Infections and ischemic stroke outcome

The impact of dysbiosis in oropharyngeal and gut microbiota on systemic inflammatory response and short-term prognosis in acute ischemic stroke with preceding infection

Background

Stroke is a devastating disease and ranks as the second leading cause of death and disability globally. Several studies have shown that preceding infection (PI) of upper respiratory tract are strongly associated with acute ischemic stroke (AIS). However, the clinical implications and underlying pathological mechanisms remain unclear.

Methods

In this study, 16S rRNA gene sequencing was employed to compare the structural characteristics of oropharyngeal and gut microbiota in AIS patients with or without PI and normal controls (NCs; 30 cases each), and systemic inflammatory markers were detected to explore the relationship between upper respiratory tract infections (URTIs) and subsequent stroke severity and functional outcome and the potential mechanism.

Results

We found that patients with AIS-PI exhibited elevated serum WBC, NE, CRP, and Hcy levels, as well as a higher 90-day mRS score. Oropharyngeal and gut microbiota analysis showed that AIS and AIS-PI patients exhibited increased microbial richness in sequence. Principal coordinate analysis of the microbiota demonstrated significant differences in microbiota composition among the three groups. In AIS-PI patients, Megamonas, Megasphaera, Ruminococcaceae UCG 004, Rothia, and Streptococcus were significantly enriched in the gut. Opportunistic pathogens, including Thermus, uncultured Veillonella sp., and Oribacterium sinu, were found to be significantly enriched in the oropharynx. The dysregulated microbiota were positively correlated with systemic inflammatory markers, stroke severity, and poor prognosis. In contrast, short-chain fatty acid-producing bacteria Eisenbergiella, bacterium NLAE, Fusicatenibacter, Ruminococcaceae, and Faecalibacterium were enriched in NCs. Their abundances were negatively correlated with systemic inflammatory markers, stroke severity and poor prognosis.

Conclusion

Our findings suggest that PIs of the upper respiratory tract may contribute to poor short-term functional outcome in AIS patients by causing disturbance of the oropharyngeal and gut microbiota and promoting elevated systemic inflammation levels.

Stroke risk after varicella-zoster virus infection: a systematic review and meta-analysis

Varicella-zoster virus (VZV) infection may cause vascular inflammatory changes leading to an increased risk of stroke. Previous studies have focused on the risk of stroke and less on changes in stroke risk and prognosis. We aimed to explore the changing patterns of stroke risk and stroke prognosis after VZV infection. This study is a systematic review and meta-analysis. We searched PubMed, Embase, and the Cochrane Library for studies on stroke after VZV infection between January 1, 2000, and October 5, 2022. Relative risks were combined for the same study subgroups using a fixed-effects model and pooled across studies using a random-effects model. 27 studies met the requirements, including 17 herpes zoster (HZ) studies and ten chickenpox studies. There was an increased risk of stroke after HZ, and this risk decreased over time: relative risk 1.80 (95% CI 1.42-2.29) within 14 days, 1.61 (95% CI 1.43-1.81) within 30 days, 1.45 (95% CI 1.33-1.58) within 90 days, 1.32 (95% CI 1.25-1.39) within 180 days, 1.27 (95% CI 1.15-1.40) at one year and 1.19 (95% CI 0.90-1.59) after one year, with the same trend in the stroke subtype. The risk of stroke after herpes zoster ophthalmicus was higher, with a maximum relative risk of 2.26 (95% CI 1.35-3.78). The risk of stroke after HZ was higher in patients aged around 40 years: relative risk 2.53 (95% CI 1.59-4.02), and similar in men and women. Also, after pooling studies of post-chickenpox stroke, we found that the middle cerebral artery and its branches were most frequently involved (78.2%), with a better prognosis in most patients (83.1%) and less frequent vascular persistence progression (8.9%). In conclusion, the risk of stroke increases after VZV infection, decreasing over time. Post-infection vascular inflammatory changes often occur in the middle cerebral artery and its branches, with a better prognosis in most patients and less frequent persistent progression.

Determinants of urinary tract infection in hospitalized patients with acute ischemic stroke

BACKGROUND

Stroke is a major cause of morbidity and mortality worldwide. Urinary tract infection (UTI) is a common post-acute ischemic stroke (AIS) complication. We assessed the incidence, determinant factors, infection characteristics, post-stroke complications, and outcomes of hospitalized AIS patients with UTI.

METHODS

This retrospective cohort study included AIS patients admitted within 7 days of stroke onset. The patients were divided into the UTI group and the non-UTI (control) group. Clinical data were collected and compared between the groups.

RESULTS

There were 342 AIS patients (31 with UTIs and 311 controls). The multivariate analysis showed that an initial National Institutes of Health Stroke Scale (NIHSS) score of ≥ 15 (odds ratio [OR] 5.00, 95% confidence interval [CI] 1.33-18.72) and Foley catheter retention (OR 14.10, 95% CI 3.25-61.28) were risk factors for UTI, whereas smoking (OR 0.08, 95% CI 0.01-0.50), an initial systolic blood pressure (SBP) of > 120 mmHg (OR 0.06, 95% CI 0.01-0.31), and statin use (OR 0.02, 95% CI 0.0006-0.42) were protective factors. Twenty cases (64.5%) were community-acquired and 11 cases (35.3%) were hospital-acquired. Ten patients (32.3%) had catheter-associated UTIs. The most common pathogen was Escherichia coli (13 patients, 41.9%). Post-stroke complications were significantly more common in the UTI group, including pneumonia, respiratory failure, sepsis, brain edema, seizure, symptomatic hemorrhagic transformation, congestive heart failure, atrial fibrillation with a rapid ventricular response, acute kidney injury, and hyponatremia. The median length of stay (LOS) in the UTI group was 12 days versus 3 days in the control group (p < 0.001). The median 3-month modified Rankin Scale score was higher (5 in UTI and 2 in control; p < 0.001) and the median 3-month Barthel Index was lower (0 in UTI and 100 in control; p < 0.001) in the UTI group than in the control group.

CONCLUSIONS

The risk factors for post-AIS UTI included severe stroke (NIHSS score ≥ 15) and urethral catheter indwelling. An initial SBP of > 120 mmHg and statin use were protective factors. The UTI group had significantly worse post-stroke complications, a longer LOS, and worse 3-month outcomes. Smoking was protective, which requires further investigation.

Acute Routine Leukocyte and Neutrophil Counts Are Predictive of Poststroke Recovery at 3 and 12 Months Poststroke: An Exploratory Study

Background and Aims. White blood cell (WBC) and neutrophil counts (NC) are common markers of inflammation and neurological stroke damage and could be expected to predict poststroke outcomes. Objective. The aim of this study was to explore the prognostic value of early poststroke WBC and NC to predict cognition, mood, and disability outcomes at 3 and 12 months poststroke. Methods. Routine clinical analyses WBC and NC were collected at 3 time points in the first 4 days of hospitalization from 156 acute stroke patients. Correlations using hierarchical or ordinal regressions were explored between acute WBC and NC and functional recovery, depression, and cognition at 3 and 12 months poststroke, after covarying for age and baseline stroke severity. Results. We found significant increases in NC between <12 hours and 24 to 48 hours time points (P = .05). Hierarchical regressions, covaried for age and baseline stroke severity, found that 24 to 48 hours WBC (P = .05) and NC (P = .04) significantly predicted 3-month cognition scores. Similarly, 24 to 48 hours WBC (P = .05) and NC (P = .02) predicted cognition scores at 12 months. Increases in WBC and NC were predictive of increased cognition scores at both 3 and 12 months (positive recovery) though there were no significant associations between WBC and NC and disability or depression scores. Conclusions. Routine acute stroke clinical laboratory tests such as WBC and NC taken between 24 and 48 hours poststroke are predictive of cognition poststroke. It is interpreted that higher rapid immunological activation in the acute phase is an indicator for the trajectory of positive stroke recovery.

Peripheral inflammation preceeding ischemia impairs neuronal survival through mechanisms involving miR-127 in aged animals

Ischemic stroke, the third leading cause of death in the Western world, affects mainly the elderly and is strongly associated with comorbid conditions such as atherosclerosis or diabetes, which are pathologically characterized by increased inflammation and are known to influence the outcome of stroke. Stroke incidence peaks during influenza seasons, and patients suffering from infections such as pneumonia prior to stroke exhibit a worse stroke outcome. Earlier studies have shown that comorbidities aggravate the outcome of stroke, yet the mediators of this phenomenon remain obscure. Here, we show that acute peripheral inflammation aggravates stroke‐induced neuronal damage and motor deficits specifically in aged mice. This is associated with increased levels of plasma proinflammatory cytokines, rather than with an increase of inflammatory mediators in the affected brain parenchyma. Nascent transcriptomics data with mature microRNA sequencing were used to identify the neuron‐specific miRNome, in order to decipher dysregulated miRNAs in the brains of aged animals with stroke and co‐existing inflammation. We pinpoint a previously uninvestigated miRNA in the brain, miR‐127, that is highly neuronal, to be associated with increased cell death in the aged, LPS‐injected ischemic mice. Target prediction tools indicate that miR‐127 interacts with several basally expressed neuronal genes, and of these we verify miR‐127 binding to Psmd3. Finally, we report reduced expression of miR‐127 in human stroke brains. Our results underline the impact of peripheral inflammation on the outcome of stroke in aged subjects and pinpoint molecular targets for restoring endogenous neuronal capacity to combat ischemic stroke.

Epidemiology, Risk Factors, and Predictors of Disability in a Cohort of Jordanian Patients with the First Ischemic Stroke

OBJECTIVE

To identify the risk factors, etiologies, length of stay, severity, and predictors of disability among patients with the first ischemic stroke in Jordan.

METHODS

A retrospective cohort study of 142 patients who were admitted to the Neurology Department at King Abdullah University Hospital between July/2017 and March/2018 with a first ischemic stroke. Etiology was classified according to the TOAST criteria. Severity was represented by NIHSS score, disability by mRS score, and prolonged length of stay as hospitalizations more than 75th percentile of the cohort's median length of stay. Analysis of the sample demographics and descriptive statistics were done, including frequencies of prevalence of independent variables (risk factors) and frequencies of stroke and etiology work-up. Chi-square and univariate analysis of variance "ANOVA" were used to investigate the relationship between risk factors and type of stroke. Finally, logistic regression analysis was used to measure the contribution of each of the independent variables. IRB approval was obtained as necessary.

RESULTS

The mean age for the cohort was 66.5 years. The most common risk factors were hypertension (78.8%), diabetes mellitus (60.5%), and ischemic heart disease (29.4%). The most common stroke etiology was small-vessel occlusion (54.2%). Median length of stay was 4 days. Prolonged length of stay was observed in 23.23% of patients, which was associated with several factors, the most common of which were persistent dysphagia (57.5%), nosocomial infection (39.3%), and combined dysphagia and nosocomial infection (21.2%). The mean admission NIHSS score was 7.94, and on discharge was 5.76. In-hospital mortality was 2.81%, while 50% of patients had a favorable outcome on discharge (mRS score between 0-2). The mean discharge mRS score for the cohort was 2.47 (SD ± 1.79). Large artery atherosclerosis was associated with the highest residual disability with a mean score of 3.67 (SD ± 1.88), while the stroke of undetermined etiology was associated with the lowest residual disability with a mean score of 1.60 (SD ± 1.78). Significant predictors of mRS score were smoking (t 3.24, P < 0.001), age (t 1.98, P < 0.049), and NIHSS score (t 9.979, P 0.000).

CONCLUSION

Ischemic strokes have different etiologies that are associated with different levels of impact on the patient's clinical status and prognosis. Large artery atherosclerosis was associated with the highest residual disability. Regarding predictors of prognosis, current smoking status, age above 50, gender, and NIHSS on admission appear to be the strongest predictors of prognosis. Finally, higher NIHSS score on admission resulted in a longer hospital stay.

Increased burden of rare deleterious variants of the KCNQ1 gene in patients with large‑vessel ischemic stroke

The impact of rare and damaging variants in genes associated with platelet function in large‑vessel ischemic stroke (LVIS) remains unknown. The aim of this study was to investigate the contribution of some of these variants to the genetic susceptibility to LVIS in Polish patients using a deep re‑sequencing of 54 selected genes, coding for proteins associated with altered platelet function. Targeted pooled re‑sequencing (Illumina HiSeq 2500) was performed on genomic DNA of 500 cases (patients with history of clinically proven diagnosis of LVIS) and 500 age‑, smoking status‑, and sex‑matched controls (no history of any type of stroke), and from the same population as patients with LVIS. After quality control and prioritization based on allele frequency and damaging probability, individual genotyping of all deleterious rare variants was performed in patients from the original cohort, and stratified to concomitant cardiac conditions differing between the study and stroke groups. We demonstrated a statistically significant increase in the number of rare and potentially damaging variants in some of the investigated genes in the LVIS pool (an increase in the genomic variants burden). Furthermore, we identified an association between LVIS and 6 rare functional and damaging variants in the Kv7.1 potassium channel gene (KCNQ1). The predicted functional properties (partial loss‑of function) for the three most damaging variants in KCNQ1 coding locus were further confirmed in vitro by analyzing the membrane potential changes in cell lines co‑transfected heterogeneously with human muscarinic type 1 receptor and wild‑type or mutated KCNQ1 cDNA constructs using fluorescence imaging plate reader. The study demonstrated an increased rare variants burden for 54 genes associated with platelet function, and identified a putative role for rare damaging variants in the KCNQ1 gene on LVIS susceptibility in the Polish population.

Population-Specific Associations of Deleterious Rare Variants in Coding Region of P2RY1-P2RY12 Purinergic Receptor Genes in Large-Vessel Ischemic Stroke Patients

The contribution of low-frequency and damaging genetic variants associated with platelet function to ischemic stroke (IS) susceptibility remains unknown. We employed a deep re-sequencing approach in Polish patients in order to investigate the contribution of rare variants (minor allele frequency, MAF < 1%) to the IS genetic susceptibility in this population. The genes selected for re-sequencing consisted of 26 genes coding for proteins associated with the surface membrane of platelets. Targeted pooled re-sequencing (Illumina HiSeq 2500) was performed on genomic DNA of 500 cases (patients with history of clinically proven diagnosis of large-vessel IS) and 500 controls. After quality control and prioritization based on allele frequency and damaging probability, follow-up individual genotyping of deleterious rare variants was performed in patients from the original cohort. Gene-based analyses identified an association between IS and 6 rare functional and damaging variants in the purinergic genes (P2RY1 and P2RY12 locus). The predicted properties of the most damaging rare variants in P2RY1 and P2RY12 were confirmed by using mouse fibroblast cell cultures transfected with plasmid constructs containing cDNA of mutated variants (FLIPR on FlexStation3). This study identified a putative role for rare variants in P2RY1 and P2RY12 genes involved in platelet reactivity on large-vessel IS susceptibility in a Polish population.

Post-Stroke Bacteriuria: A Longitudinal Study among Stroke Outpatients and Inpatients at the Korle-Bu Teaching Hospital in Ghana

Infections of the urinary tract constitute an important post-stroke complication but in Africa, little is known about such infections in relation to stroke patients. The aim of the study was to investigate the epidemiology of bacteriuria among stroke patients at the Korle-Bu Teaching Hospital (KBTH) in Ghana including the prevalence, incidence, risk factors and aetiological agents. This was a longitudinal study involving 55 outpatients and 16 inpatients of stroke from the physiotherapy clinic and stroke admission ward of KBTH respectively. Urine cultures for inpatient subjects were done each day until the patient was discharged. With outpatients, urine specimens were analysed every week or two for 6 months. Information on demographics and clinical history of the study participants were extracted from their clinical records. The results showed that the prevalence of bacteriuria among stroke outpatients and inpatients were 10.9% (6/55) and 18.8% (3/16) respectively (p = 0.411). Among both the outpatients and inpatients, there was one new case of bacteriuria each during the period of follow-up. Overall, 1/9 (11%) of the bacteriuria cases among the stroke patients was symptomatic. Severe stroke (OR = 17.7, p = 0.008) and pyuria (OR = 38.7, p = 0.002) were identified as predictors of bacteriuria. Escherichia coli was the most common organism implicated in bacteriuria and was susceptible to amikacin, but resistant to augmentin, ampicillin, cefuroxime, cotrimoxazole, meropenem, norfloxacin and tetracycline. Overall, bacteriuria is a common complication among both stroke inpatients and outpatients at KBTH, though it appears to be more common among the former. Stroke severity appears to be the main stroke-related determinant of bacteriuria among stroke patients. Bacteriuria among stroke patients is mainly asymptomatic and E. coli is the most important aetiological agent.

Association between Atrial Fibrillation and Three-Year Mortality in Nondiabetic Patients with Acute First-Ever Ischemic Stroke

BACKGROUND

Diabetes mellitus (DM) is a risk factor for atrial fibrillation (AF) and is known to be an important risk factor for death from stroke. The influence of AF on long-term outcomes in patients with ischemic stroke remains controversial. To clarify the exact influence of AF on stroke outcome and exclude the effect from DM, we investigated the influence of AF on the 3-year outcomes of nondiabetic patients with acute first-ever ischemic stroke.

METHODS

Five-hundred seventy-four nondiabetic patients with acute first-ever ischemic stroke were enrolled and had been followed for 3 years. Patients were divided into 2 groups according to whether AF was diagnosed or not. Clinical presentations, risk factors for stroke, laboratory data, comorbidities, and outcomes were recorded.

RESULTS

A total of 107 patients (18.6%) had AF. The age was significantly older in patients with AF. Total anterior circulation syndrome occurred more frequently among patients with AF (P < .001). The mean length of stay in the acute ward was significantly higher in patients with AF (P < .001). Furthermore, dependent functional status following discharge was higher in patients with AF (P < .001). Multivariate Cox regression revealed that AF is a significant predictor of 3-year all-cause mortality (hazard ratio = 1.98, 95% confidence interval = 1.07-3.67, P = .022).

CONCLUSIONS

AF is associated with increased risk of 3-year mortality in nondiabetic patients with acute first-ever ischemic stroke. Careful cardiac evaluation and treatment are essential in patients with AF and stroke.

Lipopolysaccharide exacerbates infarct size and results in worsened post-stroke behavioral outcomes

Background

A third of ischemic stroke cases have no traditional underlying causes such as hypertension, diabetes, atherosclerosis, obesity, or age. Moreover, thirty to forty percent of strokes occur during or acutely after an active infection and the incidence of stroke increases during flu season. We and others have shown that the combination of a minor bacterial infection mimic, 100 μg/kg of lipopolysaccharide (LPS) prior to a minor stroke—30 min transient middle cerebral artery occlusion (tMCAO)—exacerbates infarct volume in a mouse model. Thus, experimental and epidemiological data strongly suggest that infection and/or inflammation play a role in stroke occurrence and severity. However, to date, long-term outcomes of stroke during an active infection has not been studied.

Methods

3–4 month old C57Bl6/J mice were treated with saline or LPS 30 min prior to a 30 min tMCAO or sham surgery. A behavioral battery was administered to assess health status/sickness behavior, neurological deficits, motor, cognitive, and affective behaviors.

Results

We show for the first time that exposure to a low dose of LPS prior to a mild stroke significantly worsens neurological deficits and sickness scores. Motor, cognitive, and affective behaviors were assessed post-stroke and while stroke significantly affected motor behavior on rotarod, LPS did not increase the motor deficits. We did not observe any effects of stroke or LPS on cognitive and affective behaviors.

Conclusions

Our observations of the association between infection, stroke, and worse sickness and neurological outcomes identify (1) a clinical need to aggressively treat infections in people with risk factors for stroke and (2) the need to understand the mechanism(s) of the association between infections and stroke.

Electronic supplementary material

The online version of this article (doi:10.1186/s12993-015-0077-5) contains supplementary material, which is available to authorized users.

Stroke, mTBI, infection, antibiotics and beta blockade: Connecting the dots

Several themes supported by a robust literature are addressed in this clinical translational review and research paper: (1) the inadequate standard of care for minimal traumatic brain injury (mTBI)/concussion when compared to stroke because diagnosis and care for mTBI/concussion are based primarily on a symptom only framework; (2) the treatment of stroke (brain injury) infection with select antibiotics; (3) the use of beta blockade in stroke (brain injury). The various etiologies of brain injury appear to coalesce to common endpoints: potential neuronal demise, cognitive and functional losses, immune suppression and infection. The use of principles patterned after 'Koch's Postulates' (show/prove the presence of infection/illness/disease, treat until resolved, and prove objectively that the disease/illness is gone/healed/cured) appears to be marginalized in establishing a diagnosis and recovery from mTBI/TBI. The pathways of immune system interactions in stroke (brain injury) and infection are briefly discussed. The suggestion of combined specific antibiotic and beta blockade for ischemic stroke (brain injury) and mTBI is advanced for treatment and expeditious further study. Stroke is considered a brain injury in this paper. Stroke is also considered and recommended as a study model for mTBI therapy because of their common end points from brain damage. It is suggested that potential transfer or translation of therapy for stroke may be useful in mTBI.

The influence of previous infections and antichlamydia pneumoniae seropositivity on functional outcome in ischemic stroke patients: results from the IN2 study

Although a growing attention is being paid to acute ischemic stroke patients, the correlation between clinical outcome and infectious events in this population has been poorly investigated. 749 ischemic stroke (mean age 71 years old, males 56%) patients were enrolled in this prospective case-control study by 11 Italian Stroke Units. Demographic data, vascular risk factors, previous infections and post-stroke infections (PSIs) were recorded. Blood samples were collected and the enzyme-linked immunoassay was chosen to measure Chlamydia pneumoniae IgG and IgA plasma antibodies (antibody titers were classified with specific cut-off levels: IgA > 1:16 and IgG > 1:64). Early poor outcome was defined as mRS score >2 at discharge, while poor outcome at 6-month follow-up. Univariate and multivariate analyses were performed. Median NIHSS was 7, IgA and IgG antichlamydia pneumoniae seropositivities were observed in 308 (37.1%) and 207 (23.6%) patients, respectively. Multivariate analyses showed significant correlations between PSIs and NIHSS (RR: 1.06; 95% CI 1.02-1.09; p < 0.001) and PSIs and IgA antichlamydia pneumoniae seropositivity (RR: 3.84; 95% CI 2.53-5.84; p < 0.001). Significant disability was associated with baseline NIHSS (RR: 1.32; 95% CI 1.16-1.50; p < 0.001), IgA (RR: 2.67; 95% CI 1.06-6.70; p = 0.035) and IgG antichlamydia (RR: 5.75; 95% CI 1.83-18.03; p = 0.003) seropositivity and atrial fibrillation (RR: 2.58; 95% CI 1.81-3.67; p < 0.001). While previous infections were not associated with functional outcome, antichlamydia antibodies play a negative role in ischemic stroke patients. Preventive strategies may reduce the stroke burden and improve the clinical outcome.

Routine serum C-reactive protein and stroke outcome after intravenous thrombolysis

OBJECTIVES

The clinical usefulness of blood biomarkers in acute stroke is not yet fully established, especially after thrombolytic therapy. Our aim was to investigate the association between routine serum C-reactive protein (CRP) measured within 24 h after admission and outcome in ischaemic stroke patients treated with intravenous thrombolysis, adjusting for a history of recent infection.

METHODS

We analysed the data of consecutive stroke patients who received intravenous alteplase in our centre between October 2003 and December 2011, collected in a detailed prospective registry. Routine serum CRP was measured within 24 h from admission; concentration >5 ng/ml was considered elevated.

RESULTS

Serum CRP was measured in 341 of 406 stroke patients treated with alteplase. Patients with elevated CRP (135/341, 42.5%) compared to those with normal CRP values, were significantly older, more frequently presented with a preexisting disability, comorbidities and suffered more severe strokes. They had a higher proportion of symptomatic intracranial haemorrhage according to ECASS II definition (7.2% vs 1.6%, P = 0.010), higher 3-month mortality (25.6% vs 11.3%, P = 0.001), and were less frequently alive and independent after 3 months (45.9% vs 63.7%, P = 0.002). However, those associations were not confirmed after adjustment for age, stroke severity, diabetes, congestive heart failure, lack of prestroke disability and signs of recent infection.

CONCLUSIONS

According to our findings, elevated routine serum CRP measured within 24 h after admission does not seem to independently affect the outcome in patients receiving intravenous thrombolysis for stroke. However, further studies of blood samples taken directly before the treatment are needed.

Epidemiologic features, risk factors, and outcome of sepsis in stroke patients treated on a neurologic intensive care unit

PURPOSE

Because of the immune-suppressive effect of cerebral damage, stroke patients are at high risk for infections. These might result in sepsis, which is the major contributor to intensive care unit (ICU) mortality. Although there are numerous studies on infections in stroke patients, the role of sepsis as a poststroke complication is unknown.

METHODS

We retrospectively analyzed incidence of and risk factors for sepsis acquisition as well as outcome parameters of 238 patients with ischemic or hemorrhagic strokes consecutively admitted to the neurologic ICU in a tertiary university hospital between January 1, 2009, and December 31, 2010. Basic demographic and clinical data including microbiological parameters as well as factors describing stroke severity (eg, lesion volume and National Institute of Health stroke scale score) were recorded and included into the analysis. The diagnosis of sepsis was based on the criteria of the German Sepsis Society.

RESULTS

We identified 30 patients (12.6%) with sepsis within the first 7 days from stroke onset. The lungs were the most frequent source of infection (93.3%), and gram-positive organisms were dominating the microbiologic spectrum (52.4%). Comorbidities (chronic obstructive pulmonary disease and immunosuppressive disorders) and Simplified Acute Physiology Score II but none of the factors describing stroke severity were independent predictors of sepsis acquisition. Sepsis was associated with a significantly worse prognosis, leading to a 2-fold increased mortality rate during in-hospital care (36.7% vs 18.8%) and after 3 months (56.5% vs 28.5%), but only in the subgroup of supratentorial hemorrhages, it was an independent predictor of in-hospital and 3-month mortality. Other factors significantly associated with death in a multivariate analysis were chronic obstructive pulmonary disease, malignancies (in-hospital mortality only), and Simplified Acute Physiology Score II (3-month mortality only) for ischemia and heart failure (in-hospital mortality only), National Institute of Health stroke scale score (in-hospital mortality only), and stroke volume for hemorrhages, respectively.

CONCLUSIONS

Sepsis seems to be a frequent complication of stroke patients requiring neurologic ICU treatment. Predictors of sepsis acquisition in our study were comorbidities and severity of deterioration of physiological status, but not stroke severity. A better understanding of risk factors is important for prevention and early recognition, whereas knowledge of outcome may help in prognosis prediction. Further studies are needed to clarify the optimal preventive treatment for these patients.

The role of inflammation and interleukin-1 in acute cerebrovascular disease

Acute cerebrovascular disease can affect people at all stages of life, from neonates to the elderly, with devastating consequences. It is responsible for up to 10% of deaths worldwide, is a major cause of disability, and represents an area of real unmet clinical need. Acute cerebrovascular disease is multifactorial with many mechanisms contributing to a complex pathophysiology. One of the major processes worsening disease severity and outcome is inflammation. Pro-inflammatory cytokines of the interleukin (IL)-1 family are now known to drive damaging inflammatory processes in the brain. The aim of this review is to discuss the recent literature describing the role of IL-1 in acute cerebrovascular disease and to provide an update on our current understanding of the mechanisms of IL-1 production. We also discuss the recent literature where the effects of IL-1 have been targeted in animal models, thus reviewing potential future strategies that may limit the devastating effects of acute cerebrovascular disease.

Activation of immune responses to brain antigens after stroke

Infection is common after stroke and is independently associated with a worse outcome. The predisposition to infection following stroke is in part related to a sympathetically mediated suppression of the peripheral immune response. The teleological explanation for this immune dysfunction is that it serves to prevent autoimmune responses to brain antigens. We believe that the systemic immune response in patients who develop infection, however, thwarts this seemingly protective response and predisposes to central nervous system autoimmunity. These autoimmune responses may mediate, at least in part, the worse outcome associated with post-stroke infection.