSIONS

ABM due to pneumococcus has high morbidity and mortality rates. Reemergence of the disease has been observed due to the inclusion of polymerase chain reaction (PCR) for diagnosis and replacement of circulating serotypes after the introduction of PCV10, with an increase in Spn19A, which causes death and exhibits antimicrobial resistance. Continued surveillance is needed.

Septic shock due to Escherichia coli meningoencephalitis treated with immunoglobulin-M-enriched immunoglobulin preparation as adjuvant therapy: a case report

BACKGROUND

Gram-negative bacteria are an uncommon etiology of spontaneous community-acquired adult meningitis and meningoencephalitis. Escherichia coli is a Gram-negative bacterium that is normally present in the intestinal microbial pool. Some Escherichia coli strains can cause diseases in humans and animals, with both intestinal and extraintestinal manifestations (extraintestinal pathogenic Escherichia coli) such as urinary tract infections, bacteremia with sepsis, and, more rarely, meningitis. Meningitis continues to be an important cause of mortality throughout the world, despite progress in antimicrobial chemotherapy and supportive therapy. The mortality rate fluctuates between 15% and 40%, and about 50% of the survivors report neurological sequelae. The majority of Escherichia coli meningitis cases develop as a result of hematogenous spread, with higher degrees of bacteremia also being related to worse prognosis. Cases presenting with impaired consciousness (that is, coma) are also reported to have poorer outcomes.

CASE PRESENTATION

We describe the case of a 48-year-old caucasian woman with meningoencephalitis, with a marked alteration of consciousness on admission, and septic shock secondary to pyelonephritis caused by Escherichia coli, treated with targeted antimicrobial therapy and immunoglobulin-M-enriched immunoglobulin (Pentaglobin) preparation as adjuvant therapy.

CONCLUSION

Despite the dramatic presentation of the patient on admission, the conflicting data on the use of immunoglobulins in septic shock, and the lack of evidence regarding their use in adult Escherichia coli meningoencephalitis, we obtained a remarkable improvement of her clinical condition, accompanied by partial resolution of her neurological deficits.

The value of contrast-enhanced FLAIR magnetic resonance imaging in detecting meningeal abnormalities in suspected cases of meningitis compared to conventional contrast-enhanced T1WI sequences

Background

Early diagnosis of meningitis with magnetic resonance imaging (MRI) would be useful for appropriate and effective management, decrease morbidity and mortality, and provide better diagnosis and treatment. The objective of the current study is to compare the accuracy of contrast-enhanced FLAIR (CE-FLAIR) and contrast-enhanced T1WI (CE-T1WI) in the detection of meningeal abnormalities in suspected cases of meningitis.

Results

Out of 45 patients, 37 patients were confirmed to have meningitis on CSF analysis. Out of the 37 patients, 34 patients were positive on CE-FLAIR sequence and 27 were positive on CE-T1WI. The sensitivity of CE-FLAIR sequence was 91.9% and specificity 100%, while the sensitivity of CE-T1WI sequence was 73% and specificity 100%.

Conclusion

CE-FLAIR is more sensitive than CE-T1WI in diagnosis of meningitis. It is recommended to be used in any cases with clinically suspected meningitis.

Infections causing stroke or stroke-like syndromes

BACKGROUND

Stroke has relevant morbidity and mortality despite appropriate treatments and early diagnosis. Beside common risk factors such as diabetes and atrial fibrillation, infections can be involved in stroke pathogenesis, probably causing a systemic release of cytokines and other inflammatory mediators, triggering a latent pro-thrombotic state or damaging the vascular endothelium. In other cases, infections can occur as stroke-like syndromes, requiring a high grade of suspicion to avoid a delay in establishing a correct diagnosis.

RESULTS

Treatment of stroke or stroke-like syndromes of infectious origin can be difficult. When a previous infective event triggers stroke, Alteplase administration can be associated with a higher incidence of bleeding and the extension of the ischaemic area can be major than expected. On the other hand, when stroke is part of some infectious diseases' presentation as in endocarditis, bacterial or tuberculous meningitis and meningo-vascular syphilis, a correct diagnosis can be difficult. The management of these stroke-like syndromes is not standardised because common treatments proven to be effective for patients with stroke of vascular origin can worsen the prognosis, as it can be demonstrated after to be incorrect Alteplase administration to patients with endocarditis with septic embolism to the brain is associated with an increase of the risk of haemorrhage.

