Pulmonary arteriovenous malformations in patients with previous brain abscess: a cross-sectional population-based study.

BACKGROUND AND PURPOSE: Pulmonary arteriovenous malformations (PAVMs) may cause recurrent brain abscess. The primary aim was to determine the prevalence of PAVM amongst survivors of brain abscess. The proportion with cardiac right-to-left shunts was also assessed post hoc. METHODS: This was a cross-sectional population-based study of adult (≥18 years) survivors of cryptogenic bacterial brain abscess in Denmark from 2007 through 2016. Patients were invited for bubble-echocardiography to detect vascular right-to-left shunting and, if abnormal, subsequent computed tomography thorax for diagnosis of PAVM. Data are presented as n/N (%) or median with interquartile range (IQR). RESULTS: Study participation was accepted by 47/157 (30%) eligible patients amongst whom two did not appear for scheduled bubble-echocardiography. The median age of participants was 54 years (IQR 45-62) and 19/57 (33%) were females compared with 59 years (IQR 48-68, p = 0.05) and 41/85 females (48%, p = 0.22) in non-participants. Bubble-echocardiography was suggestive of shunt in 10/45 (22%) participants and PAVM was subsequently confirmed by computed tomography in one patient with grade 1 shunting. The corresponding prevalence of PAVM was 2% (95% confidence interval 0.06-11.8) amongst all examined participants. Another 9/45 (20%) were diagnosed with patent in persistent foramen ovale (n = 8) or atrial septum defect (n = 1), which is comparable with the overall prevalence of 25% amongst adults in the Danish background population. CONCLUSIONS: Undiagnosed PAVM amongst adult survivors of cryptogenic bacterial brain abscess is rare but may be considered in select patients. The prevalence of cardiac right-to-left shunts amongst brain abscess patients corresponds to the prevalence in the general population.

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

BACKGROUND: Oral cavity bacteria are the most frequent etiology of brain abscess. Yet, data on the clinical presentation and outcome are scarce. METHODS: We performed a nationwide, population-based study comprising all adults (aged ≥18 years) with brain abscess due to oral cavity bacteria in Denmark from 2007 through 2020. Prognostic factors for unfavorable outcome (Glasgow outcome scale, 1-4) were examined using modified Poisson regression to compute adjusted relative risks (RRs) with 95% confidence intervals (CIs). RESULTS: Among 287 identified patients, the median age was 58 years (interquartile range, 47-66), and 96 of 287 (33%) were female. Preexisting functional impairment was absent or mild in 253 of 280 (90%), and risk factors for brain abscess included immunocompromise in 95 of 287 (33%), dental infection in 68 of 287 (24%), and ear-nose-throat infection in 33 of 287 (12%). Overall, a neurological deficit was present in 246 of 276 (86%) and in combination with headache and fever in 64 of 287 (22%). Identified microorganisms were primarily the Streptococcus anginosus group, Fusobacterium, Actinomyces, and Aggregatibacter spp., and 117 of 287 (41%) were polymicrobial. Unfavorable outcome occurred in 92 of 246 (37%) at 6 months after discharge and was associated with antibiotics before neurosurgery (RR, 3.28; 95% CI, 1.53-7.04), rupture (RR, 1.89; 95% CI, 1.34-2.65), and immunocompromise (RR, 1.80; 95% CI, 1.29-2.51), but not with specific targeted antibiotic regimens. Identified dental infection was associated with favorable prognosis (RR, 0.58; 95% CI, .36-.93). CONCLUSIONS: Brain abscess due to oral cavity bacteria often occurred in previously healthy individuals without predisposing dental infections. Important risk factors for unfavorable outcome were rupture and immunocompromise. However, outcome was not associated with specific antibiotic regimens supporting carbapenem-sparing strategies.

Benign recurrent lymphocytic meningitis (Mollaret's meningitis) in Denmark: a nationwide cohort study.

BACKGROUND AND PURPOSE: Data on clinical features and outcomes of benign recurrent lymphocytic meningitis (BRLM) are limited. METHODS: This was a nationwide population-based cohort study of all adults hospitalized for BRLM associated with herpes simplex virus type 2 (HSV-2) at the departments of infectious diseases in Denmark from 2015 to 2020. Patients with single-episode HSV-2 meningitis were included for comparison. RESULTS: Forty-seven patients with BRLM (mean annual incidence 1.2/1,000,000 adults) and 118 with single-episode HSV-2 meningitis were included. The progression risk from HSV-2 meningitis to BRLM was 22% (95% confidence interval [CI] 15%-30%). The proportion of patients with the triad of headache, neck stiffness and photophobia/hyperacusis was similar between BRLM and single-episode HSV-2 meningitis (16/43 [37%] vs. 46/103 [45%]; p = 0.41), whilst the median cerebrospinal fluid leukocyte count was lower in BRLM (221 cells vs. 398 cells; p = 0.02). Unfavourable functional outcomes (Glasgow Outcome Scale score of 1-4) were less frequent in BRLM at all post-discharge follow-up visits. During the study period, 10 (21%) patients with BRLM were hospitalized for an additional recurrence (annual rate 6%, 95% CI 3%-12%). The hazard ratio for an additional recurrence was 3.93 (95% CI 1.02-15.3) for patients with three or more previous episodes of meningitis. CONCLUSIONS: Clinical features of BRLM were similar to those of single-episode HSV-2 meningitis, whilst post-discharge outcomes were more favourable. Patients with three or more previous episodes of meningitis had higher risk of an additional recurrence.

Viral lumbosacral radiculitis (Elsberg syndrome) in Denmark.

PURPOSE: To describe clinical features and outcomes of viral lumbosacral radiculitis (Elsberg syndrome). METHODS: Nationwide population-based cohort study of all adults hospitalised for viral lumbosacral radiculitis at departments of infectious diseases in Denmark from 2015 to 2020. RESULTS: Twenty-eight patients with viral lumbosacral radiculitis were included (mean annual incidence: 1.2/1,000,000 adults). The median age was 35 years (IQR 27-43), and 22/28 (79%) were female. All patients had urinary retention, with 17/28 (61%) needing a catheter. On admission, at least one sign or symptom of meningitis (headache, neck stiffness, photophobia/hyperacusis) was present in 18/22 (82%). Concurrent genital herpetic lesions were present in 11/24 (46%). The median cerebrospinal fluid leukocyte count was 153 cells/µL (IQR 31-514). Magnetic resonance imaging showed radiculitis/myelitis in 5/19 (26%). The microbiological diagnosis was herpes simplex virus type 2 in 19/28 (68%), varicella-zoster virus in 2/28 (7%), and unidentified in 7/28 (25%). Aciclovir/valaciclovir was administered in 27/28 (96%). At 30 days after discharge, 3/27 (11%) had persistent urinary retention with need of catheter. At 180 days after discharge, moderate disabilities (Glasgow Outcome Scale score of 4) were observed in 5/25 (20%). CONCLUSIONS: Urinary retention resolved within weeks in most patients with viral lumbosacral radiculitis, but moderate disabilities according to the Glasgow Outcome Scale were common at the end of follow-up.

Hearing Loss in Bacterial Meningitis Revisited-Evolution and Recovery.

Background: Hearing loss and deafness are well-known sequelae from bacterial meningitis (ABM) and may result in social dysfunction and learning difficulties. Yet, the timely development of hearing loss and restitution is poorly studied, especially among adults. Hearing loss was revisited using otoacoustic emissions (OAEs) to determine the occurrence, magnitude, and development of hearing loss among adults with ABM. Methods: Distortion product OAEs were measured in patients with ABM the day of admission and days 2, 3, 5-7, and 10-14 and at follow-up 30-60 days after discharge. Frequencies were categorized as low (1, 1.5, 2 kHz), mid (3, 4, 5 kHz), mid-high (6, 7, 8 kHz), and high (9, 10 kHz). Audiometry was performed on discharge and 60 days after. Results were compared with 158 healthy controls. Results: OAE was obtained in 32 patients. ABM was due to S. pneumoniae in 12 patients (38%). All patients were treated with dexamethasone. OAE emission threshold levels (ETLs) were significantly decreased upon admission and at follow-up in all frequencies compared with healthy controls. A substantial and significant decrease in ETLs was found in S. pneumoniae meningitis. Sensorineural hearing loss (SNHL) >20 dB was present in 13 of 23 (57%) at discharge and in 11 of 18 patients (61%) 60 days after discharge. Hearing recovery decreased from day 3. Conclusions: Hearing loss in ABM still affects >60% of patients despite treatment with dexamethasone. In S. pneumoniae meningitis, SNHL is profound and permanent. A window of opportunity for systemic or local treatments aiming to preserve cochlear function is proposed.

Pentraxin 3 in the cerebrospinal fluid during central nervous system infections: A retrospective cohort study.

The present study describes diagnostic and prognostic abilities of Cerebrospinal fluid (CSF) Pentraxin 3 (PTX3) in central nervous system (CNS) infections. CSF PTX3 was measured retrospectively from 174 patients admitted under suspicion of CNS infection. Medians, ROC curves and Youdens index was calculated. CSF PTX3 was significantly higher among all CNS infections and undetectable in most of the patients in the control group, and significantly higher in bacterial infections compared to viral and Lyme infections. No association was found between CSF PTX3 and Glasgow Outcome Score. PTX3 in the CSF can distinguish bacterial infection from viral and Lyme infections and non-CNS infections. Highest levels were found in bacterial meningitis. No prognostic abilities were found.

Clinical features and prognostic factors in adults with viral meningitis.

Clinical features applicable to the entire spectrum of viral meningitis are limited, and prognostic factors for adverse outcomes are undetermined. This nationwide population-based prospective cohort study included all adults with presumed and microbiologically confirmed viral meningitis in Denmark from 2015 until 2020. Prognostic factors for an unfavourable outcome (Glasgow Outcome Scale score of 1-4) 30 days after discharge were examined by modified Poisson regression. In total, 1066 episodes of viral meningitis were included, yielding a mean annual incidence of 4.7 episodes per 100 000 persons. Pathogens were enteroviruses in 419/1066 (39%), herpes simplex virus type 2 in 171/1066 (16%), varicella-zoster virus in 162/1066 (15%), miscellaneous viruses in 31/1066 (3%) and remained unidentified in 283/1066 (27%). The median age was 33 years (IQR 27-44), and 576/1066 (54%) were females. In herpes simplex virus type 2 meningitis, 131/171 (77%) were females. Immunosuppression [32/162 (20%)] and shingles [90/149 (60%)] were frequent in varicella-zoster virus meningitis. The triad of headache, neck stiffness and hyperacusis or photophobia was present in 264/960 (28%). The median time until lumbar puncture was 3.0 h (IQR 1.3-7.1), and the median CSF leucocyte count was 160 cells/µl (IQR 60-358). The outcome was unfavourable in 216/1055 (20%) 30 days after discharge. Using unidentified pathogen as the reference, the adjusted relative risk of an unfavourable outcome was 1.34 (95% CI 0.95-1.88) for enteroviruses, 1.55 (95% CI 1.00-2.41) for herpes simplex virus type 2, 1.51 (95% CI 0.98-2.33) for varicella-zoster virus and 1.37 (95% CI 0.61-3.05) for miscellaneous viruses. The adjusted relative risk of an unfavourable outcome was 1.34 (95% CI 1.03-1.75) for females. Timing of acyclovir or valacyclovir was not associated with the outcome in meningitis caused by herpes simplex virus type 2 or varicella-zoster virus. In summary, the outcome of viral meningitis was similar among patients with different aetiologies, including those with presumed viral meningitis but without an identified pathogen. Females had an increased risk of an unfavourable outcome. Early antiviral treatment was not associated with an improved outcome in meningitis caused by herpes simplex virus type 2 or varicella-zoster virus.

Risk Factors and Prognosis of Epilepsy Following Brain Abscess: A Nationwide Population-Based Cohort Study.

BACKGROUND AND OBJECTIVES: Epilepsy in patients with brain abscess is frequent, but risk factors and prognosis remain undetermined. This study examined risk factors of epilepsy among survivors of brain abscess and associated prognosis. METHODS: Nationwide, population-based healthcare registries were used to compute cumulative incidences and cause-specific adjusted hazard rate ratios (adj. HRRs) with 95% CIs for epilepsy among 30-day survivors of brain abscess from 1982 through 2016. Data were enriched with clinical details by medical record review of patients hospitalized from 2007 through 2016. Adjusted mortality rate ratios (adj. MRRs) were examined using epilepsy as a time-dependent variable. RESULTS: The study included 1,179 30-day survivors of brain abscess among whom 323 (27%) developed new-onset epilepsy after a median of 0.76 years (interquartile range [IQR] 0.24-2.41). At admission for brain abscess, the median age was 46 years (IQR 32-59) in patients with epilepsy compared with 52 years (IQR 33-64) in those without epilepsy. The proportion of female individuals was similar in patients with and without epilepsy (37%). Adj. HRRs for epilepsy were 2.44 (95% CI 1.89-3.15) for aspiration or excision of brain abscess, 2.37 (1.56-3.60) for alcohol abuse, 1.75 (1.27-2.40) for previous neurosurgery or head trauma, 1.62 (1.17-2.25) for stroke, and 1.55 (1.04-2.32) for age group 20-39 years. Cumulative incidences were increased in patients with alcohol abuse (52% vs 31%), aspiration or excision of brain abscess (41% vs 20%), previous neurosurgery or head trauma (41% vs 31%), and stroke (46% vs 31%). Analysis using clinical details from medical record review of patients from 2007 through 2016 demonstrated adj. HRRs of 3.70 (2.24-6.13) for seizures at admission for brain abscess and 1.80 (1.04-3.11) for frontal lobe abscess. By contrast, adj. HRR was 0.42 (0.21-0.86) for occipital lobe abscess. Using the entire registry-based cohort, patients with epilepsy had an adj. MRR of 1.26 (1.01-1.57). DISCUSSION: Important risk factors of epilepsy were seizures during admission for brain abscess, neurosurgery, alcoholism, frontal lobe abscess, and stroke. Epilepsy was associated with an increased mortality. Antiepileptic treatment may be guided by individual risk profiles, and a specialized follow-up is highlighted by an increased mortality in survivors with epilepsy.

Clinical features and prognostic factors in adults with brain abscess.

Studies on brain abscess are hampered by single-centre design with limited sample size and incomplete follow-up. Thus, robust analyses on clinical prognostic factors remain scarce. This Danish nationwide, population-based cohort study included clinical details of all adults (≥18 years) diagnosed with brain abscess in the Danish National Patient Registry from 2007 through 2014 and the prospective clinical database of the Danish Study Group of Infections of the Brain covering all Danish departments of infectious diseases from 2015 through 2020. All patients were followed for 6 months after discharge. Prognostic factors for mortality at 6 months after discharge were examined by adjusted modified Poisson regression to compute relative risks with 95% confidence intervals (CI). Among 485 identified cases, the median age was 59 years [interquartile range (IQR 48-67)] and 167 (34%) were female. The incidence of brain abscess increased from 0.4 in 2007 to 0.8 per 100 000 adults in 2020. Immuno-compromise was prevalent in 192/485 (40%) and the clinical presentation was predominated by neurological deficits 396/485 (82%), headache 270/411 (66%), and fever 208/382 (54%). The median time from admission until first brain imaging was 4.8 h (IQR 1.4-27). Underlying conditions included dental infections 91/485 (19%) and ear, nose and throat infections 67/485 (14%), and the most frequent pathogens were oral cavity bacteria (59%), Staphylococcus aureus (6%), and Enterobacteriaceae (3%). Neurosurgical interventions comprised aspiration 356/485 (73%) or excision 7/485 (1%) and was preceded by antibiotics in 377/459 (82%). Fatal outcome increased from 29/485 (6%) at discharge to 56/485 (12%) 6 months thereafter. Adjusted relative risks for mortality at 6 months after discharge was 3.48 (95% CI 1.92-6.34) for intraventricular rupture, 2.84 (95% CI 1.45-5.56) for immunocompromise, 2.18 (95% CI 1.21-3.91) for age >65 years, 1.81 (95% CI 1.00-3.28) for abscess diameter >3 cm, and 0.31 (95% CI 0.16-0.61) for oral cavity bacteria as causative pathogen. Sex, neurosurgical treatment, antibiotics before neurosurgery, and corticosteroids were not associated with mortality. This study suggests that prevention of rupture of brain abscess is crucial. Yet, antibiotics may be withheld until neurosurgery, if planned within a reasonable time period (e.g. 24 h), in some clinically stable patients. Adjunctive corticosteroids for symptomatic perifocal brain oedema was not associated with increased mortality.

Existing Data Sources for Clinical Epidemiology: The Danish Study Group of Infections of the Brain Database (DASGIB).

Central nervous system (CNS) infections are rare diseases that are associated with considerable morbidity and mortality. Increased knowledge based on contemporary data is a prerequisite for improved management and prevention of these serious conditions. Yet, population-based databases of patients hospitalized with CNS infections remain scarce. The Danish Study Group of Infections of the Brain (DASGIB) has prospectively registered information on all adults ≥18 years of age admitted with CNS infections at departments of infectious diseases in Denmark since 2015. The main variables collected are baseline demographics, blood and cerebrospinal fluid tests, imaging results, and outcome using the Glasgow Outcome Scale score. To investigate important aspects for each type of CNS infections, additional variables are included specifically for bacterial meningitis, viral meningitis, encephalitis, brain abscess, neurosyphilis, and Lyme neuroborreliosis. From 2015 to 2020, a total of 3579 cases of CNS infections have been recorded in the DASGIB database. Using the unique civil registration number assigned to all Danish residents, the database can be unambiguously linked with nationwide healthcare registries at the individual level. This enables researchers to conduct detailed population-based and longitudinal observational studies of risk and prognosis of CNS infections and to compare them with matched population cohorts. The database is well-suited for epidemiological research and the DASGIB network forms a solid infrastructure for future national and international collaborations.

Enterovirus Meningitis in Adults: A Prospective Nationwide Population-Based Cohort Study.

OBJECTIVE: To test the hypothesis that enterovirus meningitis (EM) is a frequent and self-limiting condition, the epidemiology of EM in adults was examined. METHODS: Using a prospective, nationwide, population-based database, all adults with EM confirmed by PCR of the CSF from 2015 to 2019 were included. Unfavorable outcome was defined as Glasgow Outcome Scale scores of 1-4 at discharge. Modified Poisson regression was used to compute adjusted relative risks (RRs). RESULTS: A total of 419 cases of EM in 418 adults (46% female, median age 31 years [interquartile range (IQR) 27-35]) yielded an incidence of 1.80/100,000/year. Admission diagnoses included CNS infection 247/397 (62%), other neurologic conditions 89/397 (22%), and cerebrovascular diseases 33/397 (8%). Genotype was available for 271 cases, of which echovirus 30 accounted for 155 (57%). Patients presented with headache 412/415 (99%), history of fever 303/372 (81%), photophobia 292/379 (77%), and neck stiffness 159/407 (39%). Fever (≥38.0°C) was observed in 192/399 (48%) at admission. The median CSF leukocyte count was 130 106/L (range 0-2,100) with polymorphonuclear predominance (>50%) in 110/396 (28%). Cranial imaging preceded lumbar puncture in 127/417 (30%) and was associated with non-CNS infection admission diagnoses and delayed lumbar puncture (median 4.8 hours [IQR 3.4-7.9] vs 1.5 [IQR 0.8-2.8], p < 0.001). Unfavorable outcome occurred in 99/419 (24%) at discharge; more often in female patients (RR 2.30 [1.58-3.33]) and less frequent in echovirus 30 (RR 0.67 [0.46-1.00]) in adjusted analyses. Outcome remained unfavorable in 22/379 (6%) after 6 months. CONCLUSIONS: EM is common among young, healthy adults. Although the long-term prognosis remains reassuring, a substantial proportion have moderate disability at discharge, especially female patients.

Defects in LC3B2 and ATG4A underlie HSV2 meningitis and reveal a critical role for autophagy in antiviral defense in humans.

Recurrent herpesvirus infections can manifest in different forms of disease, including cold sores, genital herpes, and encephalitis. There is an incomplete understanding of the genetic and immunological factors conferring susceptibility to recurrent herpes simplex virus 2 (HSV2) infection in the central nervous system (CNS). Here, we describe two adult patients with recurrent HSV2 lymphocytic Mollaret's meningitis that each carry a rare monoallelic variant in the autophagy proteins ATG4A or LC3B2. HSV2-activated autophagy was abrogated in patient primary fibroblasts, which also exhibited significantly increased viral replication and enhanced cell death. HSV2 antigen was captured in autophagosomes of infected cells, and genetic inhibition of autophagy by disruption of autophagy genes, including ATG4A and LC3B2, led to enhanced viral replication and cell death in primary fibroblasts and a neuroblastoma cell line. Activation of autophagy by HSV2 was sensitive to ultraviolet (UV) irradiation of the virus and inhibited in the presence of acyclovir, but HSV2-induced autophagy was independent of the DNA-activated STING pathway. Reconstitution of wild-type ATG4A and LC3B2 expression using lentiviral gene delivery or electroporation of in vitro transcribed mRNA into patient cells restored virus-induced autophagy and the ability to control HSV2 replication. This study describes a previously unknown link between defective autophagy and an inborn error of immunity that can lead to increased susceptibility to HSV2 infection, suggesting an important role for autophagy in antiviral immunity in the CNS.

Severe acute hepatitis E infection presenting with acute abdomen and meningoencephalitis.

We present a case of a 50-year-old man admitted due to acute abdomen, icterus and fever. The patient had a history of sufficiently treated type 2 diabetes and a high daily alcohol consumption, no recent travel history and had a strictly heterosexual and monogamous way of living. A full blood count displayed severe elevated liver enzymes. A CT of the abdomen was performed and revealed steatosis but no acute abdominal pathology. During admission, the patient developed signs of meningoencephalitis. A lumbar puncture was performed, and the cerebrospinal fluid revealed lymphocytic pleocytosis consistent with mild inflammation. Furthermore, hepatitis E was found in the blood and the definitive diagnosis was established. The patient gradually recovered and was discharged within 8 days of admission. To the best of our knowledge, we present the second case describing concomitant hepatitis and meningoencephalitis, resolving spontaneously and not giving rise to sequelae.

Otoacoustic emissions in patients with bacterial meningitis.

Objective: Systematic evaluation of studies using otoacoustic emissions (OAEs) to monitor cochlear damage in patients with bacterial meningitis.Design: Systematic review. This includes articles retrieved from PUBMED and EMBASE. The search-strategy was based on the PICO-model. Data processing involved Cochrane Public Health Data Extraction template in addition to assessment of risk of bias and applicability with the Second Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool.Study samples: Thirty-eight articles were identified with 6 studies comprising 391 children and 17 adult patients eligible for full assessment.Results: Studies were heterogenic and the timing of OAE was incomparable between studies. The frequency of severe loss of hearing was reported to occur between 1.6 and 21% of the patients with culture-proven meningitis. The included studies, albeit heterogenic, found OAE-screening feasible and sensitive in children recovering from bacterial meningitis.Conclusion: No children with hearing loss were reported to pass an OAE screening in any of the included studies. The timing, sensitivity and extent of sensorineural hearing loss determined by OAE could not be assessed from the included studies. Levels of risk of bias were inconsistent and the clinical feasibility for routine inclusion of patients with bacterial meningitis was uncertain. The technological development within this field implies the need for further research.

Risk factors and prognosis of seizures in adults with community-acquired bacterial meningitis in Denmark: observational cohort studies.

OBJECTIVE: To examine predefined risk factors and outcome of seizures in community-acquired bacterial meningitis (CABM). DESIGN: Observational cohort studies SETTING: Denmark PARTICIPANTS: In the derivation cohort, we retrospectively included all adults (>15 years of age) with CABM in North Denmark Region from 1998 to 2014 and at Hvidovre and Hillerød hospitals from 2003 to 2014. In the validation cohort, we prospectively included all adults (>18 years of age) with CABM treated at all departments of infectious diseases in Denmark from 2015 to 2017. PRIMARY AND SECONDARY OUTCOME MEASURES: In the derivation cohort, we used modified Poisson regression to compute adjusted relative risks (RRs) with 95% confidence intervals for predefined risk factors for seizures during CABM as well as for risks of death and unfavourable outcome assessed by the Glasgow Outcome Scale score (1-4). Next, results were validated in the validation cohort. RESULTS: In the derivation cohort (n=358), risk factors for seizures at any time were pneumococcal aetiology (RR 1.69, 1.01-2.83) and abnormal cranial imaging (RR 2.27, 1.46-3.53), while the impact of age >65 years and immunocompromise was more uncertain. Examining seizures occurring after admission, risk factors were abnormal cranial imaging (RR 2.23, 1.40-3.54) and immunocompromise (RR 1.59, 1.01-2.50). Seizures at any time were associated with increased risks of in-hospital mortality (RR 1.45, 1.01-2.09) and unfavourable outcome at discharge (RR 1.27, 1.02-1.60). In the validation cohort (n=379), pneumococcal aetiology (RR 1.69, 1.10-2.59) and abnormal cranial imaging (RR 1.68, 1.09-2.59) were confirmed as risk factors for seizures at any time. For seizures occurring after admission, only pneumococcal meningitis (RR 1.92, 1.12-3.29) remained significant. Seizures at any time were also associated with in-hospital mortality (RR 3.26, 1.83-5.80) and unfavourable outcome (RR 1.23, 1.00-1.52) in this cohort. CONCLUSIONS: Pneumococcal aetiology, immunocompromise and abnormal cranial imaging were risk factors for seizures in CABM. Seizures were strongly associated with mortality and unfavourable outcome.

Factors associated with the occurrence of hearing loss after pneumococcal meningitis.

BACKGROUND: On the basis of a nationwide registration during a 5-year period (1999-2003), the frequency and severity of hearing loss was investigated retrospectively in 343 consecutive Danish patients who survived pneumococcal meningitis, to identify important risk factors (including the pneumococcal serotype) for development of hearing loss. METHODS: Results of blood and cerebrospinal fluid (CSF) biochemistry, bacterial serotyping, follow-up audiological examinations, and medical records were collected, and disease-related risk factors for hearing loss were identified. The mean pure-tone hearing threshold levels were compared with normative data. RESULTS: Of 240 patients examined by use of audiometry, 129 (54%) had a hearing deficit, and 50 (39%) of these 129 patients were not suspected of hearing loss at discharge from hospital. Of the 240 patients, 16 (7%) had profound unilateral hearing loss, and another 16 (7%) had bilateral profound hearing loss. Significant risk factors for hearing loss were advanced age, the presence of comorbidity, severity of meningitis, a low CSF glucose level, a high CSF protein level, and a certain pneumococcal serotype (P < .05). By applying multivariate logistic regression analysis, we found that advanced age, female sex, and a certain serotype were significant risk factors, because fewer patients with serotype 6B had hearing loss than did patients with serotype 12F (P = .03), which was the most commonly occurring serotype. CONCLUSION: Hearing loss is common after pneumococcal meningitis, and audiometry should be performed on all those who survive pneumococcal meningitis. Important risk factors for hearing loss are advanced age, female sex, severity of meningitis, and bacterial serotype.

Systemic steroid reduces long-term hearing loss in experimental pneumococcal meningitis.

OBJECTIVES/HYPOTHESIS: Sensorineural hearing loss is a common complication of pneumococcal meningitis. Treatment with corticosteroids reduces inflammatory response and may thereby reduce hearing loss. However, both experimental studies and clinical trials investigating the effect of corticosteroids on hearing loss have generated conflicting results. The objective of the present study was to determine whether systemic steroid treatment had an effect on hearing loss and cochlear damage in a rat model of pneumococcal meningitis. STUDY DESIGN: Controlled animal study of acute bacterial meningitis. METHODS: Adult rats were randomly assigned to two experimental treatment groups: a group treated with systemic steroid (n = 13) and a control group treated with saline (n = 13). Treatment was initiated 21 hours after infection and repeated once a day for three days. Hearing loss and cochlear damage were assessed by distortion product otoacoustic emissions (DPOAE), auditory brainstem response (ABR) at 16 kHz, and spiral ganglion neuron density. RESULTS: Fifty-six days after infection, steroid treatment significantly reduced hearing loss assessed by DPOAE (P < .05; Mann-Whitney) and showed a trend toward reducing loss of viable neurons in the spiral ganglion (P = .0513; Mann-Whitney). After pooling data from day 22 with data from day 56, we found that systemic steroid treatment significantly reduced loss of spiral ganglion neurons (P = .0098; Mann-Whitney test). CONCLUSIONS: Systemic steroid treatment reduces long-term hearing loss and loss of spiral ganglion neurons in experimental pneumococcal meningitis in adult rats. The findings support a beneficial role of anti-inflammatory agents in reducing hearing loss and cochlear damage in meningitis.

Intratympanic steroid prevents long-term spiral ganglion neuron loss in experimental meningitis.

HYPOTHESIS: Intratympanic steroid treatment prevents hearing loss and cochlear damage in a rat model of pneumococcal meningitis. BACKGROUND: Sensorineural hearing loss is a long-term complication of meningitis affecting up to a third of survivors. Streptococcus pneumoniae is the bacterial species most often associated with a hearing loss. METHODS: Rats were randomly assigned to 3 treatment groups: a group treated with intratympanic betamethasone and 2 control groups treated with either intratympanic or systemic saline. Treatment was initiated 21 hours after infection and repeated once a day for 3 days. Hearing loss and cochlear damage were assessed by distortion product otoacoustic emissions, auditory brainstem response at 16 kHz, and spiral ganglion neuron density. RESULTS: Fifty-six days after infection, auditory brainstem response showed no significant differences between groups, and distortion product otoacoustic emissions showed significant hearing loss at the low frequencies in animals treated with intratympanic steroid compared with animals treated with systemic saline (p < 0.05; Mann-Whitney test). However, intratympanic steroid significantly increased the number of viable neurons in the spiral ganglion compared with both intratympanic and systemic saline (p = 0.0082 and p = 0.0089; Mann-Whitney test). Histology revealed fibrosis of the tympanic membrane and cavity in steroid-treated animals, which plausibly caused the low-frequency hearing loss. CONCLUSION: Intratympanic betamethasone treatment prevents long-term spiral ganglion neuron loss in experimental pneumococcal meningitis. This finding is clinically relevant in relation to post-meningitic hearing rehabilitation by cochlear implantation. However, the drug instillation in the middle ear induced local fibrosis and a concurrent low-frequency hearing loss.

Routes, dynamics, and correlates of cochlear inflammation in terminal and recovering experimental meningitis.

OBJECTIVES/HYPOTHESIS: To examine the routes, dynamics and correlates of cochlear inflammation in meningitis to provide information on the pathogenesis of the associated hearing loss and indications for rational pharmacotherapeutical intervention. STUDY DESIGN: A well-established rat model of Streptococcus pneumoniae meningitis was employed. METHODS: Eight rats were inoculated intrathecally and not treated, whereas 26 were inoculated and treated with ceftriaxone. Six rats were sham-inoculated, making a total of 40 rats. The rats were sacrificed when reaching terminal illness or after 7 days, followed by light microscopy. Routes of cochlear inflammatory infiltration were examined. The volume fraction of inflammatory infiltration was estimated and correlated to bacterial and leukocyte counts in cerebrospinal fluid (CSF) and blood. RESULTS: The perilymphatic space was infiltrated with inflammatory cells via cochlear aqueduct, whereas the endolymphatic space was infiltrated from the spiral ligament. Rosenthal's canal was infiltrated through osseous spiral lamina canaliculi. In the untreated group, the degree of inflammation correlated with time of death, whereas antibiotic treatment reversed this development. Perilymphatic inflammation correlated significantly with the CSF leukocyte count, whereas endolymphatic inflammation correlated with spiral ligament inflammation. CONCLUSIONS: Meningogenic inflammation of the rat cochlea occurs via the cochlear aqueduct and the spiral ligament capillary bed. The spiral ganglion is infiltrated through the osseous spiral lamina. The degree of inflammation correlates positively with time of death in untreated meningitis, whereas antibiotic treatment leads to subsiding infiltration during recovery.