CONCLUSIONS

Stroke or stroke-like syndrome of infectious origin can be observed in an important proportion of case presenting with sensory-motor deficit of unknown origin; their accurate diagnosis has a considerable impact in terms of treatment choices and outcome.

Contrast-enhanced modified 3D T1-weighted TSE black-blood imaging can improve detection of infectious and neoplastic meningitis

OBJECTIVES

To evaluate the diagnostic value of a contrast-enhanced 3D T1-weighted-modified volumetric isotropic turbo spin-echo acquisition sequence (T1-mVISTA) in comparison with a conventional 3D T1-weighted magnetization-prepared rapid gradient-echo (T1-MP-RAGE) sequence for the detection of meningeal enhancement in patients with meningitis.

METHODS

Thirty patients (infectious meningitis, n = 12; neoplastic meningitis, n = 18) and 45 matched controls were enrolled in this retrospective case-control study. Sets of randomly selected T1-mVISTA and T1-MP-RAGE images (both with 0.8-mm isotropic resolution) were read separately 4 weeks apart. Image quality, leptomeningeal and dural enhancement, grading of visual contrast enhancement, and diagnostic confidence were compared using the Kruskal-Wallis rank sum test.

RESULTS

Image quality was rated to be good to excellent in 75 out of 75 cases (100%) for T1-mVISTA and 74 out of 75 cases (98.7%) for T1-MP-RAGE. T1-mVISTA detected significantly more patients with leptomeningeal enhancement (p = 0.006) compared with T1-MP-RAGE (86.7 vs. 50.0%, p < 0.001), each with specificity of 100%. Similarly, sensitivity of T1-mVISTA for the detection of dural and/or leptomeningeal enhancement was also significantly higher compared with that of T1-MP-RAGE (96.7 vs. 80.0%, p = 0.025) without significant differences regarding specificity (97.8 vs. 95.6%, p = 0.317). No significant differences were found for dural enhancement alone. Diagnostic confidence in T1-mVISTA was significantly higher (p = 0.01). Visual contrast enhancement was tendentially higher in T1-mVISTA.

CONCLUSIONS

T1-mVISTA may be an adequate and probably better alternative to T1-MP-RAGE for detection of leptomeningeal diseases.

KEY POINTS

• Black-blood T1-mVISTA showed a significant higher sensitivity for the detection of leptomeningeal enhancement compared with MP-RAGE without losses regarding specificity. • Diagnostic confidence was assessed significantly higher in T1-mVISTA. • T1-mVISTA should be considered a supplement or an alternative to T1-MP-RAGE in patients with suspected leptomeningeal diseases.

[The duration of antibiotic therapy in bacterial meningitis with pyogenic ventriculitis]

A 68-year-old man visited our hospital emergency department with consciousness disturbance. He was diagnosed as bacterial meningitis with septic shock, and initial empirical antibacterial therapy was initiated immediately. Streptococcus pneumoniae. was cultured from the cerebrospinal fluid (CSF), and brain MRIs showed pyogenic ventriculitis. Even though CSF findings improved, he was still in coma and finally died with pneumonia. It is unknown how pyogenic ventriculitis affects the course of bacterial meningitis. We analyzed total 11 inpatients with bacterial meningitis associated with or without the pyogenic ventriculitis, including the present patient, in our hospital. Severity of clinical symptoms and CSF findings might determine the duration of antimicrobial administration, regardless of whether pyogenic ventriculitis existed or not.

Late Recovery from Severe Streptococcus pneumoniae Comatose Meningitis with Concomitant Diffuse Subcortical Cytotoxic Edema and Cortical Hypometabolism

A 75-year-old woman was admitted to ICU with coma following Streptococcus pneumoniae meningitis with bacteremia. Her Glasgow Coma Scale (GCS) score fluctuated around 4 to 6 over the next four weeks. There was no evidence of increased intracranial pressure (ICP). Electroencephalogram (EEG) showed only diffuse aspecific slowing. Impaired cerebral blood flow (CBF) autoregulation was suggested at transcranial Doppler (TCD). Repeated brain magnetic resonance imaging (MRI) examination failed to demonstrate venous thrombosis, arterial ischemic stroke, or brain abscesses but revealed diffuse but reversible cortical cytotoxic edema at diffusion-weighted (DW) sequences. The brain FDG-positron emission tomography (FDG-PET) showed diffuse cortical hypometabolism. The patient unexpectedly experienced a complete neuropsychological recovery the next few weeks. The suggested hypothesis to explain this unusual disease course could be a transient alteration of CBF autoregulation due to some degree of diffuse subcortical microangiopathy. A concomitant reduction of brain metabolism probably prevented the progression towards cortical irreversible ischemic damage.

Imaging in Lyme neuroborreliosis

Abstract

Lyme neuroborreliosis (LNB) is a tick-borne spirochetal infection with a broad spectrum of imaging pathology. For individuals who live in or have travelled to areas where ticks reside, LNB should be considered among differential diagnoses when clinical manifestations from the nervous system occur. Radiculitis, meningitis and facial palsy are commonly encountered, while peripheral neuropathy, myelitis, meningoencephalitis and cerebral vasculitis are rarer manifestations of LNB. Cerebrospinal fluid (CSF) analysis and serology are key investigations in patient workup. The primary role of imaging is to rule out other reasons for the neurological symptoms. It is therefore important to know the diversity of possible imaging findings from the infection itself. There may be no imaging abnormality, or findings suggestive of neuritis, meningitis, myelitis, encephalitis or vasculitis. White matter lesions are not a prominent feature of LNB. Insight into LNB clinical presentation, laboratory test methods and spectrum of imaging pathology will aid in the multidisciplinary interaction that often is imperative to achieve an efficient patient workup and arrive at a correct diagnosis. This article can educate those engaged in imaging of the nervous system and serve as a comprehensive tool in clinical cases.

Key Points

• Diagnostic criteria for LNB emphasise exclusion of an alternative cause to the clinical symptoms.

• MRI makes a crucial contribution in the diagnosis and follow-up of LNB.

• MRI may have normal findings, or show neuritis, meningitis, myelitis, encephalitis or vasculitis.

• White matter lesions are not a prominent feature of LNB.

Global etiology of bacterial meningitis: A systematic review and meta-analysis

Bacterial meningitis is a global public health concern, with several responsible etiologic agents that vary by age group and geographical area. The aim of this systematic review and meta-analysis was to assess the etiology of bacterial meningitis in different age groups across global regions. PubMed and EMBASE were systematically searched for English language studies on bacterial meningitis, limited to articles published in the last five years. The methodological quality of the studies was assessed using a customized scoring system. Meta-analyses were conducted to determine the frequency (percentages) of seven bacterial types known to cause meningitis: Escherichia coli, Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae, group B Streptococcus agalactiae, Staphylococcus aureus, and Listeria monocytogenes, with results being stratified by six geographical regions as determined by the World Health Organization, and seven age groups. Of the 3227 studies retrieved, 56 were eligible for the final analysis. In all age groups, S. pneumoniae and N. meningitidis were the predominant pathogens in all regions, accounting for 25.1-41.2% and 9.1-36.2% of bacterial meningitis cases, respectively. S. pneumoniae infection was the most common cause of bacterial meningitis in the 'all children' group, ranging from 22.5% (Europe) to 41.1% (Africa), and in all adults ranging from 9.6% (Western Pacific) to 75.2% (Africa). E. coli and S. pneumoniae were the most common pathogens that caused bacterial meningitis in neonates in Africa (17.7% and 20.4%, respectively). N. meningitidis was the most common in children aged ±1-5 years in Europe (47.0%). Due to paucity of data, meta-analyses could not be performed in all age groups for all regions. A clear difference in the weighted frequency of bacterial meningitis cases caused by the different etiological agents was observed between age groups and between geographic regions. These findings may facilitate bacterial meningitis prevention and treatment strategies.

Diagnosis of Meningitis Caused by Pathogenic Microorganisms Using Magnetic Resonance Imaging: A Systematic Review

Introduction:

Bacterial meningitis is an acute infectious inflammation of the protective membranes covering the brain. Its early diagnosis is vital because of its high morbidity and mortality. It is mostly diagnosed by a gold standard diagnostic tool i.e. Cerebrospinal Fluid (CSF) analysis. However, it is sometimes difficult and or impossible to do this procedure and an alternative diagnostic tool is needed. Contrast enhanced magnetic resonance imaging can detect the pus or other changes in subarachnoid space. But our optimal aim is to use an imaging method without using contrast to be useable and available in more specific condition.

Methods:

This study aimed to survey the role of non-contrast Magnetic Resonance Imaging (MRI) in the diagnosis of the bacterial meningitis. MEDLINE/PubMed Central, Web of Science and Scopus were searched without time period and language limitation until March 2017. We found 6410 papers in our initial search. After assessing the content of the papers based on Cochrane library guidelines and inclusion/exclusion criteria, 6 relevant studies were included in the systematic review. All of included studies were observational studies.

Results:

MRI studies demonstrated that Fluid Attenuation Inversion Recovery (FLAIR) and Diffusion-Weighted Image (DWI) MR imaging among all MRI modalities can detect some abnormalities compatible with bacterial meningitis. FLAIR and DWI-MR imaging are potentially useful to diagnose bacterial meningitis and can be used in emergent condition in which bacterial meningitis is highly suspicious and the other diagnostic tools are not available or feasible.

Diffusion-weighted MRI abnormalities in an outbreak of Streptococcus agalactiae Serotype III, multilocus sequence type 283 meningitis

PURPOSE

In 2015, an outbreak of group B streptococcal (GBS) infection caused by Streptococcus agalactiae Serotype III, multilocus sequence type 283, related to consuming infected raw freshwater fish, affected more than 200 patients in Singapore. We describe the clinical, laboratory, and neuroimaging features of a subgroup of adults with central nervous system (CNS) infections caused by GBS.

MATERIALS AND METHODS

The database of the Singapore Neurologic Infections Program (SNIP), a national multicenter study for surveillance of infectious neurologic disease, was reviewed to select patients with GBS CNS infection during the outbreak. Cases were diagnosed on the basis of clinical features, cerebrospinal fluid (CSF) findings and identification or isolation of Streptococcus agalactiae in the blood or CSF. Demographic, clinical and neuroradiological information was obtained prospectively and retrospectively abstracted.

RESULTS

Fourteen patients (6 male, 8 female; median age, 58 years) presented with fever, meningism, headache, encephalopathy, focal neurological deficits, and/or seizures. All except two were previously healthy. Diffusion-weighted imaging (DWI) on admission was abnormal in 13 patients, showing tiny hyperintensities in the subarachnoid space (7 patients), ventricles (6 patients) and brain parenchyma (8 patients); 5 patients had cerebellar abnormalities.

CONCLUSION

Among healthy non-pregnant adults infected with Serotype III, multilocus sequence type 283 GBS meningitis linked to eating infected raw freshwater fish, DWI detected small pus collections and unusual cerebellar involvement. A collaborative national surveillance system that includes MRI can be helpful during unusual food-borne zoonotic infectious disease outbreaks.

LEVEL OF EVIDENCE

4 J. Magn. Reson. Imaging 2017;45:507-514.

A case of meningococcal meningitis with multiple cerebellar microbleeds detected by susceptibility-weighted imaging

Background

Bacterial meningitis is a fatal infectious disease of the central nervous system complicating intravascular involvements. Multiple microbleeds are rarely identified as complications because of the limited detection threshold of conventional imaging modalities. We report the first case of meningococcal meningitis with successful identification of multiple microbleeds in the cerebellum by susceptibility-weighted imaging.

Case presentation

A 19-year-old Japanese female was brought to our emergency department because of fever and coma. A spinal tap was performed and turbid yellow fluid was collected. A diagnosis of bacterial meningitis was established and the patient was admitted to an intensive care unit. Dexamethasone and Antibiotics were administered and Neisseria meningitides was cultured from the spinal fluid. On day 10, postcontrast magnetic resonance imaging identified enhanced subarachnoid space in the cerebellum. Susceptibility-weighted imaging showed spotty low-intensity signals in the cerebellar tissue, indicating microbleeds. The patient made a full recovery from coma and was discharged without neurological sequelae on day 24.

Conclusion

Meningococcal meningitis can cause multiple microbleeds in the cerebellum. In this report, we successfully identified microbleeds by susceptibility-weighed imaging. Using this imaging modality, further investigations will clarify its clinical incidence and significance